US1964832A - Electrode for arc furnaces - Google Patents

Description

July 3, 1934.

P. SOULARY ELECTRODE FOR ARC FURNACE IS Filed NOV. 25. 1932 Inventor Elie/ fie dazzle/ 7 By w Attorney supplied to the are.

Patented July 3, 1934 UNl'lED STAT ELECTRODE .FOB ARC FURNACES Pierre Soulary, Le Perray, France, assignor to LAir Liquide, Societe Anonyme Pour LEtude et LExploitation Des Procedes Georges Claude,

Paris, France Application November 25, 1932, Serial No. 644,251 In Great Britain November 26, 1931 4 Claims. (01. 204-31) The present invention relates to an electrode used in furnaces, in which a fluid having a great dielectric strength, such as liquid hydrocarbon, is submitted to a fixed or rotary arc, or to disruptive discharges. This electrode is opposite to, and at a little distance from, a hollow electrode, having substantially the same axis and through the interior of which the fluid to be treated is In proportion of their wear, the electrodes are fed one to the other in order to maintain the small suitable length of the arc, bound to the dielectric strength of the fluid to be treated.

When the electrode, of which the present in-# vention is an improvement, is solid, it is worn in such a manner that a larger and larger projec tion is progressively formed in its central part, owing to the more rapid wear of the adjacent peripheral parts, which are opposite to the solid active part of the hollow electrode. Therefore, when the two electrodes are fed together to maintain the are at the small desired length, this projecting part, even if small, engages in the fluid supply conduit of the hollow electrode and may provoke short-circuits, if it comes into contact with this hollow electrode, the wear of which is therefore made irregular.

The present inventionhas particularly for its object to remedy these drawbacks; it consists in using, as an electrode situated substantially opposite to the hollow electrode, an electrode (that will be also thereafter called counter-electrode) that is provided with .a central cavity extending from its active end for a part of its length towards its *closed end and in which the sections perpendicular to. its'axis,;along its hollow part, made 'ati-difierent distances from its active end are identical to the section's'of the opposite electrode perpendicular to its axisl made at the same distances from the active end of said electrode.

This counter-electrode is constituted, for example, by a cylindrical rod of carbon bored for a certain part of its length or even by a cylindrical tube one of the'extremities of which is provided with a cap, so as to close the interior cavity of .this tube.

Preferably the counter-electrode terminates in a flat face perpendicular to its axis and the hollow electrode terminates also in a flat face perpendicular to its axis.

The counter-electrode and the hollow electrode constitute a set of electrodes in which the active surfaces from which the arc jumps at the extremity of. each electrode are, at each moment of the working of the furnace, equal and parallel together and perpendicular to the axis of the electrodes. The are jumps therefore in a uniform manner between the two electrodes and these are equally worn away. Consequently, in spite of the wear of the electrodes, their active surfaces 69 remain substantially parallel and the steadiness of the arc is obtained. This parallelism of the active surfaces of the electrodes affords a particularly important advantage in the case where liquid hydrocarbons are treated by the are, for c5 the length of the arc is only' a few millimetres.

An embodiment of the invention is diagrammatically illustrated, by way of an example, in the accompanying drawing.

In this drawing. A denotes a cylindrical tubular 79 rod through the interior of which the liquid to be treated is supplied to the arc which jumps between this electrode A and an opposite electrode B. This electrode B is a cylindrical rod, coaxial with the electrode A and having the same diameter; it is provided with a cylindrical cavity 6, which extends only for a part of its length from its active end and the diameter of this cavity is equal to the inner diameter of the tubular electrode A. The electrodes A and Bterminate S0 in a fiat annular face, which is perpendicularto their common axis, and constitutes the active part of these electrodes.

Instead of using the counter-electrode in its hollow form, its cavity may be filled, before the electrode being used, by a suitable substance, able to be progressively brought away under the influence of the heat of the are (or of the current of fluid supplied through the hollow opposite electrode) simultaneously withthe wear of the active part of this counter-electrode: for example, use may be made of pitch for this purpose.

When liquid hydrocarbons are to be treated by the arc, it isnot necessary to previously fill the cavity of the counter-electrode: this cavity, 9 becomes automatically filled, after the arc is struck, with a pasty mass constituted by a mixtureeof the liquid hydrocarbon submitted to the treatmentby the arc and of the carbon formed by the decomposition of this hydrocarbon; this pasty mass is also worn away progressively at the same time as the active part of the counterelectrode is worn.

Although the wear of theelectrodes generally takes place regularly over their whole active face,,- it is possible, with a view to make such wear more uniform, to impart to one of the electrodes (or to both electrodes) an axial rotary movement, the current supply being efiected by suitable contact brushes and rings: Further the electrodes may be fixed and the arc could be submitted to the action of a magnetic field such as would impart to the are a rotary movement around the axis of the electrodes.

What I claim is-- 1. Ina set of electrodes for furnaces in which a fiuid having a great dielectric strength is submitted to an electric treatment, a hollow electrode through the interior of which the said fluid is supplied to the arc, a counter-electrode situated substantially opposite to the first electrode and at a small distance from said electrode, a central cavity in said counter-electrode extending from its active end along a substantially long part of said counter-electrode, a solid part at the rear end of said electrode closing the said cavity, the sections of the said counter-electrode, perpendicular to its axis, made at different distances from its active end along its hollow part being identical to the sections of the opposite electrode, perpendicular to its axis, made at the same'distances from the active end of said electrode.

2. In a set of electrodes for furnaces in which a fluid having a great dielectric strength is submitted to an electric treatment, a cylindrical electrode, a central cylindrical channel extending along the entire length of said electrode and through which the said fluid is supplied to the arc, a cylindrical counter-electrode situated at a small distance from the first electrode and with its axis in alignment with the axis of said electrode, said counter-electrode having the same transversal shape as the opposite electrode, a central cylindrical cavity in said counter-electrode extending from its active end along a substantially long part of said counter-electrode, said cavity having the same transversal shape as the channel in the first electrode, and a solid part at the rear endof said counter-electrode closing said cavity.

3. In a set of electrodes for furnaces in which a fiuid having a great dielectric strength is submitted to an electric treatment, a cylindrical electrode, a central cylindrical channel extending along the entire length of said electrode and through which the said fluid is supplied to the arc, said cylindrical electrode terminating in a flat face perpendicular to its axis, a cylindrical counter-electrode situated at a small distance from the first electrode and with its axis in alignment with the axis of said electrode, said counterelectrode having the same transversal shape as the opposite electrode, and terminating in a fiat face parallel to the end face of the first electrode, a central cylindrical cavity in said counterelectrode extending from its active end along a substantially long part of said counter-electrode, said cavity having the same transversal shape as the channel in the first electrode, and a solid part at the rear end of said counter-electrode closing' said cavity. v

4. In a set of electrodes for furnaces in which a fiuid having a great dielectric strength is submitted to an electric treatment, a hollow electrode through the interior of which the said fluid is supplied to the arc, a counter-electrode situated substantially opposite to the first electrode and ata small distance from said electrode, a central cavity in said counter-electrode extending from its active end along a substantially long part of said counter-electrode, a substance capable of being worn away in proportion to the wear of said counter-electrode filling the said central cavity, a solid part at the rear end of said electrode closing the said cavity, the sections of the said counterelectrode, perpendicular to its axis, made at diffcrent distances from its active end along its hollow part being identical to the sections of the opposite electrode, perpendicular to its axis, made at the same distances from the active end of said electrode.

PIERRE SOIJ'LARY.

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