Positive Displacement Pump

Positive Displacement Pump

A positive displacement (PD) pump moves a fluid by repeatedly enclosing a fixed volume and moving it mechanically through the system. Its internal design protects and prevents fluid from flowing back into the pump inlet or its housing. PD pumps can be either rotary or positive displacement. The pumping action is cyclic and can be driven by pistons, screws, gears, rollers, diaphragms or vanes.

These pumps can handle higher viscosity fluids such as oil, paints, resins or foodstuffs and operate at high pressures and relatively low flows more efficiently. Operational volumetric efficiency increases with increasing viscosity and mechanical efficiency increases with increasing dischargepressure.