US1537680A - Incandescent-arc device - Google Patents

Description

May 192s.

G. KLA

INCANDESCENT ARC DEVICE Filed July 28 1924 lnv Patented May 12, 1925a STATES v anna PATENT o FIc-E.

GljN'IHER KLAHRE, 0F BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COM- PANY, A CORPORATION OF NEW YORK.

INCANDESCENT-ARG DEVICE.

Application filed July 28, 1924. Serial No. 728,530.

T 0 all whom it may concern:

Be it known that I, GiiNTHEn KLAHRE', a citizen of Germany, residing at Berlin, Germany, have invented certainnew and useful Improvements in Incandescent-Arc Devices, of which the following is a specification.

The present invention relates to devices in which an arc-like discharge is operated in an inert gas between refractory electrodes and is particularly concerned with the starting of the discharge between said electrodes by contact and separation of electrode members.

Indevices of this type which are provided with contact starting mechanism, a separation of the electrodes usually is effected by a thermostatic member, which. when heated, draws the electrodes apart. with the resulting formation of an are. To insure positive contact between the electrodes, when the arc is not operating and to prevent the anode from being drawn away from the cathode prematurely. the anode heretofore has been arranged to press against the cathode when the device was not operating. As a result of this condition the electrodes tended to remain in contact for several seconds, while current passed through them. Because of the high current density at the points of contact it often happened that the anode became welded or frozento the cathode before the thermostatic starting device could cxert sufiicient force to separate the electrodes. As a result the thermostatic device sometimes was unable to separate the electrodes and in that event thedeviee was rendered inoperative.

According to the present invention a construction is provided whereby a positive starting of an arc lamp, or other device, is attained without any danger of welding of the electrodes. This result is obtained by providing a resiliently supported stop or motion-limiting device. against which the movable electrodes will bear. and from which it will be separated. preferably with l a rubbing contact when the arc is started.

This stop device is conductively connected with the opposite electrode, preferably the cathode, so that when the movable electrode, in the preferred case the anode, is

. separated from the stop device, an arc will be started which will later be transferred to the 'electrode to which the stop device is connected.

when the arc is operating, and Figs. 3, 4, y

5 and 6 illustrate modifications of my in vention.

The lamp shown in Fig. 1 comprises a glass bulb a containing an inert gas, such as argon, neon, nitrogen and provided as usual with a screw'base j, to which the leads 0 and d are conductively connected. The electrodes and starting mechanism are carried by a glass stem 6 into which the leads 0 and d are sealed in the usual man nor. The bar-shaped cathode e, which preterably consists of tungsten, and which may be provided with a coating of thorium or other oxide, is supported uporrthe stem 3) by wires f and g. The anode it has been shown as of spherical shape, although of course it may assume other forms. The anode which preferably also consists of tungsten is carried by a support 2', which is mounted upon the stem b of the lamp 'through the intermediary of a thermostatic held by the radial supports w arranged around the stem of the lamp and is connected to the terminals of the lamp in series with the electrodes, the circuit being from the leading-in conductor (2 through the resistor wire n, a support 0, the anode stem 2', the stop plate m, the cathode support f to the opposite leading-in conductor 0. One portion of the resistor n is arranged as indicated by 0 approximately parallel to the bi-metal stripk, so that when the lamp is, switched on the thermostatic strip is is not only heated by current passing therethrough, but also by heat radiated from the resistor 0 and hence is caused to separate the anode h from the stop plate Z. This separation occurs by a curved motion about the support of the anode in the direction of the I strikes the end of the cathode as shown in During the brief period of simultaneous motion of the anode and the stop plate, the anode slides somewhat upwards on the surface of the stop plate and therefore the anode does not remain long enough in contact at one particular point. to permit welding. The distance between the stop plate and the cathode is so adjusted that the arc is formed by the separation of the anode andthe stop plate at the int-taut of contact ot the stop plate with the cathode. Hence, the arc immediately jumps over to the cathode. The anode may continue to move in the direction indicated by the arrow through the action of the thermostatic support until it remains in the position shown in Fig. 2. being separated from the cathode by a distance suitable for the operation of thc arc. The stop Z prclcrably consists of a polishci'l tungsten plate to facilitate the sliding of the are upon its surface in order to prevent displacement oi the anode and the stop plate especially during transportation of the lamp. loop-shaped guide) surrounding the anode support '11 is mounted upon the s :m b.

Various modifications in the construction of the stop plate Z can be used. As shown in Fig. 3 thelimit sto may consist of a semispherical body Z, which is threaded directly upon the bar-shaped cathode c. a sp ral spring g. surrounding the cathode. being provided to hold the stop against the anode A. A forward travel of the stop Z is limited by a check 1'. but it is possible to omit the check r in the case the s n'ing tension is correctly chosen. The different positions of the stop I and the anode ll during starting are indicated by dotted lines in Fig. 3.

Although the cathodihas'bccn shown for illustrative purpo e in Figs. 1 and 3 as consisting of a bar. it may assume various other shapes. in Figs. 4- and 5 a block-shaped cathode s has been illustrated. In this case also the resilicnt supported stop plate Z may assume a. resting position againstthc cathode 5 during the operation oi the arc. although of course the forward travel of the stop plate may be limited b check as already shown in Fig. 3. I

In Fig. 6 a. construction has been shown in which the resiliency (if the stop 1 is secured by making the snp 'iorlsf, g of the cathode yielding As shown in Fig. 6 fiat springs t are inserted in the. cathode supports. the stop plate being in this case an integral part of thr cathode structure. 'When the anode It is; drawn in the direction of the arrow by the action of the thermostatio support, the cathode structure first follows the motion of the anode. The anode slides over the stop plate Z and fi'iially is separated therefrom, the are springing over 2. An arc device comprising the combina- I tion of a cathode adapted to be operated at incandescence, a cooperating anode, a yielding conductive stop member connected to one of said electrodes .and engaging when said device is notoperating with the cooperating electrode, and means for, drawing said cooperating electrode away from said memher. to strike an arc whcn the device is to be started. r

3. An arc device comprising the combination of an incandescible cathode. a cooperating anode. a yielding conductive member connected to said cathode, and engaging when said device is not operating. with said anode, a thermostatic support for said anode. and means for generating heat when said device is to be started to cause said anode to leave said stop member.

4. An arc device comprising the combination of a tungsten cathode, a cooperating anode, a stop mcn'iber. consisting of a smooth plate of refractory metal and a springy support. applied in said devicev to cause said plate to bear against said anode when the device is not operating. tcmpcraturc-responsire means for separating said anode and stop member and a resistor arranged to thermally actuate said separating means.

An incandescent arc lamp comprising the combination of a tungsten cathode (5-). a coopcrating' anode (It), a bi-inetal support (7:) for said anode, a mechanical limit stop bearing against said anode which comprises a smooth plate (Z) and a'resilient holder (m), a support (f) positioned to hold said stop against said cathode when the lamp is operating. means for heating said iii-metal support to cause the anode to leave said stop and to strike an arc. an enclosingenvelope (1:) and an inert gas hllinp therein.

0. An ciectric lamp comprising a scaled bulb. a gaseous iillinp therefor. cooperating electrodes of refractory metal. a yielding conductive stop member connected to the cathode. spaced away therefrom and located to engage with the anode when the device is not operating and means for separating said anode from the stop member with a rubbing motion when the lamp is to be lighted.

In witness whereof, I, have hereunto set my hand this 7th day of July, 1924.

' GUNTHER KLAHRE.

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