US2165832A - Electron discharge device - Google Patents

Description

July 11, 1939 s. N. BARucH ELECTRON DISCHARGE DEVICE Filed Nov. 2s, 19:56

Patented July 11, 1939 Unirse. stares PATENT OFFICE 2,165,332 ELEo'raoN inscannen nevica Sydney N. Baruch, New York, N. it.

Application November 2d, i936, Serial No. 113,212

20 iaims. (m, Z50-$7.5)

This invention relates to the construction and operation of electron discharge devices, and particularly to devices which are suitable for use as relays, switches and illumination, which may be 5 started instantly upon application of a pre-deter mined voltage to the grid and may be stopped suddenly the instant a certain critical negative potential is applied to the grid, also to vary the density and conductivity of the arc stream and to vary the intensity of the discharge stream.

The o-bject of my invention is to produce electronic relays and electron discharge devices, in which the cathodes are not totally enclosed inechanically by the grids within the meaning of my v United States Patent application Serial No.

567,735, for Power translating apparatus, in which I completely enclose the cathode with a metallic screen grid structure, and that enclosure has no openings greater than the finely-spaced opening of the grid mesh itself, in that Way obtaining a positive ion sheath, which completely closes od lthe discharge path and extinguishes the arc, but in which the cathodes are effectively completely enclosed electrically by the grids, as in that application. Therefore, the function in this application is the same as in United States application Serial No. 567,735, and Patent applica- 'tion Serial No. 591,911.

I have discovered the following phenomenon: Every element when gasied has a natural inherent period of vibration; therefore, if there is more than one element each period of vibration is present in each `element and results in a mixed vibration due to the natural periods of the elements themselves and the eifect of the electric charge thereon. In an electron-gas discharge device, with an opening therein, the opening offers more or less resistance according to its size. However, this opening, when made sumciently large, will not prevent the ow of ionized gas between the cathode and anode after the device is operated for a very short time and a negative electric charge is placed on the grid, this by reason of the ion sheath effect which extends out across the openings to a degree depending upon the potential of the negative charge and the size of the opening. However, by elongating this opening by means of an electrically conductive tube or channel, the resistance, increases to such a der 5o' gree as to extinguish the tube.

In general, an electric eld extends between any two bodies charged to different electric polarities and, according to well established theory, is practically expressed by a strained condition of the 55 ether filling the space between the bodies. The

direction of these ether strains at each point in the space between the bodies iollovtr predetermined lines known as electric lines of field. These lines start from the positively charged body at right angle to the surface of the body and ter- 5 minate at the negatively charged body. The course of the lines between the bodies is determined by the conilguration of and the distance between the bodies, provided the space between the bodies is free and that there are no other obl0 jects therein. Therefore, the elongated channel which is the opening in the grid andis negatively charged, establishes the lines of force which both attract positively charged lons to the interior of the channel wall and, as the channel gets longer, l5 the positive ions pile up around the walls getting thickertowards the exit rof the channel and ccmpletely closing it, if it is long enough. The length of this channel will vary, due to the fact that the natural period of the elements composing the 20 ionized gas do not ily towards theY anode in a straight line but describe a curve, depending upon the following four factors-'the stress due to the main line potential, the temperature and pressure of the gas, the natural period of the ele- 25 ments composing the gas, and incidental interference by collision. r

In a gaseous electron discharge valve, the discharge cannot be stopped or extinguished where there are plane openings greater than the open- 30 ings in the mesh which, of themselves, are small enough to allow a sheath of positive ions to close the openings on application .of a negativetension. If the grid is simply placed across the tube above the cathode, then, even if the space be- 35 tween this element or grid and the walls of the chamber is very narrow or small in its diameter,

` with enough space between the inner wall of the tube or vessel and the periphery of the metallic structure or element sufficient to prevent, upon 40 expansion of the element, the cracking of the tube or vessel, grid control would be lost. However, by attaching a skirt to the periphery, of such length that the depth of the passage between the periphery of the element and the inner surface oi 45 the tube would be reduced electrically, then for control purposes, the opening would not be electrically greater than the structurally small openings in the grid itself.

