US3623717A

US3623717A - Self-supporting blast furnace shell and metallic lining for blast furnace

Info

Publication number: US3623717A
Application number: US750968A
Authority: US
Inventors: Lawrence G Maloney; William E Slagnley
Original assignee: Inland Steel Co
Current assignee: Inland Steel Co
Priority date: 1968-08-07
Filing date: 1968-08-07
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30
Also published as: CA954298A

Abstract

A one-piece, integral blast furnace shell, the totality of which is self-supporting and which extends continuously, without interruption from the top of the stack to the bottom of the hearth. No mantle; no columns. A fluid-cooled internal metallic lining for a blast furnace. The lining extends continuously, without interruption, and without sharp angular changes, from the top of the stack to the lower part of the bosh. The lining is movably mounted to accommodate thermal changes in furnace.

Description

United States Patent Inventors Lawrence G. Maloney Munster; William EJSlagnley, Crown Point, both oi Ind. Appl. No. 750,968 Filed Aug. 7, 1968 Patented Nov. 30, 1971 Assignee Inland Steel Company Chicago, Ill.

SELF-SUPPORTING BLAST FURNACE SHELL AND METALLIC LINING FOR BLAST FURNACE 12 Claims, 14 Drawing Figs.

US. Cl 266/25, 266/32 Int. Cl C2lb 7/00 Field of Search 266/25. 32.

43, 27, 29,31, 17; 263/29; 1 l0/l A [56] References Cited UNITED STATES PATENTS 1,792,614 2/1931 Stern 266/25 X 2,339,192 1/1944 Roberson 266/25 2,770,451 11/1956 Almond 263/29 3.371918 3/1968 Ueshima et a1.. 266/43 3,431,691 3/1969 Greaves et a1. 266/25 X FOREIGN PATENTS 471 ,973 9/1937 Great Britain 1 10/1 A Primary EkamineF-Gerald A. Dost Attorney-Merriam. Marshall, Shapiro & Klose ABSTRACT: A one-piece, integral blast furnace shell the totality of which is self-supporting and which extends continuously, without interruption from the top of the stack to the bottom of the hearth. No mantle; no columns.

A fluid-cooled internal metallic lining for a blast furnace. The lining extends continuously, without interruption. and without sharp angular changes, from the top of the stack to the lower part of the bosh. The lining is movably mounted to accommodate thermal changes in furnace.

SELF-SUPPORTING BLAST FURNACE SHELL AND METALLIC LINING FOR BLAST FURNACE BACKGROUND OF THE INVENTION Conventional blast furnaces have a steel outer shell and an inner refractory lining. The furnace and the shell comprise, in vertically descending sequence, a stack section, a bosh section and a hearth section. Tuyeres, located around the periphery of the furnace, extend into the furnace interior at the top of the hearth section to provide combustion gases such as air to the furnace interior. A superstructure, including apparatus for introducing charging material into and exhausting gases from the top of the blast furnace, is generally located above and supported atop the stack section of the shell.

The stack section has by far the largest vertical dimension of any of the shell sections, and, conventionally, the stack section is supported independently of the lower bosh and hearth sections by a ringlike mantle offset from the lower shell sections and underlying the stack section and its refractory lining. The mantle is located at the junction of the stack and bosh sections, although, conventionally, these two sections are not jointed. The mantle is supported by a plurality of columns resting on a relatively massive foundation extending downwardly from the floor of the furnace cast house or from grade.

The conventional blast furnace shell and supporting structure have a number of drawbacks. For example, the mantle is a thick, cumbersome structure which introduces special stress, cooling and refractory problems at the junction of the stack and bosh sections and which requires special expansion joints at this junction.

The presence of the mantel-supporting columns restricts the furnace design in such design areas as the number and spacing of tuyeres, the location of cinder and iron notches in the furnace, the arrangement of runners leading from the furnace for carrying away slag and molten iron, and the location of various auxiliary equipment. Because of the columns, the tuyeres cannot generally be located symmetrically around the furnace. Moreover, the columns reduce the working space and cause congestion around the lower part of the furnace; the columns limit access to portions of the hearth section and bosh section of the furnace; and the columns greatly limit the use of mechanized equipment around the bottom of the furnace, an area where mechanized equipment is greatly needed.

