US2052928A - Blast furnace hearth and bosh - Google Patents

Description

sept- 1935' G. M. HARRIS 2,052,928

BLAST FURNACE HEARTH AND BOSI-i Filed Dec. 20, 1955 3 Sheets-Sheet 1 'INVENTOR.

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ATTORNEYS p 1935- G. M. HARRIS I 2,052,928

BLAST FURNACE HEARTH AND BOSH F 'iled Dec. 20, 1935 5 Sheets-Sheet 2 INVENT OR.

ATTORNEYfi v Sept. 1, 1936.

G. M. HARRIS s Sheets-Sheet 3 Filed Dec. 20, 1935 INVENTOR. GPIRNErrMfiR/P/a ATTORNEY5 Patented Sept. 1, 1936.

UNHTED STATES PATENT OFFICE Garnett M. Harris, Birmingham, Ala. Application December 20, 1935, Serial No. 55,480

' 15 Claims.

This invention relates in general to blast furnaces of the character used for the smelting of ores such-as iron ore and the like and more particularly to those parts of the furnace known as the crucible and the bosh.

The conventional blast furnaces of the modern type in general use for smelting iron ore usually comprise .a refractory lined structure approximately ninety feet in height and about twentyfive feet Outside diameter. Such furnaces usually comprise elements corresponding to hollow cylinders and hollow truncated cones superposed on each other. The bottommost section of the furnace is usually referred to either as the hearth or the crucible and in common practice it is usually about eighteen feet in diameter and about twelve feet high. Liquid iron and slag collect in this crucible portion and are withdrawn at regular intervals through the iron and cinder notches located near the bottom and top of the crucible.

Above the crucible portion, there is usually-aw portion corresponding to a hollow truncated cone whose walls diverge upwardly, known as the bosh. Above the bosh, there is a long section known as the stack, resembling a hollow truncated cone whose walls converge upwardly. At the top of the stack, suitable charging bells and platforms are ordinarily provided.

The stack of the furnace is usually insulated with a layer of firebrick approximately four feet thick, while the bosh and crucible portions are considerably thinner. However, they customarily have refractory linings which are water cooled by incorporating in the structure hollow copper blocks through which .water is continuously circulated.

Near the top of the crucible or hearth, there is a circumferential series of tuyres through which air is forced under pressure from an annular pipe surrounding the furnace, commonly known as a bustle-pipe. The several .tuyeres are suitably connected with the bustle-pipe and the connections are customarily so arranged that as 45 the tuyeres burn out they can be readilywithdrawn and new ones inserted.

In all iron blast furnaces or other ore smelting furnaces of which I have knowledge, the air blast is directed inwardly from the exterior. of the fur- 50 nace toward the central portion thereof.

My invention contemplates a radical departure from the design and arrangement of blast furnaces now in general use in that instead'of discharging the blast air only from the outer por- 55 tion of the furnace inward, I provide means whereby a separate series of tuyeres are operative to discharge blasts of air from the central zone of the furnace outwardly. This is considered to be highly desirable in order to cause the blast to penetrate practically the entire cross sectional area of the crucible. This will result in a more 5 even burning of the coke charged to the furnace and a more even or gentle settlement of the stock and a better distribution of the gases as they rise through the stack of the furnace above the tuyere level. And the whole operation of the 10 furnace would be improved and its efiiciency considerably increased.

In the old furnaces of the prior art hereinabove briefly described, the air blast performs three major functions, one, preheating the ore, coke l5 and limestone, deoxidizing the metallic oxides of the'ore and converting the resulting iron and slag to a molten state. The raw charging materials, such as iron ore, coke and flux such as limestone, are charged into the top of the furnace and descend countercurrent to the great volumes of carbon monoxide and nitrogen generated near the lower part of the furnace.

