GB502443A - Electric circuit breaker having arc-extinguishing arrangements - Google Patents

Abstract

502,443. Fluid -- blast switches. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. April 19, 1938, No. 11753. Convention date, April 16, 1937. [Class 38 (v)] A circuit - breaker with a differential piston causing a flow of extinguishing fluid through an opening in the piston traversed by the movable contact, is provided with an additional device for extinguishing smallcurrent arcs and consisting of a cylinder and a piston which is movable in the cylinder and actuated by the breaker - operating mechanism. The differential piston 21 works in a cylinder 22 and is cup-shaped to receive the additional device 9, 12, and has slits 27 and channels 28 leading to the space 24 outside the piston. When the movable contact 2 is raised so that its tip has opened the slits 27, the piston is raised by the arc-pressure, thereby forcing a blast of extinguishing medium from the space 24, through the channels 28 and slits 27 on to the arc. When the contact clears opening 30, the blast is directed upwards into the space above the piston-bottom 25. On further movement of the contact 2, a shoulder 17 engages a shoulder on the upper end of the piston 12, which is raised to squeeze fluid from inside the cylinder 9, through openings 15 on to the contact tip, which is just above the opening 14 in wall 13, and also through the bore 16 in the contact 2. In moving downwards, the piston 12 creates a vacuum in cylinder 9 whereby the latter is refilled past the lightlyloaded valve or packing 11. The Specification as open to inspection under Sect. 91 describes also the arrangement according to which the additional piston and cylinder are used alone, the piston being raised and lowered by the engagement of a rim on the contact 2 with shoulders on the upper part of the piston. This subjectmatter does not appear in the Specification as accepted.