US1733138A - Cupola furnace - Google Patents

Description

Oct.- 29, 1929. F. A. STEVENSON CUPOLA FURNACE Filed Feb. 7, 1928 3 Sheets-Sheet Oct. 29, 1929. F. A. STEVENSON 3 2 CUPLA FURNAGE Filed Feb. '7, 1928 3 Sheets-Sheet 2 A TTORNEY Oct. 29, 1929. F. A. STEVENSON 1,733,138

Fled'Feb. 7, 1928 3 Sheets-Sheet 3 A TTOR/VEY Patenteel Oct. 29 1929 UNITED STATES PATENT OFFICE' FREDERICK A. STEVENSGN; OF NEW YORK, N. Y.,- 'ASSIGNOE TO ECONOMY METAL PRODUCTS CGRPORATION, OF NEW' YORK, N. Y., A CORPOBATION OF NEVI YORK CUPOLA FUR-NACE Application filed February 7, 1928. SeriaI No. 252506.

Reference is had to the accompanying drawings which illustrate the preferred form of the invention though it is to be understood that the invention is not limited to the exact .details of Construction shown and described,

'two sections of the supporting' ring used in the invention and shown in section in Fig. 2; Fig. 5' is a detal sectional View through a portion of the cupola, showng a modification of the specific mounting means for the rings 'forming a part of the cupola;

Fig. 6 is a sectional view showing a segmental form of ring;

Fig. 7 is a fragmentary front View of the particular type of segmental ring shown n Fig. 6; i l

- Fig. 8 is a tragmentary front view of the assembled rings;

Figs. 9 to 13, inclusive, are detail sectional Views showing various means of connecting the superimposed rings shown in Fg. 8;

Fig; 14 is a diagrammatic sectional view of the cupola of the present invention showing the ,alternate coke and ore beds; and

Fig. 15 is a fragmentary sectional View showing a modification of the supporting means for the lowermost ring.

This invention relates to cupola furnaces for use in the smelting and reduction of ores generally.

One of the objects of the present invention is the provison of a cupola of noVel design and Construction 'which will eflect great econonly in fuel.

Another object of the invention is the provision of a cupola whereinthe gas producer effect is reduced beyond that generally in existence in connection with the operation of the usual cupola.

A further object of the invention is the pro- Vision of a hot blast cupola in which the air is preheated in a zone above the combustion Zone whereby to reduce the temperature in the furnace above the combuston zone and prevent the absorption of carbon by the CO to thereby reduce the gas producer efiect of the cupola.

A still further object of the invention is the provision of a cupola having means 'or reducing the temperature in the shaft of the cupola above the combuston zone whereby to retain the fuel beds therein at a cooler temperature, more particularly a temperature such that a large number of the hcat units ot' the fuel will be preserved or retained in the fuel prior to the delivery thereof to the combustion or inelting zone of the cupola.

Another object of the invention is the provision of a novel design of cupola, the interier or shait of which is of successively decreasing diameter from a point above the melting zone to the top of the furnace whereby to aid in retarding discharge of the productions of combustion, thereby obtaining complete conbustion of the fuel in the melting zone of the cupola.

The invention also contemplates the substitution of a metallic lining or liner for a portion of the usual refractory lining; the metallic lining serving to de me in conjunction with the outer casing or sheathing of the furrrace, a heating chambe' for air which will absorb or take from said metallic lining the heat thereo'f, thereby permitting said metallic lining to absorb more heat from the shaft of the furnace and thus reduce the temperature in said shaft above the combustion zone of the cupola. to retain the fuel beds in this portion of the furnace at a reduced temperature, or a temperature below that normally found in the customary cupola of today.

The usual cupola, as is well known, has a gas producer efi'ect and the fuel layers in the shaft of the cupola are subject to intense' heat from the moment they are introduced into the upper section of the cupola, which temperature gradually increases until the fuel beds reach the nelting zone. lt is apparent that due to the heat to which the 'uel beds or layers are subjected a large number of the heat units present in the fuel are lost prior the utilization of the 'uel in the conibustion or nelting zone. These heat units go oil as waste and are usually a total It is the aim of the present invention to conserve these heat units in the tuel layer-s until they reach the inelting zone of the furnace, and it has been found that by reducng the 'temperature in the shatt of the cupola above the inelting zone the heat units are preserved in the tucl until they reach the Coinbustion zone. Actual tests have been made ot the hrrnace shown in the present application, and great economy in tuel ha been obtaiiied. lt has been i'ound that when the temperature ot the conibustion gases in the turnace is high, the coke charge required is proportionately high and it has further been found that when the teni erature of the conibustion gases in the furnace shatt above the n'elti'ng zone is reduced, the coke charge necessary 'or etlicient operation of the i urnace is proportionatelyreduced, and as the tenijierature of the conbustion gases in the shatt oi? the furnace above the melting zone is 'further and further reduced, it is obvious that still lesser anounts of fuel are required. This, it is believed, is due to the particular Construction and operation of the turnace of the present inventio'n, which is specifically described hereatter.