Referring now to the interior of the blast furnace, for many years the interior was lined with refractory brick in the stack and bosh sections of the furnace. This refractory lining was either entirely uncooled or was cooled with conventional copper cooling plates which extended inwardly through openings in the furnace shell and which were embedded at spaced intervals in the refractory lining. The furnace shell openings for the copper cooling plates were weak spots from the standpoint of maintaining a gastight vessel.

More recently, the interior of the furnace, in the stack section thereof, has been lined with vertically stacked tiers of circumferentially arranged metallic cooling staves cooled by circulating a cooling fluid therethrough. The staves are mounted on the furnace shell inwardly of the shell and refractory material is located inwardly of the cooling staves. The cooling staves minimize the erosion of the refractory material; and, in cases where refractory material has been completely worn away, the cooling staves cause tacky slag or charging material to fuse to the inner surface of the staves and provide, in effect, a replacement refractory lining on the inside of the cooling stave.

Fluid-cooled metallic linings, composed of staves, for the stack section of a blast furnace are shown in Rosenak U.S. Pat. No. 3,314,668 and in Zherebin et al. U.S. Pat. No. 3,379,427.

The interior furnace lines of conventional blast furnaces, including those with metallic cooling staves, comprise sharp angular changes at the junction of the stack section and bosh section and again at the junction of the bosh section and hearth section. These sharp angular changes at the interior LII surface of the blast furnace wall cause sudden changes of direction in the blast furnace charge material as it descends from the top to the bottom of the furnace, and this is not desirable because it increases wear on the furnace interior walls and causes serious changes in the interior furnace lines.

SUMMARY OF THE lNVENTlON All of the above described defects in conventional blast furnace shells and in conventional blast furnace linings are eliminated with embodiments in accordance with the present invention.

A blast furnace shell in accordance with the present invention is entirely self-supporting, eliminating the mantle, the mantle-supporting columns, the expansion joint at the junction of the stack and bosh sections, and the massive foundations for supporting the columns. Undesirable stress concentrations, previously inherent in conventional furnaces in the area about the junction of the nonintegral stack and bosh sections, are also eliminated.

The additional space created around the outside of the furnace bottom by the elimination of columns permits utilization of mechanized equipment heretofore not possible and provides greater flexibility in furnace design and in placement of auxiliary equipment on the outside of the furnace bottom.

The shell has an integral, one-piece construction extending continuously, without interruption from the top of the stack section to the bottom of the hearth section. This type of construction is especially adaptable to external spray-type cooling, pennitting the spray to trickle continuously from the top to the bottom of the furnace around the periphery of the furnace shell.

in one embodiment, the furnace is provided with stiffening rings, around the shell exterior, attached to permit the shell to expand and contract, due to thermal variations during operation of the furnace, without permanently distorting the furnace.

Because the furnace is of one-piece construction, gas leakage is reduced and the ventilation requirements of the furnace house are correspondingly reduced.

Blast furnaces are being operated at higher and higher pressures, and the one-piece, integral construction withstands such higher pressures better than do conventional furnaces provided, for example, with expansion joints which are weak spots in withstanding leakage at high pressures.

The self-supporting shell may be lined with a conventional refractory lining without interior cooling, or it may utilize conventional copper cooling plates for cooling the interior lining, or it may use metallic cooling staves between the shell and the refractory lining with the cooling staves being constructed as previously proposed by others or as disclosed herein in accordance with another embodiment of this invention.

The problems inherent in conventional interior linings and internal cooling devices for blast furnace are eliminated in accordance with additional embodiments of the present invention.

More specifically, the present invention embodies a metallic lining for the furnace interior which extends continuously, without interruption from the top of the stack section to the lower part of the bosh section and which eliminates all sudden angular changes in the interior surface of the furnace wall. The metallic cooling staves forming the internal metallic lining are mounted, with bolts extending through the furnace shell, for movement relative to the shell to accommodate radially directed forces in the furnace interior. Effective gas seals are provided for both the stave-mounting bolts and for cooling fluid conduits which extend from the staves through the furnace shell. The interior furnace lines are permanent. Conventional, erodable brick lining is eliminated in both the stack and bosh sections of the furnace. The metallic cooling staves are installed at the desired working lines of the furnace, and these lines do not significantly change.

