Crushing method of refractory layer

Abstract

To provide a method of crushing and removing a deteriorated layer of a refractory layer of an inner surface of a vessel in a short time.SOLUTION: A crushing method of a refractory layer in which at least part of the refractory layer is crushed by a crushing tool when repairing a vessel having the refractory layer on an inner surface thereof includes: a first crushing step of crushing at least part of the refractory layer while moving, in a first direction of an inner surface of the vessel, the crushing tool along a first route set at intervals not overlapping therein so that regions to be crushed by the crushing tool are not overlapped; and a second crushing step of crushing at least part of the refractory layer while moving, in a second direction crossing the first direction of the inner surface of the vessel, the crushing tool along a second route set at intervals not overlapping therein so that the regions to be crushed by the crushing tool are not overlapped.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for crushing a refractory layer, in which, when repairing a vessel having a refractory layer on its inner surface, at least a part of the refractory layer is crushed by a crushing tool. [Background technology]

[0002] In general, containers for holding high-temperature contents are provided with a refractory layer as a lining on the inner surface to protect the container body from the heat of the contents. An example of a container having such a refractory layer is a container for holding molten metal (hereinafter referred to as a "molten metal container").

[0003] However, when such containers are used, the surface layer of the refractory layer gradually deteriorates due to wear caused by contact with the hot contents, structural spalling (cracks, peeling) caused by thermal shock, etc. Therefore, in order to maintain the functionality of the refractory layer, it is necessary to carry out periodic repairs.

[0004] A method of spraying a molded refractory is generally used as a method of repairing a refractory layer. However, when a molded refractory is sprayed on a deteriorated refractory layer, the interface between the deteriorated refractory layer (hereinafter referred to as the deteriorated layer) and the new refractory layer remains inside the repaired refractory layer. In addition, the surface of the deteriorated refractory layer may have molten metal, slag, and other build-up that adhered when the container was used. Therefore, when a crack occurs in the new refractory layer on the surface side during use of the container after repair, molten metal, etc., penetrates through the crack to the interface between the deteriorated layer and the new refractory layer, causing the new refractory layer to peel off.

[0005] Therefore, in order to prevent the above-mentioned peeling, when repairing the refractory layer, the surface of the area to be repaired is first scraped off, the deteriorated layer and any slag adhering to the surface of the refractory layer are removed, and then unshaped refractory material is sprayed on.

[0006] As a method for removing the deteriorated layer, for example, a method using large heavy machinery such as a hydraulic breaker can be mentioned. However, when such a large heavy machinery is used, the shaped refractory (firebrick) provided as the base of the unshaped refractory may be damaged.

[0007] Therefore, for example, Patent Document 1 proposes that when spraying and repairing the lining on the inner surface of a molten metal container, a repair device equipped with a crushing tool is used in advance to completely remove and dismantle the deteriorated layer on the surface of the refractory layer, rather than using heavy machinery as described above. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2006-292278 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, since the size of a typical crushing tool is about 200 to 300 mm in diameter, there was a problem that it took a long time to crush and remove the entire deteriorated layer on the surface of the refractory layer on the inner surface of a molten metal container using a crushing tool, as in the method proposed in Patent Document 1.

[0010] As an example, a case where a refractory layer in a rectangular area of ​​1900 mm in height and 1200 mm in width is crushed and removed by a crushing tool will be described. Figure 1 is a schematic diagram showing an example of a moving path of the crushing tool when the entire area is crushed by the crushing tool. The crushing tool is capable of crushing a refractory layer in a circular area S of 200 mm in diameter.

[0011] First, the crushing tool is moved to the upper left of the area, which is the starting point for crushing, and the refractory layer at that position is crushed. After that, the crushing tool is moved 100 mm to the right, and the refractory layer is crushed at the new position. The above process is repeated until the crushing tool reaches the right end of the area. This causes one level of refractory layer to be crushed in the lateral (horizontal) direction. In this example, 11 crushing operations are required to crush one level of refractory.

