Pulsating effect on pipelines.
Rotary pumps are positive displacement pumps in which the main pumping action is caused by rotating
gears. As the gears rotate, the fluid is trapped between their teeth and is carried around to the discharge
outlet. There are a variety of rotary pumps. In petroleum handling operations, their principal application is in
low pressure, low capacity operations. The advantage of rotary pumps is their ability to pull fluid into the
housing without the aid of a priming tank or vacuum pump (self-priming). They also have constant discharge
characteristics. The only petroleum vehicle that presently uses rotary motion is the M49A2C.
Centrifugal pumps employ centrifugal force as the principle of operation. Simply put, the action of this
pump is an impeller rotating in a volute casing. Fluid forced into the eye of the impeller is picked up by the
vanes and discharged into the casing by centrifugal force. Because of their simplicity and low cost and
ability to operate under a wide variety of conditions, centrifugal pumps are one of the most popular types.
Centrifugal pumps that are in use in the petroleum pipeline and TPT operations include:
The 600-GPM hose line pump which is a 6-inch, single stage, self-priming pump, diesel-engine-driven,
wheel-mounted, air-cooled, centrifugal pump.
The 1,250-GPM flood and transfer pump is a 6-inch, single-stage, skid-mounted, diesel-engine-driven,
self-priming centrifugal pump.
The 800-GPM mainline pump is a skid-mounted, diesel-engine-driven, three stage centrifugal pump.
Centrifugal pumps can be classified or described by:
Size of the suction and discharge ports.
Number of impellers or stages.
Whether they are self priming or must be force fed.
Six inch, single stage, self priming pump.
Centrifugal pumps are used to transfer fuel from storage tanks to truck loading racks, from one tank to
another, and to feed pump stations on the main pipeline.
Six inch, two stages: Used on six, eight, and ten inch pipelines as booster pumps. May be used in
parallel at ocean terminals to off load tankers.
Four inch, four stage: Used on four and six inch pipelines as booster pumps.
Six inch, three stage, diesel engine driven: Used on six, eight, and ten inch pipelines as booster pumps.
This pump will replace the four-inch, four stage and the six inch, two stage pump in the Army system.
3-3
QM 5094
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