The result is an internally cooled, gastight blast furnace having permanent interior lines defining a maximum internal volume and having a metallic lining defining a vertically disposed internal space with gradually changing lateral dimensions along the entire vertical dimension of the lining.

Other features and advantages are inherent in the structures claimed and disclosed or will become apparent to those skilled in the art from the following diagrammatic drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary vertical sectional view showing a blast furnace having a shell constructed in accordance with an embodiment of the present invention;

FIG. 2 is an enlarged fragmentary sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary sectional view illustrating lower sections of the shell;

FIGS. 4, 5 and 6 are diagrammatic illustrations of the contours of blast furnaces having self-supporting shells constructed in accordance with embodiments of the present invention;

FIGS. 7 and 8 are fragmentary sectional views illustrating a portion of the wall of a blast furnace having a shell con structed in accordance with an embodiment of the present invention, each showing a different type of structure for supporting a refractory lining in the stack section of the furnace;

FIG. 9 is a vertical sectional view of the upper part of a blast furnace having a metallic lining in accordance with an embodiment of the present invention;

FIG. 10 is a vertical sectional view of the lower portion of the blast furnace of FIG. 9;

FIG. 11 is an enlarged fragmentary sectional view illustrating the attachment to the shell of the blast furnace of a metallic cooling stave and a cooling fluid conduit for the stave;

FIG. 12 is a view from the furnace interior of a metallic lining for the bosh section of the blast furnace;

FIG. 13 is a view from the furnace interior of a metallic lining for the stack section of the blast furnace; and

FIG. 14 is a fragmentary vertical sectional view illustrating stiffening rings for a self-supporting blast furnace shell in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring initially to FIG. 1, there is shown a blast furnace having a metallic shell, indicated generally at 10, composed of welded steel plates and constructed in accordance with an embodiment of the present invention. Located inwardly of shell 10 is a refractory lining 11 cooled by metallic cooling staves 17 located between shell 10 and refractory lining 11.

At the top of shell 10 is an opening 12 through which charging material is introduced into the furnace. Seated in opening 12 is a conventional charging bell 13 movable vertically for opening or closing opening 12. Located around the interior of the furnace, just below opening 12, are metallic wear plates 14 for absorbing the impact and abrasion of charging material introduced into the furnace through opening 12. Wear plates 14 may be constructed in accordance with structures disclosed in Slagley U.S. Pat. No. 3,202,407 or as subsequently described herein. Located just below wear plates 14 are tiers of additional plates 15 constituting a stockline armor which absorbs the impact and abrasion of charging material descending from the top of the furnace. The stockline armor may be constructed in accordance with structures disclosed in Maloney U.S. Pat. No. 3,404,876.

Also located at the top of the furnace is an exhaust conduit 16 for exhausting gases from the top of the furnace.

Furnace shell 10 includes, in vertically descending sequence, a stack section 20, bosh section 21 and a hearth section 22, all joined together to form an integral, continuous,

uninterrupted, one-piece blast furnace shell composed of the three

shell sections

20, 21, 22. Shell 10 is entirely self-supporting with the sole support for stack section 20 consisting of

shell sections

21, 22 located below the stack section. Each of the

lower shell sections

21, 22 has sufficient strength to support the shell sections located thereabove and this strength is maintained during operation of the blast furnace, an operation in which relatively high temperatures are generated.

In one embodiment of the present invention,

lower shell sections

21, 22 are provided with stiffener bars 34 (FIG. 3) spaced circumferentially around the lower sections of the furnace and extending vertically from the bottom of hearth section 22 along the hearth and

bosh sections

22, 21. As shown in FIG. 3, shell hearth section 22 terminates at a bottom flange 24 secured to an underlying concrete foundation 26 by bolts 25.

Spaced around the periphery of the furnace at the top of the hearth section 22 are a plurality of tuyeres 23 for providing combustion gas to the interior of the fumace. In the interior of the furnace is a furnace bottom 27 composed of refractory material.

