Check valve assembly

Claim 1

IN A HOUSING HAVING A VALVE SEAT BETWEEN AN OUTLET AND AN INTERIOR PORTION OF SAID HOUSING, MEANS FOR CONTROLLING PRESSURE FLUID FLOW BETWEEN SAID HOUSING INTERIOR PORTION AND OUTLET COMPRISING A RESILIENT ANNULAR MEMBER SEALABLY ENGAGED WITH SAID VALVE SEAT, A RIGID MEMBER HAVING AN ANNULAR SEALING SURFACE ADJACENT TO THE PERIPHERAL EDGE THEREOF AND NORMALLY SEALABLY ENGAGED WITH SAID ANNULAR MEMBER, DIAPHRAGM MEANS INTEGRAL WITH SAID ANNULAR MEMBER, PASSAGE MEANS BETWEEN SAID DIAPHRAGM MEANS AND ANNULAR MEMBER IN OPEN PRESSURE FLUID COMMUNICATION WITH SAID OUTLET, APERTURE MEANS IN SAID RIGID MEMBER THROUGH WHICH THE FLOW PASSES, ANOTHER SEALING SURFACE ON SAID RIGID MEMBER ABOUT SAID APERTURE MEANS FOR ENGAGEMENT WITH SAID DIAPHRAGM MEANS, SAID DIAPHRAGM MEANS BEING DISENGAGED FROM SAID OTHER SEALING SURFACE IN RESPONSE TO THE FLOW TO PROVIDE PASSAGE THROUGH SAID APERTURE MEANS IN ONE DIRECTION AND BEING ENGAGED WITH SAID OTHER SEALING SURFACE IN RESPONSE TO THE FLOW TO PREVENT PASSAGE THROUGH SAID APERTURE MEANS IN THE OPPOSITE DIRECTION, AND SAID RIGID MEMBER HAVING AN EFFECTIVE AREA BETWEEN SAID SEALING SURFACES AND BEING MOVABLE IN RESPONSE TO THE FLOW ACTING ON SAID EFFECTIVE AREA TO DISENGAGE SAID FIRST NAMED SEALING SURFACE FROM SAID ANNULAR BODY AND PROVIDE PASSAGE THEREBETWEEN IN THE OPPOSITE DIRECTION.