US1090427A - Electric zinc-furnace with integral condenser. - Google Patents

Description

J. THOMSON. ELECTRIC ZINC FURNACE WITH INTEGRAL CONDENSER.

APPLICATION FILED JAh'. 2, 1913 Patented Mar. 17, 1914.

4 SHEETS-SHEET 1.

Mfwessss:

I J. THOMSON.

ELECTRIC ZING FUBNAOB WITH INTEGRAL CONDENSER.

APPLICATION- FILED JAN. 2, 191a.

Patented Mar. L7, 1914 4 SEBETBSHEBT 2.

J. THOMSON. ELECTRIC ZINC EURNACE WITH INTEGRAL CONDENSER. APPLICATION- FILED JAN. 2, 1913.

1,090,427. Patented Mar. 17, 1914. I 4. smarts-sum a.

Wifnesses J. THOMSON.

ELECTRIC mm summon WITH INTEGRAL cormmsna, IAPPLIGATIOH YILED JAE-Y. 2, 1918. LGQQ LLQ'Y. Patented Mar. 1'2, 191 1 4 sums-sum 4.

COO/CO k g M'fnesses: E

QfK/QWAE designed to accomplish the objects above i 0 current, which is brought to the two ends of a complete reduction and evolutionin the To all whom it may concern the zinc to liquid metal as and when and at the latter being placed directly upon and JOHN THOMSON, OF NEW YORK, N. Y.

ELECTRIC ZINC-FURNACE WITH INTEGRAL CONDENSER.

Specification of Letters Patent. I Patented 1131', 17, 19f| .1

Application filed January 2, 1913. Serial No. 739,787.

Be it known that I, JOHN THOMSON, a citizen of the United States, and a resident of the borough of Manhattan of the city of New-York, in the county and State of New York, have invented certain new and useful Improvements in Electric Zinc-Furnaces with Integral Condensers,. of which the following is a specification, reference being made to the accompanying drawings, forming a part hereof.

This invention relates to the metallurgy of zinc and the object thereof is to produce metallic zinc by the reduction-of oxid of zinc (ZnO) by carbon (C) also tocondense the rate it is produced. The heat necessary for decomposing the ZnO and C is derived from an electric current passed through a resistor.

The invention resides in particular *means stated in a practicable and effective manner and upon an economical commercial scale of operation. i a

The resistorabove mentioned is comprised in a bed of carbon, usually made of coke, which is disposed upon an open refractory grating, formed of bars or plates. The size and shape of the carbon pieces as well as the depth, width and length of the resistor bedw may be variously modified to obtain any desired electrical resistance and intensityof the resistor by blocks or-plates of amorphouscarbon or graphite, situated at and within the ends of the reaction chamber,that is, theresistor is interpolated between the two terminals. r

'The reaction chamber of the furnace in which the resistor is contained is made of sufficient depth to receive a shallow charge,

sustained by the resistor. The charge 15 comprised-of either a mixture or alternate layers of oxid of-zinc and of carbon in preferably the exact'relative proportions to effect, when suitably heated,' practically their forms of zincrfume (Zn) and monoxid of carbon (C0); thatisto say, any unevolvablc or inert residual matter will be of nominal or ev e n negligible amount.

As already intimated, the electric energy l is transformed into caloric energy in the resistor bed, and the heatthus enerated, if the temperature is adequate, e ects the decomposition ofthe superimposed mass, the

following representative chemical ensuing ZnO-l-C Zn-l-CO.

In general terms that portion'of the base reaction of the furnace immediately beneath the resistor is utilized to condense the zinc fume, to collect the liquid metal and to evacuate the residual gases. In other words, the underlying section. contiguous to the reaction chamber is caused to serve-asthe con denser. Means are afforded. for obtaining and maintaining adequate intimacy of corn tact between the resistor and the charge, whereby to producea uniform absorption of heat units and a correspondingly effective evolution of volatilized products. The manner of making electrical contact between the carbon terminals and the resistor and the method of connecting the. said terminals to the bus-bars or main 'line'cables are mattersv of importance; these details have been improved. When .oxid of zincof a low grade of commercial rarity-and carbon in the usual form ofco' e or 'coalare employed, it

has'been found desirable to so dispose-and sup ort the bed resistor as-to increase the period of its effective endurance and. to also facilitate its speedy substitutionwhen renace, .byreduction of heat losses due to radiation, is improved and finally a design is provided whereby the reaction may be caused to proceed at or about or even slightly below atmospheric pressure.

