Chapter VI: Part 6

The current is thus suddenly stopped; this causes a reaction, which produces pressure sufficient to open another valve (inlet valve) between the current-pipe and an air chamber, and a portion of water enters by means of the force of the current, but by so doing the current has spent its force; the outlet valve at the end of the chamber falls by its own weight, and the pressure in the pipe ceasing, the inlet valve in the air-chamber falls and closes the opening. The condition of things is then restored; the water then acquires a momentum which closes the outlet valve and forces more water again into the chamber. A very slight descending column is capable of raising one ascending very high. In all cases the drive-pipe or inlet pipe must be sufficiently long to prevent water being forced back into the reservoir. The air-chamber serves to keep up a steady supply from the reservoir, preventing spasmodic action. To prevent admixture of air with the water in the air chamber, which is caused by pressure of water when raised to a great height, a small hole should be made on the upper side of the inlet pipe, immediately in front of the same. By the action of the ram at each stroke, a partial vacuum is formed below the air chamber, and the air rushing through the small hole in the inlet pipe, passes into the air chamber, making good that which the water absorbs.

NOTE.—In 1797 Matthew Boulton (manufacturer and practical engineer,
and in later life a partner of Jas. Watt, the Father of the steam
engine) obtained a patent for a mode of raising water by impulse. The
apparatus had excited much attention in France, under the name of
_Montgolfier’s hydraulic ram_, and Boulton added to it a number of
ingenious modifications, which were the basis of his patent.

Fig. 150 shows in section the construction of the ram in its simplest form in which E is the reservoir, A the pipe in which the water falls, B the channel, _a_ and _b_ the valves, C the air-chamber, and D the discharge. Water first flows out in quantity through the valve _a_, and as soon as it has acquired a certain velocity it raises that valve, closing the aperture. The impact thus produced, acting on the sides of the pipe and the valve _b_, raises this valve, and a quantity of water passes into the air-chamber shutting off air and compressing it in the space above the mouth _d_ of the discharge D. This air by its electric force closes the valve _b_, and the water which has entered is raised in the discharge D.

As soon as the impulsive action is over, and the water in the channel A comes to rest, the valve _a_ again falls by its own weight, the flow begins afresh, and when it has acquired sufficient velocity the valve _b_ again closes, and the whole process is repeated.

_The efficiency of hydraulic rams_ has been much discussed; exhaustive practical tests have been made and the results have been reduced to formulas. Whittaker’s Mechanical Engineer’s Pocket Book gives the following:

G × H
E = -----
g × h

where E = the efficiency;
G = gallons of drive water used;
g = gallons of water raised;
H = height of fall, in feet;
h = height to which the water is raised, in feet.

_The Table_ given on page 174 is from the _American Engineer_. Its use is apparent, thus: when the height of fall in feet is, say 12 feet, and the elevation of discharge above the delivery valve of ram, in feet, is 30 feet, _the efficiency_ or per cent., is ·3282. (_Example_) of 100 gallons 32-82/100 gallons would be delivered.

_The double hydraulic ram_ is shown in Fig. 151. A sectional view of the same device is shown in Fig. 152, the cuts represent the Rife hydraulic engine, or ram,—a so-called double acting or double supply type of the water ram. It is more clearly described by considering it, first, as a single machine by disregarding its double supply feature.

First, suppose the opening at _H_, Fig. 152, to be closed, the valve _B_ being open, the water from the source of supply from more or less elevation above the machine flows down the drive pipe, _A_, and escapes through the opening at _B_ until the pressure due to the increasing velocity of the water is sufficient to close the valve, B. When the flow through this valve ceases, the inertia of the moving column of water produces a reaction, called the ramming stroke, which opens the valve at _C_, and compresses the air in the air chamber, _D_, until the pressure of the air plus the pressure due to the head of the water in the main, is sufficient to overcome the inertia of the moving column of water in the drive pipe. This motion may be likened to the oscillation of water in a ^U^ shaped tube. The instant the column of water in the drive pipe comes to rest, and the air pressure being greater than the static head alone, the motion of the moving column is reversed, and the valve, _C_, closes. The water in the drive pipe then moves backward, and with the closing of valve _C_ a partial vacuum is formed at the base of the drive pipe. This negative pressure causes the valve, _B_, to open again, and completes the cycle of operations. At the moment negative pressure appears the little snifting valve, _E_, admits a small quantity of air, and at the following stroke this air rises into the air chamber _D_, which would otherwise gradually fill with water, or the air is gradually absorbed by the water.

In this machine the valve, _B_, is made as light as is consistent with the necessary strength, and the negative pressure at the completion of the stroke opens the valve. In the largest size of these machines this valve is 18 inches in diameter, with a head of 8 feet, which is a common head for use with hydraulic rams; the static pressure on the under side of this valve is 883 pounds; it is seen that so great a shock in a valve of this weight would rapidly destroy both valve and seat.

The waste in a mechanism of the Rife engine consists of a large port with ample opening and a large rubber valve or overflow with a balance counterweight and spring seat, which removes almost entirely the jar of closing. The valve, _C_, in the air chamber consists of a rubber disc with gridiron ports and convex seats fastened at the center and lips around its circumference. The object of this arrangement is to transfer the shock from the power of the driving water to the air cushion with the smallest possible friction and vibration.