By elongating or deepening the opening through which the discharge passes, the application .of the negative potential'wll effect electronically the size of the opening. This again, may be accomplished byv placing a channel member in that part of the discharge stream, suiliciently long so that the drop between the entrance and exit to the channel is great enough to place a negative charge thereon to extinguish the arc,

If the channels are not long enough to completely extinguish the arc with a critical charge placed thereon, a modulatingeiect may be produced by varying the negative charge placed thereon, and the arc stream varying its intensity and resistance with the variations of the negative charge on the channel, providing, however, the channel is insulated from the cathode proper.

I have made a further discovery; that if the ion sheaths are made so thick that they nearly touch, making the arc path very narrow, the arc may be reduced. However, by completely enclosing the cathode, so that there is only one small orifice, the enclosure being of conductive material, and this enclosure biased positively with respect to the cathode, geyser takes place at the opening, or openings, if more than one opening, depending on the emission at that point and, for all intents and purposes, that geyser becomes a new cathode with respect to the anode. If this opening is continued with a channel-like structure, the arc will beextinguished if a negative tension is placed upon the channel, again providing the channel is insulated from the grid or cathode enclosure proper. However, if the entire structure is conductive and connected to both the channel and the enclosure, and the negative charge placed thereon, the arc will be extinguished, always providing that the channel is long enough so that, though its mechanical size is great, the electrical size of the opening is reduced to approximately a circular opening not more than a thirty-second of an inch in diameter, or completely enclosed. Then again, by placing the geyser or concentrated arc within a confined area, variations in magnetic, negative electric, or negative electro-static density, within the center of the helix (see #27 Fig. 8) produce further concentration in the arc discharge.

In this geyser tube (a modification of my elongated opening grid arc discharge tube, Serial No. 591,911) the elongated opening is made of insulating material or of metallic material and insulated from the grid proper, and having wound about its outside surface a coil which is connected to the secondary of a transformer or to a source of direct current. The current flowing through the helix will cause the concentration or dispersing of positive ions from within the opening. The proper combination of both the negative electro. static field, the negative electric eld, and negative potential on this opening, tends to constrict or wholly stop the iiow of the discharge through this opening or channel. A positive charge or electrostatic field will tend to clarify and aid in speeding the discharge on its way between the cathode and anode.

I have found in electron arc discharge devices that the ionized molecules of gases have a definite period or wave length. In every element the Wave length is different; therefore, the passageway through the aforementioned channel must be either longer than the wave length of the ionized gas to be controlled, or a passageway long enough, with the addition of a negative charge or field, so that the size of the opening, after electrical constriction, is great enough to control the ionized gas or arc discharge.

I have found, in vdischarge tubes used for illuminating purposes that, by increasing the frequency of the electric supply in or to the tube, the efficiency of the tube is increased with the increase in frequency, and the tube gives more illumination and runs cooler.

A long tubular envelope, containing a long metallic tube or channel used as a grid, would act as a controlled grid leak tube, providing the length of the grid was sufficient to produce the effect referred to hereinbefore. The length of the tubular grid depends upon two factors, namely, the internal diameter of the tube and the space between the outer grid Walls and the inner walls of the envelope. By the channel" I mean an artificial closed course or conduit, as a tube, regardless of cross sectional shape or length.

This exemplifies the phenomenon that is my discovery, which I call the Baruch effect that, when an orifice in a grid is so large as to produce a leak so that control of the arc is lost, it is possible to overcome this condition by elongating the orifice with a channel member long enough to reduce the size of the orifice electrically, thereby increasing the resistance of the ionic and electronic fiow, making possible the overlapping or touching of the positive ionic sheath produced by a negative charge on the grid, thereby stopping the arc.

