US1086418A - Universal electric zinc-furnace with integral condenser. - Google Patents

Description

J. UNIVERSAL ELECTRIC ZINC FURNACE WITH INTEGRAL CONDENSER.

THOMSON.

APPLICATION FILED MAY 8, 1913,

Patented Feb. 10, 1914.

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WIT #58858 J. THOMSON. UNIVERSAL ELECTRIC ZINC FURNACE WITH INTEGRAL CONDENSER.

APPLIOATION FILED MAY 8, 1913. 1,086, 11 8. r Patented Feb, 10, 1914.

4 SHEETS-SHEET 2.

Q ATTZNEp O J. THOMSON. UNIVERSAL ELECTRIC ZINC FURNACE WITH INTEGRAL CONDENSER. APPLICATION TILED mm, 1913 1 86, 11 8, Patented Feb. 10, 1914.

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A T TURN Y J. THOMSON. UNIVERSAL ELECTRIC ZINC FURNACE WITH INTEGRAL CONDENSER.

APPLICATION FILED MAYB, 1913.

Patented Feb. 10, 1914.

4 SHEETS-SHEET 4.

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"nitrite STATES JOHN THOMS'QN, "'JF NE'W YORK, N. Y.

UNJTVEE SAL ELECTRIC ZINC-FURNACE "WITH INTEGRAL CONDENSER.

Specification of Letters Fate-n2.

Patented Fob.1(),191fi.

Application filed May 8, 1913. Serial No. 766,248.

3? '2 all 10710977 'i may (Wu-001m J 01m THOMSON, av citi- Be it known than. I zen of the United Sir-tee, and u resulent 0t the borou 'h o't Irianhatt n of the eityof New rk, Stu of New Kerk, have invented certain new and metal Improvements in U in. i own 'rnuees with. Inte grill C... no ioilowing :1

soeeific 5 to the no eompeuvin drawing, fuming; a part, liereot. he invention relate. to the metallurgy 1g. 2 is a partial side elevation; Fig. 3 is a vertieul longitudinal section, viewed as denoted by eitlier of the arrows B :21 B down to the liOl'lZOiliill plane I") And tl'senee ii central =tion inhen us on the pi' e denoted by the Zines vie-exert in either enteit in, the arrows in Big. {of plan view n the iett hu iier line ii, whiie r right hmni portion is horizontal seetiou along I we plane Y); Fizz. 5 is u. lmrizoritui seeiion, the luff inuul hull of whiii is along the plane E illlfi the other or i lurml Milt being alone the plane i 'ilii :in'iniee is particularly iutezuleil tor the 3 (auction oi. igneou, oxiei. ut zine romhined with (Jill'ihlllli when the inert when. of the re ct-ion is of ,sdiilli amount and. oi nu iishy or y eharueier, uinl for any euitiri riiriized zine or lend-zine ores having u considerable content of gnngue oi eueh character as eupabie of being tluiiiizei h To avoid explanatory statements e rich would in feet be in the nature of repetitions it is stated that this application is .roore or lees; ee rel rt ad with several pending appiie: tions 1i hy the present applicant on Januarv 2115; 195%; and zippiieaiion bearing iii-sh we filed on said date, is porti ulerly cited. Tl11S 2\PPi1OEliL1OI1 is alsoyrelgrtezi to my application bearing Serial No.

iii-n1, 19w.

The decomposition of the charge is (atteoted by heatderiveal by direct eonliluetion or radiation or h boili, preferably from electrically incited compound porous lied-resisters. such us urcordinarily termed from pieces of broken carbon interpolated be tween terminals.

The resistors, as ii, are laid parallel to each other, separated by a space i in wliieh severni transverse thrust-plates L'U'ilifi disl 5! 4 i l w v pewu. iii rtlnuso-phites ale pleierubl of a i ziierul whieli is zi noi'i-eonchietor of elwtrieity. When the resistors are o' 'unrgiteit in series, as is here shown, one pair of -L sister-ends in eouiiuet" with carbon terminah; (i, 7, while. the opposite ends contort with the (EOHRQCi'Ol 8, which is situated With in the furnace Walls. This: connector S eleetri "ally Connects the resistors, prejti lx' in series, and nury', like the tei' ninnl sflie formed of a series of carbon bleeles stocked one upon another, as denoted. in Fig. 3.

