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diff --git a/old/53139-0.txt b/old/53139-0.txt deleted file mode 100644 index dd4ddd4..0000000 --- a/old/53139-0.txt +++ /dev/null @@ -1,15148 +0,0 @@ -The Project Gutenberg eBook, Maxims and Instructions for the Boiler Room, -by N. (Nehemiah) Hawkins - - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms of -the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - - - - -Title: Maxims and Instructions for the Boiler Room - Useful to Engineers, Firemen & Mechanics; Relating to Steam Generators, Pumps, Appliances, Steam Heating, Practical Plumbing, etc. - - -Author: N. (Nehemiah) Hawkins - - - -Release Date: September 24, 2016 [eBook #53139] - -Language: English - -Character set encoding: UTF-8 - - -***START OF THE PROJECT GUTENBERG EBOOK MAXIMS AND INSTRUCTIONS FOR THE -BOILER ROOM*** - - -E-text prepared by deaurider, Brian Wilcox, and the Online Distributed -Proofreading Team (http://www.pgdp.net) from paage images generously made -available by Internet Archive (https://archive.org) - - - -Note: Project Gutenberg also has an HTML version of this file - which includes the more than 200 original illustrations. - See 53139-h.htm or 53139-h.zip: - (http://www.gutenberg.org/files/53139/53139-h/53139-h.htm) - or - (http://www.gutenberg.org/files/53139/53139-h.zip) - - - Images of the original pages are available through - Internet Archive. See - https://archive.org/details/maximsinstructio00hawk - - -Transcriber’s note: - - Text enclosed by underscores is in italics (_italics_). - - Text enclosed by equal signs is in bold face (=bold=). - - Text enclosed by plus signs is in bold face and underscored - (+bold and underscored+). - - A detailed transcriber’s note is at the end of the book. - - - - - -MAXIMS AND INSTRUCTIONS FOR THE BOILER ROOM. - - -[Illustration: HAWKINS’ EDUCATIONAL WORKS FOR ENGINEERS] - - - _This Work is Fraternally inscribed to W. R. Hawkins, R. F. Hawkins - and F. P. Hawkins._ - - -[Illustration: RICHARD TREVITHICK.] - - -MAXIMS AND INSTRUCTIONS FOR THE BOILER ROOM. - -Useful to Engineers, Firemen & Mechanics, - -Relating to Steam Generators, Pumps, -Appliances, Steam Heating, Practical -Plumbing, etc. - - -[Illustration] - - -by - -N. HAWKINS, M. E., - -Honorary Member National Association of Stationary Engineers, Editorial -Writer, Author of Hand Book of Calculations for Engineers and Firemen, -Etc., Etc. - -Comprising Instructions and Suggestions on the Construction, Setting, -Control and Management of Various Forms of Steam Boilers; on the Theory -and Practical Operation of the Steam Pump; Steam Heating; Practical -Plumbing; also Rules for the Safety Valve, Strength of Boilers, -Capacity of Pumps, etc. - - - - - - - -Theo. Audel & Co., Publishers, -63 Fifth Ave., Cor. 13th St., -New York. - -Copyrighted -1897—1898—1903 -by -Theo, Audel & Co. - - - - -_PREFACE._ - - -_The chief apology for the preparation and issue of these Maxims and -Instructions, for the use of Steam users, Engineers and Firemen, is the -more than kind reception of Calculations._ - -_But there are other reasons. There is the wholesome desire to benefit -the class, with whom, in one way and another, the author has been -associated nearly two score years._ - -_The plan followed in this work will be the same as that so generally -approved in Calculations; the completed volume will be a work of -reference and instruction upon those works set forth in the title page. -As a work of reference the work will be especially helpful through -combined Index and Definition Tables to be inserted at the close of the -book. By the use of these the meaning of every machine, material and -performance of the boiler room can be easily found and the “points” of -instruction made use of._ - -_This work being issued in parts, now in manuscript, and capable of -change or enlargement, the editor will be thankful for healthful -suggestions from his professional brethren, before it is put into -permanent book form._ - -[Illustration: OLIVER EVANS. - -GEORGE STEPHENSON. - -ROBERT FULTON.] - - - - -CONTENTS. - - Page - PREFACE 7 - INTRODUCTION 9 - MATERIALS 12 - Coal 13 - Wood 14 - Peat 14 - Tan 15 - Straw 15 - Coke, Charcoal, Peat Charcoal 15 - Liquid and Gas Fuels 15 - Air 16 - Table of Evaporation 18 - Fire Irons 19 - Handy Tools 21 - The Tool Box 22 - THE FIRING OF STEAM BOILERS 24 - Directions for Firing with Various Fuels 28 - Firing with Coke 28 - Firing with Coal Tar 30 - Firing with Straw 31 - Firing with Oil 32 - Firing on an Ocean Steamer 32 - Firing of Sawdust and Shavings 33 - Firing a Locomotive 36 - Firing with Tan Bark 36 - Points Relating to Firing 37 - Foaming in Boilers 42 - A CHAPTER OF DON’TS 44 - STEAM GENERATORS 48 - Description 49 - An Upright Steam Boiler 50 - The Growth of the Steam Boiler 52 - Marine Boilers 60 - The Surface Condenser 65 - Operation of the Condenser 66 - Water Tube Steam Boilers 67 - Care of Water Tube Boilers 70 - Sectional Boilers 71 - Locomotive Boilers 72 - Standard Horizontal Tubular Steam Boiler 79 - Parts of the Tubular Boiler 81 - The Triple Draught Tubular Boiler 83 - SPECIFICATION FOR 125 HORSE POWER BOILER 85 - Type 85 - Dimensions 85 - Quality and Thickness of Steel Plates 85 - Flanges 85 - Riveting 86 - Braces 86 - Manholes, Hand Holes and Thimbles 86 - Lugs 86 - Castings 86 - Testing 87 - Quality and Workmanship 87 - Fittings and Mountings 87 - Drawings 87 - Duty of Boiler 87 - MARKS ON BOILER PLATES 88 - CONSTRUCTION OF BOILERS 89 - Quality of Steel Plates 90 - Nickel Steel Boiler Plates 91 - Riveting 91 - Bracing of Steam Boilers 96 - Rule for Finding Pressure or Strain - on Bolts 99 - Gusset Stays 100 - Riveted or Screw Stays 101 - Inspector’s Rules Relating to Braces in - Steam Boilers 102 - Rules and Tables 105 - Boiler Tubes 110 - Portions of the Marine Boiler which - become Thin by Wear 112 - EXAMPLES OF CONSTRUCTION AND DRAWING 113 - Rule for Safe Internal Pressure 117 - DEFINITION OF TERMS 121 - Tensile strength 121 - Contraction of area 121 - Elongation 121 - Shearing strength 121 - Elastic limit 121 - Tough 121 - Ductile 121 - Elasticity 122 - Fatigued 122 - Malleable 122 - Weldable 122 - Cold-short 122 - Hot-short 122 - Homogeneous 122 - BOILER REPAIRS 123 - Repairing Cracks 123 - Defects and Necessary Repairs 124 - Questions - by the Proprietor to the Engineer in - Charge, Relating to Condition of the - Boiler 127 - Questions - asked of a Candidate For a Marine - License Relating to Defects in Boiler 127 - THE INSPECTION OF STEAM BOILERS 129 - How to prepare for Steam Boiler - Inspection 130 - Issuing Certificates 131 - The Hydraulic Test 131 - ENGINEERS’ EXAMINATIONS 133 - MECHANICAL STOKERS 134 - CHEMICAL TERMS AND EXPLANATIONS - RELATING TO FEED WATERS 136 - Chemistry 136 - Element 136 - Re-agent 136 - Oxide 136 - Carbonate 136 - Acid 137 - Alkalies 137 - Chloride 137 - Sulphates 137 - Silica 137 - Magnesia 138 - Carbonate of Magnesia 138 - Lime 138 - Soda 138 - Sodium 138 - Salt 139 - ANALYSIS OF FEED WATER 140 - Directions 140 - FROM ARGOS, IND. 140 - FROM SIOUX FALLS, S. D. 140 - FROM LITCHFIELD, ILL. 141 - FROM CHELSEA, MASS. 141 - FROM MEMPHIS, TENN. 141 - FROM PEKIN, ILL. 141 - FROM TIFFIN, OHIO 141 - CORROSION AND INCRUSTATION OF STEAM BOILERS 142 - Preliminary Precipitation of Water 144 - A precipitator for Sea Water 145 - Scale Deposited in Marine Boilers 146 - A locomotive-Boiler Compound 149 - “Points” Relating to the Scaling of - Steam Boilers 149 - ENGINEERS’ TESTS FOR IMPURITIES IN - FEED WATER 153 - Use of Petroleum Oil in Boilers 155 - Kerosene Oil in Boilers 156 - Mechanical Boiler Cleaners 159 - Scumming Apparatus 161 - Use of Zinc in Marine Boilers 162 - BOILER FIXTURES AND BELONGINGS 164 - Boiler Fronts 165 - Furnace Doors 168 - Fusible Plugs 171 - Grate Bars 173 - Water Gauge Cocks 176 - Glass Gauges 177 - The Mud Drum 179 - Baffle Plates 180 - Dead Plate 180 - Steam Whistles 180 - The Steam Gauge 181 - Steam Separator 183 - Sentinel Valve 184 - Damper Regulators 185 - Fuel Economizer and Feed Water Purifier 185 - Safety Valves 187 - U. S. Rules Relating to Safety Valves 189 - Feed Water Heaters 196 - Capacity of Cisterns 202 - Water Meters 203 - “Points” Relating to Water Meters 204 - The Steam Boiler Injector 206 - “Points” Relating to the Injector 209 - LAWS OF HEAT 212 - THE STEAM PUMP 215 - Classification of Pumps 217 - Points Relating to Pumps 219 - Calculations Relating to Pumps 222 - IMPORTANT PRINCIPLES RELATING TO WATER 224 - STORING AND HANDLING OF COAL 225 - CHEMISTRY OF THE FURNACE 226 - Oxygen 229 - Carbon 229 - Hydrogen 230 - Nitrogen 230 - Sulphur 230 - Carbonic Acid Gas 230 - Carbonic Oxide 231 - Table 231 - HEATPROOF AND ORNAMENTAL PAINTS 232 - PRESSURE RECORDING GAUGE 233 - HORSE POWER AS APPLIED TO BOILERS 234 - Rule For Estimating Horse Power of - Horizontal Tubular Steam Boilers 235 - BOILER SETTING 236 - Setting of Water Tube Boilers 239 - Points Relating to Boiler Setting 239 - KINDLING A FURNACE FIRE 241 - Sawdust Furnace 242 - PIPES AND PIPING 244 - Joints of Pipes and Fittings 248 - STEAM AND HOT WATER HEATING 251 - Points Relating to Steam Heating 254 - Ventilation 265 - Heating by Exhaust Steam 267 - Care of Steam Fittings 268 - Tools used in Steam Fitting 269 - Cocks 270 - Valves 271 - Steam Fittings 274 - Steam Pipe and Boiler Coverings 275 - Linear Expansion of Steam Pipes 276 - The Steam Loop 278 - BOILER MAKERS’ TOOLS AND MACHINERY 281 - STEAM 282 - WATER HAMMER 283 - HAZARDS OF THE BOILER ROOM 285 - Fuel Oil 289 - WATER CIRCULATION 294 - CHIMNEYS AND DRAUGHT 296 - PLUMBING 298 - Piping and Drainage 299 - Lead Pipe Joints 300 - Repairing Pipes with Putty Joints 303 - Bending Lead Pipe 304 - Plumber’s Solder 305 - Plumber’s Tools 306 - USEFUL TABLES OF WEIGHTS OF IRON AND - COMPARISONS OF GAUGES 309 - NOISELESS WATER HEATER 312 - ACCIDENTS AND EMERGENCIES 313 - Burns and Scalds 313 - Glue Burn Mixture 315 - Insensibility from Smoke 315 - Heat-stroke or Sun-stroke 316 - Cuts and Wounds 316 - Bleeding 317 - Frost Bite 318 - Broken Bones 318 - Poultices 319 - How to Carry an Injured Person 319 - PERSONAL 320 - INDEX 321 - ADVERTISMENTS 333 - - - - -INTRODUCTION. - - -Each successive generation of engineers has added certain _unwritten -experiences_ to the general stock of knowledge relating to steam -production, which have been communicated to their successors, and by -them added to, in their turn; it is within the province of this book to -put in form for reference, these unwritten laws of conduct, which have -passed into MAXIMS among engineers and firemen—a maxim being -an undisputed truth, expressed in the shortest terms. - - SOLILOQUY OF AN ENGINEER. “Standing in the boiler room and looking - around me, there are many things I ought to know a good deal - about. Coal! What is its quality? How much is used in ten hours or - twenty-four hours? Is the grate under the boiler the best for an - economical consumption of fuel? Can I, by a change in method of - firing, save any coal? The safety-valve. Do I know at what pressure - it will blow off? Can I calculate the safety-valve so as to be - certain the weight is placed right? Do I know how to calculate the - area of the grate, the heating surface of the tubes and shell? Do - I know the construction of the steam-gauge and vacuum-gauge? Am I - certain the steam-gauge is indicating correctly, neither over nor - under the pressure of the steam? What do I know about the setting - of boilers? About the size and quality of fire bricks? About the - combination of carbon and hydrogen of the fuel with the oxygen of the - atmosphere? About oxygen, hydrogen and nitrogen? About the laws of - combustion? About radiation and heat surfaces? - - “Do I know what are good non-conductors for covering of pipes, and - why they are good? Do I know how many gallons of water are in the - boiler? - - “What do I know about water and steam? How many gallons of water are - evaporated in twenty-four hours? What do I know about iron and steel, - boiler evaporation, horse power of engines, boiler appendages and - fittings. - - “Can I calculate the area and capacity of the engine cylinder? Can I - take an indicator diagram and read it? Can I set the eccentric? Can - I set valves? Do I understand the construction of the thermometer, - and know something about the pressure of the atmosphere, temperature - and the best means for ventilation? Can I use a pyrometer and a - salinometer? - - “Without going outside of my boiler and engine room I find these - things are all about me—air, water, steam, heat, gases, motion, - speed, strokes and revolutions, areas and capacities—how much do I - know about these? - - “How much can be learned from one lump of coal? What was it, where - did it come from? When it is burned, what gases will it give off? - - “And so with water. What is the composition of water? What are - the effects of heat upon it? How does it circulate? What is the - temperature of boiling water? What are the temperatures under - different pressures? What is latent heat? What is expansive force?” - -These are the questioning thoughts which fill, while on duty, more -or less vividly, the minds of both engineers and firemen, and it is -the purpose of this volume to answer the enquiries, as far as may -be without attempting too much; for the perfect knowledge of the -operations carried on within the boiler-room involves an acquaintance -with many branches of science. In matters relating to steam -engineering, it must be remembered that “art is long and time is short.” - -The utility of such a book as this is intended to be, no one will -question, and he who would not be a “hewer of wood and a drawer of -water” to the more intelligent and well-informed mechanic, must possess -to a considerable extent the principles and rules embraced in this -book; and more especially, if he would be master of his profession and -reputed as one whose skill and decisions can be implicitly relied upon. - -The author in the preparation of the work has had two objects -constantly in view; first to cause the student to become familiarly -acquainted with the leading principles of his profession as they -are mentioned, and secondly, to furnish him with as much advice and -information as possible within the reasonable limits of the work. - -While it is a fact that some of the matter contained in this work is -very simple, and all of it intended to be very plain, it yet remains -true that the most expert living engineer was at one time ignorant of -the least of the facts and principles here given, and at no time in -his active career can he ever get beyond the necessity of knowing the -primary steps by which he first achieved his success. - -The following taken from the editorial columns of the leading -mechanical journal of the country contains the same suggestive ideas -already indicated in the “soliloquy of an engineer:” - - “There is amongst engineers in this country a quiet educational - movement going on in matters relating to facts and principles - underlying their work that is likely to have an important influence - on industrial affairs. This educational movement is noticeable in - all classes of workmen, but amongst none more than among the men in - charge of the power plants of the country. It is fortunate that this - is so, for progress once begun in such matters is never likely to - stop. - - “Engineers comprise various grades from the chief engineer of some - large establishment, who is usually an accomplished mechanic, - carrying along grave responsibilities, to the mere stopper and - starter, who is engineer by courtesy only, and whose place is likely - to be soon filled by quite another man, so far as qualifications are - concerned. Men ignorant of everything except the mere mechanical - details of their work will soon have no place. - - “Scarcely a week passes that several questions are not asked by - engineers, either of which could be made the subject of a lengthy - article. This is of interest in that it shows that engineers, are not - at the present time behind in the way of seeking information. Out of - about a thousand questions that went into print, considerable more - than half were asked by stationary engineers. These questions embrace - many things in the way of steam engineering, steam engine management, - construction, etc.” - -The old meaning of the word lever was “a lifter” and this book is -intended to be to its attentive student, a real lever to advance him -in his life work; it is also to be used like a ladder, which is to be -ascended step by step, the lower rounds of which, are as important as -the highest. - -It is moreover, the earnest wish of the editor that when some, -perchance may have “climbed up” by the means of this, his work, they -may in their turn serve as lifters to advance others, and by that means -the benefits of the work widely extended. - - - - -MATERIALS. - - - _The things with which the engineer has to deal in that place where - steam is to be produced as an industrial agent, are_ - - _1. The Steam Generator._ - - _2. Air._ - - _3. Fuel._ - - _4. Water._ - - _5. Steam Appliances._ - - _Starting with these points which form a part of every steam plant, - however limited, however vast, the subject can easily be enlarged - until it embraces a thousand varied divisions extending through all - time and into every portion of the civilized world._ - - _It is within the scope of this work to so present the subjects - specified, that the student may classify and arrange the matter into - truly scientific order._ - - - - -MATERIALS. - - -In entering the steam department, where he is to be employed, the eye -of the beginner is greeted with the sight of coal, water, oil, etc., -and he is told of invisible materials, such as air, steam and gases; it -is the proper manipulation of these seen and unseen material products -as well as the machines, that is to become his life task. In aiding -to the proper accomplishment of the yet untried problems nothing can -be more useful than to know something of the nature and history of -the different forms of matter entering into the business of steam -production. Let us begin with - - -COAL. - -The source of all the power in the steam engine is stored up in coal in -the form of heat. - -And this heat becomes effective by burning it, that is, by its -combustion. - -Coal consists of carbon, hydrogen, nitrogen, sulphur, oxygen and ash. -These elements exist in all coals but in varying quantities. - -These are the common proportions of the best sorts: - - =========+============+============+===========+========+======== - | | | WOOD | | PEAT - | ANTHRACITE | BITUMINOUS | (AVERAGE) | PEAT | 1/4 - | | | DRY. | | WATER - ---------+------------+------------+-----------+--------+-------- - Carbon | 90-1/2 | 81 | 50 | 59 | 44 - Hydrogen | 2-1/2 | 5-1/4 | 6 | 6 | 4-1/2 - Nitrogen | 0-1/4 | 1 | 1 | 1-1/4 | 1 - Sulphur | 00 | 1-1/2 | 0 | ? | (25) - Oxygen | 2-1/2 | 6-1/2 | 41 | 30 | 22-1/2 - Ash | 4-1/4 | 4-3/4 | 2 | 3-3/4 | 3 - | ----- | ------ | ------ | ------ |-------- - | 100 | 100 | 100 | 100 | 100 - -In burning coal or other fuel atmospheric air must be introduced before -it will burn; the air furnishes the oxygen, without which combustion -cannot take place. - -It is found that in burning one lb. of coal one hundred and fifty cubic -feet of air must be used and in every day practice it is necessary to -supply twice as much; this is supplied to the coal partly through the -grate bars, partly through the perforated doors, and the different -devices for applying it already heated to the furnace. - - -WOOD. - -Wood as a combustible, is divisible into two classes: 1st, the hard, -compact and comparatively heavy, such as oak, ash, beech, elm. 2d, -the light colored soft, and comparatively light woods as pine, birch, -poplar. - -Wood when cut down contains nearly half moisture and when kept in a dry -place, for several years even, retains from 15 to 20 per cent. of it. - -The steam producing power of wood by tests has been found to be but -little over half that of coal _and the more water in it the less its -heating power_. In order to obtain the most heating power from wood it -is the practice in some works in Europe where fuel is costly, to dry -the wood fuel thoroughly, even using stoves for the purpose, before -using it. This “hint” may serve a good purpose on occasion. - -The composition of wood reduced to its elementary condition will be -found in the table with coal. - - -PEAT. - -Peat is the organic matter or vegetable soil of bogs, swamps and -marshes—decayed mosses, coarse grasses, etc. The peat next the -surface, less advanced in decomposition, is light, spongy and fibrous, -of a yellow or light reddish-brown color; lower down it is more -compact, of a darker-brown color, and in the lowest strata it is of a -blackish brown, or almost a black color, of a pitchy or unctuous feel. - -Peat in its natural condition generally contains from 75 to 80 per -cent. of water. It sometimes amounts to 85 or 90 per cent. in which -case the peat is of the consistency of mire. - -When wet peat is milled or ground so that the fibre is broken, crushed -or cut, the contraction in drying is much increased by this treatment; -and the peat becomes denser, and is better consolidated than when -it is dried as it is cut from the bog; peat so prepared is known as -_condensed_ peat, and the degree of condensation varies according to -the natural heaviness of the peat. So effectively is peat consolidated -and condensed by the simple process of breaking the fibres whilst wet, -that no merely mechanical force of compression is equal to it. - -In the table the elements of peat are presented in two conditions. One -perfectly dried into a powder before analyzing and the other with 25 -per cent. of moisture. - -The value of peat as a fuel of the future is an interesting problem in -view of the numerous inroads made upon our great natural coal fields. - - -TAN. - -Tan, or oak bark, after having been used in the process of tanning is -burned as fuel. The spent tan consists of the fibrous portion of the -bark. Five parts of oak bark produce four parts of dry tan. - - -STRAW. - -Two compositions of straw (as a fuel) is as follows: - - Water, 14 per cent. - Combustible matter, 79 „ - Ash, 7 „ - - -COKE, CHARCOAL, PEAT CHARCOAL. - -These are similar substances produced by like processes from coal, -wood, and peat and they vary in their steam-producing power according -to the power of the fuels from which they are produced. The method by -which they are made is termed carbonization, which means that all the -gases are removed by heat in closed vessels or heaps, leaving only the -carbon and the more solid parts like ashes. - - -LIQUID AND GAS FUELS. - -Under this head come petroleum and coal gas, which are obtained in -great variety and varying value from coal and coal oil. The heating -power of these fuels stands in the front rank, as will be seen by the -table annexed. - -There are kinds of fuel other than coal, such as wood, coke, sawdust, -tan bark, peat and petroleum oil and the refuse from oil. These are all -burned with atmospheric air of which the oxygen _combines_ with the -combustible part of the fuel while the nitrogen passes off into the -chimney as waste. - -The combustible parts of coal are carbon, hydrogen and sulphur and -the unburnable parts are nitrogen, water and the incombustible solid -matters such as ashes and cinder. In the operation of firing under a -boiler the three first elements are totally consumed and form heat; the -nitrogen, and water in the form of steam, escapes to the flue, and the -ashes and cinders fall under the grates. - -The anthracite coal retain their shape while burning, though if too -rapidly heated they fall to pieces. The flame is generally short, of a -blue color. The coal is ignited with difficulty; it yields an intense -local or concentrated heat; and the combustion generally becomes -extinct while yet a considerable quantity of the fuel remains on the -grate. - -The dry or free burning bituminous coals are rather lighter than -the anthracites, and they soon and easily arrive at the burning -temperature. They swell considerably in coking, and thus is facilitated -the access of air and the rapid and complete combustion of their fixed -carbon. - -The method of firing with different sorts of fuel will be treated -elsewhere. - - -AIR. - -The engineer’s success in the management of the furnace depends quite -as much upon his handling the air in the right mixtures and proportions -as it does in his using the fuel—for - -1. Although invisible to the eye air is as much _a material substance_ -as coal or stone. If there were an opening into the interior of the -earth which would permit the air to descend its density would increase -in the same manner at it diminishes in the opposite direction. At the -depth of about 34 miles it would be as dense as water, and at the depth -of 48 miles it would be as dense as quicksilver, and at the depth of -about 50 miles as dense as gold. - -2. Air is not only a substance, but _an impenetrable body_; as for -example: if we make a hollow cylinder, smooth and closed at the bottom, -and put a stopper or solid piston to it, no force will enable us to -bring it into contact with the bottom of the cylinder, unless we permit -the air within it to escape. - -3. Air is _a fluid_ which is proved by the great movability of its -parts, flowing in all directions in great hurricanes and in gentle -breezes; and also by the fact that a pressure or blow is propagated -through all parts and affects all parts alike. - -4. It is also an _elastic fluid_, thus when an inflated bladder is -compressed it immediately restores itself to its former situation; -indeed, since air when compressed restores itself or tends to restore -itself, with the same force as that with which it is compressed, it is -a perfectly elastic body. - -5. The weight of a column of air one square foot at the bottom is found -to be 2156 lbs. or very nearly 15 lbs. to the square inch, hence it is -common to state the pressure of the atmosphere as equal to 15 lbs. to -the square inch. - -_It follows from these five points that the engineer must consider air -as a positive, although unseen, factor with which his work is to be -accomplished._ - -What air is composed of is a very important item of knowledge. It -is made of a _mixture_ of two invisible gases whose minute and -inconceivably small atoms are mingled together like a parcel of marbles -and bullets—that is while together they do not lose any of their -distinctive qualities. The two gases are called nitrogen and oxygen, -and of 100 parts or volumes of air 79 parts are of nitrogen and 21 -parts of oxygen; but _by weight_ (for the oxygen is the heaviest) 77 of -nitrogen and 23 of oxygen. - -The oxygen is the part that furnishes the heat by uniting with the -coal—indeed without it the process of combustion would be impossible: -of the two gases the oxygen is burned in the furnace, more or less -imperfectly, and the nitrogen is wasted. - - -TABLE OF EVAPORATION. - -In order to arrive at the money value of the various fuels heretofore -described a method of composition has been arrived at which gives -very accurately their comparative worth. The rule is too advanced for -this elementary work, but the following results are plainly to be -understood, and will be found to be of value. - - Lbs. of Fuel. Temperature of Water 212° - Coal, 14.62 lbs of Water. - Coke, 14.02 „ - Wood, 8.07 „ - Wood; 25% of water, 6.05 „ - Wood Charcoal, 13.13 „ - Peat, perfectly dry, 10.30 „ - Peat, with 25% moisture, 7.41 „ - Peat, Charcoal (dry), 12.76 „ - Tan, dry, 6.31 „ - Tan, 30% moisture, 4.44 „ - Petroleum, 20.33 „ - Coal gas 1 lb. or (31-1/3 cub. feet) 47.51 „ - -The way to read this table is as follows: “one lb. coal has an average -evaporative capacity of 14.62 lbs. of water,” or - -One lb. of peat with one-quarter moisture will evaporate, if _all_ the -heat is utilized 7.41 lbs. of water. - -In practice but little over half of these results are attained, but for -a matter of comparison of the value of one kind of fuel with another -the figures are of great value; a boiler burning wood or tan needs to -be much larger than one burning petroleum oil. - - -FIRE IRONS. - -The making or production of steam requires the handling of the fuel, -more or less, until its destruction is complete, leaving nothing behind -in the boiler room, except ashes and clinkers. The principal tools used -by the attendant, to do the task most efficiently are: 1. The scoop -shovel. 2. The poker. 3. The slice bar. 4. The barrow. - -[Illustration: Fig. 1.] - -Fig. 1. represents the regular scoop shovel commonly called “a coal -shovel,” but among railroad men and others, known as a locomotive or -charging scoop. The cut also represents a regular shovel. Both these -are necessary for the ordinary business of the boiler room. - -[Illustration: Fig. 2.] - -In cut 2 are represented a furnace poker, A, and two forms of the slice -bar. They are all made by blacksmiths from round iron, some 7 or 8 -feet long and only vary in the form of the end. The regular slice bar -is shown in C, Fig. 2; and “the dart” a special form used largely on -locomotives is shown in B. - -The dexterous use of these important implements can merely be indicated -in print, as it is part of the trade which is imparted by oral -instruction. One “point” in making the slice bar may be mentioned to -advantage—the lower side should be perfectly flat _so that it may -slide_ on the surface of the grate bars as it is forced beneath the -fire—and the upper portion of the edge should be in the shape of a half -wedge, so as to crowd upwards the ashes and clinkers while the lower -portion slides along. - -There is sometimes used in connection with these tools an appliance -called a LAZY BAR. This is very useful for the fireman when cleaning a -bituminous or other coal fire: it saves both time and fuel as well as -steam. It is a hook shaped iron, ingeniously attached above the furnace -door, so that it supports the principal part of the weight of the heavy -slice bar or poker when being used in cleaning out the fires. - -[Illustration: Fig. 3.] - -Equally necessary to the work of the boiler-room is the barrow shown in -cut. There are many styles of the vehicle denominated respectively—the -railroad barrow, the ore and stone barrow, the dirt barrow, etc.; but -the one represented in fig. 3 is the regular coal barrow. - -In conveying coal to “batteries” of boilers, in gas houses and other -suitable situations the portable car and iron track are nearly always -used instead of the barrow. In feeding furnaces with saw dust and -shavings large iron screw conveyors are frequently employed, as well -as blowers—In the handling of the immense quantities of fuel required, -the real ingenuity of the engineer in charge has ample opportunity for -exercise. - -There are also used in nearly all boiler rooms HOES made of heavy plate -iron, with handles similar to those shown in the cuts representing the -slice bar and poker. A set of two to four hoes of various sizes is a -very convenient addition to the list of fire tools; a light garden hoe -for handling ashes is not to be omitted as a labor saving tool. - - -HANDY TOOLS. - -Besides the foregoing devices for conducting the preliminary process -of the steam generation, the attendant should have close at hand a -servicable HAND HAMMER, a SLEDGE for breaking coal and similar work, -and A SCREW WRENCH and also a light LADDER for use about the boiler and -shafting. - -In addition to these there are various other things almost essential -for the proper doing of the work of the boiler room,—FIRE AND WATER -PAILS, LANTERNS, RUBBER HOSE, etc., which every wise steam user will -provide of the best quality and which the engineer will as carefully -keep in their appointed places ready for instant service. - -[Illustration: Fig. 4.] - -To these familiar tools can be added FILES, LACE CUTTERS, BOILER-FLUE -BRUSHES, STOCK and DIES, PIPE-TONGS, SCREW JACKS, VISES, etc., all of -which when used with skill and upon right occasion pay a large return -on their cost. - - -THE TOOL BOX. - -The complex operations of the boiler room, its emergencies and varying -conditions demand the use of many implements which might at first -thought be out of place. The following illustrations exhibit some of -these conveniences. - -[Illustration: Fig. 5.] - -Fig. 5, letter A, show the common form of COMPASSES which are -made from 3 to 8 inches long. Letter B, illustrates the common steel -compass dividers, which are made from 5 to 24 inches in length. - -[Illustration: Fig. 6.] - -In this illustration, A exhibits double, inside and outside -CALIPERS; B, adjustable outside Calipers; C, inside; and D -outside, plain calipers. - -[Illustration: Various Tools.] - - - - -THE FIRING OF STEAM BOILERS. - - -The care and management of a steam boiler comprises three things: - -1. The preparation, which includes the partial filling with water and -the kindling of the fire. - -2. The running, embracing the feeding, firing and extinction or banking -of the fire. - -3. The cleaning out after it has been worked for some time. - -To do this to the best advantage, alike to owner and employee, can be -learned only by practice under the tuition of an experienced person. -The “trick” or unwritten science of the duties of the skillful fireman -must be communicated to the beginner, by already experienced engineers -or firemen or from experts who have made the matter a special study. -_Let it be understood that the art of firing cannot be self taught._ - -The importance of this knowledge is illustrated by a remarkable -difference shown in competitive tests in Germany between trained and -untrained firemen in the matter of securing a high evaporation per -pound of coal. The trained men succeeded in evaporating 11 lbs. of -water, as against 6.89 lbs. which was the best that the untrained men -could obtain. - -It is certain that a poor fireman is a dear man at any price, and that -a competent one may be cheap at twice the wages now paid. Suppose, -for instance, a man who burns three tons a day is paid $2.00 for such -service, and that in so doing he is wasting as little as 10 per cent. -If the coal cost $4.50 per ton the loss will be $1.35 per day, or what -is equivalent to paying a man $3.35 per day who can save this amount. - -The late Chief Engineer of Philadelphia Water Works effected an annual -saving to the city of something like $50,000; and recently the weekly -consumption of a well established woolen mill was reduced from 71 to 49 -tons, a clear saving of 22 tons by careful attention to this point. - -It is apparent that any rules or directions which might be given for -one system would not apply equally to other forms of boilers and this -may be the principal reason that the art is one so largely of personal -instruction. Some rules and hints will, however, be given to the -beginner, which may prove of advantage in fitting the fireman for an -advanced position; or to assure him permanence in his present one. - -_No two boilers alike._ It is said that no two boilers, even though -they seemed to be exactly alike—absolute duplicates—ever did the same, -or equal service. Every steam boiler, like every steam engine, has an -individuality of its own, with which the person in charge has to become -acquainted, in order to obtain the best results from it. - -The unlikeness in the required care of steam engines which seem to -be exactly the same, is still more marked in the different skill -and experience demanded in handling locomotive, marine, stationary, -portable boilers and other forms of steam generators. - -BEFORE LIGHTING THE FIRE under the boiler in the morning, the engineer -or fireman should make a rapid yet diligent examination of various -things, viz.: 1. He should make sure that the boiler has the right -quantity of water in it—that it has not run out during the night or -been tampered with by some outside party; very many boilers have been -ruined by neglecting this first simple precaution. 2. He should see -that the safety-valve is in working order; this is done by lifting by -rod or hand the valve which holds the weight upon the safety valve rod. -3. He should open the upper gauge-cock to let out the air from the -boiler while the steam is forming. 4. He should examine the condition -of the grate-bars and see that no clinkers and but few ashes are left -from last night’s firing. 5. And finally, after seeing that everything -is in good shape, proceed to build the fire as follows: - -ON LIGHTING THE FIRE. When quite certain that everything is in good -condition, put a good armful of shavings or fine wood upon the grate, -then upon this some larger pieces of wood to form a bed of coals, and -then a little of the fuel that is to be used while running. Sometimes -it is better to light before putting on the regular fuel, but in any -case give it plenty of air. Close the fire doors, and open the ash pit, -giving the chimney full draught. - -When the fire is well ignited, throw in some of the regular fuel, and -when this is burning add more, a little at a time, and continue until -the fire is in its normal condition, taking care, however, not to let -it burn too freely for fear of injury to the sheets by a too rapid -heating. - -It is usually more convenient to light the fire through the fire door, -but where this cannot be done, a torch may be used beneath the grates, -or even a light fire of shavings may be kindled in the ash pit. - -At the time of lighting, all the draughts should be wide open. - -As soon as the steam is _seen_ to issue from the open upper gauge-cock -it is proof that the air is out. It should now be closed and the steam -gauge will soon indicate a rise in temperature. - -When the steam begins to rise it should next be observed that: 1. All -the cocks and valves are in working order—that they move easily. 2. -That all the joints and packings are tight. - -In the following two cuts are exhibited in an impressive way the -difference between proper and improper firing. - -[Illustration: Fig. 1.] - -Fig. 1 represents the proper mode of keeping an even depth of coal on -the grate bars; the result of which will be, a uniform generation of -gas throughout the charge, and a uniform temperature in the flues. - -[Illustration: Fig. 2.] - -Fig. 2 represents a very frequent method of feeding furnaces; charging -the front half as high, and as near the door, as possible, leaving the -bridge end comparatively bare. The result necessarily is that more -air obtains access through the uncovered bars than is required, which -causes imperfect combustion and consequent waste. - -The duties of the fireman in the routine of the day may thus be summed -up: - -1st.—_Begin to charge the furnace at the bridge end and keep firing to -within a few inches of the dead plate._ - -2d.—_Never allow the fire to be so low before a fresh charge is thrown -in, that there shall not be at least three to five inches deep of -clean, incandescent fuel on the bars, and equally spread over the -whole._ - -3d.—_Keep the bars constantly and equally covered_, particularly at the -sides and the bridge end, where the fuel burns away most rapidly. - -4th.—If the fuel burns unequally or into holes, _it must be leveled, -and the vacant spaces must be filled_. - -5th.—The large coals must be broken into pieces not bigger than a man’s -fist. - -6th.—When the ash pit is shallow, it must be the more frequently -cleared out. A body of hot cinders, beneath them, overheats and burns -the bars. - -7th.—The fire must not be hurried too much, but should be left to -increase in intensity gradually. When fired properly the fuel is -consumed in the best possible way, no more being burned than is needed -for producing a sufficient quantity of steam and keeping the steam -pressure even. - - -DIRECTIONS FOR FIRING WITH VARIOUS FUELS. - -FIRING BOILERS NEWLY SET, ETC.—Boilers newly set should be heated up -very slowly indeed, and the fires should not be lighted under the -boilers for at least two weeks after setting, if it is possible to wait -this length of time. This two weeks enables all parts of the mason work -to set gradually and harden naturally; the walls will be much more -likely to remain perfect than when fires are lighted while the mortar -is yet green. - -When fire is started under a new boiler the first time, it should -be a very small one, and no attempt should be made to do more than -moderately warm all parts of the brick work. A slow fire should be kept -up for twenty-four hours, and on the second day it may be slightly -increased. Three full days should elapse before the boiler is allowed -to make any steam at all. - -When the pressure rises, it should not be allowed to go above four or -five pounds, and the safety valve weight should be taken off to prevent -any possibility of an increase. Steam should be allowed to go through -all the pipes attached for steam, and blow through the engine before -any attempt is made to get pressure on them. The object of all these -precautions and this care is to prevent injury by sudden expansion, -which may cause great damage. - - -FIRING WITH COKE. - -Coke, in order to be completely consumed, needs a greater volume of -air per pound of fuel than coal. Theoretically it needs from 9 to 10 -lbs. of air to burn a pound of coal, and 12 to 13 lbs. of air to burn a -pound of coke. - -Coke, therefore, requires a more energetic draft, which is increased by -the fact that it can only burn economically in a thick bed. It is also -necessary to take into account the size of the pieces. - -The ratio between the heating and grate surface should be less with -coke than with coal; that is to say, the grate should be larger. - -The difference amounts to about 33 per cent. In fact, about 9-3/4 lbs. -of coke should be burned per hour on each square foot of grate area, -while at least 14-1/2 lbs. of coal can be burned upon the same space. - -The high initial temperature which is developed by the combustion of -coke requires conducting walls. Therefore the furnace should not be -entirely surrounded by masonry; and the plates of the boiler should -form at least the crown of the fire-box. In externally fired boilers, -the furnace should be located beneath and not in front of the boiler. -Internal fire-boxes may be used, but the greatest care should be -exercised to avoid any incrustation of the plates, and in order that -this may be done, only the simplest forms of boilers should be used. -With coke it is not essential that long passages should be provided for -the passage of the products of combustion, since the greater part of -the heat developed is transmitted to the sheets in the neighborhood of -the furnace. - -Since coke contains very little hydrogen, the quick flaming combustion -which characterizes coal is not produced, but the fire is more even and -regular. And, finally, the combustion of coal is distinguished by the -fact that in the earlier phases there is usually an insufficiency of -air, while in the last there is no excess. - -The advantage of coke over raw soft coal as a fuel is that otherwise -useless slack can be made available by admixture in its manufacture, -and especially that it can be perfectly and smokelessly burnt without -the need of skilled labor. And we cannot doubt that the public demand -for a clear and healthy atmosphere will finally result in the almost -complete substitution of coke fuel for soft lump coal. - -SIXTEEN STEAM BOILERS in a large mill in Massachusetts of 54 and 60 -inches in diameter are fired as follows: - -There are three separate batteries; one of five boilers, one of eight -and one of three. Each boiler is fired every five minutes. There are -two firemen for the battery of twelve and one for each of the others. -A gong in each fire-room is operated by electricity in connection with -a clock. The duty of the fireman is this, that when the gong strikes he -commences at one end of his fire-room and fires as rapidly as possible, -opening one-half of each furnace door. The coal is thrown only on -one-half of the grate space as he rapidly fires each boiler, the -other half is covered at the next sounding of the gong. The old style -of straight grate is used. The fires are kept six inches thick or a -little thicker. No slicing is done. It is, of course, to be understood -that the firemen arrange the quantity of coal fired according to the -apparent necessity of the case. Bituminous coal is used, and it is -broken into small pieces, so as to distribute well. Accurate account -is kept of the quantity of coal used and the engines are frequently -indicated. - -TWENTY HORSE POWER.—An old engineer says the way he handled his boiler -of this size, burning 800 lbs. of screenings per day, is as follows: - -My method is to run as heavy a fire as my fire-box will allow to be -kept under the bridge wall, and not to disturb it more than once in a -ten-hours run, then clean out with care and as speedily as possible, -dress light and let it come up and get ready to bank. In banking I make -sure to have an even fire, as deep as the bridge wall will allow. Then -I shut my dampers and let it lie. In the morning I open and govern by -the dampers. I do not touch my fire until 3.30 or 4 o’clock in the -afternoon, and then proceed to clean as before. - - -FIRING WITH COAL TAR.—The question of firing retort benches with tar -instead of coke has engaged the attention of gas managers for many -years, and various modes have been adopted for its management. The -chief difficulty has been in getting a constant flow of tar into the -furnace, uninterrupted by stoppages caused by the regulating cock or -other appliance not answering its purpose and by the carbonizing of -the tar in the delivery pipe, thus choking it up and rendering it -uncertain in action. To obviate these difficulties various plans have -been resorted to, but the best means for overcoming them are thus -described; fix the tar supply tank as near the furnace to be supplied -as convenient, and one foot higher than the tar-injector inlet. A cock -is screwed into the side of the tank, to which is attached a piece -of composition pipe 3/8-inch in diameter, ten inches long. To this a -1/2-inch iron service pipe is connected, the other end of which is -joined to the injector. By these means it is found that at the ordinary -temperature of the tar well (cold weather excepted) four gallons of -tar per hour are delivered in a constant steam into the furnace. If -more tar is required, the piece of 3/8-inch tube must be shortened, -or a larger tube substituted, and if less tar is required it must -be lengthened. The risk of stoppage in the nozzle of the injector -is overcome by the steam jet, which scatters the tar into spray and -thus keeps everything clear. Trouble being occasioned by the retorts -becoming too hot, in which case, on shutting off the flow of tar -for a while, the tar in the pipe carbonized and caused a stoppage, -a removable plug injector is fitted and ground in like the plug of -a cock, having inlets on either side for tar and steam. This plug -injector can be removed, the tar stopped in two seconds and refixed in -a similar time. The shell of the injector is firmly bolted to the top -part of the door frame. The door is swung horizontally, having a rack -in the form of a quadrant, by which it is regulated to any required -height, and to admit any quantity of air. - - -FIRING WITH STRAW.—The operation of burning straw under a boiler -consists in the fuel being fed into the furnace only as fast as needed. -When the straw is handled right, it makes a beautiful and very hot -flame and no smoke is seen coming from the stack. The whole secret -of getting the best results from this fuel is to feed it into the -furnace in a gradual stream as fast as consumed. When this is done -complete combustion is the result. A little hole maybe drilled in the -smoke-box door, so that the color of the fire can be seen and fire is -handled accordingly. When the smoke comes from the stack the color of -the flame is that of a good gas jet. By feeding a little faster the -color becomes darker and a little smoke comes from the stack; feeding a -little faster the flame gets quite dark and the smoke blacker; faster -still, the flame is extinguished, clouds of black smoke come from the -stack, and the pressure is falling rapidly. - - -FIRING WITH OIL.—Great interest is now manifested in the use of oil as -fuel. There are various devices used for this purpose, most of them -depending upon a steam jet to atomize the oil, or a system of retorts -to first heat the oil and convert it into gas, before being burned. - -Another method in successful operation is the use of compressed air -for atomizing the oil—air being the element nature provides for the -complete combustion of all matter. The cleanliness of the latter system -and its comparative freedom from any odor of oil or gas and its perfect -combustion, all recommend it. Among the advantages claimed for the use -of oil over coal are 1, uniform heat; 2, constant pressure of steam; -3, no ashes, clinkers, soot or smoke, and consequently clean flues; 4, -uniform distribution of heat and therefore less strain upon the plates. - - -FIRING ON AN OCEAN STEAMER like the “_Umbria_.”—The men come on in -gangs of eighteen stokers or firemen and twelve coal passers, and -the “watch” lasts four hours. The “_Umbria_” has 72 furnaces, which -require nearly 350 tons of coal a day, at a cost of almost $20,000 per -voyage. One hundred and four men are employed to man the furnaces, and -they have enough to do. They include the chief engineer, his three -assistants, and ninety stokers and coal passers. - -The stoker comes to work wearing only a thin undershirt, light trousers -and wooden shoes. On the “_Umbria_” each stoker tends four furnaces. -He first rakes open the furnaces, tosses in the coal, and then cleans -the fire; that is, pries the coal apart with a heavy iron bar, in order -that the fire may burn freely. He rushes from one furnace to another, -spending perhaps two or three minutes at each. Then he dashes to the -air pipe, takes his turn at cooling off, and waits for another call -to his furnace, which comes speedily. When the “watch” is over, the -men schuffle off, dripping with sweat from head to foot, through long, -cold galleries to the forecastle, where they turn in for eight hours. -Four hours of scorching and eight hours sleep make up the routine of a -fireman’s life on a voyage. - -The temperature is ordinarily 120°, but sometimes reaches 160°; and the -work is then terribly hard. The space between the furnaces is so narrow -that when the men throw in coal they must take care when they swing -back their shovels, lest they throw their arms on the furnace back of -them. - -In a recent trial of a government steamer the men worked willingly -in a temperature of 175°, which, however, rose to 212° or the heat -of boiling water. The shifts of four hours were reduced to 2 hours -each, but after sixteen men had been prostrated, the whole force of -thirty-six men refused to submit to the heat any longer and the trial -was abandoned. - -There is no place on ocean or land where more suffering is inflicted -and endured by human beings than in these h——holes, quite properly so -called; it is to be hoped that the efforts towards reform in the matter -will not cease until completely successful. - - -FIRING OF SAWDUST AND SHAVINGS.—“The air was forced into the furnace -with the planer shavings at a velocity of about 12 feet per second, and -at an average temperature of about 60 degrees Fahrenheit. The shavings -were forced through a pipe 12 inches in diameter, above grate, into the -combustion chamber. The pipe had a blast gate to regulate the air in -order to maintain a pressure in the furnace, which a little more than -balanced the ascending gases in the funnel or chimney. All the fireman -had to do was to keep the furnace doors closed and watch the water in -the gauges of his boiler. The combustion in the furnace was complete, -as no smoke was visible. The shavings were forced into the combustion -chamber in a spray-like manner, and were caught into a blaze the moment -they entered. The oxygen of the air so forced into the furnace along -with the shavings gave full support to the combustion. The amount of -shavings consumed by being thus forced into the furnace was about fifty -per cent. less than the amount consumed when the fireman had to throw -them in with his shovel.” - -[Illustration: Fig. 9.] - -It is an important “point” when burning shavings or sawdust with a -blast, to keep the blower going without cessation, as there have been -disastrous accidents caused by the flames going up the shutes, thence -through the small dust tubes leading from the bin to the various -machines. - -[Illustration: Fig. 10.] - -In firing “shavings” by hand it is necessary to burn them from the top -as otherwise the fire and heat are only produced when all the shavings -are charred. To do this, provide a half-inch gas pipe, to be used as a -light poker; light the shaving fire, and when nearly burned take the -half-inch pipe and divide the burning shavings through the middle, -banking them against the side-walls, as shown in Fig. 9. Now feed a -pile of new shavings into the centre on the clean grate bars, as shown -in Fig. 10, and close the furnace doors. The shavings will begin to -burn from above, lighted from the two side fires, the air will pass -through the bars into the shavings, where it will be heated and unite -with the gas, making the combustion perfect, generating heat, and no -smoke, and the fire will last much longer and require not half the -labor in stoking. - - -FIRING A LOCOMOTIVE. - -[Illustration] - -This figure exhibits the interior of the furnace of a locomotive -engine, which varies greatly from the furnace of either a land or -marine boiler. This difference is largely caused by the method of -applying the draught for the air supply; in the locomotive this is -effected by conducting the exhaust steam through pipes from the -cylinders to the smoke-box and allowing it to escape up the smoke -stack from apertures called exhaust nozzles; the velocity of the steam -produces a vacuum, by which the products of combustion are drawn into -the smoke-box with great power and forced out of the smoke stack into -the open air. - -To prevent the too quick passage of the gases into the flues an -appliance called a fire brick arch has been adopted and has proved very -efficient. In order to be self supporting it is built in the form of -an arch, supported by the two sides of the fire box which serve for -abutments. The arch has been sometimes replaced by a hollow riveted -arrangement called a water table designed to increase the fire surface -of the boiler. - - -FIRING A LOCOMOTIVE.—No rules can possibly be given for firing a -locomotive which would not be more misleading than helpful. This is -owing to the great variations which exist in the circumstances of the -use of the machine, as well as the differences which exist in the -various types of the locomotive. - -These variations may be alluded to, but not wholly described. 1. They -consist of the sorts of fuel used in different sections of the country -and frequently on different ends of the same railroad; hard coal, soft -coal, and wood all require different management in the furnace. 2. The -speed and weight of the train, the varying number of cars and frequency -of stopping places, all influence the duties of the fireman and tax -his skill. 3. The temperature of the air, whether cold or warm, dry -weather or rain, and night time and day time each taxes the skill of -the fireman. - -Hence, to be an experienced fireman in one section of the country and -under certain circumstances does not warrant the assurance of success -under other conditions and in another location. The subject requires -constant study and operation among not only “new men” but those longest -in the service. - -More than in any other case to be recalled, must the fireman of a -locomotive depend upon the personal instruction of the engineer in -charge of the locomotive. - - -FIRING WITH TAN BARK.—Tan bark can be burned upon common grates and -in the ordinary furnace by a mixture of bituminous screenings. One -shovel full of screenings to four or five of bark will produce a more -economical result than the tan bark separate, as the coal gives body -to the fire and forms a hot clinker bed upon which the bark may rest -without falling through the spaces in the grate bars, and with the -coal, more air can be introduced to the furnace. - -The above relates to common furnaces, but special fire boxes have -been recently put into operation, fed by power appliances, which work -admirably. The “point” principally to be noted as to the efficacy of -tan bark as a fuel, is to the effect, that like peat, the drier it is -the more valuable is it as a fuel. - - -POINTS RELATING TO FIRING. - -THE PROCESS OF BOILING. Let it be remembered that the boiling spoken -of so often is really caused by the formation of the steam particles, -and that without the boiling there can be but a very slight quantity of -steam produced. - -While pure water boils at 212°, if it is saturated with common salt, -it boils only on attaining 224°, alum boils at 220°, sal ammoniac at -236°, acetate of soda at 256°, pure nitric acid boils at 248°, and pure -sulphuric acid at 620°. - -ON THE FIRST APPLICATION OF HEAT to water small bubbles soon begin to -form and rise to the surface; these consist of air, which all water -contains dissolved in it. When it reaches the boiling point the bubbles -that rise in it are principally steam. - -IN THE CASE OF A NEW PLANT, or where the boiler has some time been -idle it is frequently advisable to build a small fire in the base of -the chimney before starting the boiler fires. This will serve to heat -the chimney and drive out any moisture that may have collected in the -interior and will frequently prevent the disagreeable smoking that -often follows the building of a fire in the furnace. - -ALWAYS BEAR IN MIND that the steam in the boilers and engines is -pressing outward on the walls that confine it in every direction; and -that the enormous forces you are handling, warn you to be careful. - -When starting fires close the gauge cocks and safety valve as soon as -steam begins to form. - -GO SLOW. It is necessary to start all new boilers very slowly. The -change from hot to cold is an immense one in its effects on the -contraction and expansion of the boiler, the change of dimension -by expansion is a force of the greatest magnitude and cannot be -over-estimated. Leaks which start in boilers that were well made and -perfectly tight can be attributed to this cause. Something must give -if fires are driven on the start, and this entails trouble and expense -that there is no occasion for. This custom applies to engines and steam -pipes as well as to boilers. No one of any experience will open a stop -valve and let a full head of live steam into a cold line of pipe or a -cold engine. - -To preserve the grate bars from excessive heat, when first firing a -boiler, it is well to sprinkle a thin layer of coal upon the grates -before putting in the shavings and wood for starting the fire. This -practice tends greatly to prolong the life of the grate-bars. - -The fuel should generally be dry when used. Hard coal, however, may be -dampened a little to good advantage, as it is then less liable to crowd -and will burn more freely. - -Air, high temperature and sufficient time are the principal points in -firing a steam boiler. - -In first firing up make sure that the throttle valve is closed, in -order that the steam first formed may not pass over into the engine -cylinder and fill it with water of condensation. If the throttle valve -leak steam it should be repaired at the first opportunity. - -Keep all heating surfaces free from soot and ashes. - -Radiant rays go in all directions, yet they act in the most efficient -manner when striking a surface exactly at a right angle to their -line of movement. The sides of a fire-box are for that reason not -as efficient as the surface over the fire, and a flat surface over -the fire is the best that can be had, so far as that fact alone is -concerned. - -When combustion is completed in a furnace, then the balance of the -boiler beyond the bridge wall can be utilized for taking up heat -from the gases. The most of this heat has to be absorbed by actual -contact; thus by the tubes the gases are finally divided, allowing that -necessary contact. - -Combustion should be completed on the grates for the reason that -it can be effected there at the highest temperature. When this is -accomplished, the fullest benefit is had from radiant heat striking the -bottom of the boiler—_it is just there that the bulk of the work is -done_. - -There must necessarily be some waste of heat by its passing up the -chimney to maintain draft. It is well to have the gases, as they enter -the chimney, as much below 600 deg. F. (down to near the temperature of -the steam) as you can and yet maintain perfect combustion. - -Every steam engine has certain well-defined sounds in action which we -call noises, for want of a better term, and it is upon them and their -continuance that an engineer depends for assurance that all is going -well. - -This remark also applies to the steam boiler, which has, so to speak, -a language of its own, varying in volume from the slight whisper which -announces a leaking joint to the thunder burst which terribly follows a -destructive explosion. The hoarse note of the safety-valve is none the -less significant because common. - -The dampers and doors to the furnace and ash-pit should always be -closed after the fire has been drawn, in order to keep the heat of the -boiler as long as possible. - -But the damper must never be entirely closed while there is fire on the -grate, as explosions dangerous in their character might occur in the -furnace from the accumulated gases. - -Flues or tubes should often be swept, as soot, in addition to its -liability to becoming charged with a corroding acid, is a non-conductor -of heat, and the short time spent in cleaning them will be repaid by -the saving of labor in keeping up steam. In an establishment where they -used but half a ton of bituminous coal per day, the time of raising -steam in the morning was fifty per cent. longer when the tubes were -unswept for one week than when they were swept three times a week. - -SMOKE will not be seen _if combustion is perfect_. Good firing will -abate most of the smoke. - -Coals, at the highest furnace temperature, radiate much heat, whereas -gases ignited at and beyond the bridge wall radiate comparatively -little heat—it is a law in nature for a solid body highly heated to -radiate heat to another solid body. - -DRY AND CLEAN is the condition in which the boiler should be kept, -_i.e._, dry outside and clean both inside and out. - -To haul his furnace fire and open the safety valve before seeking his -own safety or the preservation of property, is the duty of the fireman -in the event of fire threatening to burn a whole establishment. - -Many, now prominent, engineers have made their first reputation by -remembering to do this at a critical time. - -WHEN WATER IS PUMPED into the boiler or allowed to run in, some opening -must be given for the escape of the contained air; usually the most -convenient way is to open the upper gauge cock after the fire has been -lighted until cloudy steam begins to escape. - -In a summary of experiments made in England, it is stated that:— - -“A moderately thick and hot fire with rapid draft uniformly gave the -best results. - -“Combustion of black smoke by additional air was a loss. - -“In all experiments the highest result was always obtained when all the -air was introduced through the fire bars. - -“Difference in mode of firing only may produce a difference of 13 per -cent. (in economy).” - -The thickness of the fire under the boiler should be in accordance with -the quality and size of the fuel. For hard coal the fire should be as -thin as possible, from three to six inches deep; when soft coal is -used, the fire should be thicker, from five to eight inches deep. - -If it is required to burn coal dust without any change of grates, -wetting the coal is of advantage; not that it increases its heat power, -but because it keeps it from falling through the grates or going up the -chimneys. The same is true of burning shavings; by watering they are -held in the furnace, and the firing is done more easily and with better -results. - -STIRRING THE FIRE should be avoided as much as possible; firing should -be performed evenly and regularly, a little at a time, as it causes -waste fuel to disturb the combustion and by making the fuel fall -through the grates into the ash pit; hence do not “clean” fires oftener -than absolutely necessary. - -The slower the velocity of the gases before they pass the damper, the -more nearly can they be brought down to the temperature of the steam, -hence with a high chimney and strong draft the dampers should be kept -nearly closed, if the boiler capacity will permit it. - -No arbitrary rule can be laid down for keeping fires thick or thin. -Under some conditions a thin fire is the best, under others a thick -fire gives best economy. This rule, however, governs either case: you -must have so active a fire as to give strong radiant heat. - -One of the highest aims of an expert fireman should be to keep the -largest possible portion of his grate area in a condition to give great -radiant heat the largest possible part of the day—using anthracite coal -by firing light, quick and often, not covering all of the incandescent -coals. Using bituminous coal, hand firing, by coking it _very near_ the -dead plate, allowing some air to go through openings in the door, and -by pushing toward the bridge wall only live coals—when slicing, to open -the door only far enough to work the bar; this is done with great skill -in some cases. - -REGULATING THE DRAFT.