Chapter III: Part 3

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There are not many underground formations where wells should be located close together. Such wells may affect or rob each other, and it is usually best to spread them out on a line across what is known to be the underground flow. Some finely creviced or tight rock formations have a strong head with but little capacity, and wells in such formations, if pumped hard, yield but little additional water. They should be scattered and pumped moderately, maintaining a low and economical lift. In other cases, one well in a group will give as much water as all together, and more territory must be drawn on.

_The Pohle system of elevating liquids_ is shown in Fig. 377. The process “consists in submerging a portion of an open-ended eduction-pipe in a body of the liquid to be raised and continuously introducing into the liquid within the lower part of the pipe a series of bubbles of compressed gaseous fluid containing enough of the fluid to expand immediately across the pipe and fill the same from side to side, forming pipe-fitting piston-like layers at or just above the point of their entrance into the pipe, whereby the column of liquid rising in the pipe after the forcing out of the liquid first standing in the latter is subdivided by the gaseous fluid into small portions before it reaches the level of the liquid outside of the pipe, and a continuously upward-flowing series of well-defined alternate layers of gaseous fluid and short layers of liquid is formed and forced up the pipe.”

The figures represent the apparatus in a state of action pumping water, the shaded sections within the eduction-pipe, W, representing water-layers and the intervening blank spaces air-layers.

At and before the beginning of pumping, the level of the water is
the same outside and inside of the discharge-pipe, W,—incidentally,
also, in the air pipe. Hence the vertical pressures per square
inch are equal at the submerged end of the discharge pipe. When,
therefore, compressed air is admitted into the air pipe, _a_, it must
first expel the incidental standing water before air can enter the
eduction-pipe, W. When this has been accomplished, the air-pressure
is maintained until the water within the eduction-pipe has been
forced out, which it will be in one unbroken column, free from
air-bubbles.

When this has occurred the pressure of the air is lowered or its bulk
diminished and adjusted to a pressure just sufficient to overcome
the external water-pressure. It is thus adjusted for the performance
of regular and uniform work, which will ensue with the inflowing air
and water, which adjust themselves automatically in alternate layers
or sections of definite lengths and weights. It will be seen in the
figures that the lengths of the water-columns (shaded) and air (blank
spaces) 1 and 1 are entered at the right of the discharge-pipe,
W; also, that under the pressure of two layers of water 1 and 2,
the length of the air column 2 is 6.71 feet long, and so on. The
lengths of aggregate water columns and the air columns which they
respectively compress are also entered on the right of the water-pipe.

On the left of the water-pipe are entered the pressures per square
inch of these water columns or layers. Thus the pressure per square
inch of column 1 is seen to be 1.74 pounds; that of 2, consisting of
two columns or layers 1 and 2 each 4.02 feet long, to be 3.49 pounds,
and that of 10, consisting of nine columns or layers of water 1 to 9,
inclusive, each 4.02 feet long, and one of 3.80 feet in length (viz.,
layer 10) to be 17.35 pounds, and the aggregate length of the layers
of water is 39.98 feet in a total length of ninety-one feet of pipe.

It will be noted that the length of pipe below the surface of the
water in the well is 55.5 feet, and that the difference between
this and the aggregate length of the water layers (39.98) is 15.52
feet—that is, on equal areas the pressure outside of the pipe is
greater than the pressure on the inside by the weight due this
difference of level, which is 47.65 pounds for the end of the
discharge pipe.

It is this difference of 15.52 feet, acting as a head that supplies
the water pipe, which puts the contents of the pipe in motion, and
overcomes the resistance in the pipe. In general the water layers are
equal each to each, and the pressure upon any layer of air is due to
the number of water layers above it.

Thus the pressure upon the bottom layer of air 10 in the figure is
due to all the layers of water in the pipe (17.35 pounds), and the
pressure upon the uppermost layer of air 1 is due to the single
layer of water, 1, at the moment of its discharges beginning—viz.,
1.74 pounds per square inch. As this discharge progresses this is
lessened, until at the completion of the discharge of the water layer
the air layer is of the same tension as the normal atmosphere.

_The air pipe_ is connected with an air receiver on the surface, which is at or near the engine room, in which there is _an air compressor_. This air pipe is provided with a valve on the surface. Before turning on the air the conditions in the well show water at the same level on the outside and inside of the eduction-pipe. At the first operation there must be sufficient air pressure to discharge the column of water which stands in the eduction-pipe.

This goes out _en masse_, after which the pump assumes a normal condition, the air pressure being lowered and standing at such a point as corresponds with the normal conditions in the well. This is determined by the volume of water which the well will yield in a certain time and the elevation to which the water is discharged.

NOTE.—This extended description of the principles upon which an air
lift operates—with its illustrations—is drawn almost word for word
from the original patent claims of Dr. Pohle. The occupation of
the space in the work is justified by the increasing importance of
this system of water supply and its practical applications in the
industrial world.

Year by year the world’s visible supply of coal—so long stored and
hidden away in the earth’s crust awaiting the advent of man—is
diminishing, next will dawn the age of air and water with electric
transmission.

After the standing water column has been thrown off by the pressure the air rises through the water reduces its weight, with the result that the water is expelled as fast as the well supplies it, _the water outside the pipe, acting as a head, flows into the discharge pipe by the force of gravity_.

