US3764260A

US3764260A - Blast furnace stove

Info

Publication number: US3764260A
Application number: US00280914A
Authority: US
Inventors: M Smith
Original assignee: Bethlehem Steel Corp
Current assignee: Bethlehem Steel Corp
Priority date: 1972-08-15
Filing date: 1972-08-15
Publication date: 1973-10-09
Anticipated expiration: 1990-10-09

Abstract

A blast furnace stove is provided with a plate steel wall which partially divides said stove into a combustion chamber and a checker chamber. The checkerwork is supported on a plurality of interlocked grids, which in turn is supported on a plurality of interlocked girders secured to columns disposed in housings rigidly affixed to the floor of said checker chamber.

Description

Oct. 9, 1973 United States Patent [191 Smith, Jr.

2,542,680 2/1951 Kinney et 432/217 3,488,041 1 1970 P ll t l. 432 217 Marvin 0. Smith, Jr., Bethlehem, owe e a l A N a R P U F r T m S A m LV B .m M M U U Primary Examiner-Edward G. Favors [73] Assrgnee: Bethlehem Steel Corporation, Attorney joseph J. O,Keefe Bethlehem, Pa.

[22] Filed: Aug. 15, 1972 [21] Appl. No.: 280,914

ABSTRACT A blast furnace stove is provided with a plate steel wall which partially divides said stove into a combustion chamber and a checker chamber. The checkerwork is supported on a plurality of interlocked grids, which in turn is supported on a plurality of interlocked girders secured to columns dis posed in housings rigchecker chamber.

References Cited UNITED STATES PATENTS idly affixed to the floor of said 1,860,368 Seaver 432/217 4 Claims, 6 Drawing Figures PATENTED OCT 9 I973 sum 1m 2 BLAST FURNACE STOVE BACKGROUND OF THE INVENTION This invention relates to regenerative stoves for heating furnace combustion air, and more specifically to improvements in blast furnace stoves.

Blast furnace stoves generally comprise an insulated cylindrical outer shell with a dome-shaped top and a flat bottom. The interior of the stove is divided into two sections, viz. a combustion chamber and a checker chamber. In the two-pass type of stove, gas is burned in the combustion chamber, which is made of refractory bricks, and passes upwardly to the dome. The hot products of combustion are then blown downwardly through the checker chamber, which comprises a refractory checkerwork having a plurality of flues therein, and exhausted into a stack through a chimney flue connection disposed at a point near the bottom of the stove. After the checkerwork has reached the desired temperature, combustion is stopped and cold blast air is blown into the checker chamber in the reverse direction. This air passes upwardly through the checkerwork, thereby becoming heated, passes downwardly in the combustion chamber, and is supplied through a hot blast connection to a blast furnace.

In the past, the checkerwork has been supported on a network of horizontally disposed grids with the grids in turn being supported on horizontally disposed girders. The girders were supported on columns which rested on the stove floor, thereby providing a space below the girders to which one or more chimney flue connections and one cold blast connection were made.

Examination of the checkerwork supporting structure during periods when the stove is shut down frequently has shown that the bottom courses of checkers are prematurely severely damaged, resulting in the need for early replacement of these courses.

In addition to the foregoing the supporting girders have occasionally become dislodged and columns have collapsed.

Furthermore, accelerated failure of the brick forming the combustion chamber has been discovered, particularly at points directly opposite the point where the combustion gas is fed into the combustion chamber and ignited. This also results in the need for early replacement of brickwork.

It is an object of this invention to provide a regenerative stove having a checkerwork supporting structure in which the bottom courses of checkers are not prematurely severely damaged.

It is a further object of this invention to provide a regenerative stove having means for preventing accelerated failure of the brick forming the combustion chamber.

SUMMARY OF THE INVENTION I have discovered that damage to the bottom courses of checkers and premature collapse of the girders and columns are caused by shifting of the elements comprising the checker-supporting system,and that such shifting and consequent damage can be minimized by providing a supporting system having the following characteristics. First, the bases of the columns are disposed in housings affixed to the floor of the stove, thereby limiting shifting of the columns along the floor. Secondly, the girders are all interlocked and secured to the tops of said columns by means to limit their movement. Thirdly, the grids which are supported on the girders are all interlocked.

