US2338175A - Blast furnace - Google Patents

Description

R. M, GIBSON Jan. 4, 1944'.

BLAST FURNACE Filed sept. 25, 1941 4 Sheets-Sheet 2 J M M M ATTORNEYS R. M. GIBSON BLAST ,FURNACE Filed sept. 25, 1941 Jan. 4, 1944.

I from the furnace near the top thoughlleneathl Patented Jan. v4, 1944 UNITED STA-Tus* PATE-Nr oFFicl-:

This invention relates to blast furnaces and to" smeltingfurnaces generally that operate on the principle of the blast furnace, andconsists 1inV refinements of structure, in consequence of which,V furnace operation' is subject to more extended and accurate control; operation is simplified,

expedited, and rendered v,more uniform; econo1\\ I mies of operation' are realized, waste is diminished, and the product improved in quality. The invention involves also improvements in method of operation. The application is a continuation in part of an application filed by me May 31, 1940, Serial No. 337,985. i a y Y In the accompanying drawings Fig. I is a view ,n in vertical section `of va blast furnace, of typical form and structure,in which the features of my invention are embodied; Fig. II is a view to larger scale showingfragmentarily and in vertical section an upperportion of the furnace wall in it, Fig. III is a view in horizontal section, on the plane indicated at I II-:-IIL Fig. II.v Fig. IV

.is 'a front elevation of .,theassembly,v of parts shown 'in Fig. II.y Figs. V"'X illustrate an em bodiment of the invention inm d'fie f rm. Fi "5 Screened mouth' theport tam outwardly (from o 1 d o 'g right to left,1Fig. II) toacircular section, approx V is a view in' vertical section through the upper part ci' the blast'v furnace and corresponds to the showing afforded in` Fig. II. Fig. VI is ya view in horizontal section on 'the' plane indicated at yVI-IVI, Fig. V. Fig. VII is a view in front elevation'f of an oil-take louvre unit. Fig. VIII is a view of the same unit in side elevation. Fig. IX is a fragmentary view in horizontal section through the furnace wall and showing the louver unit in plan from above. Fig. X is a view on yetV larger yscale showing in horizontal section the damper and themeans for adjusting it. The essentially columnar blast furnace I o circular horizontal cross-'section (Fig.,I) is providedy at its otherwise open top with a charging` bell 2, and at its base with a .draw-off port 3; y near the base tuyres', 4 arranged incircumferential succession extend through the walls, and y the bellleads the bleeder pipe 5 4to the stack.

The furnace substantially filled with ,the material of the charge is maintained in prolonged o and continuous operation; `molten, iron isr fromtime to time withdrawny at 3and the charge of raw materials is maintained by intermittent introduction through the bell-controlled top. The

height tofwhich the charge rises'within the furnace varies; and in Fig.V II the range is vdiagrammatically indicated by two broken lines that bear 55 piezometer ii, the temperature, the composition v the legends., Stock line (low)"y and Stock linef l (111811)." V

' My invention consists inthe provision atthe upperv end of the furnac'eyand preferably 1m- 5 mediately below the level that marks the .lower f vlimit. of the normal rangein the height of the by a damper 8.

'i In'the installation illustratedbyway of exam l5 ple in Figs. II, III, and IV the furnace atthe level of `these gas ports, is y 'feet in internaldiameter and 28 feet in external diameter; the

ports are ,sixteenin number; `and each forms part of aunit (more particularlytov be described) andthe structure of my invention in place with- 20 that i5"3 'feet Wide and aDPlOXmly 9 feet high. i

The port itself has ay mouth of the oval shape shown Lin Fig. 1v, that is v:a feetsinohes high and,2y feet l104 inches widel y The mouth of the 'port is screened bylouvres 6i'. From the oval imate1y`2 feet` 71/2inches .in diameter. At its outer end the "port isA continuous with the `down-,-

comerl of equal internal diameter. A damper is conveniently set at the outer end of the porty B,

and takes the form of a butterfly valve, rotatable zone arranged ,and adapted both to the sustaining of the charge andto the escape of gas; and

that resistance to therfree flow of\gas may be, varied irreach port relative to thepthers. n

40 Itis manifest that, by the provision of apinrality ofgas ports circumferentially arranged at the upper end lof the furnace, and by the proviy sionv of dampersfthat control gasv flow through such portsseverally, the draft conditions' within the furnace andthrough the furnace charge may becontrolled andl varied, to afford compensation and correction of irregularities that develop as furnace operation progresses; and it is manifest that such control is gained without ,diminution ,50 of thevolumes -of air that enter the A`charge through the tuyres at the bottom of the fornace.

