JPS646698A - Heat pipe and manufacture thereof - Google Patents

Abstract

PURPOSE:To heighten heat transfer coefficient by increasing the area of heating surface and by increasing capillary action, by constituting a cylindrical sealed pipe in such a manner that a polygonal cavity is provided in the pipe, and by making each wall convex in the center area, and by making each corner acute. CONSTITUTION:A sealed pipe 10 has a squarely prismatic cavity 11, and the center area of each inside wall 12 of a cavity 11 is made convex, protruding toward the center of a cavity in full length in the longer direction of the inside wall of a pipe, and each corner 13 is made acute by two each neighboring inside walls 12. The capillary effect produced in an operating fluid 20 sealed in the sealed pipe 10 under reduced pressure is large because the corner parts 13 are made at sharp angles. Accordingly reflux of operating fluid is performed efficiently without inserting any wick in the sealed pipe 10, or without forming any ribbed channels on the inside walls. Because the cavity is polygonally prismatic, the area of heating surface is larger than the case of cylindrical shape, so that heat transfer coefficient can be increased.