Flat heat transfer tube, manufacturing method of cross fin tube type heat exchanger having the same, and cross fin tube type heat exchanger manufactured by the same manufacturing method

摘要

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