[0012] When crushing, the crushing tool is pressed against the refractory layer to crush the refractory layer in the circular region S to a desired depth. After that, the crushing tool is retreated to a position where it does not contact the remaining refractory layer, and then the crushing tool is moved.

[0013] Next, the crushing tool is moved downward. Specifically, the crushing tool is first moved downward by 85 mm, crushing is performed at that position, and then the crushing tool is moved downward by 85 mm again.

[0014] Next, the refractory layer at that position is crushed. After that, the crushing tool is moved 100 mm to the left, and the refractory layer at the position after the movement is crushed. The above process is repeated until the crushing tool reaches the left end of the region.

[0015] By repeating all of the above steps, the crushing tool can be moved back and forth from side to side to crush almost the entire area. In this example, 13 vertical stages are crushed. Therefore, in addition to 11 x 13 stage crushing, 11 crushing operations are performed while moving downwards, making a total of 154 crushing operations. Here, we have taken an example of crushing a relatively small area of ​​1900 mm x 1200 mm, but when repairing an actual container, especially a molten metal container used in industry, the entire inner surface of the container may be repaired, so it will take a considerable amount of time to crush the refractory layer.

[0016] The present invention has been made in consideration of the above circumstances, and has an object to provide a method for crushing and removing a deteriorated refractory layer on the inner surface of a container in a short period of time. [Means for solving the problem]

[0017] As a result of investigations to solve the above problems, the inventors discovered that by utilizing the back cracks that form as the refractory layer deteriorates, the deteriorated layer can be efficiently removed without crushing the refractory layer on the entire inner surface of the container.

[0018] Here, the process by which cracks form in a refractory layer in a typical molten metal container will be described with reference to the drawings. Fig. 2 is a schematic cross-sectional view showing how a refractory layer 10 provided on the inner surface of a container 1 deteriorates over time due to contact with molten metal, eventually resulting in partial peeling. Reference numeral 20 denotes a metal container body. When the container 1 is a molten metal container such as a ladle, the container body 20 is called a steel shell.

[0019] As shown in FIG. 2(a), surface cracks 11 are generated on the surface of the refractory layer 10 due to contact with the molten metal. Then, as shown in FIG. 2(b), an infiltration layer 12 is formed on the surface of the refractory layer 10, where the molten metal infiltrates the surface cracks 11, and grows toward the inside of the refractory layer 10 (arrow A). Meanwhile, a build-up layer 13 is formed on the surface of the refractory layer 10 by adhesion of slag and other slag, and grows toward the outside of the refractory layer 10 (arrow B). In this specification, the layer infiltrated by the molten metal is called the "infiltration layer", and the infiltration layer and the build-up layer are called the "deteriorated layer". In other words, the "infiltration layer" is included in the "deteriorated layer".

[0020] Eventually, due to the difference in thermal expansion coefficient between the undeteriorated refractory layer 10 and the impregnation layer 12, a back crack 14 occurs near the interface between the refractory layer 10 and the impregnation layer 12, as shown in Fig. 2(c). The generated back crack 14 gradually grows along the interface between the refractory layer 10 and the impregnation layer 12, and as a result, the interface between the undeteriorated refractory layer 10 and the impregnation layer 12 becomes prone to peeling.

[0021] If the container 1 is continued to be used in this state, the back crack 14 and the surface crack 11 will eventually connect as shown in Fig. 2(d). As a result, the infiltration layer 12 and the build-up layer 13 will peel off in the area surrounded by the surface crack 11 and the back crack 14 as shown in Fig. 2(e). In the area where the peeling has occurred, the sound refractory layer 10 will be exposed on the surface, and the deterioration of the refractory layer 10 will progress further from that area.

