US372912A - Gas blast-furnace - Google Patents

Description

(No Model.) 4Shets-Sheet 1.

J. H. HILLMAN. GAS BLAST PURNAQE.

7 No. 372,912. Patented N0v.8,1887.

WITNESSES INVENTOR ATTORNEYS.

N. PETERS. Fhulo-Lllhognphcr. Washington. 0.0..

(NoMo'd leli) 4 Sheets-She'd 2.

- J. .11. HILLMAN.

GAS BLAST FURNACE.

No. 372,912. Patented Nov. 8, 1887.

WITNESSES INVENTQR ATTORNEYS.

N PETERS, PhubLilhugnphqr, Washington. n.c.

4 N A M L L I H H J (No Model.)

GAS BLAST FURNACE.

No. 372.912. Patented Nov. 8, 1 887.

WM F INVENTOR WITNESSES ATTORNEYS.

UNITED STATES :ATENT Fries.

JOHN H. HILLMAN, OF PlTTSBURG, PENNSYLVANIA, ASSIGNOR TO JAMES S. FRAZER, OF NASHVILLE, TENNESSEE.

GAS BLAST-FURNACE.

SPECIFICATION forming part of Letters Patent No. 372,912, dated November 8,1887.

Application filed May 21, 1886. Serial No. 202,872.

To all whom it may concern:

Be it known that I, JOHN H. HILLMAN, of the city of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and Improved Gas Blast-Furmice, of whichthe following is a full, clear, and exactdescription.

The object of my invention is to provide a new and improved gas blast-furnace adapted for the utilization of gases or solid fuel, or both combined, for smeltingiron or other ores.

The invention consists in the combination of a preparatory storage gasfurnace, a carburization gasfurnace, and a smelting gas blast-furnace, each separated from the others. The invention also consists of various parts and details and combinations of the same, as will be fully described hereinafter, and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a side elevation showing my improved carburizat-ion gas-furnace and smelting blast-furnace. Fig. 2 is a sectional elevation of the preparatory storage gas-furnace. Fig. 3 is a sectional plan view of the same on the line 0c 00, Fig. 2. Fig. 4 is a sectional ele vation of the carbnrizalion gasfurnace. Fig. 5 is a sectional plan view of the same on the line 1 3 Fig. 4. Fig. 6 is asectional plan view of the lower part of the carburization gasfurnace, showing a modified discharge. Fig. 7 is a sectional plan view of the same on the line 2 .2, Fig. 6.

In an ordinary blast-furnace Cleveland iron stone has been found at a red heat at a distance of twenty-one feet five inches to fifty-two feet from the top; in another furnace the same heat obtained at a distance of twenty-one feet eleven inches from the top, and in another the ore was at a very bright red at a distance of fiftytwo feet from the top, and at seventy feet from the top the ore was found to be incandescent.

' Such variations in temperature, together with the invasion of the smelting and combustion zone by raw material from the preparatory (No model.)

the furnace-man. Another difficulty experi enced by furnace-men is the superficial heating of large masses of ironstone to a high temperature while their inner portions are at a comparatively low heat. These irregularities in the action of the ordinary furnaces re sult in the production of varying qualities of iron and in the serious waste of fuel, besides the speedy destruction of the furnace-lining. By means of my improvement these difficulties are avoided by the employment of preparatory furnaces disconnected from the smelting-furnace, in which the ores are treated according to their peculiarities before being discharged into the smelting-furnace, the treatment con- '65 sisting in subjecting the ores to a greater or less heat for alonger or shorter time, and with a variable blast, all governed by the requirements of the ore under treatment.

