Centrifugal Pumps Terms
A circumstance in which a centrifugal body is so full of air that a vacuum
can no longer be formed. Without vacuum, water cannot flow into the pump.
– The force
applied by the atmosphere to the surface of the earth. Atmospheric pressure,
the standard of which is 14.7 lbs per square inch, affects the operation
of a pump.
– A term describing
how much water a pump can process. Capacity is typically articulated as
gallons per hour (gph) or gallons per minute (gpm).
– An undesirable
condition in which vacuum pockets form within the pump. The air pockets
eventually implode under pressure, resulting in the pitting of the impeller
and volute surfaces.
– The force
that causes a substance to move away from its center of rotation.
– An apparatus in a discharge or suction line that permits flow
in only one direction so as to prevent reverse flow and isolate the material
– The removal of
unwanted dirty or clear water containing no hazardous materials.
– A stationary casing,
like a volute, that houses the moving impeller. Diffusers are compact
in design, enabling the pump to create higher pressure heads.
– A collapsible
hose that moves the discharged water from the pump.
– Also called
the “outlet,” it is the point at which the discharge pipe
or hose is connected to the pump.
– Detachable plugs
for draining water from the pump when it is inactive.
– Acting by motion,
not weight, in contrast to static.
– The head or pressure
force against which the pump operates.
known as “total suction head,” it is the combination of the
static suction lift and the suction friction loss in the suction line.
– Partially or completely
treated wastewater or other liquid that flows out of a septic tank or
– Rubber molded
around a steel weight that seals off the inlet or outlet, preventing water
from either entering or exiting the pump at the wrong time.
– The required amount
of gallons per minute (gpm) of pump flow. Flow can also be expressed in
gallons per hour (gph) and in million gallons per day (mdg).
– The measure of the pressure
or force exerted by a fluid in a hydraulic system. Also, the height of
fluid above any point, taking into account losses or gains in pressure
due to gravity and friction as water travels through a system, measured
in lbs per square inch (psi) or feet of water.
– A rotating disk with
vanes of varying amounts attached to the “r” drive shaft that
creates centrifugal force within the pump casing of a centrifugal pump.
Impellers can be open or closed.
– The center of
the impeller and the point at which fluid flows into the impeller.
– Pump components
located on the impeller between the eye and the discharge side of the
impeller. Impeller vanes direct the flow of the liquid to the outside
diameter of the impeller.
– The flow, or the rate
of flow, into a pump.
– A device that
forms a seal between the pump and the engine or motor and prevents water
from getting into the engine or motor.
– A measure of the absolute pressure of the liquid at the inlet
of the pump.
– Allowing the pump to
disperse all air from the influent line of a circulating system by causing
fluid to start flowing once again. Priming the pump is usually accomplished
by either manually filing the volute or turning the pump on.
– The body or casing
of a pump, which may be made of plastic, cast-iron, stainless steel or
vibration-dampening devices that are mounted on the engine to prevent
the pump from “walking away.”
– Acting by weight not
motion, in contrast to dynamic.
– A plastic
mesh basket that traps debris to prevent its reaching the impeller. Strainer
baskets are located in the strainer pot.
– The housing of
the strainer basket that is located on the influent side of the pump.
Strainer pots serve as a priming chamber.
– A reinforced
hose through which water flows into the suction end of a pump.
– A type
of cavitation resulting from the small size of the impeller or low cutwater
– The act of removing air
or gas from a system. Stuffing boxes in vertical pumps must be vented
to prevent the seal faces from running dry.
– The resistance to
flow of a liquid at a particular temperature. High viscosity liquids,
such as motor oil, are thick and tend to flow slower than water, a low
– Stationary casing of
a centrifugal pump that separates air and water and in which the impeller
rotates. Volutes are spiral-shaped in order to facilitate the partial
conversion of the velocity (kinetic) energy into pressure head as the
water leaves the impeller.
– Creates a
“whirlpool effect” that can cause air to be drawn into the
suction of the pump.
– A small opening
located on the underside of the pump at which point the engine joins the
pump. Weep holes provide the means to quick detection of a leak before
water seeps into the oil sump of the engine.