The machinery necessary for a system of pumping comprises, 1, _an air compressor_; 2, a receiver to store and equalize the pressure; 3, the head piece and foot piece for the well; and, 4, the necessary piping for the air supply and water discharge.

With an available supply of air under pressure _the pump proper consists of simply a water discharge and air pipe_, the latter arranged and properly controlled to inject air into the former at the point of proper submersion. It is readily seen that the apparatus is so simple that as a pump it cannot get out of order; in cases, where mud, sand or gritty material is encountered, it will handle such matter _with the water_ and without injury to the system, as nothing comes in contact with the moving parts.

Absence of all obstructing mechanism in the wells allows each to be operated to its full capacity. Production, therefore, does not depend upon the pump, but rather upon the capacity of the well to yield water; the natural yield of wells is often increased by this process of using compressed air admitted close to the bottom of the discharge pipe, the water is set in motion at a considerable depth, and by this action the well is “cleaned.”

_Purification is effected by aeration during the process of pumping_, the absorption of air by the water preventing the formation of unsanitary growths.

_Three styles of well heads_ are shown in Figs. 383, 384 and 385.

_The deflector head_, Fig. 383, is attached to the well casing or discharge pipe by standards. This form of head piece is generally used where the water is to be raised to the surface, or just below the surface into a tank, where the air is allowed to separate itself, and the water flows to some central collecting reservoir, where it is used or forced by means of an ordinary pump to a higher elevation. The head piece offers no obstruction to the discharged water.

_The offset discharge_, Fig. 384, is adapted to situations where the water is to be pumped by air direct from the well to some elevation above the well.

_The elbow discharge_, Fig. 385, shows the common form of well head known as the elbow head, adapted to be used either as a cap for the well casing itself, or used in connection with a suitable discharge pipe.

_The foot piece, or nozzle_, which regulates the admission of air to the discharge pipe at the point where the air comes in contact with the water, thereby makes it possible to carry air at full pressure to the end of the air pipe, and utilizes the energy due to the velocity of the discharged air.

_After a well is once regulated or balanced_ there is but little occasion to move the adjusting wheel or valve, the starting and stopping of the flow of any particular well being accomplished by means of an ordinary valve or plug cock on the air pipe at or adjacent to the well.

_One Central Station of suitable capacity will operate several wells no matter how far apart._ The necessity of maintaining a number of separate pumping plants is thus done away with, and in taking a supply of water from an underground source the wells can be located without reference to the power plant, and at such distances apart as will best maintain the highest average pumping level.

Although the principle of the action governing all pumps of this description is so simple, there are a number of factors having a direct influence upon the performance of the pump, which have been expressed in the following terms by a well-known expert:

(_a_) Depth of submersion of point of air discharge below still water
surface.

(_b_) Velocity of water at point of air discharge.

(_a_) and (_b_) determine the necessary air pressure. If (_a_) is
constant, the pressure decreases when (_b_) increases.

(_c_) Area of main, or water discharge pipe.

(_d_) Net lift to point of water discharge, including velocity head
at that point.

(_e_) Volume of air (at atmospheric pressure) discharged per unit of
time.

(_f_) Ratio of expansion of air as it rises through the main pipe;
(_f_) may be considerably modified by the temperature of the water.

(_g_) Total volume of air in main pipe at any instant. This
determines the specific gravity of the discharging column.

(_h_) The volume of each individual bubble within the main.

Letters are for reference only and do not indicate the order of
importance nor of effect.

It was at first supposed that in all Air Lift cases the water was discharged because of the aeration of the water in the eduction-pipe, due to the intimate co-mingling of air and water. Bubbles of air rising in a water column not only have a tendency to carry particles of water with the air, but the column is made lighter, and, with a submergence or weight of water on the outside of the eduction-pipe, there would naturally be a constant discharge of air and water. This is known as the Frizell System, and where the lifts are moderate—that is, where the water in the well reaches a point near the surface—it is very likely that the discharge is due to simple aeration.

Most air lift propositions are deep-well cases—that is, the water is lifted a distance greater than 25 feet; and just in proportion as the lift is increased do we get away from the aerated form idea, and so when the air pressure is greater than the head of water, a certain volume of compressed air is received into the eduction-pipe, the water in this pipe is at that time moving rapidly upward; that is, its momentum has been established. Hence the air takes up this velocity and goes upward with the water from the energy received from the elasticity of the air due to its compressor.

A practical example of the successful working of an air compressor for raising water from a driven well 319 feet is described and illustrated by the _Practical Engineer_ as shown in the sketch, Fig. 386.

The air compressor forces the air down the inside pipe, which is 1-1/4″ in diameter. The outside pipe, which is 3″ in diameter, has its lower end submerged in the well. The compressed air forces a rising column of air mingled with water in the outer pipe to the supply tanks, which are situated at the top of the building.

_Direct Air Pressure Pumps._ This term is applied to that class of pumps in which the liquid is taken into an air tight vessel and then driven out through pipes to a higher level by the application of compressed air directly on the surface of the liquid in the tank, thus dispensing with cylinders, pistons, valves, glands, etc., of the more common class of pumps.

Fig. 387 shows the parts of the pump; its operation is as follows: Suppose the compressor to be in operation and the switch set as in the figure; the air will be drawn out of the right tank and forced into the left tank, and in so doing will draw water into the former and force it out of the latter. The charge of air in the system is so adjusted that when one tank is emptied the other is filled, and at that moment the switch will be automatically thrown, reversing the pipe connections and thereby reversing the action in the tanks.

