Valve

Claim 1

A LINED ROTARY PLUG VALVE COMPRISING AN ANNULAR BODY PORTION, END CLOSURE PORTIONS HAVING A FLOW PASSAGE FORMED THEREIN REMOVABLY FIXED TO SAID BODY PORTION AND DEFINING WITH SAID BODY PORTION A VALVE CHAMBER, SUBSTANTIALLY INERT LINING MATERIAL FORMED ABOUT THE INTERIOR SURFACES OF SAID BODY PORTION AND SAID END CLOSURE PORTIONS, THE LINING MATERIAL OF EACH OF SAID END CLOSURE PORTIONS DEFINING ANNULAR SEAT RECESSES ABOUT THE FLOW PASSAGES THEREOF, REMOVABLE SEAT MEMBERS COMPOSED OF SUBSTANTIALLY INERT MATERIAL POSITIONED ONE WITHIN EACH OF SAID SEAT RECESSES, A ROTARY PLUG MEMBER HAVING SAID THROUGH PASSAGE FORMED THEREIN POSITIONED WITHIN SAID VALVE CHAMBER AND IN SEALING ENGAGEMENT WITH EACH OF SAID SEAT MEMBERS, SUBSTANTIALLY INERT LINING MATERIAL FORMED ABOUT THE INTERIOR AND EXTERIOR SURFACES OF SAID PLUG MEMBER AND DEFINING AN ELONGATE DRIVE OPENING, A LINED VALVE STEM HAVING A NONCIRCULAR PORTION THEREOF POSITIONED WITHIN SAID SLOT FOR IMPARTING ROTATION TO SAID PLUG MEMBER, THE LENGTH OF SAID DRIVE OPENING BEING GREATER THANT THE LENGTH OF SAID NONCIRCULAR PORTION THEREBY RESTRAINING MOVEMENT OF SAID PLUG MEMBER IN ONE POSITION OF SAID PLUG AND ALLOWING FREE AXIAL MOVEMENT OF THE PLUG MEMBER IN A SECOND POSITION THEREOF, SUBSTANTIALLY INERT MATERIAL FORMED ABOUT THE EXTERNAL SURFACES OF SAID STEM, MEANS INTERLOCKING SAID LINING MATERIAL WITH SAID BODY PORTION, WITH SAID END CLOSURE PORTIONS AND WITH SAID PLUG MEMBER TO PREVENT SEPARATION OF THE LINING MATERIAL.