| 摘要 |
PURPOSE:To delay the generation and development of frost at the tip end in the air suction side direction of a fin and prevent the deterioration of ventilating characteristics by suppressing heat transfer performance in the air suction direction side of the group of fins. CONSTITUTION:Protuberances 3a are formed at the air suction direction side of a fin collar 3. On the contrary, a circular configuration 3b is formed at the air blow-off direction side of the fin collar 3. Accordingly, clearances 3c are produced at the contacting section between the fin collar 3 and the heat transfer tube 2 in case the heat transfer tube 2, whose outer periphery is formed into circular configuration, is adhered to the fin 1 having the protuberances 3a by the means of tube expanding or the like. According to this method, the heat transfer performance at the air suction direction side may be suppressed and frosting in the same side may be prevented. |
