| 摘要 |
PURPOSE:To improve the heat transfer effect of fin tube by welding the following fin material by shallow pitch while bending one part in the fin radial direction to the welded fin side along the circumferential direction of the welded fin on the rear side in the welding direction against the pressurized roll. CONSTITUTION:The bending roll 13A is arranged at the rear side in the welding direction against the pressing roll 3, if one part in the fin radial direction is bent to the welded fin 12 side, at least, along the circumferential direction of welded fin 12, the space 14 between the welded fin and the fin material 2 becomes large. The pitch roll 4 is inserted in this space, the pitch roll 4 does not come in contact with the fin material 2, and the pitch between the fin material 2 and the welded fin 12 can be made small. Therefore, because the pitch P of welded fin can be made to a shallow pitch, the heat transfer effect of the fin tube can be increased. |