In the embodiment of FIG. 1, shell stack section 20 flares outwardly in a downwardly direction to accommodate thermal expansion of the charge material as it moves downwardly in the furnace. Bosh section 21 tapers inwardly in a downward direction to accommodate the decrease in volume of the charge material as it melts; and the hearth section 22 is essentially vertical.

Shell 10 includes a first transition portion 28 located at the junction of stack section 20 and bosh section 21, and transition portion 28 gradually changes laterally along a vertical dimension at said junction. The furnace shell also includes a second transition portion 29 located at the junction of bosh section 21 and hearth section 22, and second transition portion 29 also gradually changes laterally along a vertical dimension at said junction. Both

transition portions

28, 29 are continuous and uninterrupted. First transition portion 28, although located at the junction of the stack section and bosh section, is devoid of an expansion joint, a provision frequently utilized in conventional blast furnaces utilizing a mantle for supporting the stack section of the shell.

As described above, shell 10 has opposed side walls, substantial portions of which are in nonparallel relation. Other contours, in addition to the contour illustrated in the embodiment of FIG. 1, may be used in accordance with the present invention. Such additional contours are illustrated in FIGS. 4, 5 and 6 depicting

contours

31, 32 and 33 respectively.

The sole support of stack section 20 consists of

lower shell sections

21, 22, and the blast furnace shell does not require and does not include a mantle and columns for supporting the stack section. Accordingly, all the disadvantages inherent in structures utilizing mantles and supporting columns are eliminated with the one-piece, self-supporting blast furnace shells constructed in accordance with the present invention.

Referring to FIGS. 1, 2 and 14, the blast furnace shell is strengthened by a plurality of stiffening rings 40 spaced vertically from each other. Each ring 40 is located around the outside of blast furnace shell 10 and is radially spaced therefrom. Each stiffening ring 40 is attached to shell 10 by a plurality of circumferentially spaced bracket means 44. Referring to FIGS. 2 and 14, each stiffening ring 40 includes a horizontally disposed web portion 41, a vertically disposed inner flange portion 42 and a vertically disposed outer flange portion 43.

The stiffening rings 41 may also serve as catwalks around the exterior of the furnace, and, in this connection, attached to outer flange 43 of stiffening ring 40 is a post 39 to which rails (not shown) may be attached.

Each bracket means 44 is a vertically disposed plate having an innermost vertical edge 45 fixed to the outside of blast furnace shell 10 to attach stiffening ring 40 to the shell along, relatively, a vertical line. Inner vertical flange 42 of the stiffen ing ring is separated from the shell, e.g. shell stack section 20 in FIG. 2, by a space 46.

The vertical line attachment of stiffening ring 40 to shell and the spacing of the ring from the shell permit the shell to expand and contract, relative to stiffening ring 40, between the contracted position shown in full lines at in FIG. 2 and the expanded position shown in dotted lines at 47 in FIG. 2. The expansion and contraction takes place between adjacent bracket means 44 and occurs without permanently deforming the shell.

Referring to FIG. 14, located near the top of shell stack section 20 is a sprinkler pipe 48 from which a cooling fluid, such as water, is sprinkled onto shell 10 to trickle downwardly along the outside of the shell. Because stiffening rings 40 are spaced from the outside of the shell, the cooling fluid trickles downwardly, continuously, without interruption along the outside of the shell from above a stiffening ring to below the stiffening ring, through the space 46 between the stiffening ring and the outside of the shell, around substantially the entire periphery of the shell; and the flow of cooling fluid is continuous, without interruption from the upper part of stack section 20 to at least the lower part of bosh section 21 around substantially the entire periphery of the shell.

As shown in FIG. I, located alongside shell hearth section 22 are a plurality of cooling fluid sprinkler pipes 49 for cooling the hearth section. Near the bottom of the bosh and hearth sections are troughs 52 for collecting cooling fluid trickling down along the outside of the furnace shell.

