| 摘要 |
PURPOSE:To promote the conduction of condensation heat of a liquid and to reduce the manufacturing cost of the heat transfer pipe by a method wherein a fine wire is coiled along one of the grooves formed at the lower part of the heat transfer pipe. CONSTITUTION:A couple of sinistral helical grooves 2 and 3 are continuously formed in the outer surface of the heat transfer pipe 1 in the longitudinal direction of the pipe leaving a recessed section 4 therebetween. The recessed section 4 performs the function of increasing the condensing effect of the liquid. In this case, when the interval between the helical grooves 2 and 3 is narrowed and the angle of inclination of the inclined surfaces between the recessed section 4 and the grooves 2 and 3 are made large, a favorable result is obtained in shaking off the condensed liquid from the pipe 1. Further, a flat and smooth heat transfer surface 7 of a comparatively large width is provided between the leads of the helical grooves so that the vapor of the liquid condenses on that surface and the fine wire 6 is coiled along the groove 3 at the lower part of the heat transfer pipe. In operation, the condensed liquid flowing along the sinistral helical groove 2 becomes larger in quantity and higher in speed as it flows toward the lower part of the heat transfer pipe 1 until a part of the liquid scatters from the groove 2. Accordingly, the thickness of the condensed liquid layer is kept smaller than a predetermined value over the entire length of the pipe and the liquid condenses efficiently. |
