US Patent 7193172 Gas-insulated switchgear tank

In a gas-insulated switchgear tank in which an electric insulating characteristic is improved by a gas, and which has a vacuum circuit-breaker, a disconnecting switch, and a container in which container the vacuum circuit-breaker and the disconnecting switch are arranged and an inside of which container is adapted to be hermetically sealed and filled with the gas in such a manner that the vacuum circuit-breaker and the disconnecting switch are at least partially surrounded by the gas, the gas includes N2 and O2.