METHOD FOR SECURING TUBES TO TUBE PLATES Russian patent published in 2002 - IPC

FIELD: plastic metal working, namely, fastening tubes in tube plates of heat exchangers. SUBSTANCE: method comprises steps of forming shaped tip in the form of annular protrusion on outer surface of tube placed in detachable die having annular groove; fixing tube against its possible motion by applying to tube end axial compression effort; placing tube in tube plate opening having annular groove in such a way that annular protrusion of tube is arranged opposite relative to annular groove of opening; securing tube to tube plate at applying compression effort to its inner surface; preliminarily forming annular recess, for example, with triangular cross section on front surface of tube plate equidistantly relative to contour of opening; making shaped tip with additional outer bulge near tube end face; at mounting tube in opening of tube plate placing said bulge portion over front surface of tube plate; after fastening tube, expanding bulge portion and without unloading it applying compression effort to tube end. EFFECT: enhanced operational characteristics of tube-to-tube plate joints.