METHOD FOR MAKING RIBBED CONVECTIVE TUBE OF HEAT EXCHANGE APPARATUS Russian patent published in 2002 - IPC

FIELD: heat and power engineering, possibly manufacture of convective tubes with ribs. SUBSTANCE: method comprises steps of placing on tube metallic discs with inner diameter equal to nominal diameter of outer surface of tube; fixing discs in axial direction and joining them with tube by plastically deforming the last due to forming onto inner surface of tube multirow axial or multistart helical grooves with semicircular cross section in order to make on outer surface of tube protrusions with semicircular cross section. Length value of chord of semicircle exceeds by 3-4 times width value of metallic disc. When thick-wall metallic discs are used surface of their contact with tube is in the form of wedge with doubled apex angle. EFFECT: lowered labor consumption for making convective tube. 2 cl, 4 dwg