Patent GB-408077-A (GB)
Title: Improvements in electric circuit-breakers
IPC: H01H33/96
Filed: 1933-01-23
Abstract: 408,077. High-tension switches; arcrupturing in switches. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET, Võsteras, Sweden. Jan. 23, 1933, No. 2165. Convention date, Jan. 23, 1932. [Class 38 (v).] A circuit-breaker comprises a chamber enclosing, in the closed position of the breaker, the points of fixed and movable contacts, which chamber communicates with another chamber, and one or both chambers contain an extinguishing liquid and are changeable in volume by means of movable parts of the walls, which parts are actuated by the pressure developed by the arc. The chambers intercommunicate principally by a channel traversed by the arc and by a flow of extinguishing fluid produced by the change of volume of the chambers, which flow is drawn from one chamber through the channel into the other. The fixed contact 1 and movable contact 2 engage within a chamber 6 that is bounded by a spring-controlled piston 10 and a barrier 15 having an aperture 16 by which the chamber 6 communicates with a chamber 5. The piston 10 is secured by rods 11 to a smaller piston 9 in the chamber 5, and both chambers contain fluid. When the contacts separate, an arc is drawn and the pressure acts on both pistons 9, 10 but as 10 is larger it is moved upwards to expand chamber 6 and contract 5. Thus, as the arc is drawn down through the hole 16 it is met by a stream of fluid impelled by piston 9 and so ruptured. The casing 8 is fixed, but in a modification, Fig. 2 (not shown), it forms the connection between the pistons and moves with them, and a series of spaced baffles as 15 may be placed one below the other in the cylinder 5, Fig. 3 (not shown). Preferably the baffles are arranged as shown in Fig. 4 to direct a cross-blast also on the arc by means of apertures 22, 23. In Fig. 6, the contact 1 is mounted on a member 7 carrying a sleeve 28 to which is fastened a member 30 by means of webs. The member 30 carries the barrier 15 and cylinder 29 in which is a disc 9 making a loose fit with the contact 2 and a smaller disc 33 making a close fit with that contact. Outside 29 is a further cylinder 34, under spring control 12, which is secured to a piston 35 having excess-pressure relief valves 40. When the arc is struck, the piston 35 and cylinder 34 are raised and the fluid within the latter is impelled into chamber 5 and through the hole 16. Two such arrangements may be mounted on insulators in a tank and the contacts 2 mounted on a bridgemember, Fig. 7 (not shown). The Specification as open to inspection under Sect. 91 described and illustrated also two forms of the invention in which the fixed contact is formed by, or located in, the confining walls of the channel, and two forms in which an oilbreaker with movable bridging contact of conventional type has its contacts adjacent an aperture in a cylindrical wall surrounding both breaks, so that a blast of fluid can be passed from outside the wall through each aperture to the inside or vice versa. It also described and illustrated the arrangements forming the subject of Specification 409,099. This subjectmatter does not appear in the Specification as accepted.