US1893638A - Gas discharge relay - Google Patents

Description

Jan 10, 1933. J. M. SCHMIERER GAS DISCHARGE RELAY Filed Nov. 6. 1930 2 Sheets-Sheet Y INVENTOR J'aannes Hic/MY/ Schin/eraf ATTORN EY Jan. 10, 1933. l J. M, scHMlERER 1,893,638

GAS DISCHARGE RELAY Filed Nov. 6, 1930 2 Sheets-Sheet 2 :IIIIIIII'IIIIIIIII l INVENTOR Johannes /V/c'a e/ 5c/Innerer ATTORNEY Patented Jan. 10, 1933 Unirse sra'rss Partnr oiirlicel v(1l-AS DISCHARGE RELAY npncation ineaA November e, 1930, serial No. 493,524', and in Germany November 7, 192e.y

My invention relates to electric relays or devices by means of which a relatively small `amount of electrical energy may be made to control large quantities of power and more particularly to relays of the electric discharge t e.

y'Plhe well-known vacuum tubes, suchas used in radio foj'the purpose of producing oscillations, an'lific'ation, or rectification, are reproduce comparatively greater changes in plate current.' These tubes, which operate with a pure electronic discharge, have, how! ever, the drawback that they require twoA diii'erent sources of operating currents; that is, a sourcel of4 potential for sup lying the electron discharge current throug i the tube and a further source of current tor heating the cathode electrodeand maintaining it at a high electron emitting temperature.

In view of this drawback, it has been proposed to use glow or gas discharge tubes, in place of pure electronic vacuum tubes; that is, tubes which contain a gas'ot definite composition and pressure and which do not require a heated cathode. Such gas tubes, however, have not gone into commercial use to any practical extent, on account ot a number of drawbacks, such as rapid and early disintegration ot the cathode material by ionic bombardment and the deleterious action of occludcd gases in the cathode material, which mal-:e the tube operation both unstable and unreliable.

It is, accordingly, an object ot my invention to provide a novel gas discharge tube of the type referred to, which is devoid of the above mentioned drawbacks and which op.

erates on a single supply voltage and, thus, has numerous advantages over the customary electron vacuum tubes.

A more specific object ot my invention is to provide a novel gas discharge tube, which exhibits increased stability of operation and which allows an easy and effective control of the discharge current, in accordance with small input currents or potentials.

These and further objects ot my invention will become vapparent from the following de- 50 tai-led description, made with reference to the lays in w '1ch small changes in grid'potential j accompanying drawings, in which-I have illustrated some embodiments of'my invention. I wish it tobe understood, however, that the description andthe drawings are'intended to be illustrative only of the broad inventive 55 principle which may be embodied, as 'will become obvious in many modifications -'coming within its broad and most comprehensive scope, as expressed in the appended'claims.

In the drawings Y Tf1 60 'Figure 1 illustrates a curve'explanatory of the theoretical operation-lof, a gas discharge tube relay, constructed in'acc'ordanceV with my invention. y f Y Figure 2 is a simple electrical circuit :from

`which the data for the curve shown in Figure l has been plotted. l Y

Figures 3 and L show circuits,in accordance with my invention, in which my novel gas'discharge tube may be used as an amplifier.

Figure 5 shows another modification of the circuits shown in Figures 3 and 4;

Figure 6 is similar to Figure 3, having an asymetrically arranged control electrode in respect to the vmain discharge electrodes.

Figures 7 and 8 illustrate'novel multiple discharge tubes, according to my invention', in which two electrode systems have been combined for the purpose of cascade ampliiication in a single tube. y y

Figure 9 shows a cross-section of a tube, embodied in my invention, by which the character of the operating characteristic may be varied, as desired. l

Figure l() shows a further way of changing the operating characteristic of a. gas discharge tube, in accordance with my invention.

My invention is based upon a form ot gas discharge which essentially differs from the well-known glow discharge occurring between a cathode and anode electrode disposed in a gaseous atmosphere. The discharge utilized in accordance with my invention occurs only at the very low intensities of operating current, as compared to the ordinary glow discharge, as known in the art. This discharge, as utilized in accordance with my invention, will hereinafter be termed ante-glow dis-A charge, as it occurs prior to the glow disnomenon maybe as 5follows :.Due tothe close-v iness4 of the ltwo electrodes-,to each other andent dischar e without the-'common negative glow is pro uced and maintained. `With this kind of gas discharge, which I liave'lcalled'- anteg-lv discharge, therelis `a 'luminescent lm adjacent to the anode electrode, the

luminosity or brightness of which-gradually' decreases` as vit approaches thecathode electrod'e;l A possible explanation ofthis vphe- Vtthelow'voltage operation, the electrons do not gain asuicient velocity to ionize the .gaseous moleculesgbycollision, butr the ve- ,locitys just sucientfto create theemission of light rays.' f

Figures. 1 and: 2 willvexplainthese phe-z y l nomenafurther.

