The differential pressure across the diaphragm and corresponding internal stresses are low in comparison with similar stresses in mechanically driven diaphragm pumps that use the diaphragm to generate pressure. Discharge pressure capability depends on the compressed air pressure available, up to 300 psi in some models. The advantages are longer diaphragm life and higher discharge pressures. Each style has advantages. Flap valve pumps can pass larger solids, but they may not be as reliable and are not available in certain materials.
Ball valves have better vacuum capability and are available in all materials.
The choice of valve design will depend on the materials pumped and application requirements. The air control mechanism is the functional heart of the AOD pump. It must direct incoming compressed air to the appropriate chamber of the duplex pump while exhausting air from the other chamber. Without centering or failing to shift, the air valve system must operate from full throttle to a stalled condition when the pump is dead-headed. It should function correctly using either dry laboratory compressed air or the wet dirty air found in many plants.