_The switch_ is a simple mechanism placed on the air pipes near the
compressor. It can be automatically operated in one of three ways:

_First_, by means of the suction which occurs in the intake pipe to
the compressor, when water is drawn above its outside level in one of
the tanks. The details of the mechanism to utilize this suction are
very simple.

_Second_, by a mechanism, that will throw the switch at some assigned
number of strokes of the compressor, the proper number being that
which will empty one tank and fill the other. This can be closely
computed beforehand and can be determined exactly by test when
commencing operation and the switch adjusted accordingly.

_Third_, by an electrically controlled mechanism, the circuit being
made and broken by a pressure gauge on the intake of the compressor.

The Pneumatic Engineering Co. are the makers of this apparatus, named _the Harris System_ of raising water by direct pressure.

THE STEAM
FIRE ENGINE

THE STEAM FIRE ENGINE.

The steam fire engine is practically a portable pumping engine. _It is in all respects a complete water works on a small scale_, hence, a modern apparatus must, within itself, and each part working harmoniously with every other part, contain several complex mechanisms. This will readily appear by a study of the several succeeding illustrations; the first, which in the figure below exhibits a “view” of a complete machine.

(See page 109.)]

Modern steam fire engines are classified as to “size,” as “double extra first,” etc.; their capacities and weights are given approximately in the following

TABLE.

The foregoing list of the sizes, capacities, etc., of the fire apparatus now in general use, affords a very good comparison between it and that which has, little by little, progressed for two thousand years to its present high plane. _The application of electric power to the operation of the pumps_ and the propulsion of the apparatus is yet in too elementary a stage for present discussion in a work of this scope for—

It is essential that the machinery relied upon for fire protection should at all times be ready for instantaneous and effective service; this, because both life and vast property interests are at stake, _hence of all machines made, the modern steam fire engine is produced with a niceness of finish and accuracy of fit equaled by no other_, when size is considered; it approaches towards the perfection seen in the mechanism of a fine watch.

This degree of excellence has been arrived at by successive steps. The illustration on page 92, Fig. 388 exhibits the fire-fighting tools of the early Romans and similar apparatus was used in England as late as the fifteenth century. The implements shown are a syringe, a sledge hammer, two fire hooks and three leathern buckets conveniently arranged against a wall. _The owners of houses or chimneys that took fire were fined_; and men were appointed to watch for fires and give the alarm. In 1472 a night bellman was employed in Exeter to alarm the inhabitants in case of fire, and in 1558, leathern buckets, ladders and crooks, were ordered to be provided for the same city; no application of the pump seems to have been then thought of.

Syringes continued to be used in London till the latter part of the 17th century, when they were superseded by more improved machines. They were usually made of brass and held from two to four quarts. The smaller ones were about two feet and a half long, and an inch and a half in diameter; the bore of the nozzles being half an inch. _Three men_ were required to work each, which they achieved in this manner: one man on each side, grasped the cylinder with one hand and the nozzle with the other; while the third man worked the piston! Those who held the instrument plunged the nozzle into a vessel of water, the operator then drew back the piston and thus charged the cylinder, and when it was raised by the bearers into the required position, he pushed in the piston and forced, or rather endeavored to force, the contents upon the fire.[A]

[A] NOTE.—We are told that some of these syringes are preserved in one or two of the parish churches. It can excite no surprise that London should have been almost wholly destroyed in the great fire of 1666, when such were the machines upon which the inhabitants chiefly depended for protecting their property and dwellings. If the diminutive size of these instruments be considered, the number of hands required to work each, beside others to carry water and vessels for them, the difficulty and often impossibility of approaching sufficiently near so as to reach the flames with the jet, the loss of part of the stream at the beginning and end of each stroke of the piston, and the trifling effect produced—the whole act of using them, appears rather as a farce. These primitive devices were known as “hand squirts.”

Figs. 390 and 391 show an early form of syringe. A description of it translated from the original Greek, written by Hero of the ancient city of Alexandria, reads thus—“A hollow tube of some length is made, A, B; into this another tube, C, D, is nicely fitted, to the extremity of which is fastened a small plate or piston; at, D, is a handle, E, F. Cover the orifice, A, of the tube, A, B, with a plate in which an extremely fine tube, G, H, is fixed, its bore communicating with A, B, through the plate—as a vacuum is thus produced in A, B, something else must enter to fill it, and as there is no other passage but through the mouth of the small tube we shall of necessity draw up through this any fluid that may be near.”

Fig. 392 is a copy of an old engraving (A.D. 1568) which shows an “engine” of this type sufficiently enlarged to contain a barrel or more of water and as a matter of necessity, placed on a carriage.

