A double diaphragm pump is a positive displacement pump which utilises two flexible diaphragms that reciprocate back and forth, creating a temporary chamber, which both draws in and expels fluid through the pump. The diaphragms work as a separation wall between the air and the liquid. This pump is sometimes referred to as a membrane pump. Diaphragm pumps are self priming and are ideal for viscous liquids.

Dry running is a one of the key features that differentiate Air Operated Diaphragm pumps from other types of pumps. In majority of the cases this will not damage the pump, nor its elements. This is why, AODD pumps are often used in applications in which the fluid may unexpectedly run out (sumps dewatering, tanks and cisterns transfers, etc.).

However, we should be aware of the few side effects resulting from dry running of the pump and costs and risks associated with it.

When running dry the Diaphragm Pump will not overheat - there are no surfaces which will rub with one another causing excess heat generation. Also, AODD pump suction cavitation is not as destructive as in case of rotary pumps. However, it is not recommended to run dry constantly or for long periods.

Dry running is unproductive and expensive. Diaphragm pump which run dry speed up. A dry running pump can operate two to three times faster than it does when under load. This will result in bigger air consumption (electricity cost), and unproductive consumption of diaphragms cycles. Due to increased pump speed during run dry operation diaphragms will make a lot of "empty" strokes decreasing own elasticity (ability to return to its original shape after it has been stretched) what result in shorten lifetime.