US Patent 7854254 Systems and methods for making seals in heat exchangers

Systems and methods for improving heat exchangers by implementing self-energizing seals. In one embodiment, a U-tube heat exchanger includes a shell enclosure, a tube sheet, a closure and a set of tubes welded to the tube sheet. The tube sheet separates first and second chambers from a third chamber in the shell enclosure. The closure seals the first and second chambers. Each tube extends from the first chamber, through the third chamber to the second chamber. The improvement comprises a seal between the shell enclosure and either the closure or the tube sheet. The seal includes conically tapered sealing surfaces on the shell enclosure and closure or tube sheet which form a wedge-shaped gap. A seal ring having surfaces complementary to the sealing surfaces of the shell enclosure and closure or tube sheet is positioned between the sealing surfaces to form a self-energized seal.