To eject the water uniformly, the inventor moved the piston by a screw; and when the cylinder was emptied, it was refilled through the funnel by an attendant, as the piston was drawn back by reversing the motion of the crank. When recharged, the stop cock in the pipe of the funnel was closed and the liquid forced out as before. As flexible pipes of leather, the “ball and socket” and “goose-neck” joints had not been introduced, some mode of _changing the direction of the jet_ of this enormous syringe was necessary. To effect this, it is represented as suspended on pivots, fastened in two upright posts: to these are secured (see figure) two semi-circular straps of iron, whose centers coincide with the axis, or pivots, on which the syringe is balanced. A number of holes are made in each, and are so arranged as to be opposite each other. A bolt is passed through two of these, and also through a similar hole, in a piece of metal, that is firmly secured to the upper part of the open end of the cylinder; and thus holds the latter in any required position. The iron frame to which the box or female part of the screw is attached, is made fast to the cylinder; and it is through a projecting piece on the end of this frame that the bolt is passed. By these means, any elevation could be given to the nozzle, and the syringe could be secured by passing the bolt through the piece just mentioned, and through the corresponding holes in the straps. When a _lateral_ change in the jet was required, the whole machine was moved by a man at the end of the pole, as in the figure. Jointed feet were attached to the frame which were let down when the engine was at work.

Fig. 393 shows an engine for extinguishing fires, which has come down to us from the times of Hero, who thus describes it:

NOTE.—The siphons used in conflagrations are made as follows. Take
two vessels of bronze, A B C D, E F G H (Fig. 393), having the
inner surface bored in a lathe to fit a piston (like the barrels of
water-organs), K L, M N, being the pistons fitted to the boxes. Let
the cylinders communicate with each other by means of the tube, X O
D F, and be provided with valves, P, R, such as have been explained
above, within the tube, X O D F, and opening outwards from the
cylinders. In the bases of the cylinders pierce circular apertures,
S, T, covered with polished hemispherical cups, V Q, W Y, through
which insert spindles soldered to, or in some way connected with,
the bases of the cylinders, and provided with shoulders at the
extremities that the cups may not be forced off the spindles. To the
center of the pistons fasten the vertical rods, S E, S E, and attach
to these the beam A´ A´, working, at its center, about the stationary
pin, D, and about the pins, B, C, at the rods, S E, S E. Let the
vertical tube, S´ E´, communicate with the tube, X O D F, branching
into two arms at, S´, and provided with small pipes through which to
force up water, such as were explained above in the description of
the machine for producing a water-jet by means of the compressed air.

Now, if the cylinders, provided with these additions be plunged into
a vessel containing water, I J U Z, and the beam, A´ A´, be made
to work at its extremities, A´, A´, which move alternately about
the pin, D, the pistons, as they descend, will drive out the water
through the tube, E´ S, and the revolving mouth, M´. For when the
piston, M N, ascends it opens the aperture, T, as the cup, W Y,
rises, and shuts the valve, R; but when it descends it shuts, T, and
opens, R, through which the water is driven and forced upwards. The
action of the other piston, K L, is the same. Now the small pipe, M´,
which waves backward and forward, ejects the water to the required
height but not in the required direction, unless the whole machine be
turned round; which on urgent occasions is a tedious and difficult
process. In order therefore, that the water may be ejected to the
spot required, let the tube, E´ S´, consist of two tubes, fitting
closely together lengthwise, of which one must be attached to the
tube, X O D F, and the other to the part from which the arms branch
off at, S´; and thus, if the upper tube be turned round, by the
inclination of the mouthpiece, M´, the stream of water can be forced
to any spot we please. The upper joint of the double tube must be
secured to the lower to prevent its being forced from the machine by
the violence of the water. This may be effected by holdfasts in the
shape of the letter L, soldered to the upper tube, and sliding on a
ring which encircles the lower.

FIG. 394.

(See page 109.)
]

Heron or Hero was an Alexandrian mathematician of the 3d Century B. C. He was the inventor of “Hero’s Fountain” in which a jet of water was maintained by condensed air and of a machine acting upon the principle of Barker’s Mill, in which the motion was produced by steam. _Fragments of his works on mechanics have been preserved_ for more than 2000 years.

Lack of space forbids following, as could be done, the growth of the modern steam fire engine from these primitive beginnings to its present high point of excellence and widely extended use. Wherever civilized men are gathered into towns and cities there can be found this admirable mechanism affording protection to both life and property.

The Working Parts,
The Boiler, and
Its facilities for Transportation are the three essential parts of
the one mechanism which combined, form the steam fire engine. In
brief reference to the last qualification, it may be said that these
engines are drawn by hand, by one or more horses, or other animals and
_are self-propelled by both steam and electric power_; again the hose
carriage can be drawn by hand, by horses or can be attached to the
engine.

_The main working parts of the machine_ can be easily divided into two parts, _the engine_ and _the pump_.

The boiler in all its details has been designed to meet the requirements peculiar to the fire service and needs a full explanation with illustrations.

_The auxiliary appliances_ found necessary for the operation of the modern steam fire engine are large in number; this is owing to the fact that the machine combines within itself so complete a system for extinguishing fires. _The supplies_ needed for its maintenance and use are also in proportion, as to quantity and variety, to its complex make up.

_The boiler_, which is generally of the upright semi-water tube type, is combined with the engine by means of a strong iron frame, which carries all the appliances as well as the driver’s seat, and also forms the body of the truck.

FIG. 395.]

_The pumps_ may be of the reciprocating or rotary type, and are generally placed in front of the boiler. If of the reciprocating type, two pumps are placed alongside each other, and are operated either by a double slide valve or piston valve engine.

_The piston rods_ connect directly with the plunger rods and are also connected to a crank shaft by means of either connecting rods or yokes, the cranks being set at right angles, so that one pump is always acting, while the other passes the dead center, thus giving a practically steady stream.