When the ZnO-l-C reaction is employed to primarily produce zinc fume from its oxid the resulting classical formula,

ZnO-l-C Zn-l-CO,

'quired. The thermal efficiency of the furmercial oxid of zinc and if it has not been calcined and compressed. These materials emplified by the classical-formula. It is.

also well established that zinc metal when fused will remain liquid up to or about the temperature of 17 10 F b'ut'it then, if supported with the latent heat of volatilization,

becomes a'elou d-like or gaseous fume, that is, if boiled in the atmosphere and hence visually observable. This is also the basis usually accepted as applicable to zinc-fume when produced by a chemical reaction.

. When zinc-fume is evolved the pernicious oxidizing element CO may also be present, the effect of which'would ordinarily be to precipitate a portion of the fume, in the form of blueowder 'oras schmelz or in some com ination-of both. But if the CO mingles with'the zinc-fumeand CO in the presence of carbon (C) and all are subjected to an adequately high reacting temperature,

then there will be a secondary, reciprocal or interreaetion which virtually acts to cleanse" such portion of the zinc-fume as may have been oxidized'by the CO Ordinarilythe quantity of ()0 will be relatively small and as its density is also greater than thatof'CO it is highly diluted. As an oxidizing agent both time and temperature are doubtless functions-of the action.

Having regard thento the foregoing general outlines and to these expressions of the controlling principles, the severalcoiirdinat- -ing features of the invention will now be described in detail, reference being bad to the illustrated example or embodiment thereof shown in the accompanying drawings in which- Figure 1 is a transverse center section, viewed as A, of Figs-2, of afurnace denoting a realization of the invention the resistor having been removed from the right half of the furnace. Fig. 2 is a longitudinal center.

section, viewed as B or B of Fig. 1. Fig. 3 is a transverse center section, viewed as C, of Fig. 4, indicating a realization of the invention in another form of apparatus, the resistor being indicated by the-dotted line. Fig. 4 is: a longitudinal-center section, viewed as D or D of Fig. 3. Fig. 5 is a partial horizontal section and plan, viewed as E, of Fig. 3. Fig. 6 is a detached, enlarged bottom endview of a terminal; and Fig. 7 indicates upon a large scale certain constructions of the condenser members or plates which may be employed and which cannot be conveniently or clearly denoted in the main figures.

R is the reaction chamber; S the resistor; V the carbon terminals; W the charge in reaction; T the reserve or'overhead charge; Y the hearth, and X is the zinc collector or reservoir. a

The grate which forms the resistor hearth, as in Figs. 1 and 2, is formed by a series of spaced refractory bars- 8, while in Figs. 3 and 4 plates are employed whose upper portlons serve as grate members. These bars or plates are preferably formed with sloped edges 9, and the intervening spaces-10 may also be wider at their bottoms than their tops, which will facilitate-the flow and clearance of inert residual matter or particle s of carbon. The width of the grate spaces is to be such that normally the pieces of resistor carbon will bridge them, but in any case poking from above, to pass'through and collect below, as in the chamber H. This also the temperature of the. resistor be temporarily considerably increased above the normal, whereby a viscous or semi-1i aid or even a liquid slag will be produce But whetherthe slag is in the form of a sinter or liquefied, it'may be tappedofl or scrape'd longer period of time than if the inert residue is collected upon a solid hearth. In fact, the operation may continue more or less indefinitely. If necessary the resistor and gratebars may readil be removed. To effect thisandto avoi an extreme reduczone or a'portion of it, as L, is made removable. WVith this off, asthe reaction chamber is relatively shallow, the resistor carbon, grate bars and also any residue may be rapidly removed, as by means of forks, tongs and shovels, even when quite hot 50 too the heated grate can be quickly .replaced into'position. The grate spaces also .perform another v function which will again'be referred to. Thisreniovable zone Lis readily formed by the employment of built up refractory jblocks held' under right. angle formation of a series-of transverse slots 15 through which the reserve charge may be fed into the reaction chamber. As shown in a series of roundf-refractory rods 16 which l also serxe as thrust pieces or "compression permits, if desired, thatdissolv ent material such as lime may be fed in at intervals and and a fresh bed of resistor carbon be; put