The three main parts of my furnace are the preparatory storige gas-furnace A, (shown in Figs. 2 and 3,) the carburization gas-furnace .13, (shown in section in Figs. 4, 5, and 6, and

in elevation in the upper part of Fig. 1,) and the smelting blastfurnace 0, (shown in elevation in the lower half of Fig. 1.) The preparatory storage gasfurnace A,0f which any number required may be used in proportion to the size of the plant, is built on the ground on a suitable foundation, and so located as to re- 8:)

'ceive the iron ores and fluxes directly from the mine or railroad-cars D, which can be emptied into the chute E, leading to the inclined heating-bins F, which open into the central shaft, G, provided on its cone-shape bottom G with openings G having valves G on their outer ends and leading to the arched tunnel Gfiin which the charging-barrow G is placed. The top of the central shaft, G, is provided with the regulating-damperG". The 0 bins F are each provided on the outer side with a door, F, which is opened only for the admission of the chute E, which can be swung along on the trestleworlc D, built around the furnace A, so as to discharge the ores and fluxes into any one of the bins F desired.

Above each of the bins F is placed, in the, masonry of the furnace A,a gas-pipe, H,which zones are the occasions of serious troubles to 50 connects on the outside with the gas-pipe H, surrounding the furnace, and connected with the main pipe N for supplying the gas, which supply of gas may be from natural sourcesfrom coke-ovens-or it may be waste gas from the smelting blast-furnace or gas generated from any fuel. The pressure of the gas in the main pipe N is to be regulated according to experience. The gas-pipes H are provided with short branch tubes H", which enter the tops of the bins F, and the inner ends of the pipes H open into the central shaft, G. A supplypipe, H, is also placed in the tunnel G, and connects, by branch tubes H, passing through the cone-shape bottom G, with the central shaft,G. It will be seen that when the gas flowing from the tubes H and the branch tubes H and H is ignited, the ores and fluxes in the bins F and in the central shaft, G, are thoroughly heated by the gas-flame after the manner of a reverberatory furnace.

The admission of thegas into the furnace is regulated by valves according to the temperatnre required. The heating of the ores in preparatory furnaces prevents the cementation of the ores in case of too much heat, as often occurs in high continuous furnaces having a great superincumbent weight and mass of ore and fuel.

\Vhen the ore in'the preparatory bins F is sutiieiently prepared, it is discharged,by opening the valves G", into the barrow G, which is then rapidly moved to the elevator I, Fig. 1, and hoisted to the top of the carburization gasfurnace B,into which the ores are emptied. The preparatory storage gasfurnace, formed of the bins F and shaft G, is built of common brick and lire-brick. The central shaft, G,and the twelve bins F are preferably built circular in form to afford the strength due to thearches and to assist the reverberatory action of the gas-flame. \Vhen only the natural draft is employed, the temperature is regulated by opening or closing the door G on the top of the furnace-flue and by regulating the flow of the gas.

Each of the several preparatory gas-furnaccs can be charged with a different kind of ore, and a greater or less amount of gas-flame is used for along or short period, and a varying aiablast is applied, as the nature and density of different ores may require. The ores in each oftlie 'n'eparatory gas-furnaces are raised to a heat approaching fusion before they are discharged, as above stated.

The carburization gas-furnace B is located on top of the smelting gas blast-furnace C and rests on aheavy cast-iron plate, J, supported by columns J, mounted on a cast-iron plate, J, supported from the ground,at the base of the smelting-furnace C, by columns J. The furnace B is provided with the central shaft,K,of masonry,of sufficient size and strength to resist the impact of the ore, which is provided 011 its lower part with the cone K,and forms an annular space, B, between the outer wall,B, of the furnace B and the shaft K. In the latter is placed a strong cast-iron pipe, L, provided with branch tubes L,slanting downward and opening into the space B. The ends of the gas-pipe entering the furnaces are turned downward to prevent the clogging ofthe same.

If experience proves it necessary, the cast pipe can be supplanted by a [lue constructed of fire-brick.

The exterior of the furnace B is provided with a number of circular pipes, M, having branch tubes M, which pass through the wall B of the furnace and open into the space B. The pipes M and L are connected with the main pipe N, which leads to the supply tank or well charged with gas, and into the pipe N are also discharged the waste gases from the smelting-furnace G by means of the pipe N. The waste gas from the smelting-furnace may also beled into the circular pipe M by the connecting-pipe M".

The annularspace B of the furnace B is covered by a platform, 0, provided with doors 0 through which the ore is emptied into the annular space B from the barrow G which is moved on'the platform 0 from the elevator I, as before described. The platform O is encircled by railing 0 which supports the cone shaped top 0', carrying the smoke-stack O.

