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

FIELD: plastic metal working, possibly securing tubes to tube plates of U-shaped heat exchanging apparatuses.

SUBSTANCE: method comprises steps of profiling tube ends for forming on them cylindrical end portions joined through cone transition cone portions; placing formed end portion of tube into tube plate opening having inner and outer annular groves. Outer annular grove is in the form of annular recess in which sleeve of plastic material is arranged at minimum gap. Inner groove has triangular cross section. At placing tube end portion, its transition cone portion is arranged in front of said inner annular groove. Tube is fixed against possible motion due to axial compression of sleeve of plastic material and further axial displacement of tube relative to deformed sleeve at arranging transition cone portion of tube in front of inner annular groove of tube plate opening. Then tube is fastened in opening of tube plate by drifting tube and expanding its end portion to cone.

EFFECT: improved reliability of securing tubes to tube plates due to high-quality annular tightness zones on outer surface of tube end portions.

2 cl, 6 dwg