The tui-nace of the 'present invention comprises a Construction having, in eftect, separate zones, nain'ely, 'a ineltng or conbustion zone, a preheating zone just above the inelting `'zone in which the fuel and ore or other material are preheated prior to their entrance into the nelting zone, and a magazine above the preheating zone into which the layer-s ot 'fuel 'and ore are charged and where such layers are maintained at a teniperature belowthat present in the usual cupola or :turnaee whereby to prevent the less of heatunits in the fuel. This magazine might properly be terrned a cool zone, in contradistinction to 'the corresponding zone in the cupolas now in present day use.

In addition to the objects specified above, various other objects and advantages o'f the invention will be apparent to those skilled in the art 'froni the following description taken with 'the acconipanying drawings in which, referring specifically to Fig. l, 2 designates the enter casing or sheathing of a cupola which is nounted On a suitable base 4:, and is provided with charging doors 6 or a chutc 8 'tor the sane purpose; the interior of 'the casing 2 being provided at its lower portion with a refractory 'lining 10 which extends upwardly soinewhat above the usual nelting zone "of the eupola.

The casing 2 is forned of sections 12 and 14 which are secured together in any suitable inanner and may be so Secured as to permit erpansion and contraction thereof if desired.

in carrying out this invention, I substitute for the retractory lining, which is usually continuous from the base to 'the top of the furnace, a lining indicated generally at A spaced froni the casing 2 and formed preferably of a plurality of superimposed metallic sections B provided with radially extending external fins or corrugatins 24:, each of which is continuous around the sections; the sections being securely but detachably connected 'together as hereafter described. The several sections torming the lining B are in the ;torin of rings and 'orclarity 'they have been designated as 28, 28 ai'd ?30,irespectively, the rings each being provided with internal vertical corrugations or ribs 32.

lteterring particularly 'to Figs. `1, 2 and 5, it can be seen that the upper inner edge 'of the retractory lining lO is cut away to receive the depending lower edge of 'the lower-most ring 26, the ring being provided with a laterally exrending supporting *fiaige 3& which s ats upon and is supported by the horizon tal ot a supporting angle indicated gencrally at C.

The Ting 'C is composed of a plu'rality 'of arcuate segmente and, referring to Fig. 2, ea li thereot includes a vertical leg 38 and the before-inentioned horizontal leg 36; 'the vertical leg being Secured to the casing 2 by ineans of bolts 4:0. The refractory lining 10, more particularly the upper surface thereof, is provided with an annular recess in which the horizontal leg of the supporting ring-is seated, the latter extending to a rib 42 defined by the recess and by the cut away portion of the inner edge of the lning. Obviously, the segments of the supporting ring are ange segmente, the sane being arcuate in form, and at each end there'of said segmente are provided with webs 44 which abut each other when the sections are assenbled, as clearly shown in Fig. 3, the assenbled segniente defining the supporting ring heretofore nentioned with the webs extending froni the vertical legs 38 of the angles to the horizontal legs 36. The horizontal legs 36 extend to and preferably contact with the rib 46 of the refractory lining 10, and ti'e rods 48 are used 'to 'connect the severaljsupen irnposed sections, `the lower ends `of the tie rods extending through the `fiange 34: ot' the ring 26 and 'through the horizontal leg &36; suitable nuts 50 being eni'ployed tor securing the tie rods in position in an obviou's-'In'an'- ner.

Fg. 4 discloses a detail View 'of adjacent angle segmente, and 'it can 'be seen in said figure that each angle is providedat one end with 'a depending supporting lug 52 upon which is seated the end of the next'adjacent angle. i

Fig. 5 shows a slightly different type of connection, although the Construction of the lower end of the ring 26 is identical with that shown in Fig. 2, the same having the lower extension and the lateral supporting flange 34. The angles which make up the supporting ring shown in F ig. 5 are shown as being forned with a horizontal supporting leg 54 which extends to the rib 42 and with a depending leg 56 secured to the lower sheathing section by means of bolts 58. As shown in this figure, tie rods 48 are also provided which extend through the supporting flange of the ring 26 and the horizontal leg of the supporting ring and have securing nuts 50 at the lower ends thereof for an obvious purpose.

