Patent ID: 6550533
Filing Date: 2003-04-22
Classification: F28D,F28F

Abstract:
A tube used in a heat exchanger, comprising:a plate folded in two so as to make two edges of the plate contact each other and form a flat tube, wherein: the plate comprises protrusions provided on each inner wall of the flat tube in a manner such that the heads of opposed protrusions on both the inner walls contact each other, the protrusions are arranged in an inclined checker pattern along the longitudinal direction of the tube, where the longitudinal spans of any two adjacent protrusions on each inclined line of the checker pattern partially overlap each other; the plate is clad with a brazing filler metal and the protrusions formed on a surface of the plate before the plate is folded, and the two edges of the plate and the heads of the opposed protrusions are respectively brazed after the plate is folded; the tube is placed between a pair of headers of a heat exchanger, which are provided for circulating refrigerant, and the tube has two ends which are respectively inserted into the pair of headers; and a predetermined number of first sets of the opposed protrusions, positioned closest to each end of the tube, are larger than the other protrusions in a manner such that their size along the longitudinal direction of the tube is larger, so as to improve rigidity.