Working principle of pneumatic double diaphragm pump

Pneumatic diaphragm pumps use compressed air, nitrogen or natural gas as power. The main directional (pneumatic) control valve distributes compressed air to the gas chamber, applying uniform pressure on the inner surface of the diaphragm. At the same time, the discharged gas is discharged from the back of the other side of the pump through the guide port of the gas valve assembly. The gas pressure in the inner cavity of the pneumatic double diaphragm pump exceeds the pressure in the liquid cavity, and the diaphragm connecting rod moves back and forth, discharging on one side and sucking on the other side. The direction of discharge and suction of liquid is controlled by the direction of the check valve (ball valve or sheet valve). The suction stroke causes the pump to perform suction. The suction stroke can reduce the pressure of the chamber and increase the volume of the chamber. Thus, the atmospheric pressure difference is generated, which pushes the liquid through the suction pipe, through the suction side check valve, and flows into the external liquid cavity. The suction side stroke can also start the reciprocating (displacement, stroke or circulation) movement of the pump. The pneumatic double-diaphragm pump pulls the suction diaphragm through the stroke mechanism. The inner plate of the pneumatic double-diaphragm pump comes into contact with the aligned driving plunger and moves the guide spool. After the pilot valve is activated, it sends a pressure signal to the other end of the main directional air valve, and the pneumatic double diaphragm pump changes the direction of the compressed air to the other side of the internal chamber. This repeated movement completes the continuous delivery of the medium.