Chapter 1 Introduction to Fluid Power 21
■ Large volumes of compressed air may be
easily stored in pneumatic systems to pro-
vide energy for intermittent, heavy system
demand, Figure 1-9.
■ Pneumatic systems provide clean operation
with minimal fire hazard.
Disadvantages
The following list of disadvantages applies to both
hydraulic and pneumatic systems, except as noted.
■ Higher safety factors associated with
high-pressure oil and compressed air.
■ Susceptibility to dirty environments, which
can cause extreme component wear without
careful filtration.
■ Fluid leakage and spills cause a slippery,
messy work environment around hydraulic
equipment.
■ Fire hazard with hydraulic systems using
combustible oils.
■ Special handling and disposal procedures
for hydraulic oil required by environmental
regulations.
■ High cost of compressing and conditioning
air for use in pneumatic systems.
■ Reduced accuracy in actuator speed control in
pneumatic systems caused by compressibility
of air.
■ Noise level of pneumatic systems when air
is directly exhausted to the atmosphere from
components.
Historical Perspective of
Fluid Power
Awareness of the historical background of our
civilization, our particular culture, and our nation
are generally considered an important part of the
preparation to be a responsible citizen. This aware-
ness provides an appreciation of our current situ-
ation by providing information about the origin
and development of cultural, religious, and politi-
cal ideas, principles, and systems. Likewise, an
awareness of the historical development of a tech-
nical field of work should provide an appreciation
of what we have, some idea of how it was achieved,
and an appreciation of the cultural changes associ-
ated with the technical field.
This section provides a brief discussion of some
aspects of technical development and innovation
as viewed by Western culture. Volumes of infor-
mation are available on developments throughout
history involving Islamic and Eastern contribu-
tions as well as those reflecting Western thought.
Fluid power, as the term is currently used in our
society, describes a relatively new field. However,
the roots of this field extend far back into history.
Historical Awareness
The use of fluid power has developed along with
civilization. The natural movements of air and water
were probably the first sources of power used by
early humans. It is speculated that the use of crude
sails to reduce the effort to move boats was the first
attempt to harness this natural power, Figure 1-10.
These early applications were followed by the devel-
opment of more sophisticated systems, which even-
tually lead to the development of the windmill.
Receiver
Compressor
Figure 1-9. Pneumatic systems can easily store
large volumes of compressed air to meet the inter-
mittent high demand of some systems. The horizon-
tal tank under the compressor serves as the storage
area for compressed air.