use of positive displacement pump

Use of Positive Displacement pump

PD pumps captures confined amounts of liquid and transfers it from the suction to the discharge port.

The main reason positive displacement pumps are not more common than dynamic pumps is because they cannot achieve the high flow rates often required for industrial applications.

Flow is constant with changing pressure. A Positive Displacement Pump must not be operated against a closed valve on the discharge side of the pump because it has no shut-off head like centrifugal pumps. A Positive Displacement Pump operating against a closed discharge valve will continue to produce flow until the pressure in the discharge line has increased until the line bursts or the pump is severely damaged - or both. Progressing cavity pumps handling high solids content sludge in a waste treatment plant and reciprocating pumps are applied on coal slurry pipeline with solids contents as high as 40 percent by weight. This is sometimes a surprising PD pump characteristic, but widely varied applications serve as examples.

When low flow rates are adequate or preferred, PD pumps are often a better choice. They are generally more efficient for applications involving moderate to high viscosity fluids, high pressures, or variable system conditions.

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use of positive displacement pump