Patent ID: 7128137

Claim:
A heat exchanger comprising: a shell having an inner chamber defined by an inside wall surface, and having at least one opening adjacent an end of the shell, the inside wall surface including a recessed section extending axially a distance from an end of the shell, the recessed section comprises a ridge that extends radially inwardly therefrom, and that defines a transition between the recessed section and the remaining portion of the shell inner wall surface; a tube bundle disposed within the inner chamber and comprising a plurality of tubes arranged together; a header plate attached to the tubes and positioned adjacent an end of the tube bundle, the header plate including an outside diameter having an axially projecting section that extends therefrom, and a radially projecting lip that extends from an end of the axially projecting section, wherein the axially projecting section and radially projecting lip are integral with the header plate, and wherein the outside diameter further comprises a shoulder at the transition with the axially projecting section, and wherein the shoulder is positioned against the ridge to provide a nested attachment junction between the header plate and the shell.