GB648630A - Improvements in or relating to electric circuit-breakers of the gas-blast type - Google Patents

Abstract

648,630. Gas-blast switches. REYROLLE & CO., Ltd., A., and AMER, D. F. April 23, 1948, No. 11264. [Class 38(v)] In a gas - blast circuit-breaker ir which the contacts separate within ar arcing enclosure maintained filled with gas under pressure, mean: are provided to increase the' gas pressure during the opening of the circuit-breaker sc as to obtain ar adequate blast of deionizing gas tc extinguish the arc In Fig. 1, the enclosure C containing the fixed contact C<SP>1</SP> and moving contact C<SP>2</SP> is maintained at a superatmospheric pressure by gas which is supplied from a reservoir B<SP>1</SP> through a reducing valve B<SP>2</SP>, the pressure being sufficient to provide an adequate dielectric break-down strength. The increase in the pressure occurs when the main blast valve B<SP>3</SP> is opened to cause the opening of the contacts by applying pressure to a piston C<SP>3</SP>. The increased pressure in the enclosure is also effective to open an exhaust valve E<SP>3</SP> which is moved by a diaphragm E<SP>4</SP> closing a chamber E<SP>5</SP> connected by. a bleed pipe E‹ to the enclosure. C. Hence, when the valve B3 is opened, the contact C<SP>2</SP> is retracted and the end of the arc rooted on this contact is blown by a blast of gas at the increased pressure on to the wall of a metallic skirt D and then to and through a nozzle E whereby the arc is extinguished. When the blast valve is closed the pressure in the enclosure returns to the initial pressure, the exhaust valve E<SP>3</SP> closes and the pressure on both sides of the piston C<SP>3</SP> is equalized by means of the bleed passage C<SP>5</SP> so that the contacts remain open. To reclose the circuit-breaker, a relief valve B<SP>4</SP> is opened and the sudden pressure-drop in the enclosure causes the piston C<SP>3</SP> to move the contact C<SP>2</SP> back into engagement with the fixed contact C<SP>1</SP>. The valve B<SP>4</SP> is then closed so that the pressure in the enclosure returns to its initial value. Figs. 2 and 3 (not shown), illustrate modifications of this arrangement in which additional blow-out nozzles are provided.