Air Operated Double Diaphragm Pump Technology

The basic configuration of an Almatec® air-operated double-diaphragm (AODD) pump consists of two external side housings with a center housing between them. Each of the side housings contain a product chamber separated from the center housing by a diaphragm, which are interconnected by a piston rod. Governed by an air control system, the diaphragms are alternately subjected to compressed air so that they move back and forth.

In the first figure, compressed air has forced the diaphragm on the left side of the pump towards the product chamber and displaced the liquid from that chamber through the open valve at the top of the discharge port. Liquid is simultaneously drawn in by the diaphragm on the right, thus refilling the second product chamber. When the end of the stroke is reached, it reverses automatically and the cycle is repeated in the opposite direction.

In the second figure, liquid is drawn in by the diaphragm on the left and displaced by the diaphragm on the right. The liquid is displaced and, thus, conveyed by the compressed air. The diaphragms merely serve as barriers and are not pressurized. This is a fact of decisive importance for the service life of the diaphragms.