Patent ID: 7213611

Claim:
A valve assembly, comprising: a body including a bore and a longitudinal axis; a valve received within the bore and configured for axial movement between an open position in which fluid flow through the body is permitted and a closed position in which fluid flow through the body is prevented; first and second sealing members secured for movement with the valve and positioned between the valve and the body such that an internal fluid pressure within the bore is applied to a first side of the first and second sealing members and a common reference pressure is applied to a second side of the first and second sealing members, a first surface area portion of the bore adjacent the first sealing member is greater than a second surface area portion of the bore adjacent second sealing member such that an axial force imparted on the valve adjacent the second sealing member is less than an axial force imparted on the valve adjacent the first sealing member; a resiliently compressible member positioned to bias the valve toward the open position; and wherein the valve is normally in the open position and is configured to move directly to the closed position such that the valve will not return to the open position from an intermediate travel position when the internal fluid pressure exceeds a predetermined pressure, and wherein the valve is adapted to return from the closed position to the open position when the internal fluid pressure is less than the predetermined pressure.