After the valve, _C_, closes, the pressure in the air chamber forces the water in the air chamber out into the delivery pipes. The Rife engine is claimed to elevate water 30 feet for each foot of fall in the driving head; the machine is built in sizes to elevate as much as 150,000 gallons per day, the efficiency being about 82 per cent.

When a water supply pipe is attached to _H_, the engine is called _double acting_; spring water, or that which is purer than the water used to drive the engine, may then be supplied through the supplemental drive pipe _I_, and by a proper adjustment of the relative flow of the impure driving water, and that of the pure supply, the engine may be made to deliver only the pure water into the mains. This method is employed where the supply of pure water is limited.

The most important detail in which the Rife engine differs from the ordinary hydraulic ram is _the waste valve_. It will be seen in the engraving that the counterweight on the projecting arm of this valve permits the adjustment of this valve to suit varying heads and lengths of drive pipe. By adjusting the counterweight so that the valve is nearly balanced, the valve comes to its seat very quickly after the flow past it begins. The result is that the ram makes a great number of short, quick strokes, which are much easier on the valves and seats than slower and heavier strokes. The stroke must be sufficiently powerful to act efficiently in overcoming the head in the delivery pipe. The adjustable weight permits this to be effected with great nicety.

NOTE.—The engine illustrated weighs approximately 2,800 pounds; the
capacity of the air chamber is 20-3/4 cubic feet; diameter of drive
pipe, 8 inches; diameter of the waste valve, 18 inches; weight of
waste valve, 50 pounds; diameter of delivery pipe, 4 inches; height
to top of air chamber, 7-1/2 feet.

_Lifts and Cranes._ These, as hydraulic machines, are adapted to very many places where other power apparatus is too slow; they operate on the same principle as the hydraulic press; having a cylinder and a ram: they have chain wheels attached to the outer end of the ram, as shown in the illustration.

As the ram advances the chain is shortened and when it recedes the chain is lengthened, thus, the weight attached to the end of the chain is raised and lowered. The hydraulic “lift” in passenger elevators operates upon the same principle and this gives an idea of the rapid motion capable of being imparted to the load. It is by the adaptation of hydraulic lifts and cranes in steel mills that such economical results have been attained.

PUMPS AS HYDRAULIC APPARATUS.

In Figs. 153 and 154 are shown representations of certain apparatus, long used in schools, to explain the rather obscure operation, of even the simplest of pumps; these models are made of glass so that all the movements of the valves, etc., may be clearly noted. Credit is due to Monsieur Ganot, author of Elements of Physics, for the following.

_Fig. 153 represents a model of a suction-pump_ such as is used in lectures, but which has essentially the same arrangement as the pumps in common use. It consists, 1st, of a _glass cylinder_, B, at the bottom of which is a valve, S, opening upwards; 2nd, of a _suction-tube_, A, which dips into the reservoir from which water is to be raised; 3rd, of a _piston_, which is moved up and down by a rod worked by a handle, P. The piston has a hole in its center; this upper aperture is closed by a valve, O opening upwards.

When the piston rises from the bottom of the cylinder B, a vacuum is produced below, and the valve O is kept closed by the atmospheric pressure, while the air in the pipe A, in consequence of its elasticity, raises the valve S, and part of it passes into the cylinder. The air being thus rarefied, water rises in the pipe until the pressure of the liquid column, together with the pressure of the rarefied air which remains in the tube, counterbalances the pressure of the atmosphere on the water in the reservoir.

When the piston descends, the valve S closes by its own weight, and prevents the return of the air from the cylinder into the tube A. The air compressed by the piston opens the valve O, and escapes into the atmosphere by the pipe C. With a second stroke, the same series of phenomena is produced, until after a few strokes the water reaches the cylinder. The effect is now somewhat modified; during the descent of the piston the valve S closes, and the water raises the valve O, and passes above the piston by which it is lifted into the upper reservoir D. There is now no more air in the pump, and the water forced by the atmospheric pressure rises with the piston, provided that when it is at the summit of its course it is not more than 34 feet above the level of the water into which the tube A dips.

_In practice the height of the tube A does not exceed 26 to 28 feet_; for although the atmospheric pressure can support a higher column, the vacuum produced in the barrel is not perfect, owing to the fact that the piston does not fit exactly on the bottom of the barrel. But when the water has passed the piston, it is the ascending force of the latter which raises it, and the height to which it can be brought depends on the power which works the piston.

The action of this pump, a model of which is represented in Fig. 154, _depends both on exhaustion and on pressure_. At the base of the barrel, where it is connected with the tube A, there is a valve, S, which opens upwards. Another valve, O, opening in the same direction, closes the aperture of a conduit, which discharges from a hole, _o_, near the valve S, into a vessel, M, which is called the _air-chamber_. From this chamber there is another tube, D, up which the water is forced.

At each ascent of the piston B, which is solid, the water rises through the tube A into the barrel. When the piston sinks the valve S closes, the water is forced through the valve O into the reservoir M, and thence into the tube D. The height to which it can be elevated in this tube depends solely on the motive power which works the pump.

