US699232A - Method of treating ballast-wires for electric lamps. - Google Patents

Description

U ITED STATES PATENT OFFICE.

HENRY NOEL POTTER, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO GEORGE WESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA.

METHOD OF TREATING BALLAST-WIRES FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 699,232, dated May 6, 1902. Application filed July 14,1900- Serial No. 23,651. (No specimens.)

To ctZZ whom it may concern: I

Be it known that I, HENRY NOEL POTTER, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Treating Ballast-Wires for Electric Lamps, of which the following is a specification.

My invention relates to electric lamps of the type in which the light-giving element or glower is a conductor of electricity only when hot, and particularly to the devices employed in connection with the glowers for compensating for their decrease in resistance as their temperature increases.

The object of my invention is to provide a method of treating ballast devices of the character above indicated which may be easily practiced and which will provide a ballast device the temperature of which will increase uniformly throughout its length under the action of an electric current passed through it.

In the use of ballast devices consisting of freely-stretched iron wire supported in a chamber filled with hydrogen gas, which is a form that I have heretofore generally employed, I find that even the most accuratelydrawn wire does not heat up evenly through-' out its length upon the passage of a given current, and even though the wire be of exactly uniform diameter and density throughout, so that its specific electrical resistance and also its resistance per unit of length are absolutely constant, yet the location of the wire in the ballast-chamber as regards its dis tance from the walls of the chamber and also from the supporting-wires and other bodies 7 as the correction afforded by the iron ballast is limited as regards the range of temperature and has a sharply-defined temperature at which its usual correction begins, it is desirable that'the entire length of wire, or as much of the length as possible, should attain the critical temperature under the action of a given current.

I have discovered and demonstrated by experiment that iron ballast wires may be treated by heating them in the presence of a suitable compound containing iron, so that the iron will be deposited on the wire in such manner as to insure the desired uniformity of temperature and corrective effect throughout its length. The treatment that I have found eflicacious in practice involves the use of an organic compound of ironsuch, for example, as that formed by passing carbon monoxid (CO) over finely-divided iron which is heated to a temperature of from 40 to centigrade-the gaseous compound thus formed being iron tetracarbonyl Fe(OO) This gaseous compound when heated to a temperature of from 200 to 300 centigrade is decomposed and deposits its iron upon the heated surface. In order to treat the ballast-wire, which is mounted in an inclosin'g chamber, the air is exhausted from the chamber, and the latter is then filled with the above-mentioned gas. Current is caused to traverse the iron wire for such length of time as to raise its tempera ture sufliciently high to decompose the gas and produce a deposit of iron therefrom upon.

the wire. If different temperatures are produced in different parts of the wire, the hotter portions, which have the greater resistance, will receive the greater amount of deposit, and consequently the adjustment afiorded by the deposit will be such as to insure an even resistance and temperature throughout the length of the wire.

I desire it to be understood that other compounds of iron which will give up their iron when heated may be employed in lieu of the compound above specified without departing from my invention.

For example,pentacarbonyl,Fe(00),,whicl1 is a liquid that boils at 103 centigrade, or heptacarbonyl, Fe,(OO) which is a solid of comparatively low melting-point, may be employed, if desired, providing the conditions attending the practice of the method in any given case make it feasible to utilize such material. The use of one or the other of the last-mentioned compounds may be found more advantageous than the use of tetracarbonyl for the reason that they may be more easily stored and handled than a gaseous compound.

I claim as my invention 1. The method of treating ballast-conductors for electric lamps which consists in heating said conductors in the presence of a compound containing as one of its constituents, the material of which the ballast-conductors are composed to such temperature as to efiect a deposit of the material upon the conductors.

2. The method of treating iron ballast-conductors for electric lamps which consists in heating the conductors in the presence of a compound containing iron to such temperature and for such a period of time as will efiect decomposition of the compound and a deposit of the iron therefrom upon the conductors.

3. The method of treating iron ballast-wires consisting of heating them in an inclosing chamber containing a compound of iron to such degree and for such a period of time as to elfect decomposition of such compound and a deposit of iron on the ballast-wires.

4. The method of treating ballast-wires for electric lamps which consists in inclosing a wire in a chamber containing an organic compound of iron and heating the wire to such temperature and for such a period of time as will effect decomposition of the compound 25 and deposit the iron upon the wire.

5. The method of treating an iron ballastwire for electric lamps which consists in inclosing such wire in a chamber containing an organic compound of iron and passing an 0 electric current through said wire of such volume and at such pressure as will efiect a deposit of iron thereon in accordance with the resistance of the different portions thereof.

In testimony whereof Ihave hereunto sub- 35