Closure for pressurized vessels

Claim 1

A HOUSING HAVING AN OPENING BOUNDED BY A FIXED MARGINAL, ANNULAR RADIALLY DISPOSED SURFACE, SAID HOUSING HAVING AN AXIALLY EXTENDING GUIDE MEANS RADIALLY INWARD OF SAID RADIAL SURFACE; AXIALLY SHIFTABLE ANNULAR SEAL MEANS MOUNTED BY SAID GUIDE MEANS RADIALLY INWARD OF SAID RADIALLY DISPOSED SURFACE, SAID SEAL COMPRISING A METALLIC RING WITH A RADIALLY OUTER, AXIALLY TAPERING, PERIPHERAL SURFACE PORTION OF DECREASING DIAMETER OUTWARDLY LEADING TO ITS OUTER EDGE, AND AXIALLY SPACED INNER AND OUTER RADIAL END SURFACES; A CLOSURE DOOR FOR SAID OPENING HINGED TO SAID HOUSING AT ONE SIDE THEREOF AND HAVING A COMPLEMENTARY, AXIALLY TAPERING, INTERIOR RING SURFACE SHAPED TO ENGAGE WITH THE AXIALLY TAPERING SURFACE OF SAID METALLIC RING; MEANS FOR PRESSURIZING THE INTERIOR OF THE HOUSING; THE ANNULAR RADIAL SURFACE BOUNDING SAID OPENING BEING LOCATED INTERMEDIATE SAID AXIALLY SPACED INNER AND OUTER END SURFACES OF THE METALLIC RING AND ABUTTING WITH AN ANNULAR RADIAL SURFACE ON SAID CLOSURE DOOR WHEN THE DOOR IS IN CLOSED POSITION; AND RING MEANS OF DEFORMABLE MATERIAL IN ENGAGEMENT BETWEEN THE METALLIC RING AND DOOR AND BETWEEN THE METALLIC RING AND HOUSING NEAR THE ENDS OF SAID METALLIC RING SAID AXIALLY INNER RADIAL END SURFACE BEING OF GREATER AREA THAN SAID AXIALLY OUTER RADIAL END SURFACE SO THAT THE PRESSURE CONDITION WITHIN SAID HOUSING ACTS TO MAINTAIN SEALED ENGAGEMENT OF SAID TAPERING SURFACES.