How QBY Pneumatic Diaphragm Pump Works – Complete Guide to AODD Pump Operation

The QBY air-operated double diaphragm pump operates on a simple yet highly effective principle. Two flexible diaphragms are connected by a common shaft, forming two symmetrical working chambers. Compressed air enters the air distribution valve and pushes the diaphragms in one direction, while simultaneously exhausting air from the opposite chamber. When the stroke reaches its end, the air distribution mechanism automatically redirects compressed air to the other chamber, reversing the diaphragm movement.
This creates a continuous synchronized reciprocating motion. Each working chamber is equipped with two one-way ball valves. As the diaphragm moves, the volume inside the chamber changes, causing the inlet and outlet ball valves to alternate between opening and closing. This action draws liquid into the chamber on the suction stroke and discharges it on the pressure stroke, resulting in a steady, pulsating flow.
The QBY pump’s air distribution system is designed for reliability and efficiency. The fifth-generation QBY5 series features a three-way pilot-operated air valve that eliminates dead points and prevents pump stalling. The pump can be started and stopped simply by opening or closing the air supply valve, and the flow rate can be infinitely adjusted by regulating the air pressure or installing a throttling valve at the outlet. No complex electrical controls, cables, or fuses are needed.