US Patent 7073257 Shrinkage-free sealing method and structure of heat pipe

A shrinkage-free sealing structure is formed at an open end of a heat pipe by pressing one side of the open end towards the other side of the open end until the side walls of the open ends contact each other. Furthermore, the recess is pressed to have a curve which is the same as the curve of the outer circular wall of the heat pipe so that a double-layered recess is formed with a cross-sectional length larger than a semicircumference of the outer circular wall of the heat pipe.