—This should be done so as to admit _the exact -quantity of air_ into the furnace, neither too much nor too little. -It should be remembered that fuel cannot be burned without air and if -too much air is admitted it cools the furnace and checks combustion. -It is a good plan to decrease the draft when firing or cleaning out, -by partly closing the damper or shutting off the air usually admitted -from below the grates; this is to have just draft enough to prevent the -flame from rushing out when the door is opened. - -_By luminous flame_ is generally meant that which burns with a bright -yellow to white color. All flame under a boiler is not luminous, -sometimes the whole or a part of it will be red or blue. The more -luminous the flame, that is to say, the nearer white it is, the better -combustion. - -TO DETERMINE THE TEMPERATURE OF A FURNACE FIRE the following table is -of use. The colors are to be observed and the corresponding degrees of -heat will be approximately as follows: - - Faint red 960° F. - Bright red 1,300° F. - Cherry red 1,600° F. - Dull orange 2,000° F. - Bright orange 2,100° F. - White heat 2,400° F. - Brilliant white heat 2,700° F. - -That is to say, when the furnace is at a “white heat” the heat equals -2,400 degrees Fahrenheit, etc. - -Another method of finding the furnace heat is by submitting a small -portion of a particular metal to the heat. - - Tin melts at 442° F. - Lead „ „ 617° F. - Zinc „ „ 700° F. nearly. - Antimony melts at 810 to 1,150° F. - Silver melts at 1,832 to 1,873° F. - Cast Iron melts at 2,000° F. nearly. - Steel „ „ 2,500° F. „ - Wrought Iron melts at 2,700° F. „ - Hammered Iron melts at 2,900° F. „ - - -FOAMING IN BOILERS. - -The causes are—dirty water, trying to evaporate more water than the -size and construction of the boiler is intended for, taking the steam -too low down, insufficient steam room, imperfect construction of -boiler, too small a steam pipe and sometimes it is produced by carrying -the water line too high. - -Too little attention is paid to boilers with regard to their -evaporating power. Where the boiler is large enough for the water to -circulate, and there is surface enough to give off the steam, foaming -never occurs. - -As the particles of the steam have to escape to the surface of the -water in the boiler, unless that is in proportion to the amount of -steam to be generated, it will be delivered with such violence that the -water will be mixed with it, and cause foaming. - -For violent ebullition a plate hung over the hole where the steam -enters the dome from the boiler, is a good thing, and prevents a rush -of water by breaking it, when the throttle is opened suddenly. - -In cases of very violent foaming it is imperative to check the draft -and cover the fires. - -The steam pipe may be carried through the flange six inches into the -dome—which will prevent the water from entering the pipes by following -the sides of the dome as it does. - -A similar case of priming of the boilers of the U. S. Steamer Galena -was stopped by removing some of the tubes under the smoke stack and -substituting bolts. - -Clean water, plenty of surface, plenty of steam room, large steam -pipes, boilers large enough to generate steam without forcing the -fires, are all that is required to prevent foaming. - -A high pressure insures tranquillity at the surface, and the steam -itself being more dense it comes away in a more compact form, and the -ebullition at the surface is no greater than at a lower pressure. When -a boiler foams it is best usually to close the throttle to check the -flow, and that keeps up the pressure and lessens the sudden delivery. - -Too many flues in a boiler obstruct the passage of the steam from the -lower part of the boiler on its way to the surface—this is a fault in -construction. - -An engineer who had been troubled with priming, finally removed 36 of -the tubes in the centre of the boiler, so as to centralize the heating -effect of the fire, thereby increasing the rapidity of ebullition at -the centre, while reducing it at the circumference. The effect of the -change was very marked. The priming disappeared at once. The water line -became nearly constant, the extreme variation being reduced to two -inches. - - - - -A CHAPTER OF DON’TS. - - -_Which is another way of repeating what has already been said._ - - 1. =_Don’t_= empty the boiler when the brick work is hot. - - 2. =_Don’t_= pump cold water into a hot boiler. - - 3. =_Don’t_= allow filth of any kind to accumulate around the boiler - or boiler room. - - 4. =_Don’t_= leave your shovel or any other tool out of its appointed - place when not in use. - - 5. =_Don’t_= fail to keep all the bright work about the boiler neat - and “shiny.” - - 6. =_Don’t_= forget that negligence causes great loss and danger. - - 7. =_Don’t_= fail to be alert and ready-minded and ready-headed about - the boiler and furnace. - - 8. =_Don’t_= read newspapers when on duty. - - 9. =_Don’t_= fire up too quickly. - - 10. =_Don’t_= let any water or dampness come on the outside of your - boiler. - - 11. =_Don’t_= let any dampness get into the boiler and pipe coverings. - - 12. =_Don’t_= fail to see that you have plenty of water in the boiler - in the morning. - - 13. =_Don’t_= fail to keep the water at the same height in the boiler - all day. - - 14. =_Don’t_= let any one talk to you when firing. - - 15. =_Don’t_= allow water to remain on the floor about the boiler. - - 16. =_Don’t_= fail to blow off steam once or twice per day according - as the water is more or less pure. - - 17. =_Don’t_= fail to close the blow-off cock, when blowing off, when - the water in the boiler has sunk to one and a half inches. - - 18. =_Don’t fail_=, while cleaning the boiler, to examine and clean - all cocks, valves and pipes and look to all joints and packings. - - 19. =_Don’t_= commence cleaning the boiler until it has had time to - cool. - - 20. =_Don’t_= forget daily to see that the safety-valve moves freely - and is tight. - - 21. =_Don’t_= fail to clean the boiler inside frequently and - carefully. - - 22. =_Don’t_= fail to notice that the steam gauge is in order. - - 23. =_Don’t_= fail to keep an eye out for leaks and have them - repaired immediately, no matter how small. - - 24. =_Don’t_= fail to empty the boiler every week or two and re-fill - it with fresh water. - - 25. =_Don’t_= let any air into the furnace, except what goes through - the grate-bars, or the smoke burners, so called, by which the air is - highly heated. - - 26. =_Don’t_= increase the load on the safety-valve beyond the - pressure allowed by the inspector. - - 27. =_Don’t_= fail to open the doors of the furnace and start the - pump when the pressure is increased beyond the amount allowed, _but_ - - 28. =_Don’t_= fail to draw the fires _when there is danger_ from the - water having fallen too low. - - 29. =_Don’t_= fail to check the fire—if too hot to draw, do it with - fresh coal, damp ashes, clinkers or soil; _and_ - - 30. =_Don’t_= fail to open the doors of the furnace and close the - ash-pit doors at the time the fire is checked—_and_ - - 31. =_Don’t_= decrease the steam pressure by feeding in water or - suddenly blowing off steam, _and_ - - 32. =_Don’t_= touch the safety-valve, even if it be opened or closed, - _and_ - - 33. =_Don’t_= change the feed apparatus if it is working, or the - throttle-valve be open; let them both remain as they are for a short - time, _and_ - - 34. =_Don’t_= fail to change them very cautiously and slowly when you - close them, and - - 35. =_Don’t_= fail to be very cool and brave while resolute in - observing these last seven “Don’ts.” - - 36. =_Don’t_= fail to keep yourself neat and tidy. - - 37. =_Don’t_= fail to be polite as well as neat and brave. - - 38. =_Don’t_= fail to keep the tubes clear and free from soot and - ashes. - - 39. =_Don’t_= let too many ashes gather in the ash-pit. - - 40. =_Don’t_= disturb the fire when it is burning good nor stir it up - too often. - - 41. =_Don’t_= be afraid to get instruction from books and engineering - papers. - - 42. =_Don’t_= fail to make an honest self-examination as to points - upon which you may be ignorant, and really need to know in order to - properly attend to your duties. - - 43. =_Don’t_= allow too much smoke to issue from the top of the - chimney if the cause lies within your power to prevent it. - - 44. =_Don’t_= think that after working at firing and its kindred - duties for a year or two that _the whole subject_ of engineering has - been learned. - - 45. =_Don’t_= forget that one of the best helps in getting forward - is the possession of a vigorous and well-balanced mind and body—this - covers temperance and kindred virtues and a willingness to acquire - and impart knowledge. - - 46. =_Don’t_= forget to have your steam-gauge tested at least once in - three months. - - 47. =_Don’t_= use a wire or metallic rod as a handle to a swab in - cleaning the glass tube of a water-gauge for the glass may suddenly - fly to pieces when in use within a short time afterwards. - - 48. =_Don’t_= forget that steam pumps require as much attention as a - steam engine. - - 49. =_Don’t_= run a steam pump piston, unless in an emergency, at a - speed exceeding 80 to 100 feet per minute. - - 50. =_Don’t_= do anything without a good reason for it about the - engine or boiler, but when you are obliged to do anything, do it - thoroughly and as quickly as possible. - - 51. =_Don’t_= forget to sprinkle a thin layer of coal on the grates - before lighting the shavings and wood in the morning. This practice - preserves the grate bars. - - 52. =_Don’t_= take the cap off a bearing and remove the upper brass - simply to see if things are working well; if there is any trouble it - will soon give you notice, and, besides, you never can replace the - brass in exactly its former position, so that you may find that the - bearing will heat soon afterwards, owing to your own uncalled-for - interference. - - 53. =_Don’t_= put sulphur on a hot bearing, unless you intend to ruin - the brasses. - - 54. =_Don’t_= use washed waste that has a harsh feel, as the - chemicals used in cleansing it have not been thoroughly removed. - - 55. =_Don’t_=, in case of an extensive fire, involving the whole - business, rush off without drawing the fires, and raising and - _propping open_ the safety valve of the boiler. - - 56. =_Don’t_= fail to preserve your health, for “a sound mind in a - sound body” is beyond a money valuation. - - 57. =_Don’t_= fail to remember that engineers and firemen are in - control of the great underlying force of modern civilization; hence, - to do nothing to lower the dignity of the profession. - - 58. =_Don’t_= forget that in the care and management of - the steam boiler the first thing required is an unceasing - watchfulness—_watch-care_. - - 59. =_Don’t_= forget that an intemperate, reckless or indifferent man - has no business in the place of trust of a steam boiler attendant. - - 60. =_Don’t_= allow even a day to pass without adding one or more - facts to your knowledge of engineering in some of its branches. - - - - -STEAM GENERATORS. - - -In the examinations held by duly appointed officers to determine the -fitness of candidates for receiving an engineer’s license the principal -stress is laid upon the applicant’s knowledge of the parts and true -proportions of the various designs of steam boilers, and his experience -in managing them. - -In fact, if there were no boilers there would be no examinations, as -the laws are framed, certificates issued and steam boiler inspection -companies formed to assure the public safety in life, limb and -property, from the dangers arising from so-called mysterious boiler -explosions. - -Hence an almost undue proportion of engineers’ examinations are devoted -to the steam boiler, its management and construction. But the subject -is worthy of the best and most thoughtful attention. Every year adds to -the number of steam boilers in use. With the expanding area and growth -of population, the number of steam plants are multiplied and in turn -each new steam boiler demands a careful attendant. - -There is this difference between the boiler and the engine. When the -latter is delivered from the shop and set up, it does its work with an -almost unvarying uniformity, while the boiler is a constant care. It is -admitted that the engine has reached a much greater state of perfection -and does its duty with very much more reliability than the boiler. - -Even when vigilant precautions are observed, from the moment a steam -boiler is constructed until it is finally destroyed there are numerous -insidious agents perpetually at work which tend to weaken it. There is -nothing from which the iron can draw sustenance to replace its losses. -The atmosphere without and the air within the boiler, the water as -it enters through the feed-pipe and containing mineral and organic -substances, steam into which the water is converted, the sediment which -is precipitated by boiling the water, the fire and the sulphurous and -other acids of the fuel, are all natural enemies of the iron; they -sap its strength, not only while the boiler is at work and undergoing -constant strain, but in the morning before fire is started, and at -noon, night, Sundays, and other holidays it is preyed upon by these and -other corroding agents. - -These are the reasons which impress the true engineer with a constant -solicitude regarding the daily and even momentary action of the steam -generator. - - -DESCRIPTION. - -The Steam Boiler in its simplest form was simply a closed vessel partly -filled with water and which was heated by a fire box, but as steam -plants are divided into two principal parts, the engine and the boiler, -so the latter is divided again into the furnace and boiler, each of -which is essential to the other. The furnace contains the fuel to be -burnt, the boiler contains the water to be evaporated. - -There must be a steam space to hold the steam when generated; heating -surface to transmit the heat from the burning fuel to the water; a -chimney or other apparatus to cause a draught to the furnace and -to carry away the products of combustion; and various fittings for -supplying the boiler with water, for carrying away the steam when -formed to the engine in which it is used; for allowing steam to escape -into the open air when it forms faster than it can be used; for -ascertaining the quantity of water in the boiler, for ascertaining the -pressure of the steam, etc., all of which, together with the engine and -its appliances is called A STEAM PLANT. - -The forms in which steam generators are built are numerous, but may -be divided into three classes, viz: stationary, locomotive and marine -boilers, which terms designate the uses for which they are intended; -in this work we have to deal mainly with the first-named, although a -description with illustration is given of each type or form. - - -AN UPRIGHT STEAM BOILER. - -To illustrate the operations of a steam generator, we give the details -of an appliance, which may be compared to the letter A of the alphabet, -or the figure 1 of the numerals, so simple is it. - -Fig. 11, is an elevation of boiler, fig. 12 a vertical section through -its axis, and fig. 13 a horizontal section through the furnace bars. - -[Illustration: Fig. 11.] - -[Illustration: Fig. 12.] - -The type of steam generator here exhibited is what is known as a -vertical tubular boiler. The outside casing or shell is cylindrical -in shape, and is composed of iron or steel plates riveted together. -The top, which is likewise composed of the same plates is slightly -dome-shaped, except at the center, which is away in order to receive -the chimney _a_, which is round in shape and formed of thin wrought -iron plates. The interior is shown in vertical section in fig. 12. -It consists of a furnace chamber, _b_, which contains the fire. The -furnace is formed like the shell of the boiler of wrought iron or -steel plates by flanging and riveting. The bottom is occupied by the -grating, on which rests the incandescent fuel. The grating consists of -a number of cast-iron bars, _d_ (fig. 12), and shown in plan in fig. -13, placed so as to have interstices between them like the grate of an -ordinary fireplace. The bottom of the furnace is firmly secured to the -outside shell of the boiler in the manner shown in fig. 12. The top -covering plate _cc_, is perforated with a number of circular holes of -from one and a half to three inches diameter, according to the size of -the boiler. Into each of these holes is fixed a vertical tube made of -brass, wrought iron, or steel, shown at _fff_ (fig. 12). These tubes -pass through similar holes, at their top ends in the plate _g_, which -latter is firmly riveted to the outside shell of the boiler. The tubes -are also firmly attached to the two plates, _cc_, _g_. They serve to -convey the flame, smoke, and hot air from the fire to the smoke box, -_h_, and the chimney, _a_, and at the same time their sides provide -ample heating surface to allow the heat contained in the products of -combustion to escape into the water. The fresh fuel is thrown on the -grating when required through the fire door, A (fig. 11). The ashes, -cinders, etc., fall between the fire bars into the ash pit, B (fig. -12). The water is contained in the space between the shell of the -boiler, the furnace chamber, and the tubes. It is kept at or about the -level, _ww_ (fig. 12), the space above this part being reserved for -the steam as it rises. The heat, of course, escapes into the water, -through the sides and top plate of the furnace, and through the sides -of the tubes. The steam which, as it rises from the boiling water, -ascends into the space above _ww_, is thence led away by the steam -pipe to the engine. Unless consumed quickly enough by the engine, the -steam would accumulate too much within the boiler, and its pressure -would rise to a dangerous point. To provide against this contingency -the steam is enabled to escape when it rises above a certain pressure -through the safety-valve, which is shown in sketch on the top of the -boiler in fig. 11. The details of the construction of safety-valves -will be found fully described in another section of this work, which -is devoted exclusively to the consideration of boiler fittings. In the -same chapters will be found full descriptions of the various fittings -and accessories of boilers, such as the water and pressure gauges, -the apparatus for feeding the boiler with water, for producing the -requisite draught of air to maintain the combustion, and also the -particulars of the construction of the boilers themselves and their -furnaces. - -[Illustration: Fig. 13.] - - -THE GROWTH OF THE STEAM BOILER. - -After the first crude forms, such as that used in connection with the -Baranca and Newcomen engine, and numerous others, the steam boiler -which came into very general use was _the plain cylinder boiler_. An -illustration is given of this in figures 14 and 15. - -It consists of a cylinder A, formed of iron plate with hemispherical -ends B. B. set horizontally in brick work C. The lower part of this -cylinder contains the water, the upper part the steam. The furnace D -is outside the cylinder, being beneath one end; it consists simply of -grate bars _e e_ set in the brick work at a convenient distance below -the bottom of the boiler. - -[Illustration: Fig. 14.] - -[Illustration: Fig. 15.] - -The sides and front of the furnace are walls of brick work, which, -being continued upwards support the end of the cylinder. The fuel is -thrown on the bars through the door which is set in the front brick -work. The air enters between the grate bars from below. The portion -below the bars is called the ash pit. The flame and hot gases, when -formed, first strike on the bottom of the boiler, and are then carried -forward by the draft, to the so-called bridge wall _o_, which is a -projecting piece of brick work which contracts the area of the flue _n_ -and forces all the products of combustion to keep close to the bottom -of the boiler. - -Thence the gases pass along the flue _n_, and return part one side -of the cylinder in the flue _m_ (fig. 15) and back again by the other -side flue _m_ to the far end of the boiler, whence they escape up the -chimney. This latter is provided with a door or damper _p_, which can -be closed or opened at will, so as to regulate the draught. - -This boiler has been in use for nearly one hundred years, but has two -great defects. The first is that the area of heating surface, that is -the parts of the boiler in contact with the flames, is too small in -proportion to the bulk of the boiler; the second is, that if the water -contains solid matter in solution, as nearly all the water does to a -greater or less extent, this matter becomes deposited on the bottom -of the boiler just where the greatest evaporation takes place. The -deposit, being a non-conductor, prevents the heat of the fuel from -reaching the water in sufficient quantities, thus rendering the heating -surface inefficient; and further, by preventing the heat from escaping -to the water, it causes the plates to become unduly heated, and quickly -burnt out. - -There is another defect belonging to this system of boiler to which -many engineers attach great importance, viz.: that the temperature -in each of the three flues _n_, _m_, _m´_ is very different, and -consequently that the metal of which the shell of the boiler is -composed expands very unequally in each of the flues, and cracks -are very likely to take place when the effects of the changes of -temperature are most felt. It will be noted that the flames and gases -in this earliest type of steam boiler make three turns before reaching -the chimney, and as these boilers were made frequently as much as 40 -feet long it gave the extreme length of 120 feet to the heat products. - -THE CORNISH BOILER is the next form in time and excellence. This is -illustrated in figures 16 and 17. - -It consists also of a cylindrical shell _A_, with flat ends as -exhibited in cuts. The furnace, however, instead of being situated -underneath the front end of the shell, is enclosed in it in a second -cylinder _B_, having usually a diameter a little greater than half that -of the boiler shell. The arrangement of the grate and bridge is evident -from the diagram. After passing the bridge wall the heat products -travel along through the internal cylinder _B_, till they reach the -back end of the boiler; then return to the front again, by the two side -flues _m_, _m_´, and thence back again to the chimney by the bottom of -flue _n_. - -In this form of boiler the heating surface exceeds that of the last -described by an amount equal to the area of the internal flues, while -the internal capacity is diminished by its cubic contents; hence for -boilers of equal external dimensions, the ratio of heating surface -to mass of water to be heated, is greatly increased. Boilers of this -sort can, however, never be made of as small diameters as the plain -cylindrical sort, on account of the necessity of finding room inside, -below the water level, for the furnace and flue. - -[Illustration: Fig. 16.] - -[Illustration: Fig. 17.] - -The disadvantage, too, of the deposits mentioned in the plain cylinder -is, to a great extent got over in the Cornish boiler, for the bottom, -where the deposit chiefly takes place, is the coolest instead of being -the hottest part of the heating surface. - -But the disadvantage of unequal expansion also exists in this type -of boiler, as the internal flue in the Cornish system is the hottest -portion of the boiler, and consequently undergoes a greater lengthways -expansion than the flues. The result is to bulge out the ends, and when -the boiler is out of use, the flue returns to its regular size, and -thus has a tendency to work loose from the ends to which it is riveted -and if the ends are too rigid to move, a very serious strain comes on -the points of the flue. - -Even while in use the flue of a Cornish boiler is liable to undergo -great changes in temperature, according to the state of the fire; -when this latter is very low, or when fresh fuel has been thrown on, -the temperature is a minimum and reaches a maximum again when the -fresh fuel commences to burn fiercely. This constant expansion and -contraction is found in practice to also so weaken the tube that -it frequently collapses or is pressed together, resulting in great -disaster. - -This led to the production and adoption of the— - -LANCASHIRE BOILER, contrived to remedy this inconvenience and also to -attain a more perfect combustion, the arrangement of the furnaces of -which is shown in fig. 19 and fig. 20. - -It will be observed that there are two internal furnaces instead -of one, as in the Cornish type. These furnaces are sometimes each -continued as a separate flue to the other end of the boiler as shown -in the cuts; but as a rule they emerge into one internal flue. They -are supposed to be fired alternately, and the smoke and unburned gases -issuing from the fresh fuel are ignited in the flue by the hot air -proceeding from the other furnace, the fuel in which is in a state of -incandescence. Thus all violent changes in the temperature are avoided, -and the waste of fuel due to unburned gases is avoided, if the firing -is properly conducted. - -[Illustration: LANCASHIRE BOILER—Fig. 18.] - -The disadvantage of the Lancashire boiler is the difficulty of finding -adequate room for the two furnaces without unduly increasing the -diameter of the shell. Low furnaces are extremely unfavorable to -complete combustion, the comparatively cold crown plates, when they are -in contact with the water of the boiler, extinguishing the flames from -the fuel, when they are just formed, while the narrow space between -the fuel and the crown does not admit the proper quantity of air being -supplied above the fuel to complete the combustion of the gases, as -they arise. - -On the other hand, though this boiler favors the formation of the -smoke, it supplies the means of completing the combustion afterwards, -as before explained, by means of the hot air from the second furnace. - -[Illustration: Fig. 18 (_a_)] - -Another disadvantage is the danger of collapsing the internal flue -already spoken of; this is remedied by the introduction of what are -called the galloway tubes, illustrated in the cut shown on this page, -which is a cross section of the water tubes shown in Figs. 18 and 20. - -These tubes not only contribute to strengthen the flues but they add to -the heating surface and greatly promote the circulation so important in -the water space. - -NOTE. - -These descriptions and illustrations of the Lancashire boiler are of -general value, owing to the fact that very many exhaustive tests and -experiments upon steam economy have been made and permanently recorded -in connection with this form of steam generator. - -In the GALLOWAY form of boiler the flue is sustained and stiffened by -the introduction of numerous conical tubes, flanged at the two ends and -riveted across the flue. These tubes, a sketch of which are given in -fig. 18 (_a_), are in free communication with the water of the boiler, -and besides acting as stiffeners, they also serve to increase the -heating surface and to promote circulation. - -[Illustration: Figs. 19, 20.] - -The illustration (figs. 18, 19 and 20) give all the principal details -of a Lancashire boiler fitted with Galloway tubes. Fig. 18 represents a -longitudinal section and figs. 19 and 20 shows on a large scale an end -view of the front of the boiler with its fittings and also a transverse -section. The arrangement of the furnaces, flues, and the Galloway tubes -is sufficiently obvious from the drawings. The usual length of these -boilers is 27 feet, though they are occasionally made as short as 21 -feet. - -The minimum diameter of the furnaces is 33 inches, and in order to -contain these comfortably the diameter of the boiler should not be -less than 7 feet. The ends of the boiler are flat, and are prevented -from bulging outwards by being held in place by the furnaces and flues -which stay the two ends together and also by the so-called gusset stays -_e_, _e_. In addition to the latter the flat ends of the boiler have -longitudinal rods to tie them together; one of these is shown at _A_, -_A_, fig. 18. - -The steam is collected in the pipe _S_, which is perforated all along -the top so as to admit the steam and exclude the water spray which may -rise to the surface during ebullition. The steam thence passes to the -stop valve _T_ outside the boiler and thence to the steam pipes to the -engines. - -There are two safety valves on top of the boiler on _B_ (fig. 18), -being of the dead weight type described hereafter, and the other, _C_, -being a so-called low water safety valve. It is attached by means of a -lever and rod to the float _F_, which ordinarily rests on the surface -of the water. When through any neglect, the water sinks below its -proper level the float sinks also, causing the valve to open, thus -allowing steam to escape and giving an alarm. _M_ is the manhole with -its covering plate, which admits of access to the interior of the -boiler and _H_ is the mud hole by which the sediment which accumulates -all along the bottom is raked out. Below the front end and underneath, -the pipe and stay valve are shown, by which the boiler can be emptied -or blown off. - -On the front of the boiler (fig. 19) are shown, the pressure gauges, -the water gauges and the furnace door; _K_ is the feed pipe; _R_, _R_, -a pipe and cock for blowing off steam. In the front of the setting are -shown two iron doors by which access may be gained to the two lower -external flues for cleaning purposes. - -In the Lancashire boiler it is considered advisable to take the -products of combustion, after they leave the internal flues, along the -bottom of the boiler, and then back to the chimney by the side. When -this plan is adopted the bottom is kept hotter than would otherwise be -the case, and circulation is promoted, which prevents the coldest water -from accumulating at the bottom. - -The Galloway (or Lancashire) boiler is considered the most economical -boiler used in England, and is being introduced into the United States -with success. The long traverse of heat provided (three turns of about -27 feet each) contributes greatly to its efficiency. - -It may be useful to add the following data relating to this approved -steam generator, being the principal dimensions and other data of the -boiler shown in fig. 18: - - Steam pressure, 75 lbs. per sq. inch. - Length, 27 feet. - Diameter, 7 feet. - Weight, total, 15-1/2 tons. - Shell plates, 7/16 inch. - Furnace diameter, 33 inches. - Furnace Plates, 3/8 inch. - End plates, 1/2 inch. - Grate area, 33 sq. feet. - Heating surface: - In furnace and flues 450 sq. feet. - In Galloway pipes, 30 „ - In external flues, 370 „ - ---- - 850 sq. feet. - -We have thus detailed step by step the improvement of the steam boiler -to a point where it is necessary to describe at length the locomotive, -the marine, the horizontal tubular and the water tube boilers, which -four forms comprehend ninety-nine out of one hundred steam generators -in use in the civilized world at the present time. - - -MARINE BOILERS. - -The boilers used on board steamships are of two principal types. The -older sort used for steam of comparatively low temperature, viz.: up -to 35 lbs. per square inch, is usually made of flat plates stayed -together, after the manner of the exterior and interior fire boxes of a -locomotive boiler. - -Medium high pressure marine boilers, constructed for steam of 60 to -150 lbs. per square inch, are circular or oval in cross section, and -are fitted with round interior furnaces and flues like land boilers. -There are many variations of marine boilers, adapted to suit special -circumstances. Fig. 22 shows a front elevation and partial sections of -a pair of such boilers and Fig. 23 shows one of them in longitudinal -vertical section. - -THE MARINE STEAM BOILER - -[Illustration: Fig. 22.] - -[Illustration: Fig. 23.] - -It will be seen from these drawings that there are three internal -cylindrical furnaces at each end of these boilers, making in all six -furnaces per boiler. The firing takes place at both ends. The flame and -hot gases from each furnace, after passing over the bridge wall enter a -flat-sided rectangular combustion chamber and then travel through tubes -to the front uptake (_i.e._ the smoke bonnet or breaching), and so on -to the chimney. - -The sides of the combustion chambers are stayed to each other and to -the shell plate of the boiler; the tops are strengthened in the same -manner as the crowns of locomotive boilers, and the flat plates of the -boiler shell are stayed together by means of long bolts, which can be -lengthened up by means of nuts at their ends. Access is gained to the -uptakes for purposes of cleaning, repairs of tubes, etc., by means of -their doors on their fronts just above the furnace doors. The steam is -collected in the large cylindrical receivers shown above each boiler. -The material of construction is mild steel. - -The following are the principal dimensions and other particulars of one -of these boilers: - - Length from front to back, 20 feet. - Diameter of shell, 15 feet 6 inches. - Length of furnace, 6 feet 10 inches. - Diameter of furnace, 3 feet 10 inches. - Length of tubes, 6 feet 9 inches. - Diameter of tubes, 3-1/2 inches. - No. of tubes, 516. - Thickness of shell plates, 15/16. - Thickness of tube plates, 3/4. - Grate area, 126-1/2 square feet. - Heating surface, 4015 square feet. - Steam pressure, 80 lbs. per sq. inch. - -Fig. 24 is a sketch of a modern marine boiler, which is only fired -from one end, and is in consequence much shorter in proportion to its -diameter than the type illustrated in figs. 22 and 23. - -Marine boilers over nine feet in diameter have generally two furnaces, -those over 13 to 14 feet, three, while the very largest boilers used -on first-class mail steamers, and which often exceed fifteen feet in -diameter, have four furnaces. - -In the marine boiler the course taken by the products of combustion -is as follows; the coal enters through the furnace doors on to the -fire-bars, the heat and flames pass over the fire bridge into the flame -or combustion chamber, thence through the tubes into the smoke-box, up -the up-take and funnel into the air. - -[Illustration: Fig. 24.] - -The fittings to a marine boiler are—funnel and air casings, up-takes -and air casings, smoke boxes and doors, fire doors, bars, bridges, -and bearers, main steam stop valve, donkey valve, safety valves and -drain pipes, main and donkey feed check valves, blow-off and scum -cocks, water gauge glasses on front and back of boiler, test water cock -for trying density of water, steam cock for whistle, and another for -winches on deck. - -A fitting, called a blast pipe, is sometimes placed in the throat of -the funnel. It consists of a wrought iron pipe, having a conical nozzle -within the funnel pointing upwards, the other end being connected to -a cock, which latter is bolted on to the steam space or dome of the -boiler. It is used for increasing the intensity of the draft, the -upward current of steam forcing the air out of the funnel at a great -velocity; and the air having to be replaced by a fresh supply through -the ash-pits and bars of the furnaces, a greater speed of combustion is -obtained than would otherwise be due to simple draft alone. - -Boilers are fitted with dry and wet uptakes, which differ from each -other as follows:—The dry uptake is wholly outside the boiler, and -consists of an external casing bolted on to the firing end of the -boiler, covering the tubes and forming the smoke-box, and is fitted -with suitable tube doors. A wet uptake is carried back from the firing -ends of the boiler into its steam space, and is wholly surrounded -by water and steam. The dry uptake seldom requires serious repair; -but the wet uptake, owing to its exposure to pressure, steam, and -water, requires constant attention and repair, and is very liable to -corrosion, being constantly wetted and dried in the neighborhood of the -water-line. The narrow water space between both front uptakes is also -very liable to become burnt, owing to accumulation of salt. The flue -boilers of many tugs and ferry boats are fitted with wet uptakes. - -A superheater is a vessel usually placed in the uptake, or at the base -of the funnel of a marine boiler, and so arranged that the waste heat -from the furnaces shall pass around and through it prior to escaping up -the chimney. It is used for drying or heating the steam from the main -boiler before it enters the steam pipes to the engine. The simplest -form of superheater consists of a wrought iron drum filled with tubes. -The heat or flame passes through the tubes and around the shell of -the drum, the steam being inside the drum. Superheaters are usually -fitted with a stop valve in connection with the boiler, by means of -which it can be shut off; and also one to the steam pipe of the engine; -arrangements are also usually made for mixing the steam or working -independently of the superheater. - -A safety-valve is also fitted and a gauge glass; the latter is to show -whether the superheater is clear of water, as priming will sometimes -fill it up. - -The special fittings of the marine boiler will be more particularly -described hereafter as well as the stays, riveting, strength, etc., -etc. - -The use of the surface condenser in connection with the marine boiler -was an immense step toward increasing its efficiency. In 1840 the -average pressure used in marine boilers was only 7 or 8 lbs. to the -square inch, the steam being made with the two-flue pattern of boiler, -sea water being used for feed; as the steam pressure increased as now -to 150 to 200 lbs. to the square inch, greater and greater difficulty -was experienced from salt incrustation—in many cases the tubes did not -last long and frequently gave much trouble, until the introduction of -the surface condenser, which supplied fresh water to the boilers. - -[Illustration: Fig. 25] - - -THE SURFACE CONDENSER. - -The condenser is an oblong or circular box of cast iron fitted in one -of two ways, either with the tubes horizontal or vertical; at each end -are fixed the tube plates, generally made of brass, and the tubes pass -through the plates as well as through a supporting plate in the middle -of the condenser. Each end of the condenser is fitted with doors for -the purpose of enabling the tube ends to be examined, drawn, or packed, -as may be necessary. The tube ends are packed in various ways, and the -tubes are made of brass, so as to resist the action of the water. The -water is generally sucked through the tubes by the circulating pump, -and the steam is condensed by coming in contact with the external -surface of the tubes. In some cases the water is applied to the -external surface, and the steam exhausted through the tubes; but this -practice is now generally given up in modern surface condensers. The -packing round the tube ends keeps them quite tight, and in the event -of a split tube, a wooden plug is put in each end until an opportunity -offers for drawing it and replacing with a new one. - -The condenser may be made of any convenient shape. It sometimes forms -part of the casting supporting the cylinders of vertical engines; it -is also frequently made cylindrical with flat ends, as in fig. 25. The -ends form the tube plates to which the tubes are secured. The tubes -are, of course, open at the ends, and a space is left between the tube -plate and the outer covers, shown at each end of the condenser, to -allow of the circulation of water as shown by the arrows. - - -OPERATION OF THE CONDENSER. - -The cold water, which is forced through by a circulating pump, enters -at the bottom, and is compelled to pass forward through the lower set -of tubes by a horizontal dividing plate; it then returns through the -upper rows of tubes and passes out at the overflow; the tubes are thus -maintained at a low temperature. - -The tubes are made to pass right through the condensing chamber, and so -as to have no connection with its internal space. The steam is passed -into the condenser and there comes in contact with the cold external -surface of the tube, and is condensed, and removed as before, by the -air pump, as may be readily seen in the illustration (p. 65.) - -The advantages gained by the use of the surface condenser are: 1. The -feed water is hotter and fresh; being hotter, it saves the fuel that -would be used to bring it up to this heat; and being fresh it boils at -a lower temperature. 2. Not forming so much scale inside the boiler, -the heat passes through to the water more readily; and as the scum cock -is not used so freely, all the heat that would have been blown off is -saved. Its disadvantages are that being fresh water and forming no -scale on the boiler, it causes the boiler to rust. - -It is often said that one engineer will get more out of a ship than -another. In general it will be found that the most successful engineer -is the man who manages his stokers best. It is very difficult on -paper to define what is meant. It is a thing to be felt or seen, not -described. * * * * The engineer who really knows his business will give -his fires a fair chance to get away. He will work his engines up by -degrees and run a little slowly for the first few moments. - - -WATER TUBE STEAM BOILERS. - -[Illustration: WATER TUBE BOILER.—Fig. 26.] - -A popular form of steam boiler in use in the United States and Europe -is what is called the water tube boiler. This term is applied to a -class of boiler in which the water is contained in a series of tubes, -of comparatively small diameter, which communicate with each other and -with a common steam-chamber. The flames and hot gases circulate between -the tubes and are usually guided by partitions so as to act equally on -all portions of the tubes. There are many varieties of this type of -boiler of which the cut illustrates one: in this each tube is secured -at either end into a square cast-iron head, and each of these heads -has two openings, one communicating with the tube below and the other -with the tube above; the communication is effected by means of hollow -cast-iron caps shown at the end of the tubes; the caps have openings in -them corresponding with the openings in the tube heads to which they -are bolted. - -In the best forms of the water tube boilers, it is suspended entirely -independent of the brick work from wrought iron girders resting on iron -columns. This avoids any straining of the boiler from unequal expansion -between it and its enclosing walls and permits the brick work to be -repaired or removed, if necessary, without in any way disturbing the -boiler. This design is shown in Fig. 26. - -The distinguishing difference, which marks the water tube boiler -from others, consists in the fact that in the former the small tubes -are filled with water instead of the products of combustions; hence -the comparison, frequently made, between water-tube and _fire tube_ -boilers—the difference has been expressed in another way, “Water-tube -vs. shell boilers,” but the principle of steam production in both -systems remains the same; the heat from the combustible is transferred -to the water through the medium of iron plates and in both, the -furnaces, steam appliances, application of the draught, etc., is -substantially the same. In another important point do the systems -agree, _i.e._, in the average number of pounds of water evaporated -per lb. of combustible; it is in the thoroughness of construction -and skillfulness of adaptation to surroundings that produce the best -results. Water tube or sectional boilers, have been made since the -days of James Watt, in 1766, in many different forms and under various -names. Owing, however, to the imperfection of manufacture the system, -as compared to shell boilers, has been a failure until very recently; -various patterns of water-tube boilers are now in most favorable -and satisfactory use. The advantages claimed for this form of steam -generator are as follows: - -1. Safety from disastrous explosions, arising from the division of -the contents into small portions, and especially from details of -construction which make it tolerably certain that the rupture will be -local instead of a general violent explosion which liberates at once -large masses of steam and water. - -2. The small diameter of the tubes of which they are composed render -them much stronger than ordinary boilers. - -3. They can be cheaply built and easily repaired, as duplicate pieces -can be kept on hand. The various parts of a boiler can be transported -without great expense, trouble or delay; the form and proportions of a -boiler can be suited to any available space; and, again, the power can -be increased by simply adding more rows of tubes and increasing the -grate area. - -4. Their evaporative efficiency can be made equal to that of other -boilers, and, in fact, for equal proportions of heating and grate -surfaces, it is often a trifle higher. - -5. Thin heating surface in the furnace, avoiding the thick plates -necessarily used in ordinary boilers which not only hinder the -transmission of heat to the water, but admit of overheating. - -6. Joints removed from the fire. The use of lap welded water tubes with -their joints removed from the fire also avoid the unequal expansion of -riveted joints consequent upon their double thickness. - -7. Quick steaming. - -8. Accessibility for cleaning. - -9. Ease of handling and erecting. - -10. Economy and speediness of repairs. - -The known disadvantages of these boilers are - -1. They generally occupy more space and require more masonry than -ordinary boilers. - -2. On account of the small quantity of water which they contain, sudden -fluctuations of pressure are caused by any irregularities in supplying -the feed-water or in handling the fires, and the rapid and at times -violent generation of steam causes it to accumulate in the contracted -water-chambers, and leads to priming, with a consequent loss of water, -and to overheated tubes. - -3. The horizontal or inclined water tubes which mainly compose these -boilers, do not afford a ready outlet for the steam generated in -them. The steam bubbles cannot follow their natural tendency and rise -directly, but are generally obliged by friction to traverse the tube -slowly, and at times the accumulation of steam at the heated surfaces -causes the tubes to be split or burned. - -4. The use of water which forms deposits of solid matter still further -increases the liability to overheating of the tubes. It has been -claimed by some inventors that the rapid circulation of the water -through the tubes would prevent any deposit of scale or sediment in -them, but experience has proved this to be a grave error. Others have -said that the expansion of the tube would detach the scale as fast -as it was deposited and prevent any dangerous accumulation, but this -also has been proved an error. Again, the use of cast iron about these -boilers has frequently been a constant source of trouble from cracks, -etc. - - -CARE OF WATER TUBE BOILERS. - -The soot and ashes collect on _the exterior_ of the tubes in this form -of boilers, instead of inside the tubes, as in the tubular, and they -must be as carefully removed in one case as in the other; this can be -done by the use of blowing pipe and hose through openings left in the -brick work; in using bituminous coal the soot should be brushed off -when steam is down. - -All the inside and outside surfaces should be kept clean to avoid waste -of fuel; to aid in this service the best forms are provided with extra -facilities for cleaning. For inspection, remove the hand holes at both -ends of the tubes, and by holding a lamp at one end and looking in at -the other the condition of the surface can be freely seen. Push the -scraper through the tube to remove sediment, or if the scale is hard, -use the chipping scraper made for that purpose. - -Hand holes should be frequently removed and surfaces examined, -particularly in case of a new boiler. In replacing hand hole caps, -clean the surfaces without scratching or bruising, smear with oil and -screw up tight. - -The mud drum should be periodically examined and the sediment removed; -blow-off cocks and check valves should be examined each time the boiler -is cleaned; when surface blow-cocks are used they should be often -opened for a few minutes at a time; be sure that all openings for air -to boiler or flues _except through the fire_, are carefully stopped. - -If a boiler is not required for some time, empty and dry it thoroughly. -If this is impracticable, fill it quite full of water and put in a -quantity of washing soda; and external parts exposed to dampness should -receive a coating of linseed oil. Avoid all dampness in seatings or -coverings and see that no water comes in contact with the boiler from -any cause. - -Although this form of boiler is not liable to destructive explosion, -the same care should be exercised to avoid possible damage to boilers -and expensive delays. - - -SECTIONAL BOILERS. - -Probably one of the first sectional boilers brought into practical use -is one made of hollow cast iron spheres, each 8 inches in diameter, -externally, and 3/8 of an inch thick, connected by curved necks 3-1/2 -inches in diameter. These spheres are held together by wrought iron -bolts and caps, and in one direction are cast in sets of 2 or 4, which -are afterwards drawn together so as to give more or less heating -surface to the boiler according to the number used. - -NOTE. - -Owing to their multiplication of parts all sectional, including water -tube boilers, should be made with unusual care in their details of -construction, setting, fittings and proportions. It is to the attention -paid to these “points” that the sectional boilers are now coming into -more general favor. - - -LOCOMOTIVE BOILERS. - -The essential features of locomotive boilers are dictated by the duties -which they have to perform under peculiar conditions. The size and the -weight are limited by the fact that the boiler has to be transported -rapidly from place to place, and also that it has to fit in between -the frames of the locomotive; while at the same time, the pressure of -the steam has to be very great in order that with comparatively small -cylinder the engine may develop great power; moreover, the quantity of -water which has to be evaporated in a given time is very considerable. -To fulfil these latter conditions a large quantity of coal must be -burned on a fire grate of limited area; hence intense combustion is -necessary under a forced blast. To utilize advantageously the heat -thus generated, a large heating surface must be provided and this can -only be obtained by passing the products of combustion through a great -number of tubes of small diameter. - -The forced draught in a locomotive boiler is obtained by causing the -steam from the cylinders, after it has done its work, to be discharged -into the chimney by means of a pipe called the blast pipe; the lower -portion of this consists of two branches, one in communication with the -exhaust port of each cylinder. As each puff of steam from the blast -pipe escapes up the chimney it forces the air out in front of it, -causing a partial vacuum, which can only be supplied by the air rushing -through the furnace and tubes. - -The greater the body of steam escaping at each puff, and the more -rapid the succession of puffs, the more violent is the action of the -blast pipe in producing a draught, and consequently this contrivance -regulates the consumption of fuel and the evaporation of water to a -certain extent automatically, because when the engine is working its -hardest and using the most steam, the blast is at the same time most -efficacious. - -[Illustration: LOCOMOTIVE BOILER.—Fig. 27.] - -The blast pipe is perhaps, the most distinctive feature of the -locomotive boiler, and the one which has alone rendered it possible to -obtain large quantities of steam from so small a generator. The steam -blast of a locomotive has been compared to the breathing apparatus of a -man, and has rendered the mechanism described nearer a live thing than -any other device man has ever produced. - -On account of the oscillations, or violent motions to which the boiler -of locomotive engines are subject, weighted safety-valves are not -possible to be used and springs are used instead to hold the valves in -place. - -The locomotive form of steam boiler is sometimes used for stationary -engines, but owing to extra cost and increased liability to corrode in -the smaller passage they are not favorites. - -DESCRIPTION OF PAGE ILLUSTRATION. - -In fig. 27, F B represents the fire box or furnace; F D, fire door; -D P, deflector plate; F T P, fire box tube plate; F B R S, fire box -roof stays; S T P, smoke box tube plate; S B, smoke box; S B D, -smoke box door; S D, steam dome; O S, outer shell; R S V, Ramsbottom -safety-valve; F, funnel or chimney. - -[Illustration: Fig. 28.] - -The crown plate of the fire-box being flat requires to be efficiently -stayed, and for this purpose girder stays called fox roof stays are -mostly used, as shown in the figure. The stays are now made of cast -steel for locomotives. They rest at the two ends on the vertical plates -of the fire-box, and sustain the pressure on the fire-box crown by a -series of bolts passing through the plate and girder stay, secured by -nuts and washers. Fig. 28 is a plan and elevation of a wrought-iron -roof stay. - -Another method adopted in locomotive types of marine boilers for -staying the flat crown of the fire-box to the circular upper plate is -shown in fig. 29—namely, by wrought-iron vertical bar stays secured by -nuts and washers to the fire-box with a fork end and pin to angle-iron -pieces riveted to the boiler shell. - -[Illustration: Fig. 29.] - -The letters in this figure refer to the same parts of the boiler as do -those in fig. 27, _i.e._, F B to the fire-box, etc., etc. - -It was formerly the custom to make the tubes much longer than shown -in the fig., with the object of gaining heating surface; but modern -experience has shown that the last three or four feet next the smoke -box were of little or no use, because, by the time the products of -combustion reached this part of the heating surface, their temperature -was so reduced that but little additional heat could be abstracted from -them. The tubes, in addition to acting as flues and heating surface, -fulfil also the function of stays to the flat end of the barrel of the -boiler, and the portion of the fire box opposite to it. - -In addition to the staying power derived from the tubes, the smoke box, -tube plate and the front shell plate are stayed together by several -long rods. - -[Illustration: THE HORIZONTAL TUBULAR BOILER.—Fig. 30.] - -STANDARD HORIZONTAL TUBULAR STEAM BOILER. - -TABLE OF SIZES, PROPORTIONS, ETC.: - - ========+========+=======+=======+======+========+=========+========+======= - Diameter| Length |Gauge | Gauge |Number|Diameter| Length |Square |Nominal - of | of | of | of | of | of | of |feet of | Horse - Shell. | Shell. |Shell. | Heads.|Tubes.| Tubes. | Tubes. |Heating | Power. - | | | | | | |Surface.| - --------+--------+-------+-------+------+--------+---------+--------+------- - 72 in.|19ft.4in|3/8 in.| 1/2in.| 80 |4 in.|18ft.0in.| 1,500 | 100 - 72 „ |18 „ 4 „|3/8 „ | 1/2 „ | 86 |3-1/2 „ |17 „ 0 „ | 1,500 | 100 - 72 „ |17 „ 4 „|3/8 „ | 1/2 „ | 108 |3 „ |16 „ 0 „ | 1,500 | 100 - --------+--------+-------+-------+------+--------+---------+--------+------- - 66 „ |18 „ 4 „|3/8 „ | 1/2 „ | 74 |3-1/2 „ |17 „ 0 „ | 1,350 | 90 - 66 „ |17 „ 4 „|3/8 „ | 1/2 „ | 92 |3 „ |16 „ 0 „ | 1,350 | 90 - --------+--------+-------+-------+------+--------+---------+--------+------- - 60 „ |18 „ 3 „|3/8 „ | 1/2 „ | 78 |3 „ |17 „ 0 „ | 1,200 | 80 - 60 „ |17 „ 3 „|3/8 „ | 1/2 „ | 76 |3 „ |16 „ 0 „ | 1,125 | 75 - 60 „ |16 „ 3 „|3/8 „ | 1/2 „ | 77 |3 „ |15 „ 0 „ | 1,050 | 70 - 60 „ |16 „ 3 „|3/8 „ | 1/2 „ | 70 |3 „ |15 „ 0 „ | 975 | 65 - 60 „ |16 „ 3 „|3/8 „ | 1/2 „ | 64 |3 „ |15 „ 0 „ | 900 | 60 - --------+--------+-------+-------+------+--------+---------+--------+------- - 54 „ |17 „ 3 „|5/16 „ |7/16 „ | 60 |3 „ |16 „ 0 „ | 900 | 50 - 54 „ |17 „ 3 „|5/16 „ |7/16 „ | 56 |3 „ |16 „ 0 „ | 825 | 55 - 54 „ |16 „ 3 „|5/16 „ |7/16 „ | 52 |3 „ |15 „ 0 „ | 750 | 50 - 54 „ |16 „ 3 „|5/16 „ |7/16 „ | 46 |3 „ |15 „ 0 „ | 675 | 45 - 54 „ |16 „ 3 „|5/16 „ |7/16 „ | 40 |3 „ |15 „ 0 „ | 600 | 40 - --------+--------+-------+-------+------+--------+---------+--------+------- - 48 „ |17 „ 2 „|5/16 „ |7/16 „ | 50 |3 „ |16 „ 0 „ | 750 | 50 - 48 „ |16 „ 2 „|5/16 „ |7/16 „ | 48 |3 „ |15 „ 0 „ | 675 | 45 - 48 „ |16 „ 2 „|5/16 „ |7/16 „ | 42 |3 „ |15 „ 0 „ | 600 | 40 - --------+--------+-------+-------+------+--------+---------+--------+------- - 42 „ |16 „ 2 „|1/4 „ | 3/8 „ | 36 |3 „ |15 „ 0 „ | 525 | 85 - 42 „ |15 „ 2 „|1/4 „ | 3/8 „ | 32 |3 „ |14 „ 0 „ | 450 | 30 - 42 „ |14 „ 2 „|1/4 „ | 3/8 „ | 28 |3 „ |13 „ 0 „ | 375 | 25 - --------+--------+-------+-------+------+--------+---------+--------+------- - 36 „ |14 „ 2 „|1/4 „ | 3/8 „ | 36 |2-1/2 „ |13 „ 0 „ | 375 | 25 - 36 „ |14 „ 2 „|1/4 „ | 3/8 „ | 28 |2-1/2 „ |13 „ 0 „ | 300 | 20 - 36 „ |13 „ 2 „|1/4 „ | 3/8 „ | 20 |2-1/2 „ |12 „ 0 „ | 225 | 15 - 36 „ |12 „ 2 „|1/4 „ | 3/8 „ | 14 |2-1/2 „ |11 „ 0 „ | 150 | 10 - ========+========+=======+=======+======+========+=========+========+======= - -NOTE. - -In estimating the horse power by means of the above table, 15 square -feet has been allowed for each horse power, and the number of feet in -each boiler is given _in round numbers_. This table is one used in -every-day practice by boiler makers. - -THE FLUE BOILER. - -[Illustration: THE TWO FLUE BOILER.—Fig. 31.] - -[Illustration: THE SIX INCH FLUE BOILER.—Fig. 32.] - - -THE HORIZONTAL TUBULAR STEAM BOILER. - -The great majority of stationary boilers are cylindrical or round -shaped, because— - -1. The cylindrical form is the strongest. - -2. It is the cheapest. - -3. It permits the use of thinner metal. - -4. It is the safest. - -5. It is inspected without difficulty. - -6. It is most symmetrical. - -7. It is manufactured easier. - -8. It resists internal strain better. - -9. It resists external strain also. - -10. It can be stayed or strengthened better. - -11. It encloses the greatest volume with least material. - -12. It is the result of many years’ experience in boiler practice. - -13. It is the form adopted or preferred by all experienced engineers. - -It follows, too, that _the horizontal tubular boiler_, substantially -as shown in fig. 30, is the standard steam boiler; engineers and steam -power owners cling with great tenacity to this approved form, which is -an outgrowth of one hundred years’ experience in steam production. - -In the plain horizontal tubular boiler shown in cuts, the shell is -filled with as many small tubes varying from two inches to four inches -in diameter as is consistent with the circulation and steam space. In -firing this type of boiler the combustion first takes place under the -shell, and the products, such as heat, flame, and gas, pass through -the small tubes to the chimney, although in the triple draught pattern -of the tubular boiler, the heat products pass, as will hereafter be -explained, a second time through the boiler tubes, making three turns -before the final loss of the extra heat takes place. - -The illustrations on pages 78 and 80 exhibit the gradual advances to -the horizontal tubular by the two-flued boiler (fig. 31) of the six -flues (fig. 32) and of the locomotive Portable Boiler (fig. 33). The -vertical or upright tubular boiler is but another modification of the -horizontal tubular. - -[Illustration: THE LOCOMOTIVE PORTABLE BOILER.—Fig. 33.] - -In parts of the vertical boiler there is very little circulation and -the corrosion on the inner side is such as to wear the boiler rapidly. -In the ash pit, ashes and any dampness that may be about the place also -causes rapid corrosion. The upper part of the tubes and tube sheet are -frequently injured; for instance, if the tubes pass all the way through -to the upper tube sheet, providing there is no cone top, when the fire -is first made under the boiler, combustion at times does not take place -until the gases pass nearly through the tubes. The water usually being -carried below the tube sheet there is a space left above the water -line, where there is neither steam nor water, and the heat is so great -that the ends of the tubes are burned and crystalized, and the tube -sheet is often cracked and broken by this excessive heat before the -steam is generated. The first difficulty is experienced in “the legs” -of the Portable Locomotive boiler—hence the general verdict of steam -users in favor of the round shell, many-tubed boiler. - - -PARTS OF THE TUBULAR BOILER. - -THE SHELL. This is the round or cylindrical structure which is commonly -described as the boiler, in which are inserted the braces and tubes, -and which sustains the internal strain of the pressure of the steam, -the action of the water within, and the fire without. - -THE DRUM. This part is sometimes called the dome, and consists of an -upper chamber riveted to the top of the boiler for the purpose of -affording more steam space. - -THE TUBE SHEETS. These are the round, flat flanged sheets forming the -two ends of the boiler, into which the tubes are fastened. - -THE MANHOLE COVER. This is a plate and frame commonly opening inwards -and large enough to admit a man into the interior of the boiler. These -openings are sometimes made on the top and sometimes at the end of the -boiler. Manhole openings in steam boilers should invariably be located -in the head of the boiler, except in rare cases that may arise, when -circumstances require it to be placed in the shell. The manhole, so -placed, will not materially reduce the strength of the boiler, and -from this position it can more readily be seen that the boiler is kept -in proper condition. The proper sizes for manholes are 9×5 and 10×16, -according to circumstances. These are amply large for general use and -no material advantage is gained by increasing them. - -THE HAND HOLE PLATES. These are similar arrangements to the manhole -cover, except as to size. They are made large enough to admit the hand -into the boilers for the purpose of removing sediment and they are also -used for the purpose of inspecting the interior of the boiler. Two are -usually put in each boiler, one front and one in the rear. - -THE BLOW OFF. This consists of pipes and a cock communicating with the -bottom of the boiler for the purpose of blowing off the boiler or of -running off the water when the former needs cleaning. - -[Illustration: THE TRIPLE DRAUGHT TUBULAR BOILER.—Fig. 34.] - - -THE TRIPLE DRAUGHT TUBULAR BOILER. - -This boiler, which is extensively used by the manufacturers of New -England, is, as will be seen by the illustration, of the horizontal -tubular class, and is essentially different from the well known type -only in the arrangement of the tubes. The method secures the passage -of the products of combustion through the same shell twice; forward -through a part of the tubes, and backwards through the remaining ones. -The manner of accomplishing this result can be best described by -explaining how a common tubular boiler may be remodelled so as to carry -out this principle. - -[Illustration: Fig. 35.] - -A cylindrical shell, as shown in Fig. 34—of sufficient size to encircle -about one-half of the tubes, is attached to _the outside of the rear -head_ below the water line, and extended backward to the back end of -the setting. The encircled tubes are lengthened and carried backward -to the same point; the extension is closed in and made to communicate -with the boiler proper; the inner tubes emerge to the flue leading to -the chimney and the old connection from the smoke arch is cut off. With -this arrangement, the outer tubes of the boiler—a cluster on each side -of the supplementary shell carry the products of combustion forward to -the front smoke arch, and the inner tubes carry them backward to the -chimney. - -Fig. 35 exhibits the boiler in half section and shows the course of the -heat products through _one_ of the outer tubes and returning through -the boiler by _one_ of the inner cluster. - -Fig. 36 (page 84) shows the boiler sectionally, over the bridge wall; -the _shaded_ tube ends exhibit the cluster which return the heat -products to the rear of the boiler, after being brought forward by the -two outer clusters which are left unshaded. - -This arrangement of the tubes gives several advantages: - -1. It enables an exceedingly high furnace temperature, without loss at -the chimney. - -2. By dividing the heat into these currents a more equal expansion and -contraction is secured. This is an important point secured. - -3. In this system the tubes are almost equally operative. - -4. The extra body of water immediately over the furnace is both an -element of safety and a reservoir of power. - -5. The outlet for the waste products of combustion is found in this -style of boiler in a more convenient position at _the rear end_ of the -boiler. - -6. The boiler being self-contained, can be used in places where height -of story is limited. - -[Illustration: Fig. 36.] - - - - -SPECIFICATION FOR 125 HORSE POWER BOILER. - - -_For one Horizontal Tubular Boiler_ 72 _inches diameter_ 18 -_feet long for_…………………_of_……… - -Type. - -The boiler to be of the Horizontal Tubular type with all castings and -mountings complete. - - -Dimensions. - -Boiler 72 inches diameter and 18 feet long. Each boiler to contain 90 -best lap welded tubes 3-1/2 inches diameter by 18 feet long, set in -vertical and horizontal rows with a space between them vertically and -horizontally of no less than one inch and one-quarter (1-1/4) except -central vertical space, which is to be three inches (3). No tube to -be nearer than two and one-half inches (2-1/2) to shell or boiler. -Holes through heads to be neatly chamfered off. All tubes to be set -by Dudgeon Expander and slightly flared at front end, turned over and -beaded down at back end. - - -Quality and Thickness of Steel Plates. - -Shell plates to be 1/2-inch thick of homogeneous steel of uniform -quality having a tensile strength of not less than 65,000 lbs. Name of -maker, brand and tensile strength to be plainly stamped on each plate. - -Heads to be of same quality as plates of shell in all particulars -3/4-inch thick. Bottom of shell to be of one plate, and no plate to be -less than 7 feet wide. Top of shell to be in three plates. All plates -planed before rolling, and all joints fullered not caulked. - - -Flanges. - -All flanges to be turned in a neat manner to an internal radius of not -less than two inches (2) and to be clear of cracks, checks or flaws. - - -Riveting. - -Boilers to be riveted with 3/4-inch rivet throughout. All girth seams -to be double riveted. All horizontal seams to be double riveted. Rivet -holes to be punched or drilled so as to come fair in construction. No -drift pins to be used in construction of the boilers. - - -Braces. - -All braces to be of the crowfoot pattern, one and one eighth (1-1/8) -inch diameter and the shortest to be no less than four feet (4) long -and of sufficient number for thorough bracing, and to bear uniform -tension. - - -Manholes, Hand Holes and Thimbles. - -One manhole in top of each boiler with heavy cast iron frame riveted on -middle of centre plate; one manhole near the bottom of each front head; -head reinforced with a wrought iron ring two inches (2) square, riveted -to heads with flush countersunk rivets two inches (2) pitch and to -have all the necessary bolts, plates, guards and gaskets; two six-inch -thimbles riveted to top of each boiler, each to have a planed face; -one heavy 6-inch flange on bottom of each boiler, 12 inches from back -end to centre of flange. There must be two braces, one on each side of -manhole in front head; also to have three braces opposite manhole on -back head below tubes. - - -Lugs. - -Four (4) lugs riveted on each side of boilers, of good and sufficient -size, with six one-inch rivets in each lug. - - -Castings. - -Each boiler to have a complete set of castings consisting of ornamental -flush fronts containing tube, fire and ash-pit doors, and provide -the best stationary grate bars as may be selected by buyer, with the -necessary fixtures, all bearing bars, britching plates, dead plates, -binder bars, back cleaning out doors with frames. Anchor bolts and -buck stays. The fire door to contain adjustable air opening and to be -protected with fire shields. One heavy cast iron arch over each boiler. - - -Testing. - -Boilers to be tested with a water pressure of 200 lbs. per square inch -and certificate of such test having been made shall be furnished with -boiler. Test of boiler to be under direction of such steam boiler -Insurance Company as may be selected by buyer. - - -Quality and Workmanship. - -All boilers to be made in the best workmanlike manner and all material -of their respective kinds to be of the best, and in strict accordance -with specification. - - -Fittings and Mountings. - -The boiler to be furnished with the following: One four inch heavy -mounted safety valve. One six inch flanged globe valve. Two two inch -best globe valves. Two two inch check valves. One eight inch dial -nickel plated steam gauge. One low water alarm gauge. One set of fire -irons for two boilers consisting of hoe, poker, slice bar and shovel. - - -Drawings. - -All drawings furnished for masons in setting the boilers. - - -Duty of Boiler. - -The boiler to develop 120 horse power and to work under a constant -pressure varying from 125 to 150 lbs. to the square inch. - -All rivets are to be 2-1/2 and 1-1/2 inch pitch. The pitch line of the -rivets to be not nearer 1-1/8 inches to the edge of the sheet. - -To be 8 lug plates for each boiler not less than 2 feet long, 8 inches -wide, and one inch thick. - -There shall be six 1 inch anchor rods running front to rear of each -boiler, in the brick work. - -These boilers and all their fronts, fittings and connections will be -subject to the inspection of………………… - - - - -MARKS ON BOILER PLATES. - - -Something has been said under another heading of the nature and -requisite quality of the materials entering into the structure of the -boiler. Too much emphasis cannot be laid upon the necessity for the use -of the very best iron and steel that can be manufactured, and the most -skillful and thorough workmanship that can be performed in constructing -the boiler. - -It is becoming the practice, both for land and marine boilers, for -boiler plate makers to furnish “test pieces” from each sheet or plate -that goes into the construction of a boiler, and a sheet showing the -tensile strength of each sheet or plate that enters into its make up. - -But irrespective of this practice each plate entering into boiler -construction will be found to have one of the following marks, which -designate its quality and method of manufacture. The name “Charcoal -Iron” is used because in its manufacture wood charcoal is employed -instead of mineral fuel. - -“Charcoal No. 1 Iron” (C. No. 1) is made entirely of charcoal iron. It -has a tenacity of 40,000 pounds per square inch in the direction of the -fibre. It is hard, but not very ductile, and should never be used for -flanging. - -“Charcoal Hammered No. 1 Shell Iron” (C. H. No. 1 S.), although not -necessarily hammered, has been worked up before it is rolled into -plates. It has a tenacity of 50,000 to 55,000 pounds per square inch in -the direction of the fibre. It is rather hard iron, and should not be -flanged. It is used for the outside shell of boilers. - -“Flange Iron” (C. H. No. 1 F.), is a ductile material which can be -flanged in every direction. It has a tenacity of 50,000 to 55,000 -pounds per square inch along the fibre. - -“Fire Box Iron” (C. H. No. 1 F. B.), is a harder quality, designed -especially to withstand the destructive effect of the impinging flame, -and is used for boxes and flue-sheets. - -The letters in the brackets exhibit the plate stamp. - -Cast iron and copper were used in an early day for steam boilers and -the former is still extensively used for certain forms of low pressure -steam heaters made for various purposes, such as green houses, etc. - - - - -CONSTRUCTION OF BOILERS. - - -In selecting a boiler, the most efficient design will be found to be -that in which _the greatest amount of shell surface is exposed to -direct heat_. It is the direct heating surface that does the bulk of -the work and every tendency to reduce it, either in the construction -or setting of the boiler, should be avoided. The smaller the amount of -surface enclosed by or in contact with the setting, the better results -will be obtained. - -A boiler with a bad circulation is the bane of an engineer’s existence. -Proper circulation facilities constitute one of the chief factors in -the construction of a successful and economical boiler. In tubular -boilers the best practice places the tubes in vertical rows, leaving -out what would be the centre row. The circulation is up the sides of -the boiler and down the centre. Tubes set zig-zag to break spaces -impede the circulation and are not considered productive of the best -results. - -The surface from which evaporation takes place should be made greater -as the steam pressure is reduced, that is to say, as the size of the -bubbles of steam become greater. To produce 100 lbs. of steam per hour -at atmospheric pressure this surface should not be less than 732 square -feet, which may be reduced to 146 square feet for steam at 75 lbs. -pressure, and to 73 feet for steam at a pressure of 150 lbs. It is for -this reason that triple-expansion engines can be worked with smaller -boilers than are required with engines using steam of lower pressure. -The amount of steam space to be permitted depends upon the volume -of the cylinders and the number of revolutions made per minute. For -ordinary engines it may be made a hundred times as great as the average -volume of steam generated per second. - -A volume of heated water in a boiler performs the same office in -furnishing a steady supply of steam as a fly-wheel does to an engine in -insuring uniformity of speed; hence the centre space of a boiler should -be ample, in order to take advantage of this reserve force. - - -QUALITY OF STEEL PLATES. - -Steel for boilers is always of the kind known as low steel, or -soft steel, and is, properly speaking, _ingot iron_, all of its -characteristics being those of a tenacious, bending, equal grained -iron, and quite different from true steels, such as knife blades, -cutting tools, etc., are composed of. Steel is rapidly displacing -iron in boiler construction, as it has greater strength for the same -thickness, than iron; and, except in rare instances, where the nature -of the water available for feed renders steel undesirable, iron should -not be used for making boilers, careful tests having shown it to be -vastly inferior to steel in many important features. - -Good boiler steel up to one-half inch in thickness should be capable -of being doubled over and hammered down on itself without showing any -signs of fracture, and above that thickness it should be capable of -being bent around a mandrel of a diameter equal to one and one-half -times the thickness of the plate, to an angle of 180 degrees without -sign of distress. Such bending pieces should not be less in length than -sixteen times the thickness of the plate. - -On this test piece the metal should show the following physical -qualities: - -Tensile strength, 55,000 to 65,000 pounds per square inch. - -Elongation, 20 per cent. for plates three-eighths inch thick or less. - -Elongation, 22 per cent. for plates from three-eighths to three-fourths -inch thick. - -Elongation, 25 per cent. for plates over three-fourths inch thick. - -The cross sectional area of the test piece should be not less than -one-half of one square inch, _i.e._, if the piece is one-fourth inch -thick, its width should be two inches; if it be one-half inch thick, -its width should be one inch. But for heavier material the width shall -in no case be less than the thickness of the plate. - -NICKEL STEEL BOILER PLATES. - -It has been found that the addition of about three per cent. (3.16 to -3.32) of nickel to ordinary soft steel produces most favorable results; -thus it has been shown by Riley that a particular variety of nickel -steel presents to the engineer _the means of nearly doubling boiler -pressures without increasing weight or dimensions_. - -In a recent experiment made with Bessemer steel rolled into -three-fourths inch plates from which a number of test specimens were -cut, the elastic limit was respectively 59,000 pounds and 60,000 -pounds. The ultimate tensile strength was 100,000 pounds and 102,000 -pounds, respectively. The elongation was 15-1/2 per cent. in each -specimen, and the reduction of area at fracture was 29-1/2 per cent. -and 26-1/2 per cent. respectively. These figures show that the elastic -limit and ultimate tensile strength was raised by the nickel alloy to -almost double the limits reached in the best grades of boiler plate -steel, and the elongation was reduced to a scarcely appreciable extent. - -The experiment had for its object, the reproduction, as nearly as -possible, of the alloy used in the nickel steel armor plate made at Le -Creusot, France, and the result was reported to the Secretary of the -Navy at Washington. The new plate showed a percentage of 3.16 nickel, -as against 3.32 for the imported plate. - - -RIVETING. - -When the materials are of best quality, then there only remains to -rivet and stay the boiler. _Riveting_ is of two kinds, single and -double. Fig. 37 shows the method of single riveting, and Figs. 38 and -39 show the plan and cross-section of double riveted sheets. - -[Illustration: Fig. 37.] - -_Double Riveting_ consists in making the joints of boiler work with -two rows of rivets instead of one—nearly always, horizontal seams -are double riveted as well as domes where they join upon the boiler. -Usually all girth seams,—those running round the body of the boiler, -are single riveted. The size of the rivets is in proportion to the -diameter of the boiler, being 5/8, 3/4 and 7/8 as required in the -specification. - -Rivet holes are made by punching or drilling, according to the material -in which they are made. In soft iron and mild steel they may safely be -punched, but in metal at all brittle the holes should be drilled. - -[Illustration: Fig. 38.] - -Rivets are driven by hand, by steam riveting machines or by an -improved pneumatic machine which holds the sheet together and strikes -a succession of light blows to form the head of the rivet while -hot. Rivets are made both of iron and steel, and there are certain -well-known brands of such excellent quality that they are almost -exclusively used in boiler work. - -A place where skill is shown in boiler construction is in laying out -the rivet holes, with a templet, so that the sheets come exactly -together with the holes so nearly opposite that the dreaded drift pin -does not have to be used. - -In these figures the letters P and p refer to the “pitch of the -rivets,” _i.e._, the part from centre to centre, and the dimensions -given at the sides indicate the amount of lap given in inches and -tenths of inches—the diameter of the rivet (1″) is also shown, and the -turned over portion of the shank of the rivet is shown by dotted lines. - -[Illustration: Fig. 39.] - -No riveted boiler work can be considered fairly proportioned unless the -strength of the plate between the rivets is fully equal to the strength -of the rivets themselves. A margin (or net distance from outside of -holes to edge of plate) equal to the diameter of the drilled hole has -been found sufficient. - -Rivets should be made of good charcoal iron or of a very soft mild -steel, running between 50,000 and 60,000 pounds tensile strength and -showing an elongation of not less than ninety per cent. in eight -inches, and having the same chemical composition as specified for -plates. - -A long rivet, holding thick plates together, is rarely tight except -immediately under the head. The heads are set and the centre cooled -before the hole is properly filled. If it is a very long rivet there is -a chance of the contraction fracturing the head of the rivet. In the -Forth Bridge, which is made of very heavy plate girders, the rivets, -first carefully fitted, were driven tight into the holes, the burr -around the holes were removed, and the ends of the rivets heated to a -sufficient degree to enable them to be closed over. - -A simple mathematical deduction shows that a circle seam has just -one-half the strain to carry as a longitudinal seam, under the same -pressure and with the same thickness of metal, hence the custom of -single riveting the former and double riveting the latter, or longwise -seams. - -DIFFERENT MODES OF RIVETING. - - +---------+----------+----------+-----------+ - | CHAIN | ZIG ZAG | TREBLE | UNEQUAL | - |RIVETING.| RIVETING.| RIVETING.| PITCHES. | - +---------+----------+----------+-----------+ - | O O | O | O O | O O O | - | | O | O | | - | O O | O | O O | O O | - | | O | O | | - | O O | O | O O | O O O | - | | O | O | | - | O O | O | O O | O O | - | | O | O | | - | O O | O | O O | O O O | - +---------+----------+----------+-----------+ - -In fig. 41 may be seen an example of zig-zag riveting. - -[Illustration: Fig. 41.] - -CAULKING.—By this is meant the closing of the edges of the seams of -boilers or plates. In preparing the seams for caulking, the edges are -first planed true inside and outside; and after the plates have been -riveted together, the edges are caulked or closed by a blunt chisel -about 1/4-inch thick at the edge, which should be struck with a 3 or -4-lb. hammer; sometimes one man doing the work alone and sometimes one -holding the chisel and another striking. - -_Fullering_ a boiler plate is done by a round-nosed tool, while -_caulking_ is executed by a sharper instrument. - -The thinnest plate which should be used in a boiler is one-fourth of an -inch, on account of the almost impossibility of caulking the seams of -thinner plates. - -It is a rule well known to all practical boiler makers that the thinner -the metal (compatible with due strength) the longer the life of the -boiler under its varying stresses and the better the caulking will -stand. - -STEEL RIVETS. - -Hitherto there has been some prejudice against steel rivets, and -while this may have some foundation when iron plates are used, it is -certainly baseless when steel plates are concerned. The United States -government has clearly demonstrated this. All the ships of the new navy -have steel boilers, riveted with steel rivets, and an examination of -the character of the material prescribed and the severity of the tests -to which it is subjected show that these steel-riveted steel boilers -are probably the best boilers ever constructed. - -United States Government Requirements for Boiler Rivets. - -They are subjected to the most severe hammer tests, such as flattening -out cold to a thickness of one-half the diameter, and flattening out -hot to a thickness of one-third the diameter. In neither case must they -show cracks or flaws. - -_Kind of Material._—Steel for boiler rivets must be made by either the -open-hearth or Clapp-Griffith process, and must not show more than .035 -of one per centum of phosphorus nor more than .04 of one per centum of -sulphur, and must be of the best quality in other respects. - -Each ton of rivets from the same heat or blow shall constitute a lot. -Four specimens for tensile tests shall be cut from the bars from which -the lot of rivets is made. - -_Tensile Tests._—The rivets for use in the longitudinal seams of boiler -shells shall have from 58,000 to 67,000 pounds tensile strength, with -an elongation of not less than 26 per centum; and all others shall have -a tensile strength of from 50,000 to 58,000 pounds, with an elongation -of not less than 30 per centum in eight (8) inches. - -_Hammer Test._—From each lot twelve (12) rivets are to be taken at -random and submitted to the following tests: - -Four (4) rivets to be flattened out cold under the hammer to a -thickness of one-half the diameter without showing cracks or flaws. - -Four (4) rivets to be flattened out hot under the hammer to a thickness -of one-third the diameter without showing cracks or flaws—the heat to -be the working heat when driven. - -Four (4) rivets to be bent cold into the form of a hook with parallel -sides, without showing cracks or flaws. - -_Surface Inspection._—Rivets must be true to form, free from scale, -fins, seams and all other unsightly or injurious defects. - -In view of the fact that the government is using many hundred tons of -these rivets, shown by the records of the tests to be vastly superior -to any iron rivet made, in all the essentials of a good rivet, it would -seem that it would benefit the boiler maker, the purchaser of the -boiler and also the maker of the rivet by adopting a standard steel -rivet to be used in all steel boilers. - - -BRACING OF STEAM BOILERS. - -The material of a boiler being satisfactory and the plates being -thoroughly and skillfully riveted there remains the important matter -of strengthening the boiler against the enormous internal pressure not -altogether provided for. - -[Illustration: Fig. 42.] - -To illustrate the importance of attention to this point it may be -remarked that a boiler eighteen feet in length by five feet in -diameter, with 40 four-inch tubes, under a head of 80 pounds of steam, -has a pressure of nearly 113 tons on each head, 1,625 tons on the shell -and 4,333 tons on the tubes, making a total of 6,184 tons on the whole -of the exposed surfaces. - -Not only is this immense force to be withstood, but owing to the fact -that the boiler grows weak with age—_a safety factor_ of six has been -adopted by inspectors, _i.e._, the boiler must be made six times as -strong as needed in every day working practice. - -[Illustration: Fig. 43.] - - -BRACES IN THE BOILER.