US2042140A - Electric gaseous discharge device - Google Patents

Description

May 26, 1936. U 2,042,140

ELECTRIC- GASEOUS DISCHARGE DEVICE Filed Aug. 17, 1954 &' .1

INVENTOR 7v 6.27 I ATTZRNEY Patented May 26, 1936 Albert Biinger, Berlin-Pankow,

Germany, as-

signor to General Electric Company, a corporation of New York Application August 17, 1934, Serial No. 740,304 In Germany September 7, 1933 4 Claims.

The present invention relates to electric gaseous discharge devices generally, and more particularly to discharge devices of the type which are operated with a relatively constricted arc.

5 The particular object of the invention is to provide a novel method and means for controlling the arc path within a discharge device in order to prevent the are from impinging on the envelope wall. A further object of my invention is to utilize the usual arc stabilizing impedance to produce this new result. Still other objects and advantages of my invention will appear from the following detailed specification, or from an inspection of the accompanying drawing.

The invention consists in the novel steps of the method and in the unique combination of ele- .ments which is hereafter set forth and claimed.

In operating gaseous electric discharge devices, such as a high pressure mercury vapor lamp with a constricted arc discharge, difficulties are encountered whenever an attempt is made to operate the device with the are extending in. other than a vertical line. These difliculties are caused by the fact that the arc tends to rise, due to the heating of the gas in the arc stream, and thus curves toward and impinges upon the upper wall of theme tube as the latter is moved toward a horizontal position. The glass which is commonly used for these are tubes is not adapted to withstand the ensuing severe localized heating and hence softens, allowing the tube to lose its shape and at the same time evolving copious amounts of gas into the discharge path, either of these effects alone being enough to ruin the discharge 85 device.

I have now discovered that this difllculty is entirely overcome by a magnetic force of a magnitude which just neutralizes the upward force which is exerted upon the arc stream. as a result of the unequal temperatures within the lamp, the arc thereupon continuing to pass down the center of the arc tube regardless of the position of the latter. As a result a serious limitation on the utilization of these discharge devices, particularly as light sources, is now eliminated without any change in the arc tube itself. Since it is essential, for best results, that this magnetic force should be proportional to the current and in phase therewith I have found it to be desirable to use 'one or more inductances connected in series with the arc to produce this magnetic field. These inductances serve to stabilize the arc and thus replace, in whole or in part, the stabilizing im- 55 pedance which is ordinarily used with this type ducing lines of force whose direction is indicated of device when it is operated on a constant potential circuit.

For the purpose of illustrating my invention I have illustrated two embodiments thereof in the accompanying drawing, in which 5 Fig. 1 is a schematic diagram of an electric gaseous discharge lighting tube, together with a group of series inductances, and

Fig. 2 shows a schematic diagram of a modifiv cation of the structure of Fig. 1. 10

As shown in this drawing, with particular reference to Fig. 1, the discharge device has an elongated tubular envelope 1 of glass or the like which contains any suitable gas or vapor, or mixture thereof. For example, a filling of argon 15 at a pressure of the order of 5 mm. of mercury, together with enough mercury to produce a pressure of the order of an atmosphere when it is all vaporized, has been found to give exceptionally good results. A pair of electrodes 2 and 2 are 20 supported by the inleads, 3 and 3, respectively, which are sealed into opposite ends of said envelope. These electrodes, which are of any desired type, .are only conventionally illustrated, since the structure thereof forms no part of my invention. It may be remarked in passing, however, that these electrodes are preferably thermionic, with the necessary heating provided by the discharge itself, or in some cases, by auxiliary heating means. Various well known means 30 of facilitating the initiation of the discharge, such as auxiliary electrodes or conducting strips on the surface, may also be employed where de-- sired, but since they form no part of the present invention they will not be described in detail. The inlead 3' is connected directly to the terminal 4 of a suitable source of alternating current of customary frequency, while the inlead 3 is connected through a series of inductances 5, 6, I, 8 and 9 to the other terminal 4 of said source. The 40 inductances 6, 1, 8 and 9, which are preferably iron cored are arranged more or less uniformly over the midsection of the tube l, with their axes substantially horizontal and normal to the axis of said tube. The inductance 5 is omitted in some cases, where the other inductances are of suflicient size to stabilize the arc.

