US2189619A - Magnetic means for stirring mercury in an ignitron - Google Patents

Description

Feb. 6, 1940. J, SLEElAN ET AL 2,189,619

MAGNETIC MEANS FOR STIRRING MERCURY IN AN IGNITRON Filed July 9, 1938 ATTORNEY APatented Fvebl, 1940 andere PATENT orrica 'MAGNETIC MEANS FOR 'STIRRING l MERCURY IN AN IGNI'IRON l yJoseph slepian, Pittsburgh, and william E. Pakala, Forest Hills, Pa., assignors to Westinghouse- Electric & Manufacturing v Company,

East Pittsburgh, Pa., vania` 4a corporation ofPennsyl- Application July 9, 1938, vSerial No. 218,354

' 7 Claims.

Our invention relates to a vapor electric device and more particularly' to means-for stirring the liquid cathode generally used insuch devices.

In the voperation of vapor. electric discharge 1 5 devices of the type utilizing a liquid pool cathode,

such as a mercury pool, aconsiderable amount of heaty is set free at the cathode spot terminal of 'the electric arc. Due to the lowcoeflcient of thermal conductivity rof mercury, this heat cannot escape readily by v conduction through the mercury lto the cooling surfaces and as a result the surface of the mercury attains a high tem-v for stirringl the mercury cathode vigorously and'v directing it in paths alongy cooling surfaces. Briefly, we submerge magnetic devices in the mercury in such a position that'm'agnetic elds are set up which react with thefelectric currents i in the mercury thus producing motion of the mercury. More particularly, we submerge permanentimagnets, preferably of the horseshoe type, in thev mercury, thus creating a numberk of "strong magnetic fields therein. Moreover, we lrnayrnount guide of some non-conducting material, such as a quartz block, in the mercury just below the tip ofA the make-alive electrode in case suchvr an electrode is used to directthe owof` current which is being conducted by the mercury. When the current which is flowing into theI mercury crosses the 'magnetic fields, a sidewise force is imparted to the: mercury according to well known principles of electromag- .netism and a number of` whirls are established.

By positioning a cooling coil in the mercury In actual.

tions in the temperature gradient along various points of the mercury surface. Y yv Another object of our invention'is'to provide 'means for more effectively cooling .the mercury cathode of a vapor discharge device. j

Othervobjects and advantages of our invention will be apparent from the following detailed description taken in conjunction with the accompanying drawing, inwhich:

Figure 1 vis a sectional elevation of a vapor electric discharge device employing magnets forstirring the mercury cathode showing a v'ieW taken along the lines I-I of Fig. 2,and'

Fig. 2 is a sectional view of the mercury cathode illustrating the location of the magnets "and cooling coils andthe paths assumed by `the mercury when a reaction of the magnetic elduponthe current in' the mercury takes place. j

Referring more particularly'to l, 'illustrate a vapor electric converter 3 comprising an evacuated vcontainer 5, an anode l' and i a cathode. 9 commonly comprising mercury vin the lower portion of the container 5. submerged withinrthe cathode 9 are a plurality of permat nent magnets l l preferably ofthe horseshoe type 'for setting up a number of magnetic fields therein. The magnets H may be either of the permanent type or of the temporary type, such as electromagnets. It is to be understood, however, that while we have shown a specific type of magnet Il, we do not wish to limit ourselves thereby to any one" design or class of magnets vI l. Preferably, the magnets AIl are insulated from the mercury cathode 9 by completelycovering them With some insulating coating y(not shown) such as a vitreous enamel and supporting them by supporting legs I2 secured `to thebase of the I3 or groove inthe yoke lportionml ,to affordja passageway vfor the flow of mercury, aswe shall hereafter describe mo're.fully.y In mounting 'the 'magnets Il in place, we prefer .to arrange the magnets l l so as to have unlike poleslofadjacent magnetic iield.`

In contact with the mercury i slightly projecting below its surface, we have container 5. Each ofthe magnets `Il has a notchy magnets ll together,` thereby being,able` to.`,as-. certain the-,direction of the linesof force of `the Y.

ycathode 9 and K provided a make-alive electrode l'l composed of v In a central portion of the mercury cathode 9 and located below the make-alive electrode I1, we have provided a suitable guide 2l made of some non-conducting material such as a quartz block to direct the now of current conducted by the mercury towards the magnetic fields surrounding the horseshoe magnets ll. The guide 2i may be supported by providing va plurality of supporting legs 22 fastened to the container 5. It is to be understood, however, that the tip of make-alive electrode il need .notbe in contact with the guiding element 2| as suchen arrangement serves no useful purpose.

