Abstract: A molecular sieve moisture absorption device for electrical apparatus containing a dielectric gas includes a box in which the molecular sieve is placed. The box is closed by a plate provided with a valve through which the inside of the box is evacuated. The plate is held in place on a shoulder of the box by the action of pressure difference between the inside and the outside of the box after the inside of the box has been evacuated. A gasket is placed between the plate and the shoulder to ensure that the inside volume of the box is leakproof. The device can be stored independently of the apparatus. When the device is mounted on the apparatus, evacuating the case of the apparatus causes the plate to separate from the box, thereby putting the molecular sieve into contact with the inside volume to be treated of the case.

Abstract: A gas-blast circuit-breaker includes a jacket filled with a dielectric gas. A mobile arc contact cooperates with a fixed arc contact within the jacket. The mobile arc contact is part of a mobile contact assembly which is displaceable axially in the jacket between a closed position and an open position. The mobile contact assembly includes a first tube carrying the mobile arc contact and a second tube, which is coaxial with the first tube, carrying a mobile permanent contact with a gas blast nozzle coupled thereto. A ring joins the first tube and the second tube to define a gas-blast chamber and a compression chamber on opposite sides of the ring. The compression chamber communicates with the gas-blast chamber. An annular piston having an annular recess closes the compression chamber. A compression spring influences the annular piston against a fixed front stop.