Reciprocating pumps (also oscillating pumps) are a group within the positive displacement pumps where the volume of the pump chamber is periodically changed by an axial movement of the inner part (piston).
By asynchronously opening and closing the inlet respective outlet of the pump chamber, the fluid will moved in the pump chamber and then pressed to the discharge side.
Reciprocating pumps are generally used for applications that require relatively low flows and high pressures. Since each cylinder delivers a definite volume of liquid to the system, these pumps are also applicable for dosing and metering tasks. The disadvantage against rotating pumps is the pulsating operation.
Positive Displacement Pump