US1935846A - Gasfilled incandescent cathode discharge tube - Google Patents

Description

Nov. 21, 1933. HQLST 1,935,846

GAS FILLED INCANDESCENT CATHODE DISCHARGE TUBE Filed April 5, 1928 Patented Nov. 21 1933 um rsn P TENT oFF cE 5, {192a, serial No. 267,623;

and in thelietherlands April 11, 1927 13 cl ims. (01'.- 115 363) *This' int ent'iorirelates to anielectrical device, more'particularly' adapted for use in rectifying mitlng currents, incandescent age between the electrodesim determined by $118 Voltage 5 betweem Hid incandescent cathode and 8 point lylhg "the-amide and by the tente -ln order to=- limlt-as much as' possible the loss of energy by thaulflfliary discharge,

a may between the auxdiary e "and' -the anodey 'sald" resistance '30" serving to limit to a minknumtheeurrent flow ing' between the auxiliary cathode the anode. The invention aflordsmial advantages with discharge tubes oi the said klnd ior greatcurrent intensities, at with" suchadlscharge tubes,

85 due to the neutralization ot the anode drop, the

lessor energy inthe discharge is diminished: by an amount almost equal the productfioi the anode-drop andthe-current-intensity." r

fllieddisoharge tubesior-illuminating-purposes are knownalready in-whichateachend-of thetube, an anode is amnged; sm-rounding an electron emitting cathode. 1 In suchwase "the cathode is directly connected electrically to the surroundinganode, so that no discharge-between these electrodew is produced. 1 The obiectot this construction is-to permit the current to both directions with the same ease.

A w rm adeviee mama:

to" the invention has the feature that the electron emitting'auxiliary cathode is in: smated from thear'iode. Prefefablythe electron emitting cathode is an "lficande scible cathode; In an; exceptionally suitable rjnqdepf construction the cathode isarran'gedwithin'a hollow body, the

-56 anode bein gplacedbetoreancpeniend of this it may be even bodyiand lnsulated therefrom. It is clear that in thisease the hollow body forces the ions to remain inhtheneighborhood of the anode. To leaverthe hollow body they must" pass the anode. By forming the hollow bodyotmetal and providing itewith a pole wire, a potential differing from that ofLthe anode may be givento the body, in order toiurther direct the ions to the anode. Tha anode:may be perforated. in suitable manner; for instanceit may be made of gauze, to enablethepositive ions produced by the auxiliary dischargeto enter easily into the main discharge I'he invention will be more clearly understood by reierring: to theaccompanying drawing which represents, by way of example, a discharge tube include'd'in alcircuit-iarrangement for the rectifyingof alternating current.

.1 The discharge tube l comprises an incandescent cathode'2 and an anode 3. An auxiliary'incandescent cathode 4 is arrangedbehind the anode '3 in; the interior of the hollowbody 5 which forms one structure with-the anode 3 but is electrically insulated therefrom. The anodemay consist of a; gauze or perforated wall which allows positive ions produced by the auxiliary discharge to enter intothemain-discharge path. The cathode 2-is connected to one end otthe secondary 6 of a. transformerHthe-primary otwhich is not illustrated. The Lotherend of the secondary winding is connectedto the-anode 3. The cathode 2 and theauxili'ary cathode 4 arebroughtuptothe required temperatureby current supplied from transformerwindings 7 and- 8. The auxiliary cathode 4 isconnected to an intermediate point of thesecondary 6. so that between the electrodes 41nd 3 'thereis only a comparatively small potential diflerencei The hollow body 5 which is electrically insulated from the anode, may be brought to'athe required potential by means of a connection 9. V v v Asthe'bodyfi isto'direct the positive ions from the auxiliarycathode 4 to the anode'3, its potential mustbe higher. than that ofrthe cathode 4. As a rule, itsufllces that the potential of the memher-babe but afew volts higher than the potentlal ofcathode 4, although under circumstances higher than the potential of the anode 3.

-"To obtain'the proper potential forthe body 5, the lead 9 may be connected to a tap of the transformer winding 6 which lies between the left ,hahd -terminal'o! the transformer and that point to which the cathode 4 is connected. Or a storagebaitt'ery maybe connected betweenthe body 0 5 and the auxiliary cathode 4. In both of these cases an alternating potential is applied to the body 5.

If it isdesired to apply a directpotential to the body 5, the lead 9 is connected through abattery to the middle point of the secondary wind ing of transformer 8.

In any case, it is preferable to limit the current.

flow between the body 5 and the cathode 4 by providing a resistance in the, circuit branch leading to the body 5. The battery potential in the above cases is preferably of the order of 8 to 10 volts.

