The pattern of pump shown in Fig. 306, is especially designed for use
in connection with hydraulic lifts and cranes, cotton presses, testing
machines, hydraulic riveting and punching machines, and hydraulic
presses of all kinds. Also for _oil pipe lines_ (see Table, page 341),
mining purposes, and such services as require the delivery of liquids
under heavy pressures.
There are four single acting outside packed plungers, which work into
the ends of the water cylinders, the latter having central partitions;
each individual valve has its own cover or bonnet. The arrangement
of compound steam cylinders is shown. The water valves are easily
accessible, and are contained in small chambers, capable of resisting
very heavy pressures. The general arrangement shown in the engraving
is subject to numerous alterations, according to various requirements,
_but the general characteristic of four outside packed plungers is in
all cases preserved_.
[Illustration: FIG. 306.]