Hitachi, Ltd.

Showa Denko K.k.

Hitachi Engineering Services Co., Ltd.

Toru Tsubaki

Naoki Amano

Takeshi Takahashi

Hiromoto Ohno

Koji Sasaki

Toshio Ohi

Shin Tamata

Tokio Yamagiwa

Yasuhide Takeda

Tuneo Kishi

Koji Kurokawa

Naoyuki Yamamoto

Wataru Tamura

Yoichiro Koizumi

Koji Ito

Akio Nadamura

SF.sub.6 gas is collected from the inside of a gas insulated machine during maintenance and inspection and is refined. Compositions of the refined SF.sub.6 gas are analyzed and confirmed to be reusable at the site. In the process of SF.sub.6 gas collecting and refining, acidic gases are neutralized and removed by a dry method using filters and the refined SF.sub.6 gas is collected in a collecting tank. In particular, after the refining, the composition of the collected SF.sub.6 gas is measured and confirmed by analysis equipment to quantitatively confirm whether or not the refined SF.sub.6 gas is reusable.

System for collecting and refining SF.sub.6 gas and method therefor

A puffer-type gas insulated interrupter has stationary and moving main contacts, stationary and moving arc contacts for discharging an arc, and a puffer cylinder for electric arc suppression. At the time of current interruption, the puffer cylinder moves together with the moving arc contact to blow electric insulation gas to the arc between the stationary and moving arc contacts. The blown gas flows between the arc contacts and is then discharged through a gas discharge passage. A duplex puffer chamber is provided in the gas discharge passage near the moving arc contact. The duplex puffer chamber holds or confines the insulation gas, and causes the same to be heated and pressurized by the arc and to blow out toward the stationary arc contact. A gas flow from the duplex puffer chamber cooperates with a gas flow from the puffer cylinder to effectively suppress the arc, and therefore the gas pressure in the puffer cylinder can be reduced, so that an operating force for the interrupter can be reduced.

Gas insulated interrupter

A puffer type gas-insulated circuit breaker is adapted to, when its movable electrode separates from a stationary electrode, enable an insulating gas blow toward an occurring arc to extinguish the same. An insulated nozzle is provided to direct the gas toward the arc and forms a gas passage in cooperation with an insulating cover which covers the movable electrode. The insulated cover is formed of an insulating material which contains a filler for preventing energy lines of the arc from entering the cover. Furthermore, the insulated cover has a specific inductive capacity greater than a specific inductive capacity of the insulated nozzle so as to reduce the electric field strength at the front end of the movable electrode.

Puffer type gas-insulated circuit breaker

A gas-insulated switching device includes a bus bar-connecting conductor, within a cylindrical container, which connects one end of a circuit breaker portion, disposed wihtin the container, to a main bus bar mounted on the outer side of the container. The bus bar-connecting conductor is inclined relative to the axis of the container in such a manner that one end of the bus bar-connecting conductor connected to the main bus bar is situated closer to the other end of the breaker portion than to the one end of the breaker portion, and radially more outwardly of the breaker portion than the other end of the bus bar-connecting conductor connected to the one end of the breaker portion. As the bus bar-connecting conductor is inclined in the above manner, the device can be of a compact size without possibility of affecting the insulation between the bus bar-connecting conductor and the other end of the breaker portion by the voltage applied therebetween in the open or circuit-breaking state of the breaker portion.

Gas-insulated switching device

A three-phase combined type circuit breaker is disclosed which comprises a common housing, three-phase interrupting units in said common housing, movable contacts of the interrupting units connected through link mechanisms to operating devices for three phases respectively provided outside of the common housing, the switching operation thus being performed by phase. Rotary shafts are disposed in substantially the same plane in the link mechanisms. Each of the rotary shafts is provided with a connector for the movable contact, a connector for the operating device, and a sealing arrangement positioned between the two connectors for allowing the rotary shaft to rotate while holding the common housing in hermetic condition. This construction makes up a three-phase combined type circuit breaker capable of being operated by phase. The arrangement and construction of the three-phase rotary shafts simplifies maintenance and inspection of the interrupting units and the operating devices.

Three-phase combined type circuit breaker

Growing community of inventors

Hitachi, Japan

Toru Tsubaki