16 Fluid Power
Definition of Fluid Power
The basis of fluid power is pressurized fluids.
These fluids may be either liquids or gases. The
fluids are incorporated into physical hardware
systems that generate, transmit, and control power
in a wide variety of consumer and industrial appli-
cations. Today, it would be difficult to identify a
product that has not been affected by fluid power
at some point along the route from raw material to
final installation.
Fluid power systems are versatile contributors
to industry. Applications range from brute force
needed in heavy industry to the sensitive position-
ing of parts in precision machining operations,
Figure 1-1. The systems are generally grouped
under the two broad classifications of pneumatic
and hydraulic. Pneumatic systems use gas, usu-
ally air, while hydraulic systems use liquids, usu-
ally oil. Other fluids are often used in special
applications.
Fluid power is one of the three types of power
transfer systems commonly used today. The other
systems are mechanical and electrical. Each of
the systems transfers power from a prime mover
(source) to an actuator that completes the task
(work) required of the system.
Fluid power systems use the prime mover to
drive a pump that pressurizes a fluid, which is then
transferred through pipes and hoses to an actua-
tor, Figure 1-2. Mechanical systems transfer power
from the prime mover to the point of use by means
of shafts, belts, gears, or other devices. Electrical
systems transfer power using electrical current
flowing through conductors. Typical applications
in business, industrial, and consumer products
and systems use combinations of fluid, mechani-
cal, and electrical power transfer methods.
Fluid Power Industry
The fluid power industry is a complex entity.
It includes education, design and manufacture of
components, design and assembly of systems using
those parts, and troubleshooting and maintenance
needed to keep the systems performing efficiently,
Figure 1-3. In addition, a complex sales and distri-
bution system assures users access to replacement
components and information concerning service,
new and improved component designs, and new
system applications.
Figure 1-1. Equipment used in construction and
street maintenance is an example of a fl uid power
application commonly encountered in daily life. This
backhoe is capable of producing the brute force
needed to break and move concrete.
(Deere & Company)
Figure 1-2. Many consumer items make use of
fl uid power in their operation. This garden tractor
has a hydrostatic transmission, as well as several
other fl uid power accessories.
(MDMA Equipment–Menomonie)