Figs- 1 and 2, the slots are obtained by using .they will serve to permit the fine ash orv sintery residue, either by gravitation or out, as through the closable opening12. In this wise the resistor maybe operated for a tion of the furnace temperature, its upper tension, as by means of steel channels 13 and' rods 14. It also lends itself readily to the members. These maybe so placed, relative to each other, as to produce openings of any desired width. Thus the material may run through freely, the slots themselves may be closed by supplemental round rods, as 17, or they may be so narrow that the super-charge must be forced through by bars. In the latter instance the material will itself form a seal, as in the instance of a sand-joint. The feeding-bars may be utilized to spread the reaction charge and to tamp it down into intimate contact with the resistor; The temperature of the charge and the resistor may be ascertained through these slots and any collection of water vapor'or CO in the space above the reaction charge can readily be permitted to escape, as through a pipe or by perforating the reserve charge material at any of the said slots.

Figs. 3 and 4 show a modified form in which the round-rod construction is shown as substituted by molded sections 18 and the dotted outline 18* shows how a longitudinal may be introduced or substituted if desired.

While the reserve charge T may be maintained in a relatively deep open shaft, it is ends of the reaction chamber.

regarded advantageous not to load the resistor with an'excessive supply of reacting material. The principal reasons for this are that less electric current will pass through athin than a thick charge, consequently there will be less tendency to reduce the current density and temperature in the upper surface of the resistor. Also with a deep reaction charge there is a greater mass ofmaterial at some distance above the resistor, in which the temperature is not high enough to produce Zn and CO.

The carbon terminals V, instead of being builtinto thewalls of the furnace horizontally, are inserted vertically into the open Relatively thin plates may thus be used and they can be readily withdrawn and replaced if desirable, concurrent with the, substitution of a. fresh resistor for an old one. The lower ends of the terminals may either rest upon some portion of the furnace, as 19, Figs. 2 and'4, or they may be embedded in and rest upon the resistor carbon. To obtain an increased area pf contact between the terminals and the resistor a plurality of wedgelike grooves or slots 20, as shown for instance in Fig. 6, are formed in their lower faces. The resistor carbon is packed into these grooves, as shown in Fig. 2, with the result that the area of surface contact can readily be increased over that of a simple face-cont-actby from 35% to 50%. The current' from the bus-bars or main line cables 21 is conducted to the upper ends of the terminals by means of metallic electrodes such as copper, preferably in the form of thin wide sheets 22, their inner edges being bent to a right angle flange 23, entering a recess 24, milled along the upper ends of the said terminals. Where these electrodes pass out over the walls of the furnace they, as also the upper exposed ends of the terminals, are covered by brickwork. The inner faces of the terminals, those presented toward the reaction chamber, are also sheathed by suitable removable refractory blocks or bricks 25 whereby there can be no electrical contact and no reaction set up with the ZnO of the charge. Apart from the advantage already mentioned, this disposal and construction efi'ects a practically ideal transmission of the main line power factor directly at and into the resistor bed, which is a feature of prime importance when considering the somewhat complex conditions under which the furnace must be operated.

The power circuit is denoted by P, Fig. 2.

In the present scheme of condensation all of the volatilized products are caused to pass from the reaction zone directly and immediately through the resistor in a vertical direction downwardly into ducts, slots, slits or spaces whose boundary surfaces progressively diminish in temperature away from the resistor.

In the operation of this furnace and its integral condenser the temperature at or near to theimpingement of the charge upon the resistor, as in the resistor itself, is preferably maintained sutliciently high to prevent the existence of CO Moreover, as the chemically evolved volatilized products of the ZnO+C reaction pass directly and immediately into and through the highly incandescent carbon of the resistor, pernicious re-oxidizing mediums will be eliminated.