As the charging materials descend countercurrent to the rising reducing gases, the more 25 easily reduced high oxides come in contact with the gas of the lowest reducing power, and the gas richest in carbon monoxide reacts with the ore in the final stages of reduction at the lower levels of the furnace. This well known phe- 30 nomena results in an excellent utilization of the reduciiig power of the gases. and is in a measure largelyresponsible for the almost universal utilization of the conventional type of iron smelting blast furnace above briefly referred to. 35

It is fairly well recognized that the seat of life of a blast furnace is in the neighborhood of the combustion zones in front of the tuyeres because the heat as well as the reducing gases for carrying on the process are generated in this part 4 of the furnace. But, in the types of furnaces heretofore generally used, there is an inactive zone, by which I mean, there is a zone wherein. combustion is not taking place throughout the entire cross sectional area of the furnace at the tuyere zone. Studies and investigations establish the fact that combustion zones are about the same area for a small furnace as for a largeone. Thus, in conventional furnaces, there is an inactive zone at the tuyere level of the furnace. With a furnace having a crucible diameter of twenty-five feet, this inactive area represents a large fraction of the total area. But, in spite of this crucible condition in this art crucible areas have been increased until the furnace of the type used ten years ago, which would produce about six hundred tons of iron per day, now produces about one thousand tons per day. Such large furnaces have operated smoothly and efliciently.

But, the gain in the furnace production has not been in proportion to the increase in crucible area and there has been little or no real improvement in the efllciency of the furnace as measured by fuel consumption.

In the furnace embodying my invention, the crucible is materially increased in diameter. But, its area may be decreased or increased because I so arrange the structure of the furnace that an annular crucible is provided and. I arrange the tuyeres in such a way that one series of tuyeres directs the air blast inwardly and another set'of tuyeres directs the blast outwardly and I arrange the tuyeres in the different sets or series in a staggered relationship so that the 'zone of influence of the blast from the tuyeres is felt virtually throughout the entire sectional area of the hearth or crucible. This comprises a blast furnace structure having an annular crucible and an annular bosh-and with provision for a tuyere room in the center of the furnace where workmen can enter for the purpose of changing tuyeres or observing the action of the furnace through suitable peep-holes in the tuyeres. The top of this tuyere room, to withstand the heat, is provided with a water cooled dome and the innerbosh wall is water cooled. And fresh air is supplied to the tuyere room, so as to maintain theatmosphere in such condition that the workmen can perform their necessary duties in this location, which it will be remembered is surrounded by molten iron, iron ore, flux and other stock materials in the annular bosh of the furnace.

A furnace embodying the above described and other features of my invention is illustrated in the accompanying drawings, in which- Fig. 1 is a vertical longitudinal section through the improved furnace, the stack portion having been foreshortened, however, to enable showing of the bosh and crucible portions on a legible scale; Fig. 2 is a cross section of the crucible and bosh portions of the furnace, at a scale much greater than that of Fig. 1; Fig. 3 is a horizontal section taken through the furnace at the tuyere level. v

With reference to the detailed features of the structure illustrated, lll represents a suitable foundation portion which supports the concentric annular outer and inner wall portions l I and I2, respectively, of the crucible portion of the furnace. Above the crucible, there are outer and inner annular bosh walls I3 and t4, the outer bosh wall diverging upwardly and outwardly and the inner bosh wall converging inwardly and upwardly. Above the bosh wall, the furnace is substantially of conventional construction and includes the usual stack wall 16 and the usual outer shell l'l. At the stock line, I provide a conventional form of stock line armor I81. And

blast air delivered to the outer circumferential series of tuyeres 2|. These tuyeres are of conventional type and are positioned in a. conventional manner in water cooled tuyere coolers, indicated at 2|. All of the tuyeres of the seshown or described in detail.

outer walls II and I3 of the crucible and bosh, re-

ries indicated by the numerals 2| direct the blast inwardly into the annular hearth or crucible 22.

An inner series of tuyeres 23 are positioned in suitable tuyere coolers 24 and they each direct an air blast into the crucible in a direction extending radially outward from the center of the furnace. The tuyeres 23, as viewed in plan, are arranged in staggered relation to the tuyeres 2| of the outer series. It is thus clear that in such an arrangement the blast coming from two di-.

rections will penetrate practically the entire cross section of the crucible and the combined com-- bustion zones will practically cover this area, hence all inactive spaces will be eliminated. This will result in a more even burning of the coke, a more uniform settlement of the stock anda better distribution of the reducing gases as they arise through the stock above the tuyere level.

