JP7190379B2 - checkered brick - Google Patents

Description

TECHNICAL FIELD The present invention relates to a checker brick that is incorporated in a heat storage chamber of a hot stove.

A hot blast furnace is used to supply hot air to a blast furnace for ironmaking. In the heat storage chamber of the hot stove, a large number of checker bricks (also called gitter bricks) made of refractory bricks having a regular hexagonal prism shape are arranged in multiple layers as a heat storage material.

The checker brick has a regular hexagonal prism-shaped main body made of a refractory brick material, and the upper and lower surfaces of the main body are parallel to each other. A plurality of gas flow passages having a circular or hexagonal cross section are formed through the main body in the vertical direction, and each of the gas flow passages is opened on the upper and lower surfaces of the main body. In addition, since checker bricks are fired in open joints, in order to prevent the bricks from slipping, convex dowels (convex dowels) on either the upper or lower surface and concave dowels on the other of the upper or lower surface are used to prevent the bricks from slipping. (concave dowels).

In recent years, with the aim of improving thermal efficiency, the number of gas passages (number of holes) per unit area of checkered bricks has tended to increase. Checker bricks are also being used. However, especially with the checker brick having 37 holes, the thickness of the wall partitioning the gas flow path is as thin as, for example, 17 mm or less, which makes it difficult to manufacture. Furthermore, with the conventional size and position of the dowel, the dowel straddles the gas flow path, making it difficult to design the size and position of the dowel.

While such problems have been pointed out, Patent Document 1 describes a 37-hole checker brick with a wall thickness of 15 mm, in which convex dowels and concave dowels are formed in solid portions (walls) between gas flow paths. It is disclosed that by doing so, a thin portion is not formed, and damage to the brick due to thinning can be prevented. However, with the checkered bricks of Patent Document 2, although ABC stacking is possible, there is a problem that straight stacking is not possible.
Here, ABC lamination is a lamination method in which the first layer of pattern A, the second layer of pattern B, and the third layer of pattern C are repeatedly laminated. This is a stacking method in which the upper layer of checkered bricks is piled up.

The work of building a hot stove is done by stacking checker bricks one by one inside the furnace, but the checker bricks must be piled up in 100 or more layers. It is the neck of the event.
Therefore, it is conceivable to shorten the furnace construction work time by joining several tens of checker bricks in advance to form an integrated block, and carrying the integrated block into the furnace for construction. At this time, using the checker brick disclosed in Patent Document 1, for example, when trying to manufacture a brick block with a diameter of about 1 m and a height of 5 stages, only ABC stacking is possible, so the side surface of the integrated block As a result, it becomes difficult to join the integrated blocks together.
When the integrated blocks are manufactured in advance in this way, if the straight stacking and the ABC stacking can be combined and stacked, the furnace construction work in the furnace will be facilitated.

On the other hand, in order to enable both ABC lamination and straight lamination, Patent Document 2 discloses that the midpoint of the line connecting the vertex and the center of the regular hexagon of the outer shape of the brick is placed on either the top surface or the bottom surface of the brick. Three convex dowels centered at an angle of 120 degrees between the centers are provided, and the center is the midpoint of the line segment that connects the apex of the regular hexagon of the brick outline and the center on either the upper or lower surface of the brick. A 19-hole checker brick is disclosed in which concave dowels are provided with a center-to-center angle of 60 degrees apart from convex dowels. However, if the arrangement structure of the dowels in this 19-hole checker brick is applied as it is to a 37-hole checker brick having a thin wall thickness of 15 mm and a hexagonal cross-section of the gas flow path as in Patent Document 1, There is a problem that the strength of the dowel portion becomes insufficient.

Japanese Patent No. 5993297 Chinese Utility Model Publication No. 201809372

The problem to be solved by the present invention is to provide a 37-hole checkered brick which has sufficient strength and can be used for both straight and ABC stacking.

In the 37-hole checker, the present inventors placed convex dowels on either the upper or lower surface of the brick, centered on the midpoint of the line segment connecting the vertex and the center of the regular hexagon of the exterior shape of the brick. 3 are provided with an angle of 120 degrees apart, and on either the upper or lower surface of the brick, a concave dowel centered on the midpoint of the line segment connecting the vertex and the center of the regular hexagon of the brick outline is attached to the convex dowel The test was carried out focusing on the fact that both straight stacking and ABC stacking are possible by setting the center-to-center angle apart by 60 degrees. As a result, in the 37-hole checker, the protruding dowel has a cylindrical shape that encloses the gas flow path, and there is a problem that chipping or cracking is likely to occur in the thin portion of the cylindrical protruding dowel during molding or lamination. I understood it. Further, by providing an R at the corner portion of the gas flow path included in the convex dowel and setting the minimum wall thickness of the tip portion of the cylindrical convex dowel to 3 mm or more, the cylindrical convex dowel has sufficient strength. It has been found that a checkered brick is obtained.

