Bellows assembly for a vacuum container in a plasma devices

Object: To permit uniform and efficient heating of a bellows assembly and ready manufacture and maintenance. Structure: The bellows has ridge portions and groove portions, with an insulating refractory material fitted in the groove portions. The insulating refractory materials has a structure such that two longitudinally extending parallel sheath heaters are buried within it. Thus, it is possible to sufficiently heat the tip portions directed toward the interior of the bellows and also increase the heating efficiency with an increased heat radiation area. Further, the insulating refractory material with sheath heaters buried in it is divided into a plurality of blocks to facilitate manufacture and maintenance of the bellows. (Kamimura, M.)