If the tube D were a prolongation of the tube J_ao_, the flow would be intermittent; it would take place when the piston descended, and would cease as soon as it ascended. But between these motions there is an interval, which, by means of the air in the reservoir M, ensures a continuous flow. The water forced into the reservoir M separates into two parts, one of which, rising in D, presses on the water in the reservoir by its weight; while the other, by virtue of this pressure, rises in the reservoir above the lower orifice of the tube D, compressing the air above. Consequently, when the piston ascends, it no longer forces the water into M, the air of the reservoir, by the pressure it has received, reacts on the liquid, and raises it in the tube D, until the piston again descends, so that the jet is continuous.

_Hydraulic Machine Tools._ Probably in no department of engineering has the use of hydraulic power met with more success than in its application to certain machine tools. This success is owing to the peculiar suitability of pressure—water as the motive agent for the performance of a certain class of operations requiring the exertion of a great force with comparative slow motion, as in punching, riveting, forging and the like.

The wide spread and successful use of hydraulic machines—of which a few only have been described and illustrated upon the pages of this book—is due to the necessity for such tools and the inventive ability of our tool designers.

_A large fixed hydraulic riveter_ is shown in Fig. below; it is capable of exerting on the rivet a pressure of 40 tons or more; the machine has a _working pressure_ of 1,500 pounds per square inch. Working pressures of 5,000 to 10,000 pounds per square inch are used in _hydraulic forging presses_, but in the riveter much less pressure is required.

NOTE.—_The proportions_ of this machine are immense. The platform
weighs 22,500 lbs. and is operated by a single lever shown in the
side view. The “_gap_” is 8 feet across. The machine has a large
steel “_stake_” carrying the stationary die; this is held in tension
strain by the two steel bolts shown, one upon each side of the
machine. The other part of the jaw is cast iron.

CLASSIFICATION
OF PUMPS

CLASSIFICATION OF PUMPS AND PUMPING ENGINES.

The simplest division of the subject matter relating to this branch of practical mechanics is that which goes back to the very earliest of times; it is thus:

1. Hand Pumps.
2. Power Pumps.

The names indicate the dividing line between the two. The following are more modern divisions, indicating the method of action distinguishing each:

1. Suction or Lift Pumps.
2. Force Pumps.
3. Suction and Force Pumps.

These again may be reciprocating or rotary. The powers actuating pumps are, in the main, as follows:

1. Manual.
2. Animal.
3. Belts.
4. Water.
5. Wind.
6. Steam.
7. Gas.
8. Electricity.

These various motors give distinct names to general classes, thus, electric pumps, belt pumps, elevator pumps, etc. A sub-division of titles indicating differences in construction are these:

1. Vertical Pumps.
2. Horizontal Pumps, or again
1. Single Acting Pumps.
2. Double Acting Pumps.

The list is still further extended, as pumps vary in design to suit their several uses, and are defined as rope, chain, diaphragm, jet, centrifugal, rotary, oscillating, cylinder. It is with the last named with which this volume has principally to deal; cylinder pumps cause the last given classification, as they are either single or double acting.

A single acting pump does its work through one end of the cylinder or barrel of the pump.

In double acting pumps the motion of the piston in one direction causes an inflow of water, and a discharge at the same time, in the other; and on the return stroke this action is renewed as the discharge end alternately becomes the suction end; the pump is thus double acting.

Finally pumps may be classified with reference to particular uses to which they are specifically adapted by their form and the materials they are required to handle.

Pumps now raise, convey and deliver beer, molasses, acids, oils, and melted asphalt. They also handle such gases as air, ammonia, lighting gas and even oxygen.

In the orderly progress of the contents of the volume, it will be seen that the main subject, occupying many pages with illustrations, is that relating to “Steam pumps;” those having a _steam-end_ and a _water-end_ and which consist of pump and steam-motor combined. An interesting class under Vacuum-pumps will be found, 1, the combined vacuum and feed; 2, the combined vacuum and circulating and, 3, the combined vacuum and refrigerating pumps.

Under Pumping Engines and the Steam Fire Engine will be found a description of the most brilliant and fascinating of modern scientific and mechanical achievements; these two sections relate to hydraulic engineering in its highest development.

HAND PUMPS.

The _theoretical action of_ a pump has already been described and illustrated;—the _practical operation_ is described in the note below. The subject is important enough to justify the space it takes to present these two descriptions of the action of a pump.

The parts of which a pump is composed are: 1, _the barrel or cylinder_; 2, _the plunger or piston_; 3, _the valves_; 4, _the pipes_.

The barrel of a modern pump is a tube of metal having a water tight plunger or piston which moves freely up and down at the pleasure of the operator. This plunger is in its simplest form made of cast iron in two parts. The upper part consists of an arched part having a hole in its center to receive a bolt which passes through it and a jaw on the lower end of the pitman or connecting rod. The upper end of this pitman is attached to the pump handle by means of a bolt. The inside of the upper part of the plunger is threaded to receive the lower part with a cup leather packing and contains a valve of metal having a conical seat. Fig. 156 shows a design of a pump in common use in the 14th century.

NOTE.—The action of a pump is as follows: The piston or plunger by
moving to one end, or out of the pump cylinder, leaves the space it
occupied, or passed through, to be filled by something. As there is
little or no air therein a partial vacuum is formed unless the supply
to the pump is of sufficient force to follow the piston or plunger
of its own accord. If this is not the case, however, as it is when
the water level from which the pump obtains its supply is below the
pump itself, there being a partial vacuum produced, the atmospheric
pressure forces the water into the space displaced by the plunger or
piston, continuing its flow until the end of stroke is reached.

