US3554523A

US3554523A - Taphole assembly for metallurgical furnaces

Info

Publication number: US3554523A
Application number: US790121A
Authority: US
Inventors: Edwin B Miller
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-01-09
Filing date: 1969-01-09
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12

Abstract

A basic oxygen furnace taphole assembly which includes a prefabricated taphole outer portion and an inner portion having wedge shaped blocks for the taphole bottom, T-shaped blocks for its top, and conventional working lining bricks for its sides.

Description

United States Patent Edwin B. Miller 3002 Dunmurry Road. Baltimore. Md. 21222 Jan 9, 1969 Jan. 12, 1971 Inventor Appl. No. Filed Patented TAPHOLE ASSEMBLY FOR METALLURGICAL FURNACES 7 Claims, 11 Drawing Figs.

US. Cl 266/42, 13/331263/121266/35 lnLCl C2lb 7/12 Field of Search 266/ 35,

[56] References Cited UNITED STATES PATENTS 1,027,821 5/1912 Cunningham 266/38 3,153,110 10/1964 Sherburn etal. 266/43 3,227,434 1/1966 Voet et a1. 266/38 3,295,845 1/1967 Finn o 266/36 3,329,420 7/1967 Finn 266/42 3,416,779 12/1968 Campbell 266/36 3,463,475 8/1969 Buchholz 266/42 Primary Examiner-Gerald A. Dost Attorney-Joseph J. OKeefe ABSTRACT: A basic oxygen furnace taphole assembly which includes a prefabricated taphole outer portion and an inner portion having wedge shaped blocks for the taphole bottom, T-shaped blocks for its top, and conventional working lining bricks for its sides.

PAIENTED JAN 1 2:97: FW

sum 1 0r 3 Edwin B. Miller INVENTOR PATENTEU JAN 1 2 s97:

SHEET 2 [1F 3 INVENTOR Edwin B. Miller Pmmimmm 3.654.523

SHEET 3 OF 3 INVENTOR Edwin B. Miller TAPI'IOLE ASSEMBLY FOR METALLURGICAL FURNACES BACKGROUND OF THE INVENTION This invention relates to oxygen steelmaking vessels and more particularly to an improved taphole assembly for a basic oxygen furnace.

Steel produced in basic oxygen furnaces is poured from such vessels through pipelike tapholes fabricated from high temperature refractory material. l-Ieretofore, these tapholes have been formed in a variety of ways, all of which have one thing in common. They can be installed only when the furnace is in a vertical reline position and only after the working lining bricks have been installed to the elevation of the taphole. For example, one way of forming a taphole makes use of a prefabricated cylindrical assembly comprising two rings of arch bricks which are banded together around a pipe that forms the taphole. When the bricks of the furnace working lining have been laid up to the elevation of the taphole a cradle of rammed material is formed to receive the taphole assembly. The cylindrical taphole assembly is lowered through the mouth of the vessel and manhandled into position with its outer end extending through the taphole casting and its inner portion resting on the rammed material. The space between the outer surface of the cylindrical assembly and the straight sided brick of the furnace lining is rammed with a refractory material. Only after the taphole has been completed is it possible to set the remainder of the lining in place. Although this, as well as other types of tapholes have performed in a reliable manner, their general design and the procedures required for their placement, preclude their timely installation and result in excessive delays in furnace rebuilding operations.

SUMMARY OF THE INVENTION Therefore it is an object of the present invention to provide a superior taphole construction for a basic oxygen furnace.

It is another object of the invention to provide a taphole assembly which reduces to a minimum, as compared to presently used methods of construction, the time required for making such installations.

lt is another object of the invention to provide a taphole assembly which permits the rapid installation of a portion of the assembly from the charging floor, while the furnace is in a horizontal position and prior to the installation of the shell linmg.

A further object of the invention is to provide a taphole assembly which makes use of conventional refractory shapes of the working lining to form a portion of the taphole assembly thereby minimizing the number of specially shaped bricks required.

