FLAT HEAT TRANSMISSION TUBE, METHOD FOR MANUFACTURING CROSS-FIN-TUBE-TYPE HEAT EXCHANGER PROVIDED WITH SAME, CROSS-FIN-TUBE-TYPE HEAT EXCHANGER MANUFACTURED USING SAID METHOD

摘要

A flat heat transfer tube 1 according to the invention is a flat heat transfer tube 1 used for a cross fin tube type heat exchanger including the flat heat transfer tube 1 having a bending portion and a plurality of holes 2 extending through in a direction parallel with an axis direction of the flat heat transfer tube 1, and a plurality of plate fins bonded by welding to the flat heat transfer tube 1, wherein an interval t₁1 between an outer surface of the flat heat transfer tube 1 and an inner surface of the hole 2 of a portion which is curved with a small radius of curvature during bending is larger than an interval t₁2 between an outer surface of the flat heat transfer tube 1 and an inner surface of the hole 2 of a portion which is curved with a large radius of curvature during bending in a cross section of a portion of the flat heat transfer tube 1 which corresponds to the bending portion before bending.