METHOD FOR SECURING TUBES IN TUBE PLATES Russian patent published in 1999 - IPC

FIELD: plastic metal working, namely processes for securing tubes in tube plates by means of localized directed plastic deformation of tube material. SUBSTANCE: method for securing tubes in tube plates of heat-exchange U-shaped apparatus comprises steps of mounting U-shaped tube simultaneously in two openings of tube plate and securing tube in plate by expansion; making annular grooves in openings of tube plate; preliminarily placing each end of tube mounted in openings of tube wall over front surface of tube plate; forming annular trapezoidal cross section protrusions on outer surface of protruding tube ends with number of protrusions corresponding to that of grooves; finally mounting tube at coinciding annular protrusions on outer surface of tube end with annular grooves in openings of tube plate. EFFECT: normalized force action of tube upon tube plate, enhanced stable strength and fluid tightness characteristics of assembly, possibility of multiple use of tube plate. 5 dwg