US1062305A - Incandescent lamp. - Google Patents

Description

Witnesses G. P. STEINMETZ.

INGANDESCBNT LAMP.

APPLICATION FILED SEPT. 13, 1908.

Patentd May 20, 1913.

I UNITED STATES PATENT-OFFICE. v

CHARLES r. s rnmmn'rz, or SGHENECTADY, NEW YORK, AssIGNon TO GEKEBAL ELECTRIC COMPANY, A coaronarxon or NEW YORK.

mcnnnnscnn'r LAMP.

Specification of Letters Patent.

Applicationfiled September 8, 1903. Serial No. 452,057.-

ma ed s 20, -1913-.

. phenomena are in the nature of electrical bulb.

discharges taking place across the leadingin wires or parts of lamp filaments across which adifierence of potential exists. The discharge in some cases is invisible and may harm the filament only very slowly, or it may be visible, continuing visible for a short time and then ceasing. In the latter case, of course, the filament is damagedmore rapidly. The discharge seems more likely to take place when the vacuum in the lamp has deteriorated, because of the liberar tion of gases occluded by the filament or condensed upon the inside walls of the lamp According to my invention I dispose .a wire strip or globule of met-allicmagnesium, calcium or lithium, or, alloys containing these metals, near the leading-in wires of thelamp in a manner hereinafter described,

, so that the electrical discharge takes place across these wires or strips in preference to taking place between adjacent. parts of the filament, or filaments. The discharge seems to have the efiect of vaporizing a small amount of these metals. I find that this apparentlyhas the effect of completely absorbing or abstracting the gases which may have accumulated in the globe, and in this way the high vacuum is automatically restored and maintained. My invention is illustrated in the accompanying drawings,a'nd will be more clearly understood by reference to the following description taken in connection therewith Figure 1- shows an incandescent lamp in which the filament is arranged in several loops, and illustrates one way of attaching the magnesium or calcium w res; Figs. 2, 3

; illustrate diagrammatically alternative ways of attaching the vaporizable metals; Fig. 4 is an enlarged view showing how the mag- I prepared to state.

enough to carry away nesium wires may be attached without welds mg.

In Fig. 1 a lamp is shown of the type now commonly used 1n connection with metallic filaments. The filament loops 1, are supported by wires 2 attached to the standard 3,

and are arranged in the usual manner within'the glass bulb 4. Current is'supplied to the filaments l by.intermediate leading-in w1res.5, which may be copper, nickel or platinum, but which in either case are at' tached to a short piece of platinum wire 6,

passing through the glass stem 7. Wires 8 consisting of oneof the metals mentioned,

say magnesium, are attached to the leadingin wires 5, as by welding or attaching them as is lllustrated in Fig. 4: to whichre erence will again be made.' The magnesium wires 8 are so arranged as to approach oneam other more closely than do the leading-in wires or the adjacent legs of the filament to which the leading-in wires are attached, so that the discharge will take place across the space between the magnesium wires 6 and not at other points. As above explained, a

small amount of metallic magnesium will be vaporized by the discharge, and this a parently has the effect of absorbing t e liberated gases and producing a practically perfect vacuum. As to the exact cause to which this effect is due, I

am not at present In Fig. 2 thevmagnesium or calcium wires are represented as applied-to a single loop of filament; but, of course, they may be applied in the same way with a multi-loop lamp. In this figure the leading-in wires 6,

magnesium wires 9 and the'filament 1 are all in series,'th e magnesium wires, 9 serving to carry current from the platinum leadingin wires 6 to the filament 1. The magnesiu'mwires are here shown as being welded to the filament 1 at one end and to the leading-in wires 6- at the other end. The wires 9 are bent toward each other as is clearly.

shown so that the electricaldischarge will be sure to take place between the magnesium wires instead of between the opposite legs of the filament or between the leading-in wires. The wires v9 must be made heavy the heat conducted thereto by the incandescent filament with sufficient rapidity to prevent their melting.

Fig. 3 is a view showing the filament 1 attached to intermediate leading-in wires which are bent toward each other and are connected in turn to the platinum leading-in wires 6 in the usual manner. A small lobule of lithium 1-0 is attached to the lea ingin wires 5 at points where the distance between these wires is least. -The lithium will adhere readily to these wires because of its small bulk' and when the electrical discharge takes place it will vaporize a small amount of the lithium which, as has been stated, will absorb gases.

Fig. 4 is an enlarged fragmental view of the stem of the lamp. The intermediate leading-in wires 5 are shown, each connected at one end by a weld to the platinum wire 6 assing through the glass stem 7 in Fig. 1. --h,e filament loops 1 are not shown in this figure but of course are to be understood as attached .to the other ends of the wires 5. Magnesium ribbons 11 are attached to the wires 5 by piercing a hole through the ribbons at either end, slipping the wires 5 through these holes, and then. pinching the ends of the ribbons 11 around the leading-in wires 5 as is clearly shown in the figure, the magnesium ribbons being bowed toward each other, so that if an electrical discharge takes place it will be sure to take place bevelop, a filament disposed therein, and a conductor containing metal whose vapors havegreat afiinity for gases connected with Wires supplying current to said filaments and conductors consisting of metals having great afiinity for gases when vaporized elec-, trically connected 1 to said leading-in wires the distance at some point between said condoctors being lessv than that between the leading-in wires, said conductors forming at said point terminals for. the easiest path for electrical discharges across the filament circuit and being adapted to vaporize by such discharges upon a deterioration of the vacuum in-the envelop during operation of the lamp.

4. The combination in an incandescent lamp of an evacuated envelop, filaments disposed therein, means for supplying said filaments with current, and means made operative by a deterioration of the vacuum in said envelop during the life of the lamp for producing therein a metal vapor having a great aflinity forxgases and thereby automatically acting to restore the vacuum. during operation of the lamp.

5. The combination in an incandescent lamp of an evacuated envelop, filaments disposed therein, means for supplying said-filaments with current, and means made operative by the electrical discharge occurring upon a deterioration of the-vacuum in said envelop for producing therein a metal vapor having a great aflinity for gases and thereby automatically acting to restore the vacuum during operation of the lamp.

In witness whereof, I have hereunto set my hand this 5th day of September, 1908.

CHARLES P, STEINMETZ.

Witnesses:

BENJAMIN B. HULL, MARGARET-A. DELEHANTE.

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