The object of having a large orifice in the screen is to reduce the drop within the tube itself when in operating condition; in other words, when the current is flowing through the tube the grid is positive or swings free, whereas, in tubes having close-meshed grids totally enclosing the cathode mechanically, when it is desired to keep control voltage low, the fine mesh causes considerable drop which is often two to three times that of a gridless arc discharge device. Therefore, the advantage in having large mechanical openings in the grid, which become smaller electrically, owing to the depth of the orifice in comparison to its diametric area, when a negative charge is placed on the grid and that it allows for reduction in voltage drop within the tube and permits higher currents to be carried without excessive heating of the grid element, and increases efficiency.

The operation of my invention is as follows:

Figure 1 shows a tube of my invention, with sections a, a', with envelope I, cathode 2, mercury 3, anode 4, anode lead 5, cathode leads 6, 6', grid 1 with channel 8, and elongated walls 9, 9', and grid conductor l0, and space ll.

When cathode 2 is heated by electrical source 2', mercury 3 forms a gas in space Il, and the electronic emission from the cathode ionizes said gas. Though there is a positive potential on anode 4 from the main source of supply and the negative lead connected to cathode 2 of high potential from the same source, no current will flow through grid 1 or through channel 8 thereof or thro-ugh the zone between 9 and 9 thereof and the inner wall of the envelope I, (because of my discovery hereinbefore stated) the path beingy so long that resistance is too high for the current to flow. However, a positive charge, placed on the grid structure 1, will cause the current to flow between the cathode and the anode. If direct current is flowing between these two elements, it will continue to flow even when the positive charge on the grid structure is removed. If alternating current is used, a positive charge will have to be applied at the beginning of each positive half cycle or any part of the half cycle. However, the removal of the positive charge and the placing ofa negative charge on the grid extinguishes the arc or discharge. Starting or stopping can be accomplished at any point of the cycle, or at any interval, depending upon the lil@ liti

speed of application of a positive or negative charge to the controlling means.

Figure 2 shows the bottom part of the grid 1 and the opening of channel 8, where it connects on its periphery of 9, 9'.

Figure 3 shows a solid member 1', which can be substituted for the bottom in grid 1, and which, instead of having one hole 8, may have three holes, 8', 8, and 8"'. Both these formations can be used in Figure 4.

Figure 4 is constructed with a part of the envelope I" made of copper, with I" being connected to I and I' at b and b' with a Housekeeper seal. In this tube, by reason of the filament or solid cathode 2, no splashing takes place, nor do any mists occur, so that there is no continuous condensation between the mercury 3 and the copper wall I of the envelope I when the tube is in operation. Number Il is the channel, as represented by the same number in Figure 1.

Ihs modification, with the exception of a solid cathode, is similar to the construction of Slepians tube, Patent No. 1,731,687. The grid in his tube is inoperative because the splash from the pool f cathode and mist caused thereby, places a coating on the envelope between the cathode and the grid, rendering the grid inoperative. Figure 4 shows that I accomplish what Slepian failed to do. zone which is usually found between the grid and the walls of the vessel which is not subjected to the controlling influence of the grid. It thus permits conducting particles, such as electrons, to slip past the grid without coming into the region of the positive controlling action of the same. Mydiscovery and invention makes the so-called Zone controllable, and this use of a solid cathode prevents the mercury lm forming a short between grid and cathode.

The difference between Slepians construction and my invention is, primarily, that I use a solid cathode instead of a liquid cathode. The channel 8 in the grid, if made according to my specification, renders the tube operative and, at the same time, reduces the drop. The change from a pool to a solid cathode, in this structure, is fundamental and radical in itself, and results in making an impracticable and inoperative construction, by this change, operative.

The skirt hereinbefore mentioned may form part of the sides or walls of the tube and be connected to the screen grid itself, or the screen grid mesh may be so bent or shaped along the sides of the tube as to form a skirt.

