US1990169A - Gaseous electric discharge device - Google Patents

Description

Feb. 5,' 1935. R. DELAS GASEOUS ELECTRIC DISCHARGE DEVICE 2 Sheets-Sheet 1 Filed Oct. 18, 1932 a M e D .Y B E m m L T e H mn Feb. 5, 1935.

R. L. DELAS 1,990,169

GASEOUS ELECTRIC DISCHARGE DEVICE 2 Sheets-Sheet 2 Filed Oct. 18, 1932 INVENTOR er-1e Louis Delas,

BY Mala ATTORNEY Patented Feb. 5, 1935 UNITED STATES 1,999,169 GASEOUS ELECTRIC DISCHARGE DEVICE Rene Louis Delas, Courbevoie, France, assignor to General Electric Company, a corporation of New York Application october 1a, 1932, Serial No. 638,408 In France October 29, 1931 4 Claims.

, The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices having thermionic electrodes.

-It is known in the art that a higher voltage is required to establish the gaseous electric discharge in such devices than is necessary to maintain said discharge after it has been established. For this reason such devices have heretofore been connected to transformers adapted to supply the necessary starting voltage and have been connected in series with a resistance or reactance adapted to dissipate the excess voltage during the operation of the device.

Circuits have been proposed wherein the energy formerly dissipated in the resistances or reactances has been utilized in heating the thermionic electrodes. Such circuits have, among others, two disadvantageous features (1) when potential is first applied to such circuits the voltage immediately available for starting is lower than that of the supply circuit, and (2) for a short interval during the starting period the heater of the thermionic electrode is surcharged and said filament carries almost twice its normal load.

The object of the present invention is to provide a gaseous electric discharge device having thermionic electrodes and adapted to start and operate on the 110 or 220 volt current sources of commerce. Another object of the invention is to provide a simple starting and operating circuit for gaseous electric discharge devices having thermionic electrodes. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims.

In the drawings accompanying and forming part of this specification three embodiments of the invention are shown, in which Fig. 1 is a schematic view of one embodiment of the invention and a circuit therefor;

Fig. 2 is a similar view of another embodiment and a circuit therefor, and

Fig. 3 is a similar view of still another embodiment and a circuit therefor.

Like numbers denote like parts in all the figures.

Referring to Fig. 1 of the drawings the new and novel gaseous electric discharge device comprises a tubular container 1 having a gaseous atmosphere therein such as nitrogen, neon, or a mixture of argon and mercury. Four indirectly heated, uni-potential, thermionic electrodes 2, 3, 4 and 5, such as the well known Hull cathode consisting of a metal shell, such as nickel, coated with electron emissive material, such as barium "oxide, and having a tungsten heater filament therein, are sealed into said container 1, two at each end thereof. Said electrodes 2 and 3, 4 and 5, are electrically connected to each other by leads 14.and 15, respectively. Heater filaments 6, '7, 8 and 9 are provided for said electrodes 2, 3, 4 and 5 respectively. One end of each of said filaments 7 and 9 is connected to said electrodes 3 and 5 respectively. The opposite ends of said filaments? and 9 are connected to said filaments 6 and 8 of said electrodes 2 and 4 through resistances 16 and 17 respectively. Said filaments 6 and 8 are connected to each other through resistance l3 and switch 10 and to the terminals 11 and 12 of an alternating current source of commercial voltage, such as 110 or 220 volts.

' In starting the device switch 10 is closed and current flows from terminal 11, through the filament 6, the switch 10, the resistance 13, the filament 8 and hence back to the terminal 12. The current consumption of said resistance 13 is such that the electrodes 2 and 4 are heated to their electron emitting temperature by filaments 6 and 8. When said electrodes 2 and 4 have reached such temperature the gaseous electric discharge starts'between said electrodes 2 and 4 on the normal potential of the source, such as 110 or 220 volts.

The discharge current then flows, on one hand, through the resistance 16, the filament '7, the electrode 3 and thence to electrode 2 over lead 14 and on 'the other hand through resistance 17, the filament 9, the electrode 5 and thence to electrode 4 over lead 15. The discharge current thus heats the filaments 7 and 9 which bring the electrodes 3 and 5 to their electron emitting, discharge suppogting temperature. Where desired, the discharge is supported during the operation of the device by said electrodes 3 and 5 alone and the discharge is transferred from said electrodes 2 and 4 to said electrodes 3 and 5 by opening switch 10.

