How AODDP (Air Operated Double Diaphragm Pumps) work.

The working principle of air operated diaphragm pumps is really very simple.

Hopefully, we will answer the question “How does a diaphragm pump work?”

Fluimac air diaphragm pumps are driven by compressed air. Air enters the air valve which will allow pressurized pneumatic air into one of the two chambers.

As the air enters and fills the chamber on the left the flexible diaphragm expands and compresses the fluid on that side of the diaphragm. This effectively forces the upper valve to open, releasing the fluid into the discharge pipe system. We call this the “discharge chamber” at this point of the pumping cycle.

At the same time, the discharge chamber is pumping liquid out of the pump, the opposite diaphragm is pulled in toward the center housing by the drive shaft.

Negative pressure is generated in that fluid chamber lifting the lower valve which draws fluid into this chamber, this is the “suction chamber” at this point of the pumping cycle.

As soon as this “suction chamber” diaphragm makes contact, the air pilot pin is forced across the center housing, air exhausts to atmosphere from the discharge chamber, at the same time compressed air enters the “suction chamber” and the pumping action is reversed. The vacuum side becomes the pressure side and vis versa.

This action results in the familiar “CHUF-CHAF” as the pump switches between compression and exhaust cycles, first delivering from one side and then the other.

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(By Samtar (Own work) [CC BY-SA 4.0 (], via Wikimedia Commons)