One manner of realizing the condenser system is shown in Figs. 1 and 2 and another in Figs. 3 and 4; Either manner may be said to be a detail modification of the other, but each will be somewhat separately described. Thus in Figs. 1 and 2 thechamber H beneath the grate bars is formed by a series of horizontal ship-joint plates 26, supported by ledges 27, formed in the tamped lining 28, which forms the reaction-and condenser chambers. The grate bars are shown' as sustained on these plates, as by means of strips 29. At one end of this chamber 'an opening 30 is provided and the plate contiguous thereto may have a raised retaining lip or rib 31. Beneath these horizontal plates are a series of vertically disposed plates, as 32, 33, supported by ledges 34 in the tamped lining. One series of plates 32 are in contact with the horizontal plates above, and the other series 33 alternating, leave a space as n above and project downwardly into the zinc receptacle, whereby the spaces are connectedin series. In preliminarily starting the furnace a sufficient quantity of molten zinc is to be introduced until the lower edges of the plates 33 are immersed therein. As a consequence the lower, boundaries of the spaces or galleries are formed of molten zinc. Now, what will occur is this: The zinc fume and monoxid of carbon as theydeave the resistor will pass throughthe grate bar spaces 10 into .the chamber H and thence through the opening 30 and down upon the zinc bath. Continuing, asindicated by the arrows, the zinc fume and gas must thereafteralternately rise and fall, impinging upon the bath at each downward movement, with the complete circuit equal to the length of the chamber is reached, from I whence anyresidual gaseous products flow out of. the condenser chamber right and left, asby the parts 35, Referring now to Figs; 3 and 4: Here the "function of the grate bars is performed by plates form horizontal chambers K, the bot- -toms of which'are zinc, part of which are connected at one end to the walls at one sideof the chamber and the rest of which are connected at one-end to the wall at the other side of the chamber, as in Figs. 3

and.5. Now, what will here take place is this: Thevolatilized matter and also any residual ash produced by the reaction will fpass from the resistor immediately into the .spaces 39, between the plates; and thence to the'chamber H. .Here the ash or sinter will remain, to be withdrawn as desired through the opening 4(),'but any condensed zinc, zinc fume and gas pass on through the endport.

30, down upon the liquid bath of theprimary chamber, winding back and forth horizontally through the tortuous course, in

constant contact with the bath and the sur-.

faces of the plates, .the residual gas finally leaving the condenser chamber through the ports 41, 42. The residual gas is received from the zinc receptacle ports by side chambers J, Figs-1 and 3, which extend along and in fact blanket bot-h longitudinal sides of the reaction and condensing chambers, from whence it ultimately passes, as

43, to mingle with the atmosphere as such or to be burned to 0.0,. These side chambers perform a two-fold function, to serve if needs be asrollcting chambers for blue owder which may be scraped out th ough openings, as 44, and as the temperature of the gas .will be relatively high. its presence "in these blanketing chambers minimizes emission of heat sidewise from the hot zons fuel heat, as the need may be,

of the furnace. In this connection the axiom should also be borne in mind that wherever the greatest difference of temperature exists,- as between a hot and a colder body, the rate of energy flow will there be a maximum, also that the cross sectional form of a heat emitting member (resistor) is amatter of prime importance. Thus to illustrate, a metallic rod-resistor of one inch diameter, having a section of .7854 square I inch, would have a heat emitting surface of 3.1416 inches, whereas the same section in the form of a strip .05 inch thick would.

have a heat emitting surface of 31.5 inches. In this furnace, as is indicated in the fifilwings, the resistor is relatively thin to its width and in practice may have a relation of from about one to five, to'six, or seven;

consequently only about 10 to 20%0f its surface is in contact with the sidewalls of the reaction chamber, and to 85% of the surface must emit its heat above to the charge and below to the sustaining grate and the interposed spaces. It then necessarily follows that if the temperature of the volatilized products contiguous to the lower surface of the rcsistdr is high, andif'the heat insulation at the sides of the resistor is good, the bulk of the energy developed in the resistor will flow where it is desired, to the relatively colder charge above. In the described traverse of the fume and gas, a

considerable portion of the fume may be condensed in the vertical grate plate spaces,

and by impingement upon the horizontal plates 26 which, if desired, maybe slightly horizontal'septum' formed by the plates 26 sloped toward the port or opening 30. Themay preferably be-of say fine clay havinga less capacity for heat conduction. Consequently if, to illustrate, the temperature at the impingement of the resistornpon" the grate is- 240091 then the temperature in chamber H Fig. 4, may be about 15093 to 1600 F., while that of"the septum ltself would be still lower. It..is. to beobserved that the fume and gas. will considerably expand as they leave the grate spaces and enter the chamber H. Beneath the septum,,

between it and the zinc bath, a further fall of temperature is contemplated, sayto about 1200 to 1300 R, which is controllable, according to the rate of delivery of fume and gas, either by circulating air or through the fines or a flue, as U. situated beneath the zinc receptacle.

forming the said receptacle supported upon a steel plate '0, whereby a rapid interchange of heat may take place, as between the bath and the flue. The control of tem- The tamped material perat-ure in the bath is a matter of importance. Where ideal conditions exist this maybe automatic, as by natural conduction.

