Importance

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Abstract

A gas-blast switch containing both a stationary and a movable contact element. At one of these contact elements there is arranged a blast nozzle whose inlet chamber or compartment is connected with the outlet of a pump chamber containing an extinguishing gas and which can be placed under pressure during the cutoff stroke. Between the inlet chamber of the blast nozzle and the pump chamber there is a valve arrangement which is pre-biased in the closing direction. The valve arrangement responds when there is an excess pressure in the pump chamber and opens in the direction of the inlet chamber or compartment. To prevent escape of the extinguishing gas heated by the arc at the region of the blast nozzle, and thus, placed under pressure, and therefore, to also reduce the mechanical and thermal loading of the blast nozzle, the valve arrangement comprises a switching valve which, in the rest position, connects at least part of the inlet chamber of the blast nozzle with the space or chamber surrounding such blast nozzle and upon response of such switching valve disconnects the aforesaid part of the inlet chamber from the space surrounding the inlet chamber of the blast nozzle.

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First Claim