` By placlngin the stream of gas that ilows through each port proper testing apparatus, vsuoli asv a' thermocouple 9, an Orsatt apparatus l0, and a charge (the level vrdefined at L by the Stock lineV ilowl")f a succession of circumferentially arranged gas ports 6 that lead horizontally through l0 the furnace wall, that severallythrough down-l comers 'Il 'communicate with "the stoves (not shown), and that severally are controlled, eachr (and particularly the ratio ofCOto CO2). and

the volume of the emerging stream may be specally indicated In Fig. II by a nozzle |10. This ciflcally observed, and comparison of conditions yin the several streams ywillI adord the operator advice, that he may marke suchxvalve adriustments as will maintain optlrniuny through'the furnace charge'. c l Further features `of inventlonare found in the specifl';.forni` and refinements ofy the stockline armor'fthatlforms; of the installation here vconsinora-oz draft n 1 injected water wets the circumferential portion 1 (andthe :circumferential portion only) of 'the'y charaeilandthe'material descends inwet condii "tion across'the louvre-screened mouths of portal.,` 'The' streams of gas' as they ynow-tothe portsy carry fine and powdered material of the `furnace charge, and the hier 'that descends across the face offthe ports acts and with this stock-une: armo'r the .j

. EBS p 'rtsjare structurally in units, that are" applicable, to and'removable from i their plaoesiini the 4'lui-nace structure.

The stock-line the name implies, a belt oi' resistant matetiulfbuilt Within the iurgnaceat the stock line',ando f"a material such as f toendure the grindingactionof thein-afod mate- ,rials that'make up the furnace charge more effectively than the brick of whichthe furnace walls k.elsewhere are formed.

` made up ofa plurality of `sections I2 resting upon astepf It (Fig. Informed in the masonry of of' this instauauon is the `furnace wall, bolted together as indicated at (Figml 'to form a circumferentially continuousbelt A`The armor extends throughout the l range'. ofl .normal variation of the stock line .(be- I the-'lpointsL-'and'fim II) in an obliquely g surfaceis-so. disposed as to sustain in'"solistantiollylperpendicular direction impact' upon itfof in-fed vcharte matenel., wenn substantially the level, indicated by "the point"y L. Fig. II, -the belt of armor extends *downward and the face of this downwardly extendedportionv is vertically disposed. This downwardLv' extending poi-lon of the armor belt covers the region inv which the air ports are placed. 'I'he sections of the armor correspond in number with .the air ports each armor section is windowed, as at I6; and through the window of each armor l section extends one of the 'air ports 6.

Through the upper portion of the belt of armor, and in the portion which in normal operation lies within the range of stock-linevariation (between points L and H, Fig. II), extend orifices IO in which may be set instruments for detecting the approximate point within the range, at which the stock line at any particular moment lies. This may be accomplished by placing within the orifices terminals of electricircuits, so arranged that the circuitsare completed only through the body of stock lying upon `the face of the armor belt. Suitable detection instruments will be responsive to currents flowing in circuits so established. In Fig. II I have shown in o ne of the orifices i8, a' suitable detecting instrument which includes an electrode |20, of metal surrounded by a tube I2I of suitable insulating material such as porcelain. The electrode tip projects intofthe furnace to contact the body of thedescending charge. and the opposite-end is connected in .as afilter. arresting such une, material, preventling its escape on the gas streams, and carrying it to the reaction zone in the lowervpart of the 'I'he sections I2 of the stock-line armor and the gas ports B are conveniently made as castings,

preferably of 0.50 carbon, cast steel, and their lcumferentially continuous belt.

circuit through lead |22 to any suitable indicating' apparatus such as a light |23 which in turn is j grounded to the armor belt. In practice a number of such indicating arrangements are spaced around the periphery and serve to indicate the height of the stock line and whether the stock 1 line is level.

Below the line of the lowest of the ports I8 n and above upper edges of the windows I5, the

belt of ,armor 'is .penetrated by a circumferential row of ports I'I, and through the ports I1 iets of water are projected. -Means for projecting jets of water through ports I'I are diagrammati- Y designs are such as to aiford a structure free of warping. The furnace wall is ported at It, and through these ports (or, if preferred, through the open top of the furnace), the sections I2 of the stockline armor may be introduced and brought to position, and then bolted together, to form a cir- 8 may be introduced in and secured in place in the windows IB when stock-line armor hasbeen applied. The downcomers I are independently secured to the furnace structure, and the ilanges 2l of the uppermost portion of downcomers `I c are extended to form complete closures externally v of the ports It. Internally the ports are covered by the armor belt.

The stem II of damper l may beturned by I means of a hand wheel I9. A block within a casing 20 may be rotatable on the axial line of stem il, and rotatable in response to the 'turning oi the hand wheel, and the connection between the block and the stem Il may be such as to allow relative movement in the direction of the axis of the stem, while effecting rotation of the stem in response to rotation of the block. In such arrangement tolerances are found for slight departures from minute accuracy in relative positions, whether those incident to assembly. or those consequent upon thermal expansion and contraction.

