This invention deals generally with a method of assembling heat pipes into larger structures, and more specifically with a method of maintaining good thermal contact between a heat pipe and an assembly into which it is placed.
Expanding a heat pipe casing into contact with a surrounding assembly is not new. The method has been suggested in the patent literature many times, particularly as a method of attaching one or more fins to the outside of a heat pipe casing. For example, U.S. Pat. No. 5,412,535 by Chao et al suggests just such a method by either pulling a mandrel through the tube which will become the casing or by expanding the tube with hydraulic pressure. However, what may not be appreciated about such techniques is that they require the subsequent manufacture of the tubing into an operating heat pipe. That means that the entire assembly must undergo the processing of the heat pipe, and thus the materials of the entire assembly must be compatible with the procedure of processing the heat pipe. This may mean making compromises between the choice of materials and the processing techniques. Furthermore, even with compatible materials, a much larger assembly must be processed, and it also means that any failure during the manufacture of the heat pipe causes the loss of an entire assembly instead of just a single heat pipe.