Another type of external cooling device, water jacket 50, is shown in FIG. 1 above tuyere 23. The water jacket extends all the way around the periphery of the furnace. Water jackets may be located anywhere along the vertical dimension of the shell and are not restricted to the location above tuy ere 23.

The interior of a blast furnace having a shell in accordance with the present invention may be lined with conventional refractory material without the provision of internal cooling means for the refractory material; or the interior of the blast furnace may include metallic staves 17 (FIG. 14) provided with cooling fluid conduits as disclosed in Rosenak U.S. Pat. No. 3,3l4,668 or as described subsequently herein; or the refractory material lining the interior of the furnace may be cooled by conventional copper cooling plates 51 (FIG. 7).

The thickness of and type of support for refractory lining ll of stack section 20 depends upon the presence or absence of internal cooling structure. If the interior of the blast furnace contain metallic cooling staves, not only may the refractory lining be relatively thin but it may also be supported by the staves as described subsequently herein. If the refractory material is cooled with conventional copper cooling plates (FIG. 7), the copper cooling plates provide support for the refractory lining. If there is no provision for internal cooling in the blast furnace, the refractory lining must be relatively thick, and the refractory material 11 in stack section 20 may be supported by a ringlike bracket 60 extending around the interior of the furnace at the bottom of stack section 20 (FIG. 8).

Where the inward taper of bosh section 21 has a relatively large angle, as in embodiment 32 in FIG. 5, refractory lining 11 in stack section 20 is supported from below by bosh section shell 21.

When internal cooling is to be used in conjunction with onepiece shell 10, it is more desirable to use metallic cooling staves such as 17 (FIG. 14) rather than conventional copper cooling plates 51 (FIG. 7). This is because copper cooling plates extend through relatively large holes in the shell which are more difficult to seal than are the relatively small shell holes required by metallic cooling staves, as will be subsequently described.

By eliminating the major discontinuity in the shell at the junction of the stack section and bosh section, the major location of gas leakage is eliminated. By reducing other locations where gas leakage from the furnace interior has been a problem, the ideal of an absolutely gastight shell is much closer to reality.

Because a blast furnace having a one-piece, selfssupporting shell 10 does not require or utilize a mantle or columns, it is more economical to construct than conventional blast furnaces, and fabrication and installation of the furnace are simplified.

Because of the integral, one-piece construction, a hole in shell 10 caused by a furnace breakout, for example, would not endanger the structural integrity of the shell so much as would be the case if the shell were not of one-piece, integral construction. A much more sizeable hole would be required before the shell would be structurally unsafe than would be the case if the shell were not of integral, one-piece construction.

Referring now to the embodiment illustrated in FIGS. 9 and 10, located inwardly of a blast furnace shell 210 is a metallic lining extending continuously from the top of the stack section 220 to the lower part of the bosh section 221 and comprising a plurality of vertically stacked tiers each including a plurality of circumferentially arranged staves. The staves comprise, in vertically descending sequence, upper stack section staves 71, intermediate stack section staves 72, lower stack section staves 73 and bosh section staves 74. Located just above upper stack section staves 71 is an impact and wear absorbing ring comprising circumferentially arranged wear plates 14, previously described.

All of

staves

71, 72, 73, 74 are fluid cooled and are composed of cast iron. The furnace is thus provided with a fluidcooled metallic lining spaced inwardly of outer shell 210 and extending continuously, without interruption from the upper part of the stack section of the furnace to the lower part of the bosh section of the furnace.

The interior diameter of the blast furnace at the wear plates is substantially narrower than in the stack section therebelow to prevent excessive cooling in the space defined by wear plates 14 and to provide better control over material distribution into the furnace.

The inner surface of upper stack section stave 71 gradually curves along a vertical dimension from stack section 220 toward wear plate 14 to provide a smooth transition in the furnace interior from a relatively thin furnace wall at the stack section to the thicker wall at the hanging stock line defined by wear plates 14.

Lower stack section stave 73 has an inner surface gradually curving along a vertical dimension at the junction of the stack section and the bosh section to provide a smooth transition in the furnace interior between the furnace stack section and the furnace bosh section. This smooth transition from the stack section to the bosh section eliminates sudden changes of direction by the descending burden, the sudden change being an undesirable occurrence because it increases wear and causes severe changes in the interior furnace lines.

