An Introduction to Air Operated Double Diaphragm Pumps

Air operated double diaphragm pumps are powered by compressed air, nitrogen or natural gas. The main directional (pneumatic) control valve distributes compressed air to the gas chamber, applying uniform pressure to the inner surface of the diaphragm.

Air operated double diaphragm pumps

How air operated double diaphragm pumps works?

At the same time, the discharged gas is discharged from the rear of the other side of the pump through the guide port of the gas valve assembly. When the gas pressure in the inner chamber of the diaphragm pump exceeds the pressure in the liquid chamber, the diaphragm connecting rod moves back and forth, discharging on one side and inhaling on the other side.

The direction of discharge and suction of liquid is controlled by the direction of the check valve (ball or flap valve). The suction stroke causes the pump to perform suction. The suction stroke reduces chamber pressure and increases chamber volume. This creates an atmospheric pressure differential that pushes the liquid through the suction pipe, through the suction side check valve, and into the external liquid chamber. Suction side stroke also initiates the reciprocating (displacement, stroke or cycle) movement of the pump.

The air operated double-diaphragm pump mechanically pulls the suction diaphragm through the stroke. The inner plate of the pump contacts with the aligned driving plunger, moving the guide valve core. After the pilot valve is activated, a pressure signal is sent to the other end of the main directional air valve, and the pump changes the direction of the compressed air to the other side of the internal chamber.

Air operated double diaphragm pumps
AODD pump How it works?