The water then ceases to flow in, and the suction valve of the pump
closes, forbidding the water flowing back the route it came. The
piston or plunger then begins to return into the space it has just
vacated, and which has become filled with water, and immediately
meets with a resistance which would be insurmountable were the water
not allowed to go somewhere. (See next page.)

Its only egress is by raising the discharge valve by its own pressure, and passing out through it. This discharge valve is in a pipe leading to the boiler, and in going out of the cylinder by that route the water must overcome boiler pressure and its own friction along the passages. Water is inert and cannot act of itself; so it must derive this power to flow into the feed pipe and boiler from the steam acting upon the steam piston of the pump. The steam piston and pump piston are at the two ends of the same rod. Therefore the steam pressure exerted upon the steam piston will be exerted upon the pump piston direct.

Between the upper and lower parts of the plunger a cup leather is introduced before these parts are screwed together. This cup leather, while it allows the plunger to move freely, also makes a water-tight joint.

The lower valve consists of a piece of cast-iron flat on the bottom and circular in shape about three-eighths inch thick with a curved toe at one side. This iron disc is secured to the flat leather valve by a screw that passes through the valve and is threaded in the disc.

The object of this toe upon the disc is to open the lower valve by means of raising the pump handle as far as it will go which lowers the plunger upon the toe and tips the lower valve upon its seat. This same operation also lifts the valve in the plunger off its seat, so that all the water in the barrel drains back into the well so the pump is kept from freezing up in winter.

The leather which forms the lower valve is held in place by clamping the pump barrel upon it, so that it is held between the barrel and the base plate.

Hand pumps are primarily divided into: 1, suction or lift pumps; 2, force pumps, and 3, suction and forcing pumps; 4, also pumps for exhausting air from vessels.

Of the first class, the common single-acting house-pumps shown in Figs. 157 and 158 are examples; the pumps are simply modifications of the suction-pump; a common form of lift-pump has a pitman-rod which pushes the water up instead of lifting it through a spout at or near the top of the cylinder.

The details of the suction-pump are as follows—at the bottom of the cylinder is a pipe communicating with the liquid to be raised, and a valve which opens from beneath. A similar valve is placed in the piston.

A force-pump is shown in Fig. 159; from the two figures the difference between the lift and the force-pump may be understood; while the former raises the liquid above its piston from which it flows under no pressure, the latter forces it out of the barrel under a varying pressure which depends upon circumstances. When the piston rises the suction valve opens, and the valve in the piston closes by the air-pressure. The liquid then enters the barrel beneath the piston. On the descending stroke the suction valve closes, and the liquid flows upward into the discharge pipe.

_In Fig. 160 is shown an air-chamber_ attached to a force-pump for the purpose of preventing shocks in the discharge, and for producing a steady flow; air-chambers are also frequently attached to suction pipes for a similar purpose.

According to the underlying principles of action thus far explained hundreds of thousands of pumps have been constructed and operated. It is beyond the limits of this volume—or any single book to give the names and details of these so-called “hand-pumps,” however, three approved styles are shown in Figs. 161, 162, 163.

Fig. 161 represents a _double acting force pump_ used extensively on ship-board, wharves, around factories, mills, etc., and in residences, for tank pumping. On ships these pumps perform the three-fold purpose of filling boilers when cold, washing down decks and to satisfy government inspection as to fire protection; in service in mines they are unaffected by mine water, the working parts being made non-corrosive. It is claimed that a three-inch diameter cylinder with a stroke of four and a half inches with a 1-1/4-inch suction pipe and 1-inch discharge pipe will lift and force water 150 ft. high and has a capacity of ·28 gallons for each stroke, with the water not more than twenty-five feet below the pump.

Fig. 162 represents _a two cylinder force pump_; this has vertical single acting pistons actuated by one lever, producing the same results as a double-acting pump. It is claimed that the total lift and force, from supply to point of delivery, with the pump not more than twenty-five feet above water will attain one hundred feet; that a 3-inch × 4 inch cylinder, 1-1/2-inch suction and 1-1/4-inch discharge will deliver ·24 gallons of water for each stroke.

Fig. 163 represents a widely used type of suction pump, it is designed for vessels of not more than fifteen to twenty feet deep; for contractors who wish to pump large quantities of water from excavations, etc.; for irrigation or any other purpose where a compact and capacious pump is desired.

The lever may be worked from three different points as shown by lugs on the illustration. The lever socket is made at such an angle that the bent wrought iron lever when put in one side up, is right for ordinary pumping and by simply changing it the other side up, it becomes a vertical lever. The valves are accessible and removable by hand from above. It is claimed that with 8-1/2-in. diameter cylinder and 6-in. stroke that the capacity is 1-47/100 gallons for each stroke, with 20 feet lift—the suction pipe being 3-in. in diameter.

In the illustrations (Figs. 161 and 162) it will be noticed that the discharge is conveniently arranged to receive either fire hose, or iron pipe connections for other uses, as in mines and on ship-board.

_Being made in large factories_, there are immense numbers in world-wide use; every detail of these pumps is carefully considered; the sizes manufactured range from 2 inches to 6 inches diameter of cylinders, with strokes 4, 4-1/2 and 5 inches.

