A double diaphragm(AODD Pump) is a positive displacement pump which utilises two flexible diaphragms that reciprocate back and forth, creating a temporary chamber. The flexible diaphragms both draws in and expels fluid through the pump. The diaphragms work as a separation wall between the air and the liquid.

The first stroke

The two diaphragms that are connected by a shaft through the centre section where the air valve is located. The purpose of the air valve is to direct the compressed air to the back of diaphragm number one causing it to move away from the centre section. The number one diaphragm causes a press stroke moving liquid out of the pump. At the same time diaphragm number two is performing a suction stroke. The air behind diaphragm number two is being pushed out to the atmosphere causing atmospheric pressure to push the liquid to the suction side. The suction ball valve is pushed away off its seat allowing the fluid to flow past the ball valve into the liquid chamber.

The second stroke

When the pressurised diaphragm number one has reached the end of its stroke, the movement of the air is switched from diaphragm number one to the back of diaphragm number two by the air valve. The compressed air pushes diaphragm number two away from the centre block resulting in diaphragm number one being pulled toward the centre block. In pump chamber number two the discharge ball valve is pushed off its seat, whilst in pump chamber number one the opposite occurs. Upon completion of the stroke the air valve leads the air again to the back of diaphragm number one and restarts the cycle.

Membrane Pumps are used in many industries. Providing the site has a compressed air supply, you have a robust pump ready to run. About Your Application , Please contact with DEFU diaphragm Pump and one of our pump experts will contact you!