Patent ID: 6898375

Claim:
A method of damming off a portion of an insulation space extending inwardly from an opening in a jacket wall outwardly circumscribing a fluid containment vessel and defining, with said jacket wall, said insulation space, said method comprising the steps of: providing a hollow body with open outer and inner sides spaced apart along an axis circumscribed by said hollow body; inserting said hollow body axially inwardly through said jacket wall opening to a sealing position; maintaining the inserted hollow body in said sealing position utilizing a locking/force exerting structure associated with said hollow body and positioned axially inwardly of said open outer side thereof; and securing an axially inwardly sloped, resiliently deflectable outer sealing lip to said open outer side, the secured lip extending exteriorly around the periphery of said open outer side, said outer sealing lip, when the inserted hollow body is maintained in said sealing position, being axially outwardly deflected and in sealing engagement with the outer side surface of said jacket wall around the periphery of said opening therein.