US1760524A

US1760524A - Electric discharge device

Info

Publication number: US1760524A
Application number: US59986A
Authority: US
Inventors: Rentschler Harvey Clayton
Original assignee: Westinghouse Lamp Co
Current assignee: Westinghouse Lamp Co
Priority date: 1925-10-02
Filing date: 1925-10-02
Publication date: 1930-05-27
Anticipated expiration: 1947-05-27

Description

May 27, 1930. H. c. RENTSCHLER ELECTRIC DISCHARGE DEVICE Filed Oct. 2, 1925 FIGQI FIG INVENTOR 'HARVEY C. RENTSCHL R BY ATTORNEY Patented May 27, 1930 UNITED STATES PATENT OFFICE CLAYTON RENTSCHLER, OF EAST ORANGE, NEW JERSEY, ASSIGNOB TO WEBT- INGHOU'SE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA ELECTRIC DISCHARGE DEVICE Application filed October 2, 1925. Serial No. 59,986.

This invention relates to electric discharge devices and more particularly to glow discharge devices in which the discharge takes place in a rarefied gaseous atmosphere. The invention is especially concerned with the production of a discharge device utilizing a monatomic gas in which the starting voltage and the operating discharge voltage fall Within rather narrow and predetermined values and in which these voltages remain fixed within these narrow limits over a long period of time.

Such devices may be used for controlling or regulating the plate voltage in radio C11- 15 cuits when the plate voltage is obtained from rectified alternating current, throughthe use of the so-called B-battery eliminators. Another use for this type of a device is in a glow. discharge point-to-plate rectifier uslng an inert gas. Still another application of the device is in connection with protective devices, such as overload circuit breakers or the like. For all these purposes it is essential that the discharge start at a potential falling within relatively narrow limits and that the operating voltage is fairly definitely fixed within definite limits.

One of the objects of the invention is to provide a discharge device which will have a low starting potential and operating potential and which will be simple and rugged in construction.

Another object of the invention is to provide a gaseous discharge device of this nature I 3.6 which will be uniform and dependable in operation.

Another object is to provide a discharge device in which both the break down or starting volt-age and the operation voltage fall within 4 definite and relatively narrow limits.

Other objects and advantages will hereinafter appear.

I have found that when the anode of a point-to-plate discharge device, utilizing an 4 atmosphere of a monatomic gas, such as used for argon, or a mixture of monatomic gases, consists of mischmetal or a metal of the cerium group of rare earths, that the seasoning of the discharge device can be accomplished very simply and that a low starti g and operating potential may be obtained. Both of these potentials, moreover, will fall within definite limits and the device will operate continuously and uniformly within these limits over a long period of time. The misch metal appears to serve a double purpose. Residual impurities in the gas which come from the elements of the tube, such as insuflicie'ntly treated electrodes or which exist in the gas as impurities, will be cleaned up by the misch metal during the seasoning process. Also, during the operation of the tube, the impurities which may be liberated from the parts of the tube will be cleaned up and thus the operating characteristics of the device maintained uniform during the life thereof. At the same time some t of the misch metal will be volatilized -and condensed on the plate, thus giving a lower starting and o erating potential than would be obtained if the metal of the plate were composed solely of one of the common metals purposes of this kind, such as nickel, iron, etc.

In order that this invention may be more fully understood, reference will be had to the accompanying drawing in which,

Fig. 1 illustrates a discharge device partly in dsection embodying the present invention; an v Fig. 2 illustrates, diagrammatically, the method of utilizing the device for regulating the voltage.

The device comprises an envelope 1 containing a cathode 2, an anode 3 and a filling of a monatomic gas or mixture of such gases.

The anode 3 consists of a Wire 4 of nickel or other suitable material sealed' through the press 5 of the device and has'a strip of misch metal 6 clamped or otherwise suitably secured to the outer end thereof, although if desired,

the electrode may be composed entirely of misch metal.

The cathode 2 consists of a cylindrical plate concentric with the anode and supported from the press 5 by support wires 7 and 8. The cathode may be composed of nickel, 1ron, molybdenum or any other suitable metal.

The anode and cathode are provided with current conducting leads 9 and 10 joined to the wire 4 and the cathode support 7, respectively, and to the terminals 11 and 12 of the base 13.

To assist in starting the discharge, a pro ection in the form of a wire 14. extends from the cathode 2 into close proximity to the anode 3.

