| 摘要 |
PROBLEM TO BE SOLVED: To prevent the reduction of cutoff performance by the residual insulating gas by forming the cross sectional shape of support sections into a slender shape longer in length in the axial direction of a cooling tube than in the peripheral direction of the cooling tube. SOLUTION: Support sections 18a are provided at positions of 180 deg. from each other, and the cross sectional shape of the support sections 18a is set to a flat shape. The cross sectional shape is a slender rectangular shape having the length (t) in the peripheral direction of a slender rectangular cooling tube and the length L in the axial direction. A fixed arcing electrode 4a is provided between a pair of support sections 18a, the fixed arcing electrode 4a has a circular cross sectional shape, and it is protruded from the support sections 18a at the same value in both axial directions of the cooling tube. Since the shape of the support sections 18a is made the slender rectangular shape, the change of the cross sectional area is small, and the wave making resistance of insulating gas is reduced. The high-temperature insulating gas is prevented from being left to reduce cutoff performance.
|
