A diaphragm pump (also referred to as a Membrane pump) is a positive displacement pump that uses a combination of the reciprocating actions of a rubber, thermoplastic or teflon diaphragm and suitable valves on either side of the diaphragm

A dual diaphragm is a positive displacement pump which utilises two flexible diaphragms that reciprocate backwards and forwards, creating a temporary chamber, which both allures and expels fluid through the pump. … Both diaphragms that are linked by a shaft through the centre section where the air valve is situated.

Though it depends upon the pump and application, a positive displacement pump, is generally a self-priming pump. … For instance, air operated diaphragm pumps Air Diaphragm Pump self-primary by creating a pressure differential in the diaphragm chamber. This allures surroundings and pulls the liquid into the suction port.