Patent GB-398890-A (GB)
Title: Improvements in or relating to metal-clad electric switchgear
IPC: H02B13/035
Filed: 1932-03-24
Abstract: 398,890. Switchgear structures. REYROLLE & CO., Ltd., A., Hebburn-on- Tyne, and ALLAN, A., Cragside, Ashleigh Grove, Tynemouth. March 24, 1932, No. 8769. [Class 38 (v).] Oil switches; fluid actuation.-In metal-clad switchgear comprising a chamber containing a bus-bar or other conductor immersed in a liquid and a movable conductor which, in its operative position, projects through an orifice in the wall of the chamber and makes contact with the bus-bar or other conductor therein, a sealing'device is provided by which the orifice can be sealed in a liquid-tight manner when the movable conductor has been withdrawn from its operative position. The movements of the movable conductor may be effected by fluid pressure, as claimed in Specification 398,889, and the movable conductor may be so mounted, as claimed in Specification 398,891, that it can be withdrawn towards or into a tank containing the apparatus to be connected to the bus-bar. The description in respect of Figs. 1-12 and 23-25 (not shown), is identical with that contained in Specification 398,889. Figs. 14 and 16 show an arrangement for three-phase switchgear for use on the lower voltages, in which the three phases of the circuit-breaker are all contained in a single oil-tank 360 mounted on wheels beneath a framework 361 carrying an upper chamber 362 for the external circuit connections. The movable conductors are mounted in six tubular structures 364 arranged in two rows on the cover of the tank 360, the three tubular structures in each row being sealed off, when the conductors have been withdrawn towards the tank, by three sluice valves 371, 372, 373 mounted in a single valve chest and operated by a hand-wheel 366. These valves may be mounted integrally with each other and driven by a screw-threaded shaft carrying the handwheel, or, as shown in Fig. 16, the valves may be connected together through pull rods and compression springs to ensure correct seating. The circuit-breaker controls the connections from a feeder circuit 380 to a three-phase power transformer in a tank 381, the connections from the contacts in the chamber 362 to the transformer windings being controlled by three insulated conductors 382 mounted in tubular structures 383 connected by flexible bellows 384 to a valve chest 385 containing three sluice valves. Instead of employing sluice valves for the sealing members, the latter may be in the form of a plug 410, Fig. 17, mounted on a sleeve 413 on a shaft 414 in the bus-bar chamber 400, the plug being moved to close the orifice of the bus-bar chamber by rotating the shaft. In a modified arrangement, the plug is operated through levers and gearing. Fig. 17 also shows a method of securing the flexible bellows 390 to the bus-bar or other chamber, by means of an arm 392 which is pressed against a flange 391 on the bellows by a toggle mechanism consisting of levers 394, 395. In a further form of sealing device, Fig. 19 (not shown), the sealing plug is carried by the movable conductor itself. In a further arrangement, Fig. 21, the movable conductors 453 are fixed in position on a hood 451 attached to the circuit-breaker tank 450, isolation being effected by bodily moving the tank. The hood is connected to valve chests 462 on the bus-bar and feeder chambers 460, 461 by bellows 454 of sufficient elasticity to permit movement of the circuit-breaker for isolating purposes without detaching the bellows. In another arrangement, Fig. 22, the movable insulated conductor 500 is surrounded by a metal sleeve 503 formed with a toothed rack 504 engaging a pinion 492 ; in this arrangement the movable conductor is operated mechanically, by rotating the pinion, instead of hydraulically. In Fig. 26 is shown the application of the invention to an arrangement of the kind described in Specification 353,408, in which the movable conductor 660 is withdrawn into the chamber to be sealed. In this arrangement, hollow insulators 650, 681 project respectively into the circuit-breaker tank 651 and bus-bar chamber 680, the bus-bar 686 being adapted to be connected to a contact 682 in the insulator 681 by an isolating switch 684. The movable conductor 660, which is operated by fluid pressure through ducts 672, carries a sealing plug 666, which seals the compartment formed by the insulator 681 and trunk 670 when the conductor has been withdrawn into the isolating position. In this position the upper contact 665 of the conductor engages an earthing contact 688.