.g`as o f Iproper natureand pressure, such as, for

instanc e`withfa mixture of three parts of*v neon and one part of helium, at a. pressure of l0 millimeters H yDisposedWithinthe vesselgfvE are ,-aatho e electrode c vand an anode electrode a, both having the -shape of a spirally wound wire, arranged juxtaposed to y.; leach O ther. The cathode and the anode elecpotential, such as battery B in series with aA protective resistance w. By varying the volttrodes are connected to a source of operating age applied to the tube electrodes, such as by means of a -potentiometer p andobserving the variationsin output'eurrent, a graphie showping of the operating characteristic, .as sche` matically shown by Figure 1, may be plotted fromthe values thus obtained. "This curve .illustrates the discharge current passing through the tube plottedas a function of the 1 voltage e ofthe operating source- B. .From this curveit is seen that by increasing the voltage from zero to positive values, through the range the discharge current increases in substantially a direct proportion, according to a sloping curved or almost straight line. This gradual increasecorresponds to the ante-glow operating range (a2 according to Figure l) I have discovered that, in order to obtain a sufficiently broad range of anteglow of the tube for utilization, such as for use ofthetube as an amplifier or the like, the

distance of the electrodes when utilizing gases of the nature mentioned hereinbefore, should not be' greater than about 5 millimeters, or, in general, approximately not morethan 10 times the amount of the mean i free path of the particular gas used'. A possible explanationof this ante-g1ow, as alreadypointed out, consists in :thepredominance of electrons over the ions during this condition, Whereas, during the actual glow discharge, the number of ions will be considerably larger than the number of electrons present within the tube. This makes it obvimains substantially below theamount of the ionizing electrons. Then, if the voltages increase beyond the limiting point P of the ,ante-glow range, the number ofionlzmg electrons will have accumulated to such an extent that suddenly the ions will predominate over the electrons and, thus, bringl about the normal glow discharge of the tube. As is well known, thev mean-free-pathdis a, conlstant for agiven '-gas, `being also'dependent on the pressure of the gas and is the ,mean free distance through which one electron in such gas` has to .travel to assumevsufficient i ,.jvelocityftozproduce ionization by collision Referring to Figure 2, I haveshowna ves- 3 i selc, such as aglasstube which is filledv with a with a gas molecule.

The density ofthe ante-glow? current is considerably smaller than the densityA ofthe ordinary glow discharge eurent and, accordingly, the surface -of the cathode has to be much larger than in an ordinary glow discharge tube'carrying an equalload. lSince, furthermore, in contra-distinction to the common glow discharge, the discharge isconcentrated upon'that part of the cathode surfac'efrom which the electrons are enabled to pass through the anode over the shortest distance, it( is necessary to make the anode con- "siderablyy larger than would be the case with an ordinary glow dischargetubc. Otherwise, large portions of the cathode would remain unused.

It is, therefore, not suiiicient that the distance between the cathode and anode be small at a single point only, but I have discovered that it is necessary to provide cathode and anode electrodes of such construction that a maximum number of points on the cathode 'the starting voltage and the extinction voltage have the same value, while with the common glow discharge the starting voltage is considerably'higher than the extinction voltage. Thus, ifthe terminal voltage of an ante-glow. discharge tubeiscincreased as:

dropped below =.its starting voltages The starting voltage and extinction volta-gewithf. -in the ante-glow operating range; of :the tube,- on the other-han ,have exactly the same value correspondingto .a .very lowcurrent intensity, whereas,.withfthe ordina-ry glow..

discharge, the .startingvoltageis consider- 'iably vhigher than the. extinction. voltage, the

latter correspondingto a denitevalue of the current intensity.

I have discovered that no,.disintegration process takes place in -ante-glo;w gas dis- 2oHeharge tubes which` -havebeen operated during a period of y1,000 to- 3,000 hours, nor could any essential lchange .in the operating characteristicbe observed, so that the main draw.- baeksof glow .discharge` or gas discharge 'have been overcome This may probably be explained .by the `absence'of any considerable ionized gaswhich ordinarily bombards the cathode.

`In accordance with tlrepresent invention,

`II providemeans-for controlling the anteglow discharge current primarily in the form of a further electrode,-such as a a grid electrode similarfto` the common electronic vacuum. tubes.- As is well known, inordinary gas fdischarge -or glow .dischargey tubes, -in which the discharge is .composed primarily or exclusivelyZ of electric .,ions, great difficulties are .experienced .in controlling the; discharge current, such-as by means-of a grid. electrode.

