===============+=============+==================+======+==========
PLUNGERS |Capacity one | SIZES OF PIPE | | Tight
---------------+Revolution of+--------+---------+Geared|and Loose
Diameter Stroke| Crank Shaft |Suction |Discharge| | Pulleys
---------------+-------------+--------+---------+------+----------
4 in. 4 in.| 0·65 gals. | 3 in. | 3 in. |5 to 1|20 × 3 in.
4 „ 6 „ | 1· „ | 3 „ | 3 „ |5 to 1|20 × 3 „
5 „ 6 „ | 1·5 „ | 4 „ | 4 „ |4 to 1|20 × 4 „
5 „ 8 „ | 2· „ | 4 „ | 4 „ |4 to 1|20 × 4 „
7 „ 8 „ | 4· „ | 5 „ | 5 „ |4 to 1|30 × 5 „
8 „ 10 „ | 6·5 „ | 6 „ | 6 „ |5 to 1|36 × 6 „
8 „ 12 „ | 7·8 „ | 6 „ | 6 „ |5 to 1|36 × 6 „
---------------+-------------+--------+---------+------+----------
_The Deane single acting triplex power pump_ is shown in Fig. 213.
Pumps of this type are used for general service in places where a large
quantity of water is to be obtained in a short time and delivered under
high pressure; they are adapted for tank service, water works, boiler
feed, etc.
[Illustration: FIG. 213.]
The pillar, or column design of frame is employed in this pump which
secures great strength with the least weight of material, and at
the same time is accessible for adjustment or repairs. The bearings
for both the steel shafts are unusually long, which reduces the
pressure per square inch below the factor of safety and increases the
durability. The crankpins are set 120 degrees with one another so that
the strokes successively overlap, which promotes an easy flow of water
through the delivery pipe. The crank shaft is of the composite design,
the center crank pin is of equal diameter and forming a part of the
shaft, with discs and crank pins attached to each end by shrinking fits
and keys. Either disc, crank, or their crank pins, can be duplicated
without sacrificing any other part, which in itself is a great
advantage.
The connecting rods have solid ends with adjustable boxes, with
adjustment by means of wedge and screws. The brasses are lined with a
special anti-friction metal bored to exact size.
The crossheads are of the box design with adjustable shoes having large
wearing surfaces in bored guides. These guides are secured to the frame
by studs and nuts.
The plungers are outside packed, the cylinders are submerged, thus
keeping the pump primed at all times. The plungers are bolted to the
crossheads and are readily removed when necessary. The cylinders are
single acting and are cast separate from the base and other parts
of the machine, so that repairs can be made at small cost, and,
furthermore, should it be desirable to use the pump for moving liquids
which would be injurious to cast iron, cylinders of other metals are
substituted. The water chest is cast separate from the cylinders and is
provided with large handholes, affording easy access to the interior
and to the valves for inspection and cleaning. The handholes are
located so that one valve may be removed independent of the others.
Improved grease cups are placed on all the bearings. This pump is very
popular with the users of power driven pumps and is generally selected
for high pressures and for hot or gritty water. Its simplicity of
design and construction, together with the convenient arrangement of
working parts, renders it desirable in isolated places where little
attention is given to any kind of pumps.
[Illustration: FIG. 214.]
Fig. 214 represents the Gould triplex single acting power pump and is
one of many designs of this class of power pumps. The frame consists of
two standards, which contain the two end cylinders, and the seats to
which the outside crosshead guides are bolted. These are held together
by two castings, one containing the center crosshead guide, and the
other the center cylinder. The crankshaft is a solid steel forging,
while the bearings are of phosphor bronze, and the pinion shaft
bearings Babbitted.
The gear wheels are machine cut, the pinion and the adjacent teeth of
the large gear are covered by suitable guards.
The crossheads are provided with adjustable shoes or gibs, which work
in bored guides. The connecting rods are fitted with straps and bronze
boxes, which are adjustable for wear by means of wedge and set screws,
the wristpin brasses being of the marine type. The cylinders are
provided with bronze liners, which are readily removable when necessary
for repairs, the plungers being ground to size, present a smooth
polished surface to resist the wear.
