Method for making ball valves

Claim 1

THE PROCESS OF FINISHING AN UNLAPPED SEAT RING FOR USE IN A HIGH PRESSURE BALL VALVE OF THE TYPE INCLUDING A HARD SEAT RING HAVING A BALL-CONTACTING SURFACE AND A BALL POSITIONABLE AGAINST THE BALL-CONTACTING SURFACE OF THE SEAT RING TO SHUT OFF ESSENTIALLY ALL FLOW OF FLUID THROUGH THE VALVE, COMPRISING THE STEPS OF: (A) ASSEMBLING THE UNLAPPED SEAT RING AND A BALL OF CERAMIC MATERIAL SUBSTANTIALLY HARDER THAN THE MATERIAL FROM WHICH THE SEAT RING IS MADE, AND CAPABLE OF PRODUCING A BURNISHED SURFACE UPON SAID SEAT RING UPON REPEATED ENGAGEMENT THEREWITH INTO A BALL VALVE, (B) CYCLING THE ASSEMBLED BALL VALVE BETWEEN ITS OPEN AND CLOSED CONDITIONS TO ENGAGE THE BALL WITH THE UNLAPPED SEAT RING, AND (C) REPEATING THE CYCLING STEP FOR A PLURALITY OF TIMES UNTIL THE BALL PRODUCES A BURNISHED BALL-CONTACTING SURFACE UPON THE SEAT RING EFFECTIVE IN COOPERATION WITH THE SURFACE OF THE BALL TO PROVIDE AN ESSENTIALLY FLUID TIGHT SEAL BETWEEN THE SEAT RING AND THE BALL WHEN THE VALVE IS IN ITS CLOSED CONDITION.