Top entry ball valve

Claim 1

A TOP ENTRY BALL VALVE HAVING A FLOW PASSAGE AND BEING ADAPTED TO BE SECURED IN A FLUID LINE TO PERMIT REGULATED FLUID FLOW THERETHROUGH COMPRISING A VALVE BODY HAVING COAXIALLY ALIGNED AND AXIALLY SPACED APART ANNULAR SHOULDERS FORMED CIRCUMJACENT THE VALVE PASSAGE, EACH SAID SHOULDER HAVING A RADIALLY EXTENDING FLAT SURFACE FACING INWARDLY; A CAP REMOVABLY SECURED TO THE VALVE BODY PROVIDING ACCESS TO THE INTERIOR THEREOF MIDWAY BETWEEN SAID FLAT SURFACES; AN ANNULAR VALVE SEAT FORMED OF A FLEXIBLE BUT RELATIVELY INCOMPRESSIBLE MATERIAL REMOVABLY FITTED WITHIN EACH SHOULDER AND HAVING A FRUSTOCONICAL SURFACE FACING SAID FLAT SURFACE AND DEFINING THEREWITH A SPACE FOR RELATIVE AXIAL MOVEMENT OF SAID VALVE SEAT; AN ANNULAR SPRING MEMBER HAVING A FRUSTOCONICAL SURFACE IN MATING ENGAGEMENT WITH THE FRUSTOCONICAL SURFACE OF EACH SAID VALVE SEAT; AND A ROTATABLE SPHERICAL VALVE MEMBER REMOVABLY DISPOSED WITHIN SAID VALVE BODY AND HAVINGA BORE THERETHROUGH COAXIALLY ALIGNED WITH SAID VALVE SEATS IN A FULL FLOW OPEN POSITION, SAID SPHERICAL VALVE MEMBER HAVING A LONGITUDINAL DIMENSION THROUGH THE BORE NOT GREATER THAN THE DISTANCE BETWEEN THE OPPOSED VALVE SEATING SURFACES WITH THE SEATS IN AN INSTALLED POSITION AND HAVING A LATERAL DIMENSION EXCEEDING SUCH DISTANCE WHEREBY UPON ROTATION OF THE SPHERICAL VALVE MEMBER FROM THE FULL FLOW OPEN POSITION THE FRUSTOCONICAL SURFACE OF EACH VALVE SEAT IS CAMMED AXIALLY OUTWARDLY AGAINST THE BIASING FORCE OF SAID SPRING MEMBERS.