Check valve clapper construction

Claim 1

IN A CHECK VALVE HAVING A CASING WITH AN INLET SEALING SEAT, A CLAPPER CONSTRUCTION COMPRISING: (A) A DISC SHAPED CLAPPER MEMBER CONTAINING TWO SIDES AND A CIRCULAR PERIPHERAL PORTION, (1) ONE OF SAID SIDES HAVING A SUBSTANTIALLY FLAT SEATING FACE FOR SEALING SAID INLET, SEAT, (2) THE OTHER OF SAID SIDES HAVING RAISED MEANS UNIFORMLY SPACED INWARDLY FROM SAID PERIPHERAL PORTION OF SAID CLAPPER MEMBER DEFINING A CIRCULAR MARGINAL PORTION BETWEEN SAID PERIPHERAL AND SAID RAISED MEANS, (B) AN ELASTOMER DIAPHRAGM COMPRISING A SUBSTANTIALLY FLAT IMPERFORATE PORTION COVERING SAID CLAPPER FLAT SEATING FACE, (1) SAID DIAPHRAGM HAVING A CIRCULAR LIP INTEGRAL WITH THE PERIPHERY OF THE SUBSTANTIALLY FLAT IMPERFORATE PORTION AND SPACED FROM SAID SUBSTANTIALLY FLAT IMPERFORATE PORTION A SUFFICIENT DISTANCE TO SNUGLY ENGAGE SAID MARGINAL PORTION OF SAID CLAPPER MEMBER, AND TERMINATING IN AN INTERIORLY ORIENTED EDGE ADJACENT SAID RAISED MEANS, (2) SAID DIAPHRAGM BEING MOUNTED UPON SAID CLAPPER MEMBER WITH A SLIGHT DEFORMATION THEREBY BEING RETAINED SOLELY BY THE INHERENT ELASTICITY OF SAID DIAPHRAGM, (3) SAID RAISED MEANS EXTENDING ABOVE SAID CLAPPER MEANS A DISTANCE GREATER THAN THE THICKNESS OF SAID DIAPHRAGM, (C) MEANS JOINED TO SAID CLAPPER MEMBER FOR HINGEDLY CONNECTING SAID CLAPPER MEMBER TO SAID CASING.