—The proper bracing of flat surfaces -exposed to pressure, is a matter of the greatest importance, as the -power of resistance to bulging possessed by any considerable extent -of such a surface, made as they must be in the majority of cases of -thin plates, is so small that _practically the whole load has to be -carried by the braces_. This being the case, it is evident that as -much attention should be given to properly designing, proportioning, -distributing and constructing the brace as to any other portion of the -boiler. - -All flat surfaces should be strongly supported with braces of the best -refined iron, or mild steel, having a tensile strength of not less than -58,000 lbs. to the square inch. These braces must be provided with crow -feet or heavy angle iron properly distributed throughout the boiler. - -[Illustration: Fig. 44.] - -Fig. 42 shows the method usually followed in staying small horizontal -tubular boilers. The cut represents a 36-inch head and there are five -braces in each head: two short ones and three long ones. The braces -should be attached to shell and head by two rivets at each end. The -rivets should be of such size that _the combined area_ of their shanks -will be at least equal to the body of the brace, and their length -should be sufficient to give a good large head on the outside to -realize strength equal to the body of the brace. - -In boilers with larger diameters, 5 to 8 feet, stay ends are made of -angle or T iron; by this arrangement the stays can be placed further -apart, the angle irons very effectively staying the plate between the -stays, and thus affording more room in the body of the boiler. The size -of the stays have to be increased in proportion to the greater load -they have to sustain. See Fig. 43. - -In a 66-inch boiler it is proper to have not less than 10 braces in -each head, none under three feet in length, made of the best round iron -one inch in diameter, with ends of braces made of iron 2-1/2 × 1/2 -inches with three pieces of T iron riveted to head above the tubes to -which the braces are attached with suitable pins or turned bolts. See -Fig. 44. - - -STAYING OF FLAT SURFACES.—When boilers are formed principally of -flat plates, like low-pressure marine boilers, or the fire-boxes of -locomotive boilers, the form contributes nothing to the strength, which -must, therefore, be provided for by staying the opposite furnaces -together. Fig. 45 shows the arrangement of the stays in a locomotive -fire-box. They are usually pitched about 4 inches from centre to -centre, and are fastened into the opposite plates by screwing, as -shown, the heads being riveted over. Each stay has to bear the pressure -of steam on a square _aa_, and the sectional area of the stay must be -so chosen that the tensile strength will be sufficient to bear the -strain with the proper factor of safety. - -[Illustration: Fig. 45.] - -If the spaces between the stays are too great, or the plate too thin, -there is a danger of the structure yielding through the plate bulging -outwards between the points of attachment of the stays, thus allowing -the latter to draw through the screwed holes made in the plates. - -In designing boilers with stayed surfaces, care should be taken that -_the opposite plates connected by any system of stays should, as far as -possible, be of equal area_, otherwise there is sure to be an unequal -distribution of load in the stays, some receiving more than their -proper share, and moreover, the least supported plate is exposed to the -danger of buckling. - - -RULE FOR FINDING PRESSURE OR STRAIN ON BOLTS. - -The absolute stress or strain on a flat surface of a steam boiler, -which is carried by the stays, can be easily determined by a simple -rule: - -Choose 3 stays as A B C in Fig. 46, measure from A to B _in inches_, -and from A to C. Multiply these two numbers together and the result -is the number of square inches of surface depending upon one bolt for -supporting strength. - -EXAMPLE. - -Suppose the stays measure from center to center 5 inches each way with -steam at 80 lbs., then - -5 × 5 = 25 × 80 = 2,000 lbs. borne by 1 stay. - -NOTE. - -The pressure on the surface does not include the space occupied by the -area of the stay bolt, hence, to be absolutely correct that must be -deducted. - -[Illustration: Fig. 46.] - - -GUSSET STAYS. - -The flat ends of cylindrical boilers are, especially in marine boilers, - -stayed to the round portions of triangular plates of iron called gusset -stays. These are simply pieces of plate iron secured to the boiler -front or back, near the top or bottom, by means of two pieces of angle -iron, then carried to the shell plating, and again secured by other -pieces of angle bar. This arrangement is shown in Fig. 47. - -[Illustration: Fig. 47.] - - -PALM STAYS.—These are shown in Fig. 48, and are often used in the same -position as a gusset stay; that is, from the back or front end of the -boiler to the shell plates; they are sometimes used to stay the curved -tops of combustion chambers. - -[Illustration: Fig. 48.] - -The two opposite ends are also stayed together by long bar stays, -running the whole length of the boiler, it is dangerous, however, to -trust too much to the latter class of stays; for, in consequence of the -alternate expansion and contraction which takes place every time the -boiler is heated and cooled, they have a tendency to work loose at the -joints; and if the portion of the boiler in which they are situated -should happen to be hotter than the outside shell, they have a tendency -to droop and are then perfectly useless. - - -RIVETED OR SCREW STAYS. - -[Illustration: Fig. 49.] - -In addition to palm and gusset stays, there are in use riveted or -screwed stays, as shown in Fig. 49. - -This would not answer in furnaces, owing to the burning off of the -heads, hence driven stays are used there. - -[Illustration: Fig. 50.] - -These screwed stays, shown in Fig. 50, are used (in marine and similar -boilers) between the combustion chamber back and boiler back and also -between the sides of the combustion chambers. - -The general plan is to have a large nut and washer inside and outside -the boiler with the outside washer considerably larger than the inside, -so as to hold more efficiently the back and front ends together. - -In marine boilers it is customary to place the stays 15 to 18 inches -apart for ease of access to the parts of the boiler, and to make them -of 2-1/4 to 2-1/2 inch iron of the best quality. - - -INSPECTOR’S RULES RELATING TO BRACES IN STEAM BOILERS, ALSO TO BE -OBSERVED BY ENGINEERS. - -Where flat surfaces exist, the inspector must satisfy himself that the -spacing and distance apart of the bracing, and all other parts of the -boiler, are so arranged that all will be of not less strength than the -shell, and he must also after applying the hydrostatic test, thoroughly -examine every part of the boiler. - -No braces or stays employed in the construction of marine boilers shall -be allowed a greater strain than six thousand pounds per square inch -of section, and no screw stay bolt shall be allowed to be used in the -construction of marine boilers in which salt water is used to generate -steam, unless said stay bolt is protected by a socket. But such screw -stay bolts, without sockets, may be used in staying the fire boxes -and furnaces of such boiler, and not elsewhere, when fresh water is -used for generating steam in said boiler. Water used from a surface -condenser shall be deemed fresh water. And no brace or stay bolt used -in a marine boiler will be allowed to be placed more than eight and -one-half inches from centre to centre, except that flat surfaces, -other than those on fire boxes, furnaces and back connections, may -be reinforced by a washer or =T= iron of such size and thickness as -would not leave such flat surface unsupported at a greater distance, -in any case, than eight and one-half inches, and such flat surface -shall not be of less strength than the shell of the boiler, and able to -resist the same strain and pressure to the square inch, and no braces -supporting such flat reinforced surfaces, will be allowed more than 16 -inches apart. - -In allowing the strain on a screw stay bolt, the diameter of the same -shall be determined by the diameter at the bottom of the thread. Many -State laws and City ordinances allow a strain of seven thousand five -hundred pounds per square inch of section on good bracing without -welds. The following table gives the safe load of round iron braces or -stays. - -DIAMETER OF BRACE. - - ----------+----+----+----+----+----+------+------+------+------+----- - Tensile | | | | | | | | | | - strength | | | | | | | | | | - per square|1/2″|5/8″|3/4″|7/8″| 1″ |1-1/8″|1-1/4″|1-1/2″|1-3/4″| 2″ - inch of | | | | | | | | | | - section | | | | | | | | | | - allowed | | | | | | | | | | - ----------+----+----+----+----+----+------+------+------+------+----- - 5000 | 981|1533|2208|3006|3927| 4970 | 6136 | 8835 |12026 |15708 - 6000 |1178|1840|2650|3607|4712| 5964 | 7363 |10602 |14431 |18849 - 7000 |1374|2567|3092|4209|5497| 6958 | 8590 |12369 |16837 |21991 - 7500 |1472|2750|3313|4509|5890| 7455 | 9204 |13253 |18039 |23562 - ----------+----+----+----+----+----+------+------+------+------+----- - -SHOP NAMES FOR BOILER BRACES.—1. Gusset brace (fig. 47). 2. Crowfoot -brace. 3. Jaw brace (fig. 44). 4. Head to head brace (fig. 50). These -shop terms refer to braces used in the tubular form of boiler. - -A STAY AND A BRACE in a steam boiler fulfil the same office, that of -withstanding the pressure exerted outward of the expanded and elastic -steam. - -SOCKET BOLTS are frequently used instead of the screw stay between the -inside and outside plates that form the centre space. Socket bolts are -driven hot the same as rivets. - -The method of bracing with =T= bars is considered the best; the bars -make the flat surface rigid and unyielding even before the brace is -applied. The braces should be spaced about 8 inches apart on the =T= -bar and 7 inches from the edge of the flange =T= the bar should be 4″ -× 4-1/2″ =T= iron and riveted to the head or flat surface with 11/16″ -rivets spaced 4-1/2 inches apart. - -HOLLOW STAY BOLTS are used in locomotive fire boxes to show when -fracture has occurred by permitting an escape of steam or water. - -The flange of a boiler head 1/2″ thick will amply support 6 inches from -the edge of the flange. - -A radius of 2 inches is ample for bend of flange on the head. The lower -braces should be started 6 inches above the top row of tubes. Braces -should be fitted so as to have a straight pull, _i.e._ parallel with -the boiler shell. The heads of the boiler should be perfectly straight -before the braces are fitted in place. Gusset brace plates should not -be less than 30 inches long and 14 inches wide. Braces are best made of -1 inch =O= iron of highest efficacy with tensile strength of not less -than 58,000 lbs. to the square inch. - -[Illustration: Fig. 51.] - -The riveted stay shown in Fig. 51, consists of a long rivet, passed -through a thimble or distance piece of wrought iron pipe placed between -plates, to be stayed together, and then riveted over in the usual -manner. - -An ingenious device is in use to show when a bolt has broken. A small -hole is drilled into the head, extending a little way beyond the plate, -and as experience shows that the fracture nearly always occurs _next to -the outside plate_, that is the end taken for the bored out head: when -the bolt is broken the rush of steam through the small hole shows the -danger without causing serious disturbance. - -Even where the best of iron is used for stay bolts they should never be -exposed to more than 1/10th or 1/12th their breaking strength. - -The stays should be well fitted, and each one carefully tightened, and, -as far as possible each stay in a group _should have the same regular -strain upon it_—if the “pull” all should come on one the whole are -liable to give way. - -DIMENSIONS AND SHAPE OF ANGLE AND T IRON. - -[Illustration: Fig. 52.] - -The condition of a boiler can be learned by tapping on the sheets, -rivets, seams, etc., to ascertain whether there are any broken stays, -laminated places, broken rivets, etc. - -[Illustration: Fig. A.] - -[Illustration: Fig. B.] - -Fig. A represents the method of preparing testing pieces of boiler -plate, for the machines prepared specially to measure their elongation -before breaking, and also the number of pounds they will bear -stretching before giving way. Fig. B exhibits the same with reference -to the brace and other =O= iron. - - -RULES AND TABLES - -FOR DETERMINING AREAS AND CALCULATING THE CONTENTS OF STEAM AND WATER -SPACES IN THE STEAM BOILER. - -In order to ascertain the number of braces, which are necessary to -strengthen that part of the boiler head, which is not stayed by the -tubes, it is first necessary to know its area; the part to be stayed is -_a segment of a circle_. - -_The length of the segment_ is measured above the top row of the tubes, -and its _height or width_ is equal to the distance from the top of the -tubes to the top of the boiler shell. - -Since, however, part of this segment is braced by the boiler shell, -and also by the top row of the tubes, it has been generally agreed -that the length of the segment should be measured two inches above the -tubes, and the height or width, should be measured from a line, drawn -two inches above the tubes, to a point within three inches from the top -of the boiler shell, as shown in the illustration by the dotted line. -Thus, referring to Fig. D, the length of the segment is equal to l, and -the height is equal to h. - -RULE. The area of a segment may be obtained, very approximately, by -_dividing the cube of the width (or height) by twice the length of -the chord, and adding to the quotient the product of the width into -two-thirds of the chord_. - -EXAMPLE. If we suppose the height h of the segment in Fig. D to be -equal to 18 inches, and the length l to be equal to 48 inches, we have - -18³ ÷ (48 × 2) + (48 × 2/3 × 18) = 60.7 + 576.0 = 636.7 square inches. - -[Illustration: Fig. C. Fig. D.] - -In order to calculate the contents of the steam and water spaces of a -boiler, the same rule, as above, may be employed. The volume of the -steam space may be readily obtained by the above rule, _taking the -distance from the water level to the top of the shell for the height, -and the diameter of the shell, measured at the water line, for the -length of the segment lines_. - -The area of the segment thus found, expressed in square inches, divided -by 144, and multiplied by the length of the boiler in feet, is equal to -_the steam space, in cubic feet_, this result is slightly reduced by -the space occupied by the braces. - -In order to find the volume of the water space, it is first necessary -to _find the total area of the boiler head_, and this _minus the area -of the segment above the water line_, is equal to the area of the -segment below the water line. From this must also be subtracted _the -combined cross sectional area of the tubes_. - -Thus, the rule for finding the volume of the steam space in cubic feet. - -1. _Find the area of the segment of the boiler head, above the water -line, in square inches._ - -2. _Divide this by 144, and multiply the quotient by the length of the -boiler in feet._ - -To find the volume of the waterspace in cubic feet. - -1. _Find the area of the boiler head in square inches._ - -2. _Multiply the square of the outside diameter of one tube by .7854, -and multiply this by the number of tubes, and add to the product, the -area of the segment above the waterline_. - -3. _Subtract 2 from 1, and divide the remainder by 144._ - -4. _Multiply the quotient by the length of the boiler in feet._ - -To find the number of braces, necessary for the flat surface above the -tubes. - -1. _Find the area of the segment of the boiler head, which is to be -braced, in square inches._ - -2. _Multiply the area, thus found, by the steam pressure in pounds per -square inch._ - -3. _Multiply the cross sectional area of one brace by the number of -pounds, which it is allowed to carry, per square inch of section._ - -4. _Divide product 2 by product 3, and the result is the number of -braces, required for the head_. - -Table No. 1 gives the total area in square inches. No. 2, areas to -be braced. No. 3, number of braces of one inch round iron required, -allowing seven thousand five hundred pounds per square inch of section -at one hundred pounds steam pressure. - -Table No. 3 will be found of more practical use than Table 2, for it -gives directly the number of braces required in any given boiler, -instead of the area to be braced. It was calculated from Table 2. The -iron used in braces will safely stand a continuous pull of 7,500 -pounds to the square inch, which is the figure used in computing the -foregoing table. A round brace an inch in diameter has a sectional area -of .7854 of an inch, and the strain that it will safely withstand is -found by multiplying .7854 by 7,500, which gives 5,890 pounds as the -safe working strain on a brace of one-inch round iron. - -In a 60-inch boiler, whose upper tubes are 28 inches below the shell, -the area to be braced is, according to table 2, 930 square inches. If -the pressure at which it is to be run is 100 pounds to the square inch, -the entire pressure on the area to be braced will be 93,000 pounds, and -this is the strain that must be withstood by the braces. As one brace -of inch-round iron will safely stand 5,890 pounds, the boiler will need -as many braces as 5,890 is contained in 93,000, which is 15.8. That is, -16 braces will be required. The table is made out on the basis of 100 -lbs. pressure to the square inch, because that is a very convenient -number. - -TABLE NO. 1. TOTAL AREA ABOVE TUBES OR FLUES. - -(SQUARE INCHES.) - - ----------+----------------------------------------- - Height | DIAMETER OF BOILER IN INCHES. - from tubes+-----+-----+-----+-----+-----+-----+----- - to shell.| 36 | 42 | 48 | 54 | 60 | 66 | 72 - ----------+-----+-----+-----+-----+-----+-----+----- - 15 | 389 | | | | | | - 16 | 419 | | | | | | - 17 | 458 | 526 | | | | | - 18 | | 566 | 620 | 667 | | | - 19 | | 608 | 667 | 720 | | | - 20 | | 650 | 714 | 770 | 824 | | - 21 | | | 756 | 824 | 882 | | - 22 | | | 808 | 878 | 937 | | - 23 | | | | 930 | 996 |1059 | - 24 | | | | 982 |1056 |1121 | - 25 | | | |1037 |1116 |1184 | - 26 | | | |1090 |1209 |1252 |1324 - 27 | | | |1145 |1234 |1316 |1394 - 28 | | | | |1291 |1381 |1465 - 29 | | | | |1352 |1445 |1536 - 30 | | | | |1414 |1511 |1608 - 31 | | | | | |1576 |1674 - 32 | | | | | |1641 |1746 - 33 | | | | | | |1818 - 34 | | | | | | |1896 - ----------+-----+-----+-----+-----+-----+-----+----- - -TABLE 2. AREAS TO BE BRACED. (SQUARE INCHES.) - - ----------+----------------------------------------- - Height | DIAMETER OF BOILER IN INCHES. - from tubes+-----+-----+-----+-----+-----+-----+----- - to shell.| 36 | 42 | 48 | 54 | 60 | 66 | 72 - ----------+-----+-----+-----+-----+-----+-----+----- - 15 | 206 | | | | | | - 16 | 235 | | | | | | - 17 | 264 | 297 | | | | | - 18 | | 331 | 365 | 396 | | | - 19 | | 316 | 404 | 439 | | | - 20 | | 401 | 444 | 483 | 519 | | - 21 | | | 485 | 528 | 568 | | - 22 | | | 526 | 574 | 618 | | - 23 | | | | 620 | 668 | 714 | - 24 | | | | 667 | 720 | 769 | - 25 | | | | 714 | 772 | 825 | - 26 | | | | 761 | 824 | 882 | 937 - 27 | | | | 809 | 877 | 940 | 998 - 28 | | | | | 930 | 998 |1061 - 29 | | | | | 983 |1056 |1124 - 30 | | | | |1037 |1115 |1187 - 31 | | | | | |1174 |1252 - 32 | | | | | |1234 |1317 - 33 | | | | | | |1382 - 34 | | | | | | |1447 - ----------+-----+-----+-----+-----+-----+-----+----- - -TABLE 3. NUMBER OF BRACES REQUIRED, AT 100 LBS. PRESSURE. - - ----------+----------------------------------------- - Height | DIAMETER OF BOILER IN INCHES. - from tubes+-----+-----+-----+-----+-----+-----+----- - to shell.| 36 | 42 | 48 | 54 | 60 | 66 | 72 - ----------+-----+-----+-----+-----+-----+-----+----- - 15 | 3.5 | | | | | | - 16 | 4.0 | | | | | | - 17 | 4.5 | 5.0 | | | | | - 18 | | 5.6 | 6.2 | 6.7 | | | - 19 | | 6.2 | 6.9 | 7.5 | | | - 20 | | 6.8 | 7.5 | 8.2 | 8.9 | | - 21 | | | 8.2 | 9.0 | 9.6 | | - 22 | | | 8.9 | 9.8 |10.5 | | - 23 | | | |10.5 |11.3 |12.1 | - 24 | | | |11.3 |12.2 |13.1 | - 25 | | | |12.1 |13.1 |14.0 | - 26 | | | |12.9 |14.0 |15.0 |15.9 - 27 | | | |13.7 |14.9 |16.0 |16.9 - 28 | | | | |15.8 |16.9 |18.0 - 29 | | | | |16.7 |17.9 |19.1 - 30 | | | | |17.6 |18.9 |20.2 - 31 | | | | | |19.9 |21.3 - 32 | | | | | |21.0 |22.4 - 33 | | | | | | |23.5 - 34 | | | | | | |24.9 - ----------+-----+-----+-----+-----+-----+-----+----- - -In Table 2 this calculation has been made for all sizes of boilers that -are ordinarily met with. The area to be braced has been calculated -as above in each case, the two-inch strip above the tubes, and the -three-inch strip around the shell being taken into account. As an -example of its use, let us suppose that upon measuring a boiler we find -that its diameter is 54 inches, and that the distance from the upper -tubes to the top of the shell is 25 inches. Then by looking in the -table under 54″ and opposite 25″ we find 714, which is the number of -square inches that requires staying on each head. - - -BOILER TUBES. - -TABLE. - -_Dimensions of Lap Welded Boiler Tubes._ - - --------------+---------+---------- - Size outside | Wire |Weight per - diameter. | Gauge. | foot. - --------------+---------+---------- - 1 inch. | 15 | 0.708 - 1-1/4 „ | 15 | 0.9 - 1-1/2 „ | 14 | 1.250 - 1-3/4 „ | 13 | 1.665 - 2 „ | 13 | 1.981 - 2-1/4 „ | 13 | 2.238 - 2-1/2 „ | 12 | 2.755 - 2-3/4 „ | 12 | 3.045 - 3 „ | 12 | 3.333 - 3-1/4 „ | 11 | 3.958 - 3-1/2 „ | 11 | 4.272 - 3-3/4 „ | 11 | 4.590 - 4 „ | 10 | 5.320 - 4-1/2 „ | 10 | 6.010 - 5 „ | 9 | 7.226 - 6 „ | 8 | 9.346 - 7 „ | 8 | 12.435 - 8 „ | 8 | 15.109 - 9 „ | 7-1/2| - 10 „ | 6-1/2| - --------------+---------+---------- - - -The above is the regular manufactures’ list of sizes and weights. - -NOTE. - -Boiler tubes are listed and described from the _outside diameter_. This -should be noted, as gas-pipe is described from the _inside diameter_. -Thus a 1-inch gas-pipe is nearly 1-1/4 outside diameter while a 1-inch -boiler tube is exactly one inch. Another difference between the two -consists in the fact that the outside of boiler tubes is rolled smooth -and even; gas-pipe is left comparatively rough and uneven. - -When the boiler tubes are new and properly expanded there is a large -reserve or surplus of holding power for that part of the tube sheet -supported by them, this has been proved by experiment made by chief -engineer W. H. Stock, U. S. N., as shown in the following - -TABLE OF HOLDING POWER OF BOILER TUBES. - - --------------+--------+---------+-------+-------------------------- - Outside |Area of |Thickness|Strain | - diameter | cross | of tube | in | Method of Fastening. - of end of tube|section | plate .|pounds.| - where fracture|of body | |Mean | - took place. |of tube.| |result.| - --------------+--------+---------+-------+-------------------------- - Inches. |Sq. ins.| Inches. |Pounds.| - 2-5/8 | .981 | 7/16 | 22650 |Expanded by Dudgeon tool, - | | | | end riveted over. - 2-5/8 | .981 | 7/16 | 22150 |Expanded by Dudgeon tool, - | | | | end partly riveted over. - 2-3/8 | .981 | 3/8 | 25525 |Expanded by Dudgeon tool, - | | | | end riveted over. - 2-3/8 | .981 | 3/8 | 29675 |Expanded by Dudgeon tool, - | | | | ferruled, not riveted - | | | | over. - 2-3/8 | .981 | 3/8 | 13050 |Simply expanded by Dudgeon - | | | | tool. - --------------+--------+---------+-------+-------------------------- - -Mr. C. B. Richards, consulting engineer at Colt’s Armory at Hartford, -Conn., made some experiments as to the holding power of tubes in -steam boilers, with the following results: The tubes were 3 inches -in external diameter, and 0.109 of an inch thick, simply expanded -into a sheet 3/8 of an inch thick by a Dudgeon expander. The greatest -stress without the tubes yielding in the plate was 4,500 pounds, and -at 5,000 pounds was drawn from the sheet. These experiments were -repeated with the ends of the tubes which projected through the sheet -three-sixteenths of an inch, being flared so that the external diameter -in the sheet was expanded to 3.1 inches. The greatest stress without -yielding was 18,500 pounds; at 19,000 pounds yielding was observed; and -at 19,500 pounds it was drawn from the sheet. The force was applied -parallel to the axis of the tube, and the sheet surfaces were held at -right angles to the tube axis. - -NOTE. - -When the tube sheet and tube ends near the sheet become coated with -scale or the tubes become overheated, the holding power of the tubes -becomes largely reduced, and caution must be used in having the tube -ends re-expanded and accumulated scale removed. - -NOTE 2.—In considering the stress or strain upon the expanded -or riveted over ends of a set of boiler tubes, it may be remembered -that the strain to be provided against is only that coming upon tube -plate, exposed to pressure, _between the tube ends_—the space occupied -by the tubes has no strain upon it. - -The gauge to be employed by inspectors to determine the thickness of -boiler plates will be any standard American gauge furnished by the -Treasury Department. - -All samples intended to be tested on the Riehle, Fairbanks, Olson, or -other reliable testing machine, must be prepared in form according to -the following diagram, viz.: eight inches in length, two inches in -width, cut out their centres as indicated. - -[Illustration: Fig. E.] - - -PORTIONS OF THE MARINE BOILER WHICH BECOME THIN BY WEAR. - -These are generally situated, 1st, at or a little above the line of -fire bars in the furnace; 2d, the ash pits; 3d, combustion chamber -backs; 4th, shell at water line; 5th, front and bottom of boiler. - -The thinning can usually be detected by examination, sounding with a -round nosed hammer, or drilling small holes in suspected parts not -otherwise accessible for examination. - - - - -EXAMPLES OF CONSTRUCTION AND DRAWING - - - +--------+--------+---------+---------+ - | _d_ | _t_ | _d_ | _t_ | - +--------+--------+---------+---------+ - | _9/16″_| _1/4″_ | _15/16″_| _5/8″_ | - +--------+--------+---------+---------+ - |_11/16″_| _5/16″_|_1-1/16″_| _3/4″_ | - +--------+--------+---------+---------+ - | _3/4″_ | _3/8″_ |_1-1/8″_ | _7/8_ | - +--------+--------+---------+---------+ - | _7/8″_ | _1/2″_ |_1-3/16″_| _1″_ | - +--------+--------+---------+---------+ - _d_ = DIAM. OF RIVET. - - _t_ = THICKNESS OF PLATE. - -The small table above is of use in this and the four succeeding pages; -in all places in the drawings where “d” is used it indicates _the -diameter of the rivet_; “t” means _the thickness of the plate_; “p” -stands for _pitch_. The table also shows the proportion of rivet to the -plate—thus, a 1/4-inch plate requires a 9/16 rivet, etc. - -It is recommended, in view of the increased disposition on the part of -official examiners to test the applicant’s knowledge of drawing, for -any one interested, to redraw to a _full size_ all the rivets, plates, -and methods of joining the two contained on pages 113-116. - -[Illustration: Fig. 53.] - -[Illustration: Fig. 54.] - -The figures 53 to 60 will be understood without much explanation. - -In figures 53 and 54 _the cup head, the conical head and pan head -rivets_ are shown. - -Figs. 55 and 56 exhibit the details (and drawings) of single and double -riveting. Where the cut reads p = (2-1/2)d, it means that the distance -from the centre of one rivet to the centre of the next shall be 2-1/2 -the diameter of the rivet, see example, page 115. - -[Illustration: Fig. 55.] - -[Illustration: Fig. 56.] - -EXAMPLE. - -If the size of the rivet used is 7/8ths, then 7/8 × 2-1/2 = 2-2/10 -inches nearly, and this gives the proportionate strength of the plate -and the rivet, see page 113. - -[Illustration: Fig. 57.] - -Figs. 57, 58, 59 and 60 show quite clearly the joints and rivet work -done in locomotive and marine work. Fig. 60 shows method of riveting 3 -plates, A, B, and C, together. - -[Illustration: Fig. 58.] - -[Illustration: Fig. 59.] - -[Illustration: Fig. 60.] - - -RULE FOR SAFE INTERNAL PRESSURE - -The safe internal pressure on cylindrical shells is found according to -the following rule, which has been adopted by the United States Board -of Supervising Inspectors, and any boiler shell not found in the tables -can be determined by this rule. - -RULE.—Multiply one-sixth of the lowest tensile strength found stamped -on any plate in the cylindrical shell by the thickness—expressed -in inches or parts of an inch—of the thinnest plate in the same -cylindrical shell, and divide by the radius or half diameter—also -expressed in inches—and the result will be the pressure allowable per -square inch of surface for single riveting, to which add twenty per -centum for double riveting. - -The hydrostatic pressure applied, under this table and rule, must be in -the proportion of one hundred and fifty pounds to the square inch, to -one hundred pounds to the square inch of the working pressure allowed. - -EXAMPLE. - -What pressure should be allowed to be carried on a boiler 60″ diameter, -made of plates 3/8″ thick, having a tensile strength of 60,000 pounds? -Now then: - - 6)60,000 - ------ - 10,000 - 3 - ------ - 8)30,000 - ------ - Half diam. 30)3750(125. lbs.--if single riveted. - 30 - ---- - 75 - 60 - ---- - 150 125 + 25 lbs. (20 feet) = 150 for - 150 double riveted. - -TABLES SAFE INTERNAL PRESSURE. - - ----------+---------+---------------+---------------+--------------- - | | Pressure. | Pressure. | Pressure. - | +-------+-------+-------+-------+-------+------- - Diameter |Thickness|Single |Double |Single |Double |Single |Double - of | of |Riveted|Riveted|Riveted|Riveted|Riveted|Riveted - Boiler. | Plates. +-------+-------+--------+------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - ----------+---------+-------+-------+-------+-------+-------+------- - 36 Inches.| .21 | 87.5 |105. | 97.21 |116.65 |106.94 |128.3 - | .23 | 95.83 |114.99 |106.47 |127.76 |117.12 |140.54 - | .25 |104.16 |124.99 |115.74 |138.88 |127.31 |152.77 - | .26 |108.33 |129.99 |120.37 |144.44 |132.4 |158.88 - | .29 |120.83 |144.99 |134.25 |161.11 |147.68 |177.21 - | .33 |137.5 |165. |152.77 |183.32 |168.05 |201.66 - | .35 |145.83 |174.99 |162.03 |194.43 |178.23 |213.87 - | .375 |156.25 |187.5 |173.61 |208.33 |190.97 |229.16 - +---------+-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .21 |116.66 |139.99 |126.38 |151.65 |136.11 |163.33 - | .23 |127.77 |153.32 |138.41 |166.09 |149.07 |178.88 - | .25 |138.88 |166.65 |150.46 |180.55 |162.03 |194.43 - | .26 |144.44 |173.32 |156.48 |187.77 |168.51 |202.21 - | .29 |161.11 |193.33 |174.53 |209.43 |187.90 |225.48 - | .33 |183.33 |219.99 |198.61 |238.33 |213.88 |256.65 - | .35 |194.44 |233.32 |210.64 |252.76 |226.84 |272.20 - | .375 |208.33 |249.99 |225.69 |271.82 |243.05 |291.66 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 40 Inches.| .21 | 78.75 | 94.50 | 87.49 |104.98 | 96.24 |115.48 - | .23 | 86.25 |103.5 | 95.83 |114.99 |105.41 |126.49 - | .25 | 93.75 |112.5 |104.16 |124.99 |114.58 |137.49 - | .26 | 97.5 |117. |108.33 |129.99 |119.16 |142.99 - | .29 |108.75 |130.5 |120.83 |144.99 |132.91 |159.49 - | .3125 |117.18 |140.61 |130.2 |156.24 |143.22 |171.86 - | .33 |123.75 |148.5 |137.49 |164.98 |151.24 |181.48 - | .35 |131.25 |157.5 |145.83 |174.99 |160.41 |192.49 - | .375 |140.62 |168.74 |156.24 |187.48 |171.87 |206.24 - +---------+-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,0000 Tensile|70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .21 |105. |126. |113.74 |136.48 |122.49 |146.98 - | .23 |115. |138. |124.58 |149.49 |134.16 |160.99 - | .25 |125. |150. |135.41 |162.49 |145.83 |174.99 - | .26 |130. |156. |140.83 | 68.99 |151.66 |181.99 - | .29 |145. |174. |157.08 |188.49 |169.16 |202.99 - | .3125 |156.25 |187.45 |169.27 |203.12 |182.29 |218.74 - | .33 |165. |198. |178.74 |214.48 |192.49 |230.98 - | .35 |175. |210. |189.58 |227.49 |204.16 |244.99 - | .375 |187.5 |225. |203.12 |243.74 |218.74 |262.48 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 42 Inches.| .21 | 75. | 90.00 | 83.32 | 99.99 | 91.66 |109.99 - | .23 | 82.14 | 98.56 | 91.23 |109.51 |100.39 |120.46 - | .25 | 89.28 |107.13 | 99.2 |119.04 |109.12 |130.94 - | .26 | 92.85 |111.42 |103.17 |123.8 |113.49 |136.18 - | .29 |103.57 |124.28 |115.07 |138.08 |126.57 |151.85 - | .3125 |111.6 |133.92 |124. |148.8 |136.4 |163.68 - | .33 |117.85 |141.42 |130.94 |157.12 |144.04 |172.84 - | .35 |125. |150. |138.88 |166.65 |152.77 |183.32 - | .375 |133.92 |160.7 |148.8 |178.56 |163.68 |196.40 - +---------+-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .21 |100. |120. |108.33 |129.99 |116.66 |139.99 - | .23 |109.52 |131.42 |118.65 |142.38 |127.77 |153.32 - | .25 |119.04 |142.84 |128.96 |154.75 |138.88 |166.65 - | .26 |123.8 |148.56 |134.12 |160.94 |144.44 |173.32 - | .29 |138.09 |165.7 |149.6 |179.52 |161.11 |193.33 - | .3125 |148.74 |178.56 |161.2 |193.44 |173.61 |208.23 - | .33 |157.14 |188.56 |170.23 |204.27 |183.33 |219.99 - | .35 |166.66 |199.99 |180.55 |216.66 |194.44 |233.32 - | .375 |178.57 |214.28 |193.45 |232.14 |208.33 |249.99 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 48 Inches.| .21 | 65.62 | 78.74 | 72.91 | 87.49 | 80.2 | 96.24 - | .23 | 71.87 | 86.24 | 79.85 | 95.82 | 87.84 |105.4 - | .25 | 78.12 | 93.74 | 86.8 |104.16 | 95.48 |114.57 - | .26 | 81.25 | 97.50 | 90.27 |108.32 | 99.3 |119.16 - | .29 | 90.62 |108.74 |100.69 |120.82 |110.76 |132.91 - | .3125 | 97.65 |117.18 |108.5 |130.2 |119.35 |143.22 - | .33 |103.12 |123.74 |114.58 |137.49 |126.04 |151.24 - | .35 |109.37 |131.24 |121.52 |145.82 |133.67 |160.4 - | .375 |117.18 |140.61 |130.2 |156.24 |143.22 |171.86 - +---------+-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .21 | 87.49 |104.98 | 94.79 |113.74 |102.08 |122.49 - | .23 | 95.83 |114.99 |103.81 |124.57 |111.8 |133.16 - | .25 |104.16 |124.99 |112.84 |135.4 |121.52 |145.82 - | .26 |108.33 |129.99 |117.36 |140.83 |126.38 |151.65 - | .29 |120.83 |144.99 |130.9 |157.08 |140.97 |169.16 - | .3125 |130.21 |156.25 |141.05 |169.26 |151.9 |182.28 - | .33 |137.5 |165. |148.95 |178.74 |160.41 |192.49 - | .35 |145.83 |174.99 |157.98 |189.57 |170.13 |204.14 - | .375 |156.25 |187.50 |169.27 |203.12 |182.29 |218.74 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 54 Inches.| .21 | 58.33 | 69.99 | 64.81 | 77.77 | 71.29 | 85.54 - | .23 | 63.88 | 76.65 | 70.98 | 85.17 | 78.08 | 93.69 - | .25 | 69.44 | 83.32 | 77.16 | 92.52 | 84.87 |101.84 - | .26 | 72.22 | 86.66 | 80.24 | 96.28 | 88.27 |105.92 - | .29 | 80.55 | 96.66 | 89.5 |107.40 | 98.45 |118.14 - | .3125 | 86.8 |104.16 | 96.44 |115.72 |106.09 |127.30 - | .33 | 91.66 |109.99 |101.84 |122.22 |112.03 |134.43 - | .35 | 97.22 |116.66 |108.02 |129.62 |118.82 |142.58 - | .375 |104.16 |124.99 |115.74 |138.88 |127.31 |152.77 - | +-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .21 | 77.77 | 93.32 | 84.25 |101.1 | 90.74 |108.88 - | .23 | 85.18 |102.21 | 92.28 |110.73 | 99.38 |119.25 - | .25 | 92.59 |111.10 |100.3 |120.36 |108.02 |129.62 - | .26 | 96.29 |115.54 |104.31 |125.17 |112.44 |134.8 - | .29 |107.41 |128.88 |116.35 |139.62 |125.3 |150.36 - | .3125 |115.55 |138.66 |125.38 |150.45 |135.03 |162.03 - | .33 |122.22 |146.66 |132.4 |158.88 |142.59 |171.10 - | .35 |129.69 |155.54 |140.43 |168.51 |151.23 |181.47 - | .375 |138.88 |166.65 |150.46 |180.55 |162.03 |194.43 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 60 Inches.| .21 | 52.5 | 63. | 58.33 | 69.99 | 64.16 | 76.99 - | .23 | 57.5 | 69. | 63.88 | 76.65 | 70.27 | 84.32 - | .25 | 62.5 | 75. | 69.44 | 83.32 | 76.38 | 91.65 - | .26 | 65. | 78. | 72.22 | 86.66 | 79.44 | 95.32 - | .29 | 72.5 | 87. | 80.55 | 96.66 | 88.61 |106.33 - | .3125 | 78.12 | 93.74 | 86.8 |104.16 | 95.48 |114.57 - | .33 | 82.5 | 99. | 91.66 |109.99 |100.83 |120.99 - | .35 | 87.5 |105. | 97.22 |116.66 |106.94 |128.32 - | .375 | 93.75 |112.5 |104.16 |124.99 |114.58 |137.49 - | +-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .21 | 69.99 | 84. | 75.83 | 90.99 | 81.66 | 97.99 - | .23 | 76.66 | 91.99 | 83.05 | 99.66 | 89.44 |107.32 - | .25 | 83.83 | 99.99 | 90.27 |108.32 | 97.22 |116.66 - | .26 | 86.66 |103.99 | 93.88 |112.65 |101.11 |121.33 - | .29 | 96.66 |115.99 |104.72 |125.66 |112.77 |135.32 - | .3125 |104.18 |124.99 |112.95 |135.54 |121.52 |145.82 - | .33 |109.99 |132. |119.16 |142.99 |128.33 |153.99 - | .35 |116.66 |139.99 |126.38 |151.65 |136.11 |163.33 - | .375 |125. |150. |135.41 |162.49 |145.88 |174.99 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 66 Inches.| .1875 | 42.61 | 51.13 | 47.34 | 56.8 | 52.07 | 62.49 - | .21 | 42.72 | 57.26 | 53. | 63.63 | 58.33 | 69.99 - | .23 | 52.27 | 62.72 | 58. | 69.69 | 63.88 | 76.65 - | .25 | 56.81 | 68.17 | 63.13 | 75.75 | 69.44 | 83.32 - | .26 | 59.09 | 70.9 | 65.65 | 78.78 | 72.22 | 86.66 - | .29 | 65.90 | 79.08 | 73.23 | 87.87 | 80.55 | 96.66 - | .3125 | 71. | 85.2 | 78.91 | 94.69 | 86.89 |104.16 - | .33 | 75. | 90. | 83.33 | 99.99 | 91.66 |109.99 - | .35 | 79.56 | 95.47 | 88.38 |106.05 | 97.22 |116.66 - | .375 | 85.22 |102.26 | 94.69 |113.62 |104.16 |124.99 - | +-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .1875 | 56.81 | 68.17 | 61.55 | 73.86 | 66.28 | 79.53 - | .21 | 63.63 | 76.35 | 68.93 | 82.71 | 74.24 | 89.08 - | .23 | 69.69 | 83.62 | 75.5 | 90.6 | 81.31 | 97.57 - | .25 | 75.75 | 90.90 | 82.07 | 98.48 | 88.37 |106.04 - | .26 | 78.78 | 94.53 | 85.35 |102.42 | 91.91 |110.29 - | .29 | 87.87 |105.44 | 95.2 |114.24 |102.52 |123.02 - | .3125 | 84.69 |113.62 |102.58 |123.09 |110.47 |132.56 - | .33 | 99.99 |120. |108.33 |129.99 |116.66 |139.99 - | .35 |106. |127.27 |114.89 |137.86 |123.73 |148.47 - | .375 |113.62 |136.34 |123.1 |147.72 |132.57 |159.08 - ----------+---------+-------+-------+-------+-------+-------+------- - | |45,000 Tensile |50,000 Tensile |55,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 7,500 | 1-6, 8,333.3 | 1-6, 9,166.6 - | +-------+-------+-------+-------+-------+------- - 72 Inches.| .1875 | 39.06 | 46.87 | 43.4 | 52.08 | 47.74 | 57.28 - | .21 | 43.75 | 52.5 | 48.6 | 58.33 | 53.47 | 64.16 - | .23 | 47.91 | 57.49 | 53.24 | 63.88 | 58.56 | 70.27 - | .25 | 52.08 | 62.49 | 57.87 | 69.44 | 63.65 | 76.38 - | .26 | 54.16 | 64.99 | 60.18 | 72.22 | 66.2 | 79.44 - | .29 | 60.41 | 72.49 | 67.12 | 80.55 | 73.84 | 88.60 - | .3125 | 65.10 | 78.12 | 72.33 | 86.8 | 79.57 | 95.48 - | .33 | 68.75 | 82.5 | 76.38 | 91.62 | 84.02 |100.82 - | .35 | 72.91 | 87.49 | 81.01 | 97.21 | 89.11 |106.93 - | .375 | 78.12 | 93.74 | 86.8 |104.16 | 95.48 |114.57 - | +-------+-------+-------+-------+-------+------- - | |60,000 Tensile |65,000 Tensile |70,000 Tensile - | | Strength. | Strength. | Strength. - | | 1-6, 10,000 | 1-6, 10,833.3 | 1-6, 11,666.6 - | +-------+-------+-------+-------+-------+------- - | .1875 | 52.08 | 62.49 | 56.42 | 67.70 | 60.76 | 72.91 - | .21 | 53.33 | 69.99 | 63.19 | 75.82 | 68.06 | 81.66 - | .23 | 53.88 | 76.65 | 66.21 | 83.05 | 74.58 | 89.43 - | .25 | 69.44 | 83.32 | 75.22 | 90.26 | 81.01 | 97.21 - | .26 | 72.22 | 86.66 | 78.24 | 93.88 | 84.25 |101.10 - | .29 | 80.55 | 96.66 | 87.26 |104.71 | 93.98 |112.77 - | .3125 | 86.8 |104.16 | 94.03 |112.88 |101.27 |121.52 - | .33 | 91.66 |109.99 | 99.3 |119.16 |106.94 |128.32 - | .35 | 97.22 |116.66 |105.32 |126.38 |113.42 |136.1 - | .375 |104.16 |124.99 |112.84 |135.43 |121.52 |145.32 - ----------+---------+-------+-------+-------+-------+-------+------- - - - - -DEFINITION OF TERMS. - - -In the accompanying sections, some of the properties of iron and -steel, as employed in the construction of boilers, are given. It is, -therefore, desirable that the meanings applied to the various terms -used should be clearly understood. The definitions necessary are, then, -briefly as follows:— - - -=Tensile strength= is equivalent to the amount of force which, steadily -and slowly applied in a line with the axis of the test piece, just -overcomes the cohesion of the particles, and pulls it into separate -parts. - - -=Contraction of area= is the amount by which the area, at the point -where the specimen has broken, is reduced below what it was before any -strain or pulling force was applied. - - -=Elongation= is the amount to which the specimen stretches, between two -fixed points, due to a steady and slowly applied force, which pulls and -separates it into parts. Elongation is made up of two parts: one due to -the general stretch, more or less, over the length; the other, due to -contraction of area at about the point of fracture. - - -=Shearing strength= is equivalent to the force which, if steadily and -slowly applied at right angles, or nearly so, to the line of axis of -the rivet, causes it to separate into parts, which slide over each -other, the planes of the surface at the point of separation being at -right angles, or nearly so, to the axis of the rivet. - - -=Elastic limit= is the point where the addition to the permanent set -produced by each equal increment of load or force, steadily and slowly -applied, ceases to be fairly uniform, and is suddenly, after the point -is reached, increased in amount. It is expressed as a percentage of the -tensile strength. - - -=Tough.=—The material is said to be “tough” when it can be bent first -in one direction, then in the other, without fracturing. The greater -the angles it bends through (coupled with the number of times it -bends), the tougher it is. - - -=Ductile.=—The material is “ductile” when it can be extended by a -pulling or tensile force and remain extended after the force is -removed. The greater the permanent extension, the more ductile the -material. - - -=Elasticity= is that quality in a material by which, after being -stretched or compressed by force, it apparently regains its original -dimensions when the force is removed. - - -=Fatigued= is a term applied to the material when it has lost in -some degree its power of resistance to fracture, due to the repeated -application of forces, more particularly when the forces or strains -have varied considerable in amount. - - -=Malleable= is a term applied to the material when it can be extended -by hammering, rolling, or otherwise, without fracturing, and remains -extended. The more it can be extended without being fractured, the more -malleable it is. - - -=Weldable= is a term applied to the material if it can be united, when -hot, by hammering or pressing together the heated parts. The nearer the -properties of the material, after being welded, are to what they were -before being heated and welded, the more weldable it is. - - -=Cold-short= is a name given to the material when it cannot be worked -under the hammer or by rolling, or be bent when cold without cracking -at the edges. Such a material may be worked or bent when at a great -heat, but not at any temperature which is lower than about that -assigned to dull red. - - -=Hot-short= is when the material cannot be easily worked under the -hammer, or by rolling at a red-heat at any temperature which is higher -than about that assigned to a red-heat, without fracturing or cracking. -Such a material may be worked or bent at a less heat. - - -=Homogeneous= describes a material which is all of the same structure -and nature. - -A homogeneous material is the best for boilers, and it should be of -suitable tensile strength with contraction of area and elongation -best suited for the purpose, having an elastic limit that will insure -the structure being reliable; it should be tough and ductile, and its -elasticity fairly good, and be capable of enduring strains without -becoming too quickly or easily fatigued. The material should be -malleable and in some cases weldable; that which is of a decidedly -cold-short or hot-short nature should be avoided. - - - - -BOILER REPAIRS. - - -[Illustration: Fig. 66.] - -This cut represents a form of clamp used in holding the plates against -each other when being riveted. - -[Illustration: Fig. 67.] - - Fig. 67 represents a peculiar form of bolt for screwing a patch to - a boiler. It is threaded into the boiler plate, the chamfer rests - against the patch and the square is for the application of the - wrench. After the bolt is well in place, the head can be cut off with - a cold chisel. - - -REPAIRING CRACKS. - -Cracks in the crown-sheet or side of a fire-box boiler, or top head -of the upright boiler can be temporarily repaired by a row of holes -drilled and tapped touching one another, with 3/8 or 1/2 inch copper -plugs or bolts, screwed into the plates and afterwards all hammered -together. - -For a permanent job, cut out the defect and rivet on a patch. This had -better be put on the inside, so as to avoid a “pocket” for holding the -dirt. In putting on all patches, the defective part must be entirely -removed to the solid iron, especially when exposed to the fire. - -NOTE.—When fire comes to two surfaces of any considerable extent, the -plate next to the fire becomes red-hot and weakens, hence the inside -plate, in repairs, must be removed. - -The application of steel patches to iron boilers is injudicious. Steel -and iron differ structurally and in every other particular, and their -expansion and contraction under the influence of changing temperatures, -is such that trouble is sure to result from their combination. - - -DEFECTS AND NECESSARY REPAIRS. - -[Illustration: Fig. 68.] - -Fig. 68 represents a patch called a “spectacle piece.” This is used -to repair a crack situated between the tube ends. These are usually -caused (if the metal is not of bad quality) by allowing incrustation to -collect on the plate inside the boiler, or by opening the furnace and -smoke doors, thus allowing a current of cold air to contract the metal -of the plates round the heated and expanded tubes. - -The “spectacle piece” is bored out to encircle the tubes adjacent -to the crack, or in other words, to be a duplicate of a portion of -the tube plate cracked. These plates are then pinned on to the tube -covering the crack. - -Steam generators, as they are exposed to more or less of trying service -in steam production, develop almost an unending number and variety of -defects. - -When a boiler is new and first set up it is supposed to be clean, -inside and out, but even one day’s service changes its condition; -sediment has collected within and soot and ashes without. - -Unlike animals and plants they have no recuperative powers of their -own—whenever they become weakened at any point the natural course of -the defect is to become continually worse. - -In nothing can an engineer better show his true fitness than in the -treatment of the beginnings of defects as they show themselves by -well-known signs of distress, such as leaks of water about the tube -ends, and in the boiler below the water line, or escaping steam above -it. In more serious cases, the professional services of a skillful and -honest boiler maker is the best for the occasion. - -In a recent report given in by the Inspectors the following list of -defects in boilers coming under their observation was reported. The -items indicate the nature of the natural decay to which steam boilers -in active use are exposed. The added column under the heading of -“dangerous” carries its own lesson, urging the importance of vigilance -and skill on the part of the engineer in charge. - - Nature of Defects. Whole Number. Dangerous. - Cases of deposit of sediment 419 36 - Cases of incrustation and scale 596 44 - Cases of internal grooving 25 16 - Cases of internal corrosion 139 21 - Cases of external corrosion 347 114 - Broken and loose braces and stays 83 50 - Settings defective 129 14 - Furnaces out of shape 171 14 - Fractured plates 181 84 - Burned plates 93 31 - Blistered plates 232 22 - Cases of defective riveting 306 34 - Defective heads 36 20 - Serious leakage around tube ends 549 57 - Serious leakage at seams 214 53 - Defective water gauges 128 14 - Defective blow-offs 45 9 - Cases of deficiency of water 9 4 - Safety-valves overloaded 22 7 - Safety-valves defective in construction 41 16 - Pressure-gauges defective 211 29 - Boiler without pressure-gauges 3 0 - -This list covers nearly, if not all, _the points of danger_ against -which the vigilance of both engineer and fireman should be continually -on guard; and is worth constant study until thoroughly memorized. - -NOTE. - -Probably one-quarter, if not one-third, of all boiler-work is done -in the way of repairs, hence the advice of men who have had long -experience in the trade is the one safe thing to follow for the -avoidance of danger and greater losses, and for the best results the -united opinion of 1, the engineer, experienced in his own boiler and -2, the boiler-maker with his wider observation and 3, the owner of the -steam plant, all of whom are most interested. - -Corrosion is a trouble from which few if any boilers escape. The -principal causes of external corrosion arise from undue exposure to -the weather, improper setting, or possibly damp brick work, leakage -consequent upon faulty construction, or negligence on the part of those -having them in charge. - -Internal corrosion maybe divided into ordinary corroding, or rusting -and pitting. Ordinary corrosion is sometimes uniform through a large -portion of the boiler, but is often found in isolated patches which -have been difficult to account for. Pitting is still more capricious in -the location of its attack; it may be described as a series of holes -often running into each other in lines and patches, eaten into the -surface of the iron to a depth sometimes of one-quarter of an inch. -Pitting is the more dangerous form of corrosion, and the dangers are -increased when its existence is hidden beneath a coating of scale. -There is another form of decay in boilers known as grooving; it may -be described as surface cracking of iron, caused by its expansion and -contraction, under the influence of differing temperatures. It is -attributable generally to the too great rigidity of the parts of the -boiler affected, and it may be looked upon as resulting from faulty -construction. - -[Illustration: Fig. 69.] - -In plugging a leaky tube with a pine plug, make a small hole, of 3/16 -of an inch diameter, or less, running through it from end to end. These -plugs should never have a taper of more than 1/8 of an inch to the -foot. It is well to have a few plugs always on hand. Fig. 69 exhibits -the best shape for the wooden plug. - - -QUESTIONS - -BY THE PROPRIETOR TO THE ENGINEER IN CHARGE, RELATING TO CONDITION OF -THE BOILER, - - How long since you were inside your boiler? - - Were any of the braces slack? - - Were any of the pins out of the braces? - - Did all the braces ring alike? - - Did not some of them sound like a fiddle-string? - - Did you notice any scale on flues or crown sheet? - - If you did, when do you intend to remove it? - - Have you noticed any evidence of bulging in the fire-box plates? - - Do you know of any leaky socket bolts? - - Are any of the flange joints leaking? - - Will your safety-valve blow off itself, or does it stick a little - sometimes? - - Are there any globe valves between the safety-valve and the boiler? - They should be taken out at once, if there are. - - Are there any defective plates anywhere about your boiler? - - Is the boiler so set that you can inspect every part of it when - necessary? - - If not, how can you tell in what condition the plates are? - - Are not some of the lower courses of tubes or flues in your boiler - choked with soot or ashes? - - Do you absolutely know, of your own knowledge, that your boiler is in - safe and economical working order, or do you merely suppose it is? - - -QUESTIONS - -ASKED OF A CANDIDATE FOR A MARINE LICENSE RELATING TO DEFECTS IN BOILER -WITH ANSWERS. - - If you find a thin plate, what would you do? - Put a patch on. - - Would you put it on inside or outside? - Inside. - - Why so? - Because the action that has weakened the plate will then act on - the patch, and when this is worn it can be replaced; but the plate - remains as we found it. - - If the patch were put on the outside, the action would still be on - the plate, which would in time be worn through, then the pressure of - the steam would force the water between the plate and the patch, and - so corrode it; and during a jerk or extra pressure, the patch might - be blown off. - - It is on the same principle that mud-hole doors are on the inside. - - If you found several thin places, what would you do? - Patch each, and reduce the pressure. - - If you found a blistered plate? - Put a patch on the fire side. - - If you found a plate at the bottom buckled? - Put a stay through the centre of the buckle. - - If you found several? - Stay each, and reduce the pressure. - - The crown of the furnace down? - Put a stay through the middle, and a dog across the top. - - If a length of the crown were down, put a series of stays and dogs. - - A cracked plate? - Drill a hole at each end of the crack; caulk the crack, or put a - patch over it. - - If the water in the boiler is suffered to get too low, what may be - the consequence? - Burn the top of the combustion chamber and the tubes; perhaps - cause an explosion. - - If suffered to get too high? - Cause priming; perhaps cause the breaking of the cylinder covers. - - - - -THE INSPECTION OF STEAM BOILERS. - - -Let it be clearly understood that if there were no steam generators -using steam under pressure _there would he no boiler inspection, and no -licensing of engineers_; it requires no license to be a machinist or -a machine tender, no more would a license be essential to run a steam -engine, except it were connected with the boiler. _The danger to the -public arising from their use requires that the care and management of -high-pressure steam boilers shall be in hands of careful, experienced -and naturally ingenious men_, hence it is on the affairs of the Boiler -Room that the first tests are made, as to the worthiness of an aspirant -for an engineer’s license, hence, too, the success of many firemen in -obtaining the preference over engine-builders or school graduates, in -the line of promotion as steam engineers. - -The inspection laws of the various states and cities are framed after -substantially the same leading ideas, and in presenting one the others -may be assumed to be nearly the same. - -The special province of the Steam Boiler Inspection and Engineers’ -Bureau in the police department in New York City is to inspect and test -all the steam boilers in the city, at certain stated periods, and to -examine every applicant for the position of engineer as to his ability -and qualifications for running an engine and boiler with safety. - -According to the laws of the State, every owner, agent or lessee, of a -steam boiler or boilers, in the city of New York, shall annually report -to the board of police, the location of said boiler or boilers, and, -thereupon, the officers in command of the sanitary company shall detail -a practical engineer, who shall proceed to inspect such steam boiler or -boilers, and all apparatus and appliances connected therewith. - -When a notice is received from any owner or agent that he has one or -more boilers for inspection, a printed blank is returned to him stating -that on the day named therein the boilers will be tested, and he is -asked to make full preparation for the inspection by complying with the -following rules: - - Be ready to test at the above-named time. - Have boiler filled with water to safety-valve. - Have 1-1/4-inch connection. - Have steam gauge. - Steam allowed two-thirds amount of hydrostatic pressure. - -More particularly stated, the following have been adopted by one or -more Inspection Companies: - - -HOW TO PREPARE FOR STEAM-BOILER INSPECTION. - -1. Haul fires and all ashes from furnaces and ash pits. - -2. If time will permit, allow boiler and settings to cool gradually -until there is no steam pressure, then allow water to run out of -boilers. It is best that steam pressure should not exceed ten pounds if -used to blow water out. - -3. Inside of boiler should be washed and dried through manholes and -handholes by hose service and wiping. - -4. Keep safety-valves and gauge-cocks open. - -5. Take off manhole and handhole plates as soon as possible after -steam is out of boiler, that boiler may cool inside sufficiently for -examination; also _keep all doors shut_ about boilers and settings, -_except the furnace and ash-pit doors_. Keep _dampers_ open in _pipes_ -and _chimneys_. - -6. Have all ashes removed from under boilers, and fire surfaces of -shell and heads swept clean. - -7. Have spare packing ready for use on manhole and handhole plates, if -the old packing is made useless in taking off or is burned. The boiler -attendant is to take off and replace these plates. - -8. Keep all windows and doors to boiler room open, after fires are -hauled, so that boilers and settings may cool as quickly as possible. - -9. Particular attention is called to Rule 5, respecting doors—which -should be open and which closed—also arrangement of damper. The -importance of cooling the inside of the boiler by removal of manhole -and handhole plates at the same time the outside is cooling, is in -equalizing the process of contraction. - - -ISSUING CERTIFICATES. - -These conditions having been complied with, the boiler is thoroughly -tested, and if it is deemed capable of doing the work required of -it, a number by which it shall hereafter be known and designated is -placed upon it in accordance with the city ordinance: Failure to comply -with this provision is punishable by a fine of $25. A certificate of -inspection is then given to the owner, for which a fee of $2 is paid. - -This certificate sets forth that on the day named the boiler therein -described was subject to a hydrostatic pressure of a certain number -of pounds to the square inch. The certificate tells where the boiler -was built, its style or character and “now appears to be in good -condition and safe to sustain a working pressure of —— to the square -inch. The safety-valve has been set to said pressure.” A duplicate of -this certificate is posted in full view in the boiler-room. In case -the boiler does not stand the test to which it is subject, it must be -immediately repaired and put in good working order before a certificate -will be issued. - - -THE HYDRAULIC TEST. - -The hydraulic test is a very convenient method of testing _the -tightness of the work in a new boiler_, in conjunction with inspection -to a greater or lesser degree, in the passing of new work. As a -detector of leakages it has no rival, and its application enables -faulty caulking to be made good before the boiler has left the works, -and before a leak has time to enter on its insidious career of -corrosion. The extent to which it enables the soundness and quality of -the work to be ascertained is another matter, and depends on several -conditions. It will be evident that if the test be applied with this -object to a new boiler, the pressure should range to some point in -excess of the working load if such a test is to be of any practical -value. - -What the excess should be so as to remain within safe limits cannot be -stated without regard being paid to the factor of safety adopted in the -structure. - -In addition to the advantage which the hydraulic test affords as a -means of proving the tightness of the riveted seams and work generally, -it is also of frequent assistance in determining the sufficiency of -the staying of flat surfaces, especially when of indeterminate shape, -or when the stresses thrown upon them by the peculiar construction of -the boiler are of uncertain magnitude. For the hydraulic test, however, -to be of any real value in the special cases to which we refer, it is -essential that it should be conducted by an expert, and the application -of the pressure accompanied by careful gaugings, so as to enable the -amount of bulging and permanent set to be ascertained. Without such -readings the application of the test in such cases is worthless, and -may be delusive. Indeed, the careful gauging of a boiler as a record -of its behavior should be a condition of every test, and is a duty -requiring for its adequate performance a skilled inspector. - -The duty of inspecting a new boiler or witnessing the hydraulic test -properly belongs to one of the regular inspecting companies, who have -men in their employ specially trained for the performance of such work. -The advantage accruing from such a course is well worth the fee charged -for the service, and secures a searching inspection of the workmanship, -which frequently brings to light defects and oversights that a mere -pumping-up of the boiler would never reveal. Such a proceeding in fact, -can only prove that the boiler is water-tight, and a boiler may be -tight under test although the workmanship is of the poorest character. -Besides, it is well to bear in mind that the tightness of a boiler -under test is no guarantee of its tightness after it is got to work. -In a word, as far as new boilers are concerned, the application of -hydraulic pressure unaccompanied by careful inspection and gaugings may -be almost worthless, while with these additions it may be extremely -valuable, especially in the case of boilers of peculiar shape, and is a -precaution that should not be neglected. - - - - -ENGINEERS’ EXAMINATIONS. - - -Keeping in mind the fact that _if there were no steam-boilers there -would be no examinations_ and no public necessity for licenses, these -“points” are added. - -Examinations are trying periods with all engineers, as the best are -liable to fail in their answers from a nervous dread of the ordeal, but -the granting of the document is very largely influenced by the personal -experience of the candidate in the practical duties of the engine and -boiler-room, which must be stated and certified to by the evidence of -others. - -_A general knowledge of the subject of steam engineering is the first -requisite to success._ A few sample questions are here given to show -the ordinary course pursued by examiners to determine the fitness of -applicants: - - How long have you been employed as an engineer, and where? Are you - a mechanic? Where did you learn your trade? Give some idea of the - extent of your experience as an engineer? What kind of boilers have - you had charge of? Describe a horizontal tubular boiler. Describe a - locomotive style boiler. Describe a vertical style boiler. Describe - a sectional water tube boiler. How thick is the iron in the shell - of your boiler? How thick should it be in the shell of your boiler? - How thick are the heads in your boiler? How thick should they be in - your boiler? How are the heads fastened to the shell? What is the - best way to put heads in a boiler? How is the shell riveted? What - size rivets are used? What distance apart are they? How should the - shell be riveted? Why do they double rivet some seams? What ones - are best double riveted? How is a horizontal boiler braced? How is - a locomotive boiler braced? What is the size of and forms of braces - generally used? What is the size of your boiler or boilers, length - and diameter? How many have you in charge? Name the horse power. How - many tubes are in the boiler? What size are they, and how thick? How - long are they? How are they secured? What is the difference between a - socket and a stay bolt? What is the tensile strength of Boiler Iron? - What is the tensile strength of Boiler Steel? What is mild steel? - What is CH No. 1 Iron? What is Flange Iron? What is Hot Short and - Cold Short Iron? What is the common dimensions of a Man Hole? What is - it for? What are Hand Holes for? Do you open them often? How often? - What are Crown Bars and where are they used? How is a Boiler Caulked? - What is a Drift Pin? - - - - -MECHANICAL STOKERS. - - -In the back counties of England for many generations before the steam -engine was evolved from the brains of Trevithick, Watt and Stephenson, -the word “stoke” was used, meaning to “stir the fire.” The word was -derived from an ancient word, stoke, meaning a stick, stock or post. - -To-day there are very many men who are called “stokers,” employed -principally on locomotive engines, steam vessels, etc., and then there -is the “stoke hole,” so-called, in which they do their work. - -[Illustration: Mechanical Stoker] - -But, now comes the “mechanical stoker,” which is well named, as its -office is to feed and “stir the fire” by a machine, thus relieving -the fireman from much excessively hard toil and allowing the time and -energy thus saved to be more profitably used elsewhere. The figure -shows a view of the American Stoker which is a device of the most -advanced type. - -The principal parts of the machine are: 1, the Hopper, which may -be filled either by hand shoveling or by elevating and conveying -machinery; 2, the Conveyor Screw, which forces the coal, or indeed, any -description of fuel, forward to the 3, Magazine, shown in the figure -to the left; 4, a Driving Mechanism, which is a steam motor arranged -conveniently in front of the hopper; 5, the Retort, so called from its -being the place (above the conveyor) where the coal is distilled into -gas. - -NOTE.—An illustrated printed description of this machine is issued and -sent free upon application by the makers. The American Stoker Co., -Washington Life Building, Cor. Broadway and Liberty St., New York. - -The rate of feeding coal is controlled by the speed of the motor, this -being effected by the simple means of throttling the steam in the -supply pipe to the motor. The shields covering the motor effectually -protect the mechanism from dirt and dust. The motor has a simple -reciprocating piston; its piston rod carries a crosshead, which, by -means of suitable connecting links, operates a rocker arm having a pawl -mechanism, which in turn actuates the ratchet wheel attached to the -conveyor shaft. The stoker is thus entirely self-contained and complete -in itself. - -A screw conveyor or worm is located in the conveyor pipe and extends -the entire length of the magazine. Immediately beneath the conveyor -pipe is located the wind-box, having an opening beneath the hopper. - -At this point is connected the piping for the air supply, furnished at -low pressure by a volume blower. The other end of the wind-box opens -into the air space between the magazine and outer casing. The upper -edge of the magazine is surrounded by tuyeres, or air blocks, these -being provided with openings for the discharge of air, inwardly and -outwardly. - -The stoker rests on the front and rear bearing bars; the space between -the sides of the stoker and side walls is filled with iron plates, -termed “dead grates.” Steam is carried to the motor by a 3/4-inch steam -pipe. The exhaust steam from the motor is discharged into the ash pit. - -In operation the coal is fed into the hopper, carried by the conveyor -into the magazine, which it fills, “overflows” on both sides, and -spreads upon the sides of the grates. The coal is fed slowly and -continuously, and, approaching the fire in its upward course, it is -slowly roasted and coked, and the gases released from it are taken up -by the fresh air entering through the tuyeres, which explodes these -gases and delivers the coal as coke on the grates above. The continuous -feeding gives a breathing motion to this coke bed, thus keeping it open -and free for the circulation of air. - -It will be noted that in this machine the fuel is introduced from the -bottom of the bed of fuel, technically speaking, upon the principle of -“underfeeding.” - - - - -CHEMICAL TERMS - -AND EXPLANATIONS RELATING TO FEED WATERS. - - -=_Chemistry_= is a science which investigates _the composition and -properties of material substances_. - -Nature is composed of elementary elements; knowledge of these bodies, -of their mutual combinations, of the forces by which these combinations -are brought about, and the laws in accordance with which these forces -act, constitute chemistry, and the chemistry of steam engineering -largely deals with the foreign bodies contained in the feed water of -steam boilers. - - -=_Element._= In general, the word element is applied to any substance -which has as yet never been decomposed into constituents or transmuted -to any other substance, and which differs in some essential property -from every other known body. The term simple or _undecomposed -substance_ is often used synonymously with element. - -There are about 70 _simple elements_, three-quarters of which are to -be met with only in minute quantities and are called rare elements. -Copper, silver, gold, iron, and sulphur are simple elements—_the metal -irridium, for example, is a rare element_—it is the metal which tips -the ends of gold pens—it is heavier than gold and much more valuable. -Probably there are not two tons of it in existence. - - -=_A Re-agent_= is a chemical used to investigate the qualities of some -other chemical—example, hydrochloric acid is a re-agent in finding -carbonic acid in limestone, or carbonate of lime, which when treated by -it will give up its free carbonic acid gas, which is the same as the -gas in soda water. - - -=_An Oxide_= is any element, such as iron, aluminium, lime, magnesia, -etc., combined with oxygen. To be an oxide _it must pass through the -state of oxidization_. Iron after it is rusted is the oxide of iron, -etc. - - -=_A Carbonate_= is an element, such as iron, sodium, etc., which forms -a union with carbonic acid—the latter is a mixture of carbon and -oxygen in the proportion of 1 part of carbon to 2 of oxygen. Carbonic -acid, as is well known, does not support combustion and is one of the -gases which come from perfect combustion. This acid, or what may be -better termed a gas, is plentifully distributed by nature and is found -principally combined with lime and magnesia, and in this state (_i.e._, -carbonate of lime and carbonate of magnesia) is one of the worst -enemies to a boiler. - - -=_An Acid_= is a liquid which contains both hydrogen and oxygen -combined with some simple element such as chlorine, sulphur, etc. It -will always turn blue litmus red, and has that peculiar taste known as -acidity; acids range in their power from the corrosive oil of vitriol -to the pleasant picric acid which gives its flavor to fruits. - - -=_Alkalies_= are the opposite to an acid; they are principally potash, -soda and ammonia—these combined with carbonic acid form carbonates. -Sal-soda is carbonate of soda. - - -=_A Chloride_= is an element combined with hydro chloric acid—common -salt is a good example of a chloride—being sodium united with the -element chlorine, which is the basis of hydro chloric acid. Chlorides -are not abundant in nature but all waters contain traces of them more -or less and they are not particularly dangerous to a boiler. - - -=_Sulphates_= are formed by the action of sulphuric acid (commercially -known as the oil of vitriol) upon an element, such as sodium, magnesia, -etc. The union of sodium and sulphuric acid is the well-known Glauber -salts—this is nothing more than sulphate of soda; _sulphate of lime is -nothing more than gypsum_. Sulphates are dangerous to boilers, if in -large quantities _should they give up their free acid_—the action of -the latter being to corrode the metal. - - -=_Silica_= is the gritty part of sand—it is also the basis of all -fibrous vegetable matter—a familiar example of this is _the ash_ which -shows in packing, which has been burnt by the heat in steam; by a -peculiar chemical treatment silica has been made into soluble glass—a -liquid. 65 per cent. of the earth’s crust is composed of silica—it -is the principal part of rock—pure white sand is silica itself—it is -composed of an element called _silicum_ combined with the oxygen of the -air. Owing to its abundance in nature and its peculiar solubility it is -found largely in all waters that come from the earth and is present in -all boiler scale. - -In water analysis the term _insoluble matter_, is silica. This is one -of the least dangerous of all the impurities that are in feed water. - - -=_Magnesia_= is a fine, light, white powder, having neither taste nor -smell, almost insoluble in boiling, but less so in cold water. Magnesia -as found in feed water exists in two states, oxide and a carbonate, -when in the latter form and free from the traces of iron, tends to give -the yellow coloring matter to scale—in R. R. work, yellow scale is -called magnesia scale. - - -=_Carbonate of Magnesia_= is somewhat more soluble in cold than in hot -water, but still requires to dissolve it 9,000 parts of the latter and -2,493 of former. - -Magnesia, in combination with silica, enters largely into the -composition of many rocks and minerals, such as soapstone, asbestos, -etc. - - -=_Lime_=, whose chemical name is _calcium_, is a white alkaline earthy -powder obtained from the native carbonates of lime, such as the -different calcerous stones and sea shells, by driving off the carbonic -acid in the process of calcination or burning. - -Lime is procured on a large scale by burning the stone in furnaces -called kilns, either mixed with the fuel or exposed to the heated air -and flames that proceed from side fires through the central cavity of -the furnace in which the stones are collected. - -The calcined stones may retain their original form or crumble in part -to powder; if protected from air and moisture they can afterwards be -preserved without change. - - -=_Soda_= is a grayish white solid, fusing at a red heat, volatile with -difficulty, and having an intense affinity for water, with which it -combines with great evolution of heat. - -The only reagent which is available for distinguishing its salts from -those of the other alkalies is a solution of antimoniate of potash, -which gives a white precipitate even in diluted solutions. - -=_Sodium_= _is the metallic base of soda._ It is silver white with -a high lustre; crystallizes in cubes; of the consistence of wax at -ordinary temperatures, and completely liquid at 194°, and volatilizes -at a bright red heat. It is very generally diffused throughout nature -though apparently somewhat less abundantly than potassium in the solid -crust of the globe. - -=_Salt_=, the chloride of sodium, a natural compound of one atom of -chloride and one of sodium. It occurs as a rock inter-stratified with -marl, and sandstones, and gypsum, and as an element of salt springs, -sea water, and salt water lakes. - -The proportions of its elements are 60.4 per cent. of chlorine and 39.6 -per cent. of sodium. - -In salt made of sea water the salts of magnesia with a little sulphate -of lime are the principal impurities. - -The above mentioned chemical substances can be classified into two -distinct classes, _i.e._, incrusting and non-incrusting. - -Of the incrusting salts, carbonate of magnesia is the most -objectionable, and any feed water that contains a dozen grains per -gallon of magnesia can be expected to have a most injurious effect on -the boiler, causing corrosion and pitting. Carbonate of lime, while not -as bad as the magnesia carbonate, yet has a very destructive action on -a boiler and 20 grains per gallon of this is considered bad water. All -silicates, oxides of iron, and aluminium, and sulphate of lime are also -incrusting. The non-incrusting substances are three, viz., chloride of -sodium (common salt), and sulphate and carbonate of soda. - -NOTE. - -In view of the increasing importance laid upon a knowledge of the -chemical formation of feed water, these chapters of Chemical Terms and -Analysis of Feed Waters are given to indicate _the direction in which -the advanced engineer must push his inquiries_. There are more millions -of treasure to be made by properly “treating” the water which enters -the steam generators of the world than can be extracted from its gold -mines. - -An important “point” is to make sure, before adopting any permanent -system for purifying the waters of a steam plant, that it is always the -same in its ingredients, _i.e._, that the impurities contained in the -water are the same at all times. - - - - -ANALYSIS OF FEED WATER. - - -In response to a generous offer made by a leading engineering journal, -the following compositions of feed water were ascertained and -published. The “Directions” show how the water was forwarded, and the -tables, the result of careful examination, of samples sent from widely -separated sections of the country. - - -DIRECTIONS. - -1. Get a clean gallon jug or bottle and a new cork (or, at all events, -a thoroughly clean one). - -2. Wash out the vessel two or three times with the same water that is -going to be sent in it. This is to make sure that the sample may not be -contaminated with any “foreign” ingredient. - -3. Tie the cork, after the bottle is filled with the water, with a -strong string or wire. Pack the bottle so secure, with hay or straw, -sawdust, or newspapers, that it may not knock itself to pieces against -the sides of the box. - - - FROM ARGOS, IND. - Grains per - Gallon. - - Silica 1.1096 - Oxides of iron and aluminium .1752 - Carbonate of lime 11.9010 - Carbonate of magnesia 5.4597 - Carbonate of soda 1.1324 - Chloride of sodium .0715 - ------- - Total solids 19.8494 - - - FROM SIOUX FALLS, S. D. - Grains per - Gallon. - Silica .8292 - Oxides of iron and aluminium .2452 - Carbonate of lime 9.0699 - Carbonate of magnesia 5.4376 - Chloride of sodium 1.7172 - Sulphate of sodium 4.5245 - Sulphate of lime 2.6976 - ------- - Total solids 25.0936 - - - FROM LITCHFIELD, ILL. Grains per - Gallon. - Silica .4711 - Oxides of iron and aluminium .7475 - Carbonate of lime .3800 - Carbonate of magnesia 2.2911 - Chloride of sodium 8.7543 - Sulphate of soda 16.0329 - Sulphate of lime 2.8168 - ------- - Total solids 31.4835 - - - FROM CHELSEA, MASS. Grains per - Gallon. - Silica .1168 - Oxides of iron and aluminium .6540 - Carbonate of lime 34.5260 - Carbonate of magnesia 22.8470 - Chloride of sodium 63.2041 - Sulphate of soda 28.4711 - Carbonate of soda 32.2321 - -------- - Total solids 182.0511 - - - FROM MEMPHIS, TENN. Grains per - Gallon. - Silica .8292 - Oxides of iron and aluminium .4789 - Carbonate of lime 1.8337 - Carbonate of magnesia .9956 - Carbonate of soda 1.9792 - ------ - Total solids 6.1166 - - - FROM PEKIN, ILL. Grains per - Gallon. - Silica 1.0628 - Oxides of iron and aluminium Trace - Carbonate of lime 10.0915 - Carbonate of magnesia 5.8224 - Chloride of soda Trace - Sulphate of soda 1.2456 - ------- - Total solids 18.6471 - - - FROM TIFFIN, OHIO. Grains per - Gallon. - Silica .5256 - Oxides of iron and aluminium .2336 - Carbonate of lime 12.6144 - Carbonate of magnesia 10.2652 - Carbonate of soda 2.4137 - Sulphate of soda 6.8296 - Chloride of sodium 1.0484 - ------- - Total solids 33.9395 - - - - -CORROSION AND INCRUSTATION OF STEAM BOILERS. - - -No more perplexing question presents itself to the engineer and steam -user than the one to be inferred from the above heading. Enormous -losses of money, danger to life and property and the loss of position -and the reputation of the engineer are involved in it. How to avoid -these actual evils is of the first importance in steam economy. The -subject at first sight seems to the average student a difficult -one to master, but like all other matters pertaining to mechanics, -investigation that is backed with reason, will show that much that -appears obscure is really very plain indeed; this is because nature, -even down to the sediment remaining in a boiler after the conversion of -water into steam, operates in its formation with infinite exactness and -along well known lines. - - Question.