US1132307A

US1132307A - Arc-lamp.

Info

Publication number: US1132307A
Application number: US69790312A
Authority: US
Inventors: John T H Dempster
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1912-05-17
Filing date: 1912-05-17
Publication date: 1915-03-16
Anticipated expiration: 1932-03-16

Description

J. T. H. DEMPSTER.

ARC LAMP.

APPLICATION FILED MAY 17,1912.

1,132,307, Patented Mar. 16, 1915.

Witnesses: Inventor:

John T. H.Dempster,

Hus fittorney.

UNITED STATES PATENT OFFICE. I

JOHN '1. H. DEMPSTER, OF SCQHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

ARC-LAMP.

Specification of Letters Patent.

Patented Mar. 16, 1915.

To all whom it may concern Be it known that I, JoHN T. H. DEMP- STER, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented new and useful Improvements in Arc-Lamps, of

which the following is a specification.

My invention has reference to an arc lampof the flaming-type.

It has heretofore been proposed to make electrodes which will support a flaming are by mixing a salt or salts, the vapors from which are adapted to impart luminosity to the arc, with carbon, and make electrodes from such mixture. With electrodes of this trodes at such a point that the material is fused by the heat from the arc and is vaporized into the arc.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a vertical sectional view, partly in elevation, showing a lamp in which my invention is embodied, and Fig. 2 is a side elevation showing the arrangement of the electrodes.

I have shown my invention embodied in an arc lamp of the inclosed type, although it will be understood that it is not limited to this character of lamp.

. In the drawings, 1 is the bottom plate of the lamp' secured to and supported by suitable spacing bars 2. The lamp which I have shown comprises a rather large fiat condensing chamber 3 in which the fumes from the are are deposited. This chamber is formedby'an upper member 4; l and a lower member 5 suitably joinedatogether. The upper member 4 is provided at its inner edge with a vertical cylindrical extension 6, having at its upper edge an inwardly extending flange 7 which is secured to the bottom plate 1 of the lamp. The lower portion 5 of the condensing chamber extends somewhat downwardly and inwardly and its inner edge is turned down to form a vertical wall 8, within which is received and secured an annular ring 9. The inner globe 10 is seated against the ring 9 and is held in engagement with the same by a spring seat 11 of any usualconstruction, the bails for which are not shown in the drawing. The outer globe 12 is supported at the top by an. annular ring13 which may conveniently be hinged at 14 and secured in position by a suitable fastening means 15, the details of which are not here shown. The upper electrode 16 comprises two converging

members

16 and 16 which are received within

sleeves

17 and 18 within which the

members

16 and 16 are adapted to slide freely. A lower electrode 19 cooperates with the upper electrode and it will be understood that suitable mechanism is provided in the lamp for separating the lower .electrode from the upper to establish the arc, and if desired, for regulating the same. The rod or bar 20 is formed of some fusible material, the vapors from which are adapted to impart luminosity to the arc, and is so arranged that it is fed into abutting engagement with the. upper electrode at such a point that the heat from the arc will fuse the tip of the bar 20. The bar 20 is guided by a sleeve 21, and I have here shown the same fed into abutting engagement with the upper electrode by gravity. It will be understood, however, that additional means may be provided for positively feeding this bar if desired. A casing 22 for p the lamp surrounding the cylindrical extension 6 and supported by.-the upper por-- tion 4 of the depositing chamber, houses the operating mechanism of the lamp. The casing may conveniently be formed in two portions which are fastened together at 23.

In operation the electrodes are separated to establish the arc. As soon as the tip of the. upper electrode becomes sufiiciently heated from the arc, the tip of the bar 20 which is in engagement with the upper electrode begins to fuse, and thematerial therefrom runs down over the arcing face of the upper electrode where the material, of which the bar 20 is composed, is vaporized and carried into the arc imparting luminosity to the same. Such an arrangement possesses the advantage that the amount of light giving materialentering the arc-is automatically regulated. If, for instance, the tips of the electrodes become heated to an abnormal temperature, more .of the fusible material will be melted and running over the tip of the upper electrode will cool the same, thereby decreasingthe amount of material that will be fused. On the other hand, if the tip of the upper electrode is cooled to an abnormal temperature, less of the fusible material will be melted, thereby permitting the temperature of the tip of the positive electrode to increase.

It will be seen that my invention permits the use of electrodes for supporting the are which are made of good conducting material, such as carbon, Without burdening the electrode with light giving materials which. are usually poor conductors and which interfere, when incorporated in the electrode itself, with the proper burning of the arc. lVhen' made of carbon the electrode may be made more dense than would be possible if the same were .miXed with light giving materials, thereby increasing the life of the electrode. At the same time the labor involved in thoroughly. mixing the light giving material with the carbon is avoided.

While I have mentioned carbon as a material well adapted for the electrode material in my invention, it will be understood that in case a still more slowly consuming material is desired, then metallic substances may be employed for supporting the are. In such case the metallic, substances of the electrodes themselves give luminosity to the arc, which luminosity may be enhanced and the color of the light may be modified by theuse of my invention.

A bar or rod may be made, in accordance with my invention, by melting together equal parts of calcium fluorid', sodium fluorid and potassium fluorid, and casting the molten mixture into the form of a rod or bar, as desired. In case it is desired to further lower the melting point of the rod, the proportion of the alkaline materials may be increased. While I have mentioned fiuorids as well suited for the purpose of my invention, it will be understood that it is not limited to any specific light giving materials, as other materials such as titanatesand oxids, or mixtures with or without the material would be made to abut against the electrode at a point farther removed from the arc than would a rod of more refractory material. What I claim as new and desire to secure by Letters Patent of the United States, is 1. In an arc lamp, a-pair of cooperating electrodes between which an arc may be formed, in combination with a fusible rod containing or composed of light giving materials, abutting against one of the electrodes in such vicinity of the are as to feed the fusing rod-material into the arc.

2. In an arc lamp, the combination of an upper and lower electrode between which an arc may be formed, and means for imparting luminosity to the arc, consisting of a fusible rod containing or composed of light giving materials and adapted to be held in abutting engagement with the upper electrode above the arc.

3. In an arc lamp, a pair of electrodes betweenv which an arc may be formed and supported, one of said electrodes having arcing face maintained substantially stationary with reference to the lamp, in combination with a rod of fusible light giving material held in abutting engagement with said electrode in such vicinity of the arc asto feed the rod-material into the are.

4. In an arc lamp, an upper and a lower electrode, between which an arc may be formed and supported, the upper electrode comprising a pair of abutting members, and

a bar of fusible light giving material held in abutting engagement with said abutting members in the vicinity of the arc.

In witness whereof, I have hereunto, set

my hand this 16th day of May, 1912.

JOHN T. H. DEMPSTER.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.