Doc No: OMM50001243
Rev: C Page 64 of 68
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and may not be reproduced, disclosed, or made public in any manner prior to express written authorization by TechnipFMC.
FLOODED SUCTION
Implies that the level of liquid in the suction
vessel is above the centerline of the suction
port of the pump.
FLUID END
The portion of the pump that converts the linear
motion supplied by the power end into fluid flow
at pressure. This may also be called the Liquid
End. It is called a valve chamber in old
literature.
NPSHa
An abbreviation that stands for "Net Positive
Suction Head Available". NPSHA is the total
suction pressure, including allowance for
acceleration head, available from the system at
the pump suction connection, minus the vapor
pressure of the liquid at actual pumping
temperature. NPSHA for a reciprocating pump
is expressed in units of feet of water or meters
of water.
NPSHr
An abbreviation that stands for "Net Positive
Suction Head Required". This is the minimum
total inlet pressure required by the pump for
proper operation. This value is a function of
pump design and speed and is determined by
the pump manufacturer through a specific
NPSH test. NPSHa should exceed NPSHr by
at least 5 feet (1.5 m) for water and other
incompressible liquids or 3 feet (1.0 m) for light
hydrocarbons.
PISTON
A type of power pump that uses a cylindrical
seal (piston) mounted on a holder to drive fluid
through the valves. The piston seal
reciprocates within a stationary cylinder.
PLUNGER
A type of power pump that uses a cylindrical
plunger to drive fluid through the valves. The
plunger reciprocates through a stationary set of
seals known as packing.
POWER PUMP
A reciprocating pump that drives the pumping
element(s) using a slider crank mechanism.
Power pumps are piston, plunger, or diaphragm
type. All require a driver with a rotating shaft,
such as a motor or engine, as a power source.