US1682847A - Electric-arc lamp - Google Patents

Description

Sept. 4, 1928.

I. J. LAVOKSIER ELECTRIC ARC LAMP Filed Oct. 1924 A W 7mm 1w; 0?

Patented Sept. 4, 1928.

UNITED STATES PATENT OFFICE.

IAN JEAN LAVOISIER, OF NEW ORLEANS, LOUISIANA, ASSIGNOR, BY MESNE ASSIGN- MEN'I'S, TO THE BURDIGK CORPORATION, OF MILTON, WISCONSIN, A. CORPORATION OF DELAWARE,

ELECTRIC-ABC LAMP.

My invention relates to electric arc lamps.

It will be explained as applled to a lam particularly adapted for therapeutlc uses a though not limited to this field.

One of the objects of my invention is to provide an improved electric arc lamp.

Another object is to provide an improved electrode for are lamps.

Another object is to provide a method of .10 making highly conductive electrodes composed of materials which are normally highly non-conductive under ordinary temperatures and voltages.

Another object is to provide a highly re- 1 fractory electric arc electrode.

Another object is to provide an are discharge -whose spectral characteristics may be made to closely approximate those of sunlight at high altitudes.

Another object is to provide electrodes for are discharges of various spectral characteristics.

A further object is to provide improved means for effecting the formation of the are discharge between the electrodes.

Other objects and advantages will hereinafter appear.

The accompanying drawing illustrates somewhat diagrammatically one form which my improved lamp may assume.

I have found that intense and hi hly satisfactory arc discharges may be pro need be tween electrodes which contain zirconium and yttrium oxides. At ordinary room temperatures of around 20 to 38 degrees centigrade zirconium and yttrium oxides are highly nonconductive but I have found that these oxides may be combined with other materials and so treated as to provide a substance which may 40 be readily formed into electrodes and have suificient conductivity to produce satisfactory arcs when subjected to normal service voltages at ordinary room temperatures. The arc is readily formed and easily maintained 4!! and its spectral characteristics will very closely approximate those of sunlight at hi h alti tudes. Furthermore, I have found t at by adding other substances the spectral characteristics of the arc discharge may be quite materially varied to meet special requirements of therapeutic and other fields of use.

The method which I have found suitable for providing my improved electrodes is as follows:

Zirconium oxide and yttrium oxide in finely powdered condition are mixed together with a suitable binder, such as hydrogel (zirconium hydroxide), to form a paste. I have found that the zirconium and yttrium oxides when powdered suificiently fine to pass through a screen of 120 mesh will give good results. The proportions of the two oxides which I have found satisfactory are approximately 7 5 to 85 per cent chemically pure zir conium oxide and 25 to 15 per cent chemically pure yttrium oxide. Enough of the binder, such as hydrogel, is added so that the mixture of the three ingredients forms a paste which may be worked or molded into suitable sizes and shapes for the subsequent treatments.

The pasty mixture may then be worked, or compressed in suitable molds, to form electrodes of the desired shape. I have found that for therapeutic use substantially cylindrical electrodes of about diameter give good results. The paste should be sufliciently plastic to permit its being formed into the proper size and shape and yet stiif enough to retain that form during the remainder of the treatment.

The formed electrodes are next dried at ordinar room temperature, such for example, as etween 20 to 38 degrees Centigrade for a suflicient length of time to thoroughly dry the mass. The length of time'required will depend upon the consistenc of the paste and the atmosphere humidity, ut from two to four days will ordinarily sufiice.

After being dried as above described the electrodes are placed in a suitable furnace and the temperature gradually raised, preferably a few degrees an hour, until the mass is dehydrated. Then the temperature is raised more rapidly if desired, until the surface of the electrode is sintered. Ordinarily this sintering temperature will be between 1900 and 2200 degrees centigrade. The proper temperature will be evidenced by the glazing or vitrifying of the electrodes. After the electrodes are thoroughly glazed or vitrified they are ready for use.