[0022] In this way, cracks form inside the refractory layer as the container is used, and so in the container to be repaired, there are parts where the infiltration layer is prone to peeling due to the presence of back cracks, as shown in Figure 2 (c) and (d). In such parts, even if the part is not crushed with a crushing tool, peeling may occur by crushing the surrounding area.

[0023] The present invention utilizes the above-mentioned peeling phenomenon caused by the back surface crack, and the main configuration thereof is as follows.

[0024] 1. A method for crushing a refractory layer in repairing a vessel having a refractory layer on its inner surface, comprising crushing at least a part of the refractory layer with a crushing tool, comprising: a first crushing step of crushing at least a part of the refractory layer while moving the crushing tool along a first path set at intervals so that regions crushed by the crushing tool do not overlap along a first direction of the inner surface of the container; and a second crushing step of crushing at least a part of the refractory layer while moving the crushing tool along second paths set at intervals from each other along a second direction intersecting the first direction on the inner surface of the container so that areas crushed by the crushing tool do not overlap.

[0025] 2. A determination step of determining whether or not at least a part of the refractory layer has peeled off in an uncrushed area of ​​the inner surface of the container surrounded by the first path and the second path after the second crushing step; 2. The method for crushing a refractory layer according to claim 1, further comprising: an additional crushing step of crushing at least a part of the refractory layer in the uncrushed region while moving the crushing tool along a third path passing through the uncrushed region when peeling of the refractory layer does not occur in the uncrushed region.

[0026] 3. The crushing tool is provided at one end of the crushing device; A reaction support device is provided at the other end of the crushing device, 3. The method for crushing a refractory layer according to claim 1 or 2, wherein, when crushing, the crushing tool is pressed against one of the opposing inner surfaces of the container, and the reaction support device is pressed against the other of the opposing inner surfaces. Effect of the Invention

[0027] In the present invention, at least a part of the deteriorated layer of the refractory layer on the inner surface of the vessel is crushed along the first path and the second path, which induces peeling of the deteriorated layer of the refractory layer in the area surrounded by the first path and the second path, and makes it possible to remove the deteriorated layer without crushing the refractory layer of the entire inner surface of the vessel, thereby shortening the time required for repair. [Brief description of the drawings]

[0028] [Figure 1] 10 is a schematic diagram showing an example of a moving path of a crushing tool when the entire surface of a refractory layer is crushed by the crushing tool; FIG. [Diagram 2] FIG. 2 is a schematic diagram showing a process in which a crack is formed in a refractory layer. [Diagram 3] FIG. 4 is a schematic diagram showing an example of a moving path of a crushing tool in the first embodiment. [Figure 4] FIG. 11 is a schematic diagram showing an example of a moving path of a crushing tool in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The present invention will be described in detail below. Note that the following description is an example of a preferred embodiment of the present invention, and the present invention is not limited to the embodiment described below. In addition, elements not mentioned in this specification can be the same as conventional repair methods.

[0030] [container] The present invention is directed to a vessel having a refractory layer on its inner surface. The vessel may be any vessel having at least a refractory layer on its inner surface. The vessel may, for example, have a vessel body made of metal and a refractory layer provided on the inner surface of the vessel body. The vessel body is typically made of steel and is also called a steel shell. The refractory layer is also called a lining.

[0031] The vessel may be, for example, a vessel for molten metal, such as a hot metal ladle, a ladle for molten steel, a refining vessel, or the like.

[0032] The present invention can be applied to a refractory layer having any material and structure. Therefore, the refractory layer provided on the inner surface of the container may be made of any material and structure as long as it is a layer made of a refractory material.

[0033] Also, it is common to configure the refractory layer as a lining with a layer of a shaped refractory called a "perm brick" and a layer of an unshaped refractory. For example, a typical molten metal container has a metal container body called a "skin", a layer of a shaped refractory (perm brick) provided on the inner surface of the container body, and a layer of an unshaped refractory provided on the inner surface of the shaped refractory layer, and the refractory layer is configured by the layer of the shaped refractory and the layer of the unshaped refractory. The present invention can also be suitably used for repairing a refractory layer having the above-mentioned structure.

