GB534979A - Improvements in or relating to liquid immersed electric circuit interrupters - Google Patents

Abstract

534,979. Liquid-blast switches; switch cases WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Sept. 21, 1939, No. 26355. Convention date, Oct. 27, 1938. [Class 38 (v)] The arc-chamber is arranged to be flushed with clean liquid by means actuated by the contact-actuating means in response to the pressure within the chamber having subsided. A tubular insulating strain member is housed in a tubular porcelain insulator surmounted by a two-part cover, the parts being separable to relieve excess pressures in the entire liquid-filled housing in the manner set out in Specification 534,936, [Group XVII]. In Fig. 2, each of a pair of seriesconnected interrupting elements 31, 33, contains an arc-chamber 48 with a corrugated surface formed by discs 45, 47 arranged in a stack in an insulating tube 41 having metal collars 43 screwed on to each end. The elements are separated by a member 35, and are mounted on the housing by means of four arms 39 on a member 37. The fixed contact structure of each element comprises four fingers 51 carried on a support 53 above the upper collar 43 and connected by flexible elements 57 with the member 37 in the case of the upper element and with a conducting part 71 on the central operating member 59 in the case of the lower element. The fingers are adapted to be engaged by contacts 63 on contact rings 61 on member 59, the contact 63 on the left being adapted to separate last from its finger to draw the arc. Above each ring 61 is a stack of insulating washers 65, 67 of alternately different diameter arranged to form a piston to displace liquid upwards longitudinally of the arc and into the expansion chamber 49. The lower ring 61 engages a metal cap 73 which engages a plunger to which the closing mechanism is connected, Fig. 1 (not shown). To open the circuit, a battery of compression springs 87 is located between upper and lower plates 89, 91. The member 59 is secured to plate 91 and is guided on rods 115 screwed into member 37, and the plate 89 bears on a stop plate 117 fast on the rods 115. The member 37 is covered by a plate 139 having a collar 141 and rods 115 on which slides a cylinder 143, the side walls 145 of which slide on the circumference of the plate 139. Normally annular chamber 151 is provided by springs 149 on rods 115 whereby oil enters by means of apertures 155 leading to an annular groove 153 in which is an annular valve 157 slidable on pins 159. This chamber 151 communicates through apertures 165, 167 in plate 139 and member 37, respectively, past non-return valves 169, and through pipes 161, 163 and passages 173 in the lower caps 43, into the respective arc chambers 48. At the end of the downstroke of springs 87, plate 91 engages the upper ends of bolts 179, so compressing springs 181 in tubular extensions of cylinder 143. When the pressure in the arc chambers 48 subsides, the springs 181 drive cylinder 143 downwards and force clean liquid into the chambers, the springs 149 restoring the cylinder 143 when the switch is reclosed. Resistance to the downward movement of plate 91 is reduced by perforating the latter and the opening shock is absorbed by a stop plate 185 and buffer plate 187 controlled by a weak spring 189. The layer of liquid between 185, 187 is displaced and provides the buffer action, but with an imperforate plate 91 the plate 187 can be omitted. The Specification as open to inspection under Sect. 91, described also the matter appearing in the divided application 537,069. This subjectmatter does not appear in the Specification as accepted.