Turning to the embodiment of the invention that is illustrated in Figs. V--X, the furnace wall in its upper portion is made hollow, to afford the annular off-take chamber 22. This chamber constitutes a manifold for the off-take pipes or downcomers 23, which lead therefrom. Into this oir-take chamber and in its lower part' the gas ports from the. furnace chamber lead. These gas ports are screened by louvres 24. The louvres are formed of sections, and the sections extend in side by side arrangement circumferentially of the furnace, filling an otherwise substantially continuous orifice through the furnace wall to the oil-take chamber 22. As in the structure r'st described, these louvre sections are preferably made of cast-iron. In such a structure as is illustrated in Fig. V, the vertical spacing between the louvre plates may advantageously be' two inches, and the total area of the louvre space should preferably equal or somewhat exceed the internal cross-sectional area of the furnace shaft, and the louvre structure is made of sufllcient vertical height to anord such proportions. Figs. VII, VIII, and IX show a louvre unit or section. This unit comprises three vertical rows of louvre cells C. deilned by vertical stitiening ribs 25, and framed between two end posts 26 that preferabb' are provided with extensions 21 and 28, by which The gas ports X assura is indicatedxin Fig. V, wherein the sloping ,downwardly from the .side wall of the furnace chamber, or hold toward Athe center thelgof. f.

It will;be noted ,that the annular off-take chamber 22 extends a considerable distance above off-take pipes 23 have egress from this chamber at a higher level than, the highest louvre space. The reason for having the louvres at all times the damper is drawn fullyiaw'ay 'from vits corresponding louvre unit. -In `the drawingsllig. V)

each damperjunit is shown'tobe providedirwith l vtwo adjusting bolts, .but they number may. of

ythe upper limit of the louvre cells, and that the below the stock line, is to cause the gases about I to leave theJurnace to pass through the smelt-4 ing stock just introduced, in such manner that this stock will act as a constantly renewed filter medium, to take from the outstreaming gases in more or less completeness the dust and fines that otherwise would escape. i f l It is generally recognized in the art that a uniform distribution and ilow of the gasesthrough the 4smelting stock of the furnace improves Athe eiiiciency, and therefore the capacity, of any fur- Such uniform distributionis, however, difficult to maintain, because. ofthe unequal porosity of the chargeef-and, af'v pipes-1f l nace of this character.

tendency existstoward the formationof (that is to say, localized lines of draft) in the charge that is in course of smelting.. Excessive velocity of the gaseous products of the smeltiiigAv operation along the inner wallof the furnace, is 1 liable prematurely to burn out the lining thereof,

with the consequence that time and expense are' wasted'in making repair. Such excessiveand localized drafts may to a certain extent-be re.

so duced or corrected, byselectively vdiminishing'y the ilow of air through certain of the tuyres.

Such control, however, is done with diminution of thetheoretical capacity of the furnace, since diminution of air, means diminution in the mag-- nitude of the essential reducingoperation.

Excessive velocity of thev gaseous streams within the furnace charge, and particularly along the inner walls of the furnace where it is most detrimental, is in the furnace of my invention in both of the forms that are here shown, controlled by means of adjustable dampers. In the shown in Figs. V-X; for each louvre unit 3|y ya damper 32 is provided. This damper is arranged externally of the unitof louvre plates and within the o-take chamber 22. Itis 0f substantially the height of the vunit oflouvre plates, and is curved to correspond to the curved formation of the louvre unit, which in turn is curved in conformation to the curvature of the furnace wall. These dampers 32 are adjustable on the form tions within the furnace; he is able to detect irregularitiesof operation; and immediately to radial lines of the furnace, and by such adjustment eiect variation in ythe effective areas of' the individual louvre units. Various means to operate these dampers will readily suggest themselves. The drawings show threaded bolts 33. hingedly secured to the outer face of the damper as at 34, and provided with threaded wing nuts 35, rotatably mounted in split bearings 36, secured in any desired manner, such as by welding, to the outer shell of the yblast furnace.v Preferably the nuts and Vbearings are provided vwith labyrinthine cells 31 to reduce leakage to a minimum. The wall of the furnace is recessed at 38 to receive the hinge connections 3l when i this finely charge.' y,frnljs onditioni'jcombied wanna V.trol obtain'a lef-br course,` be,y varied to suit `thesize of the damper unit. facilitate'. the operation lof lthe damper units ahdntorelieve the adiustinfbolts of the weight of 'the damper units, `thes e u nitsfrestupon iron saddles I3 suitablymountedqonfthe outer wall of theI oirta'kechanibjergll. surface upon whichthesddlesrestisteeplr inclined in# L wardly,fsofthatdustffalling `thereon willreturn to the furnace hold.-

When a blast-furti A more oiI-takejpipe's, itf-rnay .be'ftmndr desirable'-1to subdivide the annul'aroi-ltake chamber into sec tions corresponding-innumberlm the nuxriber of 40, `to prevent the! formation of-foross' currentsl i witninvtne vofftake chamber, andfthus t'o'fanord better distribution of the outflowi'ng gases to ythe off-take pipes g, r downcomers.

responding offt'ake'pipe its o 4e viru'i divides? ma more dense, Avand this diminishingthe i 'ten 'pipeszor lo viii' the furnace 'operator to" maintain 'a if body'of the charge (and the.l tuyre "control'gqthan may fotherwi'sebefachieved.

