Displacement Pumps

Displacement pumps represent a large category of pumps in which a fixed volume of the pumped liquid is delivered every revolution of the pump shaft. Displacement pumps are categorized under reciprocating or rotary pumps, depending on the motion of the moving element within the pump. Reciprocating pumps are classified into piston, plunger, and diaphragm pumps that can be either single- or double-acting. The rotary pumps are also classified as having single or multiple rotors with each category having its sub-classification. When reciprocating pumps are used in a pumping system, the flow rate is controlled either by controlling the driver speed or by changing the length of stroke, in some designs. In rotary pumps, the fluid is displaced by rotating element(s) of different geometries inside the pump. The motion of these elements creates low pressure on one side and supplies the fluid against the high pressure on the other side.