_The capacity_ of each pump is also given in the published lists by the makers; this is given under the heading “Capacity per Revolution” with the added information as to the best sizes to be used for the suction and discharge pipes.

NOTE.—It were well for the student to know that in case of breakage
or worn out parts of an otherwise serviceable apparatus that the
makers _have provided for their repairs_ as will be indicated by the
following taken from the catalogue of a well known manufacturer. “In
the following lists will be found descriptions of pieces for all
the staple pumps, which will prove of decided convenience. In this
connection we desire to impress most emphatically on the minds of
dealers that the threads are cut to exact and accurate gauges; all
holes in flanges, etc., drilled to templets; all castings made from
exact metal patterns, similar parts being always the same. Therefore,
repairs will invariably take the place of the broken parts.”

_Fig. 163 represents a Pitcher Spout Pump_, of large size for contractors, and Fig. 164 the parts of a common house pump. The two figures show pumps substantially the same.

The smallest size “listed” of this pump has a cylinder diameter of 2-1/2 inches, fitted with 1-1/4 in. pipe and it has a capacity of ·09 gal. per stroke and it takes more than eleven strokes to pump a single gallon. With a cylinder 4-1/2 inches, with pipe 1-1/2 in. diam., the pump has a capacity of ·34 gal. per stroke.

The engraving 164 shows a pitcher pump dissected, in which A represents the lever or handle, B the plunger which contains the discharge valve and is made tight by a cup leather packing, C is the fulcrum for the lever, D the barrel or cylinder, E the lower or suction valve, F the base which supports the pump. The leather which forms the valve E also makes the joint between the cylinder and the base.

Fig. 165 represents a _Two-Cylinder Suction and Force Pump_ arranged with extension levers. When these levers are put in place, they afford room for a large force of men to work, renders this pump a most powerful engine for throwing water on fires, or supplying it for many uses about factories, warehouses, wharves, etc.

The discharge hose can be fitted both ends for wrought-iron pipe or either end for hose. The Table below gives the makers’ numbers, the diameter of the cylinders, etc., and also distance to which the water can be lifted or forced.

TABLE OF SIZES, CAPACITIES, ETC.

---+--------+---------+---------+------ -------+--------------+---------
No.|Diameter| Stroke |Capacity | Discharge | Suction |*Lift and
|Cylinder| | per Rev.| | | Force
---+--------+---------+---------+--------------+--------------+---------
4 |3 in.|6-1/2 in.| ·40 gal.|1-1/4 in. hose|1-1/2 in. pipe|100 ft.
4 |3 „ |6-1/2 „ | ·40 gal.|1-1/4 „ |1-1/2 „ |100 ft.
6 |3-1/2 „ |6-1/2 „ | ·54 „ |1-1/2 „ |2 „ | 75 „
8 |4 „ |8 „ | ·87 „ |2 „ |2-1/2 „ | 75 „
10 |4-1/2 „ |8 „ |1·10 „ |2 „ |2-1/2 „ | 75 „
12 |5 „ |8 „ |1·36 „ |2 „ |2-1/2 „ | 75 „
16 |6 „ |7 „ |1·96 „ |2-1/2 „ |4 „ | 50 „
---+--------+---------+---------+--------------+--------------+---------

* _Total lift and force from supply to point of delivery, Pump not more than 25 feet above water._

Fig. 166 represents _a hand, rotary force pump_ provided with a balance wheel. A sectional view of this pump is given in Fig. 167; these pumps are adapted for almost any place or purpose where lift or force pumps can be used, they can be moved to any place where water is within suction distance and immediately operated.

The provision of a foot valve at the end of the suction pipe will keep it always filled.

_In the rotary pump there are no pistons._ As will be seen in the Fig. 167, there are two pinions of extremely coarse pitch meshing into one another with neat fit in the case; the joints become practically air-tight by the water which surrounds them and passes through the case.

Both pinions are supported by a journal at each end, the shaft of one being extended to receive a pulley or hand wheel as shown in Fig. 166, hence, one pinion causes the other to revolve. The teeth on the bottom side of the pinions move away from each other and form a partial vacuum which the water fills and is carried around between the teeth of the pinions on opposite sides and is discharged through a central opening in the case at the top, thence through the discharge pipe into the tank or reservoir.

In the small sizes of the rotary pump there is no trouble from leakage, until the parts become much worn.

_Bag Pump._ This is a form of bellows-pump in which the valve disc A, which takes the place of the bucket, is connected with the base of the barrel by an elastic bag distended at intervals by rings. This bag may be made of leather or of double canvas. The upper end of the bag should be firmly tied with a cord in a groove gouged out of the rim of the board at A. Into this board is fixed the fork of the piston rod, and the bag is kept distended by a number of wooden hoops or rings of wire, fixed to it at a few inches distance from one another, and kept at equal distances by three or four cords binding them together and stretching from the top to the bottom of the bag. Now let this trunk be immersed in the water: it is evident that if the bag be stretched from the compressed form which its own weight will give it by drawing up the piston rod, its capacity will be enlarged, the valve A will be shut by its own weight, the air in the bag will be rarefied, and the atmosphere will press the water into the bag. When the rod is thrust down again, the water will come out at the valve A, and fill part of the trunk. A repetition of the operation will have a similar effect; the trunk will be filled, and the water will at last be discharged at the spout.

