VACUUM VALVE WITH TRIGGER DISCHARGE DEVICE

PURPOSE:To prevent a trigger section from being short-circuited with metal grains and improve the life and reliability by providing projections on mating electrodes at positions apart from a trigger discharge device. CONSTITUTION:A trigger shaft 13 is fitted to the inside of a trigger insulating cylinder 12, and a trigger pin 14 is provided on its end face. A projection 20a is provided on the outer periphery of the face of a fixed electrode 20 facing a movable electrode 21, a step is formed between the trigger pin 14 and the face of the fixed electrode 20 near it, a projection 21a is likewise provided on the outer periphery side of the face of the movable electrode 21 facing the fixed electrode 20. If a trigger type vacuum valve is used as a closing unit, arcs are moved to the outer periphery side of the fixed electrode 20 just before the movable electrode 21 is brought into contact with the fixed electrode 20 and are not concentrated locally near the trigger pin 14 at the center. A trouble that the trigger pin 14 and the fixed electrode 20 are short-circuited with the molten metal is thereby prevented, and the life and reliability can be improved.