Abstract: his paper introduces several items related to the setting of expansion joint in the design of fixed tube sheet heat exchanger, including the explanation of the setting principle of expansion joint, i.e. the different expansion coefficients of the tube and the shell leads to overhigh differential expansion, resulting in non-conforming shell tube tensile stress, heat exchange tube tensile or compression stress, and heat exchange tube pulling force, so expansion joint needs to be set. The limiting conditions of allowing the thinning of tube body when the expansion joint is connected with the tube body by butt welding are introduced. Also the determination of the setting position of expansion joint is discussed. For vertical heat exchangers, the expansion joint is preferably set below the lug support, while for horizontal heat exchangers, it is preferably set on the side with less constraint of pipeline.

Key words: fixed tube sheet exchanger, expansion joint, difference in temperature, differential thermal expansions, barrel connection, set position, hydraulic testing