Abstract: A fin tube heat exchanger has heat transfer fins disposed in an air flow and plural heat transfer tubes that are inserted in the heat transfer fins and disposed in a direction substantially orthogonal to a flow direction of the air flow. On the heat transfer fins, a set of guide fins and a set of guide fins arranged straightly from upstream to downstream in the flow direction of the air flow are formed, by cutting and raising, on the heat transfer fin surfaces on both sides of the heat transfer tubes. Straight lines that hypothetically interconnect the guide fins and the guide fins slant with respect to the flow direction of the air flow so as to guide the air flow in the vicinities of the heat transfer tubes to rear sides of the heat transfer tubes in the flow direction.

Abstract: A heat exchanger-use fin includes a fin body, collars and erect portions. The fin body has a plurality of holes. The collars surround the holes. The collars are disposed between two straight lines on a surface of the fin body. Outer peripheries of the collars contact the straight lines. The erect portions are positioned outside the two straight lines. Distal ends of the erect portions are in higher positions than distal ends of the collars relative to the surface of the fin body. A guide used with the fin includes first and second alternately arranged grooves. The second grooves are deeper than the first grooves. A method of using the guide includes slidably fitting the collars into one of the first grooves, and fitting the erect portions into the second groove adjacent to the first groove having the collars fitted therein.

Abstract: An air conditioner comprises an outdoor heat exchanger having a plate fin whose surface is treated to have water-sliding properties and water repellency and a drain pan arranged under the outdoor heat exchanger. There is a gap throughout between the lower end portion of the outdoor heat exchanger and the upper surface of the drain pan. Water droplets condensed when the outdoor heat exchanger operates as an evaporator fall on the drain pan from the lower end portion of the plate fin. Since the plate fin and the drain pan are not in contact with each other, there is no such case that ice adheres to the contact portion and frost develops therefrom.