The valve boxes are separate castings, and each contains a set of
suction and discharge valves. These valves are rubber discs, held
firmly against the bronze seats by cylindrically wound springs. All
of these pumps are furnished with air chambers, and vacuum chambers
are provided when the nature of the service demands it. All valves and
other working parts of the pump are accessible for inspection, cleaning
and repairs, all internal parts being arranged within easy reach
through the large handholes.
The pumps here shown are intended for moderately light pressures as for
example not to exceed 150 lbs. per square inch, but they are also made
in heavier proportions for very high pressures (5,000 lbs. to 15,000
lbs.) such as is necessary to operate hydraulic presses, draw benches
for brass and copper tubing and that class of work.
A very simple automatic regulator and by-pass connection (shown in the
chapter on accessories) can be attached to these pumps in situations
where a constant pressure is to be maintained and allow the pump to run
continuously at its maximum speed. This regulator is adjusted to open
the by-pass valve whenever the pressure in the compression tank or pipe
system exceeds the limit pressure, and so fills the office of a safety
valve by allowing the surplus water to return to the tank.
_The Riedler belt driven pump_ is shown in Fig. 215.
The principal feature of this pump is its valve; there is but one valve
for the suction and one for the discharge, which greatly simplifies
the pump end. When working against high pressures, the ordinary rubber
or leather faced valves are oftentimes pounded to pieces, but in this
pump, on account of the mechanical control, the valves work well under
all pressures.
[Illustration: FIG. 215.]
This valve and valve seat are circular in form, and made of bronze, as
shown in Fig. 216. The valve has a lift of from 1 to 2 inches, and an
area sufficiently large to reduce the velocity of the water flowing
through it to a few feet per second.
At the beginning of the stroke the valve opens automatically,
controlled, however, by a very simple and effective mechanical device,
and it remains open practically during the entire stroke. When near the
end, it is positively closed at the proper moment by the controller.
This valve, see Fig. 216, may be briefly described as follows. The
seat, A, is turned to slip into its place in the pump and is made tight
by a round rubber hydraulic packing, B, in a groove near the bottom.
A spindle or stud, C, in the center of this seat supports and guides
the valve, D, which is made tight by a leather seal, E. The rubber
collar or buffer spring holds the valve above its seat, and this valve
unlike ordinary pump valves, always remains open except when pressure
is brought to bear to close it. The valve bonnet, G, also forms the
bearing for the valve stem with fork, which spans the spindle, C, at
one end and having the valve lever and pin, H, for operating at the
other end. The valve stem is made tight by a stuffing-box and gland as
shown. The operation of this valve is substantially as follows.
[Illustration: FIG. 216.]
At the beginning of the suction stroke the valve is opened by the
rubber spring, F, the pressure upon the collar being relieved by
lifting of the valve fork arms through motion of the eccentric.
It will be observed from an inspection of Fig. 215 that both
the suction valve and the discharge valve are controlled by an
eccentric—rock arm—and valve levers similar to the motion of _Corliss_
valves.
As the plunger nears the end of its stroke and before it starts on the
return stroke, the valve fork closes the valve, and thus prevents slip
and avoids pounding, so common in pumps having valves that close by
their own weight. In case of any obstruction between the valve and its
seat the rubber buffer spring will be compressed thus preventing all
injury to mechanism.
The lost work expended in closing the valves is hardly worth any
consideration as it is practically the friction only of the eccentric
and the members of the valve gearing, the bearings of which are all
small.
The motion for these valve gears is usually taken from an eccentric on
the main shaft.
The standard speed of the Riedler pumps is about 150 revolutions per
minute. Smaller pumps run even faster than this.
It may be desired to connect a pump directly to a high speed electric
motor or water wheel already installed. To meet these conditions, a
special design known as the Riedler Express pump, is built.
The chief feature of this pump, is its suction valve. This valve is
concentric with, and outside of the plunger, and lifts in the opposite
direction to that of the plunger when on its suction stroke. At the end
of the suction stroke, the plunger presses the valve to its seat, thus
making it certain that the valve is seated when the plunger starts on
its delivery stroke, allowing practically no slip. A high air suction
chamber containing a column of water is placed immediately before the
suction valve, so it is certain that the pump will fill as the plunger
moves. Ordinarily the pump would not completely fill, owing to the high
speed of the plunger.
These pumps are also built with steam cylinders both of the plain slide
valve and Corliss designs.
THE ELECTRIC
PUMP
[Illustration: COMPASS NEEDLE—See PAGE 266.]