GB624519A - Improvements in safety appliances for liquid immersed electric switches - Google Patents

Abstract

624,519. Oil-break switches; switch cases. ETABLISSEMENTS MERLIN & GERIN. Sept. 16, 1946, Nos. 27706 and 27707. Convention dates, Sept. 17, 1945 and March 12, 1946. [Class 38(v)] To avoid the risk of explosion and fire due to arcing in an oil break switch under fault conditions, the cover 10 of a switch tank 1, Fig. 1, is connected by a comparatively large vent pipe 11 to a large filter 12 capable of filtering the gases evolved without causing undue back pressure. In Fig. 5, the tank 1 is mounted within an outer casing 2 and the space between them is used for the vanes 21 of a centrifugal separator, which removes much of the suspended oil from the gases which escape from the tank and pass through the separator, orifice 26 and the filter 12 mounted below the separator. The oil which separates out can be withdrawn through a cock 23, and a float-operated warning device may be provided to indicate the level of the oil in the base of the separator. Figs. 2-4, (not shown), illustrate modifications in which filters are mounted in extensions of the casing or tank above or below the tank, together with various methods of venting the tanks. In each case the filtering material may be quartzous sand, glass wool, asbestos, porous earth or filtering candles and may be impregnated with oil to improve its smoke retaining properties, or liquids, such as a solution of sodium hyposulphite or sodium carbonate to remove decomposition products such as chlorine. The Specification as open to inspection under Sect. 91 describes and illustrates a construction in which the bursting of a membrane in the bottom of the tank allows the oil to flow from the switch tank into the filter. This subject-matter does not appear in the Specification as accepted.