Patent ID: 8226381

Claim:
A double-diaphragm pump for pumping a fluid to be pumped from reservoir to a receptacle, the pump comprising: first and second working chambers; a diaphragm in each of the working chambers and dividing each working chamber into a pumping chamber and a motive fluid chamber; a shaft interconnecting the diaphragms for synchronized reciprocating movement; a valve alternatingly placing one of the motive fluid chambers in communication with a source of pressurized motive fluid while placing the other motive fluid chamber in communication with an exhaust assembly; an inlet manifold communicating with the pumping chambers and adapted to communicate with the reservoir; an outlet manifold communicating with the pumping chambers and adapted to communicate with the receptacle; a check valve assembly operatively positioned between each pumping chamber and each of the inlet and outlet manifolds, each check valve assembly including a first conduit having a first flange, a second conduit having a second flange abutting against the first flange, a stopper, and a valve body, wherein the valve body includes a circumferential notch that divides the body into first and second portions between the notch and respective first and second opposite ends of the body; and an o-ring around the first portion of the valve body; wherein the valve body includes a body bore extending through the valve body between the first and second ends, the body bore defining a circular opening in the second end of the body, the body bore communicating between the first and second conduits; wherein the notch substantially insulates the circular opening from distortion arising from securing the valve body between the first and second flanges; wherein the stopper seats against the circular opening to prevent fluid flow through the body bore from the second end to the first end, and unseats from the circular opening to permit fluid flow through the body bore from the first end to the second end; wherein the first portion of the valve body includes a tapered surface that is of smaller diameter at the first end of the valve body and increases in diameter to the notch; and wherein securing the valve body between the first and second flanges forces the tapered surface into the o-ring and energizes the o-ring to fluid-tightly seal between the valve body and the first and second flanges.