Valve and valve disc

Claim 1

IN A VALVE BODY HAVING MEANS DEFINING A VALVE SEAT, A VALVE STEM EXTENDING AXIALLY INTO SAID VALVE BODY, A VALVE BODY PORTION FOR AXIALLY GUIDING SAID VALVE STEM HAVING A SEALING SURFACE DISPOSED CIRCUMFERENTIALLY OF SAID VALVE STEM INTERIORLY OF SAID VALVE BODY, A RESILIENT VALVE DISC MOUNTED IN OPERATION ON SAID VALVE STEM AND HAVING A FIRST PORTION COMPRISING A FIRST SURFACE SEATABLE ON SAID SEAT FOR CLOSING SAID VALVE AND A SECOND PORTION COMPRISING A SECOND SURFACE SEATABLE ON SAID SEALING SURFACE FOR PREVENTING LEAKAGE ALONG SAID VALVE STEM WHEN SAID VALVE DISC IS UNSEATED TO ALLOW FLUID FLOW THROUGH SAID VALVE BODY, SAID VALVE STEM BEING MOUNTED IN SAID VALVE BODY PORTION FOR SELECTIVE MOVEMENT AXIALLY VARIABLY IN A DIRECTION TOWARD SAID SEAT FOR SEATING SAID VALVE DISC ON SAID SEAT TO PRECLUDE FLUID FLOW THROUGH SAID VALVE BODY AND IN AN OPPOSITE DIRECTION TO UNSEAT SAID DISC TO ALLOW FLUID FLOW AND MOVABLE AXIALLY IN SAID OPPOSITE DIRECTION TO SEAT SAID SECOND SURFACE ON SAID SEATING SURFACE TO PRECLUDE SAID LEAKAGE ALONG SAID VALVE STEM, A MEMBER SECURED TO SAID VALVE STEM FOR HOLDING SAID VALVE DISC DISPOSED IN OPERATION INTERNALLY OF SAID DISC AND HAVING A RADIAL FLANGE EXTENDING RADIALLY SUFFICIENTLY TO APPLY A PRESSURE TO SAID FIRST SURFACE SEATABLE ON SAID SEAT IN DEPENDENCE UPON THE AXIAL POSITION OF SAID VALVE STEM, SAID MEMBER COMPRISING A CUP-SHAPED PORTION, SAID FLANGE BEING DISPOSED EXTENDING RADIALLY OUTWARDLY OF SAID CUP-SHAPED PORTION CIRCUMFERENTIALLY OF AN OPEN END OF SAID CUP-SHAPED PORTION, SAID DISC COMPRISING A CAVITY FOR RECEIVING SAID MEMBER AND HAVING SAID SECOND PORTION DISPOSED OVER SAID CUP-SHAPED PORTION INCLUDING SAID SECOND SURFACE CIRCUMFERENTIALLY OF SAID VALVE STEM POSITIONABLE IN ENGAGEMENT WITH SAID SEALING SURFACE TO EFFECTIVELY DEFINE A SEAL BETWEEN SAID DISC AND SAID VALVE BODY PORTION TO PRECLUDE FLUID LEAKAGE OUTWARDLY OF SAID VALVE BODY ALONG SAID VALVE STEM.