Air Operated Double Diaphragm (AODD) pumps utilize a different type of pumping mechanism when compared to standard, more widely used centrifugal pumps. A centrifugal pump utilizes a mechanically rotating impeller, which is often powered by a separate motor, to shift fluids. An AODD pump,on the other hand, leverages air pressure pushed through an array of air valves to move diaphragms in order to create a suction and discharge pressure. The AODD pump is a self-contained unit, necessitating nothing more than a compressed air line to operate.

Suction and discharge valves are put together into the AODD pump system to impede backflow on the suction cycle and to allow pressure on the discharge cycle.  These valves can either be of the ball check/seat variety or the flap check/seat style. Normally, the particular type of valves used in an AODD pump system is identified when the pump is being designed by describing the percentage of solids that will be pumped.

When compressed air penetrates the main air valve of the AODD pump, it is pushed through additional pilot valves and a spool and sleeve system so that it can exist on both sides of the pump. When one side is pressurized, the diaphragm shifts inside the container in one direction. This diaphragm is connected to a diaphragm rod, which is then fitted to a second diaphragm on the other side of the pump. The second diaphragm is pulled toward the first diaphragm, creating suction in the other chamber.

As the diaphragms complete their move toward one side of the pump, they come in contact with an actuator, which conveys a message to the pilot valve that it should push air into the other side of the pump. The air entering the first side of the pump then moves the second diaphragm in the opposite direction, and the process is repeated as reported above. This entire process is named a “cycle.”  Depending on the pump size and air pressure, an AODD pump can cycle several times per second. This creates an uninterrupted stream of discharge liquid.

The internal pieces of an AODD pump that come into contact with the pumping media can be supplied in a extensivegroupof compounds to settle chemical compatibility problems.  These pieces can also be exchanged with others to provide adaptability when changing pumping applications.  There is almost no limit to the media that can be pumped if the right material components are chosen.

AODD pumps are utilized mostly where there is limited space and accessibility.  They are also used in places where there is no electrical power available. Recently, AODD pumps have been invented and approved for use on gas well applications, where they can be powered by sweet and sour natural gas.