GB541237A - Improvements in or relating to a.c. electric circuit-breakers of the gas-blast type - Google Patents

Abstract

541,237. Gas-blast switches. REYROLLE & CO., Ltd., A., and AMER, D. F. April 15, 1940. No. 6785. [Class 38 (v)] Switches employing an arc-quenching blast of gas, which may be externally produced and/or evolved by the arc from solid material and directed laterally or axially with respect to the direct arc-path between the contacts, have a cooling and de-ionizing unit which comprises a casing adapted to be connected to the switchcasing and housing a hollow insulator in which is a restricted aperture through which the gases are discharged into it. As applied to a switch incorporating features of Specification 536,451, the insulator G is carried by an earthed metal flange F, F<SP>1</SP> which is bolted at F<SP>3</SP> to the metal casing D<SP>1</SP> of the insulating housing D, the bolts serving also to secure a metal casing E provided with an insulating lining E<SP>3</SP> and discharge outlets E<SP>2</SP>. The casing E may be earthed, but is preferably insulated by the washer F<SP>2</SP> and bolt-shroud F<SP>4</SP>. The conical upper end of G may be spaced from housing D for the purpose stated in Specification 541,236, and carries a nozzle G<SP>1</SP> which may carry or be in contact with the arcing tips B<SP>1</SP>, C<SP>2</SP>. The lower end of G carries a conical perforated wall J and a cylindrical metal wall H to which is attached a further conical perforated wall K, the space between J, K being filled with metal packing, such as tubing, of copper or other metal of high heat and electric conductivity. Concentric metal tubes L also surround wall H, but in a modification, Fig. 5 (not shown), a metal spiral may be located in the cylindrical part of G with its outer edge engaging the latter and its inner edge anchored to the rod N which, in this form, extends into the upper conical part of G and carries an auxiliary electrode, for the purpose described in Specification 541,235. The insulator of Fig. 6 (not shown) is itself formed with a nozzle and carries a metal grid which is earthed through a resistance. A pair of cooling devices are provided intermediate its ends, the outer end being left open.