PRIME MOVERThe source of mechanical
power used to drive the pump or compressor.
PUMPA device that converts mechanical
force and motion into hydraulic fluid power.
PUMP, AXIAL PISTONA pump having
multiple pistons disposed with their axes parallel.
PUMP, CENTRIFUGALA pump that
produces fluid velocity and converts it to pressure
head.
PUMP, FIXED-DISPLACEMENTA
pump in which the displacement per cycle cannot
be varied.
PUMP, RADIAL PISTONA pump having
multiple pistons disposed radially actuated by an
eccentric element.
PUMP, VARIABLE-DISPLACEMENTA
pump in which the volume of fluid per cycle can
be varied.
RANKINE SCALEA thermometer scale
based on absolute zero of the Fahrenheit scale,
in which the freezing point of water is
approximately 492°R.
RATIOThe value obtained by dividing one
number by another, indicating their relative
proportions.
RECEIVERA container in which gas is
stored under pressure as a supply source for
pneumatic power.
RECIPROCATINGMoving back and
forth, as a piston reciprocating in a cylinde.,
RESERVOIRA container for storage of
liquid in a fluid power system.
RESPONSE TIMEThe time lag between a
signal input and the resulting change of output.
RESTRICTORA device that reduces the
cross-sectional flow area.
RESTRICTOR, ORIFICEA restrictor, the
length of which is relatively small with respect to
its cross-sectional area. The orifice may be fixed
or variable. Variable types are noncompensated,
pressure compensated, or pressure and tempera-
ture compensated.
RETURN LINEA line used for returning
fluid back into the reservoir or atmosphere.
SEPARATORA device whose primary
function is to isolate undesirable fluids and or
contaminants by physical properties other than
size.
SERVOA device used to convert a small
movement into a greater movement of force.
SOLIDThe form of matter that has a
definite shape and a definite volume.
SPECIFIC GRAVITYThe ratio of the
weight of a given volume of a substance to the
weight of an equal volume of some standard
substance.
STEADY FLOWA flow in which the
velocity, pressure, and temperature at any point
in the fluid do not vary with time.
STRAINERA coarse filter.
STOKEThe standard unit of kinematic
viscosity in the cgs system. It is expressed in square
centimeters per second; 1 centistoke equals 0.01
stoke.
STUFFING BOXA cavity and closure with
manual adjustment for a sealing device.
SUPPLY LINEA line that conveys fluid
from the reservoir to the pump.
SURGEA momentary rise of pressure in a
circuit.
SYNCHRONIZETo make two or more
events or operations occur at the proper time with
respect to each other.
SYNTHETIC MATERIALA complex
chemical compound that is artificially formed by
the combining of two or more simpler compounds
or elements.
TANKA container for the storage of fluid
in a fluid power system.
THEORYA scientific explanation, tested by
observations and experiments.
THERMAL EXPANSIONThe increase in
volume of a substance due to temperature change.
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