Patent GB-498581-A (GB)
Title: Improvements in or relating to electric circuit interrupters of the liquid-immersed type
IPC: H01H33/92
Filed: 1938-03-21
Abstract: 498,581. Liquid - blast switches. WESTINGHOUSE ELECTRIC & MANUFACTURING CO. March 21, 1938, No. 8657. Convention date, May 25, 1937. [Class 38 (v)] A circuit-interrupter of the liquid-immersed type having separable contacts for drawing an arc within a liquid-filled arc passage of an arcextinguishing structure and means for moving the are within the passage, is provided with means for moving additional quantities of liquid through the arc in a direction opposite to the arc movement. The general lay-out is shown in Fig. 1 as comprising a pair of arcextinguishing units 13 in insulating strain cylinders 15 secured to each end plate 11 of a housing 7, which contains actuating means 9 for simultaneously separating the series-connected contacts in the units 13 and is mounted on an insulator 3 on a base 1. A resilient metal expansion member 27 is located between an end-plate 19 and a porcelain or other weatherproof shield 25 on each side of housing 7. The two units 13 are similar in construction and each comprises a stack of insulating plates clamped together and slotted at 61 to form an arc-passage 62 of the general cross-section shown in Fig. 9, having a relatively wide part 67 in which the movable contact 103 reciprocates, and a narrow part 69 into which the arc is moved by parts 45 of magnetic material forming with insulating parts 43 the plates 41. Certain of the plates are formed with slots having indentations which form pockets for trapping insulating liquid in the neighbourhood of the arc as it moves across the passage 62. At the end adjacent the fixed contact 87 and arc-horn 99, plates 47, 51 are formed at 49, 53 with open slots leading out of the passage 62. Four apertures 33 in the plates receive tubular guides in which are tie rods 77 for securing the structure and its metal head-plate 75 to the end-plate 11. A further aperture is formed in each plate, as at 105 in Fig. 9, to receive an insulating tube 107 in which the piston 111 and rod 113 reciprocate in the opposite sense to the contact 103. The tube 107 is cut away at 109, Fig. 2, so as to allow liquid to be pumped by the piston 111 into the arc-passage and facilitate deionization of arcs which are not large enough to be moved by the magnetic plates 45 into contact with the liquid in the pockets in the narrow part 69 of the passage 62. At the end of its movement, piston 111 opens a valve 117, and a further valve 125 normally covering holes in the headplate 75 on either side of the are-horn 99 is provided to relieve excessive pressures in the enclosure. Each of the piston-rods 113, 113<1>, Fig. 19, is screwed at 141 into the axiallyaligned movable contact rods 103<1>, 103, respectively, of the opposite unit 13, and the two sets of rods are moved together by counterclockwise rotation of a shaft 145, Fig. 1, which is connected by arm 149 and rod 151 to the crank arm 153 of contact 103 and rod 113<1>, and by arm 251 to the crank arm corresponding to 153 of contact 103<1> and rod 113. Fig. 19 shows the arm 153 and mechanism of the contact 103 in the closed position, the mechanism of contact 103<1> being the inverted image of that shown in Fig. 19. Arms 153, 157 are part of a member 155 pivoted at 159, and arm 157 is pivoted at 165 to a pair of links 167 which are pivoted at 169 to an arm 171. A guide arm 181 is also pivoted at 169 and at 183 to housing 7. The arm 171 is pivoted at 173 to the contact 103, and provided with a pin 175 slidable in slots 177 in a pair of brackets 179 secured to the housing 7. The pivots 173 are interconnected by a further linkage for balancing the reactive forces between the contacts and piston-rods, Fig. 23 (not shown). Specifications 372,284 and 401,166 are referred to.