I have also discovered that failure of the combustion chamber brick is due to the hot combustion gases bypassing the checkers and passing directly through cracks in the combsution chamber wall, thereby not adding heat to the checker work prior to discharge out the chimney flue connection. Likewise the cold blast air passes directly through the same cracks on the blowing cycle, thus bypassing the checkers and thereby not becoming heated prior to discharge out the hot blast connection. This problem can be eliminated by providing an upright, substantially semi-cylindrical steel plate between the combustion chamber wall and the checker chamber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation view of a blast furnace stove.

FIG. 2 is an enlarged sectional side elevation view showing details of the combustion chamber and checker supporting structure.

FIG. 3 is a portion of an enlarged sectional view through the lines 33 of FIG. 2.

FIG. 4 is a side elevation view, partly in section, showing details of the checker supporting structure.

FIG. 5 is a sectional half plan view, through the lines 5-5 of FIG. 2, showing the interlocked girders and related structure.

FIG. 6 is a sectional half plan view, through the lines 6-6 of FIG. 2, primarily showing the interlocked grids.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, the blast furnace stove of the invention broadly comprises a cylindrical steel outer shell 10 having a dome-shaped top 12 and a flat steel bottom 14 having a concrete floor 15 thereon supporting refractory brick 17. Within the shell 10 is a combustion chamber 16 and a checker chamber 18. The checker chamber 18 comprises checkerwork 20 resting upon a supporting structure broadly designated as 22. Below the supporting structure 22 is a space which communicates with a cold blast connection 24 and at least one chimney flue connection 26.

The combustion chamber 16 is provided with a burner opening 28. Disposed above the burner opening 28 is a hot blast connection 32. As shown in detail in FIGS. 2 and 3, the combustion chamber 16 is formed of refractory bricks 30. Disposed about the refractory bricks 30, in the vicinity of the burner opening 28, is a semi-cylindrical plate steel shell 34 comprising a lower section 36 and an upper section 38. Welded to the inside of the lower section 36 is an annular plate 40 which frictionally engages the inside of the upper section 38 and serves as a guide therefor during expansion and contraction of said upper section 38 during the heating and cooling cycles. The upper section 38 is held substantially in place by the surrounding refractory bricks 30, and is initially positioned so that there is a small distance 42 between the bottom edges thereof and the top edges of the lower section 36. This arrangement functions as a vertical thermal expansion joint.

The shell 34 is provided with a horizontal thermal expansion joint 44, shown more clearly in FIG. 3, comprising a split pipe 46 welded to each side of a vertical split in the shell 34. Dust and brick residue are prevented from entering the pipe 46 by providing a vertical cover plate 48, welded to one side only of the split in the shell and a horizontal cover plate 50, also welded to one side only of the split in the shell. The joint 44 is disposed in a space 52 provided in insulating brick 54, which brick fills the space between the checkers 20, the steel plate 34, and the steel outer shell 10.

As shown in FIG. 4, disposed on the stove bottom 14 and recessed in the concrete 15 and brick 17 is a plurality of column housings 56. In each housing is disposed a leveling assembly 58 comprising a bearing plate 68 and a bottom plate 62 interconnected by leveling screws 64. The housing is filled with a grout 66 after leveling of columns 56. As can be seen, the face of the bottom plate 62 is smaller than the cross-section of the housing 56; thus, the bearing plate 60 is capable of limited movement within the housing 56. The space immediateiy above the leveling assembly 58 is filled with a compressible refractory 67.

Each of a plurality of box-like columns 68 has its base welded to one of the bearing plates. Said columns 68 are adapted to provide a support for a plurality of interlocked girders 70, shown in detail in FIG. 5, and each column comprises a top plate 72 welded to side plates 74.

The girders 70 are welded to means for limiting movement comprising box-like cap members 76. Each of said cap members 76 comprises a bearing plate 78 and side plates 80. Each cap member 76 fits over the top of a column 68 and is capable of limited movement in the horizontal plane since the side plates 80 are spaced slightly from the column side plates 74.