For supplying the blast air to the inner set of 20 tuyeres 23, I provide a blast main 25 which communicates with a suitable supply of hot blast air. At its upper end, the pipe has a plurality of lateral branches which communicate by means of fittings 26 with adjacent pairs of tuyeres 2: as 2:

fully apparent from Figs. 2 and 3. This pipe enters through a tunnel 21 formed in the foundation ill of the furnace, which tunnel also serves as means of access and egress for the workmen, who

must enter the central tuyere room 28. This 36 is lined on the interior with a hollow metal shell 34 conforming in shape to the dome. This jacket is supported by a metal lining indicated at 35. This lining is of stepped formation and is provided with a plurality of inward extensions 36 which are water cooled. These resemble the conventional forms of insert members, indicated at 31, which extend inwardly into the outer bosh wail l3, so as to prolong the life of the bosh wall.

A water supply pipe 38 enters through the tunnel 21 and extends upwardly through the shaft 23 and into the central tuyere room and connects in a suitable manner with the water jacketed shell 34 and with the inserts 36 in any suitable manner by the use of any conventional form of pipe fittings and connections which need not be r Fresh cooled air is supplied to the tuyere room 23 by pipe 39, so as to maintain livable working conditions in this room, which must be occupied by blast furnace attendants, in order to permit inspection of the tuyeres and the removal and re- 00 newal of the same when necessary. The furnace is provided with the usual iro notch 40 through which the molten iron is periodically withdrawn and also a typical form of cinder notch 4|, through which a slag is discharged each time the furnace is tapped.

The exterior of the furnace is formed with the usual mantle 42 which is carried by pillars 43 spectively.

While I have described quite precisely the design and arrangement of the furnace herein illustrated, it is to be understoodthat the drawings and description are to be interpreted in an illustrative rather than a limiting sense since various modifications may be made by those skilled in the art without departure from the invention as defined in theappended claims.

What I claim is:

l. A blast furnace for smelting ores comprising inner and outer walls defining an annular crucible, an annular bosh thereabove, a stack above the bosh and crucible, an outer series of tuyeres extending through the outer wall of said crucible and an inner series of tuyres extending through the inner wall of said crucible.

2. A blast furnace for smelting ores comprising a pair of upright walls defining an annular crucible, a pair of bosh walls thereabove defining an annular bosh, a stack wall rising from the bosh wall, and respective sets of tuyeres fordirecting air blasts into the annular crucible in respectively inward and outward directions.

3. A blast furnace of the character described comprising a pair of substantially concentric crucible walls defining an annular hearth, an upwardly and outwardly diverging bosh wall rising from the outer wall of the crucible and an inwardly and upwardly converging bosh wall rising from the inner wall of the crucible, an outer series of tuyeres for directing air blasts inwardly into the crucible, andan inner series of tuyeres for directing air blasts outwardly into the crucible.

4. A blast furnace of the character described comprising inner and outer crucible walls defining an annular hearth, an. outer annular bosh wall diverging outwardly and upwardly from the upper portion of the outer crucible wall, an inner annular bosh wall rising from the inner wall of th crucible and having a dome-like roof defining a tuyere chamber, an outer set of tuyeres for directing an air blast inwardly into the crucible, an inner set of tuyeres located in said tuyre chamber for directing air blasts outwardly into the crucible.

5. A blast furnace of the character described comprising inner and outer crucible walls defining an annular crucible, an outer annular bosh wall diverging outwardly andupwardly from the upper portion of the outer crucible wall, an inner annular bosh wall rising from the inner walls of the crucible and having a dome-like roof defining a tuyre chamber, an outer set of tuyres for directing an air blast inwardly into the crucible, an inner set of tuyres located in the tuyere chamber for directing air blasts outwardly into the crucible, a foundation for the crucible having a tunnel anda shaftway therein to permit the passage of workmen to and from the tuyre chamber. e

6. A blast furnace of the character described comprising inner and outer crucible walls definfor the crucible having a tunnel and a ehartwav therein to permit the passage of workmen to and from the tuyere chamber.