The lower part of bosh section stave 74 has an inner surface gradually curving along a vertical dimension from the previously described transition portion, at the junction of the stack and bosh sections, toward a hearth section 75 of the furnace interior. The curvature is toward bosh section 221 of the furnace shell; and, by thus curving, rather than by following the slope at the top of bosh section stave 74, the furnace interior is provided with a larger diameter at the bottom of the bosh section than it would otherwise have. This curvature also permits a larger internal diameter for interior hearth section 75 which conventionally extends vertically downwardly from the bottom of the bosh section of the furnace interior.

All of the staves 71-74 are covered with a thin lining, e.g. about 4 inches, of castible refractory 76 supported by the staves. A thin refractory lining is permissible because the staves are fluid cooled. Conventional thick refractory brick linings are eliminated.

Because the refractory is so thin, even if the refractory lining is worn away, the interior lines of the furnace are essentially the same. In other words, the furnace interior lines are essentially permanent. Thus, the furnace can be built initially with optimum lines, and these optimum lines are maintained during the entire time the furnace is operated.

The relatively thin refractory lining 76 also provides the furnace with a maximum interior volume for a given external diameter.

Not only the stack section but, also the bosh section of the furnace interior is cooled; and the thin castible refractory has a thickness which is essentially uniform from the top of the cooled metallic lining to the bottom thereof.

Each of the staves is movably mounted to accommodate radial movement of the metallic lining relative to the furnace shell during operation of the furnace. This mounting is illustrated in FIG. 1 1.

A typical stave, e.g. intermediate stack section stave 72, includes a recess 84 from which an opening 85 extends through the stave. The recess 84 receives the head of a bolt 86 extending through opening 85 and through a relatively small aligned opening 87 in shell 210 of the blast furnace. On the outside of the shell, bolt 86 is secured in place by a washer 88 and nut 89. A gastight seal is provided around shell opening 87 and comprises a tubular portion 90, the inner end of which is secured to shell 210, as by welding, and the outer end of which is closed by a cap 91. The staves are spaced slightly inwardly of shell 210, and the space between shell 210 and the staves is filled by a compressible resilient material 92 such as polyurethane foam, glass fiber, or the like.

As shown in FIG. 11 the top of each stave has a projection 83 received in a notch 82 in the bottom of the stave located thereabove. This notch-projection arrangement is also provided between upper stack section stave 71 and the bottom of wear plate 14. Wear plate 14 is suspended by a hook portion 80, at the top of the wear plate, engaging a bracket 81 attached to the interior of the furnace shell. Behind wear plate I4 a layer of castible refractory material 77 extending downwardly behind a portion of upper stack section stave 71. Wear plate 14 is mounted for vertical movement to accommodate vertical expansion of the wear plate and the underlying staves in response to thermal changes in the furnace interior, and this is described more fully in Slagley US. Pat. No. 3,202,407.

Referring to FIG. 13, each stave is provided with internal cooling coils 95 into which a cooling fluid, such as water, is introduced through an inlet conduit 96 and from which fluid is removed through an outlet conduit 97. As shown in FIG. 11, inlet and outlet conduits 96, 97 extend through respective openings 98 in furnace shell 210 and communicate with an external cooling fluid source (not shown).

Shell opening 98 is sealed with an arrangement comprising an accordion pleated, stainless steel expansion tube 99, the inner end of which is secured to a ring 100 in turn secured to shell 210. The outer end of accordion pleated tube 99 is closed by a cap 101 through which conduit 96 extends. The entire arrangement is gastight. Accordion pleated tube 99 permits conduit 96 to move inwardly and outwardly through shell opening 98 in response to similar movement by stave 72.

Insulating material 92, between furnace shell 210 and the staves forming the internal metallic lining of the furnace, thermally insulates the shell from the internal lining.

Referring to FIGS. 12 and 13, each of the staves 7'l-74 has a plurality of respective projections extending inwardly from the staves for performing a wear resisting function, now to be described.

