This is a high speed impeller in the pump to transfer energy to the liquid, liquid transport machinery. Belong to this type of pump has various forms of centrifugal pump, mixed flow pump, axial flow pump and vortex pump.

It is the use of pump studio (pump shell or cylinder) volume for periodic changes to transport liquid, the discharge process is intermittent. This kind of pump is also known as positive displacement pump, which can be divided into reciprocating pump and rotary pump two kinds.

It relies on the energy of another working fluid to pump or pressure the liquid (i.e. relying on the static pressure energy or kinetic energy of the fluid to transport the liquid)