GB507757A - Improvements relating to apparatus employing an electric arc - Google Patents

Abstract

507,757. Electric heating. ALLGEMEINE ELEKTRICITATS-GES. Nov. 16, 1937, No. 31551. Convention date, Nov. 16, 1936. [Class; 39 (iii)] [Also in Groups XL and XXII] Electrodes for arc converters, electric welding, &c. consist of an alloy of two, or more metals and are operated in a mixture of gases one of which attacks one of the constituents of the alloy to form a thin coating on the surface of the electrode, which is stated to reduce disintegration of the electrode and improve the burning of the arc. As an example the electrode may consist of a eutectic alloy of copper and silver burning in a mixture containing oxygen; it is stated that the silver acts as an oxygen carrier and produces a coating of separate layers of the two oxides of copper. The proportion of oxygen in the gas is preferably between 1 per cent and 3 per cent ; if nitrogen with a greater percentage of oxygen is employed, the gas should be blown off to prevent the accumulation of oxides of nitrogen. A larger proportion of oxygen may also be employed if the electrode contains a higher proportion of silver. A smaller proportion of oxygen may be employed along with some substance which liberates oxygen, or the oxygen may be introduced in the form of the oxides of carbon. Other suitable alloys comprise silver or gold with manganese, alkaline earth metals, or rare earth metals,