In fact, such tubes have, up to the present,v

been .used merely for producing-.akind of trigger action, which is equivalent to a switchingoperation It has notbeen possible heretofore. to construct gasA discharge tubes in such a manner as to enable a gradual and faithful control of the discharge curT rent, in-accordance with the variations of the input energy.

When, however, a tube is operated in accordance with the present invention, operating within the range of ante-glow?? as described, I have discovered that such tubes may be as easily and effectively-controlled as is the case with the ordinary high vacuum electron tubes, as used for radio and other purposes. This may be explained by the presence of electrons, rather than ions, of which the ante-glow current is primarily or entirely composed, as pointed out above, whereby. as effective and easy a control is possible as with pure electron tubes. This entails the possibility of various constructions and modifications of ante-glow control tubes, a few of which I have illustrated ini the drawings Figures/3 to l0.

anode@ an d. coupling resistance WC tocathode Returning to Fig-:2,1 have shown agridi electrode g in the 'form-of a solid member or r cylinder, arranged outside the anode and cathode.electrode.v

Referring to -Figure .3, thisI illustrates: an ante-glow. tube with two flat-electrodes a, c and a control-grid-g arranged between such electrodes., The inputenergy lshown atI, as,.: for instance, l.weak telegraphic signals, voice currents, or thelike, is applied to the grid and cathode of the tube and a suitable biasing bat-- tery,:\vhich may bepositive or negative,may also bel-provided, if found necessary. The current variations thus applied to the grid will occur in van vamplified form in the output circuit-ofthe tube and may. be utilized in adesiredmanner, such as, for instance, by means of a telephone or loud speaker t.

Referringv to Figure 4, this isa .similar'ar rangement. to Figure 3, the only difference res-iding'in :the conneetionofthe input cir-` cuit earryinginput or.controlcurrents be- 1 tween the anode Yand grid electrode, in placey of tothe gridaand cathode.. .Y

In Figure 5 I have shownanalternative arrangementin awhich the discharge tube is provided withtwo grids gland g2, to which the input circuit is connected-.z

According tol Figure 6, which is essentially? identical-to Figure 3, the grid electrodezg is SOL sse

arranged a'ssymetricallyV between the cathode f i istic of the tube for using the tube for definite purposes, such as either for amplification for rectification, or'also asan oscillator. .It is,

furthermore, possible to combine two 0r moreelectrode systems -within a single vessel, such asvshown by the multiple tube circuits of, Figures 7 and 8. According to Figure 7, I have shown a tube with .two electrode svstems; that is, a common cathode and two individual anodes al and a2 and a grid electrode g. A coupling resistance IVG isarranged between cathode and anode al, which serves to provide a suflicient coupling potential produced by the discharge current between cathode c and the first anode al, whereby. a

second amplification in the anode circuit of the anode a2 is obtained, which latter includes the. translating device t. Gg is a blocking condenser for blocking the potential of the operating battery B against the grid electrode.

Figure 8 is asimilar circuit'to Figure 7, the only difference being that cathode and anode electrodes have been exchanged. Two cathode electrode-s C1, C2 cooperate with anode a. W'hen a voltage is impressed across gridv g and cathode C2 current flows over C2. ',Ihe drop across resistance WC controls the current iow to the receiver t.

As a gas filling I preferably use a mixture of neon and helium with or without an addition of rare gases, at a Apressure of from three to thirty-live millimeters Hg. The elec-` small electrode distance, the electrodesmay,

in general, be constructed with the surfaces arranged parallel `and opposite each other. If, however, for obtaining a diiferent operating characteristic in'respectto both directions of the current How, itis desirable to make the surfaceotl one electrode considerably 'largerthan the other electrode, this can, for instance, be obtained byusing a solid f 251fcathode-.of large.' surface and ivan anode consisting 'of a -Wire'net and, accordingly, presenting a smaller surface and arranged-'parallel to the cathode, such as shown in Figure 9. The same e'ect maybe obtained by using \`concentric anode and .cathode electrodes of different diameter, as illustrated inV Figure 10. 1

I wish it to be understood that I do not desire to be limited to the exact'detail 4of construction as-shown and described, for obvious modifications will occur to a person skilled inthe art.

