Closure means

Claim 1

CLOSURE MEANS FOR SEALING AN OPENING IN A PRESSURE VESSEL CASING COMPRISING: (A) LOAD BEARING PLUG MEANS ENGAGEABLE IN SAID OPENING IN TIGHTLY SECURED RELATION, THE OUTER SURFACE OF SAID PLUG MEANS HAVING AN AXIALLY EXTENDING FRUSTROCONICAL SEALING SURFACE, AND AN AXIALLY EXTENDING FRUSTRO-CONICAL SEALING SURFACE ON SAID CASING AROUND SAID OPENING IN COOPERATIVE ALIGNMENT WITH THE SEALING SURFACE OF SAID PLUG MEANS, DEFINING WITH SAID PLUG MEANS SEALING SURFACE A FIRST PAIR OF CONCENTRIC SEALING SURFACES, THE PLANES OF SAID FIRST PAIR OF FRUSTROCONICAL SEALING SURFACES INTERSECTING ONE ANOTHER; (B) SEALING MEANS CONSTRUCTED AND ARRANGED TO BE JOINED TO THE OPEN END OF SAID PRESSURE VESSEL AND THE OUTER SURFACE OF SAID PLUG MEANS IN BRIDGING RELATIONSHIP TO THE JOINT BETWEEN SAID PLUG MEANS AND SAID PRESSURE VESSEL, SAID SEALING MEANS INCLUDING A SECOND PAIR OF CONCENTRIC FRUSTRO-CONICAL SEALING SURFACES EXTENDING AXIALLY INWARDLY IN COOPERATIVE RELATIONSHIP WITH SAID FIRST PAIR OF OUTWARDLY EXTENDING CONCENTRIC SEALING SURFACES AND ALIGNED THEREWITH FOR SEALINGLY ENGAGING THE LATTER FOR PREVENTING FLUID LEAKAGE BETWEEN SAID PLUG MEANS AND SAID PRESSURE VESSEL CASING; (C) AND A PAIR OF RESILIENT, CONCENTRICALLY SPACED APART DEFLECTABLE LIPS OF HARD METAL OR THE LIKE CARRYING ONE OF SAID PAIRS OF SEALING SURFACES, THE INCLUDED ANGLE OF THE SEALING SURFACES ON SAID LIPS BEING NORMALLY LESS THAN THE INCLUDED ANGLE OF THE OTHER PAIR OF SEALING SURFACES, SAID LIPS BEING OPERATIVE FOR TRANSVERSE DEFLECTION TO ENGAGE THEIR SEALING SURFACE INTO MATING STRESSED SEALING ENGAGEMENT WITH THE OTHER PAIR OF SEALING SURFACES, THE INTERNAL ENERGY IN SAID LIPS CREATING A FLUID SEAL BETWEEN SAID SEALING SURFACES TO THEREBY SEAL THE JOINT BETWEEN SAID PLUG MEANS AND SAID PRESSURE VESSEL.