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

FIELD: plastic metal working, namely manufacture of heat exchange apparatuses. SUBSTANCE: method comprises steps of making annular turning on inner surface of each end of tube; placing in said turning sleeve made of cladding material and having shaped ends with triangle protrusions mutually joined by their bases; arranging free shaped end of sleeve over tube end; reducing tube end with sleeve for making transition cone portion of tube; then forming in outer surface of tube outer annular bulge with trapezoidal cross section by applying axial effort to tube end in such a way that to embed protrusions of sleeve into tube material for filling space between said protrusions with tube material; at placing tube in opening of tube plate, arranging cone portion of tube in range of length of inner annular triangle cross section groove of tube plate; matching outer annular bulge of tube with outer annular groove of tube plate opening; fixing tube against its possible motion and fastening it in opening of tube plate by applying compression effort to inner surface of tube; at fastening process forming inner annular bulge of tube whose cross section corresponds to cross section of inner annular groove. EFFECT: enhanced strength, tightness and corrosion resistance of rolled joints. 1 dwg, 2 tbl, 1 ex