What I claim is: 1. In a system for relaying weak electric 40Tcurrents, an ionic tube, including a pair of cold electrodes close together, means for impressing a voltage across said electrodes, of a value such as to maintain the tube in a state of ante-glowdischarge and control means 4for introducing current variations in said discharge current, whereby said discharge current is an amplification of variable control currents applied to said control means. 2. An ionic tube, including a pair of cold electrodes close together, means for impressing a voltage across said electrodes of a value such as to maintain said tube in a state of ante-glow discharge and a control electrode arranged to influence said discharge.

3. An ionic tube, including a pair of cold electrodes close together, means for impressing a voltage across said electrodes, of a value such as to maintain said tube in a state of ante-glow discharge and a grid electrode arranged between said cold electrodes.

4.-. An ionic tube, including a pair of cold electrodes, means for impressing a voltage across said electrodes, said voltage and the spacing ofsaid electrodes being of such value as to maintain the tube in a state of anteglow discharge and a control'ele'ctro'de forl electrodes, arranged close together and parallel to each other, means to impress an electric voltage across said electrodes, said voltage and the spacing of said electrodes being of a value such as to maintain said tube in a state of ante-glow discharge and a control electrode for influencing said discharge.

7. An ionic discharge tube, including a pair of cold electrodes arranged parallel to cach other at a distance less than ten'times the mean' free path of the gas included in said tube, means for impressing an electric voltage across said electrodes of a value such-v as to maintain said tube-in a state'ofante-glow discharge, and a grid electrodearranged becharge. v

8. In an electrically controlled system, l 'a control circuit, a circuit arranged to be controlled by said control circuit, means-interposed between said circuits comprising a gas discharge tube having a pair of cold electrodes, series means to said circuit to be controlled impressing a predetermined voltage across said electrodes of such value `as to maintain the discharge of said tube in a state tween said electrodes for controlling' said disof ante-glow, and a control electrode connecty ed to said control circuit for influencing said discharge. y

9. In an electrical control system comprising a control circuit, a. circuit arranged to be controlled by said control circuit, means interposed between said circuits comprising a. gas discharge tube having a pair of cold electrodes, series means to said circuit to be controlled for impressing a predetermined voltage across said electrodes of such value as to maintain said tube in a state of ante-glow discharge, and a grid electrode between said cold electrodes connected to said control circuit for influencing said discharge.

10. In an electrical circuit arrangement, a

gas discharge tube including a pair ot cold electrodes, a circuit tor impressing a predetermined voltage lower than the glow discharge ignition voltage across said electrodes, a control. electrode 'for influencing said disch arge and a control circuit connected to said control electrode for producing corresponding variations oi' the discharge current of said tube.

11. In an electrical circuit arrangement, a gas discharge tube including a pair of cold electrodes arranged parallel to each other, a

circuit for impressing a predetermined Voltbetween said electrodes, the gas pressure, age lower than the glow discharge ignition spacing of electrodes and voltage maintaln- Voltage, a grid electrode arranged between lng the tube in an ante-glow.

said cold electrodes, a control circuit connected to said grid electrode for influencing said discharge for producing corresponding variations in said first circuit.

12. In an electrical circuit arrangement, a gas discharge tube including a pair of cold electrodes, a circuit for impressing a predetermined Voltage lower than the glow discharge ignition voltage across said elec. trodes, a grid electrode arranged intermediate said cold electrodes7 a control circuit connected to said grid electrode and one of said cold electrodes for influencing` said discharge and producing corresponding variations in said first circuit.

13. In an electrical circuit arrangement, a gas discharge tube including a pair of cold electrodes, arranged parallel to each other and at a distance less than ten times the mean free path of the gas included by' said tube` a circuit Jfor impressing a predetermined voltage lower than the glow discharge ignition Voltage across said electrodes, a grid electrode arranged between said cold electrodes and a control circuit connected to said grid electrode and one of said cold electrodes for influencing said discharge and producing corresponding current variations in said first circuit.

14. In an electrical circuit arrangement, a gas discharge tube including a pair of cold electrodes. of different surface and arranged parallel to each other, a circuit for impressing a predetermined voltage lower than the glow discharge ignition voltage across said electrodes, a grid electrode arranged between said cold electrodes and a control circuit connected to said grid electrode and Vmeters, a circuit for impressing a predetermined voltage lower than the glow discharge ignition voltage across said electrodes, a grid electrode arranged between said cold electrodes and a control circuit connected to said grid electrode and one of said cold electrodes for influencing said discharge for producing corresponding current variations in said first clrcuit.

16. In an ionic tube having gas at a predetermined pressure, a pair of electrodes, the i distance from every point of one of said electrodes to the other electrode being uniform, means for applying a predetermined voltage In testimony whereof I aliix my signature.

` JOHANNES MICHAEL scumlsmsk.

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