Figure is an other modication of my invention, where I2 is a partition and a part of the envelope I, inverted cone-shaped in structure, with the grid plate 1 fastened to the bottom and extending up on the outer walls of the cone I2, and 8 is the channel through plate 1 extending upwards toward the anode d, electrically connected and part of 1. y

My tube, shown in Figure 5, operates as follows:

The lament 2 is heated lfrom source 2', through leads 6 and 6'. The heated lament vaporizes the mercury 3 and ionizes it by its electronic emission, lling the space II. Anode 4 is connected through lead 5, conductor I3 with terminal I4, gas lled illuminating` tube I5 through opposite terminal I5, to conductor ,of alternating current or direct current main I1. The other conductor I1' of the supply connected to conductor I8, through iilament lead 6', filament 2 and leads 6, I9 and 2 0, to source of alternating current 2|, conductors 22 and 23 to grid 1.

Slepian refers to the elimination of a When the cathode 2 is heated to emission, it ionizes the mercury vapor Within .the space Il, and when positive potential from alternating source 2| is impressed on the grid 1, the critical positive potential frees the path up through channel 8 and allows the current to flow through the tube. When the anode il is connected by conductors to i1, and the opposite side of the main source of supply connected to cathode 2 through conductors 6', I8 and Il', the current ows through the tube when positive potential is placed on the grid l. The arc will be extinguished when the positive is withdrawnl and a critical negative potential placed on the grid approximately 5 volts or more, depending upon the size of the opening in the grid and the anode voltage.

Furthermore, illuminating tube I5 may be deleted from the circuit and conductor I3 connected directly to the conductor I1. The tube is still operative 'as illuminating tube I5 is placed in the circuit merely to show that the high frequency produced by my invention, with either alternating current or direct current on the illuminating tube, increases its efficiency by causing the illuminating tube to give more light and run cooler with less current consumption than with a low commercial frequency.

Figure 6 is the same as Figure 5, except that the skirt of the grid plate l? extends up inside of the cone-shaped interior I2 of envelope I.

Figure 7 exemplies the phenomenon of my discovery in its simplest form. In Figure "1i, the grid plate 1, extending up alongside of the walls of the envelope I, will act as an ordinary grid, having a small hole wherein the positive ion sheath can overlap and close the opening. There is a limit, however, as to how large the plane or circular area of the tube can be, so that its length will not be beyond dimensions reasonable for practical use. Under these circumstances, a circular area one-quarter of an inch in diameter is about the approximate practical size, though it may be larger under special conditions. The resistance offered to the discharge flow between cathode 2 and anode 4, by reason of the drop within the grid itself between the discharge path entrance and exit, is suflicient to prevent or extinguish the arc when a critical negative charge isplaced thereon. This same result is also accomplished by a negative electrostaticmeld and a negative electric field, with means herein claimed and specied.

In Figure 8, the grid plate 1, in order to make a complete enclosure, excepting for elongated opening 8 over the cathode Il, is made in the form of a skirt which extends down over the elongated stem 24. By reason of my discovery of the phenomenon hereinbefore set forth, by making the length of the skirt of 1 over the extended stem 2li, the formation of a leak between the skirt of 1 and the stem 24 in the zone 25, isV

prevented. The larger the area of the zone 25,

Athe greater must be the length of the skirt in relation to the stem. The same relation applies to any skirt or elongation of the grid where it forms part cf a normal, uncontrollable` zone.

One of the features of this invention is the geyser effect produced in the elongated opening 8, forming a secondary cathode, by reason of the bombardment of the concentrated gas molecules and by the electrons when the grid is made positive, and the electron-emttive material forming the channel 8 itself. This bombardment produces a cathode of tremendous carrying capacityvery much greater than the primary cathode, which would be instantly destroyed if it had to carry the current which the secondary cathode now will carry. Channel 8 is insulated from skirt l by insulator 26, made of metallic material enclosed with a coil 21, one end of which is connected to lead 28 passing through a section of envelope I, the other end of 21 grounded on metallic channel 8 at 29, and connected to conductor 38 passing through a section of envelope I.

