| 摘要 |
PROBLEM TO BE SOLVED: To alleviate an abrupt contraction and expansion of a refrigerant channel at a connecting portion of a dimple tube to a header and to reduce a pressure loss of inputting or outputting refrigerant by providing a tubular portion existing no columnar part at an end to be inserted into a hollow header, and specifying a length of the tubular portion along a lengthwise direction of the tube. SOLUTION: A tube 11 is formed flatly by doubling a flat plate 20 and its folded and superposed side edges are brazed to form a tubular state. A first wall 21 and a second wall 22 are formed in a spaced-apart relation substantially parallel to the tube 11, and a refrigerant channel 23 is formed in a space surrounded by the walls 21, 22. Opposed walls 21, 22 are recessed from outside at the tube 11 to form a plurality of dimples 24, and a plurality of bulged parts 25 are formed at the channel 23 side. A length X mm of the tubular portion 21 is set to X<=15. Then, the abrupt contraction or abrupt expansion of the channel 23 is alleviated, thereby reducing its pressure loss. |