—What is corrosion? - Answer.—_Corrosion is simply rusting_ or the wasting away of the - surfaces of metals, for particulars of which see page 126. - - Question.—What is incrustation? - Answer.—_Incrustation means_ simply _a coating over_. - Water, on becoming steam, is separated from the impurities which it - may have contained, and these form sediment and incrustation. - -Boilers corrode _on the outside as well as within_, and to a great -extent unless carefully cleaned and painted; but it is the damage -caused by “hard” and acidulated water within the boiler that is to be -principally guarded against. - -An extreme example of incrustation has been described in that of -a locomotive type of a stationary boiler. Its dimensions were: -seventy-two inches in diameter, twenty-two feet long, with 153 -three-inch tubes; shell, three-eighths; head, three-eighths, and made -of iron. The scale against the back head was nearly two inches thick -and completely filled the space between the tubes, so that circulation -was impossible, the only wonder being that the boiler did not give out -sooner than it finally did. The scale was even with the top row of -tubes, the only part of the boiler generating steam being the fire box -and the upper row of tubes, the others acting simply as smoke conduits. -There was certainly a great loss of fuel, quite fifty per cent. Had -it been a horizontal boiler it would have burned out before the scale -became so heavy. - -In the above instance, the loss in fuel is estimated at one-half. -Careful experiment has proved an average loss of fuel as follows: - - 1/16 inch of scale causes a loss of 13 per cent. of fuel. - 1/4 inch of scale causes a loss of 38 per cent. of fuel. - 1/2 inch of scale causes a loss of 60 per cent. of fuel. - -It must be remembered that dry steam, as it is used through the engine -or for other purposes, _carries away none of the impurities_ which pass -with the water into the boiler; hence, in a battery of boilers burning, -say, 20 tons of coal per day and evaporating 10 lbs. of water to a -pound of coal, there is a body of water going through them every day of -200 tons. Multiply this by 300 days for a year = 60,000 tons, and it -will be seen how very great is the problem of keeping the interior of -the boilers free from scale and deposit. - -Chemically pure water is that which has no impurities, and may be -described as colorless, tasteless, without smell, transparent, and in a -very slight degree compressible, and, were a quantity evaporated from a -perfectly clean vessel, there would be no solid matter remaining. - -But, strangely, investigation has proved that water of this purity -rapidly corrodes iron, and attacks even pure iron and steel more -readily than “hard” water does, and sometimes gives a great deal of -trouble where the metal is not homogeneous. Marine boilers would be -rapidly ruined by pure distilled water if not previously “scaled” about -1/32 of an inch. - -Water is formed by the union of two gases—oxygen and hydrogen. These -two are _simple bodies_, formed by the Creator in the beginning, which -are found _in combination_ in thousands of different forms. Both when -alone are invisible. Take one volume of oxygen and mix it with two -volumes of hydrogen and they will chemically unite and form water. This -is by measure. _By weight_ water is composed of 88.9 of oxygen to 11.1 -of hydrogen = 100 parts. See pages 229, 230 for further information. - -It is an important point to remember that when water is expanded about -1,700 times into steam, it is simply expanded water, as ice is hardened -water, _i.e._, in expanding into steam the two constituent gases do not -separate. Hence, in dealing with the impurities inside the boiler, -it is to be observed that in no sense do they change the essential -nature of water itself. The impurities are simply _foreign bodies_, -which have no legitimate place in the boiler, and are to be expelled -as dangerous foes. As a general principle, it may be stated that it is -more profitable to soften and filter the water used in boilers than to -trust to blowing out or dissolving the sediment and scale that will -be otherwise formed, for observations show that “anti-incrustators” -containing organic matter help rather than hinder incrustations, and -are therefore to be avoided. For the remedy of foul water there are -numerous contrivances to prevent it from entering the boiler, which -is far better than trying to extract the sediment after it is there, -though there are many ingenious methods for doing that also, some of -which will be detailed hereafter. - - -PRELIMINARY PRECIPITATION OF WATER. - -A good method of avoiding incrustations in steam boilers is evidently -a preliminary purification of the feed-water, provided it can be done -by means sufficiently simple. This is a problem which it is claimed has -been solved by M. Dehne of Halle, by means of an arrangement which we -will herewith describe. The fresh water, which is taken up by a feed -pump, is sent into a heater where it is raised to a temperature that -will be favorable to chemical reaction. It then passes into a mixer -where it encounters certain reacting agents which have been pumped in -there by a pump of special design. These reacting agents are composed -of a mixture of carbonate of soda and of caustic soda, the carbonate -of soda serving to precipitate the sulphate of lime contained in the -feed water, while the caustic soda precipitates the carbonate of lime -and the magnesia. The relative dimensions between the special pump -and the feed pump are calculated in such a way that the proportions -of carbonate of soda and caustic soda in the mixture have always a -certain relation to the amount of lime and magnesia to be precipitated. -The water of the mixture is frequently very much disturbed by the -precipitations which are formed, and passes into a filter where all the -matters that are held in suspension are retained. It then goes into the -boiler. In cases where the feed-water is taken from a tank, the heater, -the mixer, and filter are put in the suction pipe of the feed pump, but -if, as often happens, the water is already under pressure and will pass -directly through the three, the feed pump will take the water directly -from the filter and pump it directly into the boiler. - - -A PRECIPITATOR FOR SEA WATER. - -It is quite possible to prepare sea water in such a way as to -practically prevent any serious deposit forming from it. - -The process employed is to add to the sea water a known quantity of -precipitator powder consisting chiefly of soda ash, and having done -this in a closed vessel, to heat the mixture by blowing into it waste -steam, until a pressure of from 5lbs. to 10lbs. is created; under these -circumstances practically all the magnesium and calcium salts separate -from the water and are easily got rid of by filtering it under pressure -into the hot-well. - -A precipitator 6 ft. 4 in. high and 3 ft. in diameter, holds a ton of -water, and the time taken, from the first running the sea water in, to -its delivery into the hot-well, need not exceed 1 hour and 15 minutes, -so that in practice, giving plenty of time between the makes, it would -be perfectly easy to prepare 8 to 12 tons in the 24 hours with a small -precipitator of the size named. The prepared water has a density of -l/32nd, and may with safety be evaporated until its density is 5/32nds, -the salts present not crystalizing out until a density of from 6/32nds -to 7/32nds is reached. - -In preparing sea water in the way proposed, every precaution must -be taken to add slightly less of the precipitant than is necessary -to entirely throw down the calcium and magnesium salts, as it is -manifestly impossible in practice to guard against small quantities of -sea water finding way into the boiler either from leaky condensers or -else being fed in by the engineer during some emergency, and if under -these conditions any excess of the precipitant were present in the -boiler, a bulky precipitate would be thrown down and cause trouble, -although it would not bind into a solid scale. - -Briefly recapitulated the means which are best adapted for preventing -the formation of the dangerous organic and oily deposits considered are: - - I. Filtration of condensed water through a coke column. - - II. Free use of the scum cocks. - - III. The use of water of considerable density rather than of fresh - water. - - IV. The use of pure mineral oil lubricants in the smallest possible - quantity. - - -SCALE DEPOSITED IN MARINE BOILERS. - -The analysis given below may be looked upon as typical of the -incrustation formed by fresh water, brackish water and sea water -respectively in marine boilers: - - Constituent. River. Brackish. Sea. - Calcic carbonate 75.85 43.65 0.97 - „ sulphate 3.68 34.78 85.53 - Magnesic hydrate 2.56 4.34 3.39 - Sodic chloride 0.45 0.56 2.79 - Silica 7.66 7.52 1.10 - Oxides of iron and alumina 2.96 3.44 0.32 - Organic matter 3.64 1.55 trace - Moisture 3.20 4.16 5.90 - ------ ------ ------ - 100.00 100.00 100.00 - -From this it is evident we may look upon the incrustation from fresh -water as consisting of impure calcic carbonate, whilst that from sea -water is impure calcic sulphate, the brackish water from the mouths of -rivers yielding, as might be expected, an incrustation in which both -these compounds are present in nearly equal quantities. - -The importance of these differences in the deposit formed is very -great, as it enables the shipowner to arrive at the conclusion as to -the treatment that the boilers have received during the voyage, by -examination and analysis of the scale that those boilers contain. -Taking, for instance, the case of a ship which uses fresh water -both for filling and make up, it is manifest that on her return to -port the scale should be very slight and should consist mainly of -calcic carbonate, whilst if the scale exceeds 1/16 in., and shows a -preponderance of calcic sulphate, it is manifest that such scale could -only have been formed by sea water, either leaking in from faulty -condensers or being deliberately fed into the boilers. - -With the introduction of high pressure steam a new and dangerous form -of deposit has added to the trouble of the marine engineer; having -entered the boiler, the minute globules of oil, if in great quantity, -coalesce to form an oily scum on the surface of the water, or if -present in smaller quantities, remain as separate drops; but show no -tendency to sink, as they are lighter than water. - -Slowly, however, they come in contact with small particles of other -solids separating from the water and sticking to them, they gradually -coat the particles with a covering of oil, which in time enables -the particles to cling together or to the surfaces which they come -in contact with. These solid particles of calcic carbonate, calcic -sulphate, etc., are heavier than the water, and, as the oil becomes -more and more loaded with them, a point is reached at which they have -the same specific gravity as the water, and then the particles rise -and fall with the convection currents which are going on in the water, -and stick to any surface with which they come in contact, in this way -depositing themselves, not as in common boiler incrustation, where they -are chiefly on the upper surfaces, but quite as much on the under sides -of the tubes as on top. - -The deposit so formed is a wonderful non-conductor of heat, and also -from its oily surface tends to prevent intimate contact between -itself and the water. On the crown of the furnaces this soon leads to -overheating of the plates, and the deposit begins to decompose by heat, -the lower layer in contact with the hot plates giving off various gases -which blow the greasy layer, ordinarily only 1/64 inch in thickness, up -to a spongy leathery mass often 1/3 inch thick, which, because of its -porosity is an even better non-conductor of heat than before, and the -plate becomes heated to redness. - -When water attains a temperature, as it does under increasing pressure, -ranging from 175° to about 420° Fahr., all carbonates, sulphates and -chlorides are deposited in the following order: - - First. Carbonate of lime at 176° and 248° Fahr. - - Second. Sulphate of lime at 248° and 420°. - - Third. Magnesia, or chlorides of magnesium, at 324° and 364°. - -It is to take advantage of this fact that mechanically arranged jets, -sprinklers and long perforated pipes are introduced into the interior -of the boiler; these tend to scatter the depositing impurities and also -to bring the feed water more quickly to the highest heat possible. - -With regard to the oxide of iron or iron salts in solution, these can -best be treated with small quantities of lime. By adding re-agents, -they set up chemical changes, which result in precipitation, which -give the water a milky appearance; they divide into particles, and -ultimately settle, leaving the water pure and bright. The mechanical -treatment on a limited scale would be easy, a settling tank sufficing; -but this becomes a different matter when large quantities have to be -dealt with. - -ANALYSIS OF AVERAGE BOILER SCALE. - - Parts per 100 parts - of deposit. - - Silica .042 parts. - Oxides of iron and aluminium .044 „ - Carbonate of lime 30.780 „ - Carbonate of magnesia 51.733 „ - Sulphate of soda Trace „ - Chloride of sodium Trace „ - Carbonate of soda 9.341 „ - Organic matter 8.060 „ - -------------- - Total solids 100. Parts - -The percentage only of each ingredient the scale is composed of is -given, as it cannot be told how much water was evaporated to leave this -amount of solid matter. - - -A LOCOMOTIVE-BOILER COMPOUND. - -The lines of a certain great R. R. traverse a country where the -water is very hard and they are compelled to resort to some method -of precipitating the lime that is held in solution. After many tests -and experiments they have made a compound and use it as follows: in -a barrel of water of a capacity of fifty gallons they put 21 lbs. of -carbonate of soda, or best white soda ash of commerce, and 35 lbs. of -white caustic soda. The cost, per gallon, is about 2-1/2 cents. - -The compound is carried in this concentrated form, in calomine cans -on the tender of each locomotive. A certain amount, according to the -necessities of the case, is poured into the tender at the water tank -at each filling. This amount is determined by analysis, and varies all -the way from two to fifteen pints to two thousand gallons of water. -The precipitating power of this compound may be taken roughly at 2/3 -of a pound of the carbonate of lime, or equivalent amount of other -material, per pint of the compound. On their western lines where they -are dealing with alkali waters and those containing sulphates, the -company use merely 60 pounds of soda ash to a barrel of water. When the -water is pumped into the boiler the heat completes the precipitation -and aggregation of the particles, and this does away with all trouble -of the tenders or injector tubes clogging up. - -The case is an interesting one to stationary engineers, because where -the water is pumped into the boiler from tanks the same compound -can be used, provided the water contains the proper constituents to -be precipitated by it; and where the water is taken from city water -mains, it would be a simple matter to devise an apparatus to admit the -compound to the feed pipes. - - -“POINTS” RELATING TO THE SCALING OF STEAM BOILERS. - -The peculiarity about the sulphate of lime is that _the colder the -water the more of it will be held in solution_. Water of ordinary -temperature may hold as high as 7 per cent. of lime sulphate in -solution, but when the temperature of the water is raised to the -boiling point a portion of it is precipitated, leaving about .5 of one -per cent. still in solution. Then as the temperature of the water is -raised, still more of the substance is precipitated and this continues -until a gauge pressure of 41 pounds has been reached which gives a -temperature of about 200 degrees; at this point all the sulphate of -lime has been precipitated. Many other scale forming substances act in -a similar manner. This shows quite plainly that any temperature that -can be produced by the use of exhaust steam would not be sufficient to -cause the precipitation of all the substances which might be contained -in the water. - -That boiler incrustations are the immediate causes of the majority of -steam boiler explosions is no longer a doubtable question. - -Nearly all foreign matter held in solution in water, on first becoming -separated by boiling, _rises to the top in the form of what is commonly -called scum_, in which condition much of it may be removed by the -surface blow-off. If not removed, however, the heavier particles will -be attracted to each other until they have become sufficiently dense to -fall to the bottom, where they will be deposited in the form of scale, -covering the whole internal surface of the boiler below the water line, -with a more or less perfect non-conductor of heat. - -It is recorded that the engineer of the French ocean steamer _St. -Laurent_ omitted to remove a bar of zinc when repairing and cleaning -out his boilers. On opening the boilers at the end of the voyage to his -great surprise he found that the zinc had disappeared, but his boilers -were entirely free from scale and the boiler plates not injured in the -least. - -It has been recently determined by some German experimenters that -sugar effects a strong action upon boilers. It has an acid reaction -upon the iron which dissolves it with a disengagement of hydrogen. The -amount of damage done increases with the amount of sugar in the water. -These results are worthy of note in sugar refineries and places where -sugar sometimes finds its way into the boilers by means of the water -supplied. The experimenters in question also find that zinc is strongly -attacked by sugar; copper, tin, lead and aluminium are not attacked. - -Two reasons, relating to incrustations, for not blowing out a boiler -while under steam pressure may be given as follows: One is, that the -foreign matter floating on top of the water will be deposited on the -shell of the boiler as the water gradually subsides, and, second, -the heated walls of the furnace will communicate a sufficiently high -temperature to the boiler to dry and flake the sediment that would -otherwise remain in the boiler in the shape of mud, which could easily -be washed out were it not for the baking process. - -Bark, such as is used by tanners, has an excellent effect on boiler -incrustations. It may be used as follows: Throw into the tank or -reservoir from which the boilers are fed a quantity of bark in the -piece, in sufficient quantity to turn the water to a light brown -color. Repeat this operation every month at least, using only half -the quantity after the first month. Add a very small quantity of the -muriate of ammonia, about one pound for every 2,000 gallons of water -used. This will have the effect of softening as well as disintegrating -_the carbonate of lime_ and other impurities deposited by the action of -evaporation. - -NOTE.—Care must be exercised in keeping the bark, as it becomes broken -up, from the pump valves and blow-off valves. This may be accomplished -by _throwing it into the reservoir confined in a sack_. - -Among the best samples of boiler compounds ever sent to the laboratory -for analysis was found to be composed of: - - Pounds - Sal soda 40 - Catechu 5 - Sal ammoniac 5 - -This solution was formerly sold at a good round figure, but since its -nature became more generally known, it is not found in market, but is -largely used, consumers putting it up in lots sufficient to last a year -or so at a time. - -The above is strongly recommended by those who have used it, _one pound -of the mixture being added to each barrel of water used_ but after the -scale is once thoroughly removed from the boiler, the use of sal soda -alone is all that is necessary. By the use of ten pounds per week a -boiler 26 feet long and 40 inches in diameter in one of the iron mills -of New Albany, Ind., has been kept clean of scale equal to a new boiler. - -There are other evils sometimes inherent in hard waters over and above -the mere production of a crust. Some waters contain a great deal of -soluble magnesia salts, together with common salt. When this is the -case there is a great chance of corrosion, for the former is acted on -by steam at high pressure in such a way that muriatic acid fumes are -produced, which seriously corrodes the boiler, and, what is far worse, -passes with the steam into the engine, and produces corrosion in the -cylinders and other delicate fittings into contact with which the -steam passes. All this can, however, be obviated by the removal of the -magnesia from the water. - -There has not been, and never can be, made a mechanical device which -will precipitate all the ingredients contained in a water taken from -a natural source of supply, and if it were possible to do so it would -be the most ruinous thing one could do for the boilers, as water is -the greatest _solvent_ known to chemistry, and its nature is to hold -in solution and be impregnated with the different elements it comes in -contact with, to a certain per cent., and if its lime, magnesia, and -the mineral salts are taken away, and the pure water is pumped into -the boilers, it will take up the iron, causing pitting and grooving of -the boilers. It is better to let nature take its course, to a certain -extent, and neutralize what little mineral deposit forms in the boilers -with as small an amount of vegetable matter as possible. - -It is well to note that different waters require different treatment; -what will be of benefit in one instance will be of no value whatever in -a different water, many of the “compounds” sold to prevent and remove -scale will certainly destroy a boiler if they are used persistently, -because they are composed of the exact opposite chemicals which should -be used; as an example it is stated that at one establishment one -thousand dollars were expended annually for a mixture which it is said -resulted in the reduction of the life and usefulness of the boilers of -50 per cent. - - - - -ENGINEERS’ TESTS - -FOR IMPURITIES IN FEED WATER. - - -Much expense can be saved in fuel and boiler repairs by a little -preliminary expenditure of money in securing a supply of good water -for the steam boilers of a new establishment. Well water is nearly -always inferior to the running water of streams; water from mines is -especially hurtful, containing, as they do, large quantities of free -sulphuric acid. Wells along the sea shore or on the banks of rivers -affected by the tides, are likely to be saturated with chloride of -magnesium. It is in determining these points that these ready tests of -feed water are most useful. - -A thorough and really scientific analysis of feed water is a costly -and tedious process, but _a simple and perhaps sufficiently accurate -test_ may be made as follows: take a large (or tall) clear glass vessel -and fill it with the water to be tested; add a few drops of water of -ammonia, until the water is distinctly alkaline; next add a little -phosphate of soda; the action of this is to change the lime, magnesia, -etc., into phosphates, in which form they are deposited in the bottom -of the glass. The amount of the matter thus collected gives a crude -idea of the relative quality of sediment and scale-making material in -the water. - -Water turning _blue litmus paper red_, before boiling, contains an -acid, and if the blue color _can be restored by heating_, the water -contains carbonic acid. Litmus paper is sold by druggists. - -If the water has a foul odor, giving a black precipitate with acetate -of lead, it is sulphurous. - -An experiment may be tried by dissolving common white or other pure -soap in a glass of water, and then stirring into the glasses of water -to be tested a few teaspoonsful of the solution; the matter which will -be deposited will show the comparative amount of the scale-making -material contained in the feed water. - -_In order to ascertain the proportion of soda to the feed water the -following method is recommended_: - -1. Add 1/16th part of an ounce of the soda to a gallon of the feed -water _and boil it_. 2. When the sediment thrown down by the boiling -has settled to the bottom of the kettle, pour the clear water off, and -3, add 1/2 drachm of soda. Now, if the water remains clear, the soda, -which was first put in, has removed the lime, but if it becomes muddy, -the second addition of soda is necessary. - -In this way a sufficiently accurate estimate of the quantity of soda -required to eliminate the impurities of the feed water can be made and -the due proportion added to the feed water. - -By exercising a little judgment, the use of pure chemicals, with -well cleaned vessels, test tubes, etc., the following reagents will -determine the character of the most important elements which injure the -iron surfaces of a steam boiler. - - Carbonic acid is indicated by baryta water. - Sulphates are indicated by chloride of barium. - Chlorides are indicated by nitrate of silver. - Lime salts are indicated by oxalate of ammonia. - Organic matter is indicated by chloride of mercury. - -The “base” of the better class of the various patented boiler compounds -is tannin (whence tannic acid) and some form of alkali, and if the -compounds were to be deprived of these two elements they would be -absolutely worthless. - -Where they contain, as some certainly do, sal-ammoniac, muriatic, -hydrochloric and sulphuric acids, they cannot but act as boiler -destroying agents. - -Tannin or tannic acid is the principal ingredient used in preparing -leather. It is found in a great variety of plants—sassafras root has -it in large proportion, the gall nut and the bark of various trees, -especially the oak produce it. - -It is the presence of this acid that gives their only value to very -many “compounds,” tan bark, gum catechu (which sometimes contains -one-half part of tannic acid), etc. The acid seems to have but little -effect where large quantities of sulphate of lime are present, but in -waters where carbonate of lime predominates its detersive qualities are -more marked. - -The records of the Patent Office show that one boiler compound -_contains 23 per cent. of catechu_, and others, 60, 81, 5, -respectively, by which may be inferred the large quantity of this -agent, which has been sold in combination with other chemicals, -principally soda. - -NOTE. - -While the product of water steeped in clean tan bark may be favorable -in its action upon boiler incrustation, _it has been found to be very -unsafe, in practice, to use the “tan liquor” taken from the vats_. -The danger arises from the fact that sometimes during the process of -tanning leather, the required acidity cannot be produced by natural -fermentation when sulphuric acid is added, in order to bring the liquor -to its required strength—in due course, this corrosive substance acts -injuriously on the boiler. - - -USE OF PETROLEUM OIL IN BOILERS. - -The use of crude (unrefined) mineral oil in steam boilers is attended -by risks caused by impurities and foreign substances mixed with it. -These are likely to combine with the earthy matter in the water and -tend to form instead of preventing scale; the tar and wax contained in -crude petroleum combine with the sediment in steam boilers, and the -paste prevents the water from reaching and protecting the plates. This -is true particularly in shell boilers which have flat surfaces over the -fire. Refined mineral oil has none of these disadvantages. - -Kerosene oil has all the advantages to be derived from the use of crude -petroleum and the above objections quite removed. - -In one system of the application of steam the use of kerosene and -petroleum cannot be recommended: that is _when live steam is used for -cooking purposes_, the odor from the oil will impregnate the meat and -other products designed for food consumption. - - -KEROSENE OIL IN BOILERS. - -Under certain conditions, and with care and judgment, the use of -refined petroleum has been found to be of great advantage in removing -and preventing scaling in steam boilers. - -There is no well authenticated case where a systematic, regular and -uniform feed of pure kerosene oil to a steam boiler has failed to -operate beneficially upon the scale formation. - -The best results are obtained by the use of the oil _under the same -arrangement that cylinder oil is fed to an engine_. The kerosene is -sometimes introduced through a one-fourth inch branch to the suction -pipe of the feed pump, leading to the vessel containing the oil, -so that any quantity, large or small, can be put into the boiler -simultaneously with the usual feed. The drawback to this arrangement -is that when the feed water heater has to be cleaned, a gallon or more -of the oil is often lost, which together with a very unpleasant odor, -when used in this manner, tends to condemn its use. _But when piped -between the boiler and heater_, these objections cease. We present an -arrangement which is illustrated by cut on page 157. - -This is nothing more than a storage system with sight feed, by use of -which the oil can be fed drop by drop as desired—for each drop of water -entering the reservoir a drop of oil is forced down the small 1/4-in. -pipe, up the glass tube and on into the boiler. - -In piping it is necessary to have the water or larger pipe (1/2 in.) -attached through the lower plug as shown in cut, and the oil as shown, -going through the smaller or 1/4-in. pipe—_i.e._, the oil pipe must, -under all circumstances, be the smaller of the two. - -In the figure is shown a piece of 6-in. gaspipe, about a foot in -length, plugged at each end; the top plug has one opening, for an -inch nipple “a” with top. This opening is to be used in filling the -reservoir with oil. The bottom plug has two holes, one for the 1/2-inch -water pipe, and the second for a small pet cock “B,” to let the water -out, whenever it is necessary to refill the tank with kerosene. The -water gauge connection is the ordinary, cheap brass fixture, with -boxes, nipples, etc., used in boilers, with gasket of rubber bottom -and top of the glass. The glass plainly exhibits the depth of water -and oil in the reservoir as well as the feed of minute drops of oil as -they speed on their beneficent mission softening the injurious scale. -There are the usual 2 valves on the water glass; by opening the lower -one more or less, the amount of oil used can be regulated to a nicety. -The valves can be used to entirely cut off the apparatus at any time -desired. - -[Illustration: METHOD OF FEEDING KEROSENE OIL TO BOILER.—Fig. 69.] - -NOTE.—Should the end of the screw connection inside the holder which -each one of these valves control, not be 1/4 inch, a reduced elbow -should be used, as 1/4-in. pipe will give the best satisfaction when -used as a stand pipe inside the reservoir. - -The quantity of oil to be fed to a boiler is very largely to be -determined by experiment commencing with a minimum and increasing the -amount as found necessary to keep down the scale formation. The use -of 2 qts. of the oil per week has been found to be sufficient for a -boiler 4 feet in diameter and 12 feet long, and three quarts per week -on boilers 5 feet in diameter. This quantity may be regarded as the -smallest advisable to use and from that up to 1 to 2 gallons per diem -in boilers, say of 125 horse power, when pushed to their capacity in -evaporating water. - -The result of careful experiments justifies the use of kerosene, the -scale being less than in four years’ previous experience, and a large -portion of the boiler showing the clean black steel, in as apparently -good condition as when new. - -Despite the small quantity of kerosene used in the boilers in this -case, the odor was perceptible by opening an air valve to any steam -radiator in any of the buildings. When as much as a gallon per week was -used, the odor was very strong, but with one half that amount it was -hardly perceptible, and only to be noticed when an air valve had been -open a long time. And since commencing to use the oil a much greater -deposit of rust scales than usual has been found in the various steam -traps in the buildings, indicating that the oil is also exerting a -cleansing influence on the pipes of the whole system. - -NOTE.—Provision must be made for the removal of the scale as it drops -from the internal surfaces of the boiler, as at times many bushels of -it have been deposited directly over the furnace; hence, if a boiler -is known to be badly incrusted, the kerosene should not be put in the -first time more than three days before it is intended to wash the -boiler. - -NOTE 2.—The safety valve should be opened to allow the escape of the -gas arising from the kerosene before cleaning out the boiler; where a -lighted lamp or candle is used, as it must necessarily be—indeed this -is a precaution which ought always to be observed in all cases, viz., -properly to ventilate boilers, heaters, and tanks of all descriptions -before entering them with lighted lamps and torches. While these gases -are not likely to cause an explosion, they burn quite rapidly and -should be promptly removed without giving opportunity for an accident. - -The accumulation of gas is not confined to the use of kerosene oil for -the prevention of scale in steam boilers, but is also found in flour -mills, confectioners’, conduits for electric wires, brewers’ vats, -etc. So, with common sense precautions, no extra risk is run in using -kerosene oil in steam boilers. - - -MECHANICAL BOILER CLEANERS. - -Owing to the fact (1) that nearly, if not quite all, the impurities -which exist in feed water are set free by a high temperature attained -under pressure; (2) that these impurities are left in the boiler by -the constant use of the steam, there follows the result that the water -remaining is more and more impregnated with the residuum composed of -the foreign matters which (the water removed) constitutes mud, scale, -etc. - -The custom has been and is now to regularly “blow off” one or two -gauges of this water once or twice per day replacing it with fresh -water of less density; that this is a very imperfect method for -removing the foreign matter is readily allowed, besides wasting -absolutely all the units of heat contained in the water blown off. - -Now, within the boiler while in use, under the operation of the fierce -heat of the furnaces, are constant changes in the position of the -water caused by the boiling, by the withdrawal of the steam and by the -constant effort of the hot water to rise and the cold water to fall. -The water thus keeps in circulation everything within the boiler, -including the sediment, _except in places where the water is from -any cause without motion_. In these quiet nooks there is a constant -depositing of the elsewhere active foreign matters contained in the -water, which deposits, in the form of mud and scale, left undisturbed, -causes loss and danger. - -It is in taking advantage of these facts, and of the principles of the -circulation of hot and cold water, that mechanical boiler cleaners are -brought into successful use. - -These devices for the stilling of the water and collection of the -sediment are made in various forms and all sizes and capacities, and -are located at the sides or back of the boiler setting and even on top -of the boiler. There is a system where pipes in a coil are fixed in -the sides of the furnace and exposed to its greatest heat, and which, -owing to their enlarged area, act as most efficient reservoirs. In -all these devices there is an _upflow pipe_ connected with the lower -and coolest water, and a _return pipe_ connecting with the top of the -water where it is hottest. This arrangement assures a constant current -which is more or less rapid according to the intensity of the fire and -which keeps up as long as the firing is done. Where this current passes -through the reservoir, the enlarged area and comparative quiet is -favorable for the deposit of the sediment and in practical experience -it does deposit nearly all of it. The collection of the impurities is -helped by a _funnel-shaped appliance_ placed at the opening of the -upflow pipe, which, aided by the rapid flow of the hot water, carries -the floating scum towards it into the reservoir. Attached to the -reservoir is the blow-off pipe through which the deposited matter is -removed as often as necessary. - -The use of these mechanical cleaners is readily understood: (1) they -provide a place of accumulation for the sediment; (2) they save the -necessity of opening the boilers to remove by hand, the refuse of the -boiler; (3) save fuel by avoiding the necessity of frequent blowing off -one or two gauges of water, and (4) by the preventing the formation of -scale with its attendant evils. - - -SCUMMING APPARATUS. - -In addition to the bottom blow-out apparatus every boiler should be -provided with means for blowing out water from the surface in order -to remove the fine particles of foreign matter floating there, which -afterward settle and consolidate as scale on the heating surfaces. - -[Illustration: Fig. 70. - -_Scum Cock_] - -It consists, in its simplest form, of a pan, or a conical scoop, near -the surface of the water, but below it, connected with a pipe passing -through the boiler-shell, on which is a cock, or valve, for regulating -the escape of the water laden with the impurities deposited in the pan. -There are patented apparatus for this purpose which are well designed -and easily fitted to a boiler. - -The office of the surface blow-off, illustrated in Fig. 70, is to -remove the foreign matter which is precipitated from its solution in -the water. - -A surface blow-off used occasionally will remove the greater portion -of this scum and keep the boilers reasonably free from scale and mud. -Where dirty or muddy water is fed into the boilers the surface blow-off -is one of the cheapest and most efficient means for keeping the boiler -clean. The efficiency of the surface blow-off is not so great as that -of some of the mechanical boiler-cleaners, as by their use it is not -required that any hot water shall be wasted, and this is the greatest -objection to the surface blow-off, as in the hands of some people a -large amount of boiling water is wasted each time it is used. But -both of these arrangements are virtually skimmers, as they remove the -precipitated mineral and vegetable matter from the surface of the water -in the boiler. One does it by blowing out the scum and some water at -the same time, while the mechanical boiler-cleaner removes the scum, -but returns the water to the boiler. - -There are several efficient ways of arranging a surface blow-off. The -principal part of the blow-off is a pan or perforated pipe placed -horizontally at the water level having a pipe leading outside the -boiler to any convenient place where the scum may be blown. When a -perforated pipe is used the action is to force the scum from the top of -the water during the time the valve is open, and blow it through the -pipe. In using an apparatus of this kind it should be blown often, but -only for a moment at a time, as all the scum near the pipe is removed -immediately, and to keep the valve open longer than necessary to remove -the scum near the pipe would allow the escape of clean water or steam -which would be wasteful. If a pan is used and is fastened so that the -top is secured at the ordinary water level, as shown in Fig. 70, the -blow-off pipe leading from near the bottom of the pan, it will be more -efficient than the perforated pipe arrangement as it will not require -to be used so often, and the waste of water and steam will not be so -great. The pan, by producing an eddy in the water, causes all the -scum to gather over the top, and as the water is quiet there it will -gradually settle into the pan, where it will remain as mud. When the -blow-off valve is opened the greater part of the mud which is gathered -is blown out, and but very little water is carried with it. - - -USE OF ZINC IN MARINE BOILERS. - -Zinc has been used in marine boilers for many years, but it was not -until the publication in 1880 of the report of the Admiralty committee -that the use of zinc became general. It has been used in various ways: -1.—Virgin spelter, as imported in oblong slabs of various sizes. -2.—Cast, or remelted zinc. 3.—Cast zinc buttons, generally made from -virgin spelter or new clean zinc trimmings. 4.—Zinc spheres. 5.—Rolled -zinc blocks, generally 12 inches by 6 inches, and thicknesses varying -from 1/4 inch to 1-1/2 inch, generally with a 13/16-inch hole in the -centre. - -It is desirable that close-grained zinc of uniform structure and free -from impurities should be used, and rolled zinc appears to meet this -want. The wear is entirely confined to the surface. It does not appear -to become distorted or broken up. On the contrary, it gradually wastes -away till only a slight shred, a sort of skeleton frame work, remains -to indicate what it has been. - -The primary object in the use of zinc in boilers is the prevention -of corrosion, but it has also some effect in reducing the amount of -incrustation, and rendering it softer and less adherent. - -TABLE - -_Showing Amount of Sediment collecting in a steam boiler when -evaporating 6,000 gallons per week, of 58,318 grains each._ - - - -----------------------+-------------------- - When a gallon of feed | - water evaporated to |The amount of solid - dryness at 212 degrees | matter collecting - Fahrenheit, leaves of |in boiler per week - solid matter in grains:| will be: - -----------------------+---------+---------- - Grains. | Pounds. | Ounces. - 1 | | 13.714 - 2 | 1 | 11.428 - 3 | 2 | 9.143 - 4 | 3 | 6.857 - 5 | 4 | 4.571 - 6 | 5 | 2.285 - 7 | 6 | - 8 | 6 | 13.714 - 9 | 7 | 11.428 - 10 | 8 | 9.142 - 15 | 12 | 13.713 - 20 | 17 | 2.284 - 25 | 21 | 6.855 - 30 | 25 | 11.426 - 35 | 30 | - 40 | 34 | 4.571 - 45 | 38 | 9.143 - 50 | 42 | 13.714 - 55 | 47 | 2.285 - 60 | 51 | 6.857 - 65 | 55 | 11.428 - 70 | 60 | - 75 | 64 | 4.571 - 80 | 68 | 9.143 - 85 | 72 | 13.714 - 90 | 77 | 2.285 - 95 | 81 | 6.857 - 100 | 85 | 11.428 - 110 | 94 | 4.571 - 120 | 102 | 13.714 - 130 | 111 | 6.857 - 140 | 120 | - 150 | 128 | 9.142 - 160 | 137 | 2.285 - 170 | 145 | 11.428 - 180 | 154 | 4.571 - -----------------------+---------+---------- - - - - -BOILER FIXTURES AND BELONGINGS. - - -A boiler is not complete without certain fixtures. There must be -a feed-pump or injector, with a supply-pipe, feed-valve, safety -feed-valve, and check-valve, in order to supply water properly to -the boiler; gauge-cocks, a glass water-gauge, a blow-pipe, with its -valve, to reduce the height of the water in the boiler, or to empty -it entirely; a safety-valve to allow the steam to escape from the -boiler when it exceeds a fixed pressure; a scumming apparatus to remove -the foreign matters from the water as much as possible; a steam-pipe -to convey the steam to the place where it is wanted; man-holes and -hand-holes, with their covers and guards, for examination and cleaning; -a non-corrosive steam-gauge, to accurately indicate at all times the -amount of pressure in the boiler; and a fusible plug to give warning in -case of “low water.” - -Thus we see that in speaking of a boiler, not only the boiler proper is -meant, but also the whole of its fixtures and belongings, of which the -following is only a partial list: - - Feed Pump, - Injector or Inspirator, - Check Valve, - Gauge Cocks, - Glass Water Gauge, - Try Cocks, - Blow-out Apparatus, - Blow-off Valve, - Safety Valve, - Scum Apparatus, - Steam Gauge, - Fusible Plug, - Surface Blow Cocks, - Grate Bars, - Baffle or Shield Plates, - Mud Drum, - Feed Water Heaters, - Boiler Fronts, - Dead Plate, - Steam Pressure Recording - Gauge, - Drain Cock for Steam Gauge, - Steam Trap, - Steam Whistle. - -All these are attachments to the boiler proper, having direct reference -to its internal functions; but in addition there are the lugs, -pedestals, or brackets which support the boiler; the masonry in which -it is set, with its binders, rods, and wall-plates; the boiler front, -with its doors, anchor-bolts, etc.; the arch-plates, bearer-bars, -grate-bars, and dampers, and last, but not least, the chimney. These -are all equally necessary to enable the boiler to perform its duty -properly. And besides, there are required fire-tools, flue brushes and -scrapers, and scaling tools, with hose also, to wash out the boiler, to -say nothing of hammers, chisels, wrenches, etc. - -The fittings and attachments of the marine boiler are similar to those -belonging to the land steam generators, and vary only in accommodating -themselves to their peculiar surroundings. - -The proper operation of the boiler as to efficiency and economy is -largely dependent upon the number, appropriate proportion and harmony -of action of its numerous attachments, and the utmost care and skill -are requisite for designing and attaching them. - -It must not be supposed that a complete list and description of all -steam boiler attachments are here presented—that were a task beyond the -limits of the entire volume. - - -BOILER FRONTS. - -Boiler fronts are made in many different styles, almost every maker -having some peculiar points in design that he uses on his own boilers -and which nobody else uses. - -In the illustrations here given may be seen the four principal designs: - -1. The flush front is shown in Fig. 72. - -2. The overhanging front as seen in Fig. 73. - -3. The cutaway front, Fig. 74. - -4. Fronts with breaching as shown in Fig. 75. - -The flush front is one of the earliest forms of fronts, and though it -often gives good satisfaction, yet it is liable to certain accidents. -[Illustration: Front for Water Tube Boiler.—Fig. 71.] - -[Illustration: Flush Front.—Fig. 72.] - -As will be seen from cut 72, the front of the smoke arch, in this form -of setting, is flush with the front of the brickwork, and the dry sheet -just outside of the front head is built into the brickwork. The heat -from the fire, striking through the brickwork, impinges on this sheet, -which is unprotected by water on the inside. So long as the furnace -walls are in proper condition the heat thus transmitted should not be -sufficient to give trouble; but after running some time bricks are very -apt to fall away from over the fire door, and thus expose portions of -the dry sheet to the direct action of the fire, causing it to be burned -or otherwise injured by the heat, and perhaps starting a leakage around -the front row of rivets when the head is attached to the shell. - -In the overhanging front this tendency is entirely prevented by setting -the boiler _in such a manner that the dry sheet projects out into the -boiler room_. If the brickwork over the fire door falls away when a -boiler is set in this manner, the only effect is to slightly increase -the heating surface. No damage can be done, since the sheet against -which the heat would strike is protected by water on the inside. - -[Illustration: Overhanging Front.—Fig. 73.] - -The objection is sometimes raised against the projecting front, that it -is in the way of the fireman. To meet this point and yet preserve all -the advantages of this kind of front, the cutaway style has come into -use. In this form the lower portion or the front sheet is cut obliquely -away, so that at the lowest point the boiler projects but little beyond -the brickwork. - -[Illustration: Cutaway Front—Fig. 74.] - -It will be noticed that in the flush and overhanging fronts, the doors -open sidewise, swing about on vertical hinges; in the cutaway front -the best way to arrange the tube door is to run a hinge along the top -of it, horizontally, and to have the door open upward. But with such a -disposition of things the door is not easy to handle. For the purpose -of support a hook and chain, hanging from the roof should be provided. - -[Illustration: Front for Manhole.—Fig. 75.] - -Fig. 75 shows a boiler the setting of which is similar in general -design to the other three, except that in the place of a cast-iron -front it has bolted to it a sheet iron breeching that comes down over -the tubes and receives the gases of combustion from them. In Fig. 75 a -manhole is shown under the tubes. This, of course, is not an essential -feature of the breeching, but it will be seen that manholes can readily -be put below the tubes on fronts of this kind, in such a manner as to -be very convenient of access. - -In addition to these more general styles of boiler fronts, there are -fronts designed particularly for patent boilers, water-front boilers, -etc., which are made, very often, in ornamental and attractive designs. -In Fig. 71 is shown a beautiful and appropriate design in use in -connection with water tubular boilers. - - -FURNACE DOORS. - -The chief points to be considered in the design of furnace doors are -to prevent the radiation of heat through them, and to provide for -the admission of air above the burning fuel in order to aid in the -consumption of smoke and unburnt gases. - -In all cases where the doors are exposed to very rough usage—such, -for instance, as in locomotive and marine boilers—the means for -admitting air must be of the simplest, and consist generally of small -perforations as shown in Fig. 76 which represents a front view, and -section of the furnace door of a locomotive boiler. The heat from the -burning fuel is prevented from radiating through the perforation in -the outer door, by attaching to it a second or baffle plate, _a_, at a -distance of about 1-1/2 inches, the holes in which do not coincide in -direction with the door proper. By the constant entry of cold air from -the outside the greater part of any heat which may be communicated to -the door by radiation or conduction is returned to the furnace. - -[Illustration: Fig. 76.] - -Doors similar to the above provide for the constant addition of limited -quantities of fresh air above the fuel, but in actual practice, -however, air is only needed above the fire for a few minutes after -fresh fuel has been thrown on the grates and then is required in -considerable quantities. In the case of land boilers, the furnace -doors of which undergo comparatively mild treatment, it is possible to -introduce the necessary complications to effect this object. - -[Illustration: Fig. 77.] - -Fig. 77 shows an arrangement largely in use in New England, in which, -by means of a diaphragm, the air is passed back and forth across the -heated inner or baffle plate with the very best results. - -The air is first drawn by the natural draught into the hollow space -between the iron door and its lining, through a row of holes _A_, in -the lower part of the door, controlled however, by a slide not shown -in the cut, then caused to flow back and forth across the width of -the door by simply arranged diaphragms, and finally injected into the -furnace through a series of minute apertures drilled in the upper part -of the door liner, as indicated in cut at _B_. - -It will be seen that while the air may enter the door at a low -temperature, it constantly becomes heated during its circulation until -the instant it enters the furnace, it is ready to flash into flame with -intense heat upon its incorporation with the expanding gases of the -furnace. - -An arrangement in common use in Cornish and Lancashire boilers consists -of a number of radial slits in the outer door which can be closed or -opened at will in the same manner as an ordinary window ventilator. -Other and more complicated arrangements have been frequently devised, -which work admirably so long as they remain in order, but the frequent -banging to which furnace doors are subjected, even in factory boilers, -soon deranges delicate mechanism. - -Furnace doors should be made as small as possible considering the -proper distribution of fuel over the grate area, as otherwise the great -rush of cold air, when the door is opened rapidly, cools down the flues -and does considerable injury to tube plates, etc.; for this reason it -is desirable, when grates are over forty inches in width to have two -doors to each furnace, which can be fired alternately. - -The great loss arising from a rush of cold air on opening the -furnace doors for replenishing the fires with fuel has led to costly -experiments to produce “a mechanical stoker,” or self boiler feeding -arrangement for supplying the coal as needed. - - -FUSIBLE PLUGS. - -In some States the insertion of fusible plugs at the highest fire line -in boilers is compelled by law under a heavy penalty. Its design is -to give the most emphatic warning of low water, and at the same time -relieve the boiler of dangerous pressure. - -[Illustration: Fig. 78.] - -[Illustration: Fig. 79.] - -Figs. 78 and 79 exhibit two of the forms most commonly used, and on -the succeeding page, in cut 80, is shown the device in operation where -the water has sunk to a dangerously low level. In the illustration -the device is shown in connection with a locomotive boiler, in the -common tubular boiler the plug is usually inserted in the rear head of -the boiler, so that in case of its operation it will not endanger the -fireman. - -These devices are designed to be screwed into the boiler shell at the -safety line. The Figs. 78 & 79 exhibit their construction. The part -to be screwed into the boiler is called _the shell_ and is commonly -made of brass; the internal part is plug and is made of a soft metal -like banca tin or a compound consisting of lead, tin and bismuth. This -composition melts easily at the proper point to allow escape, where the -water has sunk to a dangerously low level. - -There is considerable diversity in the make up of the material used for -filling the plug, which must not have its melting point at anything -less than the temperature of the steam lest it should “go off” at the -wrong time. - -[Illustration: FUSIBLE SAFETY PLUG - -Fig. 80.] - -If the accident of low water occurs at a time where it is important to -continue operations with the least possible delay, a pine plug may be -driven in the opening left by the melting of the fusible metal. In any -event it is but a short job to renew the fusible cap, it being only -necessary to unscrew the nut and insert a new cap, the rest of the -device remaining intact. - -The plug should be renewed occasionally and the surface exposed inside -the boiler be kept free from scale and deposit. It is to be understood -that the fusible portion extends entirely through the shell of the -boiler and when melted out makes a vent for the water or steam. - -All marine boilers in service in the United States are required to have -fusible plugs, one-half inch in diameter, made of pure tin, and nearly -all first-class boiler makers put them in each boiler they build. - - -GRATE BARS. - -[Illustration: Fig. 81.] - -THE GRATE BARS are a very important part of the furnace appliances. -These consist of a number of cast iron bars supported on iron bearers -placed at and across the front and back of the furnace. Innumerable -forms of grate bars have been contrived to meet the cases of special -kinds of fuel. The type in common use is represented in Fig. 82. - -[Illustration: Fig. 82.] - -These cuts show a side view and a section of a single bar, and a plan -of three bars in position. Each bar is in fact a small girder, the top -surface of which is wider than the bottom. On each bar are cast lugs, -the width of which determines the size of the opening for the passage -of air. This opening varies in width according to the character of the -fuel; for anthracite 3/4 inch is a maximum, while the soft coals 5/8 -to 3/4 inch is often used; for pea and nut coal still smaller openings -than either of those are used, _i.e._ 1/4 and 3/8 inches. For wood the -opening should be a full inch in width. - -For long furnaces the bars are usually made into two lengths, with a -bearer in the middle of the grate, as shown in Fig. 83. As a rule long -grates are set with a considerable slope towards the bridge in order -to facilitate the distribution of the fuel; an inch to a foot is the -rule commonly approved. - -[Illustration: Fig. 83.] - -[Illustration: Fig. 84.] - -_Rocking and shaking grates_ are now very extensively used; these -combine a dumping arrangement, and very largely lessen the great labor -of the fireman, and by allowing the use of slack and other cheap forms -of fuel are very economical. Several patents are issued upon this form -of grate bars all working on essentially the same principle. Fig. 84 -exhibits an efficient form of a shaking grate. As shown in the cut, -the grates are arranged to dump the ashes and clinkers. By the reverse -motion the flat surface of the grates are restored. - -Trouble with grate bars comes from warping or twisting caused by -excessive heat, and burning out, produced by the same cause—this -explains the peculiar shape in which grates are made—very narrow -and very deep. A free introduction of air not only causes perfect -combustion but tends towards the preservation of the bars. - -Grate bars are usually placed so as to incline towards the rear, the -inclination being from one to two inches; this facilitates somewhat the -throwing of the coal into the furnace. - -The proportion between grate and heating surface should be determined -by the kind of fuel to be used. The greatest economy will be attained -when the grate is of a size to cause the fire to be forced, and have -the gases enter the chimney only a few degrees hotter than the water in -the boiler. - -If the grate is too large to admit of forcing the fire, the combustion -is naturally slower, and consequently the temperature in the furnace is -lower, and the loss from the escaping gases is greater. - -It must be borne in mind that the only heat which can be utilized is -that due to the difference in temperature between the fire and the -water in the boiler. For example, if the temperature in the furnace be -975°, and the water in the boiler have a temperature due to 80 pounds -of steam, viz.: 325°, it is evident that the heat which can be utilized -is the difference between them, or 2/3 of the total heat. Now if the -fire be forced, and the furnace temperature raised to 2600°, 7/8 of the -total heat can be utilized; so it can be readily seen that the grate -should be of such a size as to have the fire burn rapidly. - -The actual ratio of grate to heating surface should not in any case -be less than 1 to 40, and may with advantage, in many cases, be 1 to -50. This proportion will admit of very sharp fires, and still insure -the greater portion of the heat being transmitted to the water in the -boiler. - -The water grate bars, invented in 1824, and since frequently applied to -locomotives and marine boilers, do not seem to grow in popular favor, -and are scarcely known in stationary boilers. - -The objections urged against them are the expense of maintenance, their -fittings and attachments, and the possibility of serious consequences -should they rupture or burn out. - - -WATER GAUGE COCKS. - -It is of the first importance that those in charge of a boiler shall -know with certainty the position of the water level within the boiler. - -[Illustration: Fig. 85.] - -These attachments, also called Try cocks, are usually placed in a -conspicuous and accessible position on the front of boilers. They are -so arranged that one will blow only steam, one at the working level of -the water, and the third at the lowest water level or say three inches -above the highest point of the fire line of the boiler. The cut, Fig. -85, exhibits them as commonly arranged. - -It is not essentially requisite, that the cocks themselves should be -placed at the point indicated, so long as they have pipes projecting -internally into the boiler, with their ends corresponding to the height -of water above mentioned. In order that these cocks may readily be -cleaned out, a plug is usually fitted into bit of cock opposite the -port or opening of the plug, upon removing which a pricker can be -readily inserted. - -The gauge or cocks should be tested many times each day, and when -opened the top one should always give _steam_ and the bottom one -_water_. They should be allowed to remain open long enough to make sure -whether steam or water is issuing from the cock. This is a matter of -instruction, but the beginner with a little experience can detect the -difference by the sound. - -In so universal an appliance as this there are very many forms and -arrangements, but they all work upon the same principle as stated -above. - - -GLASS GAUGES. - -These are the second and auxiliary arrangements for ascertaining -the water line. Nearly all boilers are supplied with both try cocks -and glass gauges, and so important is it considered to be correctly -informed as to the water line that a third method consisting of a float -which is carried on the water surface, is sometimes added to the two -named. - -[Illustration: Fig. 86.] - -The glass water gauge _column_ consists of an upright casting bolted to -the front of the boiler, in which are fixed two cocks having stuffing -boxes for receiving the gauge glass. The lower of these cocks is also -fitted with a drain cock for blowing out the glass. - -The try cocks are frequently placed on the above-mentioned standard or -column. - -The action of the gauge glass is to show the level of the water in the -boiler by natural gravitation and the best position for it is in view -of the engine room, as close to the boiler as possible and preferably -in the middle line of its diameter, at such height that its lowest -portion is about two inches above the highest part of the fire line of -the boiler, and its centre, nine inches above that, making the total -visible portion of glass eighteen inches long. - -Glass water gauges sometimes have pipe connections top and bottom. The -object of this arrangement is to have an undisturbed water level in -the glass by carrying one pipe to the steam dome and the other near to -the bottom of the boiler; the one position not being so liable to be -affected by foaming and the other by the boiling of the water. Cocks -should always be fitted to the boiler ends of these pipes, in order -that in case of accident to the pipes, steam and water may be shut off. - -The glasses are liable to burst and become choked up with dirt. -The former defect is easily repaired by shutting off the cocks in -connection with the boiler and putting in a new glass. The mud or -sediment is cleaned out by opening the above-mentioned drain or -blow-out cock and allowing the steam or water, or both, to rush through -the glass, which will effectually blow out all sediment and leave the -glass in good condition again to show the height of the water in the -boiler. - -In opening the cocks connected with the glasses, it should be done -cautiously, as the glass is liable to burst. - -A strip of white running the whole length of the glass on the side -toward the boiler is a great help in observing the variations of the -water line in the tube. - -It is not needed to remove the gauge glasses to clean them. There are -good fixtures in the market that by taking out the plug in the top, -the glass may be cleaned with a bit of wicking on the end of a stick. -A slight scratch will break the glass, hence do not use wire. Use soft -rubber gaskets when setting the glass, screw up until all leaking -stops. Don’t let the glass come in contact with the metal _anywhere_. -Don’t try to reset the glass with an old hard gasket. Two glasses from -the same bundle will not act alike. - -The glasses used to show the water line are made of a soft glass known -as “lead glass,” and are easily cut, or broken square across. Most -of them can be broken by filing a notch at the point at which it is -necessary to break them. After filing the notch, place the thumbs as -if you would break the glass; it will crack easily, and the fracture -be straight and clean. If the tube be brittle, as some are, to avoid -cutting the hands wrap two pieces of paper around the glass, each side -of the notch. If the ends are rough or uneven, they can be made smooth -by filing or by the grindstone. - -The Manchester, Eng., Boiler Association attribute more accidents to -inattention to water gauges than to all other causes put together. It -is, therefore, of much importance that these glasses should be kept -clean. It is not an uncommon thing to go into a boiler room and find -that a leaky stuffing box has allowed the steam or water to blow out, -and, by running down the outside of the glass, leave a deposit of lime -scale. After this deposit has been formed, it is sometimes difficult -to remove—and more than a few glasses have been broken by the engineer -attempting to remove the scale. After this scale has once been formed, -unless it is soft enough to be wiped off with a piece of waste, it -is best to take the glass out and soak or wash it in a solution of -one-half muriatic acid and one-half water until it is clean or the -scale so softened that it may be readily wiped off. To prevent the -scale from again forming and hardening, the glass should be dipped in -glycerine before replacing. - - -THE MUD DRUM. - -The mud drum is attached to a boiler with the expectation that it will -catch and hold the larger portion of the sediment precipitated from -the water. The mud drum to be effective should be protected from the -heat of the fire, for so soon as it receives sufficient heat to boil -the water within it can no longer serve the purpose for which it was -intended as all the sediment which may have gathered would be expelled -by the ebullition of the water. When the drum is located under the -boiler it is not in a good position to catch the sediment, as the -boiling water produces sufficient current to carry the sediment to the -top, or keep it violently agitated, so that there is little opportunity -for it to be deposited anywhere so long as the boiler is making steam. -Afterward when the water is quiet the sediment for the most part is -deposited on the tubes and the curve of the shell; the small portion -falling into the neck of the drum serves principally to show the -inefficiency of the device. Located under the boiler as it generally -is, makes it extremely difficult to get at for examination, and as -a consequence of its being enclosed, as it must be, to be of much -importance, it is subject to greater deterioration than would otherwise -be the case, and as the enclosure to be most efficient would enclose -the neck also, the difference of expansion at or near the junction -would soon produce leaking if not worse. When the mud drum is located -outside the boiler walls where it would be most efficient, if properly -connected, it loses its identity and becomes a mechanical boiler -cleaner. In consequence of these drawbacks the mud drum is becoming -antiquated as a boiler appliance, and is now seldom used. - - -BAFFLE PLATES. - -These are a device sometimes used inside steam boilers to check the too -sudden flow of steam towards the exit pipe, they are simply plate to -baffle the rush of the steam so as to avoid foaming. - -In Fig. 90 baffle plate is illustrated by the division casting against -which the steam strikes on its passage from the boiler to the engine. -The liners or inner plates of the boiler doors are baffle plates. - - -DEAD PLATE. - -This is a flat plate of iron immediately inside the furnace door and is -used in many boilers in order to insure the more perfect combustion of -the coal. - -When the fresh fuel is laid on, it is placed on the dead plate instead -of on the grate; in this position the coal is coked, the gases from -the coal being ignited as they pass over the already intensely hot -fuel in the furnace, the fuel from the dead plate is pushed forward to -make place for another charge to be put on the dead plate. But more -frequently, as elsewhere described, the fuel is thrown over and across -the dead plate directly upon the hot fire. - - -STEAM WHISTLES. - -These are of two kinds, known as the bell-whistle and organ-tube -whistle; the latter is now fast superseding the former on account of -the simplicity of construction and superior tone. An improved form has -a division in the tube so as to emit two distinct notes, which may be -in harmony, or discord, and when sounded together may be heard a long -distance. - -It is important that the whistle shall sound as soon as the steam -is turned on; to ensure this great care must be taken to keep the -whistle-pipe free from water. - - -THE STEAM GAUGE. - -The principle of construction of the dial steam gauge is, that the -pressure may be indicated by means of a pointer in a divided dial -similar to a clock face, but marked in division, indicating pounds -pressure per square inch instead of hours and minutes. - -Figs. 87 and 88 show the ordinary style of gauge which consists of an -elliptical tube, connected at one end to a steam pipe in communication -with the boiler pressure and at the other end with gearing to a pointer -spindle as shown in cut. - -An inverted syphon pipe is usually formed under the gauge, its object -being to contain water and thus prevent the heat of the steam injuring -the machinery of the gauge, or distorting its action by expansion. - -[Illustration: Fig. 87.] - -[Illustration: Fig. 88.] - -[Illustration: Fig. 89.] - -A small drain cock should be fitted to the leg of the syphon of a steam -gauge, leading to the boiler, at a level with the highest point the -water can rise in the other leg, otherwise an increased pressure will -be indicated, due to the head of water which would otherwise collect in -the boiler leg of the syphon. - -Steam gauges indicate the pressure of steam above the atmosphere only, -the total pressure being measured from a perfect vacuum which will add -14-7/10 lbs. on the average to the pressure shown on the steam gauge. - -These gauges are apt to get out of order in consequence of water -lodging in the end of the heat tube and corroding the latter. It may -be easily known when they are out of order by raising the pressure of -the steam in the boiler and watching when it commences to blow off at -the safety valve, and then noting the position of the index finger. The -pressure registered by the finger should, of course, then correspond -with the known blow off pressure of the valves; if it does not, one or -the other or both of these instruments must be out of order; therefore, -when this is the case and a disagreement occurs, the steam gauge may be -presumed to need correction. - -It should also be noted that the steam gauge finger points to zero when -steam pressure is cut off. A two-way cock should be used for closing -the connection between the steam gauge and the boiler, and at the same -time to let air into the steam gauge. - -The steam should never be allowed to act directly on a steam gauge when -located in cold situations where they are liable to freeze. The valve -on the boiler should be closed and the water allowed to drip out, and, -before the steam is turned on from the boiler, the drip on the gauge -should be closed, in order that sufficient steam may be condensed in -the pipe to furnish the quantity of water necessary to keep the steam -from striking the gauge. - - -_A ready method for being always able to prove the correctness of your -steam gauge._ - -When steam is at some point not over half the usual pressure, place the -ball on the safety valve at the point where it commences to blow off -and mark the place. Move the ball twice as far from the fulcrum as this -mark, and it should blow off at twice the pressure as indicated by the -gauge, or it is not right. Any other relative distance may be used to -advantage. - - -STEAM SEPARATOR. - -This appliance, which is also called an interceptor or catch water, is -generally a T shaped pipe. - -[Illustration: Fig. 90.] - -This, although not a boiler fixture or fitting, is intimately connected -with them: it is an appliance fast coming into use both for land and -marine engines, to guard against the danger to steam engine cylinders -arising from “the priming” of the boilers when the steam is used at a -high pressure with high speed of the piston. - -The separator is usually placed in the engine room, so as to be well -in sight. The steam is led down the pipe round a diaphragm plate and -then up again to the engine steam pipe. By this means any priming or -particles of water that may be brought from the boiler with the steam -will fall to the bottom of the interceptor or catch water, from whence -it can be blown out, according to the arrangement of the pipes, by -opening the drain cock fixed on the bottom. It has a water gauge fixed -on the lower end, so as to show whether water is accumulating; and the -engineers attention is required to see that this water is from time to -time blown off. - -In the illustration, Fig. 90, is shown the simplest form in which the -device can be made. The arrows exhibit the direction in which the steam -travels, the aperture whence the water is to be blown out and the -place for attachment of a water column. In practical construction the -separator should have a diameter twice that of the steam pipe and be -2-1/2 to 3 diameters long. It is often made with a round top and flat -bottom and sometimes with both ends hemispherical. The division plate -should extend half the diameter of the steam pipe below the level of -the bottom of the steam pipe. - -In Fig. 91 is shown an improved form of a steam separator which -consists of a shell or casing in which there is firmly secured a -double-ended cone. On this cone there are cast a number of wings, -extending spirally along its exterior. On entering the separator the -steam is spread and thrown outward by the cone and given a centrifugal -motion by the spiral wings. These wings are constructed with a curved -surface. - -It will be noticed that the steam on entering the separator is -immediately expanded from a solid body into an annular space of equal -volume to the steam pipe, whereby its particles are removed from the -centre and thus receive a greater amount of centrifugal motion. The -entrained water or grease, etc., is thus precipitated against, and -flows along the shell of the separator, and is collected in a well of -ample proportions at base of separator, where it is entirely isolated -from the flow of dry steam. - -[Illustration: Fig. 91.] - - -SENTINEL VALVE. - -It was formerly required for each marine boiler to have a small valve -loaded with a weight to a few pounds per square inch above the working -pressure, so that in case of the safety valves sticking fast and the -gauge being false, an alarm might be given when there was an excess of -pressure. Such valves were about 3/4 inch in diameter and sometimes -as small as 3/8. An arrangement of a small safety valve attached to -a whistle has been introduced, but with advances in other directions -relating to safety these specialties are now getting to be only known -by name. - - -DAMPER REGULATORS. - -These are well-known devices for so controlling the draught of the -chimney that the steam pressure in the boiler will be increased or -decreased automatically, that is, without the aid of a person. The -regulator shown in Fig. 92, which is one of many excellent forms on the -market, has the power to move the damper in both directions by water -pressure, exerting a force on the end of the lever of nearly 200 lbs., -thus compelling a certain and positive motion of the damper when a -variation in the boiler pressure takes place. It will open or close the -damper upon the variation of less than one pound of pressure. The close -regulation affords a test for the correctness of the steam gauge. - -[Illustration: Fig. 92.] - -This regulator, by using the water pressure from the boiler as a motive -power, becomes a complete engine without the connecting rod and crank, -having a balanced piston valve, the valve stem of which is enlarged -where it passes through the upper end of the chest into a piston of -small area, working in a small open ended cylinder cast on the chest. -The pressure forcing this piston outward is counterbalanced by weights -as shown in illustration. - -The differential motion is accomplished by the device shown at the top -of small cylinder. - - -FUEL ECONOMIZER AND FEED WATER PURIFIER. - -This device, shown in Fig. 93, is designed to utilize the waste -products of combustion as they pass from the furnace to the chimney. -Its use permits a high and consequently efficient temperature under the -boilers and yet saves the excess of heat. It acts also as a mechanical -boiler cleaner, furnishing a settling chamber for the deposit of the -impurities separated by the heat which nearly equals that of the live -steam in the boiler. This device adds largely to the water capacity of -the boiler, frequently containing one-half the weight of the water held -in the boiler itself. - -It will be readily understood that the openings between the vertical -tubes are ample for the chimney flue area and that the device is -located between the chimney and the boiler, with the waste furnace heat -passing between the tubes. - -[Illustration: Fig. 93.] - -The economizer shown in Fig. 93 consists of sections of vertical -4-1/2″ boiler tubes fitted to their top and bottom headers by taper -joints. The top headers are provided with caps over each tube to permit -cleaning out the sediment and remove and replace any tube that may -become damaged. The several top headers are connected together at one -end by lateral openings and the bottom headers are also connected as -shown in cut, having hand holes opposite each bottom header to provide -for cleaning out. - -_Mechanical scrapers_ are made to travel up and down each tube to keep -them clear of soot. These are controlled by an automatic mechanism and -driving head, as shown in Fig. 93. - -The important features about the economizer are, 1, its adaptability -to any type of boiler, 2, the saving attained by utilizing that heat -which has necessarily been an almost total waste, 3, the purifying of -the water by means of the intense heat and slow circulation of the feed -water. - - -SAFETY VALVES. - -[Illustration: Fig. 94. - -(SECTIONAL VIEW.)] - -_The safety valve_ is a circular valve seated on the top of the boiler, -and weighted to such an extent, that when the pressure of the steam -exceeds a certain point, the valve is lifted from its seating and -allows the steam to escape. Safety valves can be loaded directly with -weights, or the load can be transmitted to the valve by a lever. Again, -the end of the lever is sometimes held down by a spring, or the spring -may be applied directly to the valve seat. - -Fig. 94 (2 views) exhibits _a spring loaded safety valve_. These are -generally provided with a reaction lip, surrounding the seat, which -causes them to open much further, and thus enables them to discharge a -larger volume of steam than a lever valve of equal diameter. - -The operation can be easily understood by examining the figures. As -soon as the steam pressure is high enough to lift the valve disc clear -from its seat, the steam will escape around the valve seat as in an -ordinary lever safety valve, but instead of escaping directly into -the atmosphere, the current of steam is turned downward against the -reaction lip, by the curved projection on the valve disc, which can be -seen in the figure. The steam pressure is thus assisted in holding the -valve open, as well as raising it much higher, giving a larger opening -than would be the case if the valve were lifted by the pressure alone. - -Spring loaded valves are mostly used on marine boilers, locomotives and -portable boilers, and wherever outside disturbances interfere with the -action of a weight. - -_A “pop” safety valve_ is a common form of safety valve and takes its -name from the fact that it takes a little more pressure to raise it off -its seat than what it is set at, consequently it releases itself with a -“pop.” - -[Illustration: Fig. 95.] - -Fig. 95 shows a form of dead weight safety valves when _a_ is the valve -which rests on the seating _b_. - -The valve is attached to the circular casting A, A, A, so that both -rise and fall together. The weights W, W, etc., are disposed on the -casting in rings, which can be adjusted to the desired blow off -pressure. Owing to the center of gravity of the casting and weight -being below the valve, the latter requires no requires no guides to -keep it in position. This is a great advantage as guides frequently -stick, and prevent the valve from acting. Another advantage of this -form of valve is, that it is difficult to tamper with. For instance, a -four-inch valve, intended to blow off at 100 lbs. per square inch would -require weight of over 1,200 lbs., which require a considerable bulk. -An unauthorized addition of a few pounds to such a mass would make no -appreciable addition to the blowing off pressure, while any effectual -amount added to the weight would be immediately noticed. It is quite -different with the lever safety valve about to be described, a small -addition to the weight at the end of the lever is multiplied several -times at the valve. - - -U. S. RULES RELATING TO SAFETY VALVES. - -Extract from rules and regulations passed and approved Feb. 25, 1885, -by the United States Board of Supervising Inspectors of Steam Vessels: - -SECTION 24. “Lever safety valves to be attached to marine boilers shall -have an area of not less than one square inch to two square feet of the -grate surface in the boiler, and the seats of all such safety valves -shall have an angle of inclination of forty-five degrees to the centre -line of their axis. - -“The valves shall be so arranged that each boiler shall have one -separate safety valve, unless the arrangement is such as to preclude -the possibility of shutting off the communication of any boiler with -the safety valve or valves employed. This arrangement shall also apply -to lock-up safety valves when they are employed. - -“Any spring-loaded safety valves constructed so as to give an increased -lift by the operation of steam, after being raised from their seats, -or any spring-loaded safety valve constructed in any other manner, or -so as to give an effective area equal to that of the aforementioned -spring-loaded safety valve, may be used in lieu of the common -lever-weighted valve on all boilers on steam vessels, and all such -spring-loaded safety valves shall be required to have an area of not -less than one square inch to three square feet of grate surface of the -boiler, and each spring-loaded valve shall be supplied with a lever -that will raise the valve from its seat a distance of not less than -that equal to one-eighth the diameter of the valve opening, and the -seats of all such safety valves shall have an angle of inclination -to the centre-line of their axis of forty-five degrees. But in no -case shall any spring-loaded safety valve be used in lieu of the -lever-weighted safety valve, without first having been approved by the -Board of Supervising Inspectors.” - -The following size “Pop” Safety Valves are required for boilers having -grate surfaces as below: - - 2 inch “Pop” Valve for 9.42 square feet of grate surface. - 2-1/2 inch “Pop” Valve for 14.72 square feet of grate surface. - 3 inch “Pop” Valve for 21.20 square feet of grate surface. - 4 inch “Pop” Valve for 37.69 square feet of grate surface. - 5 inch “Pop” Valve for 58.90 square feet of grate surface. - 6 inch “Pop” Valve for 84.82 square feet of grate surface. - -PROFESSOR RANKIN’S RULE.