46 Fluid Power
As the electric motor turns the compressor,
pressure differences are created within the system.
As a result, atmospheric air enters the compressor
through an intake-line filter that removes airborne
dirt. The compressor compresses the air and forces
it into an air receiver. The air is held in the receiver
in compressed form until it is distributed through
lines to other system components. See Figure 2-24.
A pressure switch controls the prime mover. The
compressor functions only when additional air
is needed to maintain the desired pressure in the
receiver and the distribution lines leading to sys-
tem workstations.
The first system component the compressed air
encounters after it moves out of the receiver through
system lines to a workstation is a separator-filter.
See Figure 2-25. This component removes droplets
of condensed water and any remaining dirt parti-
cles. The air then moves to a regulator, which con-
trols the operating pressure at the workstation. The
operating pressure maintained by the regulator is
always less than the pressure at the receiver.
High-pressure oil flow
Low-pressure oil flow
Non-flowing, high-pressure oil
Non-flowing, low-pressure oil
A
Figure 2-22. Oil fl ow through a basic hydraulic system when the
cylinder is fully extended or retracted or when it encounters a
load heavier than it can move. A—Fully extended or stalled on
extension. B—Fully retracted or stalled on retraction.
High-pressure oil flow
Low-pressure oil flow
Pressurized oil
Non-pressurized oil
B