Air operated double diaphragm pumps are air-powered, reciprocating
positive displacement pumps with two pumping chambers. Two
diaphragms, centrally located in the chambers, separate the compressed
air (dry side) from the fluid being pumped (wet side). A shaft transmits the
reciprocating motion of one diaphragm to the other. A valve (air motor)
alternatively distributes the air from one chamber to the other; thus a
reciprocating movement of the diaphragms is created. With each stroke fluid is
discharged by one of the diaphragms whilst the opposite diaphragms sucks new
fluid into the expanding chamber. Check valves, two on the discharge side and
two on the suction side, control and direct the fluid flow.