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:

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.

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.

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.

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.

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.

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.

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.

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.

In this illustration, A exhibits double, inside and outside Calipers; B, adjustable outside Calipers; C, inside; and D outside, plain calipers.