Air driven diaphragm pump

Abstract

A pump having a center section including an actuator housing and an air valve is arranged with air chambers to either side of the actuator housing. Diaphragms are associated with the air chambers to create enclosed cavities for alternately pressurizing and venting the diaphragms. The actuator uses a pilot shifting shaft which is shuttled by movement of the diaphragms. An air valve is controlled by the shuttle shifting shaft to control flow to and from the air chambers. The passageways from the air chambers to exhaust find the passage to the outlet being at least as restrictive to air flow as the remainder of the passageways so as to prevent major pressure decreases within the actuator body. A diffuser includes a thin space between two surfaces into which the exhaust is directed. One of the surfaces is associated with a porous block of material. Exhausting air is distributed within the space and then passed through the porous block of material. The cylindrical orifice through which flow radially passes is roughly the same cross section as the restricted exhaust passageway. The air valve includes a cylinder closed at one end with an end cap positioned at the other end. The end cap is arranged with a plug that fits within the cylinder so as to seal without close tolerance on axial positioning. Bolts retaining the air valve and the actuator housing also retain the end cap as well.