_Bellows-pump_ (Page 186). This is an atmospheric pump in which the part of the piston is played by the top leaf of the bellows. A very simple method of describing an invention, from which great good in drainage of waste lands in Europe, was realized. “There was of course a valve covering the interior orifice of the nozzle and opening outwards, to prevent the air from entering when the upper board was raised. This valve is not shown because the art of representing the interior of machines by section, was not then understood, or not practiced. The lower board is fastened to the ground by a platform while the suction pipe dips into the water. A weight is placed on the upper board to assist in expelling the water.”

Fig. 169 represents a _Double Lantern Bellows-Pump_ as used in the 16th century. This engraving is plain and requires no description. Fig. 170 shows a diaphragm pump in which a sheet of rubber or its equivalent is used as a substitute for a piston in a cylinder.

NOTE.—When an ox or a horse plunges his mouth into a stream, he
dilates his chest and the atmosphere forces the liquid up into his
stomach precisely as up the pipe of a pump. It is indeed in imitation
of these natural pumps that water is raised in artificial ones. The
thorax is the pump; the muscular energy of the animal, the power that
works it; the throat is the pipe, the lower orifice of which is the
mouth, and which he must necessarily insert into the liquid he thus
pumps into his stomach. The capacious chest of the tall camel, or of
the still taller cameleopard or giraffe, whose head sometimes moves
twenty feet from the ground, is a large bellows-pump which raises
water through the long channel or pipe in his neck. The elephant
by a similar pneumatic apparatus, elevates the liquid through that
flexible “suction pipe,” his proboscis; and those nimble engineers,
the common house-flies, raise it through their minikin trunks in the
manner of the gigantic animals which in remote ages roamed over this
planet, and which quenched their thirst as the ox does. There could
have been none which stood so high as to have their stomachs thirty
feet above the water they thus raised into them.

_Rope Pump._ This machine consists of one or more endless ropes, all stretched on two pulleys as shown in Figs. 171 and 172. These pulleys have grooves formed in their surfaces for the reception of the ropes. A rapid rotary motion is communicated to the upper pulley, by a multiplying wheel, and the ascending side of each rope carries up the water absorbed by it, and which is separated from it while passing over the upper pulley, partly by centrifugal force, and partly by being squeezed in the deep groove.

In the beginning of the motion, the column of water adhering to the rope, is always less than when it has been worked for some time, and continues to increase till the surrounding air partakes of its motion. By the utmost efforts of a man, nine gallons of water were raised by one of these machines from a well, ninety-five feet deep, in one minute. (_Adam’s Philos._)

_The hydraulic belt_ is a similar contrivance. It is an endless double band of woolen cloth, passing over two rollers, not here shown. It is driven with a velocity of not less than a thousand feet per minute; when the water contained between the two surfaces is carried up and discharged as it passes over the upper roller, by the pressure of the band. Some machines of this kind are stated to have produced an effect equal to seventy-five per cent. of the power expended, while that of ordinary pumps seldom exceeds sixty per cent. (_Lon. Mechan. Mag._)

_Spray Pump._ Fig. 173 exhibits a carefully designed pump made to spray trees, plants, etc. All the working parts are of brass, the valves are metal; the air chamber is made of galvanized iron or copper and has large capacity. It will hold sufficient compressed air to keep the spray going from six to ten minutes after the pumping stops. The “agitators” are placed so that they keep the liquid thoroughly stirred. The plungers can be easily removed and packed without the necessity of taking the pump to a shop.

The pump is fastened to the bottom of the barrel by a bolt passing through the barrel and secured by a nut underneath, with packing to prevent leakage, and by an iron plate at the top covering the opening through which the pump is placed in the barrel. This pump is arranged with one, or two levers, and for one or two lines of discharge hose. The cylinders are 2-1/2 inches diameter with stroke 3 inches; its capacity per stroke is 0·13 gal.

_Combined Pump and Horse Power._ The “horse power” (apparatus) with its “pole” for one horse and two poles for two horses and its wrought iron “tumbling shaft” has been so modified that a horse operates the pump, by means of a “sweep,” direct connected to the pump crank shaft.

The animal will make three to four circuits per minute, giving the pump crank shaft a speed of 40 to 50 revolutions per minute. The capacity of a 4 in. plunger and 8 in. stroke is given as 3·120 gallons per hour; the suction pipe is given as 3-1/2 in. diam. and the discharge as 3 in. pipe.

DRIVEN OR TUBE WELLS.

Aside from the wells described on page 45 and those following it, there are wells made by forcing iron tubing down into the earth until a water supply is reached. Within reasonable distances and in a remarkably large proportion, these pipe wells are directly connected with the suction part of hand pumps.

NOTE.—“When a well fails to yield a fair amount of oil or water,
an increase in the flow is often effected by means of the Roberts
torpedo. This is a thin water-tight cylinder of metal or paper,
4 to 6 ft. long and 2 or 3 in. in diameter, charged with powder,
gun-cotton or nitro-glycerine. It is lowered to the bottom of the
well, or to a depth that will bring it opposite the desired stratum,
and the well is then flooded. The charge is exploded by a cap or
electric spark, and the explosion often clears away the obstruction
from the oil or water vein. This applies particularly to deep wells.”

