GB644947A - Improvements in fluid-blast electrical switches - Google Patents

Abstract

644,947. Fluid-blast switches. CZECHOSLOVAK METAL & ENGINEERING WORKS. NATIONAL CORPORATION, and HOUST, F. May 14 1948, No. 13342. Convention date, May 16, 1947. [Class 38(v)] A fluid-blast switch in which the arc-extinguishing blast is provided by a supply of compressed air, by the gases evolved by the decomposition of insulating material, or by gases evolved by oil, has a rotary blade system to which rotation is imparted by the gases, the blade system being effective to assist in deionizing the gases and to assist in the application of fresh quenching fluid to the arc. In the air-blast switch of Figs. 1 and 2 an axially-moving contact 4 co-operates with a fixed contact 1, both contacts being provided with arcing horns 3 disposed in a slot 7 in the insulating tube 6 surrounding the contacts. The blade system 8 is fitted around the tube 6 and has its blades arranged at an angle to the plane of the slot 7, the blades being subdivided and supported by partitions 9. When the switch is opened, an arc is drawn between the horns 3 and the gases caused by or flowing through the arc impinge on the blades 8 causing them to rotate. The arc is disrupted at the extremities of the horns 3 by the blades, which also bring cells (i.e. the spaces between the blades) of un-ionized fluid opposite the arc horns. Blast-gas may be admitted to the interior of the tube 6 by means of pipes 14, 15 and the contact 4 if hollow, and arrangements such as slot 17, may be provided for scavenging the blades by means of air under pressure. The blade system 8 may comprise several co-axial or superimposed runner wheels with blades which may have different admission angles, and the partitions 9 may be of conducting material. Figs. 3,and 4 (not shown) illustrate the application of the invention to an oil blast circuitbreaker.