Referring initially to FIG. 13, each upper stack section stave 71 has a series of horizontal and vertical ridges arranged in a grid and defining a multiplicity of boxes or recesses 105. The charge materials adjacent staves 71 are not heated to a high enough temperature to become sticky and will not build up on or stick to the surface of the staves. The boxes 105 will trap some of this charge material, and the descending charge will wear against the trapped charge material. In effect, the charge material is wearing upon itself rather than upon the staves.

The condition of the charge material adjacent staves 71 is such that there is relatively little wear on these staves. Most failures in conventional furnace linings in this upper part of the furnace are due to severe temperature changes when the level of the charge material changes. The fluid-cooled staves described herein and constructed in accordance with embodiments of the present invention are able to tolerate these temperature changes.

Each intermediate stack section stave 72 includes a multiplicity of cleats or protrusions 106. The charge material adjacent these intermediate staves is heated to a relatively high temperature and is sticky or tacky, although not liquid. Cleats 106 constitute anchors for the sticky charge material so that charge material will either adhere to the cleats or will be slowed down as it moves past the cleat-containing staves, thereby reducing or eliminating wear on the interior surface of a stave 72.

The same type of cleats 106 may also be provided on the upper part of lower stack section stave 73; but the lower part of stave 73 and all of bosh section stave 74 have protrusions in the form of horizontally extending ledges or ridges 107 (FIG. 12). Adjacent these ledges 107, the furnace contains liquid slag. Ledges 107 assist in freezing and retaining the liquid slag to provide a self-replenishing protective wear face on the staves. The thickness of the protective covering of slag may vary from one inch to four inches depending upon furnace conditions. Ledges 107 not only aid in building a slag wear face on the inner surface of the staves but also provide breaking lines along which the slag will peel if it breaks away from the staves, thus causing the slag to break off in relatively small sections which expose less interior surface of the stave than if the slag broke off in large sections. In lieu of horizontal ledges 107, the same function could be performed by horizontally extending corrugations.

Located between stack shell section 220 and lower stack section stave 73 is a layer of castible refractory 112 (FIG. 10); and located between bosh section stave 74 and bosh shell section 221 is another layer of castible refractory material 113.

Refractory layers

112, 113 help maintain

staves

73, 74 in position and provide additional protection in case of a stave failure. As shown in FIG. 10, located inwardly of shell hearth section 222 is a lining of refractory brick 111.

In the embodiment illustrated in FIGS. 9 and 10, the furnace is depicted as having a shell 210 of conventional construction with a mantle 211 at the junction of shell stack section 220 and shell bosh section 221. In this embodiment, the stack section staves 71, 72 are supported in vertically descending order by the stave therebelow, an d lower stack section stave 73 is attached to a bracket resting on mantle 2 l 1 Fluid-cooled metallic linings for blast furnaces in accordance with the present invention may also be used with an integral, continuous, one-piece, self-supporting blast furnace shell 10 such as that illustrated in FIG. I. In such a case, the entire support for the internal metallic lining would be only the blast furnace shell itself, the support being performed by bolts such as 86 (FIG. 11). A fluid-cooled metallic lining extending from the top of the stack section to the lower part of the bosh section is shown in FIG. 1, said staves being numbered 17 in the stack section and 18 in the bosh section.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art.

We claim:

1. A metallic blast furnace shell having a load-bearing superstructure contiguous to and supported by said shell, said shell being composed of steel and comprising;

in vertically descending sequence, a stack section, a bosh section and a hearth section, all joined together to form an integral, continuous, uninterrupted, one-piece blast furnace shell composed of said three shell sections;

said blast furnace shell being self-supporting and serving as the sole means for supporting said load-bearing superstructure;

said shell having opposed sidewalls which are in nonparallel relation for at least a portion of the vertical dimension of the shell;

the sole support for said stack section consisting of the shell sections located below the stack section;

each of said lower shell sections comprising means for imparting to said shell section sufficient strength to support the shell sections located thereabove and means for maintaining said strength during operation of the blast furnace; said strength imparting means comprising vertically extending stiffening means extending vertically along the outside of said shell upwardly from the bottom of said hearth section.