To this class also belong the famous oil and artesian wells which penetrate through earth and rock thousands of feet, many of them operated by power pumping machines.

The process of driving tube-wells resembles pile-driving, but with this distinction, that while piles receive the blows of the “monkey” on their heads, the tubes are not struck at all, the blow being communicated by the clamp, which receives the blow near the ground. The tube-well, as in ordinary use, is not intended for piercing rock or solid formations, but is quite capable of penetrating very hard and compact soils, and can be also successfully driven through chalk, breaking through the flints which may obstruct its passage downward. When solid masses of rock or stone are reached, special means of drilling have to be provided for it. When coming upon rock or stone, the best plan is to pull up the tube and try in another spot. This applies also when deep beds of clay are driven into; for, by going a little distance off, and testing again, in many cases water will be found.

The operation is as follows: The first or pioneer tube, shown in Fig. 175 is furnished with a steel point of bulbous form, and perforated with holes varying from one-eighth to an inch, extending from 15 in. to 3 ft. from the point, Fig. 178. The enlargement of the point serves to clear a passage for the couplings by which the tubes are screwed together. On this tube the clamp Fig. 176 is held about 3 ft. from the point by two bolts; the clamp is of wrought iron with steel bushing screwed internally so as to form teeth to grip the tube. Next, the cast-iron driving-weight or monkey is slipped on to the tube above the clamp. The monkey is operated with ropes.

_Sucker-Rod Couplings._ These couplings are usually made of iron galvanized and are used to connect the ends of wooden sucker rods for deep well pumps. Each half of coupling is secured to the end of wooden rods by three bolts; the ends of the couplings are joined by male and female threads in the usual way.

Either bolts or rivets may be used to attach the rods to the couplings. (See Fig. 179.)

POINTS FOR ERECTING AND OPERATING HAND PUMPS.

_Foundation_—For the smaller sizes a foundation is not necessary, other than a good floor. With the large sizes it is advisable to have a substantial foundation. Concrete, well rammed into place, surmounted by a capstone, is as good as any. The foundation allows the pump to be run at a higher speed; a plan showing location of bolt-holes, position of flanges, and general dimensions, so that there may be no delay in setting the pump upon arrival at its destination.

_Suction Pipe_—The suction pipe should be as short and direct as possible, avoiding all turns not necessary. Place a strainer and foot-valve, Fig. 180, on the suction pipe. It is better for the pump to have a slight suction except when hot water is pumped, than to supply the water to the pump under a slight head.

_Discharge Pipe_—Make the discharge piping as straight as possible, using long bends.

_Packing_—The stuffing boxes should be carefully packed and the gland brought up firmly against the packing; screwing up the gland by hand should be sufficient.

Large sizes of suction and discharge pipe are desirable, because the friction of the water in the pipes thus reduced makes the pump work easier.

POWER PUMPS

POWER DRIVEN PUMPS.

By _a power-driven pump_ is meant one actuated by Belt, Rope-transmission, Gear, Shafting, Electric-motor, Water-wheel, Friction, or by direct connection to a power shaft. It thus becomes very frequently a question which apparatus is most desirable.

These are classified, thus—

1. Single power pumps,
2. Duplex power pumps,
3. Triplex (triple) power pumps,
4. Quadruplex, etc. Where the sizes still

further increase they are named from the number of barrels or water cylinders, but when of much larger size than the Triplex they come under the classification of pumping engines.

Where power can be had from a shaft in motion there is no pump so economical as the power or belt driven pump. This fact is shown by the rapid increase in the number of applications of this type of pump: the reduced cost of manufacture in making the teeth of the gear wheels, the use of automatic machinery, the production of interchangeable parts have tended to produce a high grade of machine at an attractive price.

The energy expended in operating the power driven pump is obtained at the same economy as that required by the machinery in the mill or factory, and as a modern automatic cutoff engine will develop a horse power with considerable less steam than the direct acting steam pump the cost of the power required by the power driven pump is correspondingly less; it participates in the economy of the steam engine using from one and a half pounds of coal to five or six pounds per H. P. per hour.

For this reason the power driven pump is oftentimes the more economical, and especially where shafting is adjacent to the location of the pump, or can be conveniently arranged by simply adding another length of shafting with the necessary pulleys, or even by cutting suitable openings through the walls for the belts.

_Single, duplex and triplex power pumps_ are described and illustrated upon the succeeding pages; power pumps are built with one, two, three, four or five cylinders and for either high or low pressure or general service, and their sizes, capacities, and the materials they handle are no more numerous than their combinations in erection.

The portion of this work devoted to power pumps should be especially interesting and instructive to the attendants operating steam, compressed air and power driven pumps. Particular attention has been given to _single-cylinder steam pumps_ because of the great variety of steam-actuated valves to be found in practice, each differing from the other in one or more essential features.

It is due very largely to the numerous designs of steam valves, that difficulty has been encountered in managing single-cylinder pumps as successfully as those of the duplex type, the similarity of construction in the latter type, even in minor details, being much more marked.

The successful operation of a pump depends to a great extent upon the intelligence displayed in its management, and an engineer can scarcely hope to obtain quiet and smooth running pumps and freedom from breakdowns and perplexing delays except by a thorough knowledge of the details of construction and operation.