The objects of this invention are achieved by making use of a basic oxygen furnace taphole assembly which includes a prefabricated outer portion, that extends through the furnace safety lining, shell and taphole casting, and an inner portion that extends through the fumace-working lining. The taphole inner portion includes conventional working lining bricks for the sides of the taphole and specially shaped blocks for the top and bottom of the taphole. The bottom blocks are wedge shaped and have a horizontal bottom surface and an inclined upper surface which defines a bottom portion of the taphole. The top blocks are T-shaped and have a stern portion which has an inclined lower surface that defines a top portion of the taphole, the horizontally extending arms of the top blocks rest upon the bricks of the working lining which define side portions of the taphole.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings:

FIG. 1 is a section on line 1-1 of FIG. 2 and shows in sectional side elevation a basic oxygen furnace taphole assembly constructed in accordance with this invention.

FIG. 2 is a view in the direction of arrow A of FIG. 1.

FIGS. 3 and 5 are perspective views, partly broken away, illustrating a part of the outer portion of the taphole lining of this invention.

FIG. 4 is a view in the direction of arrow B of the assembly of FIG. 3 and showing the final step in the fabrication of the outer portion of the taphole lining of this invention.

FIG. 6 illustrates the manner in which the outer portion of the taphole lining of this invention is installed in a basic oxygen furnace tilted to the tapping position.

FIG. 7 is a perspective view, partly broken away, showing the construction of the inner portion of the taphole lining of this invention as viewed from the hot surface side of the working lining.

FIG. 8 is a perspective view, partly broken away, showing the construction of the inner portion of the taphole lining of this invention as viewed from the shell side of the working lining.

FIG. 9 is a perspective view of a top block of the inner portion of the taphole lining of this invention.

FIGS. 10 and 11 are perspective views of bottom blocks of the inner portion of the taphole lining of this invention.

PREFERRED EMBODIMENT OF THE INVENTION Referring to FIG. 1 there is shown only so much of a basic oxygen furnace 10 as will sufiice to illustrate the invention. Furnace 10 has a shell 11, safety lining 12 which is formed by bricks 13 in contact with the inside surface of the shell, and working lining 14 which is formed by bricks l5. Shown are portions of two of the three major sections of the furnace, barrel section 16 and cone section 17. Cone section 17 is of downwardly opening truncated cross-sectional configuration and forms an obtuse angle with barrel section 16. The majority of bricks 13 of safety lining 12 and bricks 15 of working lining 14 are conventional key bricks some of which are cut in the field to insure proper installation of the lining. Safety lining I bricks 13 in both barrel section 16 and cone section 17 are disposed with their sides perpendicular to the shell. Thus, when furnace 10 is in a vertical position the sides of safety lining bricks 13 in cone section 17 form an acute angle with the horizontal and in barrel section 16 they are horizontal. On the other hand, working lining bricks 15 in both barrel section 16 and cone section 17 are disposed so that their sides are in a horizontal plane, when furnace 10 is vertical. Thus, the sides of working lining bricks 15 are perpendicular to shell 11 in barrel section 16 but form an acute angle with the shell 11 in barrel section 16 but form an acute angle with the shell in cone section 17. Shell 11 has a thickness T, safety lining 12 has a thickness Ts and working lining 14 has a thickness Tw. Extending outwardly from the shell in cone section 17 is casting nozzle 18 which surrounds shell opening 19 that is circular in shape and has a diameter D. Nozzle 18 has a length l and the same inside diameter D as the diameter of shell opening 19. Spaced from shell opening 19 and extending inwardly of the shell are straight retainer bars 20. Extending through working lining 14, safety lining 12, shell 1l-and casting nozzle 18 is taphole assembly 21 of this invention. Tapholeassembly 21 includes outer section or nozzle block section 22, which extends through safety lining l2, shell opening 19 and casting nozzle 18, and inner section or working lining section 23, which extends through working lining l4. Extending longitudinally through taphole assembly 21 is taphole 24 having working lining section portion 24W and nozzle block section portion 24N.