7. A blast furnace of the character described comprising inner and outer crucible walls defining an annular hearth, an outer annular bosh wall diverging outwardly and upwardly from the upper portion of the outer crucible wall, an inner annular bosh wall rising from the inner wall of the crucible and having a dome-like roof defining a-tuyre chamber, an outer set of tuyres for directing an air blast inwardly into the crucible, an inner set of tuyeres located in the tuyre chamber for directing air blasts outwardly into the crucible, a foundation for the crucible having a tunnel and a shaftway therein to permit the passage of workmen to and from the tuyere chamber, and a water cooled lining for said shaftway.

8. A blast furnace of the character described comprising inner and outer crucible walls defining an annular hearth, an outer annular bosh wall diverging outwardly and upwardly from'the upper portion of the outer crucible wall, an inner annular bosh wall rising from the inner wall of the crucible and having a dome-like roof defining a tuyre chamber, an outer set of tuyeres for directing an air blast inwardly into the crucible, an inner set of tuyres located in the tuyere chamber for directing air blasts outwardly into the crucible, a foundation for the crucible having a tunnel and a shaftway therein to permit the passage of workmen to and from the tuyere chamber, and an air blast pipe extending through said shaftway and having a plurality of branches communicating with the inner series of tuyeres.

9. A blast furnace of the character described comprising inner and outer crucible walls defining an annular hearth; an outer annular bosh wall diverging outwardly and upwardly from the upper portion of the outer crucible wall, an inner annular bosh wall rising from the inner wall of the crucible and having a dome-like roof defining a tuyre chamber, an outer set of tuyres for directing an air blast inwardly into the crucible, an inner set of tuyeres located in the tuyre chamber for directing air blasts outwardly into the crucible, a foundation for the crucible having atunnel and a shaftway therein to permit the passage of workmen to and from the tuyere chamher, and a pipe opening into said tuyere room for supplying fresh air thereto.

10. A blast furnace of the character described comprising a foundation having inner and outer substantially concentric crucible walls defining an annular crucible, an outer bosh wall rising from the crucible wall, an inner upwardly and inwardly converging bosh wall rising from the inner crucible wall and having a dome-like roof defining a. tuyre chamber, a water cooled metallic lining for said chamber, an outer set of tuyres communicating with a bustle-pipe for supplying blast air to said outer series of tuyres, an inner series of tuyres located in said tuyre chamber and an air blast pipe having a plurality of branches com- 'municating with said inner set of tuyeres, a

tunnel below the crucible and a shaftway communicating with said tunnel and said tuyere chamber so as to permit passage of workmen to and from said chamber.

11. A blast furnace of the character described having inner and outer wall portions defining an annular crucible and an inner shaftway, inner and outer bosh walls rising respectively from the inner and outer wall portions, a stack supported by pillars carried by the foundation and rising above the outer bosh wall, an outer set of tuyeres for directing air blasts inwardly into the annular crucible. an inner set of tuyres for directing air blasts outwardly into the annular crucible, a roof which with the inner bosh wall defines a tuyere chamber, a flooring for the accommodation of workmen'in said chamber and an air blast supply pipe for the inner set of tuyres extending into said tuyere chamber.'

12. A blast furnace of the character described having inner and outer wall portions defining an annular crucible and an inner shaftway, inner and.outer bosh walls rising respectively from said inner and outer wall portions, a stack supported by pillars carried by the foundation and rising tending into said tuyere chamber, means for water cooling the roof of said tuyere chamber and means for discharging fresh air into said chamher so as to maintain a livable atmosphere therein.

13. A blast furnace for smelting ores comprising inner and outer wall portions defining an annular crucible and-an annular bosh, a stack 5 above the bosh and inner and outer sets of tuyeres efiective to distribute air blasts over substantially the entire sectional area of the crucible.

14. A blast furnace for smelting ores comprising inner and outer wall portions defining an annular crucible and an annular bosh, a stack portion above the bosh. and vtuyeres eflective todistribute an air blast throughout substantially the entire cross sectional area of said annular cru cible.

15. A blast furnace for smelting ores comprising inner and outer wall portions defining'an annular crucible,-an innerstructure which in con- Junction with theinner wall of the crucible de-.

fines an inner tuyere chamber, an outer annular 20 wall rising from the outer wall of the crucible, an inner set of tuyeres in said chamber effective to direct air blasts outwardly into the crucible and an outer set of tuyeres effective to direct air blasts inwardly into the crucible. 25

GARNE'I'I M. HARRIS.

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