Specification :

A manlid for a tubular pressure vessel has a one-piece pressed stainless steel skin having an upwardly facing undulating annular groove and a downwardly-facing tapered annular seal groove. The lid assembly is provided with an inner reinforcing member located in the upwardly facing annular groove and an outer, annular peripheral reinforcing member located across the inner reinforcing member and having one arm in abutment with the exterior surface of the seal groove. The inner and outer reinforcing members are formed into a number of angularly-spaced lugs for receipt of conventional threaded swing bolts for securing the manlid in position. The provision of an inner reinforcing member between the pressed skin and the outer reinforcing member allows a pressed skin from a lower pressure-rated manlid to be used in a higher pressure-rated design.