| 摘要 |
PURPOSE:To provide a heat transfer tube of a high heat efficiency which is easy to manufacture by closely fixing a spiral wire made of fine wires of copper of a copper alloy, having a winding diameter of a dimension substantially equal to the diameter dimension of the tube inner diameter to the inner surface of a metal tube having a smooth inner surface or a grooved inner surface. CONSTITUTION:A fine wire 2 made of copper or a copper alloy is beforehand wound around a winding core rod having a diameter which is slightly smaller than the inner diameter dimension of a tubular body 1 at an equal pitch or at a dense pitch, and is inserted into the tubular body 1 together with the core rod when the fixing of both ends of the fine wire 2 is released, the winding diameter of the fine wire 2 becomes naturally large by a spring-back force of the fine wire 2, and the clamping on the core rod of a spiral wire 3 is loosened. Hence, the core rod can be drawn out of the tubular body 1, and the wire 3 is closely fixed to the inner surface 1a of the tubular body 1 by a spring-back stress. Thus, the wire 3 is positively secured thereto by the extraction method or the roll pressing method. Further, the heat transfer efficiency is improved by the increase in the inner surface area, generation of the turbulent flow, and occurrence of the capillary phenomenon. |
