US1109886A

US1109886A - Manufacture of electric filament.

Info

Publication number: US1109886A
Application number: US68820398A
Authority: US
Inventors: Carl Auer Von Welsbach
Original assignee: WELSBACH LIGHT CO
Current assignee: WELSBACH LIGHT CO
Priority date: 1898-08-09
Filing date: 1898-08-09
Publication date: 1914-09-08
Anticipated expiration: 1931-09-08

Description

CARL AUER VON WELSBACH, OF VIENNA, AUSTRIA-HUNGARY, ASSIGNOR TOWELS- BACH LIGHT COMPANY, OF GLOUCESTER NEW JERSEY.

CITY, NEW JERSEY, A CORPORATION OF MANUFACTURE OF ELECTRIC FILAMENT.

No Drawing.

To all whom it may concern:

Be it known that I, Dr. CARL AUER VON WELSBACH, va subject ofthe Emperor of Austria-Hungary, residing at Vienna,' Austria-Hungary, have invented or discovered a new and useful Improvement in the Manufacture of Electric Filaments, of which the following is a specification.

The object of my invention is to produce a filament substantially of osmium; another object is to provide a method of obtaining such a filament, and to this end to cover a platinumor other suitable wire with a coherent compact layer of 'osmium or an alloy thereof of, suflicient thickness of a homogenous character of requisite flexibility.

In the practice of. my invention I produce upon a platinum or suitable wire a number of superposed layers of osmium or a compound thereof. Subsequently the platinum or other wire is caused to form an alloy with the coating containing osmium. Afterward the platinum or other material of the wire is volatilized in whole or in part leaving a filament containing osmium or osmium alloyed with the metal of the wire. Such a filament is somewhat pliable, is homogeneous and well adapted for use in electric incandescent-lamps.

I have obtained good results in practice by the use of a platinum wire and I will describe my invention in connection therewith.

I prepare a diluted osmium compound in the form of a solution rendered, if necessary, a little more consistent by the addition of finely divided osmium; or another solid osmium compound like sulfid or tetra-hydroxid may be used.- I coat the platinum wire with such solution either by means of a brush orother appropriate implement, or

by passing the wire through the liquid.-

The wire is repeatedly passed through the liquid and heated to the drying point between each immersion or application until a coating of the desired thickness-is obtained. It may be remarked that it is best that each layer should be thin, so that the described operation of supplying each separate coat and then heating it must berepeated many times in order to make the filament sufficiently thick. Although it may be accomplished with one sufliciently uniform coating application and of a drying heat. By thus depositing the osmium coating slowly and uniformly the osmium filament finally Specification of Letters Patent.

Patented Sept. 8, 1914.

Application filed August 9, 1898. Serial No. 688,203.

color. A brittle alloy of osmium and plat-inum may result from the above described operation, but such an alloy lacks perfect homogeneity. However, by gradually increasing the heat to which the filament is subjected by the passage through it of an electric current to the required temperature,

the platinum of the alloy mayjbc almost completely volatilized without fusing the alloy itself while at the same time the described characteristics of the finished filament are insured. It is of importance that a su-fiiciently thick and uniform coating be obtained before the wire is subjected to the final gradual application of the electric current up to the production of a temperature at which the core wire will volatilize. In lieu of platinum other metals may be used provided they are sutliciently ductile and resist temperatures to which the filament is exposed in the course of its preparation, as well as other conditions to which the filament is subjected in the course of its manufacture.

As an example of the reducing gas to which reference has been made I may refer to gas obtained from the center of a Bunsen tube which is ignited at its air inlets which contains hydrogen, carbon-monoxid and hydro-carbons, and which gas also con: talns water vapor.

One purpose of the application of hea between each. application of the described coating is to reduce the coating to the metalhc state, that is, in the resent instance to osmium. Instead of supplying osmium or.

k osmium compound in the form of a solution,

as has been referred-to, a very thin platinum which will form a kind of emulsion of the components. Ruthenium and rhodium either in whole or part or with osmium or its compoundsmay be used.

It will be understood that, in the method claims herein, I intend to include by the expressions coatings containing osmium and coating containing osmium, a coating or coatings wherein osmium appears in any of the specific forms described, e., either in the form of a compound, or in the metallic form, or as a' mixture thereof.

Having thus described my invention, what I claim is: Y

. 1. The herein-described process of making filaments for electric incandescent lamps, which consists in repeatedly applying successive coatings containing osmium to a wire and subjecting the same to the action of a drying heat between each coating, and then subjecting the coated wire to the action of an electric current in a. protective atmosphere oxidizing as to any carbon present in the coating, until it is raised to a temperature higher than the volatilizing temperature of its core; substantially as set forth.

2. The herein-described process of making filaments for electric lamps, which consists in repeatedly applying coatings containing osmium to a wire and subjecting the same to the action of heat between each coating, and finally exposing the coated Wire in a protective atmosphere oxidizing as'to any carbon present in the coating, to a gradually increasing temperature which finally is greater than the volatilizing temperature of the core; substantially as set forth.

3. The herein-described process of making filaments for electric lamps, which consists in applying coatings containing osmium to a platinum wire and finally subjecting the coated wire to the action of an electric current in a protective atmosphere oxidizing as to any carbon present in the coating, up

to a temperature beyond the volatilizing temperature of the platinum; substantially as set forth.

a. The herein-described process of making filaments for incandescent lamps, which consists in applying a coating containing osmium to a wire, then subjecting the same to a drying heat and then to a gradually increasing electric current in a protective atmosphere oxidizing as to any carbon present in the coating, until the temperature of the wire core exceeds its temperature of volatilization; substantially as set forth.

5. The herein described process of making metallic filaments for incandescent lamps, consisting in coating a wire core with a coating containing a metal having a point of fusion above the volatilizing point of the wire core, then subjecting the same to a drying heat and then to the action of the electric current, in the presence of a reducing gas, until sufiicient heat has been developed to volatilize the wire core and leave the metallic particles in a cemented or coherent condition; substantially as set forth. 6. The herein described process of making metallic filaments for incandescent lamps, consisting in coating a wire core with a coating containing a metal having a point of fusion above the volatilizing point of the wire core, subjecting the same to a drying heatandthen to the action of the electric current, in the presence of the gas obtained from a Bunsen tube ignited at its air inlets, until sufficient heat has been developed to volatilize the wire core and leave the metallic particles in a cemented or coherent condition; substantially as described. Signed this 27th day of July 1898.

DR. CARL AUER vomvttselcu.

,VVitnesses LUDWIG HAILIN GER, Anonr GALLIA.