In the use and operation of this lamp the arc current flows through the inductances 5, I, 8 and 9, and thus produces a magnetic field about each thereof, the lines of force of which at a given moment are indicated by the dotted lines 6', I, 8 and 9'. At the same instant the arc current flowing between the electrodes 2 and 2 is proby dotted lines Ill, ll, l2 and I3. Since the inductances 6, I, 8 and 9 are so wound that the lines of force of both said inductances and the are current are in the same direction above the arc itself, there is a repulsive force exerted upon the arc stream. As a result of this force the arc is forced downwardly to the path indicated by the long-dashed line I4, instead of permitting it to take the path which is indicated by the dot and dash line l5 which it would normally follow in the absence of the inductances 6, I, 8 and 9. The regulation of this magnetic force in order to obtain this straight line discharge along the center of the tube is very simple, since the strength of this force depends both upon the distance between the inductances and the arc and upon the relative direction of the lines of force. Hence the arc can be brought into the desired position in the tube l either by adjusting the gap between the difierent inductances and'the tube, or by changing the angle which they form with the discharge path. Furthermore the number of turns on the different inductances may be made different, it being noted that'a relatively greater magnetic force is needed in the vicinity of the electrodes than is required in themiddle of the arc.

In case it is desired to arrange the inductances below the arc tube I it is necessary to reverse the direction thereof, as shown in Fig. 2, so that the lines of force 6', I, 8' and 9' are in the opposite direction to the lines of force I0, I I, I2 and I 3 below the arc path. With this arrangement the arc is pulled rather than forced downwardly and follows the path it as in Fig. 1.

While I have illustrated my invention by reference to certain embodiments thereof it is to be understood that various omissions, substitutions and changes may be made therein, within the scope of the appended claims, without departing from the spirit thereof, it being obvious, for example, that the exact number of inductances employed to influence the path of the are is immaterial, and may be as small as one. and that these inductances may also be in part above and in part below, if desired, instead of all in a single position, as shown.

What I claim as new and desire to secure by Letters Patent of the United States is:-

-1. An electric gaseous discharge device comprising a sealed envelope containing a gaseous atmosphere and having electrodes sealed therein, said envelope being mounted with the electrodes in such relation that a line between said elec-v trodes is at an angle to the vertical, wherebyv forces are produced during operation tending to move the arc stream away from said line, in combination with means to produce a magnetic field within said envelope in such a direction and of such an intensity that the magnetic reaction thereof with the normal arc current equals the forces tending to move the arc stream out of a straight path within said device.

2. An electric gaseous discharge device comprising a sealed envelope containing a gaseous atmosphere and having electrodes sealed therein, said envelope being mounted with the electrodes in such relation that a line between said electrodes is at an angle to the vertical, whereby forces are produced during operation tending to move the arc stream away from said line, in combination with means to produce a magnetic field within said envelope in such a direction and of such an intensity that the magnetic reaction thereof with the normal arc current equals the forces tending to move the arc stream out of a straight path within said device, said means comprising an inductance connected in series with said device.

3. An electric gaseous discharge device comprising a sealed envelope containing a gaseous atmosphere and having electrodes sealed therein, said envelope being mounted with the electrodes in such relation that a line between said electrodes is at an angle to the vertical, whereby forces are produced during operation tending to move the arc stream away from said line, in combination with a plurality of inductances connected in series with said device, the relative position of said inductances with respect to said device being adjusted so that the magnetic reaction between the field produced thereby and the normal are current equals the forces tending to move the arc stream out of a straight path within said envelope.

4. The method of maintaining a constricted arc discharge which is inclined to the vertical in a gaseous atmosphere out of contact with the wall of a vitreous envelope which comprises producing within said envelope a magnetic field whose intensity and direction is such that the magnetic reaction with the normal arc current equals the forces tending to move said are into contact with said wall which result from the inclination of said are ALBERT BfiNGER.

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