[0034] In addition, the present invention is intended to crush and remove the refractory layer when repairing the container. Therefore, the container may be a used container. Furthermore, at least a part of the surface of the refractory layer may be deteriorated.

[0035] The shape of the container is not particularly limited, but may typically be a container with an opening at the top and a circular horizontal cross section. When the horizontal cross section of the container is circular, the container may be a container with a constant inner diameter, i.e., a cylindrical container. Alternatively, the container may be a container with an inner diameter that increases from the bottom to the top (e.g., an inverted truncated cone shape).

[0036] [Crushing tools] In the present invention, at least a part of the refractory layer is crushed by a crushing tool, whereby the deteriorated refractory layer and build-up adhering to the surface of the refractory layer can be removed.

[0037] The crushing tool is not particularly limited, and any tool capable of crushing the refractory layer can be used. Typically, a crushing tool that crushes the refractory layer by applying one or both of a rotational force and an impact force can be used. For example, a hydraulic drifter can be suitably used as the crushing tool.

[0038] In the present invention, when repairing a vessel having a refractory layer on its inner surface as described above, at least a part of the refractory layer is crushed by a crushing tool. Hereinafter, an example of the crushing method of the present invention will be described based on a specific embodiment.

[0039] First Embodiment A method for crushing a refractory layer according to a first embodiment of the present invention includes a first crushing step of crushing at least a part of the refractory layer while moving a crushing tool along a first path, and a second crushing step of crushing at least a part of the refractory layer while moving the crushing tool along a second path. Each of the steps will be described below.

[0040] First crushing process First, in the first crushing step, at least a part of the refractory layer is crushed while moving the crushing tool along the first path. In the present invention, crushing the refractory layer while moving the crushing tool includes not only a mode in which crushing is performed simultaneously while the crushing tool is continuously moved, but also a mode in which crushing is performed while the crushing tool is intermittently moved. Typically, as described in the explanation of FIG. 1, it is preferable to repeatedly perform a series of operations in which the crushing tool is pressed against the refractory layer to crush the refractory layer to a desired depth, then the crushing tool is retreated to a position where it does not contact the remaining refractory layer, and then the crushing tool is moved.

[0041] It is important that the first path, which is the path along which the crushing tool is moved in the first crushing step, is set along the first direction of the inner surface of the container with a gap between the crushing tool areas so that the areas crushed by the crushing tool do not overlap. When crushing the entire container with the crushing tool, the crushing tool movement path is set so that the crushing tool areas overlap to eliminate any uncrushed portions as shown in Fig. 1. In contrast, in the present invention, the crushing tool movement paths are intentionally set with a gap between the crushing tool areas so that the areas crushed by the crushing tool do not overlap.

[0042] The first direction is not particularly limited and may be any direction. From the viewpoint of ease of setting a path, the first direction is preferably an up-down direction (vertical direction) or a left-right direction (horizontal direction). Since the inner surface of an actual container is curved, the left-right direction can be said to be the inner circumferential direction of the container. In addition, when moving the crushing tool in the inner circumferential direction of the container, the crushing tool can be rotated with the horizontal center of the container as the rotation axis. Therefore, the left-right direction can also be said to be the rotation direction.

[0043] In addition, when crushing is performed in the left-right direction in the first crushing step, the refractory layer in the non-crushed area (uncrushed area) between the paths may peel off and fall before the next second crushing step is performed. Since the refractory is a very heavy material, it is dangerous if the refractory with a large area falls. Therefore, it is more preferable that the first direction is the up-down direction.

