About the working principle of Wilden AODD pump

    Wilden® AODD pumps are classified as reciprocating,  positive-displacement-style pumps. The pump operates by  displacing fluid from one of its two liquid chambers upon  each stroke completion. To operate correctly, AODD pumps  require a precise amount of pressure (measured in pounds  per square inch) and air (measured in cubic feet per minute)  to deliver the proper amount of fluid.

    The simple genius of the Wilden AODD pump design means  that there are only a few wetted parts that are dynamic: the  two diaphragms, which are connected by a common shaft,  the two inlet valve balls and the two outlet valve balls. The  diaphragms act as a separation membrane between the  compressed air supply and the liquid. Driving the  diaphragms with compressed air instead of the shaft  balances the load on the diaphragm, which removes  mechanical stress from the operation and extends  diaphragm life. This also allows the valve balls to open and  close on the valve seats, which direct liquid flow. This  simple design and operation makes it easy for the operator  to find the correct pressures and flows to optimize  its operation.

    More specifically, the pump begins operation when the air  distribution system directs the air supply to the right air  chamber and back side of the diaphragm (See Figure 1). This  moves the diaphragm away from the center block and  toward the liquid chamber, in the process pulling the  opposite diaphragm inward. This means the opposite  diaphragm is now on its suction stroke. At the same time,  atmospheric pressure forces fluid into the inlet manifold,  forcing the inlet valve ball off its seat. This allows liquid to  move past the inlet valve ball and into the liquid chamber.

    When the pressurized right liquid chamber reaches its liquid  capacity, the air valve redirects compressed air to the back  side of the opposite diaphragm. This forces that diaphragm  away from the center block while pulling the right  diaphragm toward the center block. This closes the inlet  valve ball on the opposite side while lifting the discharge  valve ball off its seat and forcing the liquid to flow through  the discharge manifold. The process is repeated for the  opposite side, with the liquid chamber filling, the forced air  redirecting the diaphragms and the created pressure forcing  the discharge valve ball off its seat as the liquid moves  through the discharge manifold.

    As the pump reaches its original starting point, each  diaphragm has gone through one suction and one discharge  stroke, which constitutes one pumping cycle.