Read Ebook: Maxims and Instructions for the Boiler Room Useful to Engineers Firemen & Mechanics; Relating to Steam Generators Pumps Appliances Steam Heating Practical Plumbing etc. by Hawkins N Nehemiah

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INTRODUCTION.

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.

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:

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 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.

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 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.

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.

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