air diaphragm pump
A diaphragm pump (also known as a Membrane pump) is a positive displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or teflon diaphragm and suitable valves on either side of the diaphragm
A double diaphragm is a positive displacement pump which utilises two flexible diaphragms that reciprocate back and forth, creating a temporary chamber, which both draws in and expels fluid through the pump. ... The two diaphragms that are connected by a shaft through the centre section where the air valve is located.
Though it depends upon the pump and application, a positive displacement pump, is generally a self-priming pump. ... For instance, air operated diaphragm pumps self-prime by creating a pressure differential in the diaphragm chamber. This draws in air and pulls the fluid into the suction port.