WhatIclaim is:

1. An electric discharge device compris'ing a gasfilled envelope, an anode, and an incandescible cathode therein, means to neutralize the anode drop, said means comprising an auxiliary incandescible cathode disposed in the vicinityot the anode, and insulated therefrom, said auxiliary .cathode .having an electron emission of such magnitude to. produce an auxiliary discharge between said auxiliary cathode and said anode to. furnish a suflicient number of positive ions to neutralize the anode drop. l

2. An electric discharge device comprising a gasfllled envelope, and anode, and an incan-r descible cathode .therein, means to neutralize the anode drop, said means comprising an auxiliary incandesciblecathode on the far side of the. anode from the main cathode and having an electron emission of sufiicient magnitude to pro duce an auxiliary discharge between said auxiliary cathode and said anode to furnish a sunlcient number of positive ions to neutralize the anode drop.

1 3. An electric discharge device comprising a gasfilled envelope, an anode, and an incandesci: ble cathode therein, means to neutralize the anode drop, said means comprising an auxile .iary 'incandescible cathode spaced, from said anode at a distance shorter than that between the main cathode and the anode, and a screen on the far side of the auxiliary cathode from the anode, and having a lead wire sealed through the. envelope. Y

, 4. An electric discharge device comprising an.

envelope, an'incandescible cathode, an auxiliary cathode, a open-ended, hollow metal body surrounding the auxiliary cathode, a perforated anode disposed in front of; the open'end of the hollow. body and insulated therefrom as well as from the other electrodes, and a lead wire from said body sealed through said envelope, said electrodes being disposed in'said-envelope. g

5. In combination an electrical discharge.device, comprising a. sealed gasfllled-envelope, an

anode, an incandescible main cathode, and an auxiliary cathode therein, said auxiliary cathode being disposed at a shorter distance Irom..the

anode than the main cathode, and'a sourceof electric supply connected .to the electrodes Ior causing current flow between the main cathode.

I and theanode and between the auxiliary'cathode and the anode, the last-mentioned current having a value sufflcient to produce ions substantially neutralizing the anode drop of the discharge between the main electrodes.

6. In combination, for rectifying alternating currents, an electrical discharge device, comprising a gasfilled, sealed envelope, an anode, an-

incandescible main cathode, and an auxiliary cathode therein, said auxiliary cathode being dis: posed at, a shorter distance from the vanode han the main ca e n de circuit comp i n main discharge;

a source of electric supply across the main cathode and the anode, and across the anode and auxiliary cathode, and means for limiting the current transmitted between, the anode and the auxiliary; cathode to, a value at which the-number of positive ions is suiiicient to" substantially neutralize the anode drop of the discharge between the main electrodes.

7. In combination, an electric discharge device comprising ananode, an incandescible cathode, an auxiliary incandescible cathode inthe vicinityoithe anode, a gasfilled envelope for the electrodes and a circuit comprising an electric supply source, and means by which current is transferred between the main cathode and the anode and between the auxiliary cathode and the anode, the last-mentioned current having a value sufllcient to provide for ions substantially neutralizing the anode drop of the discharge between the main electrodes.

'8'. In combination, anelectric discharge; device comprising a gasfilled envelope, an anode, an incandescible cathode, and an auxiliary incandescible cathode inthe vicinity ofthe anode dis, posed in-said envelope, and a, circuit comprising an electric supplysource and a transformer connected to said, supply source and providedwith secondary windingby which currentjs transferred between the main cathode and the anode and between the auxiliary cathode and the anode, the last-mentioned currenthaving a value suin cient' to provide for. ions substantially neutralizing the anode drop of the dischargebetween the main electrodes. I

9. In combination, an electrical discharge,dee

1 vice, for rectifying alternating currents comprising a-sealed gasfllled' envelope, a main cathode, and an auxiliary cathode in said envelope, said auxiliary cathode beingdisposedat a shorter distance from the, anode than the main cathode, and a; circuit, comprising an; electric supply source, means bywhich current is transferredbetween themaincathode and the anode, and a resistance in circuit with the auxiliary cathode and the anode for limitingthe .1current trans-' mitted between the anode andthe, auxiliary cathode to a ,valueat-whicha sufilcientnumber, of positive ions are furnished to substantially neutralize the anode drop of the discharge between the main electrodes. Y

.10.. The om i at n oi, a e c r c di a e device compri ing a gasfilled'enyelopafinanode, an incandescible cathode, and an auxiliary incandescible cathode therein; said auxiliary cathode being disposed in the vicinity of the anode, a

screen 'on the far side 01" the auxiliary cathode I I1. gasfllle'd' incandescible "cathode discharge tube adapted'to be used in, a device for rectifying alternating currents,comprising an env lo e, o'pen ended hollow body ofelectrically 'conduc r ve material therein, a main cathode, anincan iescible' electron eniittingauxiliary, cathode arrai d th g s i holler eh a d an ano 15o placed before the open end of said body and I insulated therefrom.

12. A gasfilled incandescible cathode discharge tube adapted to be used in a device for rectifying alternating currents, comprising an envelope, an open ended hollow body of electrically conduc/ tive material therein, a main cathode, an electron emitting incandescible auxiliary cathode arranged within said hollow metal body, a lead for said body sealed through said envelope, the anode being placed before the open end of this body and insulated therefrom.

GILLES HOLST.

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