US1009291A

US1009291A - Arc-lamp electrode.

Info

Publication number: US1009291A
Application number: US52397709A
Authority: US
Inventors: Georg Egly
Original assignee: Gebrueder Siemens and Co
Current assignee: Gebrueder Siemens and Co
Priority date: 1909-10-22
Filing date: 1909-10-22
Publication date: 1911-11-21
Anticipated expiration: 1928-11-21

Description

G. EGLY.

lARG LAMP BLEGTBODE.

APPLICATION FILED 00T. 22, 1909.

- l1,009,291.r y Ptented N0v.21,1j911.

Be .it known that I, Gaone EGLY, a sub' ,saone EGLY, orrnxrrowfma'fsiiaivg'cnmgng, 'AssIeNon fro snsannn a comrmnror BERLIN, GERMANY. p

ject of the German Emperor, and residing A at Treptow, near Berlin, Germany, have in-A consist of light emitting in vented certain new and useful Improvements in Arc- Lamp Electrodes, of which the following is a c My invention re atesto arc lamp electrodes and a primary obect isto pr'ovlde an eleetrodecontaining p ho-boric acid. be understood arcom electrodes ents, such as compounds of the alkalis, alkaline earths and rare earths, together 'with carbon or carbonaceous material and a binder, the latter being sometimes of carbonaceous material such as tar or sometimes of water glass.'

My invention has for its object by the addition of phospho-boric acid to improve the electrode, not only in its rocess of manufact-ure but also 1n its be avior under the action of the electric current, and also to improve the qualitytand character of the arc and thelight emitted thereby.

Phospho-borlc Aacid has the composition BPO4 and is obtained b the action ofboric acid on 'phosphoric aci For example, if pulverized boric acid be placed into concentrated phosphoric acid a treacly mass is -flrstly obtained in which boric acid and phosphoric acid are contained separately one beside the other. If this viscous mass be evaporated to dryness, an earthy, exceedingly highl refractory mass, phosphoboric acld, is obtained. The same product is also obtained when a mixture of the anhydrids of boric acid and phosphoric acid is heated to redness.

I may employ the phospho-boric acid either in its inished form, or in the form of the mixture of anhydrids, or in the form .of an emulsion of boric acid in concentrated phosphoric acid. In the two last cases the phospho-boric acid is -rst formed in the carbon mass or in the finished electrode.

vAbove all it causes very quiet burning and renders entirely non-injurious any lmpurities which the carbon or tar employed in the manufacture ofthe electrodes contains. It is related in certain respects'in its action to boric acid on the one hand and tophosphoric acid on the other hand, but iswithout the disadvantages of these. For example boric acid and borates, `which are well- "91x01y I' 'i tirati-on..o-'fLtters?iraient.l Appumion mea october as, moa serial ivo. 523,977. "l v -j ification. v

` 3. nnncfrnonns 'Patentel Nov. 21, 1911.

i l Aknown. .quite generally for steadying the arc, are very readily'fusible and favor under -certain circumstances the formation of slag, whereas phospho-boric acid, on the contrary, 1s practically non-fusible. Further, both bor1c acid and phosphoric acid, when added by themselves alone'to the carbon mass, act lvery unfavorably on the waterlass employed for binding the carbon.' T ey cause the water-glass to stien and take from it its lubricity. If phospho-boric acid be employed instead, the water-glass retains its good properties. Phospho-boric acid is consequently very particularly suitable as an admixture for core masses which are to be Vworked up with water-glass.

Phospho-boric acid is distinguished from borates when used as an admixture with rsalts of thealkalis, earth alkalis or rare "`earths\in that it possesses the advantage of regulating vaporization and also concentrates the arc and considerably increases the emission of light.

. A further advantage is afforded by phospho-boric acid as compared with .borates in that electrodes containing phospho-boric acid and provided with light emitting substances burn both -with direct and also with alternating current with lamp tensionsof up tov45 and indeed 50 volts without the arc being ruptured, whereas when carbons' of the same kind containing borates are used the arc ruptures at about 35 volts particularly in the case of alternating current.

Part of one form of my lmproved arc lamp electrode is represented by way of ex-v ample. in vertical sectional elevation in the accompanying drawing wherein a design nates the carbon shell surrounding the core b containing carbon, light emitting substances and phospho-boric acid.

By way of illustrative example of an electrode composition embodying my invention I mention the following composition: fluorspar forty parts, carbon forty parts and phospho-boric acid three arts. These ingredients are mixed in t e usual manner with as much water glass as .willlproduce a moldable mass. v

I claim:

1. An arc lamp electrode containing phos- 3. An arc lamp electrode consisting of al s Q t 1,099,291

shell of carbon surrounding a. core composed name to this specification in the presence of of a, mixture of carbon, light emitting subtwo witnesses. stances `and phospho-boric acid. l 4. An arc lamp electrode consisting of `a i 5 mixture of carbon, a light emitting sub- Witnesses: v

stance, phospho-boris vacid. and Water glass. HENRY HASPER,

' in testimony whereof I have signed my WoLDEm GEORG EGLY.`