Closures for pressure vessels

Claim 1

A CLOSURE FOR SEALINGLY CLOSING A NON-CIRCULAR OPENING IN A PRESSURE VESSEL WHEREIN SAID OPENING IS BOUNDED BY INTERNAL SEAT DEFINING MEANS AND THE LATTER IS BOUNDED BY A SUBSTANTIALLY FLAT OUTER SURFACE PORTION OF SAID VESSEL, AND SAID CLOSURE IS INSERTED INTO THE PRESSURE VESSEL THROUGH THE OPENING TO BE CLOSED AND THEN MOVED INTO COOPERATIVE RELATION WITH SAID INTERNAL SEAT DEFINING MEANS TO SEALINGLY CLOSE THE OPENING; SAID CLOSURE COMPRISING A SUBSTANTIALLY FLAT BODY PORTION, A PERIPHERAL SKIRT PORTION EXTENDING DOWNWARDLY WITH RESPECT TO SAID BODY PORTION AND TERMINATING IN A PERIPHERAL LATERALLY EXTENDING FLANGE, SAID SKIRT AND FLANGE DEFINING A SEAT ADAPTED TO SUPPORT A RESILIENT GASKET MEMBER IN FLUID TIGHT SEALING RELATION WITH SAID PRESSURE VESSEL INTERNAL SEAT DEFINING MEANS; AND OPERATOR MEANS FOR MOVING SAID CLOSURE INTO CLOSED POSITION WITH RESPECT TO SAID VESSEL OPENING, SAID OPERATOR MEANS INCLUDING A NORMALLY STRAIGHT SHAFT TERMINATING AT EACH END IN A SUBSTANTIALLY PERPENDICULAR LEG, AND A PAIR OF SPACED APART SUPPORT MEMBERS EXTENDING UPWARDLY FROM SAID CLOSURE BODY PORTION, EACH OF SAID SUPPORT MEMBERS INCLUDING MEANS SUPPORTING SAID SHAFT FOR ROTATION ABOUT THE LONGITUDINAL AXIS OF SAID SHAFT, SAID MEANS BEING LOCATED BETWEEN SAID SHAFT LEGS AND SAID SHAFT AND SHAFT LEGS HAVING LENGTHS PREDETERMINED SO THAT, WHEN SAID CLOSURE IS POSITIONED FOR MOVEMENT INTO CLOSED POSITION, SAID SHAFT STRADDLES A DIMENSION OF SAID OPENING AND THE FOOT OF EACH OF SAID LEGS CAN BE BROUGHT INTO CONTACT WITH SAID FLAT OUTER SURFACE OF SAID VESSEL SURROUNDING SAID OPENING, THE LENGTH OF EACH LEG BEING GREATER THAN THE DISTANCE FROM SAID SHAFT SUPPORT MEANS TO SAID FLAT VESSEL OUTER SURFACE PORTION WHEN SAID CLOSURE IS IN CLOSED POSITION WHEREBY ROTATION OF SAID SHAFT TO MOVE SAID LEGS OVERCENTER WITH RESPECT TO SAID SHAFT SUPPORT MEANS CAMS SAID CLOSURE OUTWARDLY TOWARD SAID OPENING TO COMPRESS A RESILIENT GASKET MEMBER LOCATED BETWEEN SAID CLOSURE SEAT AND SAID VESSEL INTERNAL SEAT AND THEREBY SEAL SAID OPENING, AND SAID LEGS FLEX THE PORTIONS OF SAID SHAFT LOCATED BETWEEN SAID SHAFT SUPPORTS AND LEGS OUTWARDLY WITH RESPECT TO SAID OPENING TO MAINTAIN A CONTINUOUS PRESSURE BIASING SAID CLOSURE TOWARD SAID VESSEL INTERNAL SEAT.