METHOD FOR SECURING TUBES TO TUBE PLATES Russian patent published in 2004 - IPC

FIELD: plastic working of metals, possibly tube securing to tube plates of heat exchange apparatuses.

SUBSTANCE: method comprises steps of profiling tube ends for forming cylindrical tube end portions joined with tube through transition cone portion; forming on outer surface of loaded zone of end portions annular protrusion with trapezoidal cross section. Said protrusion is formed in detachable die with annular groove due to stepped radial squeezing of part of length of tube end portion for its subsequent expansion by drifting opening at simultaneously profiling inner surface of loaded zone. At stepped squeezing part of length of loaded zone of tube end portion is arranged by cantilever fashion relative to edge of annular groove of die and volume of said groove is partially filled with material of profiled end portion non-subjected to radial squeezing. During expansion process volume of annular groove of die is finally filled with tube material. Then tube end portion is placed in tube plate opening having annular grooves with trapezoidal and triangular cross sections; tube is fixed against possible movements and it is fixed.

EFFECT: enhanced reliability of securing tubes due to high-quality annular tightness zones between joined members.

9 dwg