—Multiply the number of pounds of water -evaporated per hour by .006, and the product will be the area in square -inches of the valve. - -The U. S. Steamboat Inspection Law requires for the common lever valve -one square inch of area of valve for every two square feet of area of -grate surface. - -United States Navy Department deduced from a series of experiments the -following rule: Multiply the number of pounds of water evaporated per -hour by .005, and the product will be the area of the valve in square -inches. - -Rule adopted by the Philadelphia Department of Steam Engine and Boiler -Inspection: - -1. Multiply the area of grate in square feet by the number 22.5. 2. Add -the number 8.62 to the pressure allowed per square inch. Divide (1) by -(2) and the quotient will be the area of the valve in square inches. -This is the same as the French rule. - -The maximum desirable diameter for safety valves is four inches, for -beyond this the area and cost increase much more rapidly than the -effective discharging around the circumference. - -There should not be any stop valve between the boiler and safety valve. - -The common form of safety valve is shown in Fig. 96. - -Here the load is attached to the end _B_ of the lever _A_, _B_, the -fulcrum of which is at _c_. The effective pressure on the valve, and -consequently the blowing off pressure in the boiler can be regulated -within certain limits, by sliding the weight _W_ along the arm of the -lever. In locomotive engines, as well as on marine boilers, the weight -would on account of the oscillations, be inadmissible and _a spring_ is -used to hold down the lever. - -In the calculations regarding the lever safety valve, there are five -points to be determined, and it is necessary to know four of these in -order to find the fifth. These are: (1) The Steam Pressure, (2) The -Weight of Ball, (3) The Area of Valve, (4) The Length of Lever, (5) The -Distance from the Valve Centre to the Fulcrum. - -[Illustration: Fig. 96.] - -In making these calculations it is necessary to take into account the -load on the valve due to the weight of the valve-stem and lever. The -leverage with which this weight acts is measured by the distance of its -centre of gravity from the fulcrum. The centre of gravity is found by -balancing the lever on a knife edge, and the weight of the valve-stem -and lever can be found by actual weighing. This load can also be found -by attaching a spring balance to the lever exactly over the centre of -the valve stem when they are in position. The following examples will -be computed under these conditions: (1) Steam Pressure, 120 pounds; (2) -Weight of Ball, 100 pounds; (3) Weight of Valve and Lever, 60 pounds, -weighed in position; (4) Length of Lever, 45 inches; (5) Length of -Distance from Valve Centre to Fulcrum, 5 inches; (6) Area of Valve, 8 -square inches. - -_To find the area of the valve:_ - -RULE.—Multiply the length of the lever by the weight of the ball, -and divide the product by the distance from the valve centre to the -fulcrum, and to the quotient add the effective weight of the valve and -lever, and divide the sum by the steam pressure. - -_Example._ - - 45 inches, length of the lever, - 100 pounds, weight of the ball, - ---- - Fulcrum, 5 in. )4500 - ---- - 900 - 60 pounds, weight of valve and lever, - ---- - Steam pressure 120 lbs. )960 (8 square inches, area of valve. - 960 - -_To find the pressure at which the valve will blow off:_ - -RULE.—Multiply the length of the lever by the weight of the ball; -divide this product by the distance from the valve centre to the -fulcrum, and to the quotient add the effective weight of the lever and -valve, and divide the sum by the area of the valve. - -_Example._ - - 45 inches, length of lever, - 100 pounds, weight of ball, - ---- - Fulcrum, 5 in. )4500 - ---- - 900 - 60 pounds, weight of valve and lever, - ---- - Area of Valve 8 ) 960 - ---- - 120 pounds, pressure at which valve will blow. - -_To find the weight of ball:_ - -RULE.—Multiply the steam pressure by the area of the valve, and from -the product subtract the effective weight of the valve and lever, then -multiply the remainder by the distance from the valve centre to the -fulcrum, and divide the product by the length of the lever. - -_Example._ - - 120 pounds, steam pressure, - 8 inches, area of valve, - ---- - 960 - 60 pounds, weight of valve and lever, - ---- - 900 - 5 inches, fulcrum, - ---- - Length of lever, 45 in. )4500 - ---- - 100 pounds, weight of ball. - -_To find the length of lever:_ - -RULE.—Multiply the steam pressure by the area of the valve, and from -the product subtract the effective weight of the valve and lever, then -multiply the remainder by the distance from the valve centre to the -fulcrum, and divide the product by the weight of the ball. - -_Example._ - - 120 pounds, steam pressure, - 8 inches, area of valve, - ---- - 960 - 60 pounds, weight of valve and lever, - ---- - 900 - 5 - ---- - 100)4500(45 length of lever. - -Every boiler should be provided with two safety valves, one of which -should be put beyond the control of the attendant. - -Safety valves that stick will do so even though tried every day, if -they are simply lifted and dropped to the old place on the seat again. -_If a boiler should be found with an excessively high pressure, it -would be one of the worst things to do to start the safety valve from -its seat unless extra weight was added_, for should the valve once -start, it would so suddenly relieve the boiler of such a volume of -steam as would cause a rush of water to the opening, and by a blow, -just the same as in water hammer, rupture the boiler. - -Such a condition is very possible to occur of itself when a safety -valve sticks. The valve holds the pressure, that gets higher and -higher, until so high that the safety valve does give way and allows so -much steam to escape that the sudden changing of conditions sets the -water in motion, and an explosion may result. - -The noise made by a safety valve when it is blowing off may be -regarded in two ways. First, by it is known that the valve is capable -of performing its proper function, and that there is, therefore, a -reasonable assurance that no explosion will result from excessive -pressure of steam or other gas, and on the other hand too much noise of -this kind indicates wasted fuel. - -The hole of the safety valve may be 2, 3 or 4 inches; that does not -say that the area is 3.1416, 7.06 or 12.56 square inches, but the area -is that which is inside of the joint. The valve opening may be, say -2 inches, but _the circle of contact of valve to seat_ may be of an -average diameter of 2-1/8 inches, if so, all the close calculations -otherwise will not avail. In the first place, the area of 2 inches -equals 3.1416; that of 2-1/8 diameter equals 3.5466, showing a -difference of .4 square inches. - -NOTE. - -Very extended rules issued by the U. S. Government for calculating -the safe working pressure, dimensions and proportions of the safety -valves for marine boilers are reprinted in “Hawkins’ Calculations” for -engineers. - -When a safety valve is described as a “2 inch safety valve,” etc., -it means that two inches is _the diameter_ of the pipe; hence the -following rule and examples for finding the area. - - -RULE FOR FINDING AREA OF VALVE OPENING. - -Square the diameter of the opening and multiply the product by the -decimal .7854. - -EXAMPLE. - -What is the area of a three inch valve? Now then: - - 3 × 3 = 9 × .7854 = 7.06 square inches, Ans. - -NOTE.—A shorter method of calculating by .7854 in larger sums is to -multiply by 11 and divide by 14, for decimal .7855 = the fraction -11/14th. Note: .7854 is the area of a circular inch. - -When valves rise from their seats under increasing steam pressure -they do so by a constantly diminished ratio which has been carefully -determined by experiment and reduced to the following table. - - +----------------+----------------+ - |Pressure in Lbs.| Rise of Valve. | - +----------------+----------------+ - | 12 | 1-36 | - | 20 | 1-48 | - | 35 | 1-54 | - | 45 | 1-65 | - | 50 | 1-86 | - | 60 | 1-86 | - | 70 | 1-132 | - | 80 | 1-168 | - | 90 | 1-168 | - +----------------+----------------+ - -The following useful table was prepared by the Novelty Iron Works, New -York. - - +----------------+----------------+ - |Boiler Pressure |Area of Orifice | - | in Lbs. Above | in Sq. In. for | - |the Atmosphere. |Each Sq. Ft. of | - | |Heating Surface.| - +----------------+----------------+ - | 0.25 | .022794 | - | 0.5 | .021164 | - | 1. | .018515 | - | 2. | .014814 | - | 3. | .012345 | - | 4. | .010582 | - | 5. | .009259 | - | 10. | .005698 | - | 20. | .003221 | - | 30. | .002244 | - | 40. | .001723 | - | 50. | .001389 | - | 60. | .001176 | - | 70. | .001015 | - | 80. | .000892 | - | 90. | .000796 | - | 100. | .000719 | - | 150. | .000481 | - | 200. | .000364 | - +----------------+----------------+ - - -FEED WATER HEATERS. - -[Illustration: Fig. 97.] - -There are two forms of feed water heaters: (1) _The closed heater_, -where the feed water passes through tubes, which are enclosed in a -shell, through which the exhaust steam passes.(2) _The open heater_, in -which the steam and water come into contact. In the latter the water is -sprayed into a space, through which the exhaust steam passes, or is run -over a number of inclined perforated copper plates, mingled with the -exhaust steam. - -The original feed water heater called a “pot heater,” consisted of -a vessel so constructed that the feed water was sprayed through the -exhaust steam into a globe formed tank, from the bottom of which the -heated water was pumped into the boiler; its name was originally the -“pot heater,” but as it was open to the air through the exhaust pipe, -it was, with its successively improved forms called the open heater. - -All the heat imparted to the feed water, before it enters the boiler, -is so much saved, not only in the cost of fuel, but by the increased -capacity of the boiler, as the fuel in the furnace will not have this -duty to perform. There are two sources of waste heat which can be -utilized for this purpose: the chimney gases and the exhaust steam. -The gases escaping to the chimney after being reduced to the lowest -possible temperature contain a considerable quantity of heat. This -waste of heat energy may be largely saved by the device illustrated on -page 186. - -[Illustration: Fig. 98.] - -How much saving is obtained under any given condition is a question -requiring for its solution a careful calculation of all of the -conditions which have a bearing on the subject. Exhaust steam under -atmospheric pressure only has a sensible temperature of 212 degrees, -but exhaust steam contains also a large number of heat units which are -given up when the steam is condensed into water; for this reason it -might be thought possible to raise the temperature of the feed water a -few degrees higher even than the sensible temperature of the exhaust -steam. But this should not be expected, on account of the radiation of -heat that would occur above that of the steam. - -The steam which escapes from the exhaust pipe dissipates into the -atmosphere or discharges into the condenser over nine tenths of the -heat it contained when leaving the boiler. This can be best utilized -by _exhaust feed water heaters_, for the use of live steam heaters -represents no saving in fuel, as all the heat imparted to the feed -water by their use comes directly from the boiler. The purpose for -which they are used is to elevate the temperature of the feed water -above the boiling point, so as to precipitate the sulphate of lime -and other scale forming substances, and prevent them from entering -the boiler. Neither does the heat in the feed water introduced by -an injector represent saving, as it comes from the boiler and was -generated by the fuel. - -It is important to note these two statements: 1, That neither live -steam feed water heaters, nor 2, injectors save the heat from the -escaping steam. - -It is also well to remember that it requires _a pound of water_ to -absorb 1.146 heat units, and that this quantity of heat is distributed -through the whole quantity of water, and _as a pound of steam is the -same as a pound of water_, it may be understood that at 212° each pound -of exhaust steam contains 1,146 heat units; ten pounds of steam contain -11,460 heat units distributed through the mass, etc.: thus, to explain -still further: - -To evaporate water into steam, it must first be heated to the boiling -point, and then sufficient heat still further added to change it from -the liquid to the gaseous state, or steam. Take one pound of water at -32 degrees and heat it to the boiling point, it will have received 212° -- 32° = 180 heat units. A heat unit being the amount of heat necessary -to raise one pound of water through one degree at its greatest density. -To convert it into steam after it has been raised to the boiling point, -requires the addition of 966 heat units, which are called latent, as -they cannot be detected by the thermometer. This makes 180 + 966 = -1146 heat units, which is the total heat contained _in one pound of -water_ made into steam at the atmospheric pressure. And at atmospheric -density the volume of this steam is equal to 26.36 cubic feet, and this -amount of steam contains 1,146 units of heat, distributed throughout -the whole quantity, while the temperature at any given point at which -the thermometer may be inserted is 212 degrees. If two pounds of water -be evaporated, making a volume of 52.72 cubic feet, then the number of -heat units present would be doubled, while the temperature would still -remain at 212, the same as with one pound. - -If by utilizing the heat that would otherwise go to waste, the -temperature of the feed water is raised 125 degrees, the saving would -be 125/1146 of the total amount of heat required for its evaporation, -or about 11 per cent. Thus it can be seen the percentage of saving -depends upon the initial temperature of the feed water, and the -pressure at which it is evaporated. - -For example, a boiler carrying steam at 100 pounds pressure has the -temperature of the feed water raised from 60 to 200 degrees, what is -the percentage of gain? - -By referring to a table pressure of “saturated steam,” it will be seen -that the total heat in steam at 100 pounds pressure is 1185 heat units. -These calculations are from 32 degrees above zero, consequently the -feed must be computed likewise. - -In the first case, the heat to be supplied by the furnace is the total -heat, less that which the feed water contains, or 1185 - 28 = 1157 -heat units. In the second case it is 1185 - 168 = 1017 heat units, -the difference being 1157 - 1017 = 140, which represents a saving of -140/1157 or about 12 per cent. - -Where feed water is heated no more than 20 degrees above its normal -temperature the gain effected cannot amount to more than 2%, not -sufficient to pay for the introduction and maintenance of a feed water -heating device, no matter how simple, but if the temperature of the -water can be increased 60 degrees the gain will be in the neighborhood -of 5%. To make feed water heating practical and economical it would be -necessary to increase the temperature of the water about 180 degrees at -least, and to do this, using the exhaust from a non-condensing engine -without back pressure, would require such a capacity of heater as would -give fully 10 square feet of heating surface to each horse power of -work developed, and to raise the temperature above this would require a -certain amount of back pressure or an increased capacity of heater, so -that the subject resolves itself into a question of large capacity of -heater, or a higher temperature of the exhaust steam, which could only -be obtained through a given amount of back pressure. - -In the same way has been calculated the following table, showing -percentages of saving of fuel by heating feed-water to various -temperatures by exhaust steam, otherwise waste: - -_Percentage of saving._ (_Steam at 60 pounds gauge pressure._) - - -----+-------------------------------------------------------------- - Final| Initial Temperature of Water (Fahrenheit). - Temp.+--------+--------+--------+--------+--------+--------+-------- - Fahr.| 32 Deg.| 40 Deg.| 50 Deg.| 60 Deg.| 70 Deg.| 80 Deg.| 90 Deg. - -----+--------+--------+--------+--------+--------+--------+-------- - 60 | 2.39 | 1.71 | 9.86 | … | … | … | … - 80 | 4.09 | 3.43 | 2.59 | 1.74 | 0.88 | … | … - 100 | 5.79 | 5.14 | 4.32 | 3.49 | 2.64 | 1.77 | .90 - 120 | 7.50 | 6.85 | 6.05 | 5.23 | 4.40 | 3.55 | 2.68 - 140 | 9.20 | 8.57 | 7.77 | 6.97 | 6.15 | 5.32 | 4.47 - 160 | 10.90 | 10.28 | 9.50 | 8.72 | 7.91 | 7.09 | 6.26 - 180 | 12.60 | 12.00 | 11.23 | 10.46 | 9.68 | 8.87 | 8.06 - 200 | 14.36 | 13.71 | 13.00 | 12.20 | 11.43 | 10.65 | 9.85 - 220 | 16.00 | 15.42 | 14.70 | 14.00 | 13.19 | 12.33 | 11.64 - -----+--------+--------+--------+--------+--------+--------+-------- - |100 Deg.|120 Deg.|140 Deg.|160 Deg.|180 Deg.|200 Deg.| - -----+--------+--------+--------+--------+--------+--------+-------- - 60 | … | … | … | … | … | … | - 80 | … | … | … | … | … | … | - 100 | … | … | … | … | … | … | - 120 | 1.80 | … | … | … | … | … | - 140 | 3.61 | 1.84 | … | … | … | … | - 160 | 5.42 | 3.67 | 1.87 | … | … | … | - 180 | 7.23 | 5.52 | 3.75 | 1.91 | … | … | - 200 | 9.03 | 7.36 | 5.62 | 3.82 | 1.96 | … | - 220 | 10.84 | 9.20 | 7.50 | 5.73 | 3.93 | 1.98 | - -----+--------+--------+--------+--------+--------+--------+-------- - -A good feed-water heater of adequate proportions should readily raise -the temperature of feed-water up to 200° Fahr., and, as is seen by -inspection of the table, thus effect a saving of fuel, ranging from -14.3 per cent. to 9.03 per cent., according as the atmospheric or -normal temperature of the water varies from 32° Fahr. in the height of -winter, to 100° Fahr. in the height of summer. - -The percentage of saving which may be obtained from the use of exhaust -steam for heating the feed water, with which the boiler is supplied, -will depend upon the temperature to which the water is raised, and -this, in turn, will depend upon the length of time that the water -remains under the influence of the exhaust steam. This should be as -long as possible, and unless a sufficient amount of heating surface is -employed in the heater best results cannot be expected. - -It does not necessarily require all the exhaust steam—or the whole -volume of waste steam passing from the engine to bring the feed water -up to the temperature desired, and the larger the heating appliance the -smaller proportion is needed—hence heaters are best made with two exits -nicely proportioned to avoid back pressure and at the same time utilize -enough of the exhaust to heat the feed water. - -An impression prevails among many who are running a condenser on their -engine that a feed water heater can not be used in connection with it; -large numbers of heaters running on condensing engines with results as -follows: the feed water is delivered to the boiler at a temperature of -150° to 160° Fahr., depending on the vacuum: the higher the vacuum the -less the heat in the feed water. - -A heater applied to a condensing engine generally increases the vacuum -one to two inches. - -When cold water is used for the feed water, the saving in fuel by the -use of the heater is from 7 to 14 per cent. - -When feed water is taken from the hot well, it will save 7 to 8 per -cent. - -Where all the steam generated by a boiler is used in the engine and the -exhaust passed through a heater it is found by actual experiment, where -iron tubes are used in the heater, that approximately ten square feet -of heating surface will be required for each 30 lbs. of water supplied -to the boiler at a temperature of 200 degrees Fahr. - -Ten square feet of heating surface in the feed water heater also -represents one horse power. - - -CAPACITY OF CISTERNS. - -The following table gives the capacity of cisterns for each twelve -inches in depth: - - _Diameter._ _Gallons._ - 25 feet 3671 - 20 „ 2349 - 15 „ 1321 - 14 „ 1150 - 13 „ 992 - 12 „ 846 - 11 „ 710 - 10 „ 587 - 9 „ 475 - 8 „ 376 - 7 „ 287 - 6-1/2 „ 247 - 6 „ 211 - 5 „ 147 - 4-1/2 „ 119 - 4 „ 94 - 3 „ 53 - 2-1/2 „ 36 - 2 „ 23 - -Supposing it was required to find the weight of the water in any -cistern or tank; it can be ascertained by multiplying the number of -gallons by the weight of one gallon, which is 8-1/3 pounds, 8.333. For -instance, taking the largest cistern in the above table containing 3671 -gallons: 3671 × 8.33 = 30579.43 pounds. - -The table above gives the capacities of round cisterns or tanks. If the -cistern is rectangular the number of gallons and weight of water are -found by multiplying the dimensions of the cistern to get the cubical -contents. For instance, for a cistern or tank 96 inches long, 72 inches -wide, and 48 inches deep, the formula would be: 96 × 72 × 48 = 331,776 -cubic inches. - -As a gallon contains 231 cubic inches; 331,776 divided by 231 gives -l,436 gallons, which multiplied by 8.33 will give the weight of water -in the cistern. - -For round cisterns or tanks, the rule is: Area of bottom on inside -multiplied by the height, equals cubical capacity. For instance, taking -the last tank or cistern in the table: Area of 24 inches (diameter) -is 452.39, which multiplied by 12 inches (height) gives 5427.6 cubic -inches, and this divided by 231 cubic inches in a gallon gives 23 -gallons. - -Supposing the tank to be 24 inches deep instead of 12 inches, the -result would be, of course, twice the number of gallons. - -RULE FOR OBTAINING CONTENTS OF A BARREL IN GALLONS. - -Take diameter at bung, then square it, double it, then add square of -head diameter; multiply this sum by length of cask, and that product -by .2618 which will give volume in cubic inches; this, divided by 231, -will give result in gallons. - - -WATER METERS. - -Water meters, or measurers (apparatus for the measurement of water), -are constructed upon two general principles: 1, an arrangement called -an “_inferential meter_” made to divert a certain proportion of the -water passing in the main pipe and by measuring accurately the small -stream diverted, _to infer_, or estimate the larger quantity; 2, -_the positive meter_; rotary piston meters are of the latter class -and the form usually found in connection with steam plants. They are -constructed on the positive displacement principle, and have only one -working part—a hard rubber rolling piston—rendering it almost, if not -entirely, exempt from liability to derangement. It measures equally -well on all sized openings, whether the pressure be small or great; and -its piston, being perfectly balanced, is almost frictionless in its -operation. - -Constructed of composition (gun-metal) and hard rubber, it is not -liable to corrosion. An ingenious stuffing-box insures at all times a -perfectly dry and legible dial, or the registering mechanism which is -made of a combination of metals especially chosen for durability and -wear, and inclosed in a case of gun-metal. - -[Illustration: Fig. 99.] - -Fig. 99 is a perspective view of the meter, showing the index on the -top. It is shown here as when placed in position. The proper threads -at the inlet and outlet make it easy of attachment to the supply and -discharge pipes. - -The hard rubber piston (the only working part of the Meter) is made -with spindle for moving the lever communicating with the intermediate -gear by which the dial is moved. - -The water, through the continuous movement of the piston, passes -through the meter in an unbroken stream, in the same quantity as with -the pipe to which it is attached when the opening in the meter equals -that of the service pipe; the apparatus is noiseless and practically -without essential wear. - - -“POINTS” RELATING TO WATER METERS. - -In setting a meter in position let it be plumb, and properly secured to -remain so. It should be well protected from frost. - -If used in connection with a steam boiler, or under any other -conditions where it is exposed to a back pressure of steam or hot -water, it must be protected by a check valve, placed between the outlet -of the meter and the vessel it supplies. - -It is absolutely necessary to blow out the supply pipe before setting a -new meter, so that if there be any accumulation of sand, gravel, etc., -in it, the same may be expelled, and thus prevented from entering the -meter. Avoid using red lead in making joints. It is liable to work into -the meter and cause much annoyance by clogging the piston. - -This engraving, Fig. 100, shows the counter of the Meter. It registers -cubic feet—one cubic foot being 7-48/100 U. S. gallons and is read in -the same way as the counters of gas meters. - -[Illustration: Fig. 100.] - -The following example and directions may be of service to those -unacquainted with the method: - -If a pointer be between two figures, the smallest one must always be -taken. When the pointer is so near a figure that it seems to indicate -that figure exactly, look at the dial next below it in number, and if -the pointer there has passed 0, then the count should be read for that -figure. Let it be supposed that the pointers stand as in the above -engraving, they then read 28,187 cubic feet. The figures are omitted -from the dial marked “ONE,” because they represent but tenths of one -cubic foot, and hence are unimportant. From dial marked “10,” we get 7; -from the next marked “100,” we get 8; from the next marked “1,000,” we -get the figure 1; from the next marked “10,000,” the figure 8; from the -next marked “100,000,” the figure 2. - -THE FISH TRAP used in connection with water meters is an apparatus (as -its name denotes) for holding back fishes, etc. - - -THE STEAM BOILER INJECTOR. - -For safety sake, every boiler ought to have two feeds in order to avoid -accidents when one of them gets out of order, and one of these should -be an injector. - -This consists in its most simple form, of a steam nozzle, the end of -which extends somewhat into the second nozzle, called the combining -or suction nozzle; this connects with or rather terminates in a third -nozzle or tube, termed the “forcer.” At the end of the _combining -tube_, and before entering the forcer, is an opening connecting the -interior of the nozzle at this point with the surrounding area. This -area is connected with the outside air by a check valve, opening -outward in the automatic injectors, and by a valve termed the overflow -valve. - -The operation of the injector is based on the fact, first demonstrated -by Gifford, that the motion imparted by a jet of steam to a surrounding -column of water is sufficient to force it into the boiler from which -the steam was taken, and, indeed, into a boiler working at a higher -pressure. The steam escaping from under pressure has, in fact, a much -higher velocity than water would have under the same pressure and -condition. The rate of speed at which steam—taking it at an average -boiler pressure of sixty pounds—travels when discharged into the -atmosphere, is about 1,700 feet per second. When discharged with the -full velocity developed by the boiler pressure through a pipe, say -an inch in diameter, the steam encounters the water in the combining -chamber. It is immediately condensed and its bulk will be reduced say -1,000 times, but its velocity remains practically undiminished. Uniting -with the body of water in the combining tube, it imparts to it a large -share of its speed, and the body of water thus set in motion, operating -against a comparatively small area of boiler pressure, is able to -overcome it and pass into the boiler. The weight of the water to which -steam imparts its velocity gives it a momentum that is greater in the -small area in which its force is exerted than the boiler pressure, -although its force has actually been derived from the boiler pressure -itself. - -The following cut 101 represents the outline of one of the best of a -large number of injectors upon the market, from which the operation of -injectors may be illustrated. - -[Illustration: - - S. Steam jet. V. Suction jet. - R. Ring or auxiliary check. - M. Steam valve and stem, handle. - X. Overflow cap. - C-D. Combining and delivery tube. - P. Overflow valve. O. Steam plug. - N. Packing nut. K. Steam valve - -Fig. 101.] - -The steam enters from above, the flow being regulated by the handle K. -The steam passes through the tube S and expands in the tube V, where it -meets the water coming from the suction pipe. The condensation takes -place in the tubes V and C, and a jet of water is delivered through -the forcer tube D to the boiler. Connection passages are made to the -chamber surrounding the tubes C, D, and to the end of tube V. If the -pressure in this surrounding chamber becomes greater than that of the -atmosphere, the check valve P is lifted and the contents are discharged -through the overflow. - -So long as the pressure in this chamber is atmospheric, the check valve -P remains closed, and all the contents must be discharged through the -tube D. - -There are three distinct types of live steam injectors, the “simple -fixed nozzle,” the “adjustable nozzle,” and the “double.” The first has -one steam and one water nozzle which are fixed in position but are so -proportioned as to yield a good result. There is a steam pressure for -every instrument of this type at which it will give a maximum delivery, -greater than the maximum delivery for any other steam pressure either -higher or lower. The second type has but one set of nozzles, but they -can be so adjusted relative to each other as to produce the best -results throughout a long range of action; that is to say, it so -adjusts itself that its maximum delivery continually increases with the -increase of steam pressure. - -The double injector makes use of two sets of nozzles, the “lifter” and -“forcer.” The lifter draws the water from the reservoir and delivers it -to the forcer, which sends it into the boiler. All double injectors are -fixed nozzle. - -All injectors are similar in their operation. They are designed to -bring a jet of live steam from the boiler in contact with a jet of -water so as to cause it to flow continuously in the direction followed -by the steam, the velocity of which it in part assumes, back into the -boiler and against its own pressure. - -As a thermodynamical machine, the injector is nearly perfect, since -all the heat received by it is returned to the boiler, except such a -very small part as may be lost by radiation; consequently its thermal -efficiency should be in every case nearly 100 per cent. On the other -hand, because of the fact that its heat energy is principally used in -warming up the cold water as it enters the injector, its mechanical -efficiency, or work done in lifting water, compared with the heat -expended, is very low. - -The action of the injector is as follows: Steam being turned on, it -rushes with great velocity through the steam nozzle into and through -the combining tube. This action induces a flow of air from the suction -pipe, which is connected to the combining tube, with the result that a -more or less perfect vacuum is formed, thus inducing a flow of water. -After the water commences to flow to the injector it receives motion -from the jet of steam; it absorbs heat from the steam and finally -condenses it, and thereafter moves on into the forcer tube simply as -a stream of water, at a low velocity compared with that of the steam. -At the beginning of the forcer tube it is subjected only to atmospheric -pressure, but from this point the pressure increases and the water -moves forward at diminished velocity. - - -“POINTS” RELATING TO THE INJECTOR. - -In nine cases out of ten, where the injector fails to do good service, -it will be either because of its improper treatment or location, or -because too much is expected of it. The experience of thoroughly -competent engineers establishes the fact that in almost every instance -in which a reliable boiler feed is required, an injector can be found -to do the work, provided proper care is exercised in its selection. - -The exhaust steam injector is a type different from any of the -above-named, in that it uses the exhaust steam from a non-condensing -engine. Exhaust steam has fourteen and seven-tenths (14.7) pounds of -work, and the steam entering the injector is condensed and the water -forced into the boiler upon the same general principle as in all -injectors. - -The exhaust steam injector would be still more extensively used were it -not for a practical objection which has arisen—it carries over into the -boiler the waste oil of the steam cylinder. - -Some injectors are called by special names by their makers, such as -ejectors and inspirators, but the term injectors is the general name -covering the principle upon which all the devices act. - -The injector can be, and sometimes is, used as a pump to raise water -from one level to another. It has been used as an air compressor, and -also for receiving the exhaust from a steam engine, taking the place in -that case of both condenser and air pump. - -The injector nozzles are tubes, with ends rounded to receive and -deliver the fluids with the least possible loss by friction and eddies. - -Double injectors are those in which the delivery from one injector is -made the supply of a second, and they will handle water at a somewhat -higher temperature than single ones with fixed nozzles. - -The motive force of the injector is found in the heat received from the -steam. The steam is condensed and surrenders its latent heat and some -of its sensible heat. The energy so given up by each pound of steam -amounts to about 900 thermal units, each of which is equivalent to a -mechanical force of 778 foot pounds. This would be sufficient to raise -a great many pounds of water against a very great pressure could it be -so applied, but a large portion of it is used simply to heat the water -raised by the injector. - -The above explanation will apply to every injector in the market, but -ingenious modifications of the principles of construction have been -devised in order to meet a variety of requirements. - -That the condensation of the steam is necessary to complete the process -will be evident, for if the steam were not condensed in the combining -chamber, it would remain a light body and, though moving at high speed, -would have a low degree of energy. - -Certain injectors will not work well when the steam pressure is too -high. In order to work at all the injector must condense the steam -which flows into the combining tube. Therefore, when the steam pressure -is too high, and as a consequence the heat is very great, it is -difficult to secure complete condensation; so that for high pressure -of steam good results can only be obtained with cold water. It would -be well when the feed water is too warm to permit the injector to work -well, to reduce the pressure, and consequently the temperature of the -steam supplied to the injector, as low pressure steam condenses much -easier, and consequently can be employed with better result. Throttling -the steam supplied by means of stop valves will often answer well in -this case. The steam should not be cold or it will not contain heat -units enough to allow it to condense into a cross section small enough -to be driven into the boiler. This is the reason why exhaust injectors -fail to work when the exhaust steam is very cold. It also explains why -such injectors work well when a little live steam is admitted into the -exhaust sufficient to heat it above a temperature of 212°. - -Leaks affect injectors the same as pumps, and in addition, the -accumulation of lime and other mineral deposits in the jets stops the -free flowing of the water. The heat of the steam is the usual cause of -the deposits, and where this is excessive it would be well to discard -the injector and feed with the pump. - -The efficient working of the injector depends materially upon the size -of the jet which should be left as the manufacturer makes it; hence in -repairs and cleaning a scraper or file should not be used. - -For cleaning injectors, where the jets have become scaled, use a -solution of one part muriatic acid to from nine to twelve parts of -water. Allow the tubes to remain in the acid until the scale is -dissolved or is so soft as to wash out readily. - -The lifting attachment, as applied to any injector, is simply a steam -jet pump. It is combined with the injector proper and is operated by -a portion of the steam admitted to the instrument. Nearly all the -successful injectors on the market are made with these attachments, and -will raise water about 25 feet, if required, from a well or tank below -the boiler level. - -Where an injector is required to work at different pressures it must -be so constructed that the space between the receiving tube and the -combining tube can be varied in size. As a rule this is accomplished by -making both combining and receiving tubes conical in form and arranging -the combining tube so that it can be moved to or from the receiving -tube, and the water space thereby enlarged or contracted at will. The -adjustment of the space between the two tubes by hand is a matter of -some difficulty, however; at least it takes more time and patience -than the average engineer has to devote to it, and the majority of the -injectors in use are therefore made automatic in their regulation. - -The injector is not an economical device, but it is simple and -convenient, it occupies but a small amount of space, is not expensive -and is free from severe strains on its durability; moreover, where a -number of boilers are used in one establishment, it is very convenient -to have the feeding arrangements separate, so that each boiler is a -complete generating system in itself and independent of its neighbors. - - - - -LAWS OF HEAT. - - -Heat is a word freely used, yet difficult to define. The word “heat” is -commonly used in two senses: (1) to express the sensation of warmth; -(2) the state of things in bodies which causes that sensation. The -expression herein must be taken in the latter sense. - -Heat is transmitted in three ways—by _conduction_, as when the end of -a short rod of iron is placed in a fire, and the opposite end becomes -warmed—this is conducted heat; by _convection_ (means of currents) such -as the warming of a mass of water in a boiler, furnace, or saucepan; -and by _radiation_, as that diffused from a piece of hot metal or -an open fire. Radiant heat is transmitted, like sound or light, in -straight lines in every direction, and its intensity diminishes -inversely as the square of the distance from its center or point of -radiation. Suppose the distance from the center of radiation to be 1, -2, 3 and 4 yards, the surface covered by heat rays will increase 1, -4, 9 and 16 square feet; the intensity of heat will diminish 1, 1/4, -1/9, and 1/16. and so on in like proportions, until the heat becomes -absorbed, or its source of supply stopped. - -Whenever a difference in temperature exists, either in solids or -liquids that come in contact with or in close proximity to each other, -there is a tendency for the temperature to become equalized; if water -at 100° be poured into a vessel containing an equal quantity of water -at 50°, the tendency will be for the whole to assume a temperature of -75°; and suppose the temperature of the surrounding air be 30°, the -cooling process will continue until the water and the surrounding air -become nearly equal, the temperature of the air being increased in -proportion as that of the water is decreased. - -The heat generated by a fire under the boiler is transmitted to the -water inside the boiler, when the difference in the specific gravities, -or, in other words, the cold water in the pipes being heavier than that -in the boiler sinks and forces the lighter hot water upward. This heat -is radiated from the pipes, which are good conductors of heat to the -air in the room, and raises it to the required temperature. That which -absorbs heat rapidly, and parts with it rapidly, is called a good -conductor, and that which is slow to receive heat, and parts with it -slowly, is termed a bad conductor. - -The following tables of conductivity, and of the radiating properties -of various materials, may be of service: - -CONDUCTING POWER OF VARIOUS SUBSTANCES.—DESPRITZ. - - _Material._ _Conductivity._ - Gold 100 - Silver 97 - Copper 89 - Brass 75 - Cast iron 56 - Wrought iron 37 - Zinc 36 - Tin 30 - Lead 18 - Marble 2.4 - Fire clay 1.1 - Water 0.9 - -RADIATING POWER OF VARIOUS SUBSTANCES.—LESLIE - - _Radiating_ - _Material._ _Power._ - - Lampblack 100 - Water 100 - Writing paper 98 - Glass 90 - Tissue paper 88 - Ice 85 - Wrought lead 45 - Mercury 20 - Polished lead 19 - Polished iron 15 - Gold, silver 12 - Copper, tin 12 - -From the above tables, it will be seen that water, being an excellent -radiator, and of great specific heat, and iron a good conductor, these -qualities, together with the small cost of the materials, combine to -render them efficient, economic and convenient for the transmission and -distribution of artificial heat. - -By adopting certain standards we are enabled to define, compare and -calculate so as to arrive at definite results, hence the adoption of a -standard unit of heat, unit of power, unit of work, etc. - -The standard unit of heat is the amount necessary to raise the -temperature of one pound of water at 32° Fahr. one degree, _i.e._, from -32° to 33°. - -Specific heat is the amount of heat necessary to raise the temperature -of a solid or liquid body a certain number of degrees; water is adopted -as the unit or standard of comparison. The heat necessary to raise one -pound of water one degree, will raise one pound of mercury about 30 -degrees, and one pound of lead about 32 degrees. - - -TABLE OF THE SPECIFIC HEAT OF EQUAL WEIGHTS OF VARIOUS SUBSTANCES. - - _Specific_ - _Solid bodies._ _Heat._ - Wood (fir and pine) 0.650 - „ (oak) 0.570 - Ice 0.504 - Coal 0.280 - Charcoal (animal) 0.260 - „ (vegetable) 0.241 - Iron (cast) 0.241 - Coke 0.201 - Limestone 0.200 - Glass 0.195 - Steel (hard) 0.117 - „ (soft) 0.116 - Iron (wrought) 0.111 - Zinc 0.095 - Copper (annealed) 0.094 - „ (cold hammered) 0.093 - Tin 0.056 - Lead 0.031 - _Liquids._ - Water 1.000 - Alcohol 0.158 - Acid (pyroligneous) 0.590 - Ether 0.520 - Acid (acetic) 0.509 - Oil (olive) 0.309 - Mercury 0.033 - - _Gases._ - Hydrogen 3.409 - Vapor of alcohol 0.547 - Steam 0.480 - Carbonic oxide 0.245 - Nitrogen 0.243 - Oxygen 0.217 - Atmospheric air 0.237 - Carbonic acid 0.202 - - - - -THE STEAM PUMP. - - -It is difficult to overestimate the importance, in connection with a -steam plant, of the appliance which supplies water for the boiler, not -only, but a hundred other uses. Upon the steady operation of the pump -depends the safety and comfort of the engineer, owner and employee, and -indirectly of the success of the business with which the “plant” is -connected. Hence the necessity of acquiring complete knowledge of the -operation of a device so important. - -[Illustration: Fig. 102.] - -Pumps now raise, convey and deliver water, beer, molasses, acids, -oils, melted lead. Pumps also handle, among the gases, air, ammonia, -lighting gas, and oxygen. Pumps are also used to increase or decrease -the pressure of a fluid. - -Pumps are made in many ways, and defined as rope, chain, diaphragm, -jet, centrifugal, rotary, oscillating, cylinder. - -Cylinder pumps are of two classes, single acting and double acting. -In single acting—in effect is _single ended_—in double acting, the -motion of the cylinder in one direction causes an inflow of water and -a discharge at the same time, in the other; and on the return stroke -the action is renewed as the discharge end becomes the suction end. The -pump is thus double acting. - -A _direct pressure_ steam pump is one in which the liquid is pressed -out by the action of steam upon its surface, without the intervention -of a piston. A direct acting steam pump is an engine and pump combined. - -A cylinder or reciprocating pump is one in which the piston or plunger, -in one direction, causes a partial vacuum, to fill which the water -rushes in pressed by the air on its head. - -NOTE.—A _suction valve_ prevents the return of this water on the return -stroke of the piston, and a _discharge valve_ permits the outward -passage of the fluid from the pump but not its return thereto or to the -reservoir through the suction pipe. - -The force against which the pump works is gravity or the attraction of -the earth which prevents the water from being lifted. This is shown -by the fact that water can be led, or trailed, an immense distance, -limited only by the friction, by a pump. - -NOTE.—It may be noted that the difference between a fluid and _liquid_ -is shown in the fact that the latter can be poured from one vessel to -another, thus: air and water are both fluids, but of the two water -alone is liquid: air, ammonia, etc., are _gases_, while they are also -fluids, _i.e._, they flow. - -The idea entertained by many that water is raised by suction, is -erroneous. Water or other liquids are raised through a tube or hose by -the pressure of the atmosphere on their surface. When the atmosphere is -removed from the tube there will be no resistance to prevent the water -from rising, as the water outside the pipe, still having the pressure -of the atmosphere upon its surface, forces water up into the pipe, -supplying the place of the excluded air, while the water inside the -pipe will rise above the level of that outside of it proportionally to -the extent to which it is relieved of the pressure of the air. - -If the first stroke of a pump reduces the pressure of the air in the -pipe from 15 pounds on the square inch to 14 pounds, the water will be -forced up the pipe to the distance of 2-1/4 feet, since a column of -water an inch square and 2-1/4 feet high is equal in weight to about -1 pound. Now if the second stroke of the pump reduces the pressure of -the atmosphere in the pipe to 13 pounds per inch, the water will rise -another 2-1/4 feet; this rule is uniform, and shows that the rise of -the column of water within the pipe is equal in weight to the pressure -of the air upon the surface of the water without. - -There are pumps (Centrifugal) especially designed for pumping water -mingled with mud, sand, gravel, shells, stones, coal, etc., but with -these the engineer has but little to do, as they are used mostly for -wrecking and drainage. - -The variety of pattern in which pumps are manufactured and the still -greater variation in capacity forbids an attempt to fully illustrate -and describe further than their general principles, and to name the -following general - - -CLASSIFICATION OF PUMPS. - -1st. Pumps are divided into Vertical and Horizontal. - -Vertical pumps are again divided into: - - 1. Ordinary Suction or Bucket Pumps. - 2. Suction and Lift Pumps. - 3. Plunger or Force Pumps. - 4. Bucket and Plunger Pumps. - 5. Piston and Plunger Pumps. - -Horizontal Pumps are divided into: - - 1. Double-acting Piston Pumps. - 2. Single-acting Plunger Pumps. - 3. Double-acting Plunger Pumps. - 4. Bucket and Plunger Pumps. - 5. Piston and Plunger Pumps. - -[Illustration: Fig. 103. - - A—Air Chamber. - B—Water Cylinder Cap. - C—Water Cylinder with Valves and Seats in. - D—Rocker Shafts, each, Long or Short. - E—Removable Cylinders, each. - F—Water Piston and Follower, each. - „—Water Piston Followers, each. - G—Rocker Stand. - H—Suction Flange, threaded. - I—Discharge Flange, threaded. - J—Intermediate Flanges, each. - K—Water Cylinder Heads, each. - L—Concaves complete, with Stuffing Boxes, each. - M—Steam Cylinder, without Head, Bonnet and Valve. - N—Steam Cylinder Foot. - O—Crosshead Links, each. - P—Steam Piston complete with Rings and Follower, each. - m—Steam Piston Head. - n—Steam Piston Follower. - Steam Piston Rings, including Spring and Breakjoint. - Q—Side Water Cylinder Bonnet, each. - R—Steam Chest Bonnet, each. - S—Steam Chest Stuffing Box Gland, each. - T—Steam Slide Valve, each. - U—Piston Rods, each. - V—Crossheads, each. - W—Rocker Arms, each, Long or Short. - X—Valve Rod Links, each, Long or Short. - Y—Steam Valve Stems, each. - Z—Steam Cylinder Heads, each. - aa—Piston Rod Nuts, each. - hh—Piston Rod Stuffing Glands, each. - ii—Water Valve Seats, each. - jj—Rubber Valves, each. - kk—Water Valve Stems, each. - ll—Water Valve Springs, each. - gg—Removable Cylinder Screws, each. - b—Steam Valve Stem Forks, each. - c—Steam Valve Stem Fork Bolts, each. - e—Valve Rod Link Bolts, each. - d—Rocker Arm Pins, each. - f—Crosshead Link Bolts, each. - o—Collar Bolts, each. - pp—Brass Steam Cylinder Drain Cocks, each. - Water Packings, each. - Brass Piston Rods, each. - Brass Lined Removable Cylinders, extra, each. - Piston Rod Stuffing Gland Bolts, each. - Water Cylinder Cap Bonnets, each. - Top Valve Caps, each. - Valve Cap Clamps, each. -] - -In Figs. 102 and 103 are exhibited the outlines of _the double acting -steam pump_, which is undoubtedly the pattern most thoroughly adapted -for feeding steam boilers, as it is equipped for the slowest motion -with less risk of stopping on a centre. - -From the drawing with reference letters may be learned the terms -applied generally to the parts of all steam pumps: example: “k” shows -the water valve stems, “K” the water cylinder heads. - -It may be remarked that nearly all pump makers furnish valuable printed -matter, giving directions _as to repairs_, and best method of using -their particular pumps—especially valuable are their repair sheets in -which are given cuts of “parts” of the pumps. It were well for the -steam user and engineer to request such matter from the manufacturers -for the special pump they use. - - -POINTS RELATING TO PUMPS. - -Blow out the steam pipe thoroughly with steam before connecting it to -the engine; otherwise any dirt or rubbish there might be in the pipe -will be carried into the steam cylinder, and cut the valves and piston. - -Never change the valve movement of the engine end of the pump. If any -of the working parts become loose, bent or broken, replace them or -insert new ones, in precisely the same position as before. - -Keep the stuffing boxes nearly full of good packing well oiled, and set -just tight enough to prevent leakage without excessive friction. - -Use good oil only, and oil the steam end just before stopping the pump. - -It is absolutely necessary to have a full supply of water to the pump. - -If possible avoid the use of valves and elbows in the suction pipe, and -see that it is as straight as possible; for bends, valves and elbows -materially increase the friction of the water flowing into the pump. - -See that the suction pipe is not imbedded in sand or mud, but is free -and unobstructed. - -All the pipes leading from the source of supply to the pump must be -air-tight, for a very small air-leak will destroy the vacuum, the pump -will not fill properly; its motion will be jerky and unsteady, and the -engine will be liable to breakage. - -A suction air chamber (made of a short nipple, a tee, a piece of pipe -of a diameter not less than the suction pipe and from two to three feet -long, and a cap, screwed upright into the suction pipe close to the -pump) is always useful; and where the suction pipe is long, in high -lifts, or when the pump is running at high speed, it is a positive -necessity. - -Never take a pump apart before using it. If at any time subsequently -the pump should act badly, always examine the pump end first. And if -there is any obstruction in the valve, remove it. See that the pump is -well packed, and that there are no cracks in pipes or pump, nor any -air-leaks. - -In selecting a pump for boiler feeding it is well to have it plenty -large enough, and also these other desirable features: few parts, have -no dead points or center, be quiet in operation, economical of steam -and repairs, and positive under any pressure. - -Granted motion to the piston or plunger, a pump fails because it -leaks. There can be no other reason, and the leak should be found and -repaired. Leaky valves are common and should be ground. Leaky pistons -are not so common, but sometimes occur. Repairing is the remedy. Leaky -plungers are common. They need re-turning. The rod must be straight as -far as in contact with the packing. The packing around the plungers is -sometimes neglected too long, gets filled with dirt and sediment, and -hardens and scores an otherwise perfect rod, and so leaks. - -The lifting capacity of a pump depends upon proper proportion of -clearance in the cylinder and valve chamber, to displacement of the -piston and plunger. - -An injector is a sample of a _jet pump_—this may either lift or force -or both. - -The most necessary condition to the satisfactory working of the steam -pump is a full and steady supply of water. The pipe connections should -in no case be smaller than the openings in the pump. The suction lift -and delivery pipes should be as straight and smooth on the inside as -possible. - -When the lift is high, or the suction long, a foot valve should be -placed on the end of the suction pipe, and the area of the foot valve -should exceed the area of the pipe. - -The area of the steam and exhaust pipes should in all cases be fully as -large as the nipples in the pump to which they are attached. - -The distance that a pump will lift or draw water, as it is termed, -is about 33 feet, because water of one inch area 33 feet weighs 14.7 -pounds; but pumps must be in good order to lift 33 feet, and all pipes -must be air-tight. Pumps will give better satisfaction lifting from 22 -to 25 feet. - -In cold weather open all the cocks and drain plugs to prevent freezing -when the pump is not in use. - -When purchasing a steam pump to supply a steam boiler, one should be -selected capable of delivering one cubic foot of water per horse-power -per hour. - -No pump, however good, will lift hot water, because as soon as the air -is expelled from the barrel of the pump the vapor occupies the space, -destroys the vacuum, and interferes with the supply of water. As a -result of all this the pump knocks. When it becomes necessary to pump -hot water, the pump should be placed below the supply, so that the -water may flow into the valve chamber. - -The air vessel on the delivery pipe of the steam pump should never be -less than five times the area of the water cylinder. - -There are many things to be considered in locating steam pumps, such as -the source from which water is obtained, the point of delivery, and the -quantity required in a given time; whether the water is to be lifted or -flows to the pump; whether it is to be forced directly into the boiler, -or raised into a tank 25, 50 or 100 feet above the pump. - -The suction chamber is used to prevent pounding when the pump reverses -and to enable the pump barrel to fill when the speed is high. - -Suction is the unbalanced pressure of the air which is at sea level -14-7/10 per inch, or 2096.8 per square foot. - -When a valve is spoken of in connection with a pump it may be -understood that there may be several valves dividing and performing the -functions of one. - -A simple method of obtaining tight pump-valves consists simply in -grooving the valve-sheets and inserting a rubber cord in the grooves. -As the valves seat themselves the cord is compressed and forms a tight -joint. An additional advantage is that it prevents the shock ordinarily -produced by rapid closing and prolongs the life of the valve seat. The -rubber cord when worn can be easily and quickly replaced. - - -CALCULATIONS RELATING TO PUMPS. - -_To find the pressure in pounds per square inch_ of a column of water, -multiply the height of the column in feet by .434, Approximately, we -say that every foot elevation is equal to 1/2 lb. pressure per square -inch; this allows for ordinary friction. - -_To find the diameter of a pump cylinder_ to move a given quantity of -water per minute (100 feet of piston being the standard of speed), -divide the number of gallons by 4, then extract the square root, and -the product will be the diameter in inches of the pump cylinder. - -_To find quantity of water_ elevated in one minute running at 100 feet -of piston speed per minute. Square the diameter of the water cylinder -in inches and multiply by 4. Example: capacity of a 5 inch cylinder is -desired. The square of the diameter (5 inches) is 25, which, multiplied -by 4, gives 100, the number of gallons per minute (approximately). - -_To find the horse power_ necessary to elevate water to a given height, -multiply the weight of the water elevated per minute in lbs. by the -height in feet, and divide the product by 33,000 (an allowance should -be added for water friction, and a further allowance for loss in steam -cylinder, say from 20 to 30 per cent.). - -_The area of the steam piston_, multiplied by the steam pressure, gives -the total amount of pressure that can be exerted. _The area of the -water piston_, multiplied by the pressure of water per square inch, -gives the resistance. _A margin_ must be made between the _power_ and -the _resistance_ to _move_ the piston at the required speed—say from 20 -to 40 per cent., according to speed and other conditions. - -_To find the capacity of a cylinder_ in gallons. Multiplying the area -in inches by the length of stroke in inches will give the total number -of cubic inches; divide this amount by 231 (which is the cubical -contents of a U. S. gallon in inches), and product is the capacity in -gallons. - -The temperature 62° F. is the temperature of water used in calculating -the specific gravity of bodies, with respect to the gravity or density -of water as a basis, or as unity. - -[Illustration: Fig. 104.] - -Important stress has been laid upon keeping all floating objects, -gravel, etc., away from the acting parts of the pump. In Fig. 104 is -presented a cut of an approved strainer which can be removed, freed -from obstruction, and replaced by simply slacking one bolt, the entire -operation occupying one minute. The advantages of this strainer will be -readily apparent. - - - - -IMPORTANT PRINCIPLES RELATING TO WATER. - - -There are some underlying natural laws and other data relating to water -which every engineer should thoroughly understand. Heat, _water_, -steam, are the three properties with which he has first to deal. - -_Weight of one cubic foot of Pure Water._ - - At 32° F. = 62.418 pounds. - At 39.1°F = 62.425 „ - At 62° (Standard temperature) = 62.355 „ - At 212° = 59.640 „ - -The weight of a cubic foot of water is about 1000 ounces (exactly 998.8 -ounces), at the temperature of maximum density. - -The weight of a cylindrical foot of water at 62° F. is 49 lbs. -(nearly). The weight of a cylindrical inch is 0.4533 oz. - -There are four notable temperatures for water, namely, - - 32° F., or 0° C. = the freezing point under one atmosphere. - 39.1° or 4° = the point of maximum density. - 62° or 16°.66 = the standard temperature. - 212° or 100° = the boiling point, under one atmosphere. - -_Water rises to the same level in the opposite arms of a recurved -tube_, hence water will rise in pipes as high as its source. - -_The pressure on any particle of water is proportioned to its depth -below the surface_, and as the side pressure is equal to the downward -pressure. - -_Water at rest presses equally in all directions._ This is a most -remarkable property, the upward direction of the pressure of water is -equal to that pressing downwards, and the side pressure is also equal. - -_Any quantity of water, however small, may be made to balance any -quantity, however great._ This is called the Hydrostatic Paradox, and -is sometimes exemplified by pouring liquids into casks through long -tubes inserted in the bung holes. As soon as the cask is full and -the water rises in the pipe to a certain height the cask bursts with -violence. - -_Water is practically non-elastic._ A pressure has been applied of -30,000 pounds to the square inch and the contraction has been found to -be less than one-twelfth. - -_The surface of water at rest is horizontal._ A familiar example of -this may be noted in the fact that the water in a battery of boilers -seeks a uniform level, no matter how much the cylinders may vary in -size. - -_A given pressure or blow impressed on any portion of a mass of water -confined in a vessel is distributed equally through all parts of the -mass_; for example a plug forced inwards on a square inch of the -surface of water, is suddenly communicated to every square inch of the -vessel’s surface, however large, and to every inch of the surface of -any body immersed in it. - - -WEIGHT AND CAPACITY OF DIFFERENT STANDARD GALLONS OF WATER. - - +-------------+------------+------------+------------+------------+ - | |Cubic inches|Weight of a |Gallons in a|Weight of a | - | |in a Gallon.| Gallon in | cubic foot.| cubic foot | - | | | pounds. | | of water, | - +-------------+------------+------------+------------+ English | - |Imperial or | | | | standard, | - | English | 277.264 | 10.00 | 6.232102 |62.221 lbs. | - |United States| 231. | 8.33111 | 7.480519 |Avoirdupois.