Taphole assembly nozzle block section 22, shown in details in FIGS. 1, 3, 4 and 5, is a prefabricated assembly having a cylindrical outer portion 25 and a straight sided inner portion 26. Nozzle block section 22 has an outer end 27 and an inner end 28. Nozzle block section 22 has a length L which is ap proximately equal to the length l of casting nozzle 18, thickness T of shell 11 and thickness Ts of safety lining 12. Taphole portion 24N of taphole assembly nozzle block section 22 has a diameter d and the cylindrical outer portion 25 of taphole assembly nozzle block section 22 has a diameter which is slightly smaller than the inside diameter D both of casting nozzle 18 and shell opening 19 to allow the cylindrical outer portion to be easily inserted into the casting nozzle. Cylindrical outer portion has a length L0 which is slightly larger than the length l of casting nozzle 18 plus the thickness T of shell 11. Nozzle block section inner portion 26 has a shell or shoulder face 29 and parallel to it a working lining face with is inner end 28 of nozzle block section 22. Nozzle block inner portion 26 has four straight sides, top face 30, bottom face 33 and

side faces

32 and 33, all of equal length Lf. Nozzle block section inner portion 26 has a length Lf from its inner end 28 to shell face 29 which is slightly less than the thickness Ts of safety lining 12. The length Li of

sides

36, 31, 32 and 33 of nozzle block section inner portion 26 is larger than diameter D of shell opening 19 so that shell face 29 of the inner portion acts as a shoulder around shell opening 19. Nozzle block section inner end 28 is provided with recess 34 having a depth r. Recess 34 has bottom surface 35, which extends perpendicular to taphole 24, upper face 36,

side faces

37 and 38 and lower face 39. Recess

side faces

37 and 38 are perpendicular to recess bottom surface 35. Recess upper face 36 is inclined and forms an obtuse angle 2 with recess bottom surface and recess lower face 39 is parallel to upper face 36 and forms an acute angle y with bottom surface 35. As shown in FIG. 1, recess upper face 36 and lower face 39 are horizontal when nozzle block section 22 is installed in cone section 17 and furnace 10 is in a vertical position.

In a preferred embodiment of taphole assembly nozzle block section 22, the section is formed as follows: a pipe 40 having an outside diameter equal to diameter d of taphole portion 24N of nozzle block section 22 is placed upright on a lifting plate, not shown, which facilitates handling of the completed assembly. A first or inner cylinder 41 is constructed of arch bricks 42 and wedge bricks 43. Inner cylinder 41 has a length Lc which is equal to length L of taphole assembly nozzle block section 22 less the depth r of nozzle block section recess 34. Each arch brick 42 has a narrow edge 44, a

"broad edge 45, inclined sides 46, and ends 47. Each wedge brick 43 has a narrow end 48, a broad end 49, inclined sides 50, and edges 52. Arch bricks 42 are laid up in rows, for example A, B, C and D, with several bricks to a row, as shown in FIG. 3, with the narrow edges 44 of the arch bricks contiguous to pipe 40 and their broad edges 45 spaced from the pipe. Each third row of bricks, for example rows A and D, includes a single wedge brick 43 which is laid with its narrow end 48 contiguous to pipe 40 and its broad end 49 spaced from the pipe so that the outer portion of the wedge bricks extend outward beyond the broad edges 45 of arch bricks 42, for reasons hereinafter disclosed. Wedge bricks 43 are placed in inner cylinder 41 intermediate its ends and closer to theinner end which forms a portion of recess bottom surface 34 of nozzle block section inner portion 26 than to the outer end which forms a portion of nozzle block section outer end 27. The joints between bricks in one row are staggered with respect to the joints of the bricks of adjoining rows to break the bond. A second or outer cylinder 52 of arch bricks 53 is formed around inner cylinder 41 at its outer end. Outer cylinder arch bricks 53 are obviously of a larger size than arch bricks 42 of inner cylinder 4ll and have their narrow edges 54 laid against the broad edges 45 of arch bricks 42 of inner cylinder 41 and the broad edges 55 of outer cylinder arch bricks 53 form the outer part of the outer surface of cylindrical outer portion 25 of taphole assembly nozzle block section 22. After inner and

outer cylinders

41 and 52, respectively, have been formed, they are banded with steel strapping 56 for additional strength. A collar casting mold, not shown is then placed over the banded cylinders. A castable refractory material, such as a 95 percent MgO castable mix, is poured, into the mold against the inner ends of outer cylinder arch brick 53 and the broad outer edges 45 of arch brick 42 of inner cylinder 41 not covered by arch bricks 53 of outer cylinder 52, and around the outer portions of wedge bricks 43. The castable refractory material sets into a monolithic structure 57 which along with a portion of arch bricks 42 of inner cylinder 41 forms the inner portion of cylindrical outer portion 25 and straight sided inner portion 26 of nozzle block section 22. Thereafter, the mold is removed, any portion of pipe 40 extending beyond bottom surface 35 of recess 34 is cut off, and taphole assembly nozzle block section 22 is ready for installation.