It must be remembered that _power pumps_ are to be illustrated and explained in a class entirely excluding _steam pumps_; the latter are pumps in which the moving force is steam.

_Electric Pumps_ are properly power pumps in which the moving force is _electricity which is conducted to the pumps by wires_.

PUMP PARTS.

_Water Ends._ There are properly speaking four kinds of water ends to steam and power pumps:

1, A solid plunger, with a stuffing box used for heavy pressings in hydraulic apparatus, or as shown in Fig. 182, for larger plungers.

2, A piston packed with fibrous material within the cylinder. See Fig. 181. The letter P in Fig. 182 and the following cuts indicates the plunger.

3, A plunger packed with a metal ring around the outside, as illustrated in Fig. 183.

4, Two plungers, Fig. 184, connected outside of the cylinder with a stuffing box in two cylinder heads, through which the plungers work. These are more fully explained and illustrated as they occur in many examples as they are referred to in the oncoming chapters of this work.

The construction of the water ends of single cylinder and duplex pumps is practically the same; any slight differences which may be found are confined to minor details, which in no way affect the general design or operation of the pump.

_The steam or power ends_ of numerous and varied makes of pumps are also as shown in the following pages of this work; all pumps actuated by power—steam, electric, etc.—are possessed of these two distinguishing features—1, a steam or power end, and 2, the water end.

NOTE.—This statement has exception in the cases of large pumping
engines having a fly wheel or supplemental cylinders attached to
an accumulator, in which case the steam is worked expansively.

_The steam end of the ordinary single steam pump, and also of the duplex pump, differs from the steam cylinder of the steam engine in that the former has four ports to each cylinder, i. e., two steam ports and two cushioning ports as shown hereafter in figures._

Under the division of the work allotted to the “Steam Pump” will be found all necessary further notice of the steam ends of Pumps.

_Pump Valves._ The valve apparatus is perhaps the most important part of any form of pump and its design has a material bearing upon its efficiency.

The valves shown in Fig. 181 are carried by two plates or decks, the suction valves being attached to the lower plate and the delivery valves to the upper one. The upper deck, and sometimes both decks, are removable. The valves are secured to the plates by means of bolts or long machine screws, which, in turn, are screwed into the bridge across the board in the plate, as shown in Figs. 185 and 186 or capped as in Fig. 187. The valves in all pumps except the large sizes, which may properly be classed with pumping engines, are of _the flat rubber disc type_, with a hole in the center to enable the valve to rise easily on the bolt, the latter serving as a guide. _A conical spring_ is employed to hold the valve firmly to its seat, the spring being held in position by the head of the bolt, or cap, as shown.

Certain improvements in pump-valves have been made which tend to increase the durability and to prevent the liability of sticking, which is not an uncommon occurrence after the valves have become badly worn. The improved forms of pump valves are shown in Figs. 186 and 187.

When these valves leak through wear the disc may be reversed, using the upper side of the disc next to the valve seat. This can be done with ordinary valves also, provided the spring has not injured the upper surface of the disc. Valve seats are generally pressed into the plates, although instances may be found where they are screwed. When pressed in they may be withdrawn by substituting a bolt having longer screw threads than the regular bolt, and provided with a nut, as shown in Fig. 188. The bolt is slipped through a yoke and screwed into the bridge. By turning the nut the seat can generally be started without difficulty.

Fig. 189 represents the customary _gland and stuffing-box_ in which the gland is adjusted by the nuts C and D upon two studs. After the adjustment has been properly made lock-nuts are tightened which leaves the gland free yet preserves the alignment.

It has been proven by practice—after long and costly experiments—that a number of small valves instead of one large one are far the most durable; _durability_ being the question. Corliss, Leavitt, Holly and other leading pump builders had occasion to find the truth of this statement early in their careers. The “slamming” of large valves under moderate speeds proved itself an almost insurmountable difficulty until the principle of keeping the valve area as low as possible within reasonable limits had been fully demonstrated.

To illustrate the advantage of having a number of comparatively small valves instead of one large one, suppose a pump to be fitted with four 3-1/2-inch delivery valves at each end, the valves covering ports 2-1/2 inches in diameter. The area of each port is 4·9 square inches. In order to provide an equal area between the valve and the seat the valve must rise a distance equal to one-fourth the diameter of the port.

The combined area of the four ports is 19·6 square inches, which corresponds to the area of a circular opening 5 inches in diameter, one-fourth of which is 1-1/4 inches. It will be understood that the smaller valves can seat much more quickly and with less jar than the larger one, hence a larger number of small valves is not only better because of the great reduction in slippage, but they are also more economical, being subjected to less wear and tear.

_The lift of valves_ for moderate or low speed pumps is seen in Fig. 190 and those for higher speeds in Fig. 191. These engravings clearly show the relative position of the suction and discharge valves during the movements of the piston.

_Pump slip_ or slippage is a term used to denote the difference between the calculated and the actual discharge of a pump, and is generally expressed as a percentage of the calculated discharge. Thus, when the slippage is given as 15 per cent. it indicates that the loss due to slip amounts to 15 per cent. of the calculated discharge. Slippage is due to two causes, the time required for the suction and discharge valves to seat.