_The engine exhausts into the stack_, which gives the necessary draft. Some engines are equipped with a boiler feed pump, others only depend upon an injector, or feed directly from the main pump. _The coal box_, which also forms a platform for the engineer to stand upon while under way, is placed back of the boiler.

_All engines are equipped with two suctions and two discharge openings_, so that either side may be connected up. The tool box and driver’s seat are in front of the engine. The frame rests upon springs, to make the machine easy running.

_The Fox Boiler_ with which the Metropolitan and other engines are equipped deserves an extended notice. It is shown in vertical section in Fig. 395, the arrows indicating the steam and water circulation. Its design, while simple, embodies some original ideas as to the arrangement of the tube surface method of circulation, etc.; it is a steam generator of _the water tube type_ designed to meet the requirements peculiar to the fire service. The steam take-off and sectional view of shell with the tube system removed is shown in Fig. 397.

NOTE.—Working pressure can be generated in this boiler in six minutes
from cold water, and the provisions for expansion are so near perfect
that no bad effect is noticeable from such severe treatment. The
manifold tube sections are tested to 600 pounds pressure, and are put
together with great care; _the manifolds are counter-bored_ to admit
the full diameter of the tube, leaving none of the threaded portion
exposed.

The boiler consists primarily of a simple annular shell heavily stay-bolted throughout, and constitutes a water-legged fire-box and steam reservoir; the principal heating surface of the boiler consists of straight water tubes, manifolded in sectional form and housed within the shell, the general scheme providing arrangements to make all connections readily accessible, and permitting the withdrawal from the boiler of any one or all of the several tube sections; the shell, being practically a permanent feature, need seldom be disturbed by reason of subsequent repairs or renewals of the tube systems.

It may be noted that the lower part, or water leg, of the shell is contracted for the purpose of facilitating the rapid generation of steam, and also providing the maximum grate area; at a point somewhat below the water line of the boiler, the inner shell is flanged inward, thereby enlarging the annular space between the inner and outer sheets for the purpose of providing a more copious reservoir.

The water line being carried in this larger part of the shell, tends to prevent the rapid fluctuation of the water level, and the increased area of its surface at this point is favorable to the disengagement of the steam.

FIG. 399.]

FIG. 400.]

When held at its normal point, the water line protects the flanged part of the inner shell; but no damage can occur, either from a willful or an accidental drawing down of the water, as the spray deflected through the nipples of the outer tubes is sufficient to protect the flange, although the actual water level is well down in the leg.

The steam in contact with the upper part of the shell is by no means dry, and the heat absorbed at this point is amply sufficient to protect it. To insure a delivery of dry steam to the cylinders, a peculiar _“take-off” ring_ is provided at the highest part of the steam reservoir, the same encircling the inside sheet of the shell. The upper edge of the ring is perforated at a distant point from the throttle, and the steam entering the ring chamber in small streams is held in close contact with the hot shell at a point closely adjacent to the upper line of rivets; the steam by this means is dried during its passage to the throttle, and the heat thus absorbed serves as a protection to the rivets just referred to.

NOTE.—The life of both water tubes and fire tubes is generally found
disproportionate to the heavier parts used in boiler construction,
and experience shows conclusively that the cost of subsequent
maintenance is measured directly by, and may be diminished by, the
facility with which these indispensable parts may be replaced or
repaired in an emergency.

The principal heating surface of the boiler is contained in the vertical water tube sections, which comprise and will be referred to, as _an inner and an outer tube system_.

_The outer system_, embraces the short manifold sections which completely encircle the fire-box walls. The top end of each section is screwed and suspended from the flanged part of the shell, and the lower end is stayed by direct connection with the leg of the fire-box. _The tubes are “staggered”_ in their manifolds, thereby exposing the greatest possible surface to the fire, and filling out the space due to the difference in the width of the water-leg and steam space of the shell.

The direct application of heat to the tubes causes a natural and active upward current therein, which in turn induces a corresponding downward movement of the water in the leg of the fire-box, and promotes the flow into the feed pipes.

_The inner-tube system_ comprises those tube sections which extend to the upper limits of the boiler, their number and arrangement being such as to completely fill the interior of the shell above the space required for the combustion of the fuel. The construction of the vertical inner-tube system is simple, and consists of the required number of manifold sections, suitably arranged to conform to the circular space occupied, the flat inner end of each upper manifold being rigidly bolted to a heavy transverse beam, which in turn is supported in suitable pockets secured to the upper part of the shell.

At the top of the boiler, each section has its own connection with the steam space, and it is easy to remove either one of the sections separately without disturbing the others; _or the entire inner-tube system can be raised out of the boiler as a whole, after breaking the proper connections_, all of which are accessible. The current of steam and water carried over through the top connections of the inner system is generally sufficient to keep the tubes clear of scale; and the point of discharge and disengagement is brought down low, to prevent its mixture with the drier steam contained in the highest part of the shell.

When connected to a stationary boiler, as is now the general practice in fire departments, the circulative currents of water reach all parts of the boiler, hence its contents may be kept uniformly at any desirable temperature.

_A stationary heater for the fire engine_ consists of a small boiler, placed at some convenient point near the same when in quarters. It is connected with the engine boiler by means of suitable circulating pipes, the entire arrangement being adapted to supply hot water through pipe connections which separate automatically as the engine leaves the house.

