GB209053A - Improvements in and relating to relief valves - Google Patents

Abstract

209,053. Metropolitan-Vickers Electrical Co., Ltd., (Assignees of Hill, L. H.). Dec. 23, 1922, [Convention date]. Void [Published under Sect. 91 of the Act]. Boxes and cases.-A liquid seal device for relieving both pressure and vacuum, and particularly applicable for use with oil-immersed electrical apparatus such as contact breakers, comprises a chamber 5 connected by a pipe 7 to a vessel 3 containing a deoxidizing chamber which in turn is connected by a pipe 2 to the space above the oil in the electrical apparatus. A vent pipe 8 is normally sealed by mercury in the chamber 5 and discharges into a trap 9 having a vent 10 to atmosphere and a pipe connection 11 to the chamber 5 for returning any mercury carried over. In the event of the oil expanding inert gas passes through pipes 2, 7 and acts on the surface of the liquid, eventually displacing it below the entrance to the pipe 8 to permit the excess pressure to escape. When the internal pressure is below atmospheric, air is admitted as soon as the drop of pressure is sufficient to empty the pipe 8. In a modification the trap 9 is omitted and in a further modification adapted to operate with the same pressure difference in both directions has both inlet and outlet fitted with return pipes.