MANUFACTURE OF HEAT TRANSFER TUBE FOR HEAT EXCHANGER WITH FINS

摘要

PURPOSE:To protect a crack based on stress in a hair pin tube part from taking place by providing plural grooves only on the insides of a group of tubes within both ends of a group of flat sheet fins and making the tube thickness of a non-groove part larger than the bottom thickness of a groove part. CONSTITUTION:A flat sheet 10 is composed of a part of grooves 8 forming plural grooves or evennesses and a non-groove part 9 larger in thickness than the bottom of the part of grooves 8. In addition, the length of the part of grooves or l8 is made equal to the length of the tube put within both ends of a group of flat sheet fins and the length of the non-groove part or l9 is worked so that it is equal to the thickness of the hair pin tube part. Then, the ends of the flat sheet 10 are wound up and passed through a die 11 so that the grooves are located inside to form a tube, continuously weld a seam part 12 and manufacture a refrigerant tube 14.