That is, according to the present invention, the following checker brick is provided.
A checker brick having an outer shape of a regular hexagonal column and having 37 gas channels with a regular hexagonal cross section penetrating the upper and lower surfaces,
On either the upper surface or the lower surface, a cylindrical convex dowel centered on the center of the gas flow path located at the midpoint of the line connecting the vertex and the center of the regular hexagon of the outer shape is attached. It has three so as to be separated by 120 degrees,
On either the upper surface or the lower surface, a concave dowel centered on the center of the gas channel located at the midpoint of the line segment connecting the vertex and the center of the regular hexagon of the outer shape is placed at an angle between the centers with respect to the convex dowel. has three so that are separated by 60 degrees,
The corner portion of the inner hole of the gas flow path has an R,
and the minimum thickness of the tip portion of the convex dowel is 3 mm or more,
Moreover, a checker brick in which the base outer diameter ODd of the convex dowel satisfies the following formula.
Lc<ODd≦Lc+1.8Tr
Lc: diameter of the inscribed circle of the gas flow path (mm)
Tr: wall thickness (mm)
K: convex dowel coefficient (where 0<K≤0.9)

Since the checker brick of the present invention has three convex dowels and three concave dowels at predetermined positions, both straight lamination and ABC lamination are possible. In addition, since the cylindrical protruding dowel has a shape that ensures sufficient strength, the strength of the brick is also sufficient. As a result, the integrated blocks can be manufactured by straight stacking without any problems, and when the integrated blocks are used for furnace construction work, adjacent integrated blocks can be easily joined together. . In addition, when joining the integrated blocks in the vertical direction, each layer of the integrated blocks can be stacked ABC, so the hexagonal vertices of the integrated blocks can be stacked so that they do not coincide to achieve a more uniform load distribution. In addition, since all the gas flow paths pass through the central position of the integrated block at any level, it is possible to prevent the occurrence of gaps between the integrated blocks.
In addition, even in conventional furnace construction work that does not use integrated blocks, straight stacking is partially used, and both straight stacking and ABC stacking are possible, which improves work efficiency.

The perspective view which shows the upper surface side of the checker brick which is one Embodiment of this invention. The perspective view which shows the lower surface side of the said checker brick. The top view which shows the upper surface of the said checker brick. Sectional drawing which shows the longitudinal section of the said checker brick. A bottom view showing the lower surface of the checker brick. FIG. 4 is an enlarged longitudinal sectional view of a convex dowel portion of the checker brick; The enlarged plan view of the convex dowel part of the said checker brick. FIG. 4 is an enlarged vertical cross-sectional view of a recessed dowel portion of the checker brick;

1 to 5 show a checker brick 20 that is one embodiment of the present invention. 1 is a state in which the top side of the checkered brick 20 is viewed obliquely, and FIG. 2 is a state in which the bottom side of the checkered brick 20 is viewed obliquely. 3 shows the upper surface of the checker brick 20, FIG. 4 shows the longitudinal section of the checker brick 20, and FIG. 5 shows the lower surface of the checker brick 20. FIG.

As shown in each figure, the checker brick 20 has a regular hexagonal prism-shaped brick body 21 having an upper surface 25, a lower surface 26, six side surfaces 27, and six corners 30 where the side surfaces 27 intersect with each other.
The brick body 21 has a plurality of gas passages 22 extending vertically from its upper surface 25 to its lower surface 26, and three gas passages 22 provided on the upper surface 25 of the brick main body 21 at intervals of 120 degrees when viewed from the center of the hexagon. Convex dowels 23, three concave dowels 31 provided on the lower surface 26 of the brick body 21 at intervals of 120 degrees when viewed from the center of the hexagon, and four side surfaces formed on each of the six side surfaces 27 of the brick body 21. It has a flat portion 271 , three first flow grooves 28 formed in the vertical direction, and one second flow groove 29 formed in each of the six corners 30 .

The brick body 21 is made of a refractory brick material formed into a regular hexagonal prism shape by formwork molding. It has a high compressive strength.