Taphole assembly working lining section 23, shown in FIGS. 1, 2, 7 and 8, includes, as best shown in FIG. 2, top portion 58, bottom portion 59 and side or jamb portions 60 and 61, all of which define working lining section taphole portion 24W. Working lining section taphole portion 24W has a square cross section with a width W equal to diameter d of nozzle block section taphole portion 24N. T-shaped blocks 62, cut as hereinafter described, are used to form taphole assembly working lining section top portion 58, and the number of such blocks required is dependent upon the thickness of working lining 14 and the ability of brick manufacturers to form blocks 62 of highly refractory materials processed to high densities. In the embodiment shown, top portion 58 is composed of six

blocks

63, 64, 65, 66, 67, and 68 cut from T-blocks 62. Taphole assembly working lining section bottom portion 59 is composed of inside block 69 and outside block 70 both of which have a wedge shape in vertical longitudinal cross section. Side or jamb portions 60 and 61 are composed of conventional working lining bricks 15 some of which may be cut in the field to stagger the joints between rows of working lining bricks and to accurately position the bricks of the taphole assembly working lining section 23 so that working lining section taphole portion 24W is aligned with taphole portion 24 of nozzle block section 22. Y

T-block 62, shown in FIG. 9, has inner face 71, outer face 72, horizontal top portion 73 and a vertical stem portion 74. Top portion 73 has

side portions

75 and 76 which extend outwardly beyond stem portion 74 and these sides have

bottom surfaces

77 and 78, respectively, that in the taphole assembly working lining section rest upon the bricks of jamb portions 60 and 61, respectively. Stern portion 74 has the same width W as that of working lining section taphole portion 24W. Stem portion 74 has

sides

79 and 80, which abut the bricks of working lining section jamb portions 60 and 6t, respectively, and bottom all.

Blocks

63, 64, 65, 66, 67, and 68 forming taphole assembly working lining section top portion 58 are each formed from a T-block 62 which has had stem portion bottom 81 cut outwardly and upwardly, from inner face 7 l to outer face 72, as indicated by dotted line in FIG. 9, and as hereinafter described.

Taphole assembly working lining section inside bottom block 69, as shown in FIG. M), has the same width W as that of working lining section taphole portion 24W. Inside bottom block 69, wedge shaped in longitudinal cross section, has small inner end 82, straight bottom 33, large outer end 84, top 85 that is inclined upwardly and outwardly from inner end to outer end, and sides 66 and 87. Outside bottom block 70, as

shown in FIG. ill, has the same width W as that of working lining section taphole portion 24W and inside bottom block 69 and is wedge shaped in longitudinal cross section. Outside bottom block 70 has small inner end 88, straight bottom 89, large outer end which is inclined upwardly and inwardly and forms an acute angle V with bottom 89, top 91 that is inclined upwardly and outwardly from inner end to outer end, and sides 92 and 93.

in practice the taphole assembly of the present invention is rapidly installed with a minimum of labor in a basic oxygen furnace that is being relined. As shown in FIG. 6, furnace 10 with the old working lining removed and the safety lining l2 in place is tilted to a horizontal position so that nozzle block section 22 which is secured to crane boom 94 can be inserted into taphole assembly opening 9.5 of working lining 14 in cone section 27 and centered above casting nozzle 1%. Nozzle block section outercylinder is coated with a slurry of air-set mortar, such as a 95 percent MgO air-set mortar, and then lowered so that it slips neatly into casting nozzle l8 and between retainer bars 20. With nozzle block section outer cylindrical portion 25 in casting nozzle 18, shell face 29 of inner portion 26 is adjacent shell 11', and nozzle block section inner end 28 is substantially coplanar with the inner face of safety lining 12. The straight sided inner portion 26 of nozzle block section 22 fits into opening 95 between the flat sides of safety lining bricks 13. Any small spaces between safety lining bricks 13 and faces 30, 31, 32 and 33 of nozzle block inner portion 26 are rammed with a refractory material such as a 95 percent MgO castable mix. A locking device, not shown, is secured to noule block section 22 to hold it in position while the furnace is rotated to the vertical position and thereafter while the working lining is installed up to the elevation of the taphole assembly.