| - +-------------+------------+------------+------------+------------+ - - - - -STORING AND HANDLING OF COAL. - - -The best method of storing coal is a matter of economy and needs the -attention of the engineer. - -Coal, as it comes from the mine, is in the best possible condition for -burning in a furnace; its fracture is bright and clean, and it ought -to be preserved up to the time of using it in such manner as to avoid -as much as possible any alteration of its condition so as to prevent -deterioration. - -So far as actual experience goes it has been found that a brick -building, with double walls to promote coolness, with high narrow slits -instead of windows, with ventilating holes along the bottom of the -walls, having a high-pitched roof with overhanging eaves, and holes for -ventilation well sheltered under the eaves, and with ventilators along -the edge of the roof, is best suited to keep the coal in the condition -most nearly approaching that of the freshly mined. The floor of the -building should be preferably paved with brick on edge or flagstones; -the doors should be large and kept open in damp weather, and closed -when the weather is hot. - -Some persons recommend sprinkling the coal occasionally during the hot -weather, but it is much better to wet down the paving all around the -building outside, and the exposed floor of the building, as well as the -walls inside and outside, and let the moisture of the evaporation have -its effect upon the coal. It will be found to be amply sufficient for -the purpose. - -It has been found long since that it is better to have coal sheds dark, -as light assists greatly in impairing the fuel. - -The best arrangement for a boiler room floor is to have a coal-bin, -paved with stone flags, opening into the fire-room by a door, while the -fire-room itself should be paved diagonally with brick, set on edge -upon a concrete foundation, well rammed to within about three feet of -the boiler front, and the remaining space should be floored with iron -plates. - -The coal should be wheeled from the bins and dumped upon these plates, -never on the brick floor. These plates should be laid on an incline -of about an inch toward the boilers, and it is well to have a trough -or gutter, of about six inches in width, and having a depth of about -one and a half inches cast in them, at the edge lying nearest the -boilers, so that the water from the gauge-cock, drip-pipes, and that -from wetting down the ashes may run into it and drain into a proper -sewer-pipe laid under the flooring. - - - - -CHEMISTRY OF THE FURNACE. - - -A careful estimate by a Broadway Chemist of the contents or -constituents of a ton of coal presents some interesting facts, not -familiar certainly to unscientific minds. It is found that, besides -gas, a ton of ordinary gas coal will yield 3,500 pounds of coke, twenty -gallons of ammonia water and 140 pounds of coal tar. Now, destructive -distillation of this amount of coal tar gives about seventy pounds of -pitch, seventeen pounds of creosote, fourteen pounds of heavy oils, -about nine and a half pounds of naphtha yellow, six and one-third -pounds of naphthaline, four and three-fourth pounds of alizarine, -two and a fourth pounds of solvent naphtha, one and a fifth pound of -aniline, seventy-nine hundredths of a pound of toludine, forty-six -hundredths of a pound of anthracine, and nine-tenths of a pound of -toluches—from the last-named substance being obtained the new product, -saccharine, said to be 230 times as sweet as the best cane sugar. - -From an engineer’s standpoint the main constituents of all coal are -carbon and hydrogen; in the natural state of coal these two are -united and solid; their respective characters and modes of entering -into combustion, are however essentially different. The hydrogen is -convertable into heat only in the gaseous state; the carbon, on the -contrary, is combustible only in the solid condition. It must be borne -in mind that neither is combustible while they are united. - -There are, however, other elements existing in coal in its natural -state, and new ones are formed during burning or combustion as will be -noted in the succeeding paragraphs. - -For raising steam the process of combustion consists in disentangling, -letting loose or evolving the different elements locked up in coal; the -power employed in accomplishing this is _heat_. The chemical results of -this consumption of the fuels may be divided into four stages or parts. - -First stage, application of existing heat to disengage the constituent -gases of the fuel. In coals this is principally mixed carbon and -hydrogen. - -Second stage, application or employment of existing heat to separate -the carbon from the hydrogen. - -Third stage, further employment of existing heat to increase the -temperature of the two combustibles, carbon and hydrogen, until they -reach the heat necessary for combination with the air. If this heat is -not obtained, chemical union does not take place and the combustion is -imperfect. - -Fourth and last stage, the union of the oxygen of the air with the -carbon and hydrogen of the furnace in their proper proportions, -when intense heat is generated and light is also given off from the -ignited carbon. The temperature of the products of combustion at this -final stage depend upon the quantity of air in dilution. Sir H. Davy -estimates this heat as greater than the white heat of metals. - -In the first stages heat is absorbed, but is given out in the last. -When the chemical atoms of heat are not united in their proper -proportions, then carbonic oxide, mixed carbon and hydrogen, and other -combustible gases escape invisibly, with a corresponding loss of heat -from the fuel. - -When the proper union takes place, then only steam, carbonic acid and -nitrogen, all of which are incombustible, escape. - -The principal products, therefore, of perfect combustion are: steam, -invisible and incombustible; carbonic acid, invisible and incombustible. - -The products of imperfect combustion are: carbonic oxide, invisible but -combustible; smoke, partly invisible and partly incombustible. - -Steam is formed from the hydrogen gas given out by the coals combining -with its equivalent of oxygen from the air. Smoke is formed from -the hydrogen and carbon which have not received their respective -equivalents of oxygen from the air, and thus pass off unconsumed. The -color of the smoke depends upon the carbon passing off in its dark, -powdery state. - -The heat lost is not dependent upon the amount of carbon alone, but -also upon the invisible but combustible gases, hydrogen and carbonic -oxide; so that while the color may indicate the amount of carbon in the -smoke, it does not indicate the amount of the heat lost; hence, the -smokeless locomotive burning coke may lose more heat in this way than -that arising from the imperfect burning of coal under the stationary -engine boiler. - -A practical and familiar instance of imperfect combustion is exhibited -when a lamp smokes and the unconsumed carbon is deposited all about in -the form of soot. When the evolving or disengagement of the carbon is -reduced by lowering the wick to meet the supply of oxygen, the carbon -is all consumed and the smoke ceases. What takes place in a lamp also -occurs in a furnace, so that the proper supply of air is a primary -thing, relating to economy, both as regards its quantity and its mode -of admission to a fire. - -The economical generation of heat is one thing, the use made of -that heat afterwards is another. Combustion may be perfect, but the -absorption of heat by a boiler may be inferior. - -The chief agents operating in the furnace are carbon, hydrogen and -oxygen, and their union in certain proportions produces other bodies, -as water or steam, carbonic acid, besides others of less practical -importance. - - -OXYGEN is an invisible gas, has no smell, and remains permanently in -receptacles, unchanged by time. It can be obtained in an experimental -quantity by heating the chlorate of potash, and collecting the gas -given off in a bladder or jar. It is a trifle heavier than common -air, _i.e._, 1.106 times and a cubic foot at 32° temperature weighs -1.428 ounces. It is one of the most abundant bodies in nature, and is -combined with many others in a great variety of ways. - - -CARBON is one of the most interesting elementary substances in -nature. It is combustible and forms the base of charcoal, and enters -largely into mineral coal. It is a mineral capable of being reduced to -a feathery powder, and is found in many different forms. It is obtained -by various processes: from oil lamps as lamp-black; from coal as coke, -and from wood as charcoal; the mineral particles of carbon in a state -of combustion render flame luminous from either gas, oil or candles. - -Carbon unites with iron to form steel, and with hydrogen to form the -common street gas. Carbon is considered as the next most abundant body -in nature to oxygen. In the furnace the carbon of the fuel unites -with the oxygen of the air to produce heat; if the supply of air is -correctly regulated, there will be perfect combustion, but if the -supply of air be deficient, combustion will be imperfect. - - -HYDROGEN is an invisible gas, and the lightest known body in the world, -being many times lighter than oxygen. It is combustible and gives out -much heat. In our gas establishments it is made in large quantities and -combined with carbon for illuminating streets, shops and dwellings. It -is the source of all common flame. When united with sulphur in coal -mines it becomes explosive. By passing a current of steam through a hot -iron tube partly filled with filings, hydrogen gas is given off and -burns with a pale yellow flame. - -The more hydrogen, therefore, there is in the fuel, the greater in -general is its heating power. But it must be borne in mind that the -element of hydrogen is, nevertheless, to a greater or less degree -neutralized by the other element, oxygen, when it is present as a -constituent of the fuel; since the affinity of hydrogen for oxygen is -superior to that of carbon, and the oxygen saturated with hydrogen is -converted into steam and rises in this form from the fuel bed without -producing heat. Thus it is that the more oxygen there is in the fuel -the less is its power for developing heat by combustion. - - -NITROGEN is also an elementary body. It neither supports life nor -combustion; it is lighter than air and has no taste or smell. One cubic -foot at 32° temperature weighs a trifle less than one ounce. - - -SULPHUR is also an elementary body, of a yellow color, brittle, does -not dissolve in water, is easily melted, and inflammable. It is also -called brimstone or _burnstone_, from its great combustibility. It -burns with a blue flame, and with a peculiar, suffocating odor. - - -CARBONIC ACID GAS is formed by the burning of sixteen parts of oxygen -and six parts of carbon. Its specific gravity is 1.529; it is fatal to -life, and it also extinguishes fire. - - -CARBONIC OXIDE is a colorless, transparent, combustible gas, which -burns with a pale blue flame, as may be seen at times on opening a -locomotive fire-box door. Its presence in a furnace is evidence of -imperfect combustion from a deficient supply of air, as it indicates -that only eight parts of oxygen instead of sixteen parts have united -with six parts of carbon. - - -TABLE. - -The following table exhibits the comparative amounts of water which can -be, under perfect conditions, evaporated from the substances named: - - One pound burned. Water evaporated. - Hydrogen 64.28 - Carbon (average of several experiments) 14.77 - Carbonic Oxide 4.48 - Sulphur 4.18 - Alcohol 13.40 - Oil gas 22.11 - Turpentine 20.26 - -The last four substances are compounds, and the last three consist -almost wholly, or chiefly of carbon and hydrogen. The total heating -power of average coal is, it may be noted to advantage, about 12.83 -pounds of water upon the same conditions as above described. Hydrogen, -it is seen, stands pre-eminently at the head of the list for heating -power, represented by the evaporation of 64-1/4 pounds of water, whilst -carbon, the next in order, and the staple combustible element in fuel, -has only a heating power of 14-3/4 pounds of water. - - - - -HEAT-PROOF AND ORNAMENTAL PAINTS. - - -Steam pipes, boiler fronts, smoke connections and iron chimneys are -often so highly heated that the paint upon them burns, changes color, -blisters and often flakes off. After long protracted use under varying -circumstances, it has been found that a silica-graphite paint is well -adapted to overcome these evils. Nothing but _boiled linseed oil_ is -required to thin the paint to the desired consistency for application, -no dryer being necessary. The paint is applied in the usual manner with -an ordinary brush. The color, of course, is black. - -Another paint, which admits of some variety in color, is made by mixing -soapstone, in a state of fine powder, with a quick-drying varnish -of great tenacity and hardness. This will give the painted object -a seemingly-enameled surface, which is durable and not affected by -heat, acids, or the action of the atmosphere. When applied to wood it -prevents rotting, and it arrests disintegration when applied to stone. -It is well known that the inside of an iron ship is much more severely -affected by corrosion than the outside, _and this paint has proven -itself to be a most efficient protection from inside corrosion_. It is -light, of fine grain, can be tinted with suitable pigments, spreads -easily, and takes hold of the fibre of the iron or steel quickly and -tenaciously. - -Turpentine well mixed with black varnish also makes a good coating for -iron smoke pipes. - -Much brighter and more pleasant appearing engine rooms can be made by -making the surfaces white. Lime is a good non-conductor of heat, and -it has the further quality of protecting iron from rust, so it would -appear that whitewash was as good a material with which to cover boiler -fronts, smoke stacks, steam pipes, etc., as any other substance. - -To prepare whitewash for this purpose it is only necessary to add a -little salt or glue to the water used for dissolving the lime, as -either of these substances will make it stick readily and it cannot -afterward be easily rubbed off; but perhaps the best way to prepare -the whitewash would be to boil a pound of rice until it has become the -consistency of starch, all of the solid particles having been broken up -by boiling, and add this solution to the solution of lime in water. - -This last preparation is also very good for outside work, for after it -has been applied and has an opportunity to dry, no amount of rain will -wash it off and its appearance is almost equal to white paint, and no -amount of heat ordinarily met with will discolor it, although the heat -of the fire box doors, if it was applied in such place, would give it a -brownish cast of color. Even the brick setting of a boiler looks very -much better when nicely whitewashed than when of its natural color, -and if the ceiling and walls of the boiler room are also whitewashed -the effect is quite pleasing, more healthful and conduces greatly to -cleanliness. - -Any engineer who tries this, renewing the whitewash as frequently as he -would paint, will give this plan of painting pipes and boiler front the -preference over the use of any kind of black paint. - - - - -PRESSURE RECORDING GAUGE. - - -This device is an ingenious mechanism actuated by clock work and the -varying pressures of steam formed within the boiler; it records the -time and the pressure upon a revolving roll of paper and preserves an -accurate account of the varying conditions which have existed within -the boiler. - -[Illustration: Fig. 105.] - -The advantages derived from its use may be thus summarized: 1, It is a -monitor constantly teaching the fireman to be careful to maintain an -equal pressure of steam. 2, This uniform steam made possible by the use -of the gauge is productive of the greatest possible economy. 3, The -even strain maintained insures a long life to the boiler and a minimum -of repairs. 4, It is the vindication of an attentive and careful -fireman and allows him due credit for his skill and faithfulness, which -is too often ill appreciated for lack of a reliable record. - -Although described as a boiler room fixture, where it is frequently -found in position, the proper place for this admirable device is in -the steam user’s office, thus establishing _a nerve connection_, -between engineer and owner, relating to the safety and economy of the -power-plant to their mutual great advantage. - - - - -HORSE POWER AS APPLIED TO BOILERS. - - -By general agreement a horse power as applied to steam boilers is -thirty (30) pounds of feed water at a temperature of 100 degrees Fahr. -converted into steam in 1 hour at 70 pounds gauge pressure. - -The standard is all that can be asked because the same test will -determine two things; first the steam making capacity of the boiler and -second its evaporative efficiency, which is all that is necessary to -know in determining the commercial rating of boilers. - -But it is a fact that, without an engine attached, there is no -such thing as calculating the horse power of a boiler upon general -principles. A well constructed engine with a given pressure of steam -upon a piston of a given area and moving at a certain velocity in feet -per minute, will always and under all conditions develop the same power -so long as the boiler is able to furnish a sufficient quantity of steam -to keep up that pressure; and it matters not whether the steam is taken -from a boiler rated at 60 horse power or 30. - -An evidence of the fact that there is no standard rule for calculating -the horse power of boilers that can be depended upon, is that no two -engine builders send out the same sized boilers with the engine of the -same rated power. Experience has taught them that to furnish steam -sufficient to work their engines up to their ratings that a certain -sized boiler is required, and what would be considered 30 horse power -by one manufacturer might be considered 35 or more by another—the -difference being in the economy of the engine of using the steam, and -not in the boiler for making it. - -Then, again, a boiler that might furnish a sufficient quantity of steam -to work a certain type of engine up to 40 horse power without forcing -the fire might, with another style of engine, in order to generate -the same power and perform the same duty, require to be forced beyond -the limits of safety or economy. Therefore, considering the varying -conditions under which all steam boilers are placed, there is no such a -thing as any reliable standard rule for calculating the horse power of -boilers, but only an approximate one at the best. - -Hence it is best to select an engine of a certain power, and then let -the same manufacturers furnish a boiler to correspond with it; and so -long as the two are adapted to each other and the boiler of sufficient -capacity to work the engine up to its full ratings, it matters but -little whether the boiler figures the same horse power or not. - -It has been found in practice that it is not good economy to carry -pressure higher than eighty pounds in single cylinder automatic cut off -engines. - -As pressures increase, it becomes possible to use more economical -engines, reducing water consumption per horse power per hour, thus -requiring a smaller amount of heating surface and grate surface, that -is to say, a smaller boiler and furnace for a given power. - -For pressure between eighty and one hundred and twenty pounds, the -compound engine gives the best results, while for higher pressures -triple and quadruple expansion engines are the most economical. - - -RULE FOR ESTIMATING HORSE POWER OF HORIZONTAL TUBULAR STEAM BOILERS. - -Find the square feet of _heating surface_ in the shell, heads and -tubes, and divide by 15 for the nominal horse power. - -The office of a boiler is to make steam and its real efficiency or the -measure of its utility to the purchaser is measured by the amount of -water it can turn into steam in a certain length of time and the amount -of coal it requires to do this work. - -An ordinary 54″×16′ boiler with forty 4″ tubes, 25 sq. ft. of grate -surface and 800 sq. ft. of heating surface, in a general way is a 75 h. -p. boiler, but good practice will get from it 100 h. p., and the very -best modern engines 200 h. p. - - - - -BOILER SETTING. - - -The method, either ill or good in which steam boilers are “set” or -arranged in their brick work and connections, will vary the quantity of -fuel used by as much as one-fifth; hence the importance of knowing the -correct principles upon which the work should be done. - -[Illustration: Fig. 106.] - -The portion of the steam plant called “the boiler” is composed of two -parts—the boiler and _the furnace_, and the latter may be considered a -part of the “setting” as it is mainly composed of brick work. - -Two kinds of brick are used in boiler setting—the common brick -for walls, foundations and backing to the furnace, and so-called -fire-brick, which should be laid at every point where the fire operates -directly upon the furnace and passages. - -Fire brick should be used in all parts of the setting which are exposed -to the hot gases. It is better to have fire brick lining tied in with -red brickwork, unless the lining is made 13-1/2 inches thick, when it -can be built up separate from outside walls. This arrangement will -require very heavy walls. As usual, but 9 inches fire brick lining is -used in the fireplace and 4-1/2 inches behind the bridge wall. Joints -in the fire brick-work should be as thin as possible. - -Fig. 106 represents some of the different shapes in which fire brick -are made to fit the side of the furnace. They are called by special -names indicated by their peculiar form, circle-brick, angle-brick, -jamb-brick, arch-brick, etc. The common fire brick are 9″×4-1/2″×2-1/2″ -in size, as shown in the figure. - -The peculiar quality in fire bricks is their power to resist for a long -time the highest temperatures without fusion; they should be capable of -being subjected to sudden changes of temperature without injury, and -they should be able to resist the action of melted copper or iron slag. -Fire brick are cemented together with fire clay which is quite unlike -the ordinary mortar which is most suitable for common brick. - -The setting as well as construction of boilers differs greatly, but in -all the end to be sought for is _a high furnace heat_, with as little -_waste as possible, at the chimney end_. To attain this there must -be (1) a sufficient thickness of wall around the furnace, including -the bridge, to retain as nearly as may be every unit of heat. (2) A -due mixture of air admitted at the proper time and temperature to the -furnace. (3) A proportionate area between the boiler and the surface of -the grates for the proper mixing of the gases arising from combustion. -(4) A correct proportion between the grate surface, the total area of -the tubes and the height and area of the chimney. - -The principal parts and appendages of a furnace are as follows: - -_The furnace_ proper or fire box, being the chamber in which the -solid constituents of the fuel and the whole or part of its gaseous -constituents are consumed. - -_The grate_, which is composed of alternate bars and spaces, to support -the fuel and to admit the air. - -_The dead-plate_, that part of the bottom of the furnace which consists -of an iron plate simply. - -_The mouth piece_, through which the fuel is introduced and often some -air. The lower side of the mouth piece is the dead plate. - -_The fire door_: Sometimes the duty of the fire door is performed by a -heap of fuel closing up the mouth of the furnace. - -_The furnace front_ is above and on either side of the fire door. - -_The ash pit._ As a general rule the ash pit is level, or nearly so, -with the floor on which the fireman stands, and as for convenient -firing, the grate should not be higher than 28 to 30 inches, the depth -of ash pit is thereby determined. - -_The ash pit door_ is used to regulate the admission of air. - -_The bridge wall._ - -_The combustion or flame chamber._ - -[Illustration: Fig. 107.] - -[Illustration: Fig. 108.] - -[Illustration: Fig. 109.] - -[Illustration: Fig. 110.] - -The arrangement of the space behind the bridge wall is found usually to -be in some one of the following forms: Level from bridge wall to back -(Fig. 107). A square box, depth ranging from 15 inches to 6 feet (Fig. -108). A gradual rise from bridge to back end of boiler, where only six -inches is found and generally circular in form (Fig. 109). A gradual -slope toward back, leaving a distance of about 36 inches from boiler -(Fig. 110). - -The advocates of Fig. 107 claim that the office of the flame is to -get into as close contact with the bottom as possible, and this form -compels the flame to do so. In burning soft coal this form is found to -soot up the bottom of the boiler very badly. - -Fig. 108 is followed more extensively than any other, the variations -being the depth of chamber; with depth generally from 36 to 40 inches. - -Fig. 109 has nothing to commend it, except in cases where bridge is too -low. - -Fig. 110 is followed a great deal and gives very good satisfaction. -This form allows for the theory of combustion, namely, the expansion of -the gases after leaving bridge wall. - -Space behind the bridge wall should be enlarged, as it will reduce the -velocity of fire gases, and thus have them give up more of their heat -to the boiler. - -The bridge wall should not be less than 18 inches at bottom, but may be -tapered off toward top to 9 or 13 inches. - - -SETTING OF WATER TUBE BOILERS. - -On page 67, Fig. 26, is exhibited a steam boiler with inclined tubes. -The setting in this style of boilers is as follows: - -A brick wall is laid for the front with suitable openings for the doors -of the furnace and ash pit, and protected on the outside by a front of -cast iron, and on the inside by a lining of fire brick. - -At the back of the grates a bridge wall is run up to the bottom of the -inclined water tubes, so that the hot gases that arise over it must -circulate among the tubes. - -A counter wall is laid on an incline from the top of the tubes to the -back of the drum. This is laid on perforated plates or bars and is -covered with fire brick. A wall is also built at the lower and back end -of the tubes to carry them. - -Back of the whole is the outer wall with openings for giving access -to the tubes and smoke chambers. Side walls are raised to enclose the -same and are arched at the top to come nearly in contact with the drum, -which is carried partly by brackets and partly by the connections to -the tubes. - - -POINTS RELATING TO BOILER SETTING. - -Long and heavy boilers are best suspended from two beams or girders by -two or three bolts at each end. Boilers over 40 feet long should have -three or even four sets of hangers, as the case may require. - -Side brackets resting on masonry may be used for short boilers. If used -on long boilers, side plates or expansion rollers should be used at -one end of boiler. There ought to be not more than two brackets on one -side, so divided that the distance between them is about three-fifths -of the total length of the boiler, or the distance from ends of boiler -to center of bracket is equal to one-fifth the length of boiler. - -The side walls in boiler-setting should not be less than twenty inches -with a two inch air space; the rear wall may vary from 12 to 16 inches -according to the size of the boiler; the front wall 9 inches and the -bridge wall may be from 18 to 24 and perfectly straight across the rear -of the furnace. If the boilers are supported by side walls, the outside -walls should be not less than 13 inches thick and have pilasters where -the boiler is resting. - -Flues touching the boiler above the water space should be emphatically -condemned. - -Unless the boiler walls are very heavy, they should be stayed by cast -or wrought iron bunch stays, held together by rods at tops and bottoms. - -It is dangerous to have large spaces in which gases may collect for -sudden ignition, producing the so-called “back draft.” - -Connections between the rear end of the boiler and brickwork is best -made with cast-iron plates or fire-brick, suspended, when boilers are -suspended, as the expansion and contraction will destroy an arch in -a short time. If resting on mud-drum stand, this connection can be -arched, as in this case the rear end of boiler will remain stationary. - -If the draughts from the different boilers come in the same direction, -or nearly so, no special provision is necessary, but if the draught -enters from directly opposite directions a centre wall should be -provided. - -An advantage claimed for water in the ash pit is: by the dropping -of hot ashes and cinders from the grate into the water, steam is -generated, which, in passing through the hot coal lying on the grate, -is there divided into oxygen and hydrogen, thus helping the combustion. - -A dry brick will absorb a pound of water, and it is the water in the -mortar that causes it to set, and harden. To prevent this loss of the -water of crystalization, and give it time to harden and adhere to the -brick, the brick must be well saturated with water, before they are -laid. - -Whenever steam is allowed to come in contact with mortar or cement an -injurious effect is produced. The action of the steam is much more -rapid than that of air and water, or water alone, when in abundance, -as the effect of the steam in every case is to soften the mortar and -penetrate to a greater depth than water could possibly do. - -The distance between the rear head of the boiler and brickwork should -not be less than 12 inches. - -In setting steam boilers, allowance must be made for the expansion -and contraction of the structure and this is usually done by placing -rollers under the rear lug or side bearing of the boiler. Care should -be exercised that the boiler rests are always in good condition so that -they may move freely and not place the boiler in any danger of sticking -and buckling. - - - - -KINDLING A FURNACE FIRE. - - -In kindling a coal fire in a furnace the phosphorus of a match inflames -at so low a temperature (150 degrees Fahr.) that mere friction ignites -it, and in burning (combining with oxygen of the air) it gives out heat -enough to raise the sulphur of the match to the temperature of ignition -(500 degrees Fahr.), which, combining in its turn with the oxygen of -the atmosphere, gives out sufficient heat to raise the temperature -of the wood to the point of ignition (800 degrees Fahr.), and at -this temperature the wood combines with oxygen supplied by the air, -giving out a temperature sufficient to raise the coal to the point -of ignition (1000 degrees Fahr.), and the coal then combines with the -free oxygen of the air, the ensuing temperature in the furnace varying, -according to circumstances, from 3000 degrees to 4000 degrees Fahr. -Thus we see that the ignition of the coal is the last of a series of -progressive steps, each increasing in temperature. - -And in each step it will be noted that a combination of oxygen is the -essential connecting link and _that the oxygen is supplied in each -instance at the same average temperature_—this fact contains a “point” -relating to supplying furnaces with so called “hot air.” - - -SAWDUST FURNACE. - -[Illustration: Sawdust Furnace Section] - -Referring also to page 33 for information relating to the burning of -sawdust and shavings S. S. Ingham, _in the Stationary Engineer_, says -upon this important matter: - -“Regarding a furnace for burning sawdust, I submit the accompanying -cuts. I have built numbers of these oven furnaces for burning this fuel -in the south, and all have given excellent results. The dimensions -are for 60″ × 16′ return tubular (4″ tubes) boiler with stack 50 per -cent. greater area than the flues; a good draft is necessary.” It will -be understood that the upper cut is designed to show end view of the -furnace whose side is shown in sectional view at the bottom of the page. - -[Illustration: Sawdust Furnace Side View] - - -GAS PIPE. - -[Illustration: Fig. 111.] - -[Illustration: Fig. 112.] - - - - -PIPES AND PIPING. - - -Next in importance after the skill necessary for the steam generator -and the engine, is the proper arrangement and care and management of -the pipes and valves belonging to a steam plant. - -It is the first thing an engineer does in taking charge of a new place, -to ascertain the exact course and operation of the water, steam, drain -and other pipes. - -Examiners for licensing marine and land engineers base their questions -much more to ascertain the applicant’s knowledge of piping than is -generally known; hence the importance of the “points” in the succeeding -pages relating to this subject. - -Pipes are used for very many purposes in connection with the boiler -room, and of course vary in size, in material and in strength, -according to the purposes for which they are designed. There are pipes -for conveying and delivering illuminating gas; pipes for conveying and -delivering drinking water, and for fire purposes; pipes for draining -and carrying off sewage and surface water; pipes for delivering hot -water under high pressure, for heating purposes and power; pipes -for delivering live steam under pressure, for heating purposes and -power; pipes for delivering compressed air, for purposes of power and -ventilation; pipes for conveying mineral oils, etc. - -In Figs. 111, 112 113 and 114 are given approximate sizes of gas -pipe and boiler tubes, taken from the catalogue of one of the oldest -steamfitting establishments in the country. It will be observed that -the size of gas pipe is computed from the internal diameter, while -boiler tubes are estimated from the outside: thus, 3 in. gas pipe has -an external diameter of 3-1/2 inches, while 3 in. boiler tubes have an -outside diameter of 3 inches only. It may be noted that boiler-tubes -are made much more accurately as to size than gas pipe; this is -especially true of the outside surfaces which are much smoother in one -case than in the other. - -BOILER TUBES. - -[Illustration: Fig. 113.] - -[Illustration: Fig. 114.] - - SURFACES AND CAPACITIES OF PIPES. - - ---------------+-----+-----+------+------+------+------ - SIZES OF PIPES.| 1/2 | 3/4 | 1 | 1-1/4| 1-1/2| 2 - | in. | in. | in. | in. | in. | in. - ---------------+-----+-----+------+------+------+------ - 1. Outside | | | | | | - circumferences | | | | | | - of pipes in | | | | | | - inches |2.652|3.299|4.136 | 5.215| 5.969|7.461 - | | | | | | - 2. Length of | | | | | | - Pipe in feet to| | | | | | - give a square | | | | | | - foot of outside| | | | | | - surface |4.52 |3.63 |2.90 | 2.30 | 2.01 |1.61 - | | | | | | - 3. Number of | | | | | | - square feet of | | | | | | - outside surface| | | | | | - in ten lineal | | | | | | - feet of Pipe |2.21 |2.74 |3.44 | 4.34 | 4.97 |6.21 - | | | | | | - 4. Cubic in. | | | | | | - of internal | | | | | | - capacity in | | | | | | - ten lineal feet| | | | | | - of pipe |36.5 |63.9 |103.5 | 179.5| 244.5|402.6 - | | | | | | - 5. Weight in | | | | | | - lbs. of water | | | | | | - in ten lineal | | | | | | - feet of pipe | 1.38| 2.31| 3.75 | 6.5 | 8.8 | 14.6 - ---------------+-----+-----+------+------+------+------ - - ---------------+-----+-----+------+------+------+------ - SIZES OF PIPES.|2-1/2| 3 | 3-1/2| 4 | 4-1/2| 5 - | in. | in. | in. | in. | in. | in. - ---------------+-----+-----+------+------+------+------ - 1. Outside | | | | | | - circumferences | | | | | | - of pipes in | | | | | | - inches |9.932|10.99| 12.56| 14.13| 15.70|17.47 - | | | | | | - 2. Length of | | | | | | - Pipe in feet to| | | | | | - give a square | | | | | | - foot of outside| | | | | | - surface |1.32 |1.09 | .954 | .849 | .763 | .686 - | | | | | | - 3. Number of | | | | | | - square feet of | | | | | | - outside surface| | | | | | - in ten lineal | | | | | | - feet of Pipe |7.52 |9.16 | 10.44| 11.78| 13.09|16.56 - | | | | | | - 4. Cubic in. | | | | | | - of internal | | | | | | - capacity in | | | | | | - ten lineal feet| | | | | | - of pipe |573.9|886.6|1186.4|1527.6|1912.6|2398.8 - | | | | | | - 5. Weight in | | | | | | - lbs. of water | | | | | | - in ten lineal | | | | | | - feet of pipe | 20.8| 32.1| 43.6 | 55.4 | 69.3 | 86.9 - ---------------+-----+-----+------+------+------+------ - -Pipe manufactured from double thick iron is called X-strong pipe, and -pipe made double the thickness of X-strong is known as XX-strong pipe. -Both X-strong and XX-strong pipe are furnished plain ends—no threads, -unless specially ordered. - -The table “Data relating to iron pipe” will be found especially useful -to the engineer and steam fitter. The size of pipes referred to in -the table range from 1/8 to 10 inches in diameter. In the successive -columns are given the figures for the following important information: - - 1. Inside diameter of each size. - 2. Outside diameter of each size. - 3. External circumference of each size. - 4. Length of pipe per square foot of outside surface. - 5. Internal area of each size. - 6. External area of each size. - 7. Length of pipe containing one cubic foot. - 8. Weight per foot of length of pipes. - 9. Number of threads per inch of screw. - 10. Contents in gallons (U. S. measure) per foot. - 11. Weight of water per foot of length. - - DATA - RELATING TO IRON PIPE. - +---------+---------+--------------+----------+---------+---------+ - | | | | Length of| | | - | Inside | Outside | External | Pipe per |Internal |External | - |Diameter.|Diameter.|Circumference.| sq. ft. | Area. | Area. | - | | | |of Outside| | | - | | | | Surface. | | | - +---------+---------+--------------+----------+---------+---------+ - | Inches. | Inches. | Inches. | Feet. | Inches. | Inches. | - | 1/8 | .40 | 1.272 | 9.44 | .012 | .129 | - | 1/4 | .54 | 1.696 | 7.075 | .049 | .229 | - | 3/8 | .67 | 2.121 | 5.657 | .110 | .358 | - | 1/2 | .84 | 2.652 | 4.502 | .196 | .554 | - | 3/4 | 1.05 | 3.299 | 3.637 | .441 | .866 | - | 1 | 1.31 | 4.134 | 2.903 | .785 | 1.357 | - | 1-1/4 | 1.66 | 5.215 | 2.301 | 1.227 | 2.164 | - | 1-1/2 | 1.9 | 5.969 | 2.01 | 1.767 | 2.835 | - | 2 | 2.37 | 7.461 | 1.611 | 3.141 | 4.430 | - | 2-1/2 | 2.87 | 9.032 | 1.328 | 4.908 | 6.491 | - | 3 | 3.5 | 10.996 | 1.091 | 7.068 | 9.621 | - | 3-1/2 | 4. | 12.566 | .955 | 9.621 | 12.566 | - | 4 | 4.5 | 14.137 | .849 | 12.566 | 15.904 | - | 4-1/2 | 5. | 15.708 | .765 | 15.904 | 19.635 | - | 5 | 5.56 | 17.475 | .629 | 19.635 | 24.299 | - | 6 | 6.62 | 20.813 | .577 | 28.274 | 34.471 | - | 7 | 7.62 | 23.954 | .505 | 38.484 | 45.663 | - | 8 | 8.62 | 27.096 | .444 | 50.265 | 58.426 | - | 9 | 9.68 | 30.443 | .394 | 63.617 | 73.715 | - | 10 | 10.75 | 33.000 | .355 | 78.540 | 90.792 | - +---------+---------+--------------+----------+---------+---------+ - - +---------+----------+----------+----------+-----------+----------+ - | | Length | Weight | No. of | Contents |Weight of | - | Inside | of Pipe | per ft. | Threads | in |Water per | - |Diameter.|containing| of |per inch |Gallons[A] | foot of | - | |one Cubic | Length. |of Screw. |per foot. | Length. | - | | Foot. | | | | | - +---------+----------+----------+----------+-----------+----------+ - | Inches. | Feet. | Lbs. | | | Lbs. | - | 1/8 | 2500. | .24 | 27 | .0006 | .005 | - | 1/4 | 1385. | .42 | 18 | .0026 | .021 | - | 3/8 | 751.5 | .56 | 18 | .0057 | .047 | - | 1/2 | 472.4 | .84 | 14 | .0102 | .085 | - | 3/4 | 270. | 1.12 | 14 | .0230 | .190 | - | 1 | 166.9 | 1.67 | 11-1/2 | .0408 | .349 | - | 1-1/4 | 96.25 | 2.25 | 11-1/2 | .0638 | .527 | - | 1-1/2 | 70.65 | 2.69 | 11-1/2 | .0918 | .760 | - | 2 | 42.36 | 3.66 | 11-1/2 | .1632 | 1.356 | - | 2-1/2 | 30.11 | 5.77 | 8 | .2550 | 2.116 | - | 3 | 19.49 | 7.54 | 8 | .3673 | 3.049 | - | 3-1/2 | 14.56 | 9.05 | 8 | .4998 | 4.155 | - | 4 | 11.31 | 10.72 | 8 | .6528 | 5.405 | - | 4-1/2 | 9.03 | 12.49 | 8 | .8263 | 6.851 | - | 5 | 7.20 | 14.56 | 8 | 1.020 | 8.500 | - | 6 | 4.98 | 18.76 | 8 | 1.469 | 12.312 | - | 7 | 3.72 | 23.41 | 8 | 1.999 | 16.662 | - | 8 | 2.88 | 28.34 | 8 | 2.611 | 21.750 | - | 9 | 2.26 | 34.67 | 8 | 3.300 | 27.500 | - | 10 | 1.80 | 40.64 | 8 | 4.081 | 34.000 | - +---------+----------+----------+----------+-----------+----------+ - -[Footnote A: The Standard U. S. gallon of 231 cubic inches.] - -The division of process in the manufacture of pipe, takes place at -1-1/4 inch, 1-1/4 inch and smaller sizes being called butt-welded pipe, -and 1-1/2 inch and larger sizes being known as lap-welded pipe; this -rule holds good for standard, X-strong and XX-strong. - - -JOINTS OF PIPES AND FITTINGS. - -The accompanying illustrations represent certain joints, couplings and -connections used in steam and hot water heating systems. - -[Illustration: Fig. 115.] - -[Illustration: Fig. 116.] - -For many years in the matter of pipe joints there has been little -change. The cast-iron hub and spigot joint, Fig. 115, caulked with iron -borings, is probably the oldest kind of joint. This is still generally -adopted in hot water heating of a certain class, and was formerly used -with low-pressure steam. A fairly regular smooth internal service -is obtained, and once made tight is very durable. Cast-iron flanged -pipes have also been a long time in use. These joints are made with a -wrought-iron ring gasket, wrapped closely with yarn, Fig. 116, which -is sometimes dipped in a mixture of red and white lead. It is placed -between the flanges, it being of such a diameter as to fit within the -bolts by which the joint was screwed up and a nest or iron joint, B B, -caulked outside the annular gasket between the faces of the flanges. - -The next step in cast-iron flange pipe joints was the facing or turning -up of the flanges and the use of a gasket of rubber, copper, paper or -cement, with bolts for drawing the faces together. These joints for -cast-iron pipes have not been changed excepting for some classes of -work where a lip and recess, Fig. 117, formed on opposite flanges, -which makes the internal surfaces smooth and aid in preventing the -gaskets from being blown out. - -[Illustration: Fig. 117.] - -[Illustration: Fig. 118.] - -[Illustration: Fig. 119.] - -[Illustration: Fig. 120.] - -The introduction of wrought iron welded pipes has diminished the use -of cast-iron pipes for many purposes, especially in heating apparatus -and other pipe systems. Its advantages are lightness, the ease with -which various lengths can be obtained and its strength. In wrought-iron -pipe work the general practice in making joints between pipes is a -wrought-iron coupling, Fig. 118, with tapered threads at both ends. -The pipes do not meet at their ends, and a recess of about 3/4 inch -or more long by the depth of the thickness of the pipes is left at -every pipe end. A similar tapered thread is used in connecting the -cast-iron fittings, elbows, tees, etc., Fig. 119, to the pipe, and a -large recess is necessary in each fitting to allow for the tapping of -the threads. Thus the inside diameter of the fitting is larger by 1/8 -inch than the outside diameter of the pipe, and the internal projection -of the thickness of the pipe and that of the thread of the fitting -increases materially the friction due to the interior surfaces of pipe -and fitting. This class of joint requires care in the tapping of the -fittings and in the cutting of tapered threads on the pipes; much -trouble is caused by an inaccurately cut thread, as it may throw a line -of pipes several inches out of place and put fittings and joints under -undue and irregular strains. - -[Illustration: Fig. 121.] - -[Illustration: Fig. 122.] - -The right and left threaded nipple, Fig. 119, is used as a finishing -connection joint and between fittings. Space equal to the length of the -two threads is required between the two fittings to be connected in -order to enter the nipple, and one or both fittings should be free to -move in a straight line when the nipple is being screwed up. To make -up this joint time and care are necessary. The right threaded end on -nipple should be first firmly screwed with the tongs or wrench into the -right threaded end of fitting, then slacked out and screwed up again -by hand until tight, when it is screwed back by hand, at the same time -counting the number of threads it has entered by hand. The same is done -with the left threaded end of nipple and fitting. If the right and left -threads of nipple have counted the same number of threads, each thread, -when making the joint up, should enter the fittings at the same time -if possible, and particular care must be taken that the fittings are -exactly opposite, to facilitate catching on, prevent crossing threads, -and that no irregular strain comes on the nipple while being screwed up. - -In screwing up these nipples the coupling has to be turned with flats -on the external surface to fit an internal wrench: in such cases the -thread on nipple has one continuous taper. These special couplings -are marked with ribs on the outside to distinguish them. Fig. 120 -represents another joint in wrought-iron piping known as the “union” -composed of three pieces of the washer. Unions are also made with -ground joints, and the washer dispensed with. Radiator valves are now -generally connected by them, but if the hole in the radiator is not -tapped accurately, the union when drawn up will not be tight, or if -tight, the valve will not be straight. - -Fig. 121 shows right and left threaded nipple connecting elbow and tee -with wrought-iron pipes. - -The flange union, Fig. 122, is another joint generally used on -wrought-iron pipes above 4 or 5 inches in diameter in making -connections to valves, etc., and on smaller pipes in positions where it -is a convenient joint. This joint consists of two circular cast-iron -flanges with the requisite number of holes for bolts, and central hole -tapped tapered to receive thread of pipe. The abutting faces of the -flanges are generally turned and the holding bolts fitted into the -holes. - - - - -STEAM AND HOT WATER HEATING. - - -The heating by means of pipes through which are conveyed hot water -and steam is a science by itself and yet one claiming some degree of -familiarity by all engineers, steam users, and architects. - -[Illustration: Fig. 123.] - -[Illustration: Fig. 124.] - -In practice it requires a knowledge of steam, air and temperatures, -of pressure and supply; a familiarity with heat and heating surfaces -and with all contrivances, appliances and devices that enter into the -warming and ventilation of buildings. So long as factories, public and -private buildings are erected, so long will warming and ventilation -keep progress with steam engineering and remain a part of the general -mechanical science required of the supervisory and practical engineer. - -In what is called _the system of open circulation_, a supply main -conveys the steam to the radiating surfaces, whence _a return main -conducts the condensed water either into an open tank for feeding the -boiler, or into a drain to run to waste_, the boiler being fed from -some other source; the system of what is called _closed circulation_ -is carried out either with separate supply and return mains, both of -which extend to the furthest distance to which the heat has to be -distributed, or else with a single main, which answers at once for -both the supply and the return, either with or without a longitudinal -partition inside it for separating the outward current of steam supply -from the return current of condensed water. - -In either case suitable traps have to be provided on the return -main, _for preserving the steam pressure within the supply main and -radiators_. These two systems, in any of their modifications, may -also be combined, as is most generally done in any extensive warming -apparatus. - -The system of closed circulation requires the boiler to be placed so -low as will allow all the return pipes to drain freely back to it above -its water-level. This condition has been modified mechanically by the -automatic “trap,” a device frequently employed for lifting from a lower -level, part or all of the condensed water, and delivering it into the -boiler; it is, in fact, a displacement pump. - -The same result has been attained by draining into a closed tank, -placed low enough to accommodate all the return pipes, and made -strong enough to stand the full boiler pressure with safety, and then -employing a steam pump, either reciprocating or centrifugal, to raise -the water from this tank to the proper level for enabling it to flow -back into the boiler, the whole of the circulation being closed from -communication with the atmosphere. - -[Illustration: Fig. 125.] - -[Illustration: Fig. 126.] - -[Illustration: Fig. 127.] - -There are two systems of steam heating, known as the _direct_ and the -_indirect_ system. - -Direct radiating surfaces embrace all heaters placed within a room or -building to warm the air, and are not directly connected with a system -of ventilation. - -Indirect radiation embraces all heating surfaces placed outside the -rooms to be heated, and can only be used in connection with some system -of ventilation. - -For warming by direct radiation, the radiators usually consist of -coils, composed of 3/4-inch and 1-inch steam pipes, which are arranged -in parallel lines and are coupled to branch tees or heads. In a -few exceptional cases, radiators of peculiar shapes are specially -constructed. In all cases the coils must have either vertical or -horizontal elbows of moderate length, for allowing each pipe to expand -separately and freely. Sometimes short lengths of pipe are coupled by -return-bends, doubling backwards and forwards in several replications -one above another, and forming what are called “return-bend coils,” and -when several of these sections are connected by branch, tees into a -compact mass of tubing, the whole is known as a “box-coil.” - -Steam and Hot Water heating have long been acknowledged as altogether -most practical and economical in every way—and their universal adoption -in all the better class of buildings throughout the country is positive -proof of their superiority. - -[Illustration: Fig. 128.] - -[Illustration: Fig. 129.] - -[Illustration: Fig. 130.] - -The heat from steam is almost exactly identical with that from hot -water, and few can distinguish between the two systems when properly -erected. - -They are both healthful, economical and satisfactory methods of -warming. They give no gas, dust nor smoke; are automatically regulated, -and therefore allow of an even and constant temperature throughout the -house, whatever be the condition of the weather outside. - -The circulation of the steam through the warming pipes is effected -in an almost unlimited variety of ways, and the cause producing the -circulation throughout the pipes of the warming apparatus is solely -the difference of pressure which results from the more or less rapid -condensation of the steam in contact with the radiating surfaces. - -A partial vacuum is formed by this difference of pressure _within -the radiating portions of the apparatus_, and the column of steam or -of water equivalent to this diminution of pressure, constitutes the -effective head producing the flow of steam from the boiler, at the -same time the return current of condensed water is determined by the -downward inclination of the pipes for the return course. - - -POINTS RELATING TO STEAM HEATING. - -No two pipes should discharge into a T from opposite directions, thus -retarding the motion of both or one of the returning currents. This is -called “butting” and is one of the most vexatious things to encounter -in pipe fitting. - -[Illustration: Fig. 131.] - -[Illustration: Fig. 132.] - -[Illustration: Fig. 133.] - -All steam piped rooms should be frequently dusted, cleaned and kept -free from accumulation of inflammable material. - -The use of the air valve is as follows: In generating steam from cold -water all the free air is liberated and driven off into the pipe, with -the air left in them, all of which is forced up to the highest point -of the coils or radiators, and compressed equal to the steam pressure -following it. Now, by placing a valve or vent at the return end of the -pieces to be heated, the air will be driven out by the compression. Why -the vent is placed at the return is, that the momentum of the steam, it -being the lightest body, will pass in the direction of it, falling down -into the return as it condenses, thus liberating the air. Otherwise, -should the vent not work, and the air is left in the radiator, it will -act as an air spring, and the contents of the pipes left stationary -will be the result; no circulation, no heat; and the greater steam -pressure put on, the greater the chances are of not getting any heat; -and thus a little device, with an opening no larger than a fine needle, -will start what a ton of pressure would not do in its absence. - -If the drip and supply pipes are large there is very little danger of -freezing, provided suitable precautions are taken to leave the pipes -clear. They should be blown through, when left, and the steam valve -should be closed. There should also be a free chance for air to escape -in all systems of piping. - -No rule can be given relating to capacity for heating pipes and -radiators which do not require to be largely modified by surroundings. - -The field of steam heating would seem to be limitless—in one public -building it required recently 480,000 dollars to meet the expenditures -in this single line. As an example of warming on an extensive scale may -be taken a large office in New York, of which the following are the -particulars: - - Total number of rooms, including halls and vaults. 286 - Total area of floor surface. sq. ft. 137,370 - Total volume of rooms. cub. ft. 1,923,590 - -A second example is furnished by the State Lunatic Asylum at -Indianapolis: - - Length of frontage of building, more than. 2,000 lin. ft. - Total volume of rooms. 2,574,084 cub. ft. - Warming {indirect radiating surface 23,296 - Apparatus {Direct 10,804 - {Total 34,100 sq. ft. - Boilers {Grate area 180 sq. ft. - {Heating surface 5,863 sq. ft. - -The “overhead” system of heating with steam pipes has several -advantages. 1. The pipes are entirely out of the way 2. They do not -become covered with odds and ends of unused materials. 3. If they leak -the drip fixes the exact location of place needed to be repaired. 4. -The room occupied overhead cannot be well otherwise utilized, hence in -shops the system has proved efficient. - -But for offices or store rooms the overhead system is not approved of -owing to the heat beating down upon the occupants and causing headache. - -When overhead heating pipes are used, they should not be hung too near -the ceiling. If the room be a high one, it is better to hang them -below, rather than above, the level of the belts running across the -room, and they should not be less than three or four feet from the -wall. - -[Illustration: Fig. 134.] - -It is important to protect all wood work or other inflammable material -around steam pipes from immediate contact with them, especially where -pipes pass through floors and partitions. A metal thimble should be -placed around the steam pipe, and firmly fastened on both sides of the -floor, in such a way as to leave an air space around the steam pipe. - -For indirect radiating surfaces, the box coils are the forms most -used. The chambers or casings for containing them are made either of -brickwork, or often of galvanized sheet-iron of No. 26 gauge, with -folded joints. The coils are suspended freely within the chambers, -which are themselves attached to the walls containing the air inlet -flues. Besides coils of wrought iron tubes, cast-iron tablets or hollow -slabs, having vertical surfaces with projecting studs or ribs, have -been extensively used for the radiating surfaces. - -As the amount of heat given off from the radiator cannot be -satisfactorily controlled by throttling the steam supply, it is usual -to divide all radiators into sections, each of which can be shut off -from the supply and return mains, separately from the rest of the -sections. This method of regulation applies to radiators for indirect -heating as well as for direct. - -Vertical pipe coils, constitute a distinctive form of radiator now -largely used. In these a number of short upright 1-inch tubes, from -two feet 8 inches to 2 feet 10 inches long, are screwed into a hollow -cast iron base or box; and are either connected together in pairs by -return-bends at their upper ends, or else each tube stands singly with -its upper end closed, and having a hoop iron partition extending up -inside it from the bottom to nearly the top. The supply of steam is -admitted into the bottom casting; and the steam on entering, being -lighter than the air, ascends through one leg of each siphon pipe and -descends through the other, while the condensed water trickles down -either leg, and with it the displaced air sinks also into the bottom -box. For getting rid of the air, a trap is provided, having an outlet -controlled by metallic rods; as soon as all the air has escaped and the -rods become heated by the presence of unmixed steam, their expansion -closes the outlet. - -A thorough drainage of steam pipes will effectually prevent cracking -and pounding noises. - -The windward side of buildings require more radiating surface than does -the sheltered side. - -When floor radiators are used, their location should be determined -by circumstances; the best situations are usually near the walls of -the room, in front of the windows. The cold air, which always creates -an indraft around the window frames, is thus, to some extent, warmed -as it passes over the the radiators, and also assists in the general -circulation. - -Water of condensation will freeze quicker than water that has not been -evaporated, for the reason that it has parted with all its air and is -therefore solid. - -Whatever the size of the circulating pipes, the supply and drip pipes -should be large, to insure good circulation; the drip pipes especially -so. This is also the more necessary when the pipes are exposed, or when -there is danger of freezing after the steam is shut off. - -It is important to see that no blisters or ragged pipes go into the -returns, and also to make sure that the ends are not “burred in” with -a dull pipe cutter wheel so as to form a place of lodgment for loose -matter in the pipe to stop against. - -[Illustration: Figs. 135-137.] - -Experiments recently made on the strength of bent pipes have developed -some things not commonly known, or at least not recognized, that is, -the strain on the inside of the angles, _due to the effort of the -pipes to straighten themselves under pressure_. The problem is one of -considerable intricacy, resolvable, however, by computation, and is a -good one for practice. In the experiment referred to, a copper pipe of -6-3/4 in. bore, 3/16 in. thick, was used. The angle was 90 degrees, and -the legs about 16 in. long from the center. At a pressure of 912 pounds -to an inch, the deflection of the pipe was nearly 3/8 in., showing an -enormous strain on the inner side, in addition to the pressure. - -Steam valves should be connected in such a manner that the valve closes -against the constant steam pressure. - -Interesting experiments show that the loss by condensation in carrying -steam one mile is 5 per cent. of the capacity of the main, and a steam -pressure of seventy-five pounds carried in five miles of mains, ending -at a point one-half mile from the boiler house only shows a loss of -pressure of two pounds. - -In steam warming it is necessary to bring the water to a boiling point -to get any heat whatever; in hot water warming, a low temperature will -radiate a corresponding amount of heat. - -Never use a valve in putting in a low pressure apparatus if it is -possible to get along without it. All the valves or cocks that are -actually required in a well-proportioned low pressure apparatus are, a -cock to blow off the water and clean out the return pipes, another to -turn on the feed water. Of course the safety valves, gauge cocks, and -those to shut fire regulators and such as are a part of the boiler, are -not included in this “point.” - -The most important thing in connecting the relief to return pipes is, -that it should always be carried down below the line, the same as all -vertical return pipes. In connecting the reliefs, so that the lower -opening can at any time be exposed to the steam, there will be the -difficulty of having the steam going in one direction, and the water in -another. - -The relief pipe should “tap” the steam at its lowest or most depressed -points. It should always be put in at the base of all steam “risers” -taking steam to upper floors. - -In leaving the boiler with main steam pipe, raise to a height that will -allow of one inch fall from the boiler to every ten feet of running -steam pipe; this is sufficient, and a greater fall or pitch will cause -the condensed water in the pipe to make at times a disagreeable noise -or “gurgling.” - -The flow pipe should never start from the boiler in a horizontal -direction, as this will cause delay and trouble in the circulation. -This pipe should always start in a vertical direction, even if it -has to proceed horizontally within a short distance from the boiler. -Reflection will show that the perfect apparatus is one that carries -the flow pipe in a direct vertical line to the cylinder or tank; this -is never, or but rarely possible, but skill and ingenuity should be -exercised to carry the pipes as nearly as possible in this direction. - -The flow of steam ought not to be fast enough to prevent the water of -condensation from returning freely. All the circulating pipes should be -lowest at the discharge end, and the inclination given them should not -be less than one foot in fifty. - -[Illustration: Fig. 138.] - -[Illustration: Fig. 139.] - -[Illustration: Fig. 140.] - -[Illustration: Fig. 141.] - -The general rule is to lay the main pipes from the boiler so that the -pipe will drain from the boiler. Where this is done it is necessary to -have a drip just before the steam enters the circulation. This drip -is connected to a trap, or, if the condensed water is returned to the -boiler, the drip is arranged accordingly. - -But it is the best practice to lay the main pipe with the lowest part -at the boiler, so that the drip will take care of itself, and not -require an extra trap, nor interfere with the return circulation. - -When steam is turned into cold pipes the water of condensation gets -cold after running a short distance, and if it has to go through a -small drip pipe full of frost it will probably be frozen. Then, unless -it is followed up with a pail of hot water, the whole arrangement will -be frozen and a great many bursted pipes will result. Whenever turning -steam on in a system of very cold pipes, only one room should be taken -at a time, and a pail of hot water should be handy so that if the pipe -becomes obstructed it can be thawed immediately without damage. - -When pipes become extensively frozen there is nothing to do but take -them out and put in new ones. - -[Illustration: Fig. 142.] - -[Illustration: Fig. 143.] - -The manner in which a temperature too low to start rapid combustion -in wood in steam pipes, operates in originating a fire is by first -reducing the oxide of iron (rust) to a metallic condition. This is -possible only under certain external conditions, among them a dry -atmosphere. _Just as soon as the air is recharged with moisture, the -reduced iron is liable to regain, at a bound, its lost oxygen, and -in doing so become red hot._ This is the heat that sets the already -tindered wood or paper ablaze. - -Where there is no rust there is no danger from fire with a less than -scorching temperature in the pipe or flue. Hence the necessity of -keeping steam or hot water fittings in good order. - -The indirect system of heating is the most expensive to put in; as to -the cost of providing nearly double the heating surface in the coils -must be added the cost of suitable air boxes, pipes and registers. For -a large installation, this is a serious matter, although for office -warming the advantages gained on the score of healthfulness and greater -efficiency of employees much more than counterbalance the extra expense. - -One horse power of boiler will approximately heat 6,000 to 10,000 cubic -feet in shops, mills and factories—dwellings require only one horse -power for from 10,000 to 20,000 cubic feet. - -From seven to ten square feet of radiating surface can be heated from -_one square foot of boiler surface_, _i.e._, the heating surface of the -boiler and each horse power of boiler will heat 240 to 360 feet of -1-inch pipe. - -The profession most nearly related to that of steam engineers is the -working steam fitters’ occupation. Strictly speaking, the engineer -should produce the steam, and it is the steam fitters’ place to fix -up all the steam pipes and make all the necessary connections: but -where the steam plants are small, the engineer may be steam fitter -also: hence the introduction in this work of these “Points” which are -necessary to be known for the proper care and management of any system -of steam or hot water heating. - -The care and patience, the mental strain and not infrequently the -physical torture incident to fitting up a complicated pipe system -cannot adequately be set forth in words. - -It is stated to be a fact, that in high pressure hot water heating the -water frequently becomes red hot, pressures of 1000 to 1200 pounds per -square inch being reached, and when the circulation of the system is -defective the pipe becomes visibly red in the dark. - -Pipes under work benches should be avoided, unless there is an opening -at the back to permit the escape of the heated air, which would -otherwise come out at the front. - -When both exhaust and live steam are used for heating, many engineers -prefer to use independent lines of pipe for each, rather than run -the risk of interference and waste caused by admitting exhaust and -live steam into the same system at the same time. Nevertheless, the -advantages gained by being able to increase the heating power of a -system in extremely cold weather by utilizing the entire radiating -surface for high pressure steam, are so great that it is probably -better so to arrange the system of pipes and connections that this can -be done. - -Double extra heavy pipe (XX) is used for ice and refrigerating machines -(see page 246), as a general rule, makers of this class of machinery -obtain but little satisfaction in the use of the ordinary thread -joining and use special dies _with uniform taper_—both for couplings, -flanges and threading the pipe itself. They do this to protect their -reputation and guarantees. - -_Welding boiler and other tubes._—The following is a good way in cases -of emergency and can be done on a common forge: - -Enlarge one end of the shortest piece, and one end of the long piece -make smaller, then telescope the two about 3/4 of an inch. Next get an -iron shaft as large as will go into the tube and lay across the forge -with the tube slipped over it. _Block the shaft up so that the tube -will hang down from the top of the shaft._ By such an arrangement the -inside of the tube will be smooth for a scraper. When the tube gets to -a welding heat strike on the _end_ of the short piece first, with a -heavy hammer, then with a light and broad-faced hammer make the weld. -Borax can be used to good advantage, but it is not necessary. The next -thing is to test the tube, which can be done in the following manner: -Drive a plug in one end of the tube, stand it up on that end, and fill -it with water, if it does not leak the job is well done, if a leak -exists the welding must be again done. - -SOLID-DRAWN IRON TUBES: CALCULATED BURSTING AND COLLAPSING PRESSURES. - - ---------+----------+---------+------------------+-------------------- - | | |BURSTING PRESSURE.|COLLAPSING PRESSURE. - External | |Internal +------------------+-------------------- - Diameter.|Thickness.|Diameter.|Per Square Inch of|Per Square Inch of - | | +--------+---------+---------+---------- - | | |Internal| Section |External | Section - | | |Surface.|of Metal.|Surface. | of Metal. - ---------+----------+---------+--------+---------+---------+---------- - Inches. | Inch. | Inches. | Lbs. | Tons. | Lbs. | Tons. - 1-1/4 | .083 | 1.084 | 7700 | 22.4 | 6500 | 21.7 - 1-3/8 | .083 | 1.209 | 6900 | 22.4 | 5800 | 21.3 - 1-1/2 | .083 | 1.334 | 6200 | 22.4 | 5200 | 21.0 - 1-3/4 | .083 | 1.584 | 5300 | 22.4 | 4300 | 20.3 - 2 | .083 | 1.834 | 4500 | 22.4 | 3700 | 19.7 - 2-1/4 | .095 | 2.060 | 4600 | 22.4 | 3600 | 19.0 - 2-1/2 | .109 | 2.282 | 4800 | 22.4 | 3600 | 18.3 - 2-3/4 | .109 | 2.532 | 4400 | 22.4 | 3100 | 17.7 - 3 | .120 | 2.760 | 4300 | 22.4 | 3000 | 17.0 - 3-1/2 | .134 | 3.232 | 4200 | 22.4 | 2700 | 15.7 - 3-3/4 | .134 | 3.482 | 3900 | 22.4 | 2400 | 15.0 - 4 | .134 | 3.732 | 3600 | 22.4 | 2100 | 14.3 - 4-1/2 | .134 | 4.232 | 3200 | 22.4 | 1700 | 13.0 - 4-3/4 | .134 | 4.482 | 3000 | 22.4 | 1600 | 12.3 - 5 | .134 | 4.732 | 2800 | 22.4 | 1400 | 11.7 - 5-1/2 | .148 | 5.204 | 2800 | 22.4 | 1200 | 10.3 - 6 | | 5.704 | 2600 | 22.4 | 1000 | 9.0 - ---------+----------+---------+--------+---------+---------+---------- - - -VENTILATION. - -The quantity of air for each minute for one person is from four to -fifteen feet—and from one-half to one foot should be allowed for each -gas jet or lamp. - -Heated air cannot be made to enter a room unless means are provided for -permitting an equal quantity to escape, and the best places for such -exit openings is near the floor. - -For healthful ventilation the indirect system of steam heating is by -far the best yet devised, for it not only warms the room, but insures -perfect ventilation as well. In this system, the air for warming the -room is introduced through registers, having first been heated by -passing over coils of pipe or radiators suitably located in the air -ducts. There is a large volume of pure air constantly entering the -room, which must displace and drive out an equal quantity of impure -air. This escapes principally around the doors and windows, so that -not only is the ventilation effected automatically without the use of -special devices, but all disagreeable indraft of cold air is prevented. - -One of the cheapest and best methods of ventilation is to have an -opening near the floor, opening directly into the flue, or some other -outlet especially constructed for it, _with hot water or steam pipes -in this opening_. A moderate degree of heat in these pipes will create -a draft, and draw out the bad air. Only a few of these pipes are -necessary, and the amount of hot water or steam required to heat them -is too small to be worthy of consideration. - -The use of a small gas-jet, burning continuously, in a pipe or shaft -has been found to be a most admirable method of ventilating inside -rooms, closets and similar places where foul air might collect if not -replaced by fresh. The following table exhibits the result of careful -experiments made by Mr. Thomas Fletcher, of England, with a vertical -flue 6 inches in diameter and 12 feet high: - -TABLE. - - +-----------+-----------+-----------+--------------+---------------+ - | Gas Burnt | Speed of | Total Air |Air Exhausted |Temperature at | - | per Hour. |Current per| Exhausted |per Cubic foot| outlet. Normal| - | | Minute. | per Hour. | of Gas Burnt.| 62° Fahr. | - +-----------+-----------+-----------+--------------+---------------+ - |Cubic Feet.| Feet. |Cubic Feet.| Cubic Feet. | | - | 1 | 205 | 2,460 | 2,460 | 82° | - | 2 | 245 | 2,940 | 1,470 | 92° | - | 4 | 325 | 3,900 | 975 | 110° | - | 8 | 415 | 4,980 | 622 | 137° | - +-----------+-----------+-----------+--------------+---------------+ - -[Illustration: EXHAUST STEAM HEATING. - -Fig. 144.] - -Taking the experiments as a whole, it will be seen that in a flue 6 -inches in diameter, the maximum speed of current which can be obtained -with economy is about 200 feet per minute; and this was realized with a -gas consumption of 1 cubic foot per hour—1 cubic foot of gas removing -2,460 cubic feet of air. - -It should, however, not be required of any system of heating to more -than aid in ventilation. It is the architect’s or builder’s performance -to so arrange lower and upper openings to drive out the bad air. - - -HEATING BY EXHAUST STEAM. - -There are two methods of warming by steam heat—one with live steam -direct from the boiler, and the other with exhaust steam. These two are -frequently carried out in combination, and in fact generally so where -exhaust steam is used at all for warming. - -In nearly all manufacturing establishments, office buildings, etc., the -exhaust steam produced will very nearly, if not quite supply sufficient -exhaust steam to furnish all the heat required for heating the building -during average weather, although in extremely cold weather, a certain -amount of live steam might be necessary to use in connection with the -exhaust to supply the required amount of heat. - -A simple and convenient device operating upon the suction principle -has been found to be most efficient. By this the exhaust steam is -drawn almost instantly through the most extensive piping; preventing -condensation, freezing and hammering, after which it is condensed and -purified, and fed back into the boiler by the means of a reciprocating -pump. - -It is claimed that a given quantity of exhaust steam can be circulated -by this vacuum system and uniformly distributed through double the -amount of heating pipes than could be accomplished by the same quantity -of exhaust steam when forced into the heating system by pressure. - -Fig. 144 is a well-tried system of heating by exhaust steam in which -“7” represents the steam exhaust pipe, with “6” showing back pressure -valve with weight to adjust amount of back pressure; “4” “4” are steam -supply pipes to radiators; “5” “5” are risers; “9” “9” are condensation -return pipes from the radiators; “8” is the pressure regulating -valve from the boilers. Fig. 144 may also be said to represent the -general method of piping used in steam and hot water heating, which is -difficult of illustration owing to the fact that each locality where it -is used requires a different adaptation. - - -CARE OF STEAM FITTINGS. - -Many steam fittings are lost through carelessness, particularly in -taking down old work, but the great bulk are simply “lost” for lack -of method in caring for them. This task properly falls upon the -engineer, as he usually is intrusted with the selection and ordering -of the necessary work. A great saving in the bill of “findings” can be -effected by proper attention. - -The same systematic care exercised over the other fittings, tools, -appliances, oil, fuel, etc., used or consumed in the engine and boiler -room may be urged with equal emphasis. - - +------+-------+--------+-------+---------+-------+-------+----------+ - | | | | | | | | 1/4 and | - | | | | | | | | 3/8 in. | - +------+-------+--------+-------+---------+-------+-------+----------+ - | | | | | | | | 1/2 in. | - +------+-------+--------+-------+---------+-------+-------+----------+ - | | | | | | | | 1 in. | - +------+-------+--------+-------+---------+-------+-------+----------+ - | | | | | | | |1-1/4 in. | - +------+-------+--------+-------+---------+-------+-------+----------+ - | | | | | | | |1-1/2 in. | - +------+-------+--------+-------+---------+-------+-------+----------+ - | | | | | | R’s | | 2 in. | - |Elbows| Tees. |Nipples.| Plugs.|Reducers.| and |Unions |couplings.