The gas flow path 22 is a through hole penetrating the brick body 21 in the vertical direction (in the axial direction of the regular hexagonal column).
Among the six side surfaces 27 of the brick body 21, the gas flow paths 22 are arranged between two side surfaces 27 facing in parallel with each other at 4, 5, 6, 7, 6, 5, and 4, respectively. They are arranged in seven rows so as to form a total of 37 pieces.
The gas channel 22 has an opening 221 formed in the upper surface 25 of the brick body 21 and an opening 222 formed in the lower surface 26 of the brick body 21 . The gas flow path 22 is preferably a tapered through hole whose diameter expands upward, and the opening 221 of the upper surface 25 is slightly larger than the opening 222 of the lower surface 26 .
The cross-sectional shape of the gas flow path 22 is a regular hexagon, and therefore the openings 221 and 222 are also regular hexagons. However, these hexagons have rounded vertices.
The gas flow passages 22 are arranged so that the sides of the hexagon face each other, and the walls 210 formed between the gas flow passages 22 are formed so as to have a substantially constant thickness and continue like a rib.
With such a shape, the thickness of the wall 210 from the surface facing the gas flow path 22 is constant, and the refractory brick material forming the wall 210 can function as a heat storage material without waste. Therefore, by using such regular hexagonal gas passages 22, the heat storage efficiency of the checker bricks 20 can be maximized.

The first channel grooves 28 are formed continuously from the upper surface 25 to the lower surface 26 at intermediate portions of the six side surfaces 27 of the brick body 21 (intermediate portions of the hexagonal sides of the upper surface 25 and the lower surface 26). there is
The cross-sectional shape of the first channel groove 28 is half of the regular hexagon, which is the cross-sectional shape of the gas channel 22, by a line connecting the midpoints of the opposing sides (a line segment that is the diameter of the inscribed circle). It is considered to be a shape cut into . Therefore, when the checker bricks 20 are arranged side by side, the first flow channel grooves 28 of the other checker bricks 20 are arranged to face each other. A space corresponding to is formed.
Three first channel grooves 28 are formed on each side face 27, and a total of 18 channels are formed on the brick body 21. As shown in FIG.

The second channel grooves 29 are formed continuously from the upper surface 25 to the lower surface 26 at the corners 30 (portions corresponding to the vertices of the hexagons of the upper surface 25 and the lower surface 26) where the six side surfaces 27 of the brick body 21 intersect with each other. ing.
The cross-sectional shape of the second channel groove 29 is obtained by cutting a regular hexagon, which is the cross-sectional shape of the gas channel 22, into 1/3 by a line connecting the midpoint of a pair of sides sandwiching one side and the center of the hexagon. It is considered to be a shape. Therefore, when three checker bricks 20 are arranged next to each other, the second flow passage grooves 29 of the other two checker bricks 20 are arranged to face each other, and these three facing second flow passages are arranged to face each other. A space corresponding to the gas flow path 22 is formed by the groove 29 .
One second channel groove 29 is formed at each corner of the brick body 21 , and a total of six in the brick body 21 as a whole.

In general, checker bricks similar to the checker brick 20 have a width of 180 to 320 mm and a height of 120 to 180 mm. Since the length reaches 40 m, considering the load applied to the checker brick 20 and the stress during thermal expansion, it is empirically preferable that the compressive strength is 40 MPa or more.

In the checker brick 20 of the present embodiment, as described above, 37 gas passages 22 are formed in the brick body 21, and 18 first passage grooves 28 of 1/2 cross section and 1/3 cross section are formed. Six second flow grooves 29 are provided.

As shown in FIGS. 1 and 3, the protruding dowel 23 is formed to protrude from the upper surface 25 of the brick body 21, and has a truncated cone shape (tapered shape) as a whole. , but the side surfaces are conical surfaces at a predetermined angle with respect to the upper surface 25. As shown in FIG.

3, the center C1 of the convex dowel 23 is arranged on a line segment S extending from the hexagonal apex P1 (where the two side surfaces 27 intersect) of the upper surface 25 to the center C2 of the upper surface 25. ing. There are three gas flow paths 22 on the line segment S except for the one concentric with the center C2. The center C1 of the central gas flow path 22A among the three gas flow paths is positioned at the midpoint of the line segment S. As shown in FIG. The convex dowel 23 has a center C1 on the line segment S and the same as the center of the central gas flow path 22A, and has a cylindrical shape that includes the gas flow path 22A. That is, the convex dowel 23 has a gas channel 22A having a truncated cone shape and a regular hexagonal cross section.

