Ball valve seat

Claim 1

IN A BALL VALVE CONSTRUCTION HAVING OPPOSED VALVE SEATS SURROUNDING AN INLET OPENING WITH SEALING RING ACCOMMODATING GROOVES HAVING AT LEAST TWO TRANSVERSELY OPPOSED SUBSTANTIALLY FLAT SEATING SURFACES AND A CONNECTING SURFACE, A SEALING RING RECEIVED IN SAID ACCOMMODATING GROOVES, A VALVE MEMBER BEING AT LEAST PARTIALLY SPHERICAL AND HAVING ROUNDED SEALING RING CONTACTING SURFACES AND ADAPTED FOR ROTATION SEALING RING CONTACTING SURTHE IMPROVEMENT COMPRISING SAID SEALING RING COMPRISING AN ANNULAR BODY OF RESILIENT MATERIAL HAVING (A) AN EXTERIOR PORTION, AND (B) AN INTERIOR PORTION, THE LATTER DEFINING A FLUID-COMMUNICATING PASSAGE, SAID EXTERIOR PORTION HAVING, IN CROSS-SECTION, A FIRST SUBSTANTIALLY FLAT PERIPHERAL SHOULDER FACING SUBSTANTIALLY TRANSVERSELY OF THE FLUID PASSAGE AND SAID EXTERIOR PORTION HAVING A FURTHER SUBSTANTIALLY FLAT PERIPHERAL SHOULDER DISPOSED TRANSVERSELY OF SAID FIRST PERIPHERAL SHOULDER IN SPACED RELATIONSHIP THEREWITH, SAID SHOULDERS BEING ADAPTED TO MEET IN SEALING CONTACT THE SAID TRANSVERSELY OPPOSED SEATING SURFACES OF SAID SEALING RING ACCOMMODATING GROOVES, SAID ANNULAR BODY HAVING A SUBSTANTIALLY CONVEX SURFACE EXTENDING BETWEEN SAID SHOULDERS FOR ENGAGEMENT BY SAID ROUNDED SEALING RING CONTACTING SURFACES OF SAID VALVE MEMBER, AND A SUBSTANTIALLY CONCAVE SURFACE SPACED FROM SAID CONNECTING SURFACE AND OPPOSED TO SAID SUBSTANTIALLY CONVEX SURFACE AND DISPOSED BETWEEN SAID SHOULDERS WHEREBY PRESSURE APPLIED TO SAID SUBSTANTIALLY CONVEX SURFACE BY ENGAGEMENT WITH SAID ROUNDED SEALING RING CONTACTING SURFACES OF SAID VALVE MEMBER FLEXES SAID SUBSTANTIALLY CONVEX SURFACE OUTWARDLY TO CONFORM AT LEAST IN PART TO SAID ROUNDED SEALING RING CONTACTING SURFACES OF SAID VALVE MEMBER THEREBY ESTABLISHING SEATING CONTACT AND MAINTAINING THE DESIRED SEALING CONTACTS BETWEEN SAID SEALING RING AND THE CORRESPONDING SEATING SURFACES OF SAID SEALING RING ACCOMMODATING GROOVES.