Although the best types of fire engine boilers require but a few minutes’ time to generate a working pressure from cold water, the general adoption of many improvements has made the stationary heater an essential part of a complete equipment.

Experience proves that the life of the boiler is prolonged by being kept constantly in a state of activity, and the elevated temperature of the water insures prompt and efficient work by the steamer at the very time when a few moments’ delay may breed disaster.

_The pumps_ fitted and adapted to steam fire engines comprise two separate and distinct double acting piston pumps united in a single body and akin in many details to the duplex pump.

Calling in mind the well-known fact, that, in drawing a water supply the only power available to bring the fluid under forcing influence of the pump’s pistons is the limited pressure of the atmosphere, therefore the importance of all details concerned in first inducing an entry of the water will be readily conceded. Easy and unrestricted “suction ways” in direct communication with properly proportioned receiving valves (and these valves suitably arranged in close proximity to the working barrels of the pump), are the conditions that must always remain paramount, and to which all other features must give way, to safely attain the desirable high piston speeds. The value of perfect, simple and direct water ways, the passages, and all which they imply, has been studied in the design of this pumping engine. See Figs. 403-407.

The facilities provided for exposing the interior mechanism permits all such parts to be quickly reached for examination, or detached for renewal or repair, and this can be done without dismounting the entire pumps or greatly disturbing their exterior attachments. It will be seen, by reference to the cuts, that all of the valves can be easily and quickly examined, and also replaced, by removing the caps that enclose the chambers; all joints required for this purpose are made between flat surfaces planed true, as shown in Fig. 404; gun metal, or other suitable composition, is used and no part of the pump body is subject to wear, either by friction or corrosion. _All valve seats are screwed into place_, and either these or the working barrels of the pump may be readily replaced with new ones, in case the same should become worn. All stud bolts, nuts, etc., coming in contact with water, are made of drawn phosphor or Tobin bronze; nipples, piping, etc., are of brass.

Suction or hydrant connection may be made at either side of the engine; and, in operation, the central core of the pump body is _practically a continuation of the suction hose_, and serves to establish a direct communication with the receiving pump valves, arranged on opposite sides of the chamber. This chamber, as shown in the sectional view, Fig. 408, thus _becomes the distributing center, from which the incoming water flows to the suction valves_. The current from the suction is not required to change its general direction, and but little friction is encountered by the water in its diversion through the pump valves.

The position of the suction or receiving valves, in relation to the water cylinders, may be understood by reference to Fig. 408, which shows the same arranged in a cluster around the open ends of the barrels. The suction valve area is large, and the proportions adopted contribute largely to the smooth running of the pump, under conditions of speed seldom attempted in ordinary practice.

The valves in this pump are controlled by improved springs, the tension of which is at all times the same; and which are made of phosphor bronze; _the force chambers_ in opposite ends of the pumps are practically equal, and, owing to the close proximity of the valves, the clearance is reduced to a minimum The discharging outlets are elevated above the highest point of the valve chambers, and the communicating passages are designed to prevent conflicting currents, and also to permit the pump to free itself promptly of air. The pistons are of a frictionless type, and in accordance with the usual practice of working double pumps in unison, the cranks controlling the movements of the pistons are placed at 90 degrees.

A convenient and effective arrangement of suction strainers is shown in Fig. 409. Perforated cages are introduced into the suction chambers through the inlets on opposite sides of the pump. The ends of these cages are open, and a short sleeve, which is permanently secured within the pump, serves to support and also to establish communication from one cage to the other.

The surface of both cages is, therefore, available as a strainer, and any obstruction entering with the water is carried to the opposite side, to a point where it can be removed, without first detaching the suction hose.

The driving mechanism supplied with the American Pump is shown by Figs. 389 and 394, which are perspective views engraved from photographs. It may be noted that the design is practically compact and well balanced, and embodies many excellent advantages found in no other type of fire engine.

_The pumps, steam cylinders and driving parts_ are built as a unit, and have no direct connection with the boiler other than the necessary stays and pipe connections, all of which are readily accessible and visible for inspection at any time.

The steam cylinders used in connection with the pumps are of the ordinary slide valve type. The valve chests are easily opened from either side of the engine for examination, and the valve rods are made from a special composition and can not corrode. The valve motion is simple, and there is nothing connected with the steam ends that may not be quickly understood.

MAXIMUM DIMENSIONS OF STEAM FIRE ENGINES.

_Appurtenances._ In addition to such special fixtures as may be necessary for their proper working, the following articles are a part of each engine:

Smooth bore rubber suction hose, carried in substantial brackets on
the machine and fitted with suitable couplings, hydrant connections
and interchangeable outside suction strainer.

Polished copper vacuum and air chambers.

Fuel pan of ample capacity.

Detachable footboard, for the engineer and an assistant.

Driver’s seat, for either one or two men.

Seat cushion.

Whip socket.

Blanket holders, when desired.

Foot brake, to operate from front or rear.

Horse pole, with whiffletrees.

Trace and pole chains or straps with patent snaps.

Gong attached to driver’s footboard or

Locomotive bell mounted over steam cylinders.

Steam signal whistle.

Grate bars, dumping or stationary pattern.

Stationary sprinkler, for wetting ashes under grate.

Pop safety valves.

Variable regulator for exhaust nozzles.

Auxiliary steam blast into chimney.

Nickel-plated brass chimney dome and bands around boiler.

Two steam pressure gauges.