6A is an enlarged longitudinal sectional view of the convex dowel 23 portion, and FIG. 6B is an enlarged plan view of the convex dowel 23 portion. As shown in FIG. 6B, the six corner portions 223 of the gas flow path 22 included in the convex dowels 23 are all R5 . The outer diameter ODt of the tip portion 312 of the convex dowel 23 is 39 mm, the outer diameter ODd of the base portion 311 is 46 mm, the height H is 5 mm, the maximum inner diameter Lm of the gas flow channel 22 is 29 mm, and the inscribed circle of the gas flow channel 22 is has a diameter Lc of 25 mm. The minimum thickness Tp of the tip portion of the convex dowel 23 is (ODt (39 mm)-Lm (29 mm))/2=5 mm. The thickness Tr of the wall 210 of the brick body is 15 mm.

In this way, the convex dowel 23 has a cylindrical shape that includes the regular hexagonal gas flow path 22 in a plan view. It prevents it from becoming the starting point of This R can be set to R3 or more when it is desired to further enhance the effect of preventing cracks and chipping. In addition, when it is desired to secure the area of the gas flow path from the aspect of heat transfer efficiency, it is also possible to set it to R7 or less. In addition, in the present invention, the gas flow path 22 in which the corner portions 223 of the regular hexagon in plan view are rounded is also regarded as a regular hexagon.

In addition, since the convex dowel 23 has a truncated cone shape, the thickness of the tip portion 312 is thin, and the thickness of the corner portion 223 (minimum thickness Tp of the tip portion) of the regular hexagonal gas flow path is the thinnest. It's becoming If the tip minimum thickness Tp is too thin, the tip of the convex dowel 23 is likely to be chipped during brick molding. .

Furthermore, if the outer diameter of the convex dowel 23 is too large, a portion of the wall 210 is formed on the side surface in a protruding manner, and this protrusion is likely to be chipped during brick molding, resulting in a decrease in the strength of the dowel portion. Therefore, in the present invention, the base outer diameter ODd of the convex dowel 23 satisfies the following formula.
ODd=Lc+2Tr×K
Lc: diameter of the inscribed circle of the gas flow path (mm)
Tr: wall thickness (mm)
K: convex dowel coefficient (where 0<K≤0.9)
Further, in order to ensure the strength of the convex dowels during construction work or during use, the convex dowel coefficient K is preferably 0.5 or more.
When the gas channel 22 is tapered as in this embodiment, the diameter Lc of the inscribed circle of the gas channel 22 and the thickness Tr of the wall 210 differ in the vertical direction. The diameter Lc of the inscribed circle and the thickness Tr of the wall 210 are both specified on the surface (the upper surface in this embodiment) on which the convex dowels are formed.

In addition, by providing R at the base and the tip of the convex dowel 23, it is possible to obtain the effect of suppressing damage during construction work and during use. can.
Furthermore, since the convex dowels 23 are cylindrical, if the height of the convex dowels 23 is too high, the dowels are likely to be chipped during handling. Since it becomes difficult, the height of the convex dowel 23 can be 3 mm or more and 8 mm or less.
Moreover, the thickness Tr of the wall 210 of the brick body is preferably 13 mm or more in order to give the convex dowels 23 sufficient strength.

As shown in FIGS. 2 and 5, the recessed dowels 31 are recessed from the lower surface 26 of the brick body 21 . The inner shape of the recessed dowel 31 is a truncated cone shape (tapered shape), and its bottom surface is horizontal like the lower surface 26 , but its side surface is a conical surface having a predetermined angle with respect to the lower surface 26 .

5, the center C1 of the concave dowel 31 is arranged on a line segment S extending from the hexagonal apex P1 (where the two side surfaces 27 intersect) of the lower surface 26 to the center C2 of the lower surface 26. ing. There are three gas flow paths 22 on the line segment S except for the one concentric with the center C2. The center of the central gas flow path 22A among the three gas flow paths is positioned at the midpoint of the line segment S. As shown in FIG. The recessed dowel 31 is on the line segment S and has the same center C1 as the center of the central gas flow path 22A, and is formed in the peripheral wall 210 that forms the gas flow path 22A.
Further, the concave dowels 31 are tapered in the vertical direction (height direction) so that the operation of fitting them into the convex dowels 23 can be performed smoothly when the checker bricks 20 are vertically stacked. The concave bottom surface side) has a small diameter, and the portion opening to the lower surface 26 has a large diameter.

