HEAT EXCHANGER

PURPOSE:To reduce buckling of corrugate fin by a metod wherein a plurality of flat tubes are employed and respective tubes are formed with large curved sections and small curved sections alternately while the curved sections are contacted. CONSTITUTION:Two pieces of flat tubes 1, 2 are formed with the large curved sections 1A, 2a and the small curved sections 1B, 2B alternately and respectively. Both of the tubes 1, 2 are arranged so that the large curved sections 1A, 2A of one flat tube are contacted with the small curved sections 1B, 2B of the other flat tube at the inside of the curved sections 1A, 2A and the mutual location of both tubes are determined by the contact. The inside radii of the large curved sections 1A, 2A and the outside radii of the small curved sections 1B, 2B are designed so as to be same substantially. According to this arrangement, places whereat the intervals between tubes are not determined may be reduced remarkably eve if the total sum of the number of stages of the tubes are equal with each other. Accordingly, the buckling of the fins 5 upon brazing may be reduced remarkably.