| 摘要 |
PURPOSE:To provide a heat transfer tube of a high thermal efficiency which is easy to manufacture by closely fixing a cylindrical body formed by turning thin plates each having a winding diameter substantially the same as the inner diameter of a tubular body provided at its one surface or both surfaces with a large number of depressions or through holes, to the inner surface of a tubular body having a smooth inner surface or a grooved inner surface. CONSTITUTION:A cylindrical body 2 is formed by thin plates each of which has an increased surface area of one surface or both surfaces as thin plates 3, 4, 5 and 6 and also has an outer diameter dimension substantially the same as the inner diameter of a tubular body 1. The thus formed cylindrical body 2 is turned around a core rod having a diameter which is slightly larger than the inner diameter of the tubular body 1. The cylindrical body 2 is inserted into the tubular body 1 together with the core rod, and then the fixing of both ends of the thin plate is released. The winding diameter of the cylindrical body 2 is expanded by an elastic reinstating force of the thin plate, and the winding force with respect to the core rod is loosened. Thus, the core rod can be drawn out of the tubular body 1 and can also be closely fixed to the inner surface 1a of the tubular body 1. Further, the core rod can be positively secured thereto by the method of extracting the tubular body 1 and the roll pressing method. The heat transfer efficiency is improved by the increase in the area of the front surface within the tubular body 1, generation of the turbulent flow and occurrence of the capillary tube phenomenon. |
