Valve with increased flow area

Claim 1

A VALVE MECHANISM COMPRISING A VALVE SEAT MEMBER ADAPTED TO BE CONNECTED TO A SOURCE OF FLUID MEDIA TO BE CONTROLLED BY SAID VALVE MECHANISM, AN ANNULAR VALVE MEMBER FOR CONTROLLING THE FLOW THROUGH SAID VALVE SEAT MEMBER, SAID ANNULAR VALVE MEMBER HAVING AN INNER AND AN OUTER PERIPHERY, WITH SAID INNER PERIPHERY DEFINING AN APERTURE THEREIN, SAID VALVE SEAT MEMBER INCLUDING TWO PORTIONS WHICH COOPERATE TO DEFINE AN ANNULAR GROOVE WHICH IS OPEN AT ONE END AND CLOSED AT THE OTHER END AND IS UNOBSTRUCTED FROM SAID CLOSED END TO SAID OPEN END, SAID TWO PORTIONS JOINING TO FORM SAID CLOSED END OF SAID ANNULAR GROOVE, AN ANNULAR SEATING SURFACE ON AN END OF ONE OF SAID TWO PORTIONS EXTENDING ADJACENT THE INNER PERIPHERY OF SAID ANNULAR GROOVE, THE PART OF THE SEAT MEMBER ENCLOSED BY THE ANNULAR SEATING SURFACE ON SAID ONE OF SAID TWO PORTIONS BEING IMPERVIOUS TO FLOW, AN ANNULAR SEATING SURFACE ON AN END OF THE OTHER OF SAID TWO PORTIONS EXTENDING ADJACENT THE OUTER PERIPHERY OF SAID ANNULAR GROOVE, AND A PORT COMMUNICATING WITH SAID ANNULAR GROOVE THROUGH A SIDE WALL THEREOF AND INTERMEDIATE SAID OPEN AND CLOSED ENDS OF SAID ANNULAR GROOVE, SAID VALVE MEMBER ADAPTED TO OVERLIE SAID ANNULAR GROOVE AND SAID ANNULAR SEATING SURFACES, WHEREBY WHEN SAID VALVE MEMBER IS OUT OF ENGAGEMENT WITH SAID SEATING SURFACE SAID FLUID MEDIA FLOWS THROUGH SAID PORT INTO SAID ANNULAR GROOVE AND FROM SAID ANNULAR GROOVE AND AROUND THE OUTER PERIPHERY AND THROUGH SAID APERTURE OF SAID ANNULAR VALVE MEMBER.