Non-lubricated plug valve with plastic liner

Claim 1

A LINED PLUG VALVE COMPRISING A VALVE BODY HAVING A PLUG-RECEIVING OPENING THEREIN COMMUNICATING WITH FLOW PORTS IN THE SURFACE THEREOF, PLUG MEMBER MOUNTED ON SAID BODY FOR ROTATION WITHIN SAID OPENING, SAID PLUG MEMBER BEING OF LESSER CROSS-SECTION THAN SAID OPENING AND HAVING A FLOW PASSAGEWAY THERETHROUGH DISPOSED FOR ALIGNMENT WITH SAID PORTS, A HOLLOW DEFORMABLE PLASTIC LINER MOUNTED BETWEEN AND OCCUPYING SUBSTANTIALLY ALL OF THE SPACE BETWEEN SAID SURFACE OF SAID BODY OPENING AND THE EXTERIOR SURFACES OF SAID PLUG MEMBER, SAID LINER HAVING PORTS THERETHROUGH IN REGISTRATION WITH SAID FLOW PORTS AND HAVING A PLURALITY OF SLOTS IN THE EXTERIOR SURFACES THEREOF, SAID SLOTS BEING SPACED FROM SAID PORTS AND EXTENDING SUBSTANTIALLY FROM ONE TO THE OPPOSITE AXIAL END OF SAID LINER AND BEING OF LESSER DEPTH THAN THE THICKNESS OF SAID LINER, AND ADJUSTABLE MEANS FOR FORCING SAID PLUG MEMBER AXIALLY INTO SAID BODY OPENING AND LINER TO COMPRESS SAID LINER INTO TIGHT SEALING ENGAGEMENT WITH SAID SURFACES OF SAID BODY OPENING.