Thus said electrodes 3 and 5 support the discharge only during the operation of the device and when said electrodes 3 and -5 first start into operation their electron emission is supplemented by that of said electrodes 2 and 4 to insure a safe and certain transference of the discharge thereto. It is obvious that an electric discharge device as described above having two sets of electrodes to support the discharge, one during the starting period and the other during the operating period, has a longer life than a similar device having but one set of electrodes which support the discharge during both the starting and the operating periods. Further, the external resistance essential in prior devices to absorb the excess potential after the starting of the discharge is not necessary in electric discharge devices made in accordance with the present invention, resistances 16 and 17 and the filaments 7 and 9 are sufiicient for this purpose. Thus part of the energy wasted in the ballast means of prior devices is utilized for the heating electrodes in the device of the present invention while abnormal loads on the heating filaments are avoided and the full line potential is immediately available at the electrodes for purposes of starting. It is apparent that where the resistance of the filaments '1 and 9 is of a suificiently high value the resistances 16 and 1'! are cut out of circuit, where desired, during the operation 01' the electric discharge device.

The embodiment of my invention shown in Fig. 2 has a slightly difierent circuit than that shown in Fig. 1 and is designed to operate on a much lower potential, 15 volts, for example, and is connected in series with other analogous devices.

Assuming that the potential drop between'the" electrodes is 11 volts the closing of switch 10 sends the current through the filament 6, the resistance 2'7, the switch 10 and the filament 8. After the electrodes 2 and 4 have been heated to an electron emitting discharge supporting tem perature, an electric discharge is established between them on the line potential. The filaments '7 and 9 are connected in series with said electrodes 2 and 4 and each of said filaments '1 and 9 consume two volts, for example. When switch 10 is open circuited said electrodes 2 and 4 are cut out of circuit and the full line potential is applied across said electrodes 3 and 5 which starts an electric discharge between said last named electrodes. It is obvious that a multiplicity oi such devices are adapted to be connected to each I at an operating temperature.

other either in series or in parallel as desired.

The embodiment of the invention illustrated in Fig. 3 has still a different circuit than that shown in Figs. 1 and 2. Electrodes 2 and 4, which are the starting electrodes, are separated a distance equal to or slightly less than the distance at which a discharge will start between them on the line potential when said electrodes are The electrodes 3 and 5 are separated a greater distance than said electrodes 2 and 4 and are connected to said electrodes 2 and 4 through resistances 18 and 22 respectively. Switches 19 and 20 are provided to break the electrical connection between said electrodes 2 and 3, 4 and 5 respectively. When the device is started into operation switches 10, 18 and 20 are closed and current fiows through the heater filaments 6 and 8 of said electrodes 2 and 4 respectively. Assoon as said electrodes 2 and 4 have been heated to an electron emitting discharge supporting temperature by filaments 6 and 8 respectively, an arc discharge takes place between said electrodes 2 and 4 on the line voltage. The discharge current then flows through resistances 16, 17, 18 and 22 and filaments 7 and 9 which heat the electrodes 3 and 5 to an electron emitting discharge supporting temperature and said electrodes 3 and 5 then participate in supporting the discharge in the device. The are current between electrodes 2 and 4 is then greater than that between electrodes 3 and 5 and the potential drop' between said electrodes 3 and 5 is obviously larger than that between said electrodes 2 and 4. The resistances 18 and 22 are rent between said electrodes 2 and 4 decreases while that between said electrodes 3 and 5 intrated in Fig. 3 makes possible an increase in the useful length of tubular devices such as that illustrated in Fig. 1 or an increase'in the diameter oi. globular devices such as that illustrated in Fig. 2 without increasing the voltage required to start the discharge in such devices. f

The above described electric discharge devices may be changed in various respects without departureirom the broad spirit and scope of the invention, for example, electrodes having one or more electrically insulated heat radiators are used, where desired.

What I claim as new and desire to secure by Letters Patent 0! the United States is 1. An electric discharge device comprising a container, a plurality of electrodes sealed therein, a gaseous atmosphere therein and a heater means for each of said electrodes, said electrodes being electron emitting, some of said electrodes supporting the discharge during the starting period and some of said electrodes supporting the discharge during the operating period, said first named electrodes being separated a distance less than the striking distance of said discharge.

2. An electric discharge device comprising a container, a plurality of electrodes sealed therein, a gaseous atmosphere therein and a heater means for each of said electrodes, said electrodes being electron emitting when heated, some of said electrodes supporting the discharge during the starting period and some of said electrodes supporting the discharge during the operating period,sa id first named electrodes being separated a distance less than the striking distance of said discharge,

the other electrodes being separated a greater distance than said first named electrodes.

3. An electric discharge device comprising a container, a plurality of electrodes sealed therein, a gaseous atmosphere therein and a heater means for each of said electrodes, said container having a bulb shape-and said electrodes being centrally located therein and electron emitting when heated, some oi said electrodes supporting the discharge during the starting period and some of said electrodes supporting the discharge during the operating period, said first named electrodes being separated a distance less than the striking distance of said discharge, the other electrodes being separated a greater distance than said first

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