The annular space B opens at its bottom into thcdischarge P, which may be constructed as shown in Figs. 1 and 4, or as illustrated in Figs. 6 and 7. Each discharge P, as shown in Figs. 1 and 4, is provided with a hinged chute, P, through which the orcs may be passed directly into the smeltingfurnace or into barrows to be weighed before being emptied into the furnace O. I prefer, however, the construction of the discharge P,(shown in Figs. 6 and 7,) in which the discharge P opens into the funnel Q, provided with a steel cut-off valve,

Q, operated by a piston, Q, driven bysuitablc machinery.

Below the valve Q, is the measuring-compartment R, provided on its bottom with the downwardly-opening doors It, and provided on one side with the exhaust-fan It, which sucks up detrimental snbstances,such as ashes, &c., contained in the charge, and forces the same out through the spout R. The charge ofores in the compartment is easily calculated, as the cubical contents of the compartment 1% is known. The doors are kept closed until the compartmentistilled. Thenthcvalveispushed inward to divide the compartment Rfrom the funnel Q, after which the doors are opened and the ore emptied into the smelting-furnace.

The smelting-furnace C may be constructed with an elliptical or round cross section. \Vhen built elliptical, it admits of the use of more tuyeres, and its cubical contents are greater without great hcight, the latter not being needed in the smelting-furnace, as the ores are well prepared before entering this furnace, so that it is possible to secure maximum results in reducing ores to a metallic condition with a small amount of fuel. A strong air-blast is introduced into the smelting-fursible, in the manner above described.

nace in the usual manner, and the preparatory furnaces are furnished with a weak or strong blast according to the character of the fuel and the requirements of the ore being treated.

At the top of the furnace O ores are introduced'from the earburization-furnace B at a high heat, approaching fusion as nearly as pos- The regular fuelcoke, coal, or charcoal is also introduced at the top in the usual manner, and from the barrow U soft ores,not needing longcontinued treatment in the preparatory-furnace and in the carburization-furnace, are also introduced and mixed with the more refractory-ores from the furnaces A and B.

The final completion of carbon absorption, oxidation, &c., occurs in this furnace O, and, owing to the thoroughpreparation of the ores before entering this furnace, the necessary condition for smelting is quickly obtained after the ores have entered the furnace,and they are rapidly reduced by the aid of the strong blast without the .usual risks of raw ores coming into this furnace. No hydrocarbon or other gases are introduced into this furnace, which is only charged with the coal, coke, or charcoal. The waste gases from this furnace are carried away from the top by means of the pipes N and M and are utilized in the carburization-furnace B, as before described, or in the heating of hot-blast stoves and the generation of steam as needed. The solid fuel used in the blast-furnace C may be raised to an incandescent state in either the preparatory gas furnace A or the carburization'furnace B before entering the blast-furnace 0, thereby insuring that no hydrocarbon will enter the blast-furnace as the fuel. Hence, with the ores in an incandescent state no trouble arises from using too much blast, and no interruption in the final smelting operation takes place.

In the furnaces A and B the ores are raised to a temperature of about 1,200 centigrade by the use of the gas as a heating medium. so

that the ores approach nearlyto fusion before going into the smelting-furnace O. In the latter furnace I can then use weak coke, charcoal, or dry splint coal as the heating medium, and thus obtain better results than by using a tall connected shaft-furnace; but good coke is just as efficacious in this furnace system as in any other blast-furnace.

To conserve the heat to the fullest extent I place between the jacket of the furnaces and the lining a septum, of asbestus or similar material,which confines the heat and secures uniformity in the operation of the furnaces, at the same time securing economy of fuel.

\Vith this system, having absolute control of the amount of heat absorption and the'necessary length of time needed for thorough saturation and carbon impregnation of ores and fluxes, I can obtain any grade of iron de sired, even in districts where coke is weak'and a large percentage of ash has to be contended With. Withmy furnace I am enabled to use dry splintcoal, noncoking, which cannot be used in taller connected zone-furnaces because of theimpact due to its decrepitation. These coals have the necessary carbon and freedom from sulphur; but as their mechanical construction is such that they decrepitate, they cannot be used in tall furnaces, but can be used in my improved system of furnaces.