The rings 24, 26 and 28, as clearly shown, overlap each other; the rings 26 and 28 overlappingly engaging at their lower ends the rings 24 and 26 respectively, this construction being designed in order that there will be no lodging of particles of either ore or tuel in any of the abutting or'meeting surfaces within the shaft of the furnace, as will be apparent.

The metallic lining B is, as shown, spaced from the sheathingof the furnace, and defines With said sheathing a heating chamber indicated generally at D which is divided into a plurality of sections (three, in the present instance) by means of battles 60 supported by the rings at the juncture of adjacent or supermposed rings. The battles extend to the casing or sheathing 2, and if desired may be secured to the latter in any suitable manner. Adjacent the ring 26 an air intake 62 is provided, and the battles 60 are provided with oppositely arranged openings 64 to permit air to pass throughithe heating chamber sections in a zigzag or circular path to a conduit 66 connected to the air belt conduit or wind box 68 surrounding the outside of the furnace and registering with the tuyres 70 therein. The this have been described as extending laterally from the rings 26, 28 and 30, but it is to be understood that within the spirit and scope of the invention each ring may be provided with a continuous spiral fin, if desired, whereby to impart a cyclonic effect or movement to the air admitted through the intake to the heating chamber. The uppermost ring 30 is provided with a laterally extending flange 74 which bears against a sealing plate 7 6 supported by an angle 7 8 secured to the casing 2, and the upper ends of the tie rods extend through the fiange 74 and through the plate 7 6 and are locked by means of wedging keys in an obvious manner. The upper edge of the ring 30 supports a metallic ring 82, which I term a false ring the latter extending to a closing plate 84 and being secured thereto, if desred, in anysuitable manner.

' As before-mentioned, the rings 26, 28 and 30 are internally corrugated and externally ribbed, the .external ribs being of substantial size whereby to provide as wide a Contacting area for the air in the heating chamber as is possible. If desired the rings 26, 28 and 30 may be provided with external vertical ribs in lieu of the laterally extending ribs, the ribs, whatever may be the arrangenent, serving as heat radiating surfaces and also as strengthening elements.

The description just above pertains generally to the cupola of the present invention, and the specific details will be fully described hereinafter. It is deemed advisable at this time, however, to briefiy set forth the operation of the cupola, and, referring to Fig. 1 and also to the diagrammatic Fig. 14, it can be seen that, as is usual, alternate layers of fuel such as coke or the like and ore are charged in the shaft of the furnace, the layers of fuel and ore being designated as 86 and 88, respectively in Fig. 14. The conbustion or meltingszone of the furnace is, of course, just adjacent the tuyres. The ordinary cupola leats the fuel the entire length of the shaft and, indeed, takes from the fuel a large number of heat units thereof prior to its reaching the melting zone. In the furnace of the present inventionlit can be seen that air entering the lower section of the heating chamber through the air intake strikes the ribs or ns of the ring 26 and is heated, taking the heat from the ring. In a 'furnace of usual Construction-that is, one in which the refractory lining extends the full length of the shaft-said lining takes the heat from the shaft but retains it, thereby maintaining an intense heat in the entire shaft of the furnace; no means being provided for taking this heat from the refractory lining and permitting the lining to take up more heat from the shaft of the furnaee to reduce the temperature therein; The furnace of the present invention provides a metallic lining which is formed of a special kind of metal, the particular metal, however, forming no part of the present invention in detail and therefore not being definitely stated, as obviously many kinds of metal may be employed which will have the characteristics necessary in carrying out the thought of the present invention. It is necessary, however, to provide a metal which will be heat conductve in order to take up heat from the shaft of the furnace and permit the air to absorb the heat from said metal. The metallic lining is, of course, constructed of material which will withstand high temperatures and is so formed as to permit expansion and contraction thereof without cracking or fracturing. The air entering the heating chamber takes this heat from the metallic lining, thereby permitting said lining to take up more heat from the shaft of the furnace above the melting zone, and this operation continues during the operation of the furnace. It will be apparent, therefore,

ments 120 and 128 have been described as rings, but it is to be understood that within the spirit and scope of the invention a plurality of relatively short looking keys may be enployed in lieu of a locking ring, thepurpose and function of such short keys being the same as the purpose and function of locking rings. The Construction disclosed in Fig. 13 is more particularly applicable to the type of ring shown in Figs. 6 and 7 and hereina'fter described, but for the sake of uniformity the description of this figure (Fig. 13) has been associated with the description of the remainder of the figures on this particular sheet of drawings which all pertain'to the connections of superimposed rings.