The concave dowels 31 are usually 2 to 5 mm on each side and 2 to 5 mm on the bottom when the convex dowels 23 and the concave dowels 31 are fitted together for the purpose of workability and preventing damage due to thermal expansion of bricks during use. It is formed so as to have a gap of 2 to 5 mm, and the size of the concave dowel 31 can be designed by applying these known techniques according to the size of the convex dowel 23 also in the present invention. By forming the recessed dowels 31, the thickness of the wall 210 surrounding the gas flow path 22A is partly shaved or thinned. Since they are connected and reinforced, there is little possibility of chipping or cracking as with the convex dowels 23 . Moreover, even if chipping occurs, since it is reinforced by the surrounding six walls 210, the spread of the chipping is suppressed, so there is no problem. Specifically, in this embodiment, the concave dowel 31 has an inner diameter IDt of 54 mm on the opening side, an inner diameter IDd of 45 mm on the bottom surface, and a depth F of 8 mm, as shown in FIG. 6C.

Here, three convex dowels 23 are arranged on the upper surface 25 of the brick body 21 at intervals of 120 degrees when viewed from the center of the hexagon, and concave dowels 31 are arranged on the lower surface 26 of the brick body 21 with respect to the convex dowels 23 at six positions. Three pieces are arranged at intervals of 60 degrees when viewed from the center of the square. That is, the convex dowels 23 and the concave dowels 31 are arranged at positions shifted by 60 degrees from each other. The distance between the convex dowel 23 and the concave dowel 31 from the vertex P1 is 1/2 of the line segment S. By arranging the convex dowels 23 and the concave dowels 31 in this manner, both ABC stacking and straight stacking are possible as in the case of Patent Document 2 described above.

Table 1 shows the results of a production test of a 37-hole checker brick.
In the examples and comparative examples shown in Table 1, 10 checker bricks each having the same arrangement pattern of gas passages as in FIGS. did. The material of the brick body was an alumina-silica system disclosed in Japanese Patent Application Laid-Open No. 2018-52776. Each concave dowel was sized to have a gap of 4 mm on one side and a gap of 3 mm on the bottom when fitted to each convex dowel.

Although Examples 1 to 3 differed in the convex dowel coefficient and the minimum wall thickness of the tip portion of the convex dowel, the condition of the convex dowel was good after molding and after firing.
In Comparative Example 1, since the minimum thickness of the tip portion of the convex dowel was 2 mm, which was smaller than the lower limit value of the present invention, chipping occurred in the tip portion of the convex dowel after molding in 8 out of 10 pieces.
In Comparative Example 2, the corner portion of the inner hole of the gas flow channel was not rounded, but chipping occurred at the tip portion of the convex dowel after molding in 5 out of 10 pieces.
In Comparative Example 3, since the convex dowel coefficient was 1.2, which was larger than the upper limit value of the present invention, chipping occurred on the side surface of the convex dowel after molding in 4 out of 10 pieces.
Example 4, with a wall thickness of 13 mm, gave good results.

20 checker brick 21 brick main body 210 solid portion 22 gas channel 221 opening 222 opening 23 convex dowel 25 upper surface 26 lower surface 27 side surface 271 side flat portion 28 first flow channel groove 29 second flow channel groove 30 corner 31 concave dowel C1 Center C2 Center P1 Vertex P2 Vertex S Line segment

Claims (2)

A checker brick having an outer shape of a regular hexagonal column and having 37 gas channels with a regular hexagonal cross section penetrating the upper and lower surfaces,
On either the upper surface or the lower surface, a cylindrical convex dowel centered on the center of the gas flow path located at the midpoint of the line connecting the vertex and the center of the regular hexagon of the outer shape is attached. It has three so as to be separated by 120 degrees,
On either the upper surface or the lower surface, a concave dowel centered on the center of the gas channel located at the midpoint of the line segment connecting the vertex and the center of the regular hexagon of the outer shape is placed at an angle between the centers with respect to the convex dowel. has three so that are separated by 60 degrees,
The corner portion of the inner hole of the gas flow path has an R,
and the minimum thickness of the tip portion of the convex dowel is 3 mm or more,
Moreover, a checker brick in which the base outer diameter ODd of the convex dowel satisfies the following formula.
Lc<ODd≦Lc+1.8Tr
Lc: diameter of the inscribed circle of the gas flow path (mm)
Tr: wall thickness (mm) 2. The checker brick according to claim 1, wherein the radius of the corner portion of the inner hole of the gas channel is R3 or more and R7 or less.

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