Method for making lined valves

Claim 1

IN A METHOD OF FABRICATING A LINED PLUG VALVE WHICH INCLUDES A VALVE BODY HAVING A TRANSVERSE BORE THEREIN AND A VALVE PLUG FOR INSERTION IN SAID BORE HAVING SUFFICIENTLY SMALLER RADIAL DIMENSIONS THAN SAID BORE TO ESTABLISH AN ANNULAR CLEARANCE BETWEEN THE OPPOSED SURFACES THEREOF, ONE OF SAID OPPOSED SURFACES HAVING A PLURALITY OF SPACED INDENTATIONS OF PREDETERMINED CONFIGURATION AND DEPTH TO DEFINE INDENTED AND NON-INDENTED PORTIONS ON SAID ONE OF SAID OPPOSED SURFACES THEREIN, ONE OF SAID SURFACES BEING TAPERED, THE RADIAL DIMENSIONS OF SAID CLEARANCE OVERLYING SAID INDENTED SURFACE PORTIONS BEING SUBSTANTIALLY GREATER THAN THE RADIAL DIMENSIONS OF SAID CLEARANCE OVERLYING SAID NON-INDENTED SURFACE PORTIONS, THE STEPS OF FORMING TUBULAR LINER MEANS OF A FLUOROCARBON MATERIAL HAVING A COEFFICIENT OF THERMAL EXPANSION SUBSTANTIALLY GREATER THAN THAT OF SAID PLUG AND BODY AND WITH SAID LINER MEANS PROPORTIONED TO BE RECEIVED IN SAID CLEARANCE AND INITIALLY OF GREATER THICKNESS THAN THE MINIMUM CORRESPONDNG RADIAL DIMENSIONS OF SAID CLEARANCE, ASSEMBLING SAID LINER MEANS IN TELESCOPING OVERLYING RELATION WITH SAID INDENTED SURFACE, ASSEMBLY IN TELESCOPING RELATION WITH SAID IN LINER MEANS AND SAID INDENTED SURFACE A MEMBER HAVING THE SAME SURFACE CONTOUR AS THE OTHER OF SAID SURFACES, AND FORCING SAID SURFACES AXIALLY OF EACH OTHER IN THE DIRECTION OF THE SMALLER END OF SAID TAPERED SURFACE TO COMPRESS SAID LINER MEANS AND CAUSE THE MATERIAL THEREOF TO FLOW INTO SAID INDENTATIONS FORMING LINER PORTIONS OVERLYING AND RECEIVED IN SAID INDENTED SURFACE PORTIONS WHICH HAVE RADIAL DIMENSIONS SUBSTANTIALLY GREATER THAN THE RADIAL DIMENSIONS OF SAID LINER MEANS IN THE PORTIONS THEREOF OVERLYING SAID NON-INDENTED SURFACE PORTIONS AND WHICH ARE RETAINED IN SAID INDENTATIONS TO MAINTAIN SAID LINER MEANS IN CORRESPONDINGLY FIXED RELATION WITH SAID INDENTED SURFACE BOTH AXIALLY AND CIRCUMFERENTIALLY THEREOF.