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2.1.4 Suction System
Single acting reciprocating pumps perform best when supplied with an appropriate level of
fluid. Inadequate fluid supplies may lead to cavitations, which is one of the primary causes of
premature pump failure. When setting up the pump, it is very important to ensure that there is
sufficient fluid running through the pump at all times.
The fluid supply tank should be large enough to allow dissolved air and other gases to
escape from the liquid, and allow suspended solids to settle out before entering the pump.
For this reason, a system employing dams and settling chambers is desirable.
Charging Pumps
A centrifugal charging pump should be used to boost fluid supply and ensure proper
operations. This pump should be sized to 150% of the main pump volume for the largest
piston size expected to be used to allow for the varying flow demands of the triplex pump.
The charging pump should be set to ensure the suction manifold pressure is between 20 and
30 PSI to ensure maximum volumetric efficiency and expendable parts life.
The charging pump may be driven using V-belts or chains off the mud pump input shaft,
but this is not recommended as it makes mounting the pump and inlet system piping difficult,
and may not provide sufficient RPMs to the charging pump for proper operation when the
mud pump is operating at lower speeds. For this reason, it is recommended that a booster
pump be used, powered by an electric AC motor.
The mud pump control panel should be configured so that the mud pump cannot be
started until the charging pump is running and has developed at least 20 PSI. For full
operating instructions and guidelines for using a particular charging pump, see the
documentation provided by the manufacturer.
Piping
The suction piping can be connected to any of the available flanged connections on the
suction manifold. The length of the suction piping should be minimized as much as possible
to enhance pump efficiency, and utilize 45° long radius elbows to help reduce frictional
pressure drops at the inlet. The suction piping should be supported to prevent unnecessary
loads on the pump suction manifold.
Common Suction Manifolds
Two or more pumps can have their suction connections made to a common manifold
provided that the manifold has a cross-sectional area greater than the sum of the individual
pump inlet areas.
Never use a common manifold with a smaller cross-sectional area
NOTE
than the sum of the individual pump inlet areas, as this will significantly
decrease the efficiency of all the pumps used.
Gauges and Meters
It is recommended that a pressure gauge be installed at the pump suction, and a low-
suction pressure alarm be mounted in the suction line. However, do not install any metering
device that causes a flow restriction on the suction piping. For full operating instructions and
guidelines for this equipment, see the documentation provided by the manufacturer.
weatherford.com
Pump and Fluid Systems
Chapter 2: Storage & Installation
9
MP-16 2-Piece 5000 psi January 2013
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