Patent ID: 7185698

Claim:
A heat exchanger for heating cryogenic fluids comprising an external shell defining a closed interior and having a tube plate having multiple tube openings disposed in said shell transversely to the longitudinal extent of said shell so as to divide said shell into an entry side including an entry chamber for cold fluids to enter said shell and a heating side where heating fluids warm said cryogenic fluids, a plurality of heat transfer tubes extending through said plate tube openings and into said heating side whereby cold fluid passes from said entry chamber into said tubes, said plate having a cold side adjacent said entry side wherein that plate cold surface is in contact with said cryogenic fluid and a hot side adjacent said heating side wherein that plate hot surface is in contact with heating fluid within the shell, and a layer of thermal insulating material selected from the class of PTFE, metal jacketed cork and micarta attached to at least one of said hot and cold surfaces of said plate so as to achieve a temperature differential of less than approximately 300° F. between said hot and cold surfaces of said plate so as to protect said plate from thermal stress.