GB191125916A - Improvements in and connected with Electrodes for Arc Lamps. - Google Patents

Abstract

25,916. Beck, H. Nov. 20. Arc lamps.-A positive electrode for searchlights and for flash and other lamps contains flame-arc material in the form of a core or otherwise, and is of smaller diameter than the crater which would be produced by the same current in a carbon not containing such materials. High luminous efficiency is thus obtained. The negative carbon may be of smaller diameter than the positive one, and may have a coating of metal to increase its conductivity, and a core of material such as graphite, tungsten, or the like, more refractory than carbon, so that a point is formed in burning. The electrodes may have longitudinal ribs, and are cooled and protected by gases or vapours such as coal gas, carbon dioxide, nitrogen, hydrogen, acetylene, benzine, ether, alcohol, or naphthalene; these confine the arc to the end of the positive electrode. Such gases may be supplied through an electrode itself, or through an annular space d in a metal sleeve c surrounding an electrode, or throngh a number of nozzles opening from a chamber in such a sleeve. If sufficient pressure is used, the same jet or jets may protect both electrodes. A flat nozzle may send a current of gas at right-angles to an electrode near its end. Liquids may be fed through a tube surrounded by a series heating- resistance, or may be dropped on to an electrode or on to a plate near the arc. Solids such as naphthalene may be dropped on to a similar plate or formed into a coating for an electrode. The electrodes may be rotated slowly by hand or otherwise. The metal sleeve c may have cooling-ribs or a water-jacket, and may supply current to the electrode throngh a pair of spring-pressed pins.