The time used in the preparation and the amount of heat vary with the ores treated, as some ores require more and alonger continued heat than others.

The uniform work obtained by my furnace obviates the necessity of frequent relining of the interior of the furnace, which is made necessary by the irregular work done in other furnaces and the consequent destruction of the walls.

I am enabled to utilize impure fuel, in giving a large part of the heat needed,aud after ward complete the smelting operation in the blast-furnace G with charcoalor good coke, and thereby obtain a larger amount of iron free from metalloids than by any other system, and,'as cold blast can vbe used without much risk, I obtain strong and low silicon iron with a small amount of fuel, a result which cannot be secured by the taller continuous shaft-furnaces.

Many refractory ores can be treated successfully and used after the preparation given in this furnace which would otherwise be rejected.

Careful practical and chemical examinations can be made as the ores pass from the preparatory furnace A and the carburization gas furnace B into the smelting blast-furnace O. The gases can be sufficiently expanded before combustion takes place in the furnaces A and B, and the atmospheric air used in either fur-- nace can be preheated before entering the furnace or not. This expansion of atmospheric air, however, is advisable only when soft iron is to be made. I

The blast from the blowing engine which goes into the smelting-furnaces 0 may also be heated or not, in the usual manner, according to the grades of the iron to be manufactured. This system can be added as an improvement to many existing furnaces.

My improved gas blast-furnace utilizes gas from coke-ovens, the waste gases from the smelting-furnace, natural gas, gas from coal or other fuel, and also permits of the use of dry splint or non-coking coal, coke, or charcoal in the carburization-furnace. It permits of the treatment of different kinds of ores separately, according to their requirements. It avoids the great pressure of high columns of material and permits of the free upward passage 'of the gases. My construction also admitsof the use of a greater number of tuyeres and more blast than ordinary furnaces, thereby securing a greater output of iron with a smaller amount of fuel.

IIO

In my improved furnace the ores and fluxes are prepared in well-defined zones, so that the entire process of smelting may be conducted with great regularity and with certainty as to the quality of the product. The gases generated in the lower zones are utilized in the upper zones, so that the fuel is utilized to the fullest possible extent.

In my system of furnaces hematite, calcareous, carboniferous, specular, and bog ores can be treated. In fact, any ores employed in making iron, which are treated with more or less heatand blast, as their nature demands, can be treated therein. The lime used for fluxing is also treated and raised to a high heat with the blast and reverberatory fiame, such as the iron ores require. The limestone for fluxiug is kept in separate preparatory furnaces from those containing ore. \Vhen the ore and limestone flux are raised to about 1,200 centigrade, they are then properly mixed in the proportions required by the kind of ore used, the amount of limestone used to flux ores varying from ten to fifty per cent. of the ore charged. The amount of limestone used as flux is generally regulated by the percentage of silica and other melalloids contained in the ore. \Vhcn thus mixed, they are trans ferred rapidly,by means of hoisting machinery and charging buggies, into the carburizationfurnace. In this furnace a blast of somewhat increased pressure to that used in the preparatory gasfuruacc is used. This blast is applied directly to the second or carburization furnance or zone. This is done in no other furnace system and of course in no mere calcining kiln or furnace not having this construction. The prepared ore and flux lime stone having been raised to a heat approaching fusion, (such a heat as cannot be obtained in ordinary calcining-kilns without blast,)are taken from the earlnirization furnace and dropped into the measuririg-compartments Q and It, and from thence dropped, through the door B, into the blast-furnace O in an incandescentstate. The solid fueleoke, charcoal, or coal-having been raised to a high heat, is also charged in proper proportion into the blast-furnace O, by means of chargingbarrows V,in the ordinary wayin which fuel is charged into a furnace. It will be noticed that the detritus accumulating in the carburizationfurnace is exhausted by the fan-blast. The blastfurnace is blown with a very strong blast.