The envelope is preferably filled wltlrargon at a pressure of from about 3 to 7 m1lh meters of mercury, although other monatomic gases or mixtures of gases may be employed depending on the starting and operating potentials desired. After filling with gas and sealing off, it is necessary to subject the device to a treating schedule to develop the starting and operating characteristic thereof. Preferably, such treatment consists in operating the device on 220 volt alternating current with a protective resistance in series therewith for a short time and then seasoning the device at 110 volts alternating current for several hours. I

This treatment ionizes the gas and heats the anode to a sufficiently high temperature to render the misch metal active so that it is effective to thoroughly purify the gaseous filling. It also appears to render the cathode more sensitive or active and thus effective to initiate a discharge therethrough at a relatively low potential. It appears that a small proportion of the misch metal or some constituent thereof is sputtered, vaporized or otherwise deposited on the cathode from the anode. However, I do not desire to be limited by any particular theory.

Devices so produced have a starting potential of from about 100 to 125 volts and a minimum operating potential of about 80 to 100 volts depending somewhat upon the gas content. its pressure, the current drawn by the device, etc.

It is obvious that other treatments may be devised for developing the starting and operating characteristics of the device and that the invention is not limited to the particular treatment specified.

The misch metal serves throughout the life of the tube to maintain the gas in a pure condition. and the operating and starting characteristics uniform.

In some instances it may be desirable to use misch metal on the cathode as a getter in addition to its use on the anode. This would be particularly helpful if the gas used were not previously purified to a fairly high degree. If used on the cathode, the misch metal could be vaporized by high frequency induction or in any other suitable manner to clean up any impurities or common gases re- .purpose such as the operation of the radio tubes or other device 19. The voltage regulator 20 is placed across the line to maintain the voltage constant irrespective of fluctuations in the voltage of the alternating current source or of the number of devices in operation. A resistance 21 is provided for limiting the current to the desired maximum value. A suitable resistance 22 may be provided to enable current of different voltages to be utilized.

Preferably, the resistance 21 is so regulated as to permit a current flow of approximately 50 milliamperes through the regulator at about 90 volts when the switch 23 is closed and the load 19 disconnected. This current is sufficient to supply the plate current of radio receiving apparatus having a relatively large number of amplifying tubes. When the tubes or other device 19 are brought into operation, so as to draw current from the rectifier, the regulator, maintains the voltage uniformly at the desired voltage. i. e., about 90 volts. Should the voltage fall below the minimum operating potential of the regulator, it ceases to operate and the full rectified current is available for the devices 19. Immediately. however, the voltage increases to the starting potential of the regulator, it again comes into operation. It is essential. therefore, in order to insure a restarting of the regulator, that its starting potential be relatively low and close to its operating potentlal. The starting and operating potentials of the described embodiment of this invention renders it particularly efiicacious for this purpose.

It is obvious that the invention is susceptible of many embodiments and that various .a small anode therein and a relatively large cathode, said anode being formed in part at least of misch metal whereby a low voltage discharge through said device may be obtained.

3. An electrical discharge device comprising an envelope containing a monatomic gas, electrodes therein operable in the absence of thermionic activity and'a quantity of misch metal within said envelope for purifying said gas and reducing the starting and operating potentials thereof.

4. An electrical discharge device of the point-to-plate type comprising an envelope containing a rare gas, a small anode and a relatively large cathode therein and a metal of the cerium group of rare earth metals disto heat said anode to activate the cerium HARVEY CLAYTON RENTSClll-ER.

posed on one of said electrodes adapted to purify said gas and reduce the starting and operating potentials of the device.

5. A glow discharge device comprising an envelope, a filling of monatomic gas therein at a relativelylow pressure, and a plurality of electrodes within said envelope'operable in the absence of thermionic activity, one of said electrodes being composed chiefly of misch metal, whereby said device has a low starting and operating potential.

6. An electrical discharge device of the point-to-plate type comprising an envelope containing a rare gas, an anode and a cathode,

said cathode having a metal of thevcerium group of rare earth metals disposed thereon.

7. An electrical discharge device comprising an envelope containing a filling of argon gas, an anode and cathode within said envelope, said anode being formed in part, at least, of misch metal and said cathode containing a quantity of misch metal on the surface thereof.

8. An alternating current rectifier having a low starting and operating potential comprising an envelope containing argon, a relatively large cathode and a small anode therein, one of said electrodes having the uantity of misch metal thereon adapted to re uce the starting and operating potentials of the device and maintain such potential uniform throughout the life of the device.

9. The method of reducing the starting and operating potential of a gaseous discharge device containing a plurality of electrodes which consists in introducing a mutity of misch metal therein on one o the electrodes, passing a discharge through the device at a potential of approximately 220 volts to activate the misch metal and subsequently reducing the voltage and continuing the discharge to season the-device.

10. The method of reducing the starting potential of a. point-to-plate rectifier of the gaseous discharge t pe comprising forming the anode of said evice of a metal of the cerium group of rare earth metals and subjecting said device to a discharge sufiicient