Sequentially seated valve

Claim 1

A VALVE COMPRISING A BODY HAVING INLET AND OUTLET PASSGES COMMUNICATING AT THEIR INNER ENDS WITH A CYLINDRICAL VALVE CHAMBER, MEANS PROVIDING A CONICAL SEATING SURFACE ADJACENT THE INTERSECTION OF SAID INLET PASSAGE AND THE LOWER END OF SAID CHAMBER, A VALVE DISC POSITIONED IN SAID CHAMBER FOR MOVEMENT TOWARD AND AWAY FROM SAID SEATING SURFACE, A YOKE CARRIED BY SAID BODY, A VALVE STEM SUPPORTED BY SAID YOKE, MEANS CONNECTING THE LOWER END OF SAID STEM TO SAID DISC TO PREVENT SUBSTANTIAL RELATIVE MOVEMENT OF SAID STEM AND SAID DISC AXIALLY OF SAID STEM WHILE PERMITTING SAID STEM TO ROTATE OR TO MOVE RADIALLY A PREDETERMINED DISTANCE WITH RESPECT TO SAID DISC, SAID DISC HAVING A BOTTOM WALL PORTION PROVIDED WITH A CONICAL SEATING SURFACE ADAPTED TO SEALINGLY ENGAGE SAID SEATING SURFACE IN SAID VALVE CHAMBER TO CLOSE SAID VALVE AND HAVING AN ELONGATED BODY PORTION OF A DIAMETER SUBSTANTIALLY LESS THAN THE DIAMETER OF SAID VALVE CHAMBER, AND RELATIVELY NARROW UPPER AND LOWER WEAR AND GUIDE RING PORTIONS POSITIONED ADJACENT THE OPPOSITE ENDS OF SAID DISC BODY PORTION AND PROJECTING OUTWARDLY THEREFROM INTO CLOSE CLEARANCE RELATION WITH THE WALL OF SAID VALVE CHAMBER TO GUIDE SAID DISC IN ITS MOVEMENT TOWARD AND AWAY FROM SAID VALVE CHAMBER SEATING SURFACE, THE RADIAL CLEARANCE BETWEEN SAID UPPER AND LOWER RING PORTIONS AND SAID VALVE BODY CHAMBER BEING LESS THAN THE RADIAL CLEARANCE BETWEEN SAID STEM AND SAID DISC AND THE LOWER WEAR RING PORTION BEING ADJACENT THE BOTTOM OF SAID OUTLET OPENING WHEN SAID VALVE IS CLOSED, AND SAID LOWER WEAR RING PORTION COOPERATING WITH SAID VALVE CHAMBER WALL TO PREVENT THE PASSAGE OF HIGH PRESSURE FLUID FROM SAID INLET OPENING TO THE REGION OF SAID DISC BODY PORTION ABOVE SAID LOWER RING PORTION OT THEREBY MATERIALLY REDUCE THE SIDE THRUST TENDING TO URGE SAID DISC TOWARD SAID OULTLET OPENING.