Ball valve seat construction

Claim 1

A ROTATABLE SPHERICAL PLUG VALVE COMPRISED OF A VALVE BODY HAVING A BORE EXTENDING THERETHROUGH; A SPHERICAL VALVE MEMBER POSITIONED IN THE BORE, SAID SPHERICAL PLUG MEMBER HAVING A PORT THE AXIS OF WHICH IS ALIGNABLE WITH THE AXIS OF THE BORE IN THE OPEN POSITION OF THE VALVE; AN APERTURE IN THE VALVE BODY; A STEM HAVING AN INNER END ENGAGED WITH THE VALVE MEMBER AND AN AXIAL OUTER END WHICH EXENDS THROUGH SAID APERTURE IN THE BODY; MEANS FORMING A SEAL BETWEEN SAID APERTURE AND SAID STEM; END MEMBERS EXTENDING INTO EACH END OF THE BODY BORE, EACH END MEMBER HAVING MEANS WHICH LIMITS ENTRY OF THE END MEMBER INTO THE BODY TO A PREDETERMINED AMOUNT, EACH END MEMBER HAVING A PASSAGE WITH WHICH THE PORT IN THE VALVE MEMBER CAN BE ALIGNED TO FORM THE RUN OF THE VALVE AND AN AXIAL INNER END HAVING A PORTION TAPERINGLY DIVERGING AXIALLY INWARDLY FROM THE PASSAGE, AN ANNULAR GROOVE IN THE TAPERINGLY DIVERGING PORTION OF THE AXIAL INNER END, THE INNER CIRCUMFERENTIAL WALL OF SAID GROOVE SPACED FROM THE PASSAGE PROVDING A WALL BETWEEN THE PASSAGE AND GROOVE, AN ANNULAR SEAT MEMBER POSITIONED IN EACH OF SAID GROOVES, THE DEPTH OF EACH OF SAID SEAT MEMBERS IN ITS RESPECTIVE GROOVE BEING SUFFICIENT SO THAT SUFFICIENT FRICTION IS DEVELOPED BETWEEN THE SEAT MEMBERS AND THEIR GROOVES TO RETAIN THE SEAT MEMBERS WITHIN THEIR GROOVES FOR A PREDETERMINED VELOCITY OF FLOW WHEN THE VALVE IS IN A POSITION OTHER THAN CLOSED, EACH SEAT MEMBER HAVING A PORTION EXTENDING BEYOND THE SURFACE OF SAID TAPERINGLY DIVERGING PORTION TERMINATING IN A TAPERED SURFACE TO OPPOSE THE SPHERICAL SURFACE OF THE VALVE MEMBER, EACH END MEMBER EXTENDING INTO THE BODY BORE AN AMOUNT SUFFICIENT TO FORCE THE SEAT MEMBER INTO INTIMATE SEALING CONTACT WITH THE SPHERICAL SURFACE OF THE VALVE MEMBER, THE INWARD MOVEMENT OF THE END MEMBERS ARRESTED BY THE MENS LIMITING ENTRY SOL THAT THE INTERFERENCE BETWEEN THE VALVE MEMBER AND SEATS IS A PREDETERMINED FIXED AMOUNT; MEANS DISENGAGEABLY CONNECTING SAID END MEMBERS TO SAID BODY; MEANS FORMING A SEAL BETWEEN SAID BODY AND SAID END MEMBERS.