US889937A - Electrode for arc-lamps. - Google Patents

Description

No. 889,937. PATENTED JUNE 9, 1908. G. M. LITTLE.

ELECTRODE FOR ARC LAMPS.

APPLICATION FILED MAY 10, 19061 INVENTOR WITNESSES ATTORNEY @H-a 6.15M

UNITED STATES PATENT OFFICE.

GEORGE M. LITTLE, 0F PITTSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIO & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRODE non nae-Limes.

Specification of Letters Patent.

Patented June 9, 1908.

Application filed lay 10,1908. Serial No. 816,181.

To all whom it may concern:

Be it known that I, GEORGE M. LITTLE, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have inventeda new and useful Improvement in Electrodes for Arc-Lamps, of which the following is a specification.

My invention relates to are lamps and articularly to those in which one of the e ectrodes is composed of materials which cause the arc to be luminous.

The object of my invention is to provide an anode for a lam of the character indicated which will ena le ready starting of the lamp under all conditions as well as the production of a steady, uniform light.

' Arc lamps are now frequently provided with com osition electrodes of such charac-' for that t 1e arcs produced are more luminous than those produced between ordinary carbon electrodes and also such that they are ver much less rapidly consumed. An electrode which has been found suitable in practice has been composed of a mixture of magnetic oxid of iron which is a conductor both when hot and when cold and which gives conductivity to the electrode, oxid of titanium which lmparts appropriate color and brilliancy to the arc, and oxid of chromium which steadies the arc and prevents the electrodes from being rapidly consumed, these substances being combined in various and suitable proportions. Other compositions of these metals or of others having similar or suitable pro erties may also be emloyed. Such an 'e ectrode has usually een employed as the cathode in combination with a cop er positive electrode which is but very slow y consumed. In operation of the lam however, a slag forms on the anode that 1s composed of the oxid of copper, a very poor conductor when cold, which revents electrical contact between the ecotrodes and consequently interferes with ready starting of the lamp after it has once been in use. For this reason it has been proposed to employ iron for the positive electrode or some other metal, the oxid of which is a conductor. Iron, however, is more rapidly consumed than copper and what has been termed pooling frequently occurs when it is employed; that is, the arc plays u on a comparatively small portion of the en of the composition electrode until the surface becomes hollowed and a depressed ool of the molten oxids forms, upon which t e are moves rapidly, resulting in flickering of the light.

I have, found that the advanta es pertainin to both copper and iron, wien employe as the positive electrodes in lamps of the character indicated, may be secured and the disadvantages of 0th be obviated or reduced by providing a positive electrode that iscomposed of both of these metals in the roper relations and proportions. I

F1gure 1 of the accompanying drawing is an isometric view of the electrodes of an arc lamp, one of which is constructed in accordance with .my invention, and Figs. 2 and 3 are similar views of modifications. I

As here shown in Fig. 1, the anode 1 comprises a rod or cylinder of iron or other metal, the fused oxid of which is a conductor when cold,-havin longitudinal radial slots or recesses'in which strips 2 of another metal, such as copper, are located. While I prefer that the main ortion of the anode be composed of iron and that the copper strips be placed in the radial slots, a reversal of this arrangement -may be employed, if desired. Other metals than cop er and iron may also be employed without e arting from the spirit of the invention so ong as the fused oxld of one of the metals is a conductor when cold while the fused oxid of the other may or may not be a non-conductor when cold. For instance,

' silver may be conveniently employed instead of iron since the fused oxid thereof is a conductor. The electrode may also be formed, if desired, as shown in Fig. 2 in which cylinders 3, 4, 5, 6 and 7 that are composed alternately of copper and iron placed one within another, or t may be formed of plane strips or 'laminations 8 and 9 of copper and iron, as indicated in Fig. 3, or in any other suitable manner, it bein preferable, however, in all cases, to ma e the outer layer or the larger portion of the superficial area that is not exposed to the arc of iron. With such an electrode, I have found that pooling does not occur and that consequently a steady are results. The rate of consumption of the electrode is also considerabl less than that of iron alone, and it has been ound that, if the larger portion of the exposed area is composed 0 iron, the life of the electrode may even be greater than that of copper alone, the iron serving as mechanical means for preventing-scaling of the oxid that forms upon the surfaces of the copper unexposed to the are, thereby preventing continued oxidation of the copper. A

I claim as my invention:

1. An are lamp electrode composed of copper and iron.

2. An arc lamp electrode com risin a rod of iron and strips of copper embe ded t erein.

3. An arc lamp electrode comprising a lurality of layers composed alternately of iron and copper.

' Anarc lamp electrode comprising a plurahty of layers composed alternately of a metal the fused oxid of which is a conductor and a metal the fused oxid of which is a nonconductor when cold. v

In testimony whereof, I have hereunto subscribed my name this lst day of May, 1906.

GEORGE M. LITTLE.

Witnesses:

., OTTO S. SOHAIRER,

BIRNEY HINES.

Images