The `stiuct'urcof`-Fig".'Y includesalsofeature's zof conventional design thathave not been described j in detail'. y'Iliey are 'generally known inv the art. V and 'V' are vents; v are the butterfly-v valves for the' furnace; H is the furnace hoppelfi f H lis the gashood thereof; and B is the' charging bell.

of reaction of high efllciency'and of an intensity well distributed throughout the. breadth of the furnace. 'In operation the attendant by observation of the instruments,` has knowledge of condimake correction. The lines are'in a large measure carried to the reaction zone. and the loss formed of a' plurality oi' sections mounted on the' furnace wall and united in a belt and covering on the inside the ports in the vfurnacewall. each section of suchfbelt .of armor being windowed, a

plurality of gas ports set .one in each of the windows of the belt of armor, a plurality of.

downcomers each covering on the outside one of the ports'in the furnace wall, with which 1 downcomers the gas portsare in `the ,assembly severally 'in communication, and means for regulating ilow through each gas port severally.

isproyided withk two: or 4 The arrangement is such as to maintain a zone V` f the ports severally.

2. In a smelting furnace of columnar form adapted to be charged from above and aerated at the base, with walls adapted to sustain a furnace charge, a belt of stock-line armor mounted on the furnace wall near 'the upper end of the column, and including an upper portion with inclined surface and a lower vportion with vertical surface, and a plurality of gas ports extending through the furnace wall and through the lower portion of stockline armor, and arranged in circumferential succession around the furnace wall, the said belt being provided in its upper inclined portion with horizontally extending ports arranged in vertical succession and adapted to receive means for detecting the position of the stock-line from time to time inthe course of furnace operation. V

3. In a. smelting furnace of columnar form adapted to be charged from above and aerated at the. base, with walls adapted to sustain a furnace charge, the invention herein described,

which consists in the provision of a plurality of gas ports arranged circumferentially of the furnace wall, and opening through the furnace wall adjacent the top of the column and below the normal stock line, and forming in the furnace wall a ported zone, gas-penetrable charge-sustaining means arranged in each port, and means for regulating the flow of 'gas through the ports severally. v-

4. In a smelting furnace of columnar form adapted to be charged from above and aerated at the base,` with walls adapted to sustain a furnacev charge, the invention heerin described, which consists in the provision of a plurality of gas ports arranged circumferentially of the furnace wall, and opening through the furnace wall adjacent the top of the column and below the normal stock line, and forming in the furnace wall a ported zone, a bank of louvre plates arranged in each port adapted to sustain the furnace charge and to permit the escape of gas, and means for regulating the flow of gas through 5. In a smelting furnace of columnar form adapted to be charged from above ,and aerated at the base, with walls adapted to sustain a furnace charge. the invention herein described,

which consists in the provision of a plurality of gas ports arranged clrcumferentially of the furnace wall, and opening through the furnace wall adjacent the top of the column and below the normal stock line, and forming in the furnace wall a ported zone, gas-penetrable chargesustainingmeans arranged in each port, means for regulating gas flow through the ports severally, and a succession of water injection ports circumferentially arranged in the structure at a level higher than the gas ports.

6. In a smelting furnace of columnar form with walls of masonry having an annular olftake chamber formed within the walls and at the upper end of the column, an oiItake pipe with which the oiftake chamber is in constantly open communication, and a plurality of outflow apertures arranged circumferentially of the columnar furnace and leading from theA hold of the furnace to the said offtake chamber, the invention herein described, which consists of individual and severally operable flow-controlling means associated with each of said outow apertures.

7. In a smelting furnace of columnar form with walls of masonry having an annular oil.'- take chamber formed within the walls and at the upper end oi' the column, a plurality of oi!- take pipes with which the offtake chamber is in constantly open communication, and a plurality of outflow apertures arranged circumferentially of the columnar furnace and leading from the hold of the furnace to the said otake chamber. the invention herein described, which consists of partitions subdlviding the ofl'take chamber into a circumferential series of chambers the said offtake pipes being severally in communication with different chambers of such circumferential series, and the said outflow apertures leading severally to dlerent chainbers of such circumferential series, and severally operable flow-controlling means associated with 4s each of said outflow apertures.

ROBERT M. GIBSON.

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