With this modification lof my invention, a negative or positive potential of critical value of 10 volts positive or negative, connected to conductor 30, will start or stop the ilow of current passing through channel 8, providing, however, the same potential is placed on conductor 3| at the same time. A modulating current connected to conductor 30 through coil 21 and out through envelope l on conductor 28, puts a magnetic, electric and electrostatic eld in channel 8 if said channel is constructed of such material as will permit penetration of these forces, such as isolantite, porcelain, and the like.

When channel 8, as in Figure 8, becomes a secondary cathode, the negative lead from the mains to the cathode 2 must contain a currentlimiting resistance and a direct connection without resistance made from the negative main to lead 30.

In operation, when a critical positive charge is placed on the grid 1, and the main current being imposed on the anode and cathodes, the geyser eiect takes place in channel 8 which becomes a secondary cathode and carries the main current going through the tube, a portion of this being taken by cathode 2, within the limits of the resistance in its local circuit.

Having described my invention, what I claim 1. An electronic control switch, comprising an envelope, a space having a rarefled gas containing a metal vapor therein, an anode, a solid electron-emitting cathode disposed in said space, a perforated control grid structure the envelope co-operating to surround and enclose said cathcdc and having a tube like channel opening, said opening being so elongated that when a negative charge is placed on the grid, said openingwill decrease in size electrically.

2. An electronic control switch, comprising an envelope, a space having a rareed gas containing a metal vapor therein, an anode, a solid electron-emitting cathode disposed in said space, a perforated control grid the envelope co-operating to surround and enclose said cathode and having a tube-like opening, said opening being so elongated that when a critical negative charge is l placed on the grid an ion sheath closes the opening and the arc will be extinguished.

3. An electronic control device, comprising an envelope, a space having a rareed gas containing a metal vapor therein, an anode, a solid electron-emitting cathode disposed in said space, a perforated control grid structure the envelope cooperating to surround and enclose said cathode and having a tube-like channel opening substantially greater than the iine openings of said grid, said opening being so elongated that, when a negative electric eld is placed on the grid, the arc will not be extinguished, and the tube drop will be increased.

4. An electronic control switch, comprising an envelope, a space having a rarefied gas containing a metal vapor therein, an anode, a solid electron-emitting cathode disposed in said space, an

imperforated control grid structure the envelope co-operatingtg surround and enclose said cathode and having a long tube-like opening, said opening being so elongated that when a critical negative electrostatic field is placed on the grid, the arc will be extinguished.

5. An electronic control switch, comprising an envelope, having a rareed gas containing a metal vapor therein, an anode, a solid electronemitting cathode disposed in said envelope, a perforated control grid structure using part oi the envelope to completely enclose said cathode and having a tube-like channel opening substantially greater than the other openings of said grid, said opening being so elongated that when a critical negative charge is placed on the grid, said opening will decrease in size electronically.

6. An electronic control switch, comprising an envelope, having a rareed gas containing a metal vapor therein, an anode, a solid electronemitting cathode disposed in said envelope, a perforated control grid structure using part oi the envelope to completely enclose said cathode and having an opening substantially greater than the fine openings of said grid, said opening being tubular so that when a critical negative charge is placed on the grid an ion sheath closes the opening and the arc will be extinguished.

7. An electronic control device, comprising an envelope, a space having a rarefied gas therein,

an anode, a solid electron-emitting cathode disposed in said space, an imperforated control grid structure dividing said space in two parts thereby completely enclosing said cathode and having an opening substantially greater than any other opening in said structure, said opening having a. tube-like extension sufllciently elongated to increase the resistance of the discharge path between the cathode and the anode by decreasing the area of said opening electrically.