But the higher its temperature, or in other .words, the less difference of temperature between the bath and the resistor compatible with condensation, the greater will be the flow of heat to the charge. l

, The phenomenon has long. been known that, as usually stated,-'zinc fume condenses most efi'ectivelywhen in the presence of liquid zinc. Substantially the same condensing .efiects will ensue if thezfume is caused to flow over surfaces, between slits, across obstructions and also if rapidly and frequently changed in the direction of its flow, espetions become clally where impulsive impingements or centrifugal effects can be'realized. Such condithe more necessary as the volame 'of fume relative to that of the gas is diminished.

The' above conditions are realized in the circuit through which the fumeand gas arecaused to traverse between the septum and the bath of molten zinc. Thus, referring to Figs. 2, 4 and 5, in the furnace of ordinary capacity it is entirely feasible -to obtain hunforty to sixty lineal feet hundreds of square feet of plate surface conorepver, any or all ofthe ate bars andplates' may be pifoyided with sharp ratchet-like recesses, asf;17, Fig. 7, or with projecting ribs, as48, and if these are op- 1 intersections with the main (5 pos'edinstaggeredrelation, as shown, the flow-area need not be reduced while a vast number of tumblings, mixings and refractions of the fume would necessarily ensue. These ribs or recesses may either be disposed obliquely or at a right angle to the flow. Such platesmayeasily be formed as bya molding or extruding .process,and if the ribs orrecesseshave sharp right angle body of the plate, as 49, they will serve as j pockets, .collecting small quantities of 'zinc against which the fume must impinge whatever may be the of the plates 36 are to direction of flow.

As the li uid zinc accumulates it may be intermittent y tapped off, as at 50, Fig. 2, or a siphoned outlet 51, Fig. .4, may be employed whereby theoutfiow would be continuous and the head be maintained at a uniform level, as indicated. The spaces beneath the bottom edges of the plates 33 and the openings 52 formed b the legs v3'? be sufliizient so that by emptying the zinc chamber it may be scraped clean should such be necessary, as through the large openings 53 provided for that purpose. If the conditions are such, however they may be produced, as to sensibly obstruct the flow of the fume and gas, this will cause back pressure at and in the 'on in an open crucible reaction zone. The ZnO-f-C reaction proceeds most effectively at or perhaps somewhat below atmospheric pressure. lvloreover, when the reaction takes place under such. pressure as it may proceed at, it has the contingent objectionable effect of forcing the zinc fume into the refractories. These difiiculties may beover'eome or minimized by the simple expedient of prox'iding-at or near to the tail end of the condensing circuit, means for producing suction, whereby obstructions to the flow such-as friction-head may be partially or wholly nullified, or even negative pressure may be maintained. at the reaction zone. Suction may be positively effected, as by the use of a vacuum pump or fan connected as at 54, Fig. 1, but as the actual friction head here to be dealt with .is relatively trifling, such can be overcome by means of tubes or,a tube 55 connected to the side chambers and by sufficiently extending it upwardly the effect will be similar to that of a chimney. Or a controllable withdrawal of the outcominggas may be produced by induction. However, it is a fact thatthe thermal etiiciency is to a considerable extent a function of the free escape of the volatile products of the reaction. Thus, for example, if the ZnO-l-C reaction is carried the utilization of the energy which reaches the seat of the reaction may be said to tially close the top of the crucible andthe reaction will be diminished; again close the.

crucible and the reaction will cease, nor will any amount of energy, ordinarily applica ble, develop sufficient pressure to lift a comparatively thin, free, refractory plate. But

in the maintenance of or about atmospheric pressure care must be taken not to-cause an inflow of air to the reaction or the con denser chambers. Therefore the friction head in and at the register may be somewhat minimized by inserting free side linings, as bricks or blocks 56, Figs. 1 and 2, having numerous slits, as 57, and resting upon the resistor. In this wise,

a maximum, but pareven should the re sister become somewhat clogged, as with ashy residue, there will be opportunity for free escape of the fume and gas through these side slots and thence down through those portions of the resistor which, due to the blocks, will remain free. Again, the upper surface of the resistor may be composed of a layer of broken pieces of carborundum, as 58. This will serve to establish a chain of openings across the face of theresistor and immediately beneath the most intense portion of the reaction zone; also such an interposed layer would serve to somewhat insulate the carbon of the resistor from the charge, prolonging its'endurance. So, too, those portions of the resistor immediately beneath these side blocks may be formed of a mixture of carbon and carborundum or of relatively small pieces of carbon, whereby to increase the electric resistance along the sides and produce a higher temperature throughout the central section of the resistor bed.