It has been found that it is not always necessary to connect the superimposed rings by means of tie rods, as evidenced in Fig. 8, but it is desirable in a furnace of the construction shown wherein the superimposed rings are not connectedby tie rods, to position the lowermost ring on a plate 107 which is seated on the upper edge of the refractory lining, as clearly shown in Fig. 15, and which is provided with an inner annular recess 111 for centering the lowermost ring; the rings 26, 28 and 30 thus being centered in spaced relation to the outer casing.

Referring now to Figs. 6 and 7 which figures disclose a modification of the construction of lining rings, it can be seen that the rings which have been designated as 131 and 133 in these figures are superimposed one on the other, and ring 131 is provided with an undercut surface 130 which really defines a depending rib 135 and the upper surface is provided with an annular rib 132; ribs 135 and 132 being adapted to eXtend into annular recesses formed in the supporting plate 142 and the lower end of the superposed ring 133, respectively. Each of said rings comprises a plurality of arcuate segments 134, shown clearly inFig. 6. The segments 134 are corrugated as at 136, and the ends of adjacent sections are providedwith compleinental recesses which receive locking pins 138 for tying the several sections of the rings together in an obvious manner. To prevent accidental displacement of the superimposed rings, tie rods 140 are employed which extend through a supporting plate 142 mounted' on and supported by an angle 144 secured to the sheathing in any suitable or desired 'manner and which may be embedded in the refractory lining 10. v

From the above description, it is believed the operation of the present invention will be fully apparent to those skilled in the art,

but itis desired to state that when air is adnitted through the intake into the heating chamber the air. will pass from the charmber through theconduit from where it Wlll be delivered into the air belt and then to the tuyres; 'the air in its passage through the heating chamber being intensely and uniformly heated as before described. Attention is called to the fact that the shaft of the furnace tapers upwardly from the lowermost ring 26 to the top of the furnace; all of the ringsin the shaft being of successively de creasing diameter, and this results in a choking of combustion within the furnace, thus eifecting complete combustion of the fuel therein and a consequent saving thereof and a distinctly more efiicient operation of the furnace. Further, and as before-mentioned, the provision or substitution of the metallic lining within the furnace for a portion of the usual refractory lining serves to eifect a reduction in temperature in the furnace shaft above the melting zone, thereby reducing the gas producer efi'ect of the entire furnace and a resulting preservation of the heat units in the fuel until the latter reaches the melting zone, thus affording a greater ratio of fuel than has been heretofore known.

Attention is called to applicanfis construction of furnace in that there have been provided really three distinct zones in the furnace: the first zone I term the melting Zone which is just above the tuyres; the second zone is what I term the preheating zone and extends from the' melting zone upwardly to about the upper edge of the refractory lining and wherein the alternate fuel and ore beds are preheated until they reach the melting zone; and the third zone I term the magazine, said zone being that encompassed by the metallic lining and wherein the fuel beds and ore beds are maintained at a reduced temperature whereby the heat units in the fuel beds are conserved preventing loss thereof.

What is claimed is: a

1. In a cupola furnace having an outer sheathing, refractory lining at the lower portion of the sheathing, and a plurality of superposed internally ribbed metallic rings of successively decreased diameter supported by the refractory lining and arranged in spaced relation to the sheathing to provide an air heating chamber, the Contacting surfaces of adjacent rings being so fcrmed as to be interfitting whereby to permit individual eXpansion of said rings, and detachable means for securin'g the rings together.

2. A cupola furnace having an outer casing, a refractory lining at the lower ena of the casing, and a metallic lining in the upper portion of the casing arranged in spaced relation to the casing and defining With the casing a heating chamber, said lining being formed of connected segments, and means between adjacent segment ends and'contacting therewith for retaining said segments in assembled relation. u

3. A cupola furnace having as a portion of' the .lining thereof a plurality of metallic rings interfittingly connected together in superposed relation 'whereby to permit indi- Vidllld expansion thereof, and an onter shezthing, the inner surit'ece oi" said rings heinz vertically rbbcd and the enter surface ot' seid ringe being letereliy irihhed and epeced froni the shcething of the turnnce to provide en :lir heating chanher.

41:. in a cupole tui-hace, the combinetion with e sheething and retrectory iining edjeccnt the lower end thereof, of a neteliic iining supported by the refrectoryiining and comprising eplurality of supernposed metallc ring's of successively decreesing di &meter nterfittingiy connected together to pernit individual` expension of said rings and having their outer weiis spaced from said sheathing to detine an air chenher.