Water pressure gauge.

Glass water gauge on boiler with extra tube.

Try cocks on boiler.

Brass feed pump for boiler.

Auxiliary feed to boiler from main pumps.

Churn valve, for feeding boiler when streams are shut off.

Necessary air, drain and pet cocks.

Surface blower from water line of boiler.

Blow-off cocks and cleaning plugs in fire-box leg.

Cleaning and “thaw” hose with connections.

Regrinding throttle valve, with drain cock attached.

Automatic or sight-feed lubricators.

Cylinder oil cups.

Necessary oil cups and lubricating devices.

Hand oil cans.

Three-pint reservoir cans for cylinder and lubricating oil.

Keepers, attached to all stuffing-box nuts.

Poker, shovel and other stoking tools.

Fire department hand lanterns, carried in brackets.

Adjustable screw wrenches.

Universal spanner for slotted nuts.

Hose spanner.

Hammer.

Tool box, with all necessary monkey-wrenches, cold chisels, and files.

Two polished play pipes and nozzles.

Stop valves next to boiler and flow and return pipes for use with
stationary Fire Engine Heaters.

THE SILSBY ROTARY STEAM FIRE ENGINE.

The distinguishing feature of this engine will be found in the fact that, in both the cylinder and pump, the rotary type is substituted for the reciprocating or piston principle.

The larger sizes of these engines, Fig. 411, are hung on platform truck springs in front and on half-elliptic springs in the rear, and are braced and stayed to withstand violent shocks in the rapid driving over pavements. Although fitted to be drawn by horses only, they can be supplied with rope reel and drag rope.

_The Silsby steam cylinder_ consists of two rotary pistons or cams, mounted on steel shafts and working together within an elliptical steam-tight case. Live steam from the boiler enters at the bottom of this case, and in its passage presses apart their long teeth or abutments, causes the two cams to rotate, and exhausts from the top into the tank and feed-water heater; these cams are provided with teeth or cogs, adapted to mesh with corresponding recesses in each other, so that a steam tight joint is maintained between them and leakage thereby prevented from passing directly upward into the exhaust.

The sides of these cams have their arcs turned to fit the heads of the case, and are so adjusted that, while being practically steam tight, allowance is made for expansion and contraction. In the ends of the longest teeth of the revolving cams are placed removable packing strips, which are forced outward into contact with the cylinder walls by means of springs. These packing strips may be removed through openings in the sides of the cylinder, and readjusted to take up the wear, which is confined to the ends of these adjustable strips. This can be done without taking the pump or cylinder apart.

_The construction of the pump is similar to that of the cylinder_; in this there are three long teeth in each cam instead of two. One shaft of the pump is coupled to the corresponding shaft of the cylinder, there being outside gears on both cylinder and pump to compel a uniform motion of the cams and to equalize the pressure. This construction secures a transmission of power at once direct and positive in Fig. 412.

The stuffing-boxes, used on both cylinder and pump, are self-adjusting, reduce friction and insure tightness. Valves are entirely absent from the pump and cylinder. The water ways being large, anything liable to enter the suction will pass through the pump without injury or interruption; the pump requires no priming, but when started will immediately without the aid of a check valve lift water vertically any required distance up to 29 feet.

_The construction of the boiler_ ordinarily supplied with this engine is shown in Figs. 414-415. In the fire-box hangs a series of circulating water tubes arranged in concentric circles and securely screwed into the crown sheet. These drop tubes are closed at their lower ends by means of wrought-iron plugs welded in, and within each of them is placed a much smaller and thinner tube, which latter is open at both ends. The cooler water in the boiler descends through the inner tube and is thus brought directly into the hottest part of the furnace, whence, after being for the most part converted into steam, it ascends through the annular spaces between these inner and outer tubes.

_The gases of combustion_ pass from the fire box to the stack through smoke flues, the lower ends of which are expanded into the crown sheet, and the upper ends into the top head of the boiler.

TABLE OF EFFECTIVE FIRE STREAMS.