Carborundum' (SiC) especially when recrystallized, is not subject to chemical attack-under the above noted conditions; it is highly refractory and will endure indefinitely. It is also a satisfactory material for the tamped lining 28 and for the grate bars, grate plates and such portions of the furnace where excellent refractory quality alone, or "where that quality combined with good heat conduction, are desired. All of the grate bars or grate plates can readily be reached from-the reaction chamber for examination or poking or for removal when the top section L is swung off, since the reach into the reaction chamber is quite short-.- Thus if thegrate bars or grateplates are removed, the septum plates 26 may also be taken out, thereby exposing the underlying condenser plates whose spaces may be cleaned Again, when the top section is removed side chambers J may cleaned if required. a

The advantage of being able .to inspect the various interior channels resides in the' fact that power. circuits are liable to fail and during such intervals the furnace may become sufiiciently cool to produce clogging,

or if the reaction capacity is beyond the liquefying capacity'of the condenser and the furnace 1S runaccording to the'former, then ficationof this averment,

, the manner shown,

ceptacle and the residue receiver,

some-portion of the. zinc fume will be re gained in the side chambers in the form of blue'powder? or as an oxidized conglomerate. I i

It will be apparent to those skilled in the art that various modifications, perhaps beneficial, can be made in the designand its elemental details without evasiop of the spirit arid essence of this invention.- Thus in justiit will suflice to point out; as follows: That in the instance say of the condenser plates 32, 33, they may be disposed precisely vertical or canted'in or a plurality .of back and forth chambers could readily be built, that is, in which the flow would be in a general horizontal directio Again,- t'lie said plates and also those shownin Figs. 3, 4 and 5 may be arranged in multiples, the flow being through a plurality of galleries; that is, in parallel instead of in series, in which case the contact surfacemight be the same, but the reversals and velocity of the fumeand gas would be reduced. Finally, having particular reference to Fig. 4, the septum may be formed to act both as the zinc reor the said interposed septum in place if required.-

the be inspected and "M1 matter, and termm whose wyhereby an increased area of contact 1spro her and resting upon portions of said septum may even be omitted, extending the grate plates downwardly to or iiite the present zinc chamber. Such a modification is feasible and operative and, together with various contingent details, has had due consideration. But theadvantages of using an have appeared to warrantits'employment, as for example, the surface of the zinc bath is kept cleaner and the'removal of residual matter from the interme diary chamber requiresa shorter suspension in the-operation of the draw it'together-with the bath from the 'zinc receptacle.

What I claim is:

1. In an electric zinc furnace, a grate.

furnace than to withupon which a bed-of-carbon resistor is sup ported, the resistor being arranged to act upon a charge when the latter placedin f the furnace.

2. Inan electric zinc furnace, a bed-ofcarbon resistor supported by spaced grate members forming a longitudinally extendfor receiving through the spaces-inert residals located adjacent to the ends of the grate.

- 3. The combination with a bed-of-carbon resistor, upon which a charge of resisting materials is sustained, of carbon terminals in inner .faces grooves are. formed,

ing grate underneath the same a chamber,

vided between the broken carbon of the re-' sistor andthe said terminals 4. The combination th abori zon'tal carbon resistor upon which a charge of reacting material issustained, of vertical carbon terminals whose lower inner faces are in con-.

loo

tact'withthe resistor whoseloutenfaces are l in contact with the end walls of the resistor chamber .and -whose upper ends are v'con nected by metallic electrodes. tothe powen.

circuit.

5. The combination with a horizontatcarcontact with the charge of reacting materials, the longitw dinal sides'of 'said charge being separated from the reaction chamber walls by; slotted blocks arranged adjacent to the resistor. .7. The refractory blocks disposed along of vertical carbon terminals faces which are the longitudinal sides'of the reaction chamm'fresistor. v

8. The refractory blocks disposed along the longitudinal sides of the reaction chamberand resting igion the resistor, the; lower oaks having openings for the resiston'whereby. the reaction surface is of less width than-the permitting-a sidewise escape of fume and gas from the reaction zone.