Beneath each resistor is :10 sump 9, 9*, aeross whim a series of spaced bars or 1 g l, are 12, are lniel and u on whieh ihe re or zirhon suppmteci. 'liese rods crmstltute n iiQiili'il z ncl may riesired form of I pert ions may he uti ized. iiet'reeu the loi the out ltililli furnace wells 1-23,

by means: t transverse slabs, :1; 14, preterahly into the furnace walk, us :it 15-, suh-(liriue the gaps into pockets, us 16. The tops of the esistors us also ine intervening were I are er ere i by i rielis or tiles, us l The elm uniternri l; is pieced in the soul i should also more or less till the ()hviously, the "em-lion muse Luke piuee (along or in front '1 the oute' vertieui Faces of the is o \(Iliitllilttl prmluvts mess up;

t thereof riggi and leti in her zuntzil planes from the reneiwn zones, .i ig. I1. through theiustiues of the carbon reistor and into ihe central space The action and renetionot the heat emitted from the inner vertical faces ()filiS resistors is direct, substantially equal and opposite, indieoted bv the '.11-- rows 03; thus filler-e is e omparutr 31y little less of lien 'ei'iergy from the resistor-s. The

funie and gas after ieevin the resistors (ler 31y, aSfarr W e,

sparing Serial Nos. 760,915 and 760,916, tiled A- iril the adva ntagcs derived from the use of such a through a slot or throat 18, or a series of ports, into an underlying longitudinal space or expanding cl lamber M. In other words, essentially all of the heat carried to or into the said chamber will only be that neces sarily stored in the flowing volatile matter whose temperature will be equal, or approximately so, to that of the resistors.

If the material under reaction is ofacharenter to produce a modicum of ashy or sintery residue, such as usually results-when igneous oxid of zinc (ZnO) and carbon in the form of coke (C). are brought together or commingled, as for instance, igneous oxid of zinc and coke, both of commercial purity, such ashy or sintery residue may be intermittently withdrawn from the bottoms of the pockets through the openings or ports N formed in the side walls of the furnace, or it may thus be partially or wholly poked forward through the grate-bar spaces, whereby it may fall into the sumps. Contrariwise, ii the charge material is combined with gangue capable of being dissolved to a liquid slag, this will run forward along the slopes S and thence through the aforesaid grate-bar spaces down into the sumps, as indicated by the arrows i. Such may also be the case if lead is an element of the charge and is lib- .e ted as liquid metal. In certain cases slags fi dihzinkiferous ores, or concentrates thereof, cannot be readily reduced to such .a degree of fluidization as will. run freely. Consequently small tap-holes are liable to freeze even after an opening has been effected. The opening of the small tap-holes is often quite difficult and this objection has been obviated by leaving all or a considerable portion of the outlet end or ends of the sump open and forming an outer recessed portion against whose abutment, as 19, Figs. 3 and 4, in initial closure is effected by means of a thin refractory plate, as 20, upon whose inner 'face a layer of suitable lire-clay paste, as 21,

has been applied. Once the sump is emptied, such a plate may be easily and quickly thrust into cont-act with the abutment at which the fluid-seal is made. "The plate is then held securely to its position, and any serious emission of heat is also thereby avoided by inserting a large free block, as 22, supported and additionally sealed as by a packing of granular carbon or sand 23. lVhen the sump is to be emptied the aforesaid free block is removed, the thin inner plate or seal is smashed inwardly and the slag is thus almost instantly liberated free to flow out in large volume, if in a fluid state or to bescrapcd out if in a past-y condition. While a new plate requires to be furnished after each tapping, thc'cost thereof is negligible and of little consequence when compared to construction. In this context it may be best to here point out that the connector 8 which would ordinarily be artificial graphite of high heat conductivity, is preferably supported across the sumps by a relatively thin refractory, as 24, Fig. 3, set immediately above and contiguous to the tap openings. Yet the said refractory 24 may be dispensed with, but there would then be some risk of burning due to the entrance of a em all amount of air when the ends of the sumps are open. To prevent or minimize this burning which is liable to take place, the slag or other liquid matter is maintained hot-close up to the sealing plate. The connector is preferably set upon a layer of unbound granular material, such as carbon or carborundum, and is also backed with a layer, as 25, of the same character. In this wise, by removing the top layers of bricks, the backing may be packed down or be more or less removed at one end or the other of the connector, whereby to equalize the intimacy of contact, thrust or pressure upon the resistors and to balance the thermal effects .thercin by increasing or decreasing their relative electrical resistances.

The horizontal zone of the furnace bcneath the plane indicated by the arrows 13 or F, constitutes the condenser, and it is preferably comprised in a series of lateral chambers P formed by the septums 26 which also serve supports for the superimposed structure. These chambers may be filled. with broken filter carbon, as 27, or with spaced or laminated diiiusing plates, as 28, or with any arrangement of staggered rods or plates, such as 28 29, Fig.5, or with any combination thereof, as may be desired. The outer ends of these chambers may be left open, or they may be inclosed, as ill), Fig. 1, having a slot, or tube as ill, for the escape of residual gases, or outer sheet metal casings, as 31, may be employed, open at the top, as 32, from whence CO passes to atmosphere. The bottoms of the chambers l. are preferably formed of tampcd material 33,i1npervious to molten metal, sloped dmvnwardly each way from the longitudinal center of the furnace and connecting with suitable spouts, as 3 1, 3%, tor conducting olf liquid zinc.

