| 摘要 |
PURPOSE:To prevent the trouble of an air conditioner caused by remaining burr cut off at the time of expanding a tube by rolling up a metal plate to a tube-like state and arranging a thin part at the side part of metal plate, so as to form a recessed part in the inner circumferential face of connected part of a heat transfer tube, continuously welding the connected part. CONSTITUTION:The metal plate 7, which the thickness at both end parts is thinned, is rolled up and both the end parts are brought into contact with face to face, to make it the tube-like state. Next, the connecting part 10 is continuously welded, to make the heat transfer tube 9. Then, the burr 11 is developed, but as the thickness at the constant length part from the connecting part 10 is thinned, the inner diameter only at this part is larger than that of the other part. Therefore, the end part of burr 11 is not projected to inner side from the inner face of heat transfer tube 8. And, at the time of using the heat transfer tube 9 as a heat exchanger for the air conditioner, the tube is expanded by using a jig, but the burr 11 existing in the connected part 10 is not projected to the inner face side, because of thin thickness at the inside of tube near the connected part, and the burr 11 is not cut off by the jig. As a result, the cause of trouble which the burr is remained in the heat exchanger, is not happened.
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