9. The combination with the carbon resistor, of a horizontal layer of carborundum upon the said resistor.

10. The combination in an electric'furnace with the reaction chamber and the resistor, of an upper removable horizontal section or zone in which the reserve charge chamber is contained."

11. The combination with a carbon resistor and a reaction chamber of a series of spaced members constituting the bottom of an overhead reserve charge chamber and providing a means through which the material in reserve may be controllably and intermittently fed down upon said resistor.

12. In an electric zinc furnace the combi nation with a carbon resistor and a reaction chamber, of an overhead reserve charge chamber whose bottom is provided with a series of movable spaced refractory members between which the reacting materials,

are fed.

' 13. A combined electric zinc furnace and condenser having the condensing system contained in that portion which is immediately beneath the resistor in the furnace.

14. In an electric zinc furnace, the combination with a reaction chamber, a resistor and a hearth upon which the resistor is sustained, of an underlying system of plates arranged to provide a plurality of ducts or slots through which pass the -votalized products of the reaction.

15. A zinc furnace having therein a reaction chamber, a-resistor, terminals there for and grate bars or plates for sustaining the resistor, said bars or plates disposed to form vertical slits or spaces to permit the flow of the volatilized arid also the inert residual products of the reaction from above so thatthey may be discharged in an underlying chamber or receptacle.

16. In a combined electric furnace and condenser a series of condenser members located beneath the resistor and arranged to provide slits or slots therebetween.

17. The combination with the reaction chamber, a resistor therein for operating upon a charge when placed in the chamber and a spaced sustaining grate, of an underlying chamber for receiving the products of the reaction.

18. In an apparatus for use in the metal lurgical processes, the combination of a resistor of an electric furnace, a sustaining hearth therefor, and beneath said resistor a member providing a chamber from which the inert products of the reaction may be removed through an opening or openings in a wall of the member. Y

19. In an apparatus of the class described the combination of a resistor, a section adcondenser,

j acent to and beneath the resistor, which sec- .65 tion constitutes the condenser, and an underlying receptacle for containing and collecting liquid zinc.

20. In an apparatus comprising an electric furnace of the resistor type, and a fume means providing a resistor hearth, a refractory septum disposed between the resistor hearth anda zinc receptacle, there being a passageway which permits any or all of the products of the reaction to flow from the reacting zone to the condenser and which also permits at least a part of said products to pass at least a part of said septum.

21. A section adjacent to and beneath the resistor of an electric furnace, said section containing a condensing system, in combination with an underlying receptacle for receiving the liquidized, the liquescent and the gaseous products of the reaction.

22. A condensing system disposed beneath the resistor, of an electric furnace, said system having spaced members, the lower ends of at least part of which extend into a bath of liquid zinc.

23. A combined furnace and condenser having a port or ports leading from a zinc receptacle in the lower part of the condenser, there also being provided longitudinal chambers, at least partof which are located in the furnace walls and into' which chambers the resdual gaseous product of the reaction primarily passes,and from whence it passes to the atmosphere.

24. In an electric zinc furnace provided with a condenser. the combination witha bed of carbon resistor, upon which a charge of reacting materials is sustained, passage ways for evacuating the volatilized products of the reaction, and. means for producing suction. whereby to approximately main tain atmospheric or negative pressure at the reaction zone.

25. An electric zinc furnace having a receptacle for receiving liquid zinc and provided with a flue or flues disposed beneath said receptacle for the purpose of controlling the temperature in the receptacle.

26. Condensing members such as plates, bars, blocks or the like for use in apparatus for condensing zinc fumes, provided with recessed or raised portions.

27. A condenser having plates, bars, blocks or the like, provided with recessed or projecting portions that are disposed obliquely to the flow of the volatilized products of the reaction.

28. In a condenser, plates, bars or blocks which are provided with sharp recesses or ribs disposed at an angle to the flow of the volatilized products of the reaction.

29. Condenser plates, bars or blocks provided with recesses or ribs and arranged so that the facing recesses'or ribs of adjacent This specification signed and witnessed members are in staggered relation to each this 31 day of December A. B 1912. bther.

30. Electric furnace grate -bars Or grate JOHN .3 plates whose upper edges are sloped and Signed in presence of upon which the resistor of the furnace is EDWINA. PACKARD, sustained. D.-HAn0Ln BUSH.

copie'l'ot thil patent may. be obtained for five eents each, iiy addressing the "Commissioner cfltentz Washington, D. C."

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