With furnace in a vertical position, bricks of working lining 14 are laid in the furnace as high as row E, shown in FIGS. 1, 2, 7 and 8, which is the elevation at which taphole assembly working lining section 23 is to be started, and the nozzle block locking device is removed. As shown in FIGS. 7 and 8, working lining bricks 15a, cut to approximately one-half length, is set in place on top of brick course E in front of nozzle block section 22 and in line with its taphole portion 24N. Taphole assembly working lining section outside bottom block 70 is laid with its bottom 89 on top of working lining brick 15a so that bottom block inclined outer end 90 extends into nozzle block section inner portion recess 34, and contiguous with recess bottom surface 35. Taphole assembly working lining section inside bottom block 63 is laid with its bottom 83 on top of working lining course E in line with outside bottom block 70. Outside and inside block inclined tops 91 and 85, respectively, are coplanar with one another and with a plane extending tangentially of the bottom of nozzle block section taphole portion 24N.

With bottom blocks 69 and 70 in position, rows F, G, and H of working lining bricks 15 are set in position with

bricks

15b, 15c, and 15d extending upwardly on one side of the bottom blocks and

bricks

15e, 15f, and 15g extending upwardly on the other side of the bottom blocks. As shown in FIGS. 1, 7 and 8 working lining bricks 15h and 15:, cut to approximately onehalf length, are set in place on top, of

bricks

15d and 15g, respectively, of row H with their outer ends contiguous with nozzle block inner portion recess bottom surface 35. Working lining split bricks 15j and 15k are set upon

bricks

15h and 15i, respectively, to satisfy elevation requirements for placement of the remainder of the working lining taphole section. T- block 68 is set in place with its stem portion 74 extending downwardly between split bricks 15j and 15k so that bottom surfaces 77 and 78 of its horizontal top portion 73 rest upon the tops of split bricks l5j and 15k, respectively. T-block 68 is cut so that outer face 72 of top portion 73 is inclined upwardly and inwardly and is contiguous with nozzle block inner portion recess bottom surface 35. T-blocks 67 and 66 are set in place in similar fashion, with outer face 72 of T-block 67 against inner face 71 of T-block 68 and outer face 72 of T- block 66 is against inner face 71 of T-block 67. Bottoms 81 of stem portions 74 of T-

blocks

68, 67, and 66 are cut on an incline so that they are coplanar with one another and with a plane extending tangentially of the top of nozzle block section taphole portion 24N.

Split bricks

151 and 15m are set upon the tops of bricks 15d and 153, respectively, of row H and extend inwardly from the ends of working lining bricks 15h and 151' respectively. T-block 65 is set in place, at a lower elevation than T-blocks 66, 67, and 68, with its stem portion 74 extending downwardly between

split bricks

151 and 15m so that bottom surfaces 77 and 78 of its horizontal top portion 73 rest upon the tops of split

bricks

151 and 15m, respectively. The outer face 72 of T-block 65 is contiguous with inner face 71 of T-block 66. T-blocks 64 and 63 are set in place in similar fashion with outer face 72 of T-block 64 against inner face 71 of T-block 65 and outer face 72 of T-block 63 against inner face 71 of T-block 64, Bottoms 81 of stem portions 74 of T-

blocks

65, 64 and 63 are cut on an incline so that they are

blocks

66, 67, and 68 and with a plane extending tangentially of the top of nozzle block section taphole portion MN. With T-blocks 63, 64, 65, 66, 67 and 68 in place, working lining

half bricks

15n and 150 are set in place on top of T-

blocks

63, 64, and 65. Rows F, G, H, l, J, and Kare completed around taphole assembly working lining section 23 arid the remainder of working lining 14 is laid in the normal manner.

