Arc spot scanning of tube electrodes in gas-vortex plasmatorches

摘要

The peculiarities of cooling of stationary working hot and cold cathodes are under consideration. Scientific premises of the advisability of the tube electrodes arc-spot scanning are presented. The classification of the scanning methods is given. The assumption has been made that the phenomena of auto-electron emission of electrons in vacuum discharge tubes and in arc chambers of plasmatorches under the pressure equal or above atmospheric are somehow similar. The optimum scanning frequency and achievable values of the end-face tube cathode life-time have been estimated. Owing to the magnetic scanning, the area of the electrode surface, which is swept by the arc spot, increases one order or more, resulting in better cooling and reduced specific erosion. The continuous electrode lifetime becomes several orders longer than it is during the work without scanning.