8. In an electronic control switch, comprising an envelope, a space having a rareed gas therein, an anode, a solid electron-emitting cathode disposed in said space, a perforated control grid structure and the envelope co-operating to completely enclose said cathode and having an opening substantially greater than the other openings in said grid, said opening having a tube-like extension suciently elongated to increase the resistance of the discharge path between the cath- 'ode and the anode by decreasing the area of said opening electrically, so that by applying a critical negative potential to the grid structure the arc is extinguished.

9. In an electronic control device, comprising an envelope, a space having a rareed gas therein, an anode, a solid electron-emitting cathode disposed in said space, lead-ins for said anode and cathode, an imperiorated control grid structure and the envelope cooperating to completely enclose said cathode, and having an opening substantially greater than any other opening in said structure insulated from said cathode, said opening having a tube-like extension sufiiciently elongated to increase the resistance of the discharge path between the cathode and the anode by decreasing the area of said opening electrically, when a critical negative electric eld forms an ion sheath in said tube-like grid structure to eX- tinguish the arc.

10. In an electronic discharge device,compris ing an envelope, a space having a rareed gas therein, an anode, a solid electron-emitting cathode disposed in said space, a control grid structure and the envelope co-operating to completely enclose said cathode and having no opening other than the tube-like opening for concentration of the gas discharge therethrough when a positive potential is applied to said grid structure.

11. An electronic arc discharge device, comprising a space having a rareed gas therein, a solid electron-emitting cathode disposed in said space, an anode, and a control grid structure forming part of the wall of the envelope enclosing said space, so that a critical negative electric i'leld applied to said grid structure will extinguish the arc.

12. A thermionic device comprising an electron-emitting cathode, an anode, a grid element having an elongated tube in said element, and an enclosing envelope, a gaseous medium within said envelope, said grid element structure and envelope co-operating to completely enclose said cathode, the apertures of said grid element having an area of such size that they are partially closed to the passage of electrons by sheaths of positive ions upon the application of critical negative voltage to the grid element.

13. An electronic control switch comprising a rarefied space containing a gas, an electron-emitting cathode disposed within said space, a control grid having an opening supplemented with an elongated channel, so that the length of said channel in said grid is sufficient to reduce the electrical area of said opening when said grid is subjected to a critical negative potential.

14. In a gaseous electric device comprising a vessel, a solid cathode, an anode, mounted in said vessel, a gaseous medium for conducting the current between said cathode and said anode, a portion of the walls of said vessel being composed of conductive material, and forming part of a screen grid separating the anode and the cathode, said grid having an opening' larger than the openings oi the screen of the grid itself, and a channel-like extension forming a part thereof.

15. An electronic control device, comprising a space having a rareed gas containing an alkali metal vapor therein, an anode, a solid electronemitting cathode disposed in said space, a control grid structure dividing said space in two parts and forming part of the envelope of said tube surrounding and enclosing said cathode and having a tube-like opening substantially greater than the other ne openings of said grid, said tubelike opening being so elongated that when a negative charge is placed on the grid, said opening will decrease the size electrically.

16. The method of controlling the duration of an arc discharge in a gas, which consists in rendering conductive the arc path between two electrodes, restricting the cross sectional area of the arc path, and applying a negative electric field to the restricted area of the arc.

17. 'I'he method of controlling the duration of an arc discharge in a gas, which consists in rendering conductive the arc path between two electrodes, restricting the cross sectional area of the arc path and surrounding the arc discharge at the restricted area with a negative electric field of a potential high enough t'o form a closed sheath of positive ions to extinguish the arc.

18. An electronic control device comprising an envelope, a space containing a rareiied metal vapor therein, an anode, an electron-emitting cathode and two control grids electrically enclosing said cathode, each one of said grids making a partial enclosure of said cathode.

19. An electronic control device comprising an envelope, a space containing a gas therein, an anode, an electron-emitting cathode, and two grids electrically enclosing said cathode, each one of said grids making a, partial enclosure of said cathode for controlling the operation of the device.

20. The method of controlling the conductivity

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