| - | | | | | | L’s. | | | - +------+-------+--------+-------+---------+-------+-------+----------+ - Fig. 145. - -Fig. 145 shows a case for keeping fittings, which will enable one to -find any particular piece without a moment’s delay. In this admirable -arrangement it will be seen that the heavy fittings are all at -the bottom, the light ones at the top. In the top row of all, the -one-quarter and three-eighth inch fittings are placed, being so small -that a partition may be put into that row of boxes, and then have -plenty of room, and giving twice the capacity to that row of pigeon -holes. - -Above this case, which is built of one inch boards, may be put a set of -four cupboards, double doors being fitted to each, and thus making a -door over each compartment in the fitting rack. The shelves run through -these cupboards from end to end, and are not divided by vertical -partitions. The necessary brass fittings are kept on these shelves, and -the doors are secured by good locks. The lightest fittings are placed -on the lower shelves in this cupboard, being in greatest demand. - - -TOOLS USED IN STEAM FITTING. - -[Illustration: Fig. 146.] - -Fig. 146 represents one form of a pipe cutter which is made to use by -hand; cutters are also made for use by power, which are capable of -cutting off pipes of immense size. In an engineer’s outfit of steam -fitting tools 2 sets are advisable—one to cut pipe 1/8th inch to 1 -inch, and the other to cut 1 to 2-inch pipe. Figs. 147, 148, represent -different forms of pipe tongs—the former called “chain” tongs which -will readily hold three-inch pipe. Fig. 149 represents a steam fitter’s -vise which will “take” say, 2-1/2-inch pipe down to 1/8th. Fig. -150 shows a set of taps and dies for small bolts and nuts which is -ordinarily to be found in a steam fitter’s outfit although used very -generally by machinists and others. Fig. 151 shows a pair of gas-pliers -which are used by steam fitters in gas-pipe jobs. Fig. 152 exhibits the -old-fashioned alligator wrench. - -In ice and refrigerating jobs of pipe fitting special tubes are used -to assure a niceness of joints and fitting which is not called for in -steam and water service. - -[Illustration: Fig. 147.] - -[Illustration: Fig. 148.] - -[Illustration: Fig. 149.] - - -COCKS. - -The first means in the earliest times of steam engineering, for opening -and shutting the passages in the pipes of steam engines were cocks -and these were all worked by hand and required close attention. A boy -named Humphry Potter being in charge of one of the cocks of Newcomen’s -pumping-engines, and desiring time for play, it is said, managed to -fasten the lever-handles of the spigots by means of rods and string -to the walking beam of the engine, so that each recurrent motion of -the beam effected the change required. This was the first automatic -valve-motion. - -[Illustration: Fig. 150.] - -[Illustration: Fig. 151.] - -[Illustration: Fig. 152.] - - -VALVES. - -The valve is any device or appliance used to control the flow of a -liquid, vapor or gas, through a pipe, outlet, or inlet in any form of -vessel. In this sense the definition includes air, gas, steam, and -water cocks of any kind. - -The bellows was probably the first instrument of which they formed a -part. No other machine equally ancient can be pointed out in which they -were required. - -By far the most important improvement on the primitive bellows or bag -was the admission of air by a separate opening—a contrivance that led -to the invention of the valve, one of the most essential elements of -steam, of water, as well as pneumatic machinery. - -_Valves and Cocks._—Generally described, a valve is a lid or cover to -an opening, so formed as to open a communication in one direction and -close it in another by lifting, turning, or sliding—among the varieties -may be classed as, the cock, the slide-valve, the poppet valve and the -clack-valve. A common form of this valve is shown in Fig. 139, page -261. - -An every day example of a valve, and almost the simplest known, is that -of an ordinary pump where the valve opens upward to admit the water and -closes downward to prevent its return. - -A valve has a seat, whether it be a gate or circular valve, and is -generally turned by a circular handle fitted to the spindle. - -_Difference between a cock and valve._—The cock is a valve, but a valve -is not a cock; the cock is a conical plug slotted and fitted with a -handle for turning the cone-shaped valve, with its opening in line, or -otherwise, with the opening of the pipe. - -_Globe Valve_ is a valve enclosed in a globular chamber, Fig. 135. -This, like many other valves, takes its name from its shape. - -Globe valves, whenever possible, should be placed _so that the pressure -comes under the valve_, or at the side, for if the valve should become -loose from the stem (which they often do) if the pressure is on top, -there would be a total stoppage of the steam. - -_Relief Valve_ is a valve so arranged that it opens outward when a -dangerous pressure or shock occurs; a valve belonging to the feeding -apparatus of a marine engine, through which the water escapes into the -hot well when it is shut off from the boiler. - -_Hinged Valves_ constitute a large class, as for example the -butterfly-valve, clack-valves, and other forms in which the leaf or -plate of the valve is fastened on one side of the valve seat or opening. - -_Valve-bracket_ is a bracket fitted with a valve. - -_The Valve-chamber_ is where a pump valve or steam valve operates. - -_Valve-cock._—A form of cock or faucet which is closed by dropping of a -valve on its seat. - -_Valve-coupling_ is a pipe coupling containing a valve. - -_Valve-seat_ is the surface upon which a valve rests. - -_Back pressure valves_ are ball or clack valves in a pipe which -instantly assume the seat when a back pressure occurs. They are -illustrated in “6,” Fig. 144. Their name signifies their use—to -maintain a constant back pressure in heating systems. - -_Ball-valve_—a faucet which is opened or closed by means of a ball -floating in the water. It constitutes an automatic arrangement for -keeping the water at a certain level. - -_Bib-cock_—a faucet having a bent-down nozzle. - -_Check-valve_—a valve placed between the feed pipe and the boiler to -prevent the return of the water, etc. - -_Brine-valve_—a valve which is opened to allow water saturated with -salt to escape. In marine service it is “a blow-off valve.” - -_Ball-valve_—a valve occupying a hollow seat. These valves are raised -by the passage of a fluid and descending are closed by gravity. - -_Angle-valve_ is one which forms part of an angle, see Fig. 137. - -_The double-seat valve_ or double-beat valve presents two outlets -for the water. In the Cornish steam engine this is called the -_equilibrium-valve_, because the pressure on the two is very nearly -equalized. - -_Three-way cock_ is one having three positions directing the fluid -in either of three directions. This is illustrated in Fig. 138. The -_three-way valve_ is also illustrated on page 259, Fig. 136. - -_Four-way cock_ is one having two separate passages in the plug and -communicating with four pipes. - -_Gate-valve_—a valve closed by a gate. This is illustrated in Fig. 140. - -_Swing or straight-way valve_—this is shown in Fig. 141, page 261. - -_Throttle-valve._—This is the valve used to admit steam to the engine -and so termed to distinguish it from the main stop-valve located near -the boiler—to throttle means to choke—hence the throttling of the steam. - -_Rotary valves_ are those in which the disc, or plug, or other device -used to close the passage, is made to revolve for opening or closing, -the common stop cock being an illustration. - -_Lifting valves_ are those in which the full cone or stopper is lifted -from the valve seat by pressure from below, the poppet, and safety -valves being examples. - -_Pressure regulator valve_—this is sometimes called a reducing valve -and is illustrated in Figs. 142, 143, on page 262. It is designed to -reduce the pressure from a high point in the boiler to a lower one in a -system of piping, etc. - -Usually the smaller valves, not exceeding 1-1/4 inch in diameter, are -wholly of gun-metal; the larger are commonly made with cast-iron bodies -and gun-metal fittings. The smallest valves, from 1/4 up to 1/2 inch -inclusive, have the disk solid with the spindle, and have an ordinary -stuffing-box with external gland. Valves of 3/4 inch and upwards have -the disk loose from the spindle; up to 3 inch valves the spindles -are screwed to work inside the casing; above that size the screwed -portion is outside the casing. Above the 3-inch size the nozzles of the -cast-iron bodies are generally flanged instead of tapped. - - -STEAM FITTINGS. - -A few of the principal sorts have been illustrated in this work and -still others will be described in the “Index” at the close of the work. - -Fig. 123, page 251, illustrates an _elbow_ with outlet. This is -sometimes spelled with the capital L, and again as an ell. - -Fig. 124 shows a long _nipple_. - -Fig. 125, page 253, exhibits a _bushing_, used to reduce one size pipe -in a line to another. - -Fig. 126 is a _cross tee_. This is frequently spelled with a capital T. - -Fig. 127 is a _plug_—used to stop apertures in plates or pipes. - -Fig. 128, page 254, illustrates a _lock nut_. - -Fig. 129 shows a T, as illustrating the difference between a T and a -cross T, Fig. 126. - -Fig. 130 is a _coupling_. - -Fig. 131, page 255, represents a _reducing coupling_. - -Fig. 132 is an illustration of a pipe _union_. - -Fig. 133 is a plain _elbow_ (see also Fig. 123.) - - -STEAM PIPE AND BOILER COVERINGS. - -This subject relates to the _radiation of heat_, which allows a -reference to the laws of heat and tables of radiating power of various -substances, as set forth on pages 212, 215. - -The importance of a protection of exposed surfaces from radiation of -heat is now undisputed, and many experiments have determined very -closely the relative value of the various non-conducting substances. - -_Table of the_ CONDUCTING POWER _of various substances_. - - ---------------------------+---------- - Substance. |Conducting - | Power. - ---------------------------+---------- - Blotting Paper | .274 - Eiderdown | .314 - Cotton or Wool, any density| .323 - Hemp, Canvas | .418 - Mahogany Dust | .523 - Wood Ashes | .531 - Straw | .563 - Charcoal Powder | .636 - Wood, across fibre | .83 - Cork | 1.15 - Coke, pulverized | 1.29 - India Rubber | 1.37 - Wood, with fibre | 1.40 - Plaster of Paris | 3.86 - Baked Clay | 4.83 - Glass | 6.6 - Stone | 13.68 - ---------------------------+---------- - -By the above table may be judged the comparative value of different -coverings; blotting paper with _its confined air_, standing at one end -of the list, stone at the other. It should be noted that _the less the -conducting power the better protection against radiation_. - -A non-conducting coating for steam pipes, etc., used for many years -with perfect satisfaction, can be prepared by any steam user. It -consists of a mixture of wood sawdust with common starch, used in a -state of thick paste. If the surfaces to be covered are well cleaned -from all trace of grease, the adherence of the paste is perfect for -either cast or wrought iron; and a thickness of 1 inch will produce -the same effect as that of the most costly non-conductors. For copper -pipes there should be used a priming coat or two of potter’s clay, -mixed thin with water and laid on with a brush. The sawdust is sifted -to remove too large pieces, and mixed with very thin starch. A mixture -of two-thirds of wheat starch with one-third of rye starch is the best -for this purpose. It is the common practice to wind string spirally -around the pipes to be treated to secure adhesion for the first coat, -which is about l/5th of an inch thick. When this sets, a second and -a third coat are successfully applied, and so on until the required -thickness is attained. When it is all dry, two or three coats of coal -tar, applied with a brush, protect it from the weather. - -A very efficient covering may be made as follows: 1, wrap the pipe in -asbestos paper—though this may be dispensed with; 2, lay slips of wood -lengthways, from 6 to 12 according to size of pipe—binding them in -position with wire or cord; 3, around the framework thus constructed -wrap roofing paper, fastening it by paste or twine. For flanged pipe, -space may be left for access to the bolts, which space should be filled -with felt. Use tarred paper—or paint the exterior. - -While a very efficient non-conductor, hair or wool felt has the -disadvantage of becoming soon charred from the heat of steam at high -pressure, and sometimes taking fire. The following table, prepared by -Chas. E. Emory, Ph. D., shows _the value_ of various substances, taking -wool felt as a _unit_. - -TABLE OF RELATIVE VALUE OF NON-CONDUCTORS. - - -----------------------+------- - Non-Conductor. | Value. - -----------------------+------- - Wood Felt | 1.000 - Mineral Wool No. 2 | .832 - Do. with tar | .715 - Sawdust | .680 - Mineral Wool No. 1 | .676 - Charcoal | .632 - Pine Wood, across fibre| .553 - Loam, dry and open | .550 - Slaked Lime | .480 - Gas House Carbon | .470 - Asbestos | .363 - Coal Ashes | .345 - Coke in lumps | .277 - Air space, undivided | .136 - -----------------------+------- - - -LINEAR EXPANSION OF STEAM PIPES. - -Wrought iron is said to expand 1/150,000 of an inch for each degree of -heat communicated to it; to make the calculation take the length of the -pipe in inches, multiply it by the number of degrees between the normal -temperature it is required to attain when heated, and divide this by -150,000. Suppose the pipe is 100 feet long, and its temperature zero, -and it is desired to use it to carry steam at 100 pounds pressure—equal -to a temperature of 338 degrees—multiply 100 feet by 12 to reduce it -to inches, and by 338, the difference in temperature; divide this by -150,000, and the result will be 2.7 inches, which would be the amount -of play that would be required, in this instance, in the expansion -joint. - -[Illustration: Figs. 153 and 154.] - -Figs. 153 and 154 show a properly designed arrangement of steam -connections for a battery of boilers. To the nozzles, risers are -attached by means of flanges, and from the upper ends of these risers -pipes are led horizontally backwards into the main steam pipe. In this -horizontal pipe, the stop valves, one to each boiler, are placed. These -valves should have flanged ends as shown, so that they may be easily -removed, if repairs become necessary, without disturbing any other -portion of the piping. Unlike the engraving, the valve C should be -arranged in another position: the stem should, of course, be horizontal -or nearly so, in order that the valve may not trap water. - -By this arrangement it will be seen that the movements of the boilers -and the piping itself are compensated for by the spring of the pipes. -The height of the risers should never be less than three feet, and when -there are eight or ten boilers in one battery, they should be, if room -permits, six to eight feet high, and the horizontal pipes leading to -main steam pipe should be ten or twelve feet or more. - - -THE STEAM LOOP. - -This is an attachment to a steam boiler, designed to return water of -condensation. It invariably consists of three parts, viz.: the “riser,” -the “horizontal” and the “drop leg,” and usually of pipes varying in -size from three-fourth inch to two inches. Each part has its special -and well-defined duties to perform, and their proportions and immediate -relations decide and make up the capacity and strength of the system. -It is, in fact, nothing but a simple return pipe leading from the -source of condensation to the boiler, and, beyond this mere statement, -it is hardly possible to explain it; it has, like the injector and the -pulsometer pump, been called a paradox. - -The range of application of the steam loop practically covers every -requirement for the return of water of condensation. If used in -connection with a steam engine, pump, etc., a separator of any simple -form is connected in the steam pipe as close as possible to the -throttle. From the bottom of the separator the loop is led back to the -boiler, and the circulation maintained by it will dry the steam before -it is admitted to the cylinder. - -There is necessary to its operation a slight fall in temperature at -the head of the loop, which is accompanied by a corresponding fall in -pressure. The water accumulating in the lower end of the loop next to -the separator, as soon as it fills the diameter of pipe, is suddenly -drawn or forced to the horizontal by that difference in pressure. It is -immaterial how far the water has to be taken back, or how high it is -to be lifted. There is one system now in daily operation lifting the -condensed water over thirty-nine feet, and another lifting it over -sixty-three feet. The strength of the system is increased by length -and height, the only limit to its operation being the practicability -of erecting the necessary drop leg, the height of which depends on -difference in pressures. - -[Illustration: Fig. 155.] - -Fig. 155 is an illustration of its application to a radiating coil. -To understand the philosophy of its action, and referring to the -illustration, let us assume that all the valves are open, and full -boiler pressure is freely admitted throughout the steam pipe, coil and -loop. Now, if the pressure were exactly uniform throughout the whole -system, the water in the loop would stand at _a_ on the same level -as the water in the boiler. But, as a matter of fact, the pressure -is not uniform throughout the system, but steadily reduces from the -moment of leaving the dome. This reduction in pressure is due in part -to condensation and in part to friction, and although generally small -is always present in some degree. The pressure may be intentionally -reduced at the valve on the coil, and reduction necessarily results -from condensation within the coil itself. A still further reduction -takes place through the loop, so that the lowest pressure in the whole -system will be found at _a_, the point in the loop furthest from the -boiler, reckoned by the flow of steam. - -Now it is known that water of condensation invariably works towards, -and accumulates in, a “dead end.” This is due to the fact that, as -already shown, the pressure is lower at the “dead end” than at any -other point in the system, and, as a consequence, there is a constant -flow, or sweep, of steam towards the point of least pressure, which -flow continues as long as condensation goes on. This sweep of steam -carries along with it all the water formed by condensation or contained -in the steam, at first in the form of a thin film, swept along the -inner surface of the loop, and afterwards, when the accumulation of -water is sufficient, in the form of small slugs or pistons of water, -which completely fill the pipe at intervals, traveling rapidly towards -the dead end. The action of the steam sweep is vastly more powerful -than is usually supposed, and, of course, operates continuously and -infallibly to deposit the water in the dead end as fast as accumulated. - -In practice, water will speedily be carried over by the loop and -accumulate in the drop leg until it rises to the level _b_, which would -balance the difference in pressure. As the loop will still continue -to bring over water, it follows that as fast as a slug or piston of -water is deposited by the steam on the top of the column at _b, it -overbalances the equilibrium and an equal amount of water is discharged -from the bottom of the column through the check valve into the boiler_. - -The result of the practical operation of many systems of this ingenious -device show advantages as follows: - -1. Return of pure water to the boiler and saving the heat contained in -said water. - -2. Preserving more uniform temperatures, thus avoiding the dangers due -to expansion and contraction. - -3. Prevention of loss from open drains, drips, tanks, etc. - -4. Maintaining higher pressure in long lines of piping, in jackets, -driers, etc. - -5. Enabling engines to start promptly. - -6. Saving steam systems from water, thereby reducing liability to -accident. - - - - -BOILER MAKERS’ TOOLS AND MACHINERY. - - -[Illustration: Fig. 156.] - -Fig. 156 represents a pair of jack screws. These are invaluable devices -for use in boiler-shops, and also in establishments where ponderous -machinery has to be shifted or otherwise handled. - -But few machine tools are used in making steam boilers, and they are -generally as follows: - -1st.—_The Rolls_, operated either by hand levers or power; used for -bending the iron or steel plates into circular form. - -2d.—A wide _power planer_ for trimming the edges of the sheet perfectly -straight and true. - -3d.—_Heavy Shears_ for trimming and cutting the plates. - -4th.—A _Power Punch_ for making the rivet holes. - -5th.—A _Disc_ for making the large holes in the tube sheets to receive -the ends of the tubes. - -6th.—_Rivet heating furnaces_ and frequently _steam riveting machines_. - -The hand tools needed by boiler makers are equally few, consisting of -_riveting hammers_ and hammers for striking the chisels, _tongs_ to -handle hot rivets, _chipping chisels_ used in trimming the edges of -plates, _cape chisels_ for cutting off iron or making holes in the -sheets, _expanders_ to set the tubes, and also _drift pins_ to bring -the punched sheet exactly in line. - -Fig. 157 exhibits an improved pattern of the well-known tool—dudgeon -expander. - -[Illustration: Fig. 157.] - - - - -STEAM. - - -_Steam_ is water in a gaseous state; the gas or vapor of water; it -liquifies under a pressure of 14.7 and temperature of 212° F. - -_Steam_ is a joint production of the intermingling of water and heat. -Water is composed of two gases which have neither color nor taste, and -steam is made up of the same two gases with the addition only of that -mysterious property called heat by which the water becomes greatly -expanded and is rendered invisible. The French have a term for steam -which seems appropriate when they call it water-dust. - -This is what takes place in the formation of steam in a vessel -containing water in free communication with the atmosphere. At first, -a vapor is seen to rise that seems to come from the surface of the -liquid, getting more and more dense as the water becomes hotter. Then -a tremor of the surface is produced, accompanied by a peculiar noise -which has been called _the singing_ of the liquid; and, finally, -bubbles, similar to air bubbles, form in that part of the vessel which -is nearest to the fire, then rise to the surface where they burst, -giving forth fresh vapor. - -The curious fact must be here noted that if water be introduced -into a space entirely void of air, like a vacuum, it vaporizes -instantaneously, no matter how hot or cold, so that of an apparent and -fluid body there only remains an invisible gas like air. - -That steam is _dry_ at high pressure is proved by an experiment which -is very interesting. If a common match head is held in the invisible -portion of the steam jet close to the nozzle, it at once lights, and -the fact seems convincing as to complete dryness, as the faintest -moisture would prevent ignition even at the highest temperature. This -experiment proves dryness of the steam at the point of contact, but if -throttling exists behind the jet, the steam supplied by the boiler may -be in itself wet and dried by wire drawing. - -_Dead steam_ is the same as exhaust steam. - -_Live steam_ is steam which has done no work. - -_Dry steam_ is saturated steam without any admixture of mechanically -suspended water. - -_High-pressure steam_ is commonly understood to be steam used in -high-pressure engines. - -_Low-pressure steam_ is that used at low pressure in condensing -engines, heating apparatus, etc., at 15 lbs. to the inch or under. - -_Saturated steam_ is that in contact with water at the same -temperature; saturated steam is always at its condensing point, which -is always the boiling point of the water, with which it is in contact; -in this it differs from superheated steam. - -_Superheated steam_, also called steam-gas, is steam dried with heat -applied after it has left the boiler. - -_Total heat of steam_ is the same as steam heat. - -_Wet steam_, steam holding water mechanically suspended, the water -being in the form of spray. - -Specific gravity of steam is .625 as compared to air under the same -pressure. - -The properties which make it so valuable to us are: - -1. The ease with which we can condense it. - -2. Its great expansive power. - -3. The small space in which it shrinks when it is condensed either in a -vacuum chamber or the air. - -A cubic inch of water turned into steam at the pressure of the -atmosphere will expand into 1,669 cubic inches. - - - - -WATER HAMMER. - - -The fact that steam piping methods have not kept pace with the demands -of higher pressures and modern practice is evidenced by the increasing -number of accidents from the failure of pipes and fittings. - -There has not been, for the rapid increase of pressure used, a -proportionate increase in strength of flanges, number and size of -bolts used, and more generous provision for expansion and contraction. -Valves and fittings also require greater attention in their design, -construction and manipulation. - -It is well known that the presence of condensed water in pipes is a -source of danger, but little is known of what exactly goes on in the -pipe. We have the incompressible liquid, the expansive gas, and the -tube with a “dead head” or dead end as it is called, or where the end -of the pipe is closed. Seeing that the tube or pipe is capable of -withstanding all the pressure that the steam can give, it is difficult -to account for the tremendous repelling force, which is, undoubtedly, -brought into operation in explosions or ruptures of steam pipes -carrying what are now comparatively low pressures. - -The cause of the bursting is undoubtedly _water hammer or water ram_, -which accompanies large, long steam pipes, filled with condensed water. - -If steam be blown into a large inclined pipe full of water, it will -rise by difference of gravity to the top of the pipe, forming a bubble; -when condensation takes place, the water below the bubble will rush up -to fill the vacuum, _giving a blow directly against the side of the -pipe_. As the water still further recedes the bubble will get larger, -and move farther and farther up the pipe, the blow each time increasing -in intensity, for the reason that the steam has passed a larger mass -of water, which is forced forward by the incoming steam to fill the -vacuum. The maximum effect generally takes place at a “dead end.” - -In fact, under certain conditions, a more forcible blow is struck -when the end of the pipe is open, as, for instance, when a pipe -crowned upward is filled with water, one end being open and the steam -introduced at the other. A bubble will in due time be formed at the top -of the crown, when the water will be forced in by atmospheric pressure -from one end and by steam pressure from the other, and the meeting of -the two columns frequently ruptures the pipe. - -The remedy for this is simple, the pipes must be properly located so as -to drain themselves or be drained by rightly located drip cocks. The -drip should be the other side of the throttle valve, and if steam is -left on over night this valve should be left open enough to drain out -all the water. - - - - -HAZARDS OF THE BOILER ROOM. - - -Where there is great power, there is great danger. - -When the pressure is increased, the danger is increased. - -When the pressure is increased, diligence, care and scrutiny should be -increased. - -During the twelve years between 1879 and 1891 there were recorded 2,159 -boiler explosions; these resulted in the death of 3,123 persons, and in -more or less serious injury to 4,352 others. Besides these there were -innumerable other accidents during the same period, caused by other -means, which emphasizes the gravity of this cautionary “chapter of -accidents.” - -Every boiler constructed of riveted plate and carrying a high head of -steam, holds in constant abeyance, through the strength of a disruptive -shell, a force, more destructive in its escaping violence than burning -gunpowder. To the casual observer there is no evidence of this; and it -is only when a rupture takes place of such a character as to liberate -_on the instant the entire contents of the boiler_ that we get a real -demonstration of the fact. Unfortunately a steam boiler never grows -stronger, but deteriorates with every day’s age and labor, subjected, -as it is, to all sorts of weakening influences; and fractures often -occur, which, if not at once repaired, would speedily reduce the -strength of the boiler to the point of explosion. - -In the case of a boiler we have, first, a vessel of certain strength, -to resist strains; and second, expansive steam and water contained -therein. It must be plain that if the strength of the vessel is -superior to the internal pressure there can be no explosion, and also, -on the contrary, if we allow the pressure to go above the strength of -the vessel, that there must be a rupturing and an explosion, but it -will be in the weakest place of that vessel. - -Experiments by the most eminent men have failed to discover any -mysterious gas formed by boiling water, or by any mixture of air -and water. Boilers have been built for the express purpose of trying -to explode them under various conditions of high and low water, -and nothing in regard to the sudden generation of any gas has been -discovered. Again, disastrous explosions that have occurred have been -of vessels that contained no water, and were not in contact with fire, -flame or heated air, but were supplied by steam some distance away. - -The destructive efforts of the vaporization attendant upon explosions -seem to be due to the subsequent expansion of the steam so formed, -rather than to the intensity of its pressure; low or high steam _alone_ -has very little to do with boiler explosions; nor high or low water -necessarily. - -The one great cause of boiler explosion is the inability of the boiler -to withstand the pressure to which it is subjected at the time, and -this may be brought about by any one of the following causes, viz.: - -1. Bad design, in which the boiler may not be properly strengthened -by stays and braces; deficient water space, preventing the proper -circulation of the water. - -2. Bad workmanship, caused by the punching and riveting being done by -unskilled workmen. - -3. Bad material, blisters, lamination, and the adhesion of sand or -cinders in the rolling of the plate. - -4. By excessive pressure, caused by the recklessness of the engineer, -or by defective steam-gauges or inoperative safety-valves. - -5. Overheating of the plates, caused by shortness of water. When water -is poured on red-hot surfaces it does not touch the surface, but -remains in the spheroidal state at a little distance from it, being -apparently surrounded by an atmosphere of steam. It assumes this state -above 340°; when the temperature falls to about 288° it touches the -surface and commences boiling. - -6. By accumulation of scale, mud, or other deposit, which prevents the -water gaining access to the iron. This causes the seams to leak, the -crown-sheet to bulge or come down. - -One is unable to find any proof that boilers do generally explode at -about starting time, nor is that statement, to the best of information, -founded on any basis of fact, but was first affirmed by parties who had -designed a boiler especially arranged to avoid that imaginary danger. - -No one supposes that inspection will absolutely prevent all explosions; -but rigid inspection will discover defects that might end in explosion. - -Low water is dangerous from the fact that it leaves parts of the boiler -to be overheated and the strength of iron rapidly decreases in such a -case. In fact, an explosion caused by low water might be expected to be -less disastrous than if the water was higher, other conditions being -equal, from the fact of there being less water at a high temperature -ready to flash into steam at the moment of liberation. - -Testing new boilers _under steam pressure_ is both dangerous and -unwise—the hot water expansion test is just as efficient, less costly -and safe in every respect—hence, there is no occasion for a steam test. -A manufacturer was testing a boiler in the way mentioned when a rivet -in a brace blew out and the contents of the boiler rushed out, striking -a man in the face, and parboiling him from head to foot. Another who -was inspecting the boiler, was struck on the head and enveloped in -steam and water; another was also scalded from the shoulders down; -another was injured about the arms; a fifth man was scalded and -severely injured about the back. The apartment was so filled with steam -that the victims could not be rescued until all the damage mentioned -had been done to them. - -Danger from exploding steam pipes is greater than supposed. -An inspector in a pipe works was testing a tube by means of a -double-action hydraulic pump; the pipe suddenly burst with the -pressure of 5,000 pounds to the square inch, and the water striking the -unfortunate man on his face, he was killed on the spot. - -There is a tendency on the part of engineers to trust too implicitly in -their steam gauges. These are usually the only resort for determining -the steam pressure under which the boiler may be working. But the best -gauges are liable to err, and after long use to require a readjustment. -It is fortunate, however, that the error is usually upon the safe side -of indicating more than the actual pressure. - -Any boiler that has been standing idle for a few weeks or months is a -dangerous thing to enter, and no one should attempt it until it has -been thoroughly ventilated by taking off all the man hole and hand-hole -plates and throwing water into it. This is due to the presence of a -gas which is generated from the refuse and mud, or scale, which, to a -greater or less degree, remains in all boilers. Contact with fire is -certain to result in an explosion. Not long since a locomotive was in -a roundhouse, where it had been waiting some weeks for repairs. Some -of the tubes were split and a man was pulling them out. He had only -removed one or two when, putting in his lamp to see what remained, -there was a fearful explosion which shook the shop. There are many -other places which are unsafe to enter when they have been long closed, -such as wells, pits of any kind, and tanks. Precisely what the nature -of the gas is no one seems to know, but it is assuredly settled that a -man who goes into it with a light seldom comes out unharmed. - -The gas most likely to fill idle boilers in cities is sewer gas, that -gets in through the blow-off pipe, which is left open and generally -connects with the sewer; hence, the connection with the sewer by the -blow-off pipes should receive attention. - -Boilers are sometimes unexpectedly emptied of their contents by the -operation of the principle of the syphon; a boiler is so piped that -a column of water may be so formed as to draw out of the boiler its -entire contents. Danger ensues if this is done while the boiler is -being fired. - - -FUEL OIL. - -[Illustration: Oil Valve] - -The long experimental use of petroleum or natural oil as a combustible -has developed but one serious objection to its wide spread and popular -adoption; that objection arises from its liability to ignite and cause -destruction by fire; but - -THE HAZARDS OF FUEL OIL may be remedied by the observance of the -following rules adopted by a certain fire underwriters’ association: - - “Vault to be located so that the oil it contains can burn without - endangering property and have a capacity sufficient to hold twice the - entire quantity of oil the tanks within can contain. - - Location of vault to be left to the approval of the Superintendent of - Surveys. Distance from any property to be regulated by size of tank. - - Vaults to be underground, built of brick, sides and ends to be at - least 16 inches thick and to be made water tight with hydraulic - cement; bottom to be water tight, concrete, dished toward centre, and - inclined to one end so as to drain all overflow or seepage to that - end, said incline to be to the end opposite to that from which the - tank is to be tapped; top to be supported with heavy iron I-beams, - with arches of solid brick sprung from one beam to its neighbors, and - to have at least twelve inches of dirt over the masonry. - - Vault to be accessible by one or more large man-holes, which, when - not in use, are to be kept locked by a large padlock of three or more - tumblers, key to be held by some responsible party. - - A trough must run from one end of the vault to the other, directly - under each tank, and in the same direction as the tank or tanks. - - Tank to be of boiler iron or steel, at least 3/16 inch in thickness, - to be cold riveted, rivets to be not less than 3/8 inch in - diameter and not over 1 inch apart between centres; the entire outer - surface of tank to have two good coats of coal tar or mineral paint - before the tank is placed in position. - - No tank shall be over 8 feet in diameter by 25 in length, nor shall - any vault have over two tanks. - - When tank is set, the bottom of the tank must be 3 inches above the - concrete floor of the vault, and must be in saddles of masonry not - less than twelve inches in thickness, built from the concrete floor - of the vault, said saddles not to be more than 3 feet apart between - centres, and laid in hydraulic cement, with an opening through centre - for drainage. - - Tank must incline 1 inch per 10 feet in length toward the end from - which it is to be tapped, said incline of the tank to be opposite to - the incline at the bottom of the vault. - - The filling pipe, man-hole, telltale or indicator, pump supply - connection, steam connection, overflow pipe and ventilating pipes, - where they connect with tank, must be made petroleum tight by the use - of litharge and glycerine cement. - - Flanges to make tank 3/4 inch in thickness to be riveted on the - inside so as to furnish a satisfactory joint where connections are - made, must be used. - - Filling pipe connection must have gas-tight valve between the tank - and hose coupling, which must be kept closed and locked unless the - tank is being filled. Each tank must have ventilating pipes at least - 1-1/2 inches in diameter, one of which must connect with one end - of the top of the tank and must be in the form of an inverted J, a - union to be placed in pipe just below the bend, within which shall - be placed a diaphragm of fine wire gauze; the other ventilating pipe - must be at the other end of the top of the tank and must be conducted - to the inside of the smoke stack or into the open air at least 10 - feet above the surface, so that all the gases that form in the tank - will be constantly changed. - - Tank must have indicator to show height of oil in tank at all times, - said indicator to be so arranged as to allow no escapement of gases - from tank. All pipes leading from the tank to the pump or place of - burning, must incline toward the tank, and have a fall of at least 2 - feet from bottom of stand pipe to top of storage tank, and must be so - constructed that the feed pipe from stand pipe to burners shall be - entirely above burners, so that no pockets of oil can be formed in - any one of the pipes between the main tank, stand pipe, oil pump or - place of burning. - - The vault shall be air tight as near as possible, and must have - two ventilating pipes of iron of 4 inches diameter, both inlet and - outlet pipes to reach within 6 inches of the bottom of the vault, the - outlet ventilating pipe to rise above surface 8 feet, and the inlet - ventilating pipe to rise above surface 6 feet. - - Syphon to be arranged so as carry out any seepage or leakage into the - vault, and discharge same upon the ground, where its burning would - not endanger surrounding property.” - -_The following are a part of the rules adopted by the German Government -to prevent accidents in mills and factories: they are equally -applicable in all places where steam power is used_: - - “All work on transmissions, especially the cleaning and lubricating - of shafts, bearings and pulleys, as well as the binding, lacing, - shipping and unshipping of belts, must be performed only by men - especially instructed in or charged with such labors. Females and - boys are not permitted to do this work. - - The lacing, binding or packing of belts, if they lie upon either - shafting or pulleys during the operation, must be strictly - prohibited. During the lacing and connecting of belts, strict - attention is to be paid to their removal from revolving parts, either - by hanging them upon a hook fastened to the ceiling, or in any - other practical manner; the same applies to smaller belts which are - occasionally unshipped and run idle. - - While the shafts are in motion they are to be lubricated, or the - lubricating devices examined only when observing the following - rules: (1) The person performing this labor must either do it while - standing upon the floor, or by the use of (2) firmly located - stands on steps, especially constructed for the purpose so as to - afford a good and substantial footing for the workman; (3) firmly - constructed sliding ladders, running on bars; (4) sufficiently high - and strong ladders, especially constructed for this purpose, which - by appropriate safeguards (hooks above or iron points below) afford - security against slipping. - - All shaft bearings are to be provided with automatic lubricating - apparatus. - - Only after the engineer has given the well-understood signal, plainly - audible in the workrooms, is the engine to be started. - - If any work other than lubricating and cleaning of the shafting is to - be performed while the engine is standing idle, the engineer is to - be notified of it, and in what room or place such work is going on, - and he must then allow the engine to remain idle until he has been - informed by proper parties that the work is finished. - - Plainly visible and easy accessible alarm apparatus shall be located - at proper places in the workrooms, to be used in case of accident to - signal to the engineer to stop the engine at once. - - _All projecting wedges, keys, set-screws, nuts, grooves or other - parts of machinery, having sharp edges, shall be substantially - covered._ - - All belts or ropes which pass from the shafting of one story to that - of another shall be guarded by fencing or casing of wood, sheet-iron - or wire netting four feet, 6 inches high. - - The belts passing from shafting in the story underneath and actuating - machinery in the room overhead, thereby passing through the ceiling - must be enclosed with proper casing or netting corresponding in - height from the floor to the construction of the machine. When the - construction of the machine does not admit of the introduction of - casing, then, at least, the opening in the floor through which the - belt or rope passes should be inclosed with a low casing at least - four inches high. - - Fixed shafts, as well as ordinary shafts, pulleys and fly-wheels, - running at a little height above the floor, and being within the - locality where work is performed, shall be securely covered.” - -The most simple and efficient of all substances for fire extinguishment -is sulphur. This, by heat, absorbs oxygen and forms sulphurous acid, -the fumes of which are much heavier than the air. The quantity required -would be small. Besides sulphur, which gives every satisfaction, both -in its effects and from its low cost, we find a similar property in -another active and cheap substance, ammonia. An automatic sulphur -extinguishing apparatus can be made of various forms. - -If night repairs, Sunday, or any other work which requires the use -of artificial light (especially portable lights of any kind) becomes -necessary, more than one man should be employed, one of whom should be -capable of starting the engine or pump instantly in case of fire. - -In guarding against explosion it is conceded that the main reliance is -to have the boiler made strong enough to stand both the regular load -or any unexpected strain caused by the stoppage of the engine; it is -also the tendency of the times to proceed towards higher and higher -figures in steam pressure, until now it is not unfrequent to see 150 -lbs. to the square inch indicated by the gauge; the larger the boiler, -also, the more economically it can be run and this, as in the two cases -before cited, requires extra precautions in building the boiler with -great regard to strength in every part. - -The following rules posted in a certain factory are most excellent for -their directness: - - “Wear close-fitting clothes; have a blouse or jacket to button close - around the waist and body; have sleeves to fit arms closely as far - up as the elbow; never wear a coat around machinery; never approach - a pair of gears or pulleys from the driving side; never attempt to - save time by potting, or trying to pot on any fast-moving belts - without slacking up or stopping entirely to do it. Never allow an - inexperienced person to go through the mills without an attendant; - never allow a woman to go through a mill, no matter how many - attendants, while in motion; never attempt to go through the mill in - the dark, you may forget the exact location of some dangerous object - and seek to avoid it, but it is still there, noiselessly waiting a - chance to wreck you; never allow any dangerous place to go unguarded; - keep your eye open while oiling; never relax your vigilance for an - instant, it may cost you your life. If you feel a gentle tug on your - clothes, grab, and grab quick, anything you can cling to, and don’t - let go till after the clothes do.” - - - - -WATER CIRCULATION. - - -Water consists of an innumerable quantity of extremely minute particles -called molecules. These particles have the property of being able to -glide over, under, and to and from each other almost without resistance -or friction. When water is heated in a boiler the action that takes -place is this: As the heat is applied, the particles nearest the heated -surfaces become expanded or swollen, and are so rendered lighter (bulk -for bulk) than the colder particles, they are therefore compelled to -rise to the highest point in the boiler. - -[Illustration: Fig. 158.] - -This upward action is vividly shown by the illustration on page 242, -and by Fig. 158, where the warmer particles are ascending and the -cooler ones are descending by a process which is endless so long as -heat is applied to the lower part of the containing vessel. - -The cause of circulation is the result of an immutable law of nature -(the law of gravitation), and is so simple that with moderate care -in its manipulation failures in arranging steam heating apparatus are -next to impossible. A very slight experience suffices to show that a -pipe taken from the top of a boiler and given a direct or gradual rise -to the point furthest from the boiler, and then returned and connected -into it at the bottom will, upon the application of heat, cause the -water to circulate. It is not necessary that the water should boil or -even approach boiling point, to cause circulation, as in a properly -constructed apparatus the circulation commences soon after the heat is -applied and immediately the temperature is raised in the boiler. It is -a very common error to suppose that the circulation commences in the -flow or up pipe, whereas it is just the reverse. The circulation is -caused by the water in the return pipe and can be described as a stream -of heated particles flowing up one pipe from the boiler and a stream of -cooler particles flowing down another pipe into the boiler; or it might -be described as a means of automatically transporting heated water from -the lower to the upper parts of a building, and providing a down flow -of cold water to the boiler to be heated in turn. - -Those having in charge the erection of hot-water systems for heating -buildings, will do well to remember that the circulation they expect -depends entirely upon the expansion of particles when heated, and that -they must avoid as much as possible friction, exposure of flow pipes to -very low temperature, and frequent or numerous short bends. - -When properly arranged the action of “the steam loop” is a very good -illustration of the circulation of hot water and steam, the flow is -continuous, rapid and positive. - -NOTE.—When the steam loop is properly connected, the stop valve at the -boiler should always be left open and full pressure maintained in the -steam pipe over night or over Sunday. The loop will keep up a powerful -circulation, returning all water to the boiler as fast as condensed. -On starting up in the morning, it is only necessary to open the -waste cocks and blow out what little water may have condensed in the -cylinders themselves. The throttle may then be opened and the engine -started with the steam as dry as if it had been running continuously. - - - - -CHIMNEYS AND DRAUGHT. - - -Draught, in chimneys, is caused by the difference between the weight of -the air outside and that inside the chimney. This difference in weight -is produced by difference in heat. - -Now, heated air has a strong tendency to rise above cool air and a very -slight difference will cause an upward flow of the heated particles, -and the hotter the air, the brisker the flow. - -As these particles ascend it leaves a space which the cooler air -eagerly hastens to fill; in the boiler furnace, the hot air pushing its -way up the chimney, is replaced through the grate bars with cool, fresh -air. - -It is the mingling of this fresh air with the combustibles that -produces heat, and the power of the draught is absolutely necessary to -the reliable operation of the furnace. - -An excess of draught can be corrected by the use of a damper or even by -the closing of the ash pit doors, but no more unhappy position for an -engineer can be imagined than a deficiency of draught. - -This lack is produced by, 1st, too little area in the chimney flue; 2d, -by too low a chimney; 3d, by obstructions to the flow of the gases; -4th, by the overtopping of the chimney by adjacent buildings, hills or -tree tops. There are other causes of failure which practice develops; -hence, the draught of a new chimney is very often an uncertain thing -until every-day trial demonstrates its action. - -The draught of steam boilers and other furnaces should be regulated -below the grate and not in the chimney. The ash pit door should be -capable of being closed air tight, and the damper in the chimney should -be kept wide open at all times unless it is absolutely necessary to -have the area of the chimney reduced in order to prevent the gases from -escaping too fast to make steam. - -When two flues enter a larger one at right angles to it, opposite -each other, as is frequently the case where there is a large number -of boilers in a battery, and the chimney is placed near the center of -the battery, the main flue should always have a division plate in its -center between the two entering flues to give direction to the incoming -currents of gases, and prevent their “butting,” as it may be termed. -The same thing should always be done where two horizontal flues enter a -chimney at the same height at opposite sides. - -In stationary boilers the chimney area should be one-fifth greater than -the combined area of all the tubes or flues. - -For marine boilers the rule is to allow fourteen square inches of -chimney area for each nominal horse power. - -The draught of a chimney is usually measured in inches of water. The -arrangement most commonly made use of for this purpose consists of a -U-shaped glass tube connected by rubber tubing, iron pipe, or other -arrangement, with some part of the chimney in such a way that the -draught will produce a difference of level of water in the two legs of -the bent glass tube. - -The “Locomotive” suggests that _the unit for chimney construction_ -should be a flue 81 feet high above the level of the grates, having -an area equal to the collective area of the tubes of all the boilers -leading to it, the boilers being of the ordinary horizontal return -tubular type, having about 1 square foot of heating surface to 45 -square feet of heating surface. - -Note the above conditions, and, in case of changing the above -proportions, it should be observed that the draught power of chimneys -is proportional to the square root of the height, so we may reduce -its area below the collective area of the boiler tubes _in the same -proportion that the square root of its height exceeds the square root -of 81_. - -For example, suppose we have to design a chimney for ten boilers, 66 -in. in diameter, each having 72 tubes, 3-1/2 in. in diameter, what -would be its proportion? - -The collective area of the 720 3-1/2-in. tubes would be 6,017 square -inches, and if the chimney is to be but 81 feet high, it should have -this area, which would require a flue 6 ft. 5-1/2 in. square. - -But, suppose, for some reason, it is decided to have a chimney 150 feet -in height, instead of 81 feet. The square root of 150 is 12-1/4; the -square root of 81 is 9; and we reduce the area of the chimney by the -following proportion: 12.25:9 = 6,017:4,420 square inches, which would -be the proper area, and would call for a chimney 5 ft. 6 in. square, -and similarly if any other height were decided upon. - - - - -PLUMBING. - - -[Illustration: Pipe Trap] - -[Illustration: P Trap] - -The art of working in lead is older than the pyramids. For thousands -of years hydraulics and plumbing as an occupation engaged the -principal attention of engineers. King David used lead pipe, so did -Archimedes; the terraces and gardens of Babylon were supplied with -water through leaden pipes. Steam fitting, with galvanized pipe and -an elaborate system of connections and devices is a new department of -mechanism—almost of the present generation—and at first sight would -seem able soon to supercede lead piping of all kinds, but it is safe to -say that nothing can ever take the place of lead, for this admirable -metal can be made to answer where no other material can be worked; for -instance, lead pipe can be made to conform to any angle or obstruction -where no other system of piping will. Hence, plumbing as a useful and -ornamental art will never go out of date, and engineers of every branch -will do well to study its principles and methods so as to meet the -ever-recurring and perplexing questions connected with sewerage, water -supply, etc. - -[Illustration: S Trap] - -Every engineer should at least know how 1, _to join lead pipe_—to make -a “wipe joint,”—as in a hundred emergencies this knowledge will be of -worth. 2, how to make a temporary stopping of leaks; 3, how to bend -pipe with sand or springs; 4, how to “back air pipes” from sinks; 5, -how to use force pumps; 6, how to arrange the circulating pipes in -hot-water boilers; 7, how to make solder; 8, how to repair valves, -etc., etc. - -PIPING AND DRAINAGE. - -The three illustrations on page 298 are designed to represent traps set -in lead pipe and show vividly the difference between this material and -iron piping. - -[Illustration: Fig. 159.] - -Lead is one of the elementary substances of which the world is formed; -it ranks with gold, silver, tin, etc., in being an unmixed metal. -It melts at about 617° Fahrenheit, and is, bulk for bulk, 11-4/10 -heavier than water (gold being 17-5/10 heavier and wrought iron 7-7/10 -heavier). The tenacity of lead is extremely low, a wire 1/18th of an -inch breaks with a weight of 28 lbs.; in comparison, its tenacity is -only one-twentieth that of iron; it is so soft that it may be scratched -with the thumb nail. If a very strong heat is applied lead boils and -evaporates; it transmits heat very slowly; of seven common metals it is -the worst conductor, therefore it is good for hot water pipes. Mixed -with a sufficient quantity of quicksilver it remains liquid. - -An advantage to be found in the use of lead is its durability and -comparative freedom from repairs. In London, soil and drain water pipes -which have been fixed 300 to 500 years are as good now as the day they -were first made—while iron pipe cannot be expected to last over 10 or -20 years or 30 at the utmost. - -Fig. 159 represents the general system of house piping and drainage -applicable also to shops, public buildings, etc. A exhibits the drain -or sewer. A-C represents the sewer connection, so called with a running -trap, B. “C” at the end of the lower pipe exhibits a soil pipe elbow, -with hand hole for cleaning out closed by a screw plug. This drain -should have a regular fall or inclination and this elbow provides for -that. C-D shows the rain water leader (conductor). - -E and F is a soil pipe 3, 4, 5, or 6 inches in diameter. Note, pipes -draining water closets are called “soil pipes”; those draining other -fixtures “waste pipes.” N and O represent water-closet flanges; F and -H are roof connections; L exhibits double and single =Y= branches to -receive waste-pipes from baths, bowls, or sinks. The plumber makes this -connection, always trapping the lead waste-pipe and then soldering it -to a _brass_ nipple. - - -LEAD PIPE JOINTS. - -[Illustration: Fig. 160.] - -It has been remarked that after learning how to make “a wipe joint,” -everything is easy relating to the plumber’s trade; hence, the -importance of the following directions. - -To learn the art, previous practice with short pieces of pipe is -recommended. This trial piece can be clamped as shown in Fig. 160 and -used over and over until practice has been had. - -There are many names for the process of lead joint-making, such as the -flow-joint, the ribbon joint, the blown joint, the astragal joint, -etc., to express the different positions and uses for which they are -needed, but in the main they are made as follows: - -1. The lead pipe to be joined is sawn square off with the proper -toothed saw—attention being paid to making the end absolutely true, -across the pipe. - -2. One end of the pipe to be joined is first opened by driving in a -wooden wedge, shaped like a plumb-bob, called the “turn pin.” Care -should be exercised at this time not to split the end, 1/4 inch opening -is usually enough, which leaves the pipe as shown at D, Fig. 161. Now, -clean the internal part of the joint all around the part required for -soldering—this cleaning can be done with the plumber’s shave hook or -with a pocket knife. To complete this preparation “touch” the part with -grease from a tallow candle. - -3. Next is the preparation of the male part of the joint. This must be -rasp-filed down to fit the enlarged opening. It is important to have a -good fit throughout; hence, inside the enlarged opening must be also -rasp-filed and the two surfaces to come nicely together before the -solder is applied. - -4. At this stage a paste called “plumber’s soil” must be applied -outside 3 inches from the end of each piece of pipe; this is shown -by the line E F in Fig. 161, also at A B, Fig. 160; the line of the -soiling should be very even and true in order to assure a workmanlike -job and the soiling put on as before stated, _3 to 5 inches beyond the -solder line on each side_. - -As the melting point of lead is 612 degrees or thereabouts, it is -necessary to have solder melt at a lower temperature, and that made -under the rule given will melt at 440 to 475 degrees. - -No tool to a plumber is more important than the cloth used in joint -making. To make it, take a piece of new mole skin or fustian, of -moderate thickness, 12 inches long by 9 inches wide, fold it up one -side 4 inches; then 4 inches again, and again 4 inches; then fold it -in the middle, which will make your cloth 4 × 4-1/2 inches, and of 6 -thickness. After this is done, sew up the ragged ends to keep it from -opening. Then pour a little hot tallow on one side and the cloth is -ready for use. In Fig. 160-a is shown, H, a hand holding the cloth C in -the process of “wiping the joint,” which will now be described. - -First place a small piece of paper under the joint to catch the surplus -solder D and begin soldering as follows: Take the felt F in the right -hand and with it hold the ladle three parts full of solder. To see that -it is not too hot hold your hand within 2 inches or so of the solder; -if it quickly burns your hand it is too hot; if you can only just hold -your hand this distance, use it; but if you cannot feel the heat, the -solder is too cold. - -When you begin to pour your solder upon the joint do it very lightly -and not too much at a time in one place, but keep the ladle moving -backward and forward, pouring from E to J, first on one side of the -joint to the other and from end to end. - -Pour also an inch or two up the soiling, as shown at E to make the pipe -of proper temperature, _i.e._, to the same heat as the solder. The -further, in reason, the heat is run or taken along the pipe, the better -the chance of making the joint. - -[Illustration: Fig. 160-a.] - -Keep pouring and with the left hand hold the cloth C to catch the -solder and also cause the same to tin the lower side of the pipe and to -keep the solder from dropping down. This cloth, so important in joint -making is elsewhere described. By the process of steady pouring the -solder now becomes nice and soft and begins to feel shaped, firm and -bulky. - -When in this shape and in a semi-fluid condition quickly put the ladle -down, and instantly with the left hand shape one side of the joint -always beginning at the outsides, or at that part next the soiling; -then take the cloth in the right hand and do the other side, _finishing -on the top_; a light run of the cloth all round the joint will, if the -solder has not set and you have been quick with your work, give the -appearance of a turned joint. After a little practice the joint may be -made without changing the cloth from one hand to the other. - -_The secret of joint making is getting the lead to the heat of the -solder and in roughly shaping the solder, while in the semi-fluid -state._ - -Good mechanical fitting is the result of two things—good judgment and a -delicate sense of touch. - - -REPAIRING PIPES WITH PUTTY JOINTS. - -[Illustration: Fig. 161.] - -First get the pipe _thoroughly dried_, and with some quick drying -gold size paint the part to be repaired; then get some white lead and -stiffen it with some powdered red lead, so as to make it a hardish -putty, place a thin layer of this, say 3/8th inch to 1/2 inch in -thickness, over the bursted part of the pipe, and with some good strong -calico, painted with the gold size, neatly wrap the red lead to the -pipe, using 3 or 4 thicknesses of the painted calico; then with some -twine begin at one end, laying the twine in several layers in rotation -until it has, like the calico, several thicknesses. - -If properly done this will be strong enough to withstand any ordinary -pressure on the pipes and if more is required the putty can be made -from dry red lead and gold size. In making all white and red lead -joints, first, see that the parts are thoroughly dry; second, see that -the parts are not dirty with rust, &c.; next, well paint the parts with -good, stiff paint before putting the putty on to form the joint. - - -BENDING LEAD PIPE. - -If any ordinary piece of light lead pipe 1-1/2 inches in diameter is -taken and pulled or bent sharply around it will crimple or crinkle at -the throat; the larger and thinner the pipe the more it will become -distorted. - -There are many methods of making these bends in lead pipe, some with -dummies, others with bolts, balls, etc., others cut the bends at the -back, at the throat, or the two sides of the bend. - -For small pipes, such as 1/2 to 1 inch and extra heavy, they may be -pulled round without trouble or danger, but for a little larger size -SAND BENDING is largely practiced as follows: - -Take the length of pipe, say 5 feet, fill and well ram it with sand 2 -feet up, then have ready a metal pot of very hot sand to fill the pipe -1 foot up, next fill the pipe up with more cold sand, ramming it as -firmly as possible, stop the end and pull round the pipe, at the same -time hammering quickly working the lead from the throat towards the -back, which can be done if properly worked. N. B.—Care must be used not -to reduce or enlarge the size of the bore at the bend. - -BENDING WITH WATER.—It is a well-known fact that for such work, water -is incompressible, but may be turned or twisted about for any shape -provided it is enclosed in a solid case. To make the bend—the end of -the pipe is stopped and a stop cock soldered into the other end; take -the pipe at the end and pull it around, being careful that the water -does not cool and shrink, and hammering quickly to take out the crinkle. - -BENDING WITH BALLS.—This method is practiced with small pipe and also -to take “dints” out in case of sand and water bending when a ball is -sent through. Method: suppose the pipe to be two inches, then a ball is -required 1/16 in. less than the pipe, so that it will run through the -pipe freely. Now pull the pipe round until it just begins to flatten, -put the ball into the pipe and with some short pieces of wood, say 2 -in. long by 1-1/2 in. in diam., force the ball through the dented part -of the pipe. The ball will run through all the easier if “touched” over -with a candle end. Care must be used in forcing the ball back and forth -not to drive it through the bend. - - -TABLE.—WEIGHT OF SHEET LEAD. - - ---------+-----+-----+-----+-----+-----+-----+-----+-----+----- - Inside | 3/8 | 1/2 | 5/8 | 3/4 | 1 |1-1/4|1-1/2|1-3/4| 2 - Diameter | | | | | | | | | - ---------+-----+-----+-----+-----+-----+-----+-----+-----+----- - | weight per foot, lbs., oz. - AAA, | 2- 8| 3- 0| 3- 8| 4-12| 6- 0| -- | -- | -- | -- - AA, | 1- 8| 2- 0| 2-12| 3-12| 4-12| 6- 0| 8- 0| 8- 8| 9- 0 - A, | 1- 4| 1-12| 2- 8| 3- 0| 4- 3| 4-12| 6- 8| 6- 8| 7- 0 - B, | 1- 4| 1- 4| 2- 0| 2- 4| 3- 4| 3-12| 5- 0| 5- 0| 6- 0 - C, | -10| 1- 0| 1- 8| 1-12| 2- 8| 3- 0| 4- 4| 4- 0| 4-12 - D, | - 7| -12| 1- 0| 1- 4| 2- 0| 2- 8| 3- 8| -- | -- - E, | -- | - 9| -12| 1- 0| 1-10| 2- 0| 3- 0| -- | -- - - Sheet lead is not the same weight, - bulk for bulk, owing to difference - in organic formation, but a cubic - foot may be said to weigh 709 lbs. - A square foot 1″ thick, 59 „ - „ „ „ 1/8″ „ 7-1/2 „ - „ „ „ 1/10″ „ 6 „ - „ „ „ 1/12″ „ 5 „ - „ „ „ 1/15″ „ 4 „ - „ „ „ 1/20″ „ 3 „ - -Sheet lead is sometimes made as thin as writing paper. - - -PLUMBER’S SOLDER. - -_Rule for making._—Take 100 lbs. good old lead or lead cuttings, run it -down thoroughly, stir it up and take off all dirt or dross: then take -50 lbs. pure tin, let this run down, and when nearly all is melted and -is a little cooler throw in 1/2 lb. of black rosin, and well stir the -lot up. Last bring up the heat to 600 degrees which may be known by the -burning of a bit of newspaper put in the pot. The solder is now hot -enough and should be well stirred and then run into moulds. - - -PLUMBER’S TOOLS. - -The processes of lead working are executed by manual dexterity acquired -by long practice, and to do the work properly requires many special -tools. Some of these are used in common with other departments of -mechanics, but are none the less necessary in lead working. - -We present cuts of the principal tools used, some of which are -self-explaining, and some are named with further description of -particular use. - -[Illustration: Fig. 162.] - -Fig. 162 represents one form of the plumber’s tap borer or reamer used -for making and enlarging holes in pipe. - -[Illustration: Fig. 163.] - -Fig. 163 represents plumber’s snips. - -[Illustration: Fig. 164.] - -Fig. 164 is the well-known and always useful ladle. - -[Illustration: Fig. 165.] - -Fig. 165 is the round nose pein hammer, used in plumber’s work to open -the inside pipe before jointing. - -[Illustration: Fig. 166.] - -Fig. 166 is the plumb bob. The same cut will also convey an idea of the -wooden instrument used to force open the pipe before jointing, _i.e._, -“the turn pin.” - -[Illustration: Fig. 167.] - -Fig. 167 represents “the round nose chisel.” - -[Illustration: Fig. 168.] - -Fig. 168 is the “wood chisel” used in cutting away wood work. - -[Illustration: Fig. 169.] - -Fig. 169 is the well-known “cape chisel.” - -[Illustration: Fig. 170.] - -Fig. 170 is the half round chisel. - -[Illustration: Fig. 171.] - -Fig. 171 is the equally well-known “flat cold chisel.” - -[Illustration: Fig. 172.] - -Fig. 172 is the “diamond point chisel.” - -[Illustration: Fig. 173.] - -Fig. 173 shows a rivet set for small work connected with plumbing and -sheet metal work. - -[Illustration: Fig. 174.] - -Fig. 174 exhibits the plumber’s torch; this is also used by engineers -to explore interiors of boilers, chimney flues, and other dark places -about the steam plant. - -Fig. 175 is a compass saw. - -Fig. 176 is a double-edged plumber’s saw. - -Fig. 177 is a spirit level. - -Fig. 178 is a looking-glass used in making underhand joints and in many -useful ways about a steam plant. - -[Illustration: Fig. 175.] - -[Illustration: Fig. 176.] - -[Illustration: Fig. 177.] - -[Illustration: Fig. 178.] - -[Illustration: Fig. 179.] - -Fig. 179 is a caulking tool. - -[Illustration: Fig. 180.] - -Fig. 180 is a gasket chisel. - -[Illustration: Fig. 181.] - -Fig. 181 is a soldering tool known among plumbers as “a copper pointed -bolt.” - -[Illustration: Fig. 182.] - -Fig. 182 is a copper-pointed bolt, flat. - -[Illustration: Fig. 183.] - -Fig. 183 represents a hanger, for suspending iron and lead pipe; its -excellence consists in enabling pipes to be raised or lowered after -being hung without taking the hanger apart. - - - - -USEFUL TABLES OF WEIGHTS OF IRON AND COMPARISONS OF GAUGES. - -Weight of a Superficial Foot of Plate and Sheet Iron. - - +------------------------------------------------------+ - | PLATE IRON. | - +----------------------------+-------------------------+ - | | Weight | - | Thickness. | per | - | | square foot. | - +----------------------------+-------------------------+ - | INCHES. | POUNDS. | - +----------------------------+-------------------------+ - | 1/16 in. | 2-1/2 | - | 1/8 „ | 5 | - | 3/16 „ | 7-1/2 | - | 1/4 „ | 10 | - | 5/16 „ | 12-1/2 | - | 3/8 „ | 15 | - | 7/16 „ | 17-1/2 | - | 1/2 „ | 20 | - | 9/16 „ | 22-1/2 | - | 5/8 „ | 25 | - | 11/16 „ | 27-1/2 | - | 3/4 „ | 30 | - | 13/16 „ | 32-1/2 | - | 7/8 „ | 35 | - | 15/16 „ | 37-1/2 | - | 1 „ | 40 | - +----------------------------+-------------------------+ - | SHEET IRON. | - +----------------------------+-------------------------+ - | UNITED STATES STANDARD GAUGE. | - | Adopted by Congress, to take effect July 1st, 1893. | - +---------+----------+--------------+------------------+ - | NUMBER | 1000’S | WEIGHT | NEAREST | - | OF | OF | PER | FRACTION OF | - | GAUGE. | an Inch. | square foot. | an inch. | - | | | OUNCES | | - +---------+----------+--------------+------------------+ - | No. 1 | .281 | 180 oz. | 9/32 in. | - | „ 2 | .265 | 170 „ | 17/64 „ | - | „ 3 | .250 | 160 „ | 1/4 „ | - | „ 4 | .234 | 150 „ | 15/64 „ | - | „ 5 | .218 | 140 „ | 7/32 „ | - | „ 6 | .203 | 130 „ | 13/64 „ | - | „ 7 | .187 | 120 „ | 3/16 „ | - | „ 8 | .171 | 110 „ | 11/64 „ | - | „ 9 | .156 | 100 „ | 5/32 „ | - | „ 10 | .140 | 90 „ | 9/64 „ | - | „ 11 | .125 | 80 „ | 1/8 „ | - | „ 12 | .109 | 70 „ | 7/64 „ | - | „ 13 | .093 | 60 „ | 3/32 „ | - | „ 14 | .078 | 50 „ | 5/64 „ | - | „ 15 | .070 | 45 „ | 9/128 „ | - | „ 16 | .062 | 40 „ | 1/16 „ | - | „ 17 | .056 | 36 „ | 9/160 „ | - | „ 18 | .050 | 32 „ | 1/20 „ | - | „ 19 | .043 | 28 „ | 7/160 „ | - | „ 20 | .037 | 24 „ | 3/80 „ | - | „ 21 | .034 | 22 „ | 11/320 „ | - | „ 22 | .031 | 20 „ | 1/32 „ | - | „ 23 | .028 | 18 „ | 9/320 „ | - | „ 24 | .025 | 16 „ | 1/40 „ | - | „ 25 | .021 | 14 „ | 7/320 „ | - | „ 26 | .018 | 12 „ | 3/160 „ | - | „ 27 | .017 | 11 „ | 11/640 „ | - | „ 28 | .015 | 10 „ | 1/64 „ | - | „ 29 | .014 | 9 „ | 9/640 „ | - | „ 30 | .012 | 8 „ | 1/80 „ | - +---------+----------+--------------+------------------+ - -Weight of One Foot of Round Iron. - - +----------------+---------------------+ - | SIZE. | Weight pr. Foot. | - +----------------+---------------------+ - | | LBS. | - +----------------+---------------------+ - | 1/8 in. | .041 | - | 3/16 „ | .092 | - | 1/4 „ | .164 | - | 5/16 „ | .256 | - | 3/8 „ | .368 | - | 7/16 „ | .501 | - | 1/2 „ | .654 | - | 9/16 „ | .828 | - | 5/8 „ | 1.02 | - | 11/16 „ | 1.24 | - | 3/4 „ | 1.47 | - | 13/16 „ | 1.73 | - | 7/8 „ | 2.00 | - | 15/16 „ | 2.30 | - | 1 „ | 2.62 | - | 1-1/16 „ | 2.95 | - | 1-1/8 „ | 3.31 | - | 1-3/16 „ | 3.69 | - | 1-1/4 „ | 4.09 | - | 1-5/16 „ | 4.51 | - | 1-3/8 „ | 4.95 | - | 1-7/16 „ | 5.41 | - | 1-1/2 „ | 5.89 | - | 1-9/16 „ | 6.39 | - | 1-5/8 „ | 6.91 | - | 1-11/16 „ | 7.45 | - | 1-3/4 „ | 8.02 | - | 1-13/16 „ | 8.60 | - | 1-7/8 „ | 9.20 | - | 1-15/16 „ | 9.83 | - | 2 „ | 10.47 | - | 2-1/8 „ | 11.82 | - | 2-1/4 „ | 13.25 | - | 2-3/8 „ | 14.77 | - | 2-1/2 „ | 16.36 | - | 2-3/8 „ | 18.04 | - | 2-3/4 „ | 19.80 | - | 2-7/8 „ | 21.64 | - | 3 „ | 23.56 | - | 3-1/8 „ | 25.57 | - | 3-1/4 „ | 27.65 | - | 3-3/8 „ | 29.82 | - | 3-1/2 „ | 32.07 | - | 3-5/8 „ | 34.40 | - | 3-3/4 „ | 36.82 | - | 3-7/8 „ | 39.31 | - | 4 „ | 41.89 | - | 4-1/8 „ | 44.55 | - | 4-1/4 „ | 47.29 | - | 4-3/8 „ | 50.11 | - | 4-1/2 „ | 53.01 | - | 4-5/8 „ | 56.00 | - | 4-3/4 „ | 59.07 | - | 4-7/8 „ | 62.22 | - | 5 „ | 65.45 | - | 5-1/8 „ | 68.76 | - | 5-1/4 „ | 72.16 | - | 5-3/8 „ | 75.64 | - | 5-1/2 „ | 79.19 | - | 5-5/8 „ | 82.83 | - | 5-3/4 „ | 86.56 | - | 5-7/8 „ | 90.36 | - | 6 „ | 94.25 | - +----------------+---------------------+ - -Weight of One Foot of Square Iron. - - +----------------+---------------------+ - | SIZE. | Weight pr. Foot. | - +----------------+---------------------+ - | | LBS. | - +----------------+---------------------+ - | 1/8 in. | .052 | - | 3/16 „ | .117 | - | 1/4 „ | .208 | - | 5/16 „ | .326 | - | 3/8 „ | .469 | - | 7/16 „ | .638 | - | 1/2 „ | .833 | - | 9/16 „ | 1.06 | - | 5/8 „ | 1.30 | - | 11/16 „ | 1.58 | - | 3/4 „ | 1.87 | - | 13/16 „ | 2.20 | - | 7/8 „ | 2.55 | - | 15/16 „ | 2.93 | - | 1 „ | 3.33 | - | 1-1/16 „ | 3.76 | - | 1-1/8 „ | 4.22 | - | 1-3/16 „ | 4.70 | - | 1-1/4 „ | 5.21 | - | 1-5/16 „ | 5.74 | - | 1-3/8 „ | 6.30 | - | 1-7/16 „ | 6.89 | - | 1-1/2 „ | 7.50 | - | 1-9/16 „ | 8.14 | - | 1-5/8 „ | 8.80 | - | 1-11/16 „ | 9.49 | - | 1-3/4 „ | 10.21 | - | 1-13/16 „ | 10.95 | - | 1-7/8 „ | 11.72 | - | 1-15/16 „ | 12.51 | - | 2 „ | 13.33 | - | 2-1/8 „ | 15.05 | - | 2-1/4 „ | 16.88 | - | 2-3/8 „ | 18.80 | - | 2-1/2 „ | 20.83 | - | 2-3/8 „ | 22.97 | - | 2-3/4 „ | 25.21 | - | 2-7/8 „ | 27.55 | - | 3 „ | 30.00 | - | 3-1/8 „ | 32.55 | - | 3-1/4 „ | 35.21 | - | 3-3/8 „ | 37.97 | - | 3-1/2 „ | 40.83 | - | 3-5/8 „ | 43.80 | - | 3-3/4 „ | 46.88 | - | 3-7/8 „ | 50.05 | - | 4 „ | 53.33 | - | 4-1/8 „ | 56.72 | - | 4-1/4 „ | 60.21 | - | 4-3/8 „ | 63.80 | - | 4-1/2 „ | 67.50 | - | 4-5/8 „ | 71.30 | - | 4-3/4 „ | 75.21 | - | 4-7/8 „ | 79.22 | - | 5 „ | 83.33 | - | 5-1/8 „ | 87.55 | - | 5-1/4 „ | 91.88 | - | 5-3/8 „ | 96.30 | - | 5-1/2 „ | 100.80 | - | 5-5/8 „ | 105.50 | - | 5-3/4 „ | 110.20 | - | 5-7/8 „ | 115.10 | - | 6 „ | 120.00 | - -Weight per Running Foot of Cast Steel. - - -------------+------+--------------+------ - SIZE. | LBS. | SIZE. | LBS. - -------------+------+--------------+------ - 1/4 in. Sq.| .213| 1/4 in. Rd. | .167 - 1/2 „ „ | .855| 1/2 „ „ | .669 - 3/4 „ „ | 1.91 | 3/4 „ „ | 1.50 - 1 „ „ | 3.40 |1 „ „ | 2.67 - 1-1/4 „ „ | 5.32 |1-1/4 „ „ | 4.18 - 1-1/2 „ „ | 7.67 |1-1/2 „ „ | 6.02 - 2 „ „ |13.63 |2 „ „ |10.71 - -------------+------+--------------+------ - 1 × 1/4 | .852| 1/2 in. Oct.| .745 - 1-1/8 × 3/8 | 1.43 | 5/8 „ „ | 1.16 - 1-1/4 × 1/2 | 2.13 | 3/4 „ „ | 1.67 - 1-1/2 × 5/8 | 3.19 | 7/8 „ „ | 2.28 - 1-3/4 × 3/4 | 4.46 |1 „ „ | 2.98 - 2 × 1/2 | 3.40 |1-1/8 „ „ | 3.77 - „ × 5/8 | 4.25 |1-1/4 „ „ | 4.65 - -Comparison of Principal Gauges in use. - - -------+-------------------+-------------------+------------------- - | UNITED STATES | STUBBS’ | BROWN & SHARP. - | STANDARD. | BIRMINGHAM. | - +--------+----------+--------+----------+--------+---------- - Number.| | Pounds | | Pounds | | Pounds - | 1000’s |per square| 1000’s |per square| 1000’s |per square - | of | foot. | of | foot. | of | foot. - |an inch.| |an inch.| |an inch.