Air operated double diaphragm (AODD) pumps are used in facilities of all sizes, and in a variety of different industries. From petrochemical to food and beverage, these pumps are popular and versatile. Their unique design is ideal for transferring highly abrasive or viscous products. But how do they work?
An AODD pump is a type of positive displacement pump that uses compressed air as a power source. The compressed air is shifted from one chamber to the other by a linked shaft that allows the chambers to move simultaneously. This back-and-forth motion forces liquid out of one chamber and into the discharge piping while the other chamber is being filled with liquid at the same time.
These pumps use reciprocating elastomeric diaphragms and check valves to pump fluid. The liquid chambers are filled and emptied by fluid that is drawn through a common inlet and discharged through a single outlet.
Watch the video below to see a visual explanation:
It is common for ball or flap check valves to be used, depending on the solids passing requirements of the application. These valves operate using the pressure differences in the pumped liquid.
Air operated double diaphragm pumps have good suction lift characteristics and can handle sludges or slurries with a relatively high amount of grit and solid content. AODD pumps are also known to handle highly viscous liquids.
It is important to note that there is usually some pulsation of discharge flow in air operated diaphragm pumps. This pulsating flow can be reduced somewhat by using pulsation dampeners in the discharge piping.