It will now be perceived that the hot fume and gas will be ejected from the throat 18 at relatively high velocity, expanding and filling the chamber M, thence deflecting and flowing right and-left through the condensing chambers, as indicated by arrows in, m. During this transit, if the chambers are filled with broken carbon or the spaces between the plates or rods-are vertical, the lighter gas, as denoted by arrow n, Fig 1, will rise, the denser fume, as denoted by arrow 7', will fall and the condensed zinc will precipitate upon the sloped bottom or sole and thence flow down to and out at the spouts.

The diminution in temperature between the' fume and gas in the space between the resistors and that in the expanding chamber will, at a normal maximum rate of reaction, be but trifling, and as the slag-sumps are above and contiguous thereto the heat loss from the sumps, by conduction downwardly, isthus sfo nearly completely compensated as to be merel nominal; therefore the drain of energy rom the lower portions of the resistors becomes negligble.

In constructing the furnace it is prefer able that at least one or two .courses of the bricks'beneat-h the tamped bottoms of the condensing chambers, as 35, and at the extreme ends, as 36, Figs. 1, 2 and 3, should be of the best quality of non-heatconductive material. Now, assuming an adequate realization of the several foregoing features, it necessarily follows that essentially all of the heat units of the fume and gas which is conveyed to the expanding chamber can only be dissipated in horizontal directions, and that as the drop in temperature between the longitudinal center of the furnace and the outer ends of the condensing chambers may be of any difference desired, or as between that of'the inner hot gases and the outside atmosphere, it will be apparent that the ideal conditions essential for complete and effective condensation of zinc fume to liquid metal are realized. Or to otherwise express it, the temperature drop will progress in uniform increments from the entrance to the exits of the condensing chambers, the

ultimate discharge of temperature and calories being ractically solely from the muzzles thereof. Consequently, as the filter carbon or the plates, or the rods within the condensing chambers, as the case may he, cannot transmit heat in sensible amount at right angles to the direction of the flowing fume and gas, but solely in the direction of their flow, it simply becomes necessary to control the rapidity of heat radiation from the outer ends of said chambers, that is, relative to the volume of hot fume and gas delivered into the' expanding chamber. To realize this condition, as has already been pointed .out,-.the ends of the condensing chambers may be left open to atmosphere, or they may be inclosed by heads more or less thick andof material more or less heatconductive. Moredver, if the evolution of fume is at so low a rate as not to require the.

entire condensing capacity of all the chambers, then one or several of them may be completely sealed, that is, out out; or if the rate of evolution is beyond the capacity of allthe condensing chambers, even when delivering their residual gass direct to atmosphere, the metal shields 31 may be employed whereby any impinging fume, as arrow u, would be chilled and regained as blue powder.

The'unique accessibility of the principal tcotirdinating elements of this design is a teaturewh ch 1n an industrial sense 15 second or with equal facility be removed, while spaced plates are used they can inspected, cleaned or substituted by others .as'needw be.

No overall cover shown in the drawings in that ordinarily none is required, for charge materials such as Zntil-l-C or concentrates make, on the one hand, an e" lent air seal, while on the other hand i pro-heating acquired from the tops of tilt resistors serves to vaporixe entrained moisture and to expand entrained air, both of which escape to atn'iosphere. But it the charge materials have been SOPzll'itl'Uljf pro heatr'l, as in a fuel-tired furnace, then a cover may be advantageously cmph'iyed. So too in the primary starting of a ii'urnzu-c cover should be added to prevent the .arc sistors from air-burning. When such a cover is in place inert gas may be introduced into the furnace. This gas by its pa sage through the re istors may become heated and finally Hows down and thrc the condensing clunnbcrs until a proper t-ial temperature is realized therein. The charge is then introduced alon the faces of the resistors and the reaction instituted.

The condensed zinc may be drawn olt' con-A tinuously, or when the outer ends of the condensing chambers are inclosed the spout openings, as Fig. 1, may be scal-cd, whereby the liquid metal will back up to be intermittently drawn oil.

Referring particularly to Fig. 1, it is to be observed that a single resistor may be readily substituted, if such should be deemed preferable, for the two that have been described. A ready means of making such a substitutionmay be to use longer grate bars, whereby to span the throat, but the thrust plates w would then be removed. The prim cipal difference resulting from such an arrangement is to considerably diu'iinish the electrical resistance over that of the two resistors, that is when such are operated in series.

