FLUID, HYDRAULICA fluid suitable for
use in a hydraulic system.
FLUID, PETROLEUMA fluid composed
of petroleum oil. It may contain additives.
FLUID, PHOSPHATE ESTER BASEA
fluid that contains a phosphate ester as one of the
FLUID, SILICONEA fluid composed of
silicones. It may contain additives.
FLUID, WATER-GLYCOLA fluid whose
major constituents are water and one or more
glycols or polyglycols.
FLUID STABILITYResistance of a fluid to
permanent change in properties.
FLUID POWEREnergy transmitted and
controlled through the use of fluids under
FLUID POWER SYSTEMA system that
transmits and controls power through use of a
pressurized fluid within an enclosed circuit.
FOOT-POUNDThe amount of work
accomplished when a force of 1 pound produces
a displacement of 1 foot.
FORCEThe action of one body on another
tending to change the state of motion of the body
FREE FLOWFlow that encounters negli-
FRICTIONThe action of one body or
substance rubbing against another, such as fluid
flowing against the walls of pipe; the resistance
to motion caused by this rubbing.
FRICTION PRESSURE DROPThe decrease
in the pressure of a fluid flowing through a
passage attributable to the friction between the
fluid and the passage walls.
GASThe form of matter that has neither a
definite shape nor a definite volume.
GASKETA class of seals that provides a seal
between two stationary parts.
GAUGEAn instrument or device for
measuring, indicating, or comparing a physical
GAUGE PRESSUREPressure above
GAUGE SNUBBERA device installed in
the line to the pressure gauge used to dampen
pressure surges and thus provide a steady reading
and a protection for the gauge.
GAUGE, BELLOWSA gauge in which the
sensing element is a convoluted closed cylinder.
A pressure differential between the outside and
the inside causes the cylinder to expand or contract
GAUGE, BOURDON TUBEA pressure
gauge in which the sensing element is a curved
tube that tends to straighten out when subjected
to internal fluid pressure.
GAUGE, DIAPHRAGMA gauge in which
the sensing element is relatively thin and its inner
portion is free to deflect with respect to its
GAUGE, PRESSUREA gauge that
indicates the pressure in the system to which it
GAUGE, VACUUMA pressure gauge for
pressures less than atmospheric.
GRAVITYThe force that tends to draw all
bodies toward the center of the earth. The weight
of a body is the resultant of gravitational force
acting on the body.
HEADThe height of a column or body of
fluid above a given point expressed in linear units.
Head is often used to indicate gauge pressure.
Pressure is equal to the height times the density
of the fluid.
HEAD, FRICTIONThe head required to
overcome the friction at the interior surface of
a conductor and between fluid particles in motion.
It varies with flow, size, type, and condition of
conductors and fittings, and fluid characteristics,
HEAD, STATICThe height of a column or
body of fluid above a given point.