5, In e cupol furnace, an outer sheathng, refractory lining material edjacent the lower end of the sheathing, a supporting element cerried hy theretrectory material, {L piurehty ozt superposed neteliic rings supported by the supporting element, the lower-most ot which is centered on the supporting element and the upper rings being connected together in interfittingreletion, end tie rods for retaining seidrings connected relation.

6 In e oupohp UIILELCB, an-outer cesng, a plnrality ofsuperposed metallic ringstornngtheiining of the furnace sheft above the nel tng` zone thereot and detining with the o l ter cesing s chemher forreceivingeir to be heated by heat absorhed bythe ineteliic linington the-edj &cent portionof the urnace shutt Whereby to reduce the temperature in the shett adjecent the neteilic lining, and means extending between the upper and lower 'inrs to reten the metallic Iining` in assembled reletion.

7. A cupola furnace eomprising e shatt, en outer sheething, e metallic member at the upper` end of the shatt and entending ndjecent the cherging'doors thereo't' and forniing u part only ot the lining of the shetit, seid member being forned of e phreiity of Overleppingly connected snperposed rings with upper rings overlapping the lower rings Whereby` to permit eXpansion ot the lower rings relative to` the upper rings; under the influence of hoat. i

8; In, e cupola furnece, en outer sheething, :i retrectory lincr at the lower end' ot' the turnece having its npper end circmnterenti tlty receseed, a, supporting element nonnted on the noper edeje o't the ret'eocor Einer. :i netaltio liner spported on the supporting element` and position ed by the cireumterential recess; seid 'liner defining, with the enter eheztthing, 21 heatingchenher tor air, e sealing pinte-for closng. the upper end` of the i heatingchunher` and tie-rode in the heating chenber extending between the. supporting element end scaling. plate for. retening the meteihc lner n poston.

1. 1: i` up e ur a e, n u he-r ime,` e retrecto'y Imer t the lower end' of the turnece and having :1` recessed npper edge, a. neteilie iiner supported by the retractory liner end defining, with the onter sheathing, en air heating chainber, seid liner comprising a lower ring supported in the recess in said retractory liner and upper rings supported hy said lower ring, ar scaling plate between the. sheathin end uppernost rings to close the upper end of the heating chemher, end tie-rods connected between the lower and nppernoet rings tor reteining the liner rings in assenbled position.

10. In e cupoie tnrmce, an outer sheeth-` ing, refractory liner at the lower end of the fnrnace, an annuler support on the npper surface ot the refrectory lner, a, netel lner supported hy seid support and comprising a plurelity ot' snperposed rings interfittingly connected for pernitting individual expeneion ot seid rings and defining wththe sheathing a chanber receiving etmospheric air to he heeted by heat fronthe furnece sheft absorhed by said metal liner, a eeelin plate closing the upper end of seid cheinbelf, and means in the heating chember engegng the metal lner for retaining the letter in as: senhled position. e

ll. A cupola turnece having es a portion. ot' the linin thereofe phrality of inetallic rings interttngly connected together insuperinposed reletion whereby to Permit indi- Vidnal expansion thereof.

12. A cupola turnece having as e portion OI" the lining thereojt e phrelity` of super-r posed netalhc rings interfittingly connected together to permit individual expension thereot end each formed of e plura-lity of connected segnents.

13. In e cupola furnace, .e metallic nemher as a part of the fnrnece lining and detin-` ing one well of an air heating chn nher, said liner comprising aplurelity of segments erranged end to end to define a ring, and means. between adjacent ends d Contacting there with for retainng seid segnents in assembled reletion.

14. A cupole tui-hace hevinges :L portion of the lining thereo' e netellic ring formed of :L plnrality of segmente, and connecting ele-` nents between adjacent segment ends. and held therehy for connecting the segmente together and for retaining them in assenhled position.

15. A cnpolz furnace havingas portion ot' the liiing' thereof; a` netellic ring tor-med ot' {L plurelity of segnents, and ccnnecting, means at the juncture of edjecent segment ends and held in position thereby tor. connecting the segmente together and for re: te inin them in ;ssembledipositionf 4 16. In e cupoie turnece, a n onter sheath-r. ing and e netellic member formin; pert: ofthe-'nrnace liningend defining ne'weil of an air heating chamber, seid metellic m m; her eonprising a piumlity &segmente; aii?.

ranged end to end to define a ring, and connectng means independent of the sheathing arranged at the juncture of adjacent segment ends and held in position thereby for connectng the segments together and for retaning them in assembled position.

In Wtness Whereof I have hereunto set my hand.

FREDERICK A. STEVENSON.

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