The septums 26 need not extend entirely to the outside surfaces of the furnace walls, in which instance an outer connecting space would be formed analogous to that of the central expansion chamber. P69" contra, the condensing plates, as 28, Fig. 5, may project beyond the outer faces of the furnace into atmosphere, thereby considerably increasing plates, but the sumps, said resistors being connected their capacity to conduct and dissipate heat. 1

The longitudinal expansion chamber M may itself be more or les illed with carbon or rcstrir ion of the filtering or diffusing material to the condensing cham bcr spaces appears to be the more advantageous. Again, instead of having a distinct spout from each chamber,- a zinc receptacle may be formed in the bottom to pass through the furnace longitudinally, thereby collecting the liquid metal from all, or tro'm each right and left hand seriesof the chambers and delivering it at a single spout.

The mention of the foregoing modifications is regarded as a. sutiicient attestation that various others may be made by those skilled in the art Without departing from the fui'idamental features of this invention.

What I claim is:

1. In an electric zinc furnace, porous carbon resistors, parallel charging gaps or pockets, ports in the furnace side Walls,gratings upon which the resistors are sustained and suinps beneath the gratings, said ports being ar'anged so that an ashy or sintery residue is removable therethrough, and the gratings being arran ed so that fluidized metal and slag fiow into the sumps.

2. An electric zinc furnace having parallel carbon resistors electrically connected in series within the furnace by a carbon connector having a space at the rear thereof filled with free or unbound granulated re-' tractory matter.

In an electric zinc furnace having parallel carbon resistors and underlying Within the furnace so as to be electrified in series by a carbon connector which is :irranged to span one or both of the underlying sump 0r sunips at or contiguous to the sump tapopcnings.

Ti- An electric furnace having carbon re sisters for operating in series, an electrical connector therefor and. sumps below the re sisters, the connector being located above and spanning the sumps.

5. In an electric furnace, a longitudinally extending sump having an open tap-end inclosablc by a separate retractory plate thrust against an abutment by an outer block.

6. In an electric furnace, a sumpwhose tapping opening is closed by an upright refractory plate which is broken when the contents of the sump are to be Withdrawn.

7, An electric zinc furnace having adj-2 cut to the lower portion of the carbon resistor a sump for receiving fluidized metal and slag, said sump having its tap opening closed 'by aseparate plate Which is broken when the sump contents are to be Withdrawn.

An electric zinc furnace comprising charging gaps or pockets, porous carbon reistors or a resistor, from. whence the veintilized products of the reaction are and a plurality of underlying coudensi g chambers, the furnace being provided with a gap or throat through which the fume and gases pass from the resistors to the chainhers.

9. In an electric zinc furnace, paral. porous carbon resistors which h I. 1 space between-them, charge-recci ng pooleets arranged along the outside vertical taces of the resistors, and a condensing system in the base of the furnace, the furnace comprisdcri ved,

ing a portion having a, slot, throat, port or ports through which the fumes lion in passing from the space between the resistors to a the interior of the condone g chambers 10. In an electric Zinc furnace, a piur of transversely disposed coudensin cl... bcrs located in the base 0' anmverhead portion pro it n t-udinal slot, throat or series oi? ports which connect the chambers to a superimposed. source of supply of .tume and. gas.

11. In an electric zinc :turnacc,

upon which a carbon resistor is su and beneath and contiguous to Whicrl is the hot Zone of a condensing system. 12. An electric zinc furnace having spaced parallel resistors and a, condcnsi L comprising aiplurality of chan bireceive from the space between tl i'tl the hot volatilized, products of the. reac at their inner ends and which it residual gases at their outer an phere.

11-3. in an"electric zinc 1t ing system comprising a pluraiih of horizontal chambers having therein filter mean. bcrs, said chambers being so arranged and disposed that the filter members may moved or replaced from aloi'ig the outer walls of the furnace. I

14. In an electric zinc :t'urnace, (lensing system co'inynxising a plurality of chambers more or a St} nip a ccndcnaless titled with filter members"- betwcen which the luaic' ann laterally but are free to separate v ,rtically according to their respective densities.

15. In an electric zinc furnace, two series of transversely disposed condo sing chain'- bers having a central longitudinal e; vanding chamber into Which the volatiiized products of the reaction are delivered tieally and from whence all of the s d condensing chambersare supplied horizontally.

This specification signed and witnessed this at day of May, 1913.

JOHN THOMSON. Signed in the presence o1 V J. R. OMERA, F. A. KUBLER.

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