Drainage structure for corrugated-fin heat exchanger

A drain structure for a corrugated-fin heat exchanger,

• the corrugated-fin heat exchanger being constructed by arranging a plurality of flat heat exchange tubes parallel to each other in a horizontal direction between a pair of opposing header pipes, joining, at a position between the plurality of flat heat exchange tubes, corrugated fins formed by alternately repeating peak folding portions and valley folding portions, and forming water flow passages from lug pieces that are obtained by obliquely cutting and raising flange portions extending along end portions of each of the plurality of flat heat exchange tubes in a width direction thereof,
• wherein a plurality of the lug pieces formed in the each of the plurality of flat heat exchange tubes are arrayed at appropriate intervals along a longitudinal direction of the each of the plurality of flat heat exchange tubes, and
• wherein a pitch (P) of each of the corrugated fins between a peak and a valley thereof, a width (L) of each of the lug pieces in a vertical direction thereof, and a thickness (T) of the each of the plurality of flat heat exchange tubes have a relationship of P×2≧L≧T.