METHOD FOR SECURING TUBES TO TUBE PLATES Russian patent published in 2001 - IPC

FIELD: plastic metal working, namely securing tubes to tube plates of heat exchangers with use of effect of localized oriented plastic deformation of tube material. SUBSTANCE: method comprises steps of profiling tube end portion along length less than spacing between outer edges of annular grooves of tube opening of tube plate for making portion with curvilinear generatrix turned to tube axis; placing tube end into tube opening with minimum gap in such a way that profiled portion of tube is arranged symmetrically relative to annular grooves of tube opening; fastening tube at expanding it by two stages while applying to inner surface of tube compression effort; at first stage expanding tube in portion between outer edges of annular grooves at filling volume of annular grooves with tube material. EFFECT: guaranteed operational characteristics of joints of tube-to-tube plates. 6 dwg