My invention, as relates to the preparatory storage gas-furnace, differs from, and is an improvement over, the corresponding zone in connected shaft-furnaces in that the heat-flame is gaseous and the form of this furnace is such that the rcverbcratory effect of the heat is so cured, and hence a more intense heat is obtained than is secured in the corresponding zone of an ordinary furnace or any more cal cining kiln. It is a blast-furnace, and also has the revcrberatory action of the flame, thus differing from the Siemens and Stine or any other more calcining kiln or furnace, as exemplified by the other furnaces using merely the natural draft and having no reverberatory flame, as is secured by using the central shaft of the preparatory storage gas-furnace, combined with the blast, to rcverberate the heat into the side storage-bins containing the ores. It is also essentially different from these furnaces in that it prevents the cementation of the ores which are contained in the side bins.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination, in a preparatory storage gas-furnace, of a central shaft, G, and the inclined bins F, opening into the central shaft, G, the gas-pipes H and H, and the branch tubes H and H, substantially as shown and described.

2. The combination, in a preparatory storage gas-furnace, of a central shaft, G, having a cone-shaped bottom, G, provided with outlets G" and valves G, and the inclined bins F, opening into the central shaft G, and provided with door F, with the gas-pipes H and H, and the branch tubes H and H, substantially as shown and described.

3. The combination, in a earburizatlon gafurnace, of the side wall, B", and the shaft K, forming an annular space, B, with the gaspipes L and M. and the branch tubes L and M, the tubes L connecting the pipes L with the furnace-chamber at intervals throughout its height, and the tubes M similarly connecting the pipes M with the said chamber, substantially as shown and described.

4. The combination, in acarburization gasfurnace, of the side wall, B and the shaft K, provided with the cone K, and forming an annular space, B, between the outer walls and the shaft K, with the gas-pipes L and M, and the branch tubes L and M, the tubes L conmeeting the pipes L with the furnacechamher at intervals throughout its height, and the tubes M similarly connecting thepipes M with the said chamber, substantially as shown and described. 5. The combination, in a carburization gasfurnacc, of side wall, 13*, and a shaft, K, forming an annular space, B, the outlet P, and the doors 0 in the platform 0, with the gas-pipes L and M, and the branch tubes M and L, substantially as shown and described.

6. The combination of a carbnrization gasfurnace, B, provided with a discharge, P,with a funnel, Q, a cut-off, Q, and a measuringchamber, R, provided wit-h the doors R, substantially as shown and described.

7. The combination of a carburization gasfurnace provided with the discharge P, with a funnel, Q, a cutoff, Q, and a measuringchamber, R, provided with the doors R, and the fan R substantially as shown and described.

8. In a plant for reducing ores, the combination, with the furnace A, blast-furnace C, and the carburizing-furnace B, of the gas-pipes M, N, L, and H, connecting with furnace B, and the branch tubes N, M, M L, and H,

the tubes N and M connecting with the furnace O and with the pipes N and M, respectively, the tubes M and L connecting with the furnace B and With the pipes M and L, respectively, the pipes H and tubes H connecting with the furnace A, and the tubes H connecting with the pipes H, substantially as shown and described. 7 l

9. The process of producing pig-iron from mixed ores of different grades, which consists in simultaneously roasting the ores at different temperatures and then discharging the ores in a highly-heated state into a carburizing-furnace, subjecting the mixed and roasted ores to a carburizing-flame, and finally smelting the charge in a blast-furnace, substantially as specified.

10. The process of preparing different grades of ores for smelting,.which consists in simultaheously subjecting the said ores to a carbu- 2o rizing-flame and to variable blasts, according to the qualities of the ores, bringing the several grades to thesame condition at the same time, substantially as specified.

11. The method of producing pig-iron,which 2 5 consists in heating the different ores and fluxes in different bins with different degrees of heat and differing force of blast, then discharging the ores and the fluxes into the carburizationfurnace, carburizing them by means of coal- 30 gas or natural gas and air-blast, then discharging them in a state of incandescence into the smelting-furnace, and finally smelting them under a strong blast.

JOHN H. HILLMAN.

\rVitnesses:

DAVID P. BLACK, J. L. GLONINGER.

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