| - | | IRON. | | IRON. | | IRON. - -------+--------+----------+--------+----------+--------+---------- - No. 1 | .281 | 11.25 | .300 | 12.04 | .289 | 11.61 - „ 2 | .265 | 10.62 | .284 | 11.40 | .257 | 10.34 - „ 3 | .250 | 10. | .259 | 10.39 | .229 | 9.21 - „ 4 | .234 | 9.37 | .238 | 9.55 | .204 | 8.20 - „ 5 | .218 | 8.75 | .220 | 8.83 | .181 | 7.30 - „ 6 | .203 | 8.12 | .203 | 8.15 | .162 | 6.50 - „ 7 | .187 | 7.50 | .180 | 7.22 | .144 | 5.79 - „ 8 | .171 | 6.87 | .165 | 6.62 | .128 | 5.16 - „ 9 | .156 | 6.25 | .148 | 5.94 | .114 | 4.59 - „ 10 | .140 | 5.62 | .134 | 6.38 | .102 | 4.09 - „ 11 | .125 | 5.00 | .120 | 4.82 | .091 | 3.64 - „ 12 | .109 | 4.37 | .109 | 4.37 | .080 | 3.24 - „ 13 | .093 | 3.75 | .095 | 3.81 | .072 | 2.89 - „ 14 | .078 | 3.12 | .083 | 3.33 | .064 | 2.57 - „ 15 | .070 | 2.81 | .072 | 2.89 | .057 | 2.29 - „ 16 | .062 | 2.50 | .065 | 2.61 | .050 | 2.04 - „ 17 | .056 | 2.25 | .058 | 2.33 | .045 | 1.82 - „ 18 | .050 | 2.00 | .049 | 1.97 | .040 | 1.62 - „ 19 | .043 | 1.75 | .042 | 1.69 | .036 | 1.44 - „ 20 | .037 | 1.50 | .035 | 1.40 | .032 | 1.28 - „ 21 | .034 | 1.37 | .032 | 1.28 | .028 | 1.14 - „ 22 | .031 | 1.25 | .028 | 1.12 | .025 | 1.02 - „ 23 | .028 | 1.12 | .025 | 1.00 | .022 | .90 - „ 24 | .025 | 1.00 | .022 | .88 | .020 | .80 - „ 25 | .021 | .87 | .020 | .80 | .018 | .72 - „ 26 | .018 | .75 | .018 | .72 | .016 | .64 - „ 27 | .017 | .68 | .016 | .64 | .014 | .57 - „ 28 | .015 | .62 | .014 | .56 | .012 | .50 - „ 29 | .014 | .56 | .013 | .52 | .011 | .45 - „ 30 | .012 | .50 | .012 | .48 | .010 | .40 - - - - -NOISELESS WATER HEATER. - - -This device is very effective for heating water in open or closed tanks -by direct steam pressure without noise. The heater consists of an -outward and upward discharging steam nozzle, covered by a shield which -has numerous openings for the admission of water so that the discharge -jet takes the form of an inverted cone, discharging upwards. - -[Illustration: Fig. 184.] - -A small pipe admits air to the steam jet, and by mixing therewith -prevents a collapse of the steam bubbles, and the noise, which is such -a great objection to heating by direct steam in the old way. A valve -or cock on the small air pipe regulates the opening as may appear most -desirable. - -Exhaust steam can by the same method be disposed of under water without -noise. - - - - -ACCIDENTS AND EMERGENCIES. - - -Few subjects can more usefully employ the attention and study of -engineers than the proper treatment and first remedies made necessary -by the peculiar and distressing accidents to which persons are liable -who are employed in or around a steam plant. - -These and many other things of a like nature are likely to call for a -cool head, a steady hand and some practical knowledge of what is to be -done. - -[Illustration: Fig. 185.] - -In the first moments of sudden disaster, of any kind, the thoroughly -trained engineer is nearly always found, in the confusion incident to -such a time, to be the one most competent to advise and direct the -efforts made to avert the danger to life limb or property, and to -remedy the worst after effects. - -_To fulfil this responsibility is worth much previous preparation_, -so that the best things under the circumstances may be done quickly -and efficiently. To this end the following advice is given relating to -the most common accidents which are likely to happen, in spite of the -utmost exercise of care and prudence. - - -=_Burns and Scalds._=—_Burns_ are produced by heated solids or by -flames of some combustible substance; _scalds_ are produced by steam or -a heated liquid. The severity of the accident depends mainly, 1, on the -intensity of the heat of the burning body, together with, 2, the extent -of surface, and, 3, the vitality of the parts involved in the injury, -thus: a person may have a finger burned off with less danger to life -than an extensive scald of his back. - -The immediate effect of scalds is generally less violent than that of -burns; fluids not being capable of acquiring so high a temperature -as some solids, but flowing about with great facility, their effects -become most serious by extending to a large surface of the body. A burn -which instantly destroys the part which it touches may be free from -dangerous complications, if the injured part is confined within a small -compass; this is owing to the peculiar formation of the skin. - -The skin is made up of two layers; the outer one has neither blood -vessels nor nerves, and is called the scarf-skin or cuticle; the lower -layer is called the true skin, or cutis. The latter is richly supplied -with nerves and blood vessels, and is so highly sensitive we could not -endure life unless protected by the cuticle. The skin, while soft and -thin, is yet strong enough to enable us to come in contact with objects -without pain or inconvenience. - -The extent of the surface involved, the depth of the injury, the -vitality and sensibility of the parts affected must all be duly weighed -in estimating the severity and danger of an accident in any given case. - -In severe cases of burns or scalds the clothes should be removed _with -the greatest care_—they should be carefully cut, at the seams, and not -pulled off. - -In scalding by boiling water or steam, cold water should be plentifully -poured over the person and clothes, and the patient then be carried to -a warm room, laid on the floor or a table but not put to bed, as there -it becomes difficult to attend further to the injuries. - -The secret of the treatment is to avoid chafing, _and to keep out the -air_. Save the skin unbroken, if possible, taking care not to break -the blisters; after removal of the clothing an application, to the -injured surface, of a mixture of _soot and lard_, is, according to -practical experience, an excellent and efficient remedy. The two or -three following methods of treatment also are recommended according to -convenience in obtaining the remedies. - -Take ice well crushed or scraped, as dry as possible, then mix it with -fresh lard until a broken paste is formed; the mass should be put in a -thin cambric bag, laid upon the burn or scald and replaced as required. -So long as the ice and lard are melting there is no pain from the burn, -return of pain calls for a repetition of the remedy. - -The free use of soft soap upon a fresh burn will remove the fire from -the flesh in a very little time, in 1/4 to 1/2 an hour. If the burn be -severe, _after relief from the burn_, use linseed oil and then sift -upon it wheat flour. When this is dried repeat the oil and flour until -a complete covering is formed. Let this dry until it falls off, and a -new skin will be formed without a scar. - -In burns with lime, soap lye, or _any caustic alkali_, wash abundantly -with water (do not rub), and then with weak vinegar or water containing -a little sulphuric acid; finally apply oil, paste or mixture as in -ordinary burns. - -It would be well to always keep ready mixed an ointment for burns; -in fact a previous readiness for an accident robs it of half its ill -effects. - - -GLUE BURN MIXTURE. - -A method in use in the N. Y. City Hospital known as the “glue burn -mixture” is composed as follows: “7-1/2 Troy oz. white glue, 16 fluid -oz. water, 1 fluid oz. glycerine, 2 fluid drachms carbolic acid. Soak -the glue in the water until it is soft, then heat on a water bath until -melted; add the glycerine and carbolic acid and continue heating until, -in the intervals of stirring, a glossy strong skin begins to form over -the surface. Pour the mass into small jars, cover with parafine papers -and tin foil before the lid of the jar is put on and afterwards protect -by paper pasted round the edge of the lid. In this manner the mixture -may be preserved indefinitely. - -“When wanted for use, heat in a water bath and apply with a flat brush -over the burned part.” - - -=_Insensibility from Smoke._=—To recover a person from this dash cold -water in the face, or cold and hot water alternately. Should this fail -turn the patient on his face with the arms folded under his forehead; -apply pressure along the back and ribs and turn the body gradually on -the side; then again slowly on the face, repeating the pressure on the -back: continue the alternate rolling movements about sixteen times a -minute until breathing is restored. A warm bath will complete the cure. - - -=_Heat-stroke or Sun-stroke._=—The worst cases occur where the sun’s -rays never penetrate and are caused by the extreme heat of close and -confined rooms, overheated workshops, boiler-rooms, etc. The symptoms -are: 1, a sudden loss of consciousness; 2, heavy breathing; 3, great -heat of the skin; and 4, a marked absence of sweat. - -_Treatment._—The main thing is to lower the temperature. To do this, -strip off the clothing, apply chopped ice wrapped in flannel to the -head; rub ice over the chest, and place pieces under the armpits and -at the side. If no ice can be had use sheets or cloths wet with cold -water, or the body can be stripped and sprinkled with cold water from a -common watering pot. - - -=_Cuts and Wounds._=—In these the chief points to be attended to are: -1, arrest the bleeding; 2, remove from the wound all foreign bodies as -soon as possible; 3, bring the wounded parts opposite to each other and -keep them so; this is best done by means of strips of adhesive plaster, -first applied to one side of the wound and then secured to the other; -these strips should not be too broad, and space must be left between -the strips to allow any matter to escape. Wounds too extensive to be -held together by plaster must be stitched by a surgeon, who should -always be sent for in all severe cases. - -For washing a wound, to every pint of water add 2-1/2 teaspoonfuls -of carbolic acid and 2 tablespoonfuls of glycerine—if these are not -obtainable, add 4 tablespoonsful of borax to the pint of water—wash the -wound, close it, and apply a compress of a folded square of cotton or -linen; wet it in the solution used for washing the wound and bandage -down quickly and firmly. If the bleeding is profuse, a sponge dipped in -very hot water and wrung out in a cloth should be applied as quickly as -possible—if this is not to be had, use ice or cloth wrung out in ice -water. - -Wounds heal in two ways. 1, rapidly by primary union, without -suppuration, and leaving only a very fine scar. 2, slowly by -suppuration and the formation of granulations and leaving a large red -scar. - - -=_Bleeding._=—This is of three kinds: 1, from the arteries which lead -from the heart; 2, that which comes from the veins, which take the -blood back to the heart; 3, that from the small veins which carry the -blood to the surface of the body. In the first, the blood is bright -scarlet and escapes as though it was being pumped. In the second, the -blood is dark red and flows away in an uninterrupted stream. In the -third, the blood oozes out. In some wounds all three kinds of bleeding -occur at the same time. - -The simplest and best remedy to stop the bleeding is to apply direct -pressure on the external wound by the fingers. Should the wound be long -and gaping, a compress of some soft material large enough to fill the -cavity may be pressed into it; but this should always be avoided, if -possible, as it prevents the natural closing of the wound. - -Pressure with the hands will not suffice to restrain bleeding in -severe cases for a great length of time and recourse must be had to a -ligature; this can best be made with a pocket handkerchief or other -article of apparel, long enough and strong enough to bind the limb. -Fold the article neck-tie fashion, then place a smooth stone, or -anything serving for a firm pad, on the artery, tie the handkerchief -loosely, insert any available stick in the loop and proceed to twist -it, as if wringing a towel, until just tight enough to stop the flow. -Examine the wound from time to time, lessen the compression if it -becomes very cold or purple, or tighten up the handkerchief if it -commences bleeding. - -Some knowledge of anatomy is necessary to guide the operator where to -press. Bleeding from the head and upper neck requires pressure to be -placed on the large artery which passes up beside the windpipe and just -above the collar bone. The artery supplying the arm and hand runs down -the inside of the upper arm, almost in line with the coat seam, and -should be pressed as shown in Fig. 185. The artery feeding the leg and -foot can be felt in the crease of the groin, just where the flesh of -the thigh seems to meet the flesh of the abdomen and this is the best -place to apply the ligature. In arterial bleeding the pressure must be -put between the heart and the wound, while in _venous_ bleeding it must -be beyond the wound to stop the flow as it goes towards the heart. - -In any case of bleeding, the person may become weak and faint; unless -the blood is flowing actively this is not a serious sign, and the quiet -condition of the faint often assists nature in staying the bleeding, by -allowing the blood to clot and so block up any wound in a blood vessel. -Unless the faint is prolonged or the patient is losing much blood, it -is better not to hasten to relieve the faint condition; when in this -state anything like excitement should be avoided, external warmth -should be applied, the person covered with blankets, and bottles of hot -water or hot bricks applied to the feet and arm-pits. - - -=_Frost-bite._=—No warm air, warm water, or fire should be allowed near -the frozen parts until the natural temperature is nearly restored; rub -the affected parts gently with snow or snow water in a cold room; the -circulation should be restored very slowly; and great care must be -taken in the after treatment. - - -=_Broken Bones._=—The treatment consists of, 1, carefully removing -or cutting away, if more convenient, any of the clothes which are -compressing or hurting the injured parts; 2, very gently replacing the -bones in their natural position and shape, as nearly as possible, and -putting the part in a position which gives most ease to the patient; 3, -applying some temporary splint or appliance, which will keep the broken -bones from moving about and tearing the flesh; for this purpose, pieces -of wood, pasteboard, straw, or firmly folded cloth may be used, taking -care to pad the splints with some soft material and not to apply them -too tightly, while the splints may be tied by loops of rope, string, or -strips of cloth; 4, conveying the patient home or to a hospital. - -The bearer then places his arm behind the back of the patient and -grasps his opposite hip, at the same time catching firmly hold of the -hand of the patient resting on his shoulder, with his other hand; then -by putting his hip behind the near hip of the patient, much support is -given, and if necessary, the bearer can lift him off the ground and as -it were, carry him along. - - -=_Poultices._=—These outward applications are useful to relieve -sudden cramps and pains due to severe injuries, sprains and colds. -The secret of applying a mustard is to apply it hot and keep it so by -frequent changes—if it gets cold and clammy it will do more harm than -good. Poultices to be of any service and hold its heat should be from -one-half to one inch thick. To make it, take flaxseed, oatmeal, rye -meal, bread, or ground slippery elm; stir the meal slowly into a bowl -of boiling water, until a thin and smooth dough is formed. To apply it, -take a piece of old linen of the right size, fold it in the middle; -spread the dough evenly on one half of the cloth and cover it with the -other. - -To make a “mustard paste” as it is called, mix one or two -tablespoonfuls of mustard and the same of fine flour, with enough water -to make the mixture an even paste; spread it neatly with a table knife -on a piece of old linen, or even cotton cloth. Cover the face of the -paste with a piece of thin muslin. - - -=_How to Carry an Injured Person._=—In case of an injury where walking -is impossible, and lying down is not absolutely necessary, the injured -person may be seated in a chair, and carried; or he may sit upon a -board, the ends of which are carried by two men, around whose necks he -should place his arms so as to steady himself. - -Where an injured person can walk he will get much help by putting his -arms over the shoulders and round the necks of two others. - -A seat may be made with four hands and the person may be thus carried -and steadied by clasping his arms around the necks of his bearers. - -If only one person is available and the patient can stand up, let him -place one arm round the neck of the bearer, bringing his hand on and in -front of the opposite shoulder of the bearer. - -To get at a broken limb, or rib, the clothing must be removed, and -it is essential that this be done without injury to the patient; the -simplest plan is to rip up the seams of such garments as are in the -way. Boots must be cut off. It is not imperatively necessary to do -anything to a broken limb before the arrival of a doctor except to keep -it perfectly at rest. - -To carry an injured person by a stretcher (which can be made of a -door, shutter, or settee—with blankets or shawls or coats for pillows) -three persons are necessary. In lifting the patient on the stretcher -_it should be laid with its foot to his head_, so that both are in the -same straight line; then one or two persons should stand on each side -of him, and raise him from the ground, slip him on the stretcher; this -to avoid the necessity of any one stepping over the stretcher, and the -liability of stumbling. If a limb is crushed or broken, it may be laid -upon a pillow with bandages tied around the whole (_i.e._, pillow and -limb) to keep it from slipping about. In carrying the stretcher the -bearers should “break step” with short paces; hurrying and jolting -should be avoided and the stretcher should be carried so that the -patient may be in plain sight of the bearers. - - - - -PERSONAL. - - -_The fireman, so called, in steam service of any description, should -and does on the average receive double the compensation of a man who -has only his labor to bargain for._ - -_In addition, he exercises his skillful vocation in sheltered places -and is almost the last of the employees of a plant to be “laid off” and -is certainly the first to be called on again after stoppage._ - -_Still further, the fireman has an almost equal opportunity, with -the best shop trained machinist, for advancement to the position of -engineer in charge of the most extensive steam plants._ - -_Now! this increased pay over ordinary labor and other numerous -advantages accruing from the position, demand a generous return, and -in ending this work, the author suggests these “points” for observance -to the aspiring student, whether engineer, fireman, or machinist, -namely—that sobriety should be held one of the first elements of strict -observance; an unresting tidiness of person and premises; dignity of -conduct, as being owed to the rising profession of steam engineering; -and lastly, an unswerving fidelity of trust, which may include honesty, -truthfulness and courage._ - - - - -INDEX - -FOR - -MAXIMS AND INSTRUCTIONS. - - - =Accidents and Emergencies=, 313. - Factory rules to prevent, 293. - Government rules to prevent, 290. - - =Acid=, definition, 137. - - =Advantages= of triple draught tubular boiler, 84. - - =Air= used in burning 1 lb. of coal, 14. - ditto, how supplied to the coal, 14. - Description, 16. - As a material substance, 16. - Density at different depths, 16. - Weight of a column of air, 17. - As a fluid, 17. - As an impenetrable body, 17. - Five “points” for the engineer, 17. - Composition of, 17. - Specific heat of, 215. - - =Air valve=, use of, 255. - - =Alcohol=, specific heat of, 214. - - =Alkalies=, definition, 137. - - =Alum=, boiling point of, 37. - - =Ammoniac (Sal)=, boiling point of, 37. - - =Analysis= of anthracite coal, 13. - Of bituminous coal, 13. - Of wood, 13. - Of heat, 13. - Of scale deposited in marine boilers, 146. - Of feed waters, 139-140. - - =Angle= and T iron, dimensions and shape, 104. - - =Angle brick=, 237. - - =Angle-valve=, description, 273. - - =Anthracite coal=, analysis of, 13. - Ignited with difficulty, 16. - - =Antimony=, melting point, 42. - - =Answers= of applicants for a marine license, 127. - - =Arch-brick=, 237. - - =Area of safety valve=, rule for finding, 192. - - =Ash pit=, the, 238. - How kept during firing, 27. - - =Assistant engineers=, classification of, 310. - - - =Back pressure valves=, description, 273. - - =Baffle plate=, description, 169, 180. - - =Ball valve=, description, 273. - - =Bark=, effect on steam boilers, 151. - - =Barrel=, rule for finding contents of, 203. - - =Bars=, grate, description, 173. - - =Before lighting the fire=, directions, 25. - - =Belts=, how to safely run on pullies, 291. - - =Bending= lead pipe, 304. - - =Bib cock=, description, 273. - - =Bituminous coal=, analysis of, 13. - How burned, 16. - - =Blast pipe= for marine boiler, 63. - - =Bleeding=, treatment of, 317. - - =Blowers= for shavings, 20. - - =Blow off=, description, 81. - Surface, description, 161. - - =Boilers=, description, 48. - Upright steam, 50. - Crude form, 52. - Plain cylinder, description, 52. - Cornish, description, 54. - Lancashire, description, 55. - Galloway, description of, 58. - Marine, description of, 60. - Marine, table of dimensions, 62. - Locomotive portable, 80. - Construction of, 89. - Caulking, 94. - Dangers from syphoning, 288. - Dangers from gas, 288. - Foaming in, 42. - Fulcring, 94. - Horse power of, 234. - Proper steam connection for, 276. - - =Boiler braces=, “points” relating to, 104. - - =Boiler coverings=, 273. - - =Boiler=, Compound, composition of, 151-152. - Compound, for locomotives, 149. - - =Boiler castings=, specification of, 86. - - =Boiler cleaners=, mechanical description, 159, 160. - - =Boiler explosions=, causes of, 286. - - =Boiler fittings= and mountings, 87. - Fixtures, description, 164. - - =Boiler flue brushes=, use of, 21. - - =Boiler fronts=, description, 165. - - =Boiler injector=, description, 206. - - =Boiling=, process of, 37. - - =Boiling points= of various substances, 37. - - =Boiler maker’s= tools and machinery, 281. - - =Boilers newly set=, how fired, 28. - No two alike, 25. - - =Boiler and pipe covering=, mixtures for, 275-276. - - =Boiler plates=, example of riveting, 114. - Marks on, 88. - - =Boiler repairs=, 123. - Note, 125. - - =Boiler scale=, analysis of, 148. - - =Boiler scum=, how formed, 150. - - =Boiler setting=, 236. - - =Boiler steel=, description of quality, 90. - - =Boiler tubes=, dimensions of lap welded tubes, 110. - Table of holding power, 111. - Experiments in strength of, 111. - Notes, 110, 112. - Illustration of size, 245. - - =Boiler testing=, specification, 87. - - =Bolts=, strain on, rule, 99. - Socket, description, 103. - - =Bolt=, plumber’s copper pointed, 308. - - =Bones=, broken, treatment of, 318. - - =Borer=, tap, plumber’s, 306. - - =Box coil=, description, 257. - - =Brace=, difference between, and stay, 103. - Head to head, description, 103. - Crow foot, 103. - - =Braces=, shop names for, 103. - Table for calculations, 107-109. - Table of diameters, 103. - Inspector’s rules, 102. - Specification for, 86. - “Points” relating to, 104. - - =Bracing= of steam boilers, 96. - - =Bracket=, valve, description, 272. - - =Brass=, conducting power of, 213. - - =Brick=, furnace, 237. - - =Brine valve=, description, 277. - - =Broken bones=, treatment of, 318. - - =Burns and scalds=, treatment of, 313. - - =Burn mixture=, 315. - - =Bushing=, description, 274. - - =Butt joint=, illustration, 115. - - - =Calculations= relating to steam heating, 262. - Relating to pumps, 22. - Relating to safety valves, 191. - - =Calipers=, use of, 22. - - =Cape chisel=, 307, 281. - - =Carbon=, description of, 229. - - =Carbonate=, definition, 136. - Of magnesia, definition, 138. - Of lime, at what temperature deposited, 148. - - =Carbonic acid=, in water how detected, 153-154. - Specific heat of, 215. - - =Carbonic acid gas=, description of, 230. - - =Carbonic oxide=, description of, 231. - Specific heat of, 215. - - =Carbonization=, method of, 15. - - =Care and management= of the steam boiler, 24. - - =Care of steam fittings=, 268. - - =Care of water tube boilers=, 70. - - =Castings=, for boiler, specification, 86. - - =Caulking=, description, 94. - - =Caulking tools=, plumber’s, 308. - - =Certificates of Inspection=, issuing of, 131. - - =Chain riveting=, example, 93. - - =Chapter of “Don’ts,”= 44-47. - - =Charcoal=, description, 15. - Specific heat of, 214. - - =Charcoal Iron=, description, 88. - - =Check valve=, description, 273. - - =Chemical terms= relating to feed water, 136. - - =Chemistry=, definition, 136. - - =Chemistry of the furnace=, 226. - - =Chief engineers=, classification of, 310. - - =Chimney= draught, 296. - - =Chisel=, cold, 307. - Cape, 307. - Round nose, 307. - Half round nose, 307. - Wood, 307. - Diamond nose, 307. - Gasket, 308. - - =Chloride=, definition, 137. - - =Chlorides=, how indicated in water, 157. - - =C. H. No. 1 F=, 88. - - =C. H. No. 1 FB=, 88. - - =Circle brick=, 237. - - =Circulation=, water, 294. - - =Cisterns=, capacity of, 202. - - =Clamp=, boiler, description and cut, 123. - - =Classification of marine engineers=, 310. - - =Cleaners=, mechanical boiler, description, 159-180. - - =Cleaning out boilers= under firing, 20. - - =Coal tar=, how best fired, 30. - - =Coal=, 13. - What it consists of, 13. - Common proportions, 13. - Introduction of air in burning, 13. - Bituminous, how it burns, 16. - Anthracite, how it burns, 16. - Comparative evaporation, 18. - Specific heat of, 214. - Storing and handling of, 225. - - =Cocks,= description, 270. - Valve, description, 272. - Gauge, description, 170. - Bib, description, 273. - Three way, description, 273. - Four way, description, 273. - - =Coil=, box, description, 257. - Pipe, description, 257. - - =Coke=, description, 15. - Comparative evaporation, 18. - Ratio between heating and grate surface, 28. - How best fired, 28. - Specific heat of, 214. - - =Cold chisel=, 307. - - =Cold short=, definition, 121. - - =Columns=, glass water gauge, 177. - - =Combustible= parts of coal, 16. - - =Combustion=, operation on materials, 16. - Chamber, 238. - Chambers of marine boilers, 62. - - =Compasses=, use of, 22. - - =Compass saw=, 308. - - =Compound=, boiler, composition, 151-2. - For locomotive boilers, 149. - - =C No. 1=, iron, 88. - - =Condenser=, surface description, 65. - Operation of, 66. - - =Conducting power= of various substances, 213. - - =Conical head= of rivets, description, 113. - - =Construction= of boilers, description, 89. - And drawing rivet heads, 113. - - =Contraction of area=, definition, 121. - - =Conveyors=, screw, 20. - - =Copper=, conducting power of, 213. - Radiating power of, 213. - Specific heat of, 214. - - =Cornish boiler=, description of, 54. - Defects of, 54. - - =Corrosion= of steam boilers, 126, 142, 144. - - =Coverings= for pipes and boilers, 275. - - =Coupling=, description, 274. - For pipe, 250. - - =Cracks= in boilers, how to repair, 123. - - =Cross T=, description, 274. - - =Crowfoot brace=, 103. - - =Cup head= of rivets, description, 118. - - =Cutaway front=, description, 165-167. - - =Cuts and wounds=, treatment of, 316. - - =Cylinder boiler=, description, 52. - Defects of, 53. - - - =Dampers= and doors to the furnace, 39. - - =Damper regulators=, description, 185. - - =Danger=, points, in steam boiler, 125. - - =Dart=, description and cut, 19. - - =Dead end= of pipe, 284. - - =Dead plate=, description, 180, 237. - - =Dead steam=, description, 282. - - =Dedication=, 5. - - =Defects=, table of, 125. - - =Defects= and necessary repairs to boilers, 123. - - =Definition of Terms=, 121. - - =Designing boilers=, relating to stayed surfaces, 99. - - =Device= for using kerosene oil, 158. - - =Diamond nose chisel=, 307. - - =Directions= before lighting the fire, 25. - For firing with various fuels, 27. - - =Disc= for boiler makers, 281. - - “=Don’ts=,” a chapter of, 44-47. - - =Doors=, furnace, description, 168-170. - - =Double seat valve=, description, 273. - Also see Fig. 158. - - =Drain=, the steam, description, 81. - - =Drainage and piping=, description and illustration, 299. - - =Drain cock=, description, 181. - - =Draughts=, at time of lighting the fire, 26. - Of chimney, 296. - Regulating the draught, 41. - - =Drawings= of rivet heads, 118. - - =Drum=, mud, description, 179. - - =Dry steam=, description, 282. - - =Ductile=, definition, 121. - - =Dudgeon expanders=, description, 281. - - =Duties of the fireman=, 27. - - =Duty of boiler=, specification, 87. - - =Dust= (coal), firing of, 40. - - - =Economizer=, fuel, description, 185. - - =Elasticity=, definition, 121. - - =Elastic limit=, definition, 121. - - =Elbow=, description, 274. - - =Element=, definition, 136. - - =Ell=, description, 274. - - =Elongation= of steel plate, 90. - Definition, 121. - - =Ether=, specific heat of, 214. - - =Engineer’s questions=, 133. - Examinations, “points,” 133. - Tests for impurities in water, 153. - - =Evans, Oliver.=, viii. - - =Examination= of engineers, 133. - - =Exhaust steam= heating, 267. - - =Expanders= (dudgeon), 281. - - =Expansion= (linear), of steam pipe, 270. - - =Explosions=, boiler, 286. - Of steam pipe, 287. - - - =Factory rules= to prevent accident, 293. - - =Fatigued=, definition, 121. - - =Feed water=, analysis of, 139-140. - Engineer’s tests, 153. - A precipitator for sea water, 146. - Examples of analysis, 140-141. - Preliminary precipitation, 144. - Description, 196. - Heaters, “points” relating to, 201. - Heaters, table of savings, 200. - Purifier, description, 185. - - =Fire=, thickness of, 40. - What to do in case of, 40. - - =Fire box iron=, description, 88. - - =Fire brick arch= in locomotive, 35. - - =Fire clay=, conducting power of, 213. - - =Fire door=, 237. - - =Fire irons=, 21. - - =Firemen=, advantages of trained, 24. - - =Fire pails=, use of, 21. - - =Firing=, trick of, 24. - Boilers newly set, 28. - With straw, description, 31. - Duties of the fireman, 27. - Ocean steamer, description, 32. - Improper method, 27. - Proper method, 26. - With oil, description, 32. - With coal tar, description, 30. - Of twenty horse power, description, 30. - Sixteen steam boilers, description, 29. - With shavings, 33. - With coke, directions, 28. - Of steam boilers, 24. - Under a boiler, gases and solids produced, 16. - With saw dust, 33. - A new plant, 37. - With coal dust and screenings, 40. - - =Firing= with tan bark, 36. - Boilers, experiments in England, 40, - A locomotive, 35. - - =Files=, use of, 21. - - =Fish trap=, 205. - - =Fittings= of marine boilers, 63. - For boiler, specification, 87. - - =Fixtures=, boiler, description, 164. - - =Flame=, luminous, 41. - Of anthracite coal, 16. - - =Flange iron=, description, 88. - - =Flange of boiler head=, proper radius, 103. - - =Flanges= for pipe, 248. - - =Flanges=, how to be turned, etc., 85. - - =Flat surfaces= in boilers, how to stay, 98. - - =Flues and tubes=, sweeping, 39. - - =Flush front=, description, 165-166. - - =Foaming in boilers=, 42. - - =Four way cock=, description, 273. - - =Fronts=, boiler, description, 165. - - =Frost-bite=, treatment of, 317. - - =Fuel=, loss of, by incrustation, 143. - - =Fuel economizer=, description, 185. - - =Fuel-oil=, 289. - Rules relating to, 290. - - =Fuels=, liquid and gas, 15. - Table of comparative evaporative value, 18. - - =Fullering=, description, 94. - - =Fulton, Robert=, viii. - - =Furnace=, temperature of, 42. - Fire, kindling of, 241. - Chemistry of, 229. - Dampers and doors, 39. - Doors, description, 168-170. - The, 237. - - =Fusible plugs=, description, 171, 172. - - - =Galloway boiler=, description of, 58. - Table of dimensions, 60. - - =Gas=, difference between it and a liquid, 216. - As a fuel, 15. - From coal, comparative evaporation, 18. - Dangers from, in idle boilers, 288. - Amount burned in ventilating pipes, 265. - - =Gasket= chisel, 308. - - =Gas pipe=, illustrations of size, 243. - - =Gas pliers=, description, 269. - - =Gate valve=, description, 273. - - =Generators=, steam, description, 48. - - =Glass=, specific heat of, 214. - Radiating power of, 213. - - =Glass gauges=, description, 177. - - =Glass water gauge columns=, 177. - - =Globe valve=, description, 272. - - =Gold=, radiating power of, 213. - Conducting power of, 213. - - =Grate=, the, 237. - - =Grate bars=, description, 173. - How to preserve from excessive heat, 38. - Shaking grates, 174. - How kept during firing, 27. - - =Grooving= of steam boilers, 126. - List of cases, 125. - - =Growth= of the steam boiler, 52. - - =Gauge=, steam, description, 181. - - =Gauge cocks=, description, 176. - - =Gauges=, glass, description, 177. - - =Gauges=, pressure recording, description, 233. - - =Gusset stays=, description, 100, 103. - - - =Hammer=, water, description, 283. - Pein, 306. - - =Hammer test= of rivets, 95. - - =Hand-hole plates=, description, 81. - - =Hanger= for pipes, 308. - - =Hazards= of fuel-oil, 289. - Of the boiler room, 285. - - =Heads of rivets=, cup, conical, pan heads, 113. - - =Head to head= brace, description, 103. - - =Heat=, laws of, 212. - Unit of, 214. - Specific, 214. - How it becomes effective, 13. - - =Heaters=, feed water, description, 196. - - =Heating=, steam and hot water, 251. - By exhaust steam, 267. - - =Heat proof paints=, 232. - - =Heat stroke=, treatment of, 315. - - =High pressure steam=, 283. - - =Hinged valves=, description, 272. - - =Hoes=, use of, 21. - - =Homogeneous=, definition, 121. - - =Horizontal tubular boiler=, description, 79. - Parts of, 81. - Table of sizes, 77. - - =Horse power=, rule for estimating, 235. - As applied to boilers, 234. - - =Hose=, rubber, use of, 21. - - =Hot short=, definition, 122. - - =How to carry= injured persons, 319. - - =How to prepare= for inspection of steam boilers, 130. - - =Hydrogen=, specific heat of, 215. - Description of, 230. - - =Hydraulic test=, 131. - - - =Ice=, radiating power of, 213. - Specific heat of, 214. - - =Improper method of firing=, cuts and description, 27. - - =Incrustation= of steam boilers, 142-144. - Example of, 142. - And scale, list of cases, 125. - Table showing quantity collecting, 103. - Of boilers, “points” relation to, 149-152. - - =Individuality= of each steam boiler, 25. - - =Injector=, description, 206. - - =Injured persons=, how to carry, 319, 320. - - =Inspection= of steam boilers, 129. - How to make ready for, 129-130. - - =Inspector’s questions= to applicant, 128. - - =Inspector’s rules= relating to braces, 102. - - =Interceptor=, steam, description, 183. - - =Introduction=, 10. - - =Iron=, T, description of, 103. - (Hammered), melting point, 42. - (Wrought), melting point, 42. - Fire box, description, 88. - Charcoal iron, description, 88. - (Wrought), conducting power of, 213. - Polished, radiating power of, 213. - Specific heat of, 214. - Melting point, 42. - Flange, description, 88. - Cast, conducting power of, 213. - - =Irons=, fire, 21. - - =Issuing certificates= of inspection, 131. - - - =Jackscrews=, description, 281. - - =Jam brick=, 237. - - =Joints=, putty, how to make, 303. - - =Joints of lead pipe=, 300. - - =Joints of pipes=, 248. - - - =Kerosene oil= in boilers, “points” of, 156-7. - - =Kindling a furnace fire=, 241. - - - =L=, description, 274. - - =Lace cutters=, use of, 21. - - =Ladders=, use of, 21. - - =Ladle=, 306. - - =Lamp black=, radiating power of, 213. - - =Lancashire boiler=, description, 55. - Defects of, 55. - - =Language= of steam boilers, 39. - - =Lanterns=, use of, 21. - - =Lap joint=, illustration, 115. - - =Laws= of heat, 212. - - =Lazy bar=, description, 20. - - =Lead=, 299. - Advantages in use of, 299. - Melting point, 42. - Conducting power of, 213. - Wrought, radiating power of, 213. - Specific heat of, 214. - Polished, radiating power of, 213. - - =Lead pipe=, how to make putty joints, 304. - Table of sizes and weights, 305. - How to bend, 304. - - =Lead pipe joints=, 300. - - =Lever=, length, rule, 193. - - =Lifting valves=, description, 273. - - =Lime=, definition, 138. - - =Liquid=, difference between it and a gas, 216. - - =Litmus paper=, definition, 153. - - =Live steam=, description, 282. - - =Locknut=, description, 274. - - =Locomotive=, firing of, 35. - Boiler Compound, 149. - Or charging shovel, description, 19. - - =Locomotive boilers=, description, 72. - How to rivet, 115. - - =Locomotive= portable boiler, description, 80. - - =Looking glass=, 307. - - =Loop=, (steam), description of, 278-280. - - =Low pressure steam=, 283. - - =Lugs=, specification of, 86. - - =Luminous flame=, 41. - - - =Magnesia=, definition, 138. - At what temperature deposited, 148. - Carbonate of, definition, 138. - - =Malleable=, definition, 121. - - =Manhole cover=, description, 81. - - =Manhole plates=, specification, 86. - - =Marine boilers=, description of, 60. - How to rivet, 115. - Fittings for, 63. - Table of dimensions, 62. - Super heaters, 64. - Use of zinc in, 162. - Blast pipe for, 63. - Uptakes, 64. - Parts which first give way, 112. - Incrustation and scaling of, 146-147. - - =Marine engineers= classification of, 310. - Rules relating to, 309. - - =Marks= on boiler plates, 88. - - =Marble=, conducting power of, 213. - - =Materials=, 12, 13. - - =Mechanical scrapers=, 187. - - =Mechanical stokers=, 134-135. - - =Mercury=, specific heat of, 214. - Radiating power of, 213. - - =Meters=, water, description, 203. - - =Moisture=, in wood, 14. - - =Mouth piece=, furnace, 236. - - =Mud drum=, description, 179. - - - =Newly set boilers=, how fired, 28. - - =Nickel steel= boiler plates, description, 91. - - =Nipple=, description, 274. - - =Nitric acid=, boiling point of, 37. - - =Nitrogen=, specific heat of, 215. - Description of, 230. - - =Non-conductors=, 276. - - =Noiseless water-heater=, 312. - - - =Ocean steamer=, how to fire, 32. - - =Oil=, fuel, 289. - Kerosene, in boilers, “points” of, 156-157. - Specific heat of, 214. - Firing with, 32. - - =Ore barrow=, use of, 20. - - =Organic matter= in water, how indicated, 154. - - =Ornamental paints=, 232. - - =Overhanging front=, description, 165-167. - - =Overhead system= of heating, 256. - - =Oxide=, definition, 136. - Of iron how best treated, 148. - - =Oxygen=, description of, 229. - Specific heat of, 215. - United with coal, 17. - - - =Paints=, heat proof, 232. - - =Palm stays=, description, 100. - - =Pan head= of rivets, description, 113. - - =Patch-screw=, description and cut, 123. - - =Peat=, description, 14. - Analysis of, 13. - Charcoal, description, 15. - Comparative evaporation, 18. - - =Pein hammer=, 306. - - =Petroleum=, as a fuel, 15. - Oil, comparative evaporation, 18. - In boilers, use of, 155. - - =Philadelphia Water Works= example of gain in good firemen, 25. - - =Pipes=, table of surfaces and capacities, 246. - Joints of, 248. - How to weld, 264. - Used for ice machinery, 263. - Table of “data” relative to, 247. - - =Pipes and piping=, description, 244. - - =Pipe coil=, description, 257. - - =Pipe couplings=, 250. - - =Pipe cutter=, description and cut, 269. - - =Pipe hanger=, 308. - - =Pipe=, gas, illustration of size, 243. - - =Pipe tongs=, description, 269. - - =Pipe union=, description, 274. - - =Piping=, dead end, 284. - - =Piping and drainage=, description and illustration, 209. - - =Pitting=, of steam boilers, 126. - - =Planer=, (power), for boiler makers, 281. - - =Plate=, dead, description, 180. - Quality of steel, 90. - - =Plates=, baffle, description, 180. - Burned and blistered, list, 125. - For boilers, table of thicknesses, 113. - - =Pliers=, gas, description, 269. - - =Plug=, description, 274. - - =Plugs=, fusible, description, 171-172. - - =Plumb-bob=, description, 306. - - =Plumber’s solder=, how to make, 305. - - =Plumber’s tools=, description, 306-309. - Solder, rule for making, 305. - - =Plumber’s wipe joint=, 298. - - =Plumbing=, description and cuts, 298. - What engineers should know, 298. - - “=Points=” relating to firing, 37. - Relating to boiler braces, 104. - Of danger in steam boiler, 125. - Relating to grate bars, 175. - Relating to water gauge cocks, 176. - Relating to glass gauges, 177. - Relating to the steam gauge, 182. - Relating to safety valves, 194. - Relating to feed water heaters, 201. - Relating to water meters, 204. - Relating to injectors, 209. - Relating to pumps, 218-221. - Relating to boiler setting, 239-241. - Relating to steam heating, 254. - Relating to chimneys and draught, 297. - - =Poker=, description and cuts, 19. - - =Portable= boiler, locomotive, description, 80. - Car track, use of, 20. - - =Potter, Humphry=, inventor of valve motion, 270. - - =Poultices=, how to make, 319. - - =Power planer= for boiler makers, 281. - - =Power punch= for boiler makers, 281. - - =Precipitation= of impurities in feed water, 144. - - =Preface=, 7. - - =Preparation= for firing steam boilers, 24. - - =Pressure gauges=, list of defective cases, 123. - Regulator valve, 274. - - =Pressure of safety valve=, rule, 192. - - =Principles= relating to water, 223. - - =Proper method of firing=, cut and description, 21. - - =Punch= for boiler makers, 281. - - =Pump=, description, 215. - Classification, 217. - Parts of, Illustration, 218. - Double acting, 218. - Direct pressure, 216. - Calculations relating to, 222. - Strainer, for, description, 223. - Points relating to, 218-221. - - =Putty joints=, how to make, 303. - - - =Questions= of applicant for marine license, 127. - Asked by examining engineers, 309. - Of proprietor, relating to steam boiler, 127. - - - =Radiant rays= of heat, “point,” 38. - - =Radiating power= of various substances, 213. - - =Radiation of heat=, law relating to, 39. - - =Railroad barrow=, use of, 20. - - =Ram=, water, 284. - - =Ratio= of grate to heating surface, 175. - - =Re-agent=, definition, 136. - - =Reamer=, plumber’s, 306. - - =Recording pressure gauges=, description, 233. - - =Reducing= coupling, description, 274. - - =Regulating= the draught, 41. - - =Regulations= relating to marine engineers, 309. - - =Regulators=, damper, description, 185. - - =Relief valve=, description, 272. - - =Repairing= leaky tubes, 126. - - =Repairs= to boilers, “points” on, 124-6. - - =Riveting=, modes of, 93. - Specification for, 86. - Description, 91. - Double description, 91. - Chain, example, 93. - Zig-Zag, example, 93. - Treble, example, 93. - Unequal pitches, example, 93. - Example of riveting boiler plates, 114-116. - Hammers for boiler makers, 281. - List of defective cases, 125. - - =Rivet heads= of cup, conical, pan heads, 113. - - =Rivet heating machines=, 261. - - =Rivets=, description, 93. - Steel, description, 95. - Table of diameters, 113. - - =Rivet set=, 307. - Tests, 95. - - =Riveted stays=, description, 106. - - =Rolls= for boiler makers, 281. - - =Rotary valves=, description, 273. - - =Round nose chisel=, 307. - - =Rubber hose=, use of, 21. - - =Rule= for estimating horse power of boilers, 235. - For finding area of valve opening, 195. - To find pressure in lbs. of column of water, 222. - To find area of steam piston of pump, 222. - To find quantity of water elevated, 222. - For finding contents of a barrel, 203. - For reading water meters, 204. - For making boiler and pipe covering, 275-276. - For making solder, 305. - For finding strain on bolts, 99. - For safe internal pressure, 117. - For determining areas of steam boilers, 105. - For calculating contents of steam and water in - the steam boiler, 105. - - =Rules=, U. S., regarding safety valves, 189. - For safety valves, 193. - Inspectors, relating to bracing, 102. - Relating to fuel oil, 290. - Factory, to prevent accident, 293. - Government, to prevent accident, 290. - Before lighting the furnace fire, 25. - - =Running= of steam boilers under fire, 24. - - - =Safe internal pressure=, rule and example, 117. - Tables, 118-120. - - =Safety factor= of steam boilers, 96. - - =Safety valves=, description, 187. - Rules, 191, 193. - Rule to find area of opening, 195. - Table showing rise of valve, 195. - List of defects, 125. - Points relating to, 194. - - =Salt=, definition, 138. - - =Sand-bending= of lead pipe, 304. - - =Saturated steam=, 283. - - =Saw=, compass. 308. - Plumber’s, 307. - - =Saw dust=, firing with, 33 , 242. - As a fuel, 16. - - =Sea water= precipitator, 145. - - =Sectional steam boilers=, description, 71. - - =Sentinel valve=, description, 184. - - =Separator=, steam, description, 183. - - =Set screws=, dangers arising from, 292. - - =Setting= of steam boilers, 236. - Of water tube boilers, 239. - - =Scalds=, treatment of, 313. - - =Scale= deposited in marine boilers, analysis, 146-147. - Boiler, analysis of, 148. - - =Scaling= of steam boilers, “points,” 149-152. - - =Scope of the work=, 12. - - =Scoop shovel=, cut and description, 19. - - =Scrapers=, mechanical, 187. - - =Screenings=, firing of coal dust and, 40. - - =Screw conveyors=, use of, 20. - - =Screw-jacks=, use of, 21. - - =Screw stays=, description, 101. - - =Scum= of boilers, how formed. 150. - - =Scumming apparatus=, description, 161. - - =Shaking grates=, description, 174. - - =Shavings=, firing with, 33. - Blowers, use of, 20. - - =Shearing strength=, definition, 121. - - =Shears= for boiler makers, 281. - - =Shell= of boiler, description, 81. - - =Shovels=, cut and description of, 19. - - =Side brackets= for boilers, 240. - - =Silica=, definition, 137. - - =Silver=, radiating power of, 213. - Conducting power of, 213. - Melting point, 42. - - =Six inch flue=, boiler, 78. - - =Slice bar=, description and cuts, 19. - “Point” relating to its use, 30. - - =Smoke=, insensibility from, treatment, 315. - - =Snips=, plumber’s, 306. - - =Socket bolts=, description, 103. - - =Soda=, definition, 138. - Proportion of, in water, 154. - Acetate of, boiling point of, 37. - - =Sodium=, definition, 138. - - =Solder=, rule for making plumber’s, 305. - - =Sounds=, or language of steam boilers, 39. - - =Source of power= in the steam engine, 13. - - =Specifications= for 125 H. P. steam boiler, 85. - - =Specific heat=, description, 214. - Table, 214. - - =Spectacle piece=, 124. - - =Spirit level=, 307. - - =Stay bolts=, hollow, description, 103. - - =Staying= of flat surfaces, 98. - - =Stays and braces=, list of defective cases, 125. - - =Stays=, gusset, description, 100. - Of marine boilers, 75. - Of locomotive boilers, 75. - “Points” relating to boiler stays, 104. - Palm, description, 100. - Screwed, description, 101. - And brace, difference, 103. - Table for calculations, 107-109. - - =Steam=, description, 282. - Specific heat of, 215. - Dry, 282. - Dead, 282. - Live, 282. - Saturated, 283. - Wet, 283. - High pressure, 283. - Low pressure, 283. - Superheated, 283. - Specific gravity of, 283. - Total heat of, 283. - - =Steam and hot water heating=, 251. - - =Steam boiler=, growth of the, 52. - Water tube, 67. - Sectional, description of, 71. - Triple draught, 81-82. - Six-inch flue, 78. - Two-flue, 78. - - =Steam boilers=, locomotive, 72. - Idle, dangers of, 288. - Inspector’s rules relating to bracing of, 102. - Use of petroleum in, 155. - Effect of sugar on, 150. - Corrosion and incrustation, 142. - Scaling of, “points,” 149-152. - Effect of bark on, 151. - Bracing, 96. - Specification for 125 H. P., 85. - - =Steam drum= or dome, description, 81. - - =Steam fitter’s vise=, 269. - - =Steam fittings=, care, 268. - Description, 274. - - =Steam gauge=, description, 181. - - =Steam generators=, 48. - - =Steam heating= by exhaust, 267. - How much space 1 H. P. will heat, 262. - - =Steam loop=, note relating to, 295. - Description, 278-280. - - =Steam pipe=, linear expansion of, 276. - - =Steam pipe explosions=, 287. - - =Steam pump=, 215. - - =Steam separator=, description, 183. - - =Steam space of boilers=, rule and example, 105. - - =Steam whistle=, description, 180. - - =Steel rivets=, description, 95. - - =Steel=, boiler, description, 90. - Melting point, 42. - Specific heat of, 214. - - =Steel plates=, nickel steel, description, 91. - Quality and thickness in, 85. - Quality of, 90. - - =Stephenson, George=, viii. - - =Stock and dies=, use of, 21. - - =Stoker=, mechanical, 134. - - =Storing coal=, 225. - - =Straightway valve=, description, 273. - - =Strainer=, for pump, description, 223. - - =Strain on bolts=, rule and example, 99. - - =Straw=, how best fired, 31. - Composition of, as fuel, 15. - - =Sugar=, effect of, on steam boilers, 150. - - =Sulphates=, how indicated, 154. - Definition, 137. - - =Sulphate of lime=, at what temperature deposited, 148. - - =Sulphur=, description of, 230. - - =Sulphuric acid=, boiling point of, 37. - - =Sunstroke=, treatment of, 315. - - =Superheated steam=, 283. - - =Superheater= of marine boiler, 64. - - =Surface blow off=, description, 161. - - =Surface condenser=, description, 65. - - =Swing valve=, description, 273. - - =Syphon=, dangers from, in boilers, 288. - - - =T=, description, 274. - - =T irons=, description and use, 103. - Dimensions and shape, 104. - - =Table= of evaporation, 18. - Melting points of metals, 42. - Temperature, judged by color, 42. - Of dimensions, Galloway boiler, 60. - Of marine boilers, 62. - Diameter of braces, 103. - For calculating the number of stays, 107-109. - Of dimensions of boiler tubes, 110. - Holding power of boiler tubes, 111. - Of diameter of rivets and thickness of plate, 113. - Of safe internal pressure, 118-120. - Of defects found in steam boilers, 125. - Showing loss at different thicknesses by corrosion, 143. - Showing sediment collecting in boilers, 163. - Showing rise of safety valve, 195. - Of savings from use of feed water, 200. - Capacity of cisterns, 202, - Of specific heat, 214. - Of conducting power of various substances, 213. - Of radiating power of various substances, 213. - Weight of cubic foot of water, 224. - Weight and capacity of gallons of water, 225. - Comparative quantity of water which can be evaporated, 231. - Surfaces and capacities of pipes, 246. - Of data relating to pipes, 247. - Bursting pressure of tubes, 264. - Of weights of round and plate iron, 309, 311. - Conducting power of various substances, 275. - Relative value of non-conductors, 276. - Weights of lead pipe, 305. - - =Tan=, description, 15. - - =Tan bark=, comparative evaporation, 18. - Firing with, 36. - - =Tanks=, for fuel oil, how to construct, 290. - - =Tan-liquor=, unsafe use of, in boilers, 185. - - =Tap-borer=, plumber’s, 306. - - =Taps and dies=, description, 269. - - =Tee=, description, 274. - - =Temperature= of a furnace, 42. - - =Tensile strength= of steel plate, 90. - Of boilers, 121. - - =Test=, the hydraulic, 131. - - =Testing-boiler=, specification, 87. - - =Testing boilers= under steam pressure, 287. - - =Test pieces=, description and illustration, 105, 112. - - =Tests= for impurities in water, 153. - - =Tests of steel rivets=, 95. - - =Thimbles=, specification for, 86. - - =Three way cock=, description, 273. - - =Throttle valve=, description, 273. - - =Tin=, melting point, 42. - Conducting power of, 213. - Specific heat of, 214. - Radiating power of, 213. - - =Tissue paper=, radiating power of, 213. - - =Tongs= for boiler makers, 281. - - =Tool box=, description, 22. - - =Tools=, plumber’s, description, 306-309. - Handy for the fire-room, 21. - Used in steam fitting, 269. - Boiler maker’s, 281. - Plumber’s caulking, 308. - - =Torch=, 307. - - =Total heat= of steam, 283. - - =Tough=, definition, 121. - - =Trained= or untrained firemen, difference, 24. - - =Trap=, fish, 205. - - =Treble riveting=, example, 93. - - =Triple draught=, tubular boiler, 82. - - =Trevithick, Richard=, frontispiece. - - =Tube expanders=, 281. - - =Tubes=, how to weld, 264. - Table of bursting and collapsing pressures, 264. - Boiler, illustration of size, 245. - Experiments in holding power, 111. - Table of holding power, 111. - Boiler, table of dimensions, 110. - Leaky, how to repair, 126. - - =Tubes and flues=, sweeping, 39. - - =Tube sheets=, description, 81. - - =Turn-pin=, description, 306. - - =Two flue= steam boiler, 78. - - - =Umbria=, steamer, firing boilers, 32. - - =Unequal riveting=, example, 93. - - =Union=, description, 274. - - =Unit= of chimney measurements, 297. - - =Upright steam boilers=, description, 51. - - =Uptakes= of marine boiler, 64. - - - =Valve=, gate, 273. - Globe, description, 272. - Brine, description, 273. - Pop, description, 184. - Angle, description, 273. - Check, description, 278. - Sentinel, description, 184. - Pressure regulator, 274. - Rotary, description, 273. - Straightway, description, 273. - Throttle, description, 273. - Ball, description, 273. - Chamber, description, 272. - Double beat and double seat, 273. - Swing description, 273. - - =Valve bracket=, description, 272. - - =Valve cock=, description, 272. - - =Valve coupling=, description, 272. - - =Valves=, description, 271. - Safety, description, 187. - Of what material made, 274. - - =Valves=, hinged, description, 272. - Relief, description, 272. - Back pressure, description, 273. - Lifting, description, 274. - - =Valves and cocks=, description, 272. - - =Valve-seat=, description, 272. - - =Vaults= for fuel oil, how to construct, 289. - - =Ventilation=, 265. - - =Vise=, steamfitter’s, 269. - - =Vises=, use of, 21. - - - =Water=, how formed, 143. - Principles relating to, 223. - Principal temperatures of, 224. - Point of maximum density, 224. - The boiling point, 224. - The standard temperature, 224. - pecific heat of, 214. - Boiling point of pure, 37. - Radiating power of, 213. - Conducting power of, 213. - Freezing point, 224. - - =Water=, (sea,) precipitator for, 145. - Boiling point of salt, 37. - - =Water bending= of lead pipe, 304. - - =Water circulation=, 294. - - =Water grate bars=, description, 175. - Gauge cocks, description, 176. - - =Water hammer=, 283. - - =Water meters=, rule for reading, 205. - Description, 203. - - =Water ram=, 284. - - =Water space= of boilers, rule and example, 105. - - =Water table= in locomotive, 35. - - =Water tube= steam boiler, description, 67. - - =Water heater=, noiseless, 312. - - =Water tube steam boiler=, setting of, 239. - - =Watt, James=, 68. - - =Weight= of different standard gallons of water, 225. - Of a column of air, 17. - - =Weldable=, definition, 121. - - =Welding= boiler and other tubes, 264. - - =Wet steam=, 283. - - =Wheelbarrow=, use of, 20. - - =Whistle=, steam, description, 180. - - =Whitewash=, description, 232. - - =Wipe joint=, how to make, 300. - Plumber’s, 298. - - =Wood=, comparative evaporation, 18. - Specific heat of, 214. - As a combustible, 14. - “Hint as to drying,” 14. - - =Wood charcoal=, comparative evaporation, 18. - - =Wood chisel=, 307. - - =Wounds=, treatment of, 310. - - =Writing paper=, radiating power of, 213. - - - =Zig-zag riveting=, example, 93. - - =Zinc=, conducting power of, 213. - Melting point, 42. - Effect on corrosion of boilers, 150. - Use in marine boilers, 162. - Specific heat of, 214. - -[Illustration: Page decoration oil cans] - - - - -MECHANICAL LIST - -[Illustration: - - T - A - Co.] - -=+EDUCATIONAL MANUALS …+= - -—ON— - - ENGINEERING, ELECTRICITY, - MECHANICAL DRAWING, - MACHINE SHOP PRACTICE, - MILLWRIGHTING, APPLIED - MECHANICS, ETC. - -THEO. AUDEL & COMPANY - -——PUBLISHERS—— - -63 FIFTH AVE., NEW YORK - - - - -ERECTING AND OPERATING $3 - -——JUST ISSUED—— - - -[Illustration: - - ROGERS’ ERECTING and OPERATING - _for_ _ENGINEERS, MACHINISTS AND MILLWRIGHTS_ - -AUDEL] - -A PRACTICAL HANDBOOK on Excavations, Foundations, Structures, -Millwrighting, Shafting, Belting, Piping, Boilers, Engines, Installing -Machinery, etc. - -In order to become an expert at the _erection and operation of modern -machinery and appliances_, judgment must be added to execution; now -as judgment cannot be taught in writing, further than in laying down -certain principles of procedure, therefore the book is largely personal. - -The method of instruction followed is to deal with the various subjects -mentioned, each consisting of nearly the same number of pages and -illustrations, indicating the course of study. - -Working Drawings, Foundations, Excavating, Piling and Grillage, Brick -Work, Concrete, Reinforced Concrete, Millwright’s Tools, Steel Square -and its uses, Bridge Work, Structures, Scaffolding and Stagging, -Rigging Knots. 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It is in every way a generously good book both in contents and -manufacture. - -=+PRICE+= $3 =+to any address+=. - - - - -DRAWING AND DESIGN $3 - - -THIS volume is arranged for a comprehensive, self-instruction course -for both shop and drawing room. - -——PLAN OF INSTRUCTION—— - -[Illustration: ROGERS’ DRAWING and DESIGN - -AUDEL] - - Useful Terms and Definitions; Drawing Board, T-Square and Triangles; - Lettering; Shade Lines; Section lining; Geometrical Drawing; - Isometric Projection; Cabinet Projection; Orthographic Projection; - Development of Surfaces; Working Drawings; Tints and Colors; Tracing - and Blue Printing; Reading of Working Drawings; Machine Design; - Physics and Mechanics; Materials Used in Machine Construction; - Screws, Bolts and Nuts; Rivets and Riveted Joints; Power - Transmission; Shafts and Bearings; Belts and Pulleys; Gear Wheels; - Metal Working Machines; Dies and Presses; Drilling and Milling - Machines; The Lathe; Engines and Boilers; Electrical Machines; - Drawing Instruments; Logarithms; Tables and Index. - -Contains 506 pages, illustrated by over 600 cuts and diagrams, very -many of them full page drawings; the book is printed on a very fine -grade of paper; it measures 8-1/2 × 10-1/2 inches and weighs over 3 -pounds; the binding is in black cloth with gold edges and titles; the -volume is made to open freely and is in every way a most complete -up-to-date book. - -=+PRICE+=, $3 =+to any address+=. - - - - -ADVANCED MACHINIST $2 - - -THE trade of the machinist is peculiar in that it is a preparation for -so many positions outside of it. - -It takes a man of good natural ability and of considerable -education—not always from books—to make a first-class machinist; so -that when one is well qualified he is also prepared for many other -openings. - -The aim of this work is to point the way of advancement to those who -become fitted to assume these responsibilities and rewards. - -The advanced machinist is a work of sterling merit, a few of the -hundreds of subjects are here named, but they in no way show the scope -of this work, which must be seen to be appreciated: - -A Course in Machine Shop Mathematics; Various Measuring Instruments -and Their Uses; Screw Cutting; Boring; Milling; Drilling; Grinding; -Punching and Shearing; Bolt Cutting Machinery; Special and Auxiliary -Machines; Shop Management: Work Shop Receipts and Devices, etc., etc. - - The personal character of the book appeals to all in any way - associated in the machinery and allied trades. - -[Illustration: RODGER’S ADVANCED MACHINIST - -AUDEL] - -This book is a companion volume to Progressive Machinist and is uniform -in binding and style, but more advanced in the subject of Machine Shop -Practice, containing about the same number of pages, illustrations, etc. - - PRICE, $2, Postpaid. - - THEO. 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AUDEL & CO., 63 FIFTH AVENUE, NEW YORK, N. Y. - - - - -MOTOR CAR PRACTICE $2 - -A Good Book for Owners, Operators, Repairmen and Intending Purchasers. - -[Illustration: AUTOMOBILES - -SELF PROPELLED VEHICLES - -J.E.HOMANS - -A PRACTICAL TREATISE WITH ILLUSTRATIONS AND DIAGRAMS - -5ᵗʰ EDITION REVISED -] - -THIS work is now the accepted standard on the practical care and -management of motor cars—explaining the principles of construction and -operation in a clear and helpful way, and fully illustrated with many -diagrams and drawings, making it of value to the intending purchaser, -driver and repair man. - -The subjects treat of the needs of the man behind the wheel, and are -presented clearly, concisely and in a manner easy to understand by the -reader, be he a beginner or an expert. - -The treatise on the gasoline engine cannot fail to prove valuable to -anyone interested in explosive motors, which are daily coming to the -front as the readiest and most convenient source of power. - - Contains 608 pages, over 400 diagrams and illustrations, printed on - fine paper, size 5-3/4 by 8-1/2 inches, with generously good binding. - Highly endorsed. This book will be sent to any address in the world, - postpaid, upon receipt of =$2=. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -PUMPS AND HYDRAULICS $4 - -2 PARTS - -IT is with pleasure we call your attention to the recent publication on -pumping machinery. This work, issued under the title of “ROGERS’ PUMPS -AND HYDRAULICS,” is a complete and practical handbook, treating on the -construction, operation, care and management of pumping machinery; -the principles of hydraulics being also thoroughly explained. The -work is illustrated with cuts, diagrams and drawings of work actually -constructed and in operation; the rules and explanations of the -examples shown are taken from everyday practice. No expense has been -spared in the endeavor to make this a most helpful instructor on the -subject, useful to all pump attendants, engineers, machinists and -superintendents. - -[Illustration: -PUMPS AND HYDRAULICS - -ROGERS - -A PRACTICAL TREATISE WITH ILLUSTRATIONS AND DIAGRAMS - -PART ONE - -T A Co. - -PUMPS AND HYDRAULICS - -ROGERS - -A PRACTICAL TREATISE WITH ILLUSTRATIONS AND DIAGRAMS - -PART TWO - -T A Co. -] - -Subjects Treated - -The Air Pump; Air and Vacuum Pumps; Air Compressors; The Air Lift Pump; -The Steam Fire Engine; Miscellaneous Pumps; Mining Pumps; Marine Pumps; -“Sugar-house” Pumps; Circulating Pumps; Atmospheric Pumps; Ammonia or -Acid Pumps; The Screw Pump; Aermotor Pumps; Rotary and Centrifugal -Pumps; Turbine Pumps; Injectors and Ejectors; Pulsometer-Aqua-Thruster; -Pump Speed Governors; Condensing Apparatus; Utilities and Attachments, -Tools, Valves and Piping, Pipes, Joints and Fittings, Useful Notes; -Tables and Data; Glossary of Pump and Hydraulic Terms; Elementary -Hydraulics; Flow of water Under Pressure; Water Pressure Machines, -Water Wheels; Turbine Water Wheels; Turbine Pumps; Water Pressure -Engines; Hydraulic Motors; Hydraulic Apparatus; Hydraulic Jack; -Hydraulic Press; Hydraulic Accumulator; Hydraulic Ram; Pumps as -Hydraulic Apparatus; Classification of Pumps; Hand Pumps; Power Pumps; -Belted Pumps; The Electric Pump; The Steam Pump; The Duplex Pump; -Underwriter Fire Pump; Specifications of the National Board of Fire -Underwriters Relating to Duplex Fire Pumps. - -These two volumes of nearly nine hundred pages, illustrated with -about seven hundred wood cuts, are admirable specimens of bookmaking; -they are printed on fine white paper in large clear text, with ample -margins, and bound in black vellum cloth with titles and tops in gold. -In size they are six by nine inches. - -——PRICE, $4, DELIVERED—— - - - - -MARINE ENGINEERING $2 - - -[Illustration: - -QUESTIONS AND ANSWERS FOR MARINE ENGINEERS - -LUCAS - -HAWKINS - -PRICE $2. - -AUDEL & CO - -WITH CHAPTER ON =+BREAKDOWNS AT SEA+= -] - -THIS treatise is the most complete published for the practical -engineer, covering as it does a course in mathematics, the management -of marine engines, boilers, pumps, and all auxiliary apparatus, =+the -accepted rules for figuring the safety-valve+=. - -The book is divided into two parts: Part I, Construction: Part II, -Operation; it contains 700 pages. - -The volume is illustrated with plate drawings, diagrams and cuts, -having an Index with more than =+1,000 ready references, 807 Questions -on practical marine engineering are fully answered and explained+=. - -Size is 5-3/4 × 8-1/2 inches, 1-1/2 inches thick, and weighs nearly -three pounds, strongly and durably bound in rich green cloth, with full -gilt edges, and is the accepted standard on Marine Engineering. - -Price =$2=, sent free to any address in the world. - -=+Money will be refunded if not entirely satisfactory.+= - - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -MECHANICAL DRAWING $2 - - -THE work has been carefully arranged according to the fundamental -principles of the art of drawing, each theme being clearly illustrated. -=+A list of the subjects are given below:+= - -[Illustration: HAWKINS MECHANICAL DRAWING - -HAWKINS SELF HELP MECHANICAL DRAWING FOR HOME STUDY -] - -Chalk Work; Preliminary Terms and Definitions; Freehand Drawing; -Geometrical Drawing; Drawing Materials and Instruments; Mechanical -Drawing; Penciling; Projection; “Inking in” Drawings; Lettering -Drawings; Dimensioning Drawings; Shading Drawings. - -Section Lining and Colors; Reproducing Drawings; Drawing Office Rules; -Gearing; Designing Gears; Working Drawings; Reading Working Drawings; -Patent Office Rules for Drawings; Useful Hints and Points; Linear -Perspective; Useful Tables; Personal, by the Editor. - -The book contains 320 pages and 300 illustrations, consisting largely -of diagrams and suggestive drawings for practice. It is bound in dark -green cloth with full gold edges and titles; it is printed on fine -paper, size 7 × 10 inches; it weighs 33 oz., and will fit into any -engineer’s or mechanic’s library to good advantage. - -PRICE, $2, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -ELECTRICITY FOR ENGINEERS $2 - -THE introduction of electrical machinery in almost every -power plant has created a great demand for competent -engineers and others having a knowledge of electricity -and capable of operating or supervising the running of electrical -machinery. To such persons this pocket-book will be -found a great benefactor, since it contains just the information -that is required, _explained in a practical manner_. - -[Illustration: -HAWKINS’ NEW CATECHISM OF ELECTRICITY. - -HAWKINS’] - -=+Plan of Study+= - -The following is a partial list of the topics discussed and illustrated: - -Conductors and Non-Conductors: Symbols, abbreviations and definitions -relating to electricity; The Motor; The Care and Management of the -Dynamo and Motor. - -Electric Lighting; Wiring; The rules and requirements -of the National Board of Underwriters in full; Electrical Measurements. - -The Electric Railway; Line Work; Instruction and Cautions for Linemen -and the Dynamo Room; Storage Batteries; Care and Management of the -Street-Car Motor; Electro Plating. - -The Telephone and Telegraph; The Electric Elevator; Accidents and -Emergencies, etc., etc. - -One-third of the whole book has been devoted to the explanation and -illustrations of the dynamo, and particular directions relating to its -care and management;—all directions being given in the simplest and -kindly way to assist rather than confuse the learner. - -It contains 550 pages with 300 illustrations of electrical appliances; -it is bound in heavy red leather, (size 4-1/2 × 6-1/2 for the pocket), -with full gold edges and is a most attractive handbook for Electricians -and Engineers. - -PRICE, $2, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -ENGINEERS’ EXAMINATIONS $2 - - -THIS work is an important aid to engineers of all grades, and is -undoubtedly the most helpful ever issued relating to a safe and sure -preparation for examination. It presents in a condensed form the most -approved practice in the care and management of Steam Boilers, Engines, -Pumps, Electrical and Refrigerating Machines, also a few plain rules of -arithmetic with examples of how to work the problems relating to the -safety valve, strength of boilers and horse power of the Steam Engine -and Steam Boiler. - -It contains various rules, regulations and laws of large cities for -the examination of boilers and the licensing of engineers. It contains -the laws and regulations of the United States for the examination and -grading of all marine engineers. - -The book gives the underlying principles of steam engineering in plain -language, with very many sample questions and answers likely to be -asked by the examiner. - -It also gives a short chapter on the “Key to Success” in obtaining -knowledge necessary for advancement in engineering. - -[Illustration: - -_HAWKIN’S AIDS._ - - ENGINEERS’ EXAMINATIONS - —WITH— - QUESTIONS AND ANSWERS - -] - -This helpful volume contains 200 pages of valuable information not -elsewhere obtainable; it is bound in rich red leather with full gold -edges and titles; it measures 5 × 7-1/2 inches and weighs twenty-two -ounces. - -PRICE, $2, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -STEAM BOILER PRACTICE $2 - - -THIS book of instruction on boiler-room practice will be of great help -to firemen, engineers and all others who wish to learn about this -important branch of Steam Engineering. - -It treats on materials, coals, wood, coke, and oil and gas, fuels, -etc., their composition, properties, combustive value, also on -combustion and evaporation. - -Giving the practical rules to be observed in firing with various fuels, -management of steam boilers, prevention of foaming; tools and fire -irons; covering stationary, marine and locomotive boilers. - -It enumerates sixty important points of cautions to be observed in the -proper management of boilers. - -It contains a description of and full treatise on stationary, marine -and locomotive boilers, and the historical development of boilers; -specifications for boilers; riveting; bracing; rules for finding -pressure or strain on bolts. - -It gives inspectors rules relating to braces in steam boilers. Also -rules and tables for calculating areas and steam and water space of -boilers. - -It treats on boiler tubes, construction and drawing of boiler sections; -defects and necessary repairs; inspection of steam boilers; mechanical -stokers’ corrosion and scale, boiler compounds, feed water heaters, -injectors, pumps, boiler settings; pipes and piping; steam heating, -chemistry of the furnace; boiler making; plumbing, and hundreds of -other useful subjects. - -It states several plain rules for the calculation of safety valve -problems and those sanctioned by the U. S. inspectors. - -[Illustration: - - MAXIMS AND INSTRUCTIONS FOR THE BOILER ROOM - N. HAWKINS ME - AUDEL & CO. - -] - -The volume has 330 pages and 185 illustrations and diagrams. It is 6 -× 8-1/2 in. in size and weighs 28 ounces. The binding is uniform with -that of the “Calculations” and “Catechism of the Steam Engine,” being -bound in heavy green cloth, with ornamental titles and edges in gold. - -PRICE, $2, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -CALCULATIONS FOR ENGINEERS $2 - - -THE Hand Book of Calculations is a work of instruction and reference -relating to the steam engine, the steam boiler, etc., and has been said -to contain every calculation, rule and table necessary to be known by -the Engineer, Fireman and a steam user. - -Giving a complete course in Mathematics for the Engineer and steam -user; all calculations are in plain arithmetical figures, so that the -average man need not be confused by the insertion of the terms, symbols -and characters to be found in works of so-called “higher mathematics.” - -Mechanical Powers; Natural or Mechanical Philosophy; Strength of -Materials; Mensuration; Arithmetic; Description of Algebra and Geometry. - -Tables of Weights, Measures, Strength of Rope and Chains, Pressures -of Water, Diameter of Pipes, etc.; The Indicator, How to Compute; The -Safety Valve, How to Figure; The Steam Boiler; The Steam Pump; Horse -Powers, How to Figure for Engines and Boilers; Steam, What It Is, etc. - -Index and Useful Definitions. - -[Illustration: - -HAND BOOK OF CALCULATION FOR ENGINEERS - -H. HAWKINS ME - -AUDEL & CO. - -] - -This work contains 330 pages and 150 illustrations; it is durably and -handsomely bound, uniform in style and size with the “Instructions for -the Boiler Room” and the “Catechism of the Steam Engine;” it has gold -edges and titles, and weighs over 28 ounces. - -PRICE, $2, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -STEAM ENGINE PRACTICE $2 - - - “It has been well said that engineers are born, not made; those in - demand to fill the positions created by the great installations of - power-producing machinery now so common, are men who are familiar - with the contents of good books, and as well, are the product of a - hard bought practical experience.” - -THIS work is gotten up to fill a long-felt need for a practical book. -It gives directions for running the various types of steam engines that -are to-day in the market. - -A list of subjects, which are fully yet concisely discussed, are as -follows: - -Introduction; The Steam Engine; Historical Facts Relating to the -Steam Engine: Engine Foundations; The Steam Piston; Connecting Rods; -Eccentric; Governor; Materials; Workmanship; Care and Management; -Lining up a Horizontal or Vertical Engine; Lining Shafting; Valve -Setting; Condensers; Steam Separators; Air, Gas, and Compressing -Engines: Compounding; Arithmetic of the Steam Engine; Theory of the -Steam Engine; Construction. - -There also is a description of numerous types of the engines now in -operation, such as the Corliss, Westinghouse, and many others. - -The book also treats generously upon the Marine, Locomotive and Gas -Engines. - -[Illustration: - -NEW CATECHISM OF THE STEAM ENGINE - -N. HAWKINS ME - -AUDEL & CO. -] - -This is a rarely fine book, handsomely bound in green silk cloth, with -full gold edges and titles; it contains 440 pages, 325 illustrations; -in size it is 6 × 8-1/4 inches, and weighs 2 pounds. - -PRICE, $2, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -STEAM ENGINE INDICATOR $1 - - -THE work is designed for the use of erecting and operating engineers, -superintendents, and students of steam engineering, relating, as it -does, to the economical use of steam. - -The following is a general outline of the subjects defined, illustrated -and presented most helpfully in the book. - -Preparing the Indicator for use; Reducing Motions; Piping up Indicator; -Taking Indicator Cards; The Diagram; Figuring Steam consumption by the -diagram; Revolution Counters; Examples of Diagrams; Description of -Indicators; Measuring Diagram by Ordinates; Planimeters; Pantagraphs, -Tables, etc. - -He who studies this work thoughtfully will reap great benefit and -will find that there is nothing difficult or mysterious about the use -of the Steam Engine Indicator. This knowledge is necessary to every -well-informed engineer and will undoubtedly be highly appreciated and a -stepping-stone toward promotion and better things. - -[Illustration: - - PRACTICAL TREATISE - —ON THE— - STEAM ENGINE INDICATOR - -HAWKINS INDICATOR. -] - -The work is fully illustrated, handsomely bound, and is in every way a -high grade publication. - -----PRICE, $1.00---- - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -TELEPHONE ENGINEERING $1 - - -THE “A B C of the Telephone” is a book valuable to all persons -interested in this ever-increasing industry. No expense has been spared -by the publishers, or pains by the author, in making this the most -comprehensive handbook ever brought out relating to the telephone. - -TABLE OF CONTENTS - -=+29 CHAPTERS+= - -The Telephone Apparatus and its Operation; A Brief Survey of the -Theory of Sound, Necessary to an Understanding of the Telephone; A -Brief Survey of the Principles of Electricity; Electrical Quantities; -History of the Speaking Telephone; Later Modifications of the Magnet -Telephone; The Carbon Microphone Transmitter; The Circuits of a -Telephone Apparatus; The Switch Hook and its Function in Telephone -Apparatus; The Switchboard and the Appliances of the Central Station; -The Operator’s Switch Keys and Telephone Set; Improved Switchboard -Attachments; Switchboard Lamp Signals and Circuits; The Multiple -Switchboard; Locally Interconnected or Multiple Transfer Switchboard; -Exchange Battery Systems; Party Lines and Selective Signals; Private -Telephone Lines and Intercommunicating Systems; Common Return Circuits; -Private Telephone Lines and Intercommunicating Systems; Full Metallic -Circuits; Large Private Systems and Automatic Exchanges; Devices for -Protecting Telephone Apparatus from Electrical Disturbances; The -General Conditions of Telephone Line Construction; Telephone Pole -Lines; Wire Transportations on a Pole Line. Telephone Cables and their -Use in Underground and Pole Lines; Circuit Balancing Devices; The -Microtelephone; Wireless Telephony; Useful Definitions and Hints on -Telephone Management. - -=+WITH READY REFERENCE INDEX+= - -[Illustration: - -HOYMAN’S A·B·C OF THE TELEPHONE - -A PRACTICAL TREATISE WITH ILLUSTRATIONS AND DIAGRAMS - -$1 - - AUDEL & CO. - NEW YORK -] - -The volume contains 375 pages, 268 illustrations and diagrams; it is -handsomely bound in black vellum cloth, and is a generously good book -without reference to cost. - -PRICE, $1, Postpaid. - -THEO. AUDEL & CO., 63 FIFTH AVENUE, NEW YORK - - - - -Hawkins’ Dictionary,_$3.50_ - - -=+THIS volume is the most useful book in Mechanical Literature.+= - -If constantly referred to will enable the student to acquire a correct -knowledge of the words, terms and phrases in use in Mechanical -Engineering and its various branches. - -=+Its greatest value lies in this:+= that no man representing the -mechanical profession can find excuse for not knowing the use and -meaning of the terms used in his work. - -=+HAWKINS’ MECHANICAL DICTIONARY+= explains and defines in plain -language the use of all words and terms now used or heretofore used in -the =+Mechanic Arts, Trades and Sciences+=. - -=+It is an unequaled reference work+=, and is the one book of permanent -value no student or expert should dispense with. Complete from A to Z. -Highly endorsed. - -[Illustration: - -HAWKINS’ MECHANICAL DICTIONARY - -A CYCLOPEDIA OF WORDS, DATA AND PHRASES -] - -Contains 704 pages, handsomely bound, price $3.50 postpaid. -Satisfaction guaranteed. - - - - - * * * * * * - - - - -Transcriber’s note: - -The original spelling, hyphenation, accentuation and punctuation has -been retained, except for apparent typographical errors. - -A table of contents has been added by the transcriber following the -preface. - -Index entry ‘Evans, Robt., 11.’ corrected to read ‘Evans, Oliver, viii.’ - -In the chapter ‘CHIMNEYS AND DRAUGHT’ 12th para:- - -‘… having about 1 square foot of heating surface to 45 square feet of -heating surface.’ - -This has been changed to read:- - -‘… having about 1 square foot of grate area to 45 square feet of -heating surface.’ - -The references to a ‘Six Inch Flue Boiler’ in Fig. 32 and the Index may -mean ‘Six Flue Boiler’, these instances have not been changed. - -In the chapter ‘CHEMISTRY OF THE FURNACE’, the opening paragraph -has a number of apparent typographical errors relating to names of -substances. These have been left as printed and are:- - - naphthaline typographical error for naphthalene - alizarine „ „ „ alizarin - toludine „ „ „ toluidine - anthracine „ „ „ anthracene - toluches „ „ „ toluene - saccharine „ „ „ saccharin - - - -***END OF THE PROJECT GUTENBERG EBOOK MAXIMS AND INSTRUCTIONS FOR THE -BOILER ROOM*** - - -******* This file should be named 53139-0.txt or 53139-0.zip ******* - - -This and all associated files of various formats will be found in: -http://www.gutenberg.org/dirs/5/3/1/3/53139 - - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the United -States without permission and without paying copyright -royalties. 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