US1643810A - Gas-filled incandescent lamp and getter therefor - Google Patents

Description

Patented Sept. 21,1927.

UNITED STATES IIPIATENT OFFICE.

DANIEL SNYDER GUSTIN, OF NEWARK, NEW JERSEY, ASSIGNOR TO WESTINGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

GAS-FILLED INCANDESCENT LAMP AND GETTER THEREFOR.

No Drawing.

This invention relates to incandescent electric lamps and more particularly to getters for such lamps.

An object of my invention is the production of a getter especially adapted for gasfilled incandescent lamps and of such a character that the exhaust operations thereof may be sim )lified.

Another ob ect of my invention is the preparation of a getter for application to the filaments in gas-filled incandescent lamps in the form of a solution.

A further object of my invention is the employment of certain organic compounds as getters in gas-filled incandescent lamps,

whereby it is unnecessary to use a hot-exhaust, because of the sensitivity of such getters.

A still further object of my invention is the manufacture of gas-filled incandescent electric lamps, upon the filaments of which is gettered benzidine, a solution thereof or its equivalent.

Other objects and advantages of the invention will become apparent upon reading the following description.

In the manufacture of incandescent electric lamps, it has been considered practically essential to heat the bulbs thereof, While being exhausted, to free them substantially from moisture and occluded gases.

IVhat is termed cold-exhaust that is, the omission to heat the bulb during the exhausting operation, has been tried without obtaining the desired results, when using previous forms of getters or materials for cleaning-up or rendering harmless certain impurities in the gaseous filling of gas-filled incandescent lamps, for example, moisture,

4 oxygenand nitrogen. In the past it has also been customary, if not essential, to apply the getters used to the filamentary material in the form of a. suspension or as solids. This is more or less undesirable because it is difiicult to apply the getter by such a manner in a uniform coating on the filament.

According to my invention, I have prepared a getter, or substance for improving the operation of gas-filled incandescent lamps especially, which may be applied to the filament thereof in solid form or as a solution in either alcohol, water or other solvent and which is so active for cleaning Application filed May 16,

up deleterious gases and vapors in such lamps that the heating of the bulbs thereof during exhaust may be dispensed with. Likewise, extreme purification of the gas used for filling the lamps is unnecessary, because the getter exerts a strong purifying action thereon. Briefly, my getter in its preferred form, comprises a solution of benzidine or .di para diamino diphenyl (N H,),( C l-I and preferably, but not necessarily, in alcoholic solution, because it is more soluble in alcohol and if such a solution is used it will dry more readily after application to the filament. Although the application directed to the filament as a solution is preferred, I may find it desirable to introduce it in the form of a vapor with the gaseous filling. i

My invention will better be understood by the following more detailed description thereof.

I preferably prepare my getter by dissolving benzidine in alcohol so as to make about a 2% solution thereof. The filamentary material, which is preferably of the concentrated or coil type, after mounting in the usual manner, may be dipped in the solution or if desired, may be dipped, sprayed or otherwise coated with the solution before mounting. The mounted filament may then be sealed into the. lamp bulb in the usual manner, the lamp exhausted, either hot .or cold, as it has been found that good results are obtained by this method using a cold-exhaust, although if for any reason it is desired to retain the hot exhaust, the same is not detrimental "when using my getter.

After exhaustion, the bulb is preferably flushed with nitrogen and if desired that the final gas filling be argon or other inert gas, the nitrogen may then be pumped out and replaced by a filling of argon, at the desired pressure, after which, the lamp may be tipped off. The filament is flashed, preferably at a White heat or temperature slightly above normal operating temperature which is above that at which tungsten carbide decomposes, to avoid making the filament brittle.

On flashing the filament gettered with benzidine, it was found that, even though a cold exhaust was employed, lamps of very good exhausting such lamps hot according to pre-' vious practice. When initially liflting or flashing lamps the filaments of which were gettered with benzidine fumes were noticeable and it is though that the benzidine is decomposed by such treatment, forming unsaturated compounds which have a great aflinity for other substances, especially impurities on argon or other inert gas used for filling gas-filled lamps, although I do not wish to be restricted by any theory of operation of my getter.

' When using such a getter while employing a hot exhaust, it was found that no fuming occurred upon initial'flashing, probably indicating that the getter, or part of it, was

volatilized oil during the exhausting opera-' tion. The lainps were of good quality however, showing that it is not necessary that the getter be actually on the filament to accomplish the desired result and indicating that it may be introduced with the gas filling, if desired. In fact, naphthalene, (2 11,, which is a compound similar to benzidine, has been used successfully in this manner. Argon was passed through a. tube containing naphthalene and then used for filling lamps.

Lamps gettered with benzidine .were bump-tested after seasoning and found to be about normal for their type of lamp. Comparative tests show that lamps with benzidinc getters were equal to or slightly better than thwe made by the regular process, with respect to blackening of the bulb.

Although benzidine has been mentioned as the preferred material for a getter, accord ing to my invention, I do not wish to be restrlcted thereto as various other materials of the same character, for example, cyclic compounds, unsaturated carbon compounds and those which are either" unsaturated or from which unsaturated compounds res t on heating, may he used. All such compounds preferably should contain little or no oxygen or oxidizing material. Such materials include diphenyl and higher homologues thereof. together with amino compounds and their deriva ives, isomers and homologues. A few specific examples of such compounds are as follows: crystal violet C G QW JQ) 5, ip l 5 5) diphenyl-imide or carbazole {C HQ KH. or-

-tho-amino-diphenyl NHOC HflI- F acetylene C H anthracene (C H (CH) together with their isomers, homologues and derivatives.

Although I have described what is now considered a preferred emiiodiment of my invention, it is to be understcod that the same is merely illustrative and that I wish to be restricted only by the spirit and scope of the appended claims,

oeasro What is claimed is:

1. An incandescent electric lamp of the gas-filled type containing an oxygen-free, organic getter.

2. An incandescent electric lamp of the gas-filled type containing an organic compound, substantially free from oxidizing material, applied in the form of a solution to the filament thereof.

3. An incandescent electric lamp of the gas-filled type to which has been applied a solution of a carbon compound substantially fiee from oxygen.

4. An incandescent electric lamp of the gas-filled type comprising a filament coated with a derivative 0 diphenyl.

5. An incandescent electric lamp of the gas-filled type containing a filament which as-applied thereto, a solution of an amino compound. 7 r

6. An incandescent electric lamp of the gas-filled type comprising a filament coated with a cyclic carbon compound free from oxygen.

11. An incandescent electric lamp of the gas-filled type comprising a tungsten filament to which has been applied about a 2% solution or henzidine.

12. A getter for g s-iilled incandescentv electric lamps comprising a cyclic organic compound substantially free from oxygen.

13. A getter suitable for gas-filled incandescent electric lamps comprising a derivative of diphenyl.

14. A getter suitable for incandescent electric lamps of the gasfilled type comprising an amino compound.

15. A getter suitable for gas-filled incandescent electric lamps comprising benzidine.

16. A getter suitable for incandescent electric lamps of the gas-filled type comprising a solution of benzidine.

In testimony whereof I have hereunto subscribed my name this 15th day of May, 1923.

DANEL SNYDER GUSTIN.