_USING 100 FEET OF 2-1/2-INCH ORDINARY BEST QUALITY RUBBER-LINED HOSE BETWEEN NOZZLE AND HYDRANT, OR PUMP._

================================+=======================
Smooth Nozzle, Size | 3/4-inch.
--------------------------------+---+---+---+---+---+---
Pressure at Hydrant, lbs. | 32| 43| 54| 65| 75| 86
Pressure at Nozzle, lbs. | 30| 40| 50| 60| 70| 80
Pressure Lost in 100 feet, | | | | | |
2-1/2-inch Hose, lbs. | 2| 3| 4| 5| 5| 6
Vertical Height, feet | 48| 60| 67| 72| 76| 79
Horizontal Distance, feet | 37| 44| 50| 54| 58| 62
Gallons Discharged per Minute | 90|104|116|127|137|147
================================+=======================
Smooth Nozzle, Size | 7/8-inch.
--------------------------------+---+---+---+---+---+---
Pressure at Hydrant, lbs. | 34| 46| 57| 69| 80| 91
Pressure at Nozzle, lbs. | 30| 40| 50| 60| 70| 80
Pressure Lost in 100 feet, | | | | | |
2-1/2-inch Hose, lbs. | 4| 6 | 7| 9| 10| 11
Vertical Height, feet | 49| 62| 71| 77| 81| 85
Horizontal Distance, feet | 42| 49| 55| 61| 66| 70
Gallons Discharged per Minute |123|142|159|174|188|201
================================+=======================
Smooth Nozzle, Size | 1-inch.
--------------------------------+---+---+---+---+---+---
Pressure at Hydrant, lbs. | 37| 50| 62| 75| 87|100
Pressure at Nozzle, lbs. | 30| 40| 50| 60| 70| 80
Pressure Lost in 100 feet, | | | | | |
2-1/2-inch Hose, lbs. | 7| 10| 12| 15| 17| 20
Vertical Height, feet | 51| 64| 73| 79| 85| 89
Horizontal Distance, feet | 47| 55| 61| 67| 72| 76
Gallons Discharged per Minute |161|186|208|228|246|263
================================+===+===+===============
Smooth Nozzle, Size | 1-1/8-inch.
--------------------------------+---+---+---+---+---+---
Pressure at Hydrant, lbs. | 42| 56| 70| 84| 98|112
Pressure at Nozzle, lbs. | 30| 40| 50| 60| 70| 80
Pressure Lost in 100 feet, | | | | | |
2-1/2-inch Hose, lbs. | 12| 16| 20| 24| 18| 32
Vertical Height of Stream, feet | 52| 65| 75| 83| 88| 92
Horizontal Dist. of Stream, feet| 50| 59| 66| 72| 77| 81
Gallons Discharged per Minute |206|238|266|291|314|336
================================+=======================
Smooth Nozzle, Size | 1-1/4-inch.
--------------------------------+---+---+---+---+---+---
Pressure at Hydrant, lbs. | 49| 65| 81| 97|113|129
Pressure at Nozzle, lbs. | 30| 40| 50| 60| 70| 80
Pressure Lost in 100 feet, | | | | | |
2-1/2-inch Hose, lbs. | 9| 25| 31| 37| 43| 49
Vertical Height of Stream, feet | 53| 67| 77| 85| 91| 95
Horizontal Dist. of Stream, feet| 54| 63| 70| 76| 81| 85
Gallons Discharged per Minute |256|296|331|363|392|419
================================+=======================
Smooth Nozzle, Size | 1-3/8-inch.
--------------------------------+---+---+---+---+---+---
Pressure at Hydrant, lbs. | 58| 77| 96|116|135|154
Pressure at Nozzle, lbs. | 30| 40| 50| 60| 70| 80
Pressure Lost in 100 feet, | | | | | |
2-1/2-inch Hose, lbs. | 28| 37| 46| 56| 65| 74
Vertical Height of Stream, feet | 55| 69| 79| 87| 92| 97
Horizontal Dist. of Stream, feet| 56| 66| 73| 79| 84| 88
Gallons Discharged per Minute |315|363|406|445|480|514
--------------------------------+---+---+---+---+---+---

N.B.—Mr. JOHN R. FREEMAN, member of the New England Waterworks
Association, should have the credit of this carefully arranged
table.—See also page 125 for data relating to Nozzles.

_The Clapp & Jones piston engine_ in design has features peculiar to itself; Fig. 416 represents one of six sizes, adapted particularly to city service.

The illustrations, Figs. 417 and 418, _show the vertical pump_ as built for the larger engines: namely, the sizes known as Extra First, First, Second, Third and Fourth. The complete engine corresponding to the detailed views is shown by Fig. 416 on the preceding page.

The principal details are very clear in this engraving. The steam and water ends, together with the crank and reciprocating mechanism, are compactly arranged and the complete structure which comprises these parts is rigidly self-contained. The steam cylinders and valve chest are cast in a single piece and while this part is firmly secured to the boiler, all steam and exhaust connections are entirely independent of these fastenings.

_The Clapp boiler_ is represented in Fig. 419. Reference to the annexed illustration makes clear the special features of this boiler, which consist chiefly of a series of spiral water-tube coils arranged within the fire-box. The coils are of copper and are produced by the seamless drawn process. Each coil is connected separately to the boiler, and the spiral form of these tubes permits freedom for expansion and contraction without strain on the terminal joints. The connections and the ends of the tubes are made by means of threaded nipples, jam nuts and corrugated copper washers, and the joints thus made insure tightness, yet admit of ready disconnection at any time.

The lower ends of the coil tubes are directly joined to the hollow fire-box walls and the upper terminals are arranged to discharge the circulated water over the crown sheet. This upward movement of the water within the spiral coils is caused by the application of heat to the outer surfaces of the tubes, and the circulation thus set up induces _a corresponding downward action in the leg of the boiler_. The circulation, therefore, continues without interruption so long as fire is maintained on the grate. In operating this boiler the water should be carried a few inches above the level of the crown sheet, but owing to the protection afforded by the constant distribution of water over the crown sheet, the limit of safety is not reached until the water is nearly out of the fire-box leg.

An improvement in the design of this boiler is _the water-circulating deflector_, which was devised to occupy the central space within the coil tubes. This deflector comprises an additional sectional unit, and its action coincides with the functions served by the coil tubes. The prime object of this device is to break up and direct the gases of combustion in a manner that adds to the heat-absorbing qualities of the coil tubes. See Figs. 420, 421.

Extending from the crown sheet to the top head are the smoke flues, which are securely expanded at both ends, and through which the gases of combustion pass from the fire box to the stack.

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Pumps and Hydraulics, Part 2 (of 2)Chapter III: Part 3

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