Patent GB-409142-A (GB)
Title: Improvements in and relating to arc quenching circuit breaking apparatus for alternating current
IPC: H01H33/70
Filed: 1933-05-24
Abstract: 409,142. High - tension switches. SIEMENS - SCHUCKERTWERKE AKT.- GES., Siemensstadt, Berlin. May 24, 1933, Nos. 15005, 15006, 15007, and 15008. Convention dates, May 24, 1932, June 18, 1932, April 29, 1933, and May 4, 1933. [Class 38 (v).] Pneumatic blow-outs ; arc-rupturing devices. -An a.c. circuit-breaker or fuse comprises a tubular channel formed in a body which is formed of or covered by insulating material, and in which channel the arc is produced or is arranged to extend so that it is closely surrounded about its axis by the walls of the channel, and means for introducing an extinguishing medium under pressure into the channel at a point which is between and removed from the two ends thereof and in a transverse direction to the axis of the channel and the arc, and openings of the channel which open directly to atmosphere and are so arranged that the medium flows from the point of introduction in the longitudinal direction of the arc. The medium may be gas or vapour, or liquid, such as atomized liquid, or combinations of these may be employed, a suitable liquid being water or carbon tetrachloride and a suitable gas being air or carbon dioxide. The material forming the sleeve is preferably of oil-saturated wood, but others are referred to, and the lining of the sleeve is preferably arranged to have a film of cooling water maintained over it. The medium may be released either just as, or before, the arc is formed, the latter arrangement being preferred since the flow of medium is less likely to be held up by the arc-pressure. Further, the flow is arranged to take place at a point such that at the commencement of interruption of the circuit it is in the opposite direction to that in which the arc is drawn. Fig. 1 shows a fuse f in a channel d formed in a body c, into which channel the blast-nozzle e leads. By replacing the fuse by a movable contact closely fitting the channel and engaging b as a contact, an elementary form of switch is obtained. Fig. 4 shows a form in which, after the movable contact a has been withdrawn to the left from the fixed contact b, a spring i draws down a barrier h into the position originally filled by the contact a thus reducing considerably the cross-section of the channel d, and hence confining the arc. In Fig. 7 the sleeve 20 to which the supply pipe 22 is attached is located away from the fixed contact 23 and loosely surrounds the moving contact 24 so that medium can flow in the direction of arrow 26 against the direction of arc-extension. When the arc gets inside the sleeve it is cut by the jet and extinguished. Fig. 8 shows a form in which the sleeve comprises flared nozzles 30, 31 with the inlet 32 at the point of junction, 33, 35 being the fixed and movable contact, respectively. In the Specification as open to inspection under Sect. 91 there is also a modification of this last form, in which a hollow fixed electrode, into which the inlet is led is placed in the axial centre of the nozzles, and two movable electrodes enter the flared nozzles and engage the fixed electrode on opposite sides. Several blast-nozzles may be employed. This subject-matter does not appear in the Specification as accepted.