If it is impracticable to obtain chemically stant, and possesses ve pure yttrium oxide free from the erbium or terbium groups of metals, the finished electrodes may not be sufliciently conductive at ordinary room tem ratures and service voltages to give g results. However, the pro r conductivity may be obtained by inclusi ng in the p mixture a suflicient quantity of any the following substances :--zirconium carbide, titanium earbide, tungsten carbide, or tantalum carbide, or ferro-alloys of any of these elements. The amount of any of these substances which may be required 'will depend u n the degree of purity of the yttrium oxi e and the conductivity desired in the finished electrode. Ordinarily the amount will be small.

The electrodes produced by the foregoing method are conductive at ordinary room temperatures, such for example, as 20 to 38 degrees centigrade and at ordinary service voltages, such, for example, as 110 to 220 volts. The are produced when the electrodes are subjected to such voltages is intense, conclosely the spectral characteristics of sunlig t.

In order to increase the intensity of the visible rays produced by the are, calcium fluorid or preferably titanium carbide, may be added to the mixture of zirconium and atrium oxides. I prefer titanium carbide cause it is a better conductor of electricity than the other substances.

The percentage of actinic or ultraviolet ray emission from the arc may be increased by adding tungsten, tantalum or molybdenum or their salts to the mixture of zirconium and yttrium oxides.

The percenta of infra-red ray emission may be increase by the addition of thorium, cerium or silicon.

The accompanying drawing shows one form of lamp particularly suited for therautic uses. It has an exhausted or inert as sided bulb 1 forming a closed chamber %or the electrodes. The bulb may be made of glass, quartz or other suitable transparent or translucent material. If an intense emission of ultra-violent rays is desired, the bulb may be made entirely of quartz, although I prefer to provide merely a quartz window 2 at the bottom which may be sealed to a glass side wall b suitable means such as nascent silver chlori e under heat. The upper end of the bulb 1 is sealed in the usual manner and secured to a suitable metallic support and connector 3 of any appropriate type. I have shown a supporting connector having projecting pins 4 for cooperation with bayonet slots in the metal shell 5 of a suitable plug recvigitacle.

ithin bulb 1 there is an insulating support 4 which carries-two conducting electrode supports 6 and 7. Electrode supports 6 and 7 may be formed from stri s of suitable metal such as bronze or steel. upport 7 in particular is made flexible so that, although it is normally biased away from support 6, it may be moved toward the same to bring the electrodes together, as will be hereinafter described. Electrode pencils 8 and 9, formed as hereinbefore described, are secured to supports 6 and 7, respectively, by suitable means such as screw clamps.

Support 7 is provided with an armature 10 which is in a position to be attracted by a small electromagnet 11 rigidly secured to insulating support 4.

Support 6 is connected to the metal connector 3 by a conductor 12 sealed through the walls of bulb 1 and to one terminal of electromagnet 11 by a conductor 13. Support 7 is connected to a lamp contact 14 which is insulated from connector 3 and ada ted to engage a contact 15 of receptacle 5. be other terminal of magnet 11 is connected to a lamp contact 16 which is insulated from contact 14 and connector 3 and is adapted to engage a receptacle contact 17.

One of the service wires 18 is electrically connected to the receptacle shell 3. The other service wire 19 is connected to receptacle contact 16 and, through a suitable switch 20, to a receptacle contact 17 The lamp is operated by closing switch 20 which completes a circuit through electromagnet 11. The energization of electromagnet 11 attracts armature 10, bringin electrodes 8 and 9 into on gement and tlierebv completing a circuit t erethrough. Switch 20 is thereupon opened de-energizing electromagnet 11 and rmitting electrodes 8 and 9 to separate anfi drawing the are therebetween.

I claim 1. An electric arc electrode comprising a dehydrated and lazed mixture of zirconium and yttrium oxi e.

2. An electric arc electrode comprising a dehydrated and glazed mixture containing zirconium and yttrium oxides in approximately the following proportions: zirconium oxide, to yttrium oxide, 25% to 15%.

In testimony whereof I hereunto subscribe my name.

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