Chapter 2 Fluid Power Systems 43
through the filter element, which removes con-
taminates, and is then directed back into the sys-
tem through the outlet port. If the filter element
becomes clogged with contaminants, the bypass
valve opens and routes fluid around the filter
element.
A pneumatic system includes two additional
fluid conditioning devices: a separator and a
lubricator. The separator removes water droplets
from the compressed air. The filter and separator
are often combined in one unit called a separator-
filter. The lubricator adds a fine mist of oil to the air
for lubrication of system components, Figure 2-18.
The hydraulic system reservoir also serves as
an important component for fluid maintenance. A
well-designed reservoir helps control temperature
by dissipating heat, trapping contaminants, and
allowing air trapped in the system oil to separate
and escape.
The receiver also serves as a fluid maintenance
device in the pneumatic system. The receiver
allows water droplets and other contaminates to
settle out of the compressed air. The device also
helps control the temperature of the system by
allowing heat to dissipate.
Basic System Operation
Individual fluid power components must be
assembled into a system to convert, distribute, and
control the energy provided by the prime mover
and produce the work desired from a machine. The
basic systems described in this section include com-
ponents from each of the five component groups
and provide directional, pressure, and speed con-
trol of an actuator. Basic system examples are pro-
vided for both hydraulic and pneumatic systems
to illustrate the structural characteristics of each
system and the inherent differences between the
systems.
Basic Hydraulic System
A basic hydraulic system is illustrated in
Figure 2-19. The system includes an electric motor
that serves as the prime mover. The prime mover
produces the energy needed to operate the system
and perform the work required of the actuator.
The system contains basic components from each
of the component groups to allow operation and
control of a cylinder.
As the electric motor turns the pump, pres-
sure differences are created within the system.
Figure 2-17. Filters, such as this compressor inlet
fi lter, are used in several locations in both hydraulic
and pneumatic systems to remove contaminates,
which increases both the performance and service
life of system components. (Photo: Atlas Copco)
Figure 2-18. A lubricator in a pneumatic system
adds a fi ne mist of oil to the compressed air
before it is used at a system workstation.
(Photo: Atlas Copco)