| 摘要 |
<p>An inner fin (5), which is formed of a thin plate of an aluminum alloy having a corrugated section in a widthwise direction, includes a plurality of crest surfaces (7) extending parallel in a lengthwise direction, and a plurality of trough surfaces (6) extending parallel in the lengthwise direction. The crest surfaces and the trough surfaces are connected together by inclined surfaces (8). The crest surfaces are provided with concavities (10-13,20-23), which are shifted form each other in the lengthwise direction so that the concavities formed in the adjacent crest surfaces (7) are not aligned on the same line in the widthwise direction. The inner fin inserted into the tube partitions the passages which communicate with each other through the concavities. <IMAGE></p> |
