摘要 |
<p>Firstly, a heat transfer tube, in which grooves are formed on its inside surface in groove working step (1) and then its forming is applied in forming step (2), is softened in annealing step (3). Then, the tube is coiled in line in coiling in-line step (4). Here, while supplied in the length direction, the heat transfer tube is heated and cooled in the annealing step (3). Further, in the coiling in-line step (4), the heat transfer tube is coiled in line on a body of bobbin, so that works of installing the heat transfer tube to the bobbin can be simplified. <IMAGE></p> |