Taphole assembly working lining section 23 thus formed has bottom portion 59 composed of bottom blocks 69 and 70; top portion 58 composed of T-

blocks

63, 64, 65, 66, 67 and 68; side portion 60 composed of working lining

bricks

15b, 15c, 15d, 151, 15h, and l5j, and side portion 61 composed of working

lining bricks

15e, 15f, 15g, 15m, 15i, and 15k. Inclined tops 85 and 91 of bottom blocks 69 and 70, respectively, define the bottom portion of working lining taphole portion 24N and inclined bottoms 81 of T-

blocks

63, 64, 65, 66, 67 and 68 define the top portion of working lining taphole portion 24N. The sides of working lining taphole portion 24N are defined by the aforementioned working lining bricks which compose side portions 60 and 61 of taphole assembly working lining section 23. in addition to bottom block 76 and top block 68 which have been described as extending into nozzle block section inner portion recess 34 working lining bricks 15 adjacent working lining taphole portion 24N, as shown in dotted line in FIG. 2, extend into recess 34.

The taphole assembly of the present invention is not limited to the number of shapes described. The size of the vessel in which the assembly is to be installed as well as the thickness of the working and safety linings and the desired density of the refractory shapes control the sizes of the shapes described and hence the number required for any particular taphole assembly.

The taphole assembly of this invention permits the installation of the one piece nozzle block section 22 while the vessel is turned down to a horizontal position, and the installation of working lining section 23 as bricks 15 of working lining 14 are laid in conventional fashion. By using the taphole assembly of this invention a basic oxygen furnace can be relined in a shorter time and with less man hours of labor than is necessary with taphole assemblies currently in use.

I claim: 1. In a metallurgical furnace having an outer metal shell, a refractory lining, and a taphole extending through said lining and shell, an improved taphole assembly comprising:

A. outer section having a portion of said taphole extending therethrough;

B. an inner section having a portion of said taphole extending therethrough and comprising, a. a wedge-shaped bottom block having:

1. a horizontal bottom surface;

2. an inclined upper surface extending upwardly and outwardly from the inner surface of said refractory lining and defining a portion of said taphole;

b. a T-shaped top block having:

1. a horizontal top portion;

2. a stem portion having an inclined bottom surface extending upwardly and outwardly from the inner surface of said refractory lining and defining a portion of said taphole.

2. The improved taphole assembly of claim 1 wherein the outer section is prefabricated and includes an inner portion having a recess disposed therein and said recess has a bottom surface which is perpendicular to said taphole and in the inner section said wedge-shaped bottom block has an upwardly and inwardly extending back end contiguous to said recess bottom and said T-shaped top block has an upwardly and inwardly extending back end contiguous to said recess bottom.

3. In a metallurgical furnace having an outer metal shell, an opening in said shell, a casting nozzle surrounding said opening and extending outwardly from said shell, a refractory safety lining adjacent said shell, a refractory working lining adjacent said safety lining, an improved taphole assembly extending through said working lining, said safety lining, said coplanar with one another and with the bottoms 81 of T- shell opening and said nozzle casting comprising:

A. a prefabricated section, having a longitudinally extending taphole, extending through said safety lining, said shell opening, and said casting nozzle and comprising:

a. a cylindrical outer portion, b. a straight sided inner portion.

4. The taphole assembly of claim 3 in which the prefabricated section cylindrical outer portion extends through the shell opening and casting nozzle and the straight sided inner portion has a width greater than the diameter of the cylindrical outer portion and extends through the safety lining.

5. The taphole assembly of claim 4 in which said straight sided inner portion has a recess extending outwardly from the inner end thereof and said recess has:

A. a bottom surface perpendicular to said taphole;

B. a straight top side which forms an obtuse angle with said bottom surface;

C. a straight bottom side which forms an'acute angle with said bottom surface.

6. In a basic oxygen furnace of the type having a cone section and including an outer metal shell, a safety lining, a working lining, and an inclined taphole extending through said working lining, said safety lining, and said shell, an improved taphole assembly, having a longitudinally extending taphole, comprising:

A. an inner section surrounding said taphole and having an outer end perpendicular to said taphole comprising: a. a first wedge-shaped bottom block having:

1. an inner end adjacent the inner surface of said working lining;

2. a horizontal bottom;

3. an inclined top extending upwardly and outwardly from said inner end and defining a bottom portion of said taphole;

4. a vertical outer end;

b. a second wedge-shaped bottom block, at a higher elevation than said first bottom block and spaced from the inner surface of said working lining, having:

1. an inner end spaced from the inner surface of said working lining;

2. a horizontal bottom;