[0044] Second crushing process Next, in the second crushing step, at least a part of the refractory layer is crushed while moving the crushing tool along a second path. Here, the second paths are set along a second direction intersecting with the first direction on the inner surface of the container, with a gap between them so that the areas crushed by the crushing tool do not overlap. The second direction can be any direction intersecting with the first direction. The angle between the first direction and the second direction is not particularly limited, but from the viewpoint of ease of setting the path, it is preferable that the second direction is a direction perpendicular to the first direction. For example, when the first direction is a vertical direction, it is preferable that the second direction is a horizontal direction.

[0045] When the first and second crushing steps are performed, a region surrounded by the first and second paths where the crushing tool does not pass, that is, a region where crushing is not performed by the crushing step (uncrushed region) is formed. Here, as described above, there is a back crack between the undegraded refractory layer and the deteriorated refractory layer (degraded layer) due to the difference in thermal expansion coefficient. Therefore, by performing crushing so as to surround the periphery, peeling of the refractory layer in the uncrushed region is induced. When peeling occurs starting from the back crack, the deteriorated layer is removed in that portion, and the sound refractory layer is exposed, so that there is no need to remove the refractory layer using a crushing tool. This allows the deteriorated layer on the entire inner surface of the container to be efficiently removed, thereby shortening the time required for repair.

[0046] Fig. 3 is a schematic diagram showing an example of the moving path of the crushing tool in this embodiment, Fig. 3(a) shows the first crushing step, and Fig. 3(b) shows the second crushing step. As in Fig. 1, the target area is a rectangle with a height of 1900 mm and a width of 1200 mm, and the crushing tool used is capable of crushing the refractory layer in a circular area S with a diameter of 200 mm.

[0047] First, at least a part of the refractory layer is crushed while moving a crushing tool along a first path 30 shown in FIG. 3(a). Specifically, crushing is performed while moving the crushing tool at 100 mm intervals from the top to the bottom of the target area. Next, at least a part of the refractory layer is crushed while moving the crushing tool along a second path 40 shown in FIG. 3(b). Specifically, crushing is performed while moving the crushing tool at 100 mm intervals from left to right or right to left of the target area. As a result, crushing is performed in a lattice pattern, and peeling of the refractory layer in the uncrushed area 50 where crushing was not performed is induced.

[0048] In the case shown in Figure 3, 19 x 3 = 57 crushing operations are performed in the first crushing process, and 8 x 4 = 32 crushing operations are performed in the second crushing process. Therefore, the total number of crushing operations is 89, which is a significant reduction from the 154 crushing operations in the case shown in Figure 1.

[0049] The moving pitch (moving distance per time) of the crushing tool in the first crushing step and the second crushing step is not particularly limited, but it is preferable that adjacent crushing regions overlap each other as shown in FIG. 3. For example, when the crushing tool crushes a refractory layer in a circular region, it is preferable that the moving pitch is smaller than the diameter of the region. On the other hand, if the moving pitch is too small, the efficiency decreases. Therefore, it is preferable that the moving pitch is equal to or larger than the radius of the region. It is more preferable that the moving pitch is equal to the radius of the region.

[0050] The intervals 31 between the first paths 30 and the intervals 41 between the second paths 40 are not particularly limited as long as they are spaced apart so that the areas crushed by the crushing tool do not overlap. However, if the refractory layer to be peeled off is huge, the refractory layer may collide with the repair device or the inner surface of the container when it falls, causing damage. Therefore, it is preferable that the intervals 31 and 41 are 2 m or less. On the other hand, if the intervals are too small, the time required for peeling increases. Therefore, it is preferable that the intervals 31 and 41 are 0.3 m or more. Note that the intervals 31 and 41 may be the same or different. The first paths 30 may be equally spaced or not. Similarly, the second paths 40 may be equally spaced or not.

[0051] In the example shown in FIG. 3(a), the crushing tool is always moved from top to bottom. However, from the viewpoint of shortening the moving distance, it is also preferable to alternately reverse the moving direction, such as moving from top to bottom and then from bottom