Air pressure actuated single-acting diaphragm pump

Claim 1

A single acting diaphragm pump system which comprises a pump housing, a diaphragm dividing the housing into a pumping chamber having means for pump intake and pump discharge, and a pump actuating chamber having an opening opposite to, and concentric with the diaphragm, said actuating chamber having a supply- and vent connection for introducing into said pump actuating chamber a fluid pressure medium effective to move the diaphragm to execute the delivery stroke of the pump, as well as for venting said actuating chamber during the return suction stroke of the pump, a pump actuating self-contained power cylinder unit detachably mounted upon said pump housing concentric with said opening in the pump housing, and comprising a cylindrical body portion, a top plate having a vent opening, a bottom plate provided with a central bottom opening, a piston having a piston rod extending through said bottom opening, said bottom plate having formed therein a flow passage communicating with the interior of the cylinder, for admission of pressure fluid during the pump delivery stroke, and for venting during the pump return suction stroke, a sealing device connected to said bottom plate, to provide sealing relationship between the piston rod and said bottom plate, a set of external bolt connections between said top plate and said bottom plate, whereby said cylindrical portion is endwise compressed between said plates, and a set of anchoring studs for detachably mounting said power cylinder unit on said pump housing, and a control system which comprises a first three-way control valve unit having a valve housing provided with communicating connections extending respectively to a supply of said fluid pressure medium, to said auxiliary actuating means and to the atmosphere, and having a first valve member shiftable in said housing, said valve member, said housing and said communicating connections being so constructed and arranged relative to one another that shifting the valve member in one direction will condition the valve unit for admitting said fluid pressure medium to said auxiliary fluid pressure actuated means to execute the pump filling stroke, and shifting of the valve member in the opposite direction will condition the valve unit for venting said auxiliary means during the delivery stroke, a second three-way control valve unit having a valve housing with communicating connections respectively to a supply of fluid pressure medium and to said actuating chamber and to the atmosphere, and having a second valve member, said valve member and said housing and said communicating connections being so constructed and arranged relatiVe to one another, that shifting the valve member in one direction will condition the valve unit for admitting said fluid pressure medium to said actuating chamber to execute the pumping stroke, and shifting the valve member in the opposite direction will condition the valve unit for venting said actuating chamber during the pump filling stroke, and a pilot valve cooperatively associated with said first and second control valves, and constructed and arranged so as to be operable to cause the first control valve member to shift in said one direction while causing the second control valve member to shift in said other direction, for executing the delivery stroke, and to cause reversal of the movements of said first and second control valve members for executing the return stroke of the pumping cycle, and an outward extension member for said piston rod provided with means for engaging said pilot control valve in a manner to operate said first and second control valve units, for maintaining the operating cycle of the pump.