Seal arrangement for gate valve

Claim 1

IN A VALVE INCLUDING A BODY HAVING A TRANSVERSE BORE FOR FLUID FLOW THERETHROUGH AND HAVING A LATERAL BORE FOR RECEIVING A GATE ELEMENT FOR CLOSING AND OPENING THE TRANSVERSE BORE TO FLUID FLOW AND A MOVABLE VALVE STEM EXTENDING INTO THE BODY AND CONNECTED TO THE ELEMENT FOR OPENING AND CLOSING THE TRANSVERSE BORE TO FLUID FLOW ON RELATIVE MOVEMENT OF THE ELEMENT IN THE LATERAL BORE, THE IMPROVEMENT COMPRISING: (A) THERE BEING AN ENLARGEMENT IN THE BODY ENCIRCLING THE TRANSVERSE BORE AND BEING FORMED BY A CYLINDRICAL WALL EXTENDING FROM THE LATERAL BORE LONGITUDINALLY ALONG THE TRANSVERSE BORE AND DEFINING AN ANNULAR SURFACE SURROUNDING BUT SPACED FROM THE TRANSVERSE BORE AND AT ITS TERMINATION FORMING AN END WALL EXTENDING LATERALLY OF AND INTERSECTING THE TRANSVERSE BORE; (B) A CYLINDRICAL ELEMENT HAVING AN END PORTION WHICH ABUTS THE END WALL OF THE ENLARGEMENT AND A CYLINDRICAL EXTENSION WHICH EXTENDS FROM THE PORTION THAT ABUTS THE END WALL TOWARD THE LATERAL BORE AND TERMINATING THEREIN; (C) SAID CYLINDRICAL EXTENSION THROUGHOUT ITS EXTENT BEING OF SUBSTANTIALLY THE SAME INTERNAL DIAMETER AS THE TRANSVERSE BORE AND BEING NARROWER IN WIDTH THAN THE ENLARGEMENT TO FORM A RING-SHAPED OPENING SURROUNDING BUT SPACED FROM THE TRANSVERSE BORE, SUCH RING-SHAPED OPENING EXTENDING BETWEEN SAID CYLINDRICAL EXTENSION AND THE ANNULAR SURFACE OF THE ENLARGEMENT AND BETWEEN SAID END PORTION OF SAID CYLINDRICAL ELEMENT AND THE LATERAL BORE; (D) SEAL MEANS BETWEEN SAID END PORTION OF SAID CYLINDRICAL ELEMENT AND THE ANNULAR SURFACE OF THE ENLARGEMENT TO INHIBIT FLUID LEAKAGE THEREBETWEEN; (E) A RING-SHAPED MEMBER DISPOSED WITHIN THE RINGSHAPED OPENING FOR ENGAGING THE GATE ELEMENT WHEN IN CLOSED POSITION TO SEALINGLY ENGAGE THEREWITH; (F) SAID RING-SHAPED MEMBER INCLUDING AT ONE END A METAL RING TO FIT WITHIN THE RING-SHAPED ENLARGEMENT;