Referring to Fig. 2, we have provided a'cooling coil 23 which may be mounted radially, spirally or otherwise in the mercury cathode'l. Iii-order' to obtain a more rapid heat transfer from the hottest point in the mercury cathode 9 to the cooling coil 23, we prefer to useza;coilf23 formed of material having a high coe'lcient of heat conductivity such as copper, the exterior surface -of which vmaybe coated `with a suitable nonamalgamable materal'such as -anickel plating. Preferably, we `wishlto locate various portions of thecooling-coil :23. in suchspositions that the mercury, Whenstirred, -will.be inclose proximity to .thecoil 23. The coolingmedium used may be -freshwater and :is admitted into the coil -23 -through .an inlet valve -25 Whichrnay-be used to regulate the flow of water.

.-Inthe'operaticn-.oi' our device 3, a suitable current :is permitted to low. through they make-alive electrode t1 ywhereupon a-cathode spot is produced at the junction of themalre-alive electrode YIl .and the cathode material .9 andunder proper conditions .of-potential, the cathode spot` expands into-an arc, Yufnichimmediately transfers to the .anode 'l and the;rectifying process has begun. In accordance withtheacceptedconvention of cur- ,rent flow, `the rectified -current isconsidered as .owingfrom `theanode 'u'.to the.cathode il and :thence-,through the cathode lead v.21. However, the-guiding element 2 l whichis centrally mounted :in Ithe mercury `cathode ,S directs `the current being conductedbythe .mercury into the magneticiields set up Aby .the magnets Il. In order to.determine the .direction of motion of the mercury, 4the .application ofthe familiar left-hand .rule for motorswhich states that whena conductor.carrying-alcurrent, which in our case is mercury,.is.plaeed.in a magnetic eld,.a ,sidewise thrust is imparted. As a .result Aof `such motor action of the .eld upon the current inthe mercury, ,a .pluralityof whirls 2.8 .are ,established in ,the mercury cathode.andaccordingtc observa- ,.tions in the laboratory Wherefouitmagnets i l are used, eight such .whirls29 were created.

:Although wehaveshown and ,described a cerltain .specic `embodiment -of our invention, `it is .apparent vthat ,changesiand modifications maybe fmade ltherein .without departing vfrom jthe spirit `andnscope ofour invention. We desiratherefore, `that only .such..limitations shall be imposed as arelembodied 1in 'theaccompanying claims or as 'may benecessitated'by the prior art.

vWe claim as curinvention:

l. In'an electrical discharge device comprising a plurality oi principal electrodes at least one of which is a liquid metallic cathode, means disposed in said cathode for setting up a magnetic eld, means for establishing a current in said cathode and means centrally disposed in said cathode for directing ,the current in said cathode into said magnetic eld.

2. In an electrical discharge device comprising ,a liquid metallic cathode, means submerged in said `cathode vfor establishing magnetic elds, guiding means directing the current in said cathode so as to be subjected to the influence of said magnetic fields.

3. An electric discharge device comprising a liquid metallic cathode, a plurality o1 permanent magnets vsubmerged in said cathode, an insulating covering cn each of said magnets, a guide of nonconductingmaterial for directing the current into magnetic fields set up by said magnets whereby a plurality of whirls are set up in said cathode.

Ji. In -an electric discharge device comprising .ev'acuatedcontainen a liquid metal cathode in saidcontainer, an auxiliary electrode in f contact with said-cathode in a central portion therecf `orinitiating valc-athode spot, a plurality of :.permanentfmagnets `submerged. in said cathode,

magnets having their pole pieces in -the -neighoorhoodci said cathode spot, the magnetic elds set up'byfsaid magnets moving portions'of said `liquid cathode ,adjacent said cathode spot s towardslthe .walls of said'container when said cathode is carrying current.

5 An electric discharge device comprising a plurality .of principal electrodes at least one 'of .which is.liquid,an auxiliary electrode in contact f with and centrallydisposed in said liquid, -a plurality-of permanentmagnets submerged in said liquid electrode, means for establishinga current insaidliquid, a non-conducting-guiding element Yicrdirecting thecurrent in said liquid electrode intomagnetic ields set up by said magnets,fsaid rguiding elementcentrally disposed in said liquid .-electrodebut spaced from said auxiliary electrode.

.6. ,In an ,electricdischarge device comprisinga liquid metallic cathode, an auxiliary electrode .havinga tip portion in contact with and centrally .disposed in said cathode, a block of nonconductingmaterial beneath said .tip portion of said .auxiliary electrode but spaced therefrom,

magnetic means forsetting up a plurality ofmagnetic .eldsin `said cathode, said magnetic elds subjectingsaid liquid cathode into a pluralityof whirlingmovements when said liquid cathodeis carrying current and cooling means arranged within said cathode as to be substantially .in parallel with said whirling cathode.

Y?.y Apparatus for stirring mercury in a vapor electric converter comprising in combination .a

plurality .ofpermanent magnets uniformly disposed in said mercury and aguiding element `of A, non-conducting material for influencing thcpath of said mercury when `conducting a currentinto -electrie 'fields set up by said magnets whereby said mercury is subjected to whirling movements.

JOSEPH SLEPIAN. WILLIAM E. PAKALA.

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