Abstract: A vacuum valve according to embodiments of the present disclosure comprise a prescribed shaped vacuum insulation vessel 1 having openings on its both ends, sealing metal fittings 2,3 configured to seal the openings of the vacuum insulation vessel 1 respectively, and a pair of contact points 5,6 which can be brought into contact or out of contact with each other and is arranged within the vacuum insulation vessel 1, wherein the vacuum insulation vessel 1 includes a base material layer 1c of aluminum oxide, a 1st oxidization promotion layer 1a whose oxygen combination was promoted, which 1st oxidization promotion layer 1a is formed on the inner circumference of the base material layer 1c, and a 2nd oxidization promotion layer 1b whose oxygen combination was promoted, which 2nd oxidization promotion layer 1b is formed on the outer circumference of the base material layer 1c.

Abstract: A vacuum valve according to embodiments of the present disclosure comprise a prescribed shaped vacuum insulation vessel 1 having openings on its both ends, sealing metal fittings 2,3 configured to seal the openings of the vacuum insulation vessel 1 respectively, and a pair of contact points 5,6 which can be brought into contact or out of contact with each other and is arranged within the vacuum insulation vessel 1, wherein the vacuum insulation vessel 1 includes a base material layer 1c of aluminum oxide, a 1st oxidization promotion layer la whose oxygen combination was promoted, which 1st oxidization promotion layer 1a is formed on the inner circumference of the base material layer 1c, and a 2nd oxidization promotion layer 1b whose oxygen combination was promoted, which 2nd oxidization promotion layer 1b is formed on the outer circumference of the base material layer 1c.

Abstract: According to one embodiment, a tank-type vacuum circuit breaker includes a tank, a vacuum valve provided in the tank, an insulating layer provided on an outer circumference of the vacuum valve, having a fixed side interface connecting portion and a movable side interface connecting portion, a grounding layer provided on an outer circumference of the insulating layer, a fixed side bushing having an interface connecting portion connected to the fixed side interface connecting portion, a fixed side porcelain tube to house the fixed side bushing, a movable side bushing having an interface connecting portion connected to the movable side interface connecting portion, a movable side porcelain tube to house the movable side bushing, and insulation gas filled in the tank, at an approximately atmospheric pressure.

Abstract: A switchgear has an insulating container filled with an insulating gas, a fixed current-carrying shaft fixed airtightly to one opening of the insulating container, a fixed contact provided on an end of the fixed current-carrying shaft in the insulating container, a movable contact configured to separably contact the fixed contact, a movable current-carrying shaft having the movable contact provided on an end and airtightly movably penetrating the other opening of the insulating container, and an operation mechanism coupled with the movable current-carrying shaft at an outside of the insulating container. The insulating container is constituted by a plurality of insulating layers, and the insulating layers are higher in dielectric constant as closer to an inside of the insulating container.

Abstract: A third electrode (8A) is soldered, via a support fitting (9) onto the inner surface of a support part (1a) which projects into the intermediate part of the inner surface of an insulation tube (1A). An arc generated between the fixed-side contact (5A) and the movable-side contact (5B) when the switch is opened is led from the outer periphery of the fixed-side contact (5A) via the third electrode (8A) to the movable-side contact (5B), in a so-called two-point switch, and the dielectric breakdown probability is thus reduced, particularly at low voltages. The third electrode may have its outer periphery exposed from the insulation tube and be used as one electrode when conditioning is carried out. By the use of this structure, the present invention is capable of meeting the demands for environmental protection and insulation reliability.

Abstract: A third electrode (8A) is soldered, via a support fitting (9) onto the inner surface of a support part (1a) which projects into the intermediate part of the inner surface of an insulation tube (1A). An arc generated between the fixed-side contact (5A) and the movable-side contact (5B) when the switch is opened is led from the outer periphery of the fixed-side contact (5A) via the third electrode (8A) to the movable-side contact (5B), in a so-called two-point switch, and the dielectric breakdown probability is thus reduced, particularly at low voltages.