Primary manway closure redundant restraint

摘要

In combination, a vessel (10), opening means (16) in the vessel, a cover (18), flange means (20) surrounding the opening means, a primary closing means (22, 24) for the cover including a plurality of studs (22) securing the cover onto the vessel, the studs having inner ends threaded into openings (26) in the vessel, nuts (24) cooperating with the outer ends of each of the studs, secondary closing means (32, 34, 38, 40) for the cover including cylindrical clamp means (30, 32) made up of more than one piece, a protruding ledge (34) on the cover over which the clamp means extends, an annular groove (36) in the flange means into which the clamp means extends, a circular retaining ring (38) which surrounds the clamp means, a plurality of threaded openings (42) in the retaining ring, and a plurality of set screws (40) threaded into the openings, so that their ends force the clamp means into tight clamping engagement with the ledge on the cover and the groove in the flange means. The combination set forth above, including a groove (43) in the outer surface of the retaining ring, into which the ends of set screws come into contact. The combination set forth above, further including a plurality of spacer lugs (44) attached to the retaining ring, which spacer lugs contact the vessel so as to accurately position the retaining ring with respect to the clamp means.