3. an inclined top extending upwardly and away from said inner end and defining a bottom portion of said taphole;

4. an inclined outer end extending upwardly and inwardly at an acute angle from said bottom and defining a portion of said outer end of the taphole assembly inner section;

c. a first T-shaped top block having:

I. a vertical inner face;

2. a horizontal top portion;

3. a stem portion having an inclined bottom extending upwardly and outwardly from said inner face and defining a top portion of said taphole;

4. a vertical outer face;

a second T-shaped top block at a higher elevation than said first top block, spaced from the inner surface of said working lining, and having;

1. a vertical inner face;

2. a horizontal top portion;

3. a stem portion having an inclined bottom extending upwardly and outwardly from said inner face, and defining a top portion of said taphole;

4. an inclined outer face extending downwardly and outwardly from the top of said horizontal top portion and defining a portion of said outer end of the taphole assembly inner section.

7. The improved taphole assembly of claim 6 in which said first and second T-shaped top block top portions have a width greater than the width of said taphole and said first and second T-shaped top block stem portions have a width approximately equal to the width of said taphole.

@ 5 3? UNITED STATES PA'IEN'I OFFICE CERTIFICATE OF CORRECTION Patent No. 3,55 ,5 3 Dated January 1 97 Inventor(s) Edwin ller It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[- Column 1, line 7, the following has been omitted 'Assignee: Bethlehem Steel Corporation, a. corporatio;

of Delaware".

Signed and sealed this 6th day of July 197 (SEAL) Attest:

EDWARD I-I .FLETCHER,JR. WILLIAM E. SCHUYLER, .JR Attesting Officer Commissioner of Patents

Claims

1. In a metallurgical furnace having an outer metal shell, a refractory lining, and a taphole extending through said lining and shell, an improved taphole assembly comprising: A. outer section having a portion of said taphole extending therethrough; B. an inner section having a portion of said taphole extending therethrough and comprising: a. a wedge-shaped bottom block having: 1. a horizontal bottom surface; 2. an inclined upper surface extending upwardly and outwardly from the inner surface of said refractory lining and defining a portion of said taphole; b. a T-shaped top block having: 1. a horizontal top portion; 2. a stem portion having an inclined bottom surface extending upwardly and outwardly from the inner surface of said refractory lining and defining a portion of said taphole.

2. an inclined upper surface extending upwardly and outwardly from the inner surface of said refractory lining and defining a portion of said taphole; b. a T-shaped top block having:

2. a horizontal bottom; 3. an inclined top extending upwardly and outwardly from said inner end and defining a bottom portion of said taphole;

2. a horizontal bottom;

2. a horizontal top portion;

3. In a metallurgical furnace having an outer metal shell, an opening in said shell, a casting nozzle surrounding said opening and extending outwardly from said shell, a refractory safety lining adjacent said shell, a refractory working lining adjacent said safety lining, an improved taphole assembly extending through said working lining, said safety lining, said shell opening and said nozzle casting comprising: A. a prefabricated section, having a longitudinally extending taphole, extending through said safety lining, said shell opening, and said casting nozzle and comprising: a. a cylindrical outer portion, b. a straight sided inner portion.

4. an inclined outer end extending upwardly and inwardly at an acute angle from said bottom and defining a portion of said outer end of the taphole assembly inner section; c. a first T-shaped top block having:

4. a vertical outer end; b. a second wedge-shaped bottom block, at a higher elevation than said first bottom block and spaced from the inner surface of said working lining, having:

4. a vertical outer face; d. a second T-shaped top block at a higher elevation than said first top block, spaced from the inner surface of said working lining, and having;

5. The taphole assembly of claim 4 in which said straight sided inner portion has a recess extending outwardly from the inner end thereof and said recess has: A. a bottom surface perpendicular to said taphole; B. a straight top side which forms an obtuse angle with said bottom surface; C. a straight bottom side which forms an acute angle with said bottom surface.

6. In a basic oxygen furnace of the type having a cone section and including an outer metal shell, a safety lining, a working lining, and an inclined taphole extending through said working lining, said safety lining, and said shell, an improved taphole assembly, having a longitudinally extending taphole, comprising: A. an inner section surrounding said taphole and having an outer end perpendicular to said taphole comprising: a. a first wedge-shaped bottom block having: