PURPOSE: To prevent the temperature rise of the junction of a metallic foil conductor and an external lead, and to prevent the foil shortage and the breaking of a sealing tube by cutting the metallic foil conductor in an axial direction, and by connecting each of the cut metallic foil conductor with an intermediate lead.
CONSTITUTION: Electrode mounts 3, 3 inserted into sealing tubes 2, 2 are formed out of an electrode shaft 5 provided with an electrode oil 4 on the point, a first metallic foil conductor 11 with which the base part of the electrode shaft 5 is welded, an intermediate lead 10 welded with the intermediate lead 10, a second metallic foil conductor 12 welded with the intermediate lead 10, and of the external lead 7 made of molybdenum and so on, welded with the metallic foil conductor 12. The metallic foil conductor is parted in an axial direction, and, since the metallic foil conductors thus parted are connected with each other through the intermediate lead, a contact area is small at the junction of the metallic foil conductor and the intermediate lead. The junction will be a thermal induction resistant point in the thermal induction route of the electrode mount, and the temperature rise of the junction of the metallic foil conductor and the external lead can thus be prevented.
ISHIGAMI TOSHIHIKO
YOTSUYANAGI MASAHIKO
HIRUTA TOSHIO
