Diaphragm check valve

Claim 1

A VALVE COMPRISING A FIRST BODY PORTION HAVING AN OPENING IN A SURFACE THEREOF AND AN INTERNAL PROTUBERANCE DEFINING A SEAT EXTENDING ACROSS SAID OPENING AND FACING IN THE SAME DIRECTION AS SAID SURFACE, SAID FIRST BODY PORTION FURTHER HAVING INLET AND OUTLET PASSAGES RESPECTIVELY EXTENDING TO AND FROM SAID OPENING AT THE OPPOSITE SIDES OF SAID SEAT, AN ELASTIC MEMBRANE EXTENDING OVER SAID OPENING, A FLEXIBLE DIAPHRAGM SUPERIMPOSED ON SAID ELASTIC MEMBRANE, A SECOND BODY PORTION HAVING A SURFACE MATING WITH SAID SURFACE OF THE FIRST BODY PORTION, MEANS SECURING TOGETHER SAID FIRST AND SECOND BODY PORTIONS WITH THE PERIPHERIES OF SAID MEMBRANE AND DIAPHRAGM CLAMPED BETWEEN THE MATING SURFACE OF SAID BODY PORTIONS, AND CONTROL MEANS CARRIED BY SAID SECOND BODY PORTION AND CONNECTED WITH SAID DIAPHRAGM TO MOVE THE LATTER TOWARD AND AWAY FROM SAID SEAT, SAID ELASTIC MEMBRANE HAVING AN APERTURE THEREIN AT THE SIDE OF SAID SEAT FROM WHICH SAID OUTLET PASSAGE EXTENDS SO THAT, IN THE EVENT THAT FLUID PRESSURE IN SAID OUTLET PASSAGE EXCEEDS THE FLUID PRESSURE IN THE INLET PASSAGE WHEN SAID DIAPHRAGM IS MOVED AWAY FROM SAID SEAT, THE EXCESS PRESSURE URGES FLUID TO ENTER BETWEEN SAID DIAPHRAGM AND MEMBRANE TO URGE THE LATTER INTO SEALING ENGAGEMENT WITH SAID SEAT AND THEREBY PREVENT BACK-FLOW THROUGH THE VALVE.