As shown in FIG. 5, a pair of girders 70 is welded to each of the cap members 76, and each girder is parallel to every other girder and to the centerline of the burner opening 28. Each girder is spaced from the other girder forming the pair by a plurality of short spacer plates 82 welded therebetween. Each pair of girders is spaced from adjacent pairs by spacer plates 84, bolted together at 86, for example, and welded to the girders 70. In this manner, all of the girders 70 are interlocked and provide a support for grids 88, shown in detail in FIG. 6.

The grids 88 are thin plate members disposed perpendicularly to the girders 70. A plurality of grids 88 is formed into a section by means of spacers 9i) welded therebetween. The various sections are interlocked by means of bolts and spacer sleeves 92.

Immediately adjacent to the girders 70 and grids 88, and built into the brick wall 54, are steel bumper T- plates 94. The T-plates 94 prevent damage to the wall 54 during expansion of the girders 70 and grids 88 during heating.

The checkerwork rests on intermediate support ing means comprising cast steel shoes 21. The shoes 21 are supported by the grids 88, and are provided with male projections which interlock with female connections provided in the bottoms of the lowest row of checkers.

The operation of the subject blast furnace stoves is identical to that of prior art two-pass blast furnace stoves. However, because of the design of the checkerwork supporting structure, shifting thereof during the heating and cooling cycles and consequent damage to the bottom courses of checkers and collapsing of columns, girders and grids are minimized. In addition, because of the plate steel shell 34, bypassing of hot combustion gases during the heating cycle and the cold blast during the reverse cycle is prevented, thereby preventing accelerated failure of thebrick forming the combustion chamber.

I claim:

1. A regenerative stove for heating combustion air, comprising:

a. an outer shell, substantially cylindrically shaped,

having first and second openings therein for passing cold air into said stove and hot air out of said stove, said shell being lined with insulating brick,

b. an upright, steel plate partially dividing said stove into a combustion chamber and a checker chamher, said steel plate being rigidly affixed at its side ends to said outer shell,

c. a refractory wall adjacent said plate providing an enclosure for said combustion chamber,

d. a third opening in said outer shell, for introducing combustion gas into said combustion chamber,

e. a fourth opening in said outer shell, for removing combustion gas from said checker chamber,

f. a plurality of columns in said checker chamber, the bases of said columns being disposed in housings affixed to the floor of said stove,

g. a plurality of interlocked girders,

h. limitedmovement means securing said girders to the tops of said columns,

i. a plurality of interlocked grids resting upon said girders,

j. intermediate supporting means resting upon said grids, and

k. refractory checkerwork resting upon said intermediate supporting means.

2. A stove as recited in claim 1, in which steel bumper plates are embedded in the insulating brick wall adjacent to said grids.

3. A stove as recited in claim 1, in which said limitedmovement means (h) comprises a cap member rigidly affixed to a girder, said cap member abutting the top of a column and having four downwardly disposed sides, each of said sides being in close proximityto a side of said column. d

4. A stove as recited in claim 1, in which the plate (b) is provided with vertical and horizontal thermal expansion joints.

Claims

1. A regenerative stove for heating combustion air, comprising: a. an outer shell, substantially cylindrically shaped, having first and second openings therein for passing cold air into said stove and hot air out of said stove, said shell being lined with insulating brick, b. an upright, steel plate partially dividing said stove into a combustion chamber and a checker chamber, said steel plate being rigidly affixed at its side ends to said outer shell, c. a refractory wall adjacent said plate providing an enclosure for said combustion chamber, d. a third opening in said outer shell, for introducing combustion gas into said combustion chamber, e. a fourth opening in said outer shell, for removing combustion gas from said checker chamber, f. a plurality of columns in said checker chamber, the bases of said columns being disposed in housings affixed to the floor of said stove, g. a plurality of interlocked girders, h. limited-movement means securing said girders to the tops of said columns, i. a plurality of interlocked grids resting upon said girders, j. intermediate supporting means resting upon said grids, And k. refractory checkerwork resting upon said intermediate supporting means.

3. A stove as recited in claim 1, in which said limited-movement means (h) comprises a cap member rigidly affixed to a girder, said cap member abutting the top of a column and having four downwardly disposed sides, each of said sides being in close proximity to a side of said column.