2. In a blast furnace shellas recited in claim 1 wherein said strength imparting means comprise elongated members.

3. In a blast furnace shell as recited in claim 1 wherein said elongated members comprise stiffener bars.

4. In a blast furnace shell as recited in claim 1, the junction of the stack section and bosh section being continuous, uninterrupted and devoid of an expansion joint.

5. In a blast furnace shell as recited in claim 4, said shell comprising a first transition portion gradually changing laterally along a vertical dimension at the junction of the stack section and the bosh section.

6. In a blast furnace as recited in claim 5, said shell comprising a second transition portion gradually changing laterally along a vertical dimension at the junction of the bosh section and the hearth section.

7. In a blast furnace shell as recited in claim 1, the sole support for said stack section consisting of the shell sections located below the stack section, whereby said blast furnace shell is devoid of a mantle for supporting the stack section and of columns for supporting said mantle.

8. In combination with the blast furnace shell of claim 1:

a stack section refractory lining located inwardly of the stack section of the shell;

a bosh section refractory lining located inwardly of the bosh section of the shell;

and means independent of the bosh section refractory lining for supporting said stack section refractory lining.

9. In a blast furnace shell as recited in claim 1:

a stiffening ring located around the outside of said shell and radially spaced therefrom;

a plurality of circumferentially spaced bracket means attaching said stiffening ring to said shell;

said bracket means comprising means for permitting the shell to expand and contract, relative to the stiffening ring, between said bracket means without permanently deforming the shell.

10. In a blast furnace shell as recited in claim 9, each of said bracket means comprising a vertically disposed plate having vertical edge means fixed to the outside of the shell to attach the stiffening ring to the shell along, relatively, a vertical line.

1 I. In a blast furnace shell as recited in claim 1:

and means for trickling cooling fluid downwardly, continuously, without interruption along the outside of said shell from an upper location above said stiffening ring to a lower location below the stiffening ring, through the space between the stiffening ring and the outside of the shell, around substantially the entire periphery of the shell.

12. In a blast furnace shell as recited in claim 1, means for trickling cooling fluid downwardly, continuously, without interruption along the outside of said shell from a location at the upper part of the stack section to a location at the lower part of the bosh section, around substantially the entire periphery of the shell.

Claims

1. A metallic blast furnace shell having a load-bearing superstructure contiguous to and supported by said shell, said shell being composed of steel and comprising; in vertically descending sequence, a stack section, a bosh section and a hearth section, all joined together to form an integral, continuous, uninterrupted, one-piece blast furnace shell composed of said three shell sections; said blast furnace shell being self-supporting and serving as the sole means for supporting said load-bearing superstructure; said shell having opposed sidewalls which are in nonparallel relation for at least a portion of the vertical dimension of the shell; the sole support for said stack section consisting of the shell sections located below the stack section; each of said lower shell sections comprising means for imparting to said shell section sufficient strength to support the shell sections located thereabove and means for maintaining said strength during operation of the blast furnace; said strength imparting means comprising vertically extending stiffening means extending vertically along the outside of said shell upwardly from the bottom of said hearth section.

2. In a blast furnace shell as recited in claim 1 wherein said strength imparting means comprise elongated members.

8. In combination with the blast furnace shell of claim 1: a stack section refractory lining located inwardly of the stack section of the shell; a bosh section refRactory lining located inwardly of the bosh section of the shell; and means independent of the bosh section refractory lining for supporting said stack section refractory lining.

9. In a blast furnace shell as recited in claim 1: a stiffening ring located around the outside of said shell and radially spaced therefrom; a plurality of circumferentially spaced bracket means attaching said stiffening ring to said shell; said bracket means comprising means for permitting the shell to expand and contract, relative to the stiffening ring, between said bracket means without permanently deforming the shell.

11. In a blast furnace shell as recited in claim 1: a stiffening ring located around the outside of said shell and radially spaced therefrom; a plurality of circumferentially spaced bracket means attaching said stiffening ring to said shell; and means for trickling cooling fluid downwardly, continuously, without interruption along the outside of said shell from an upper location above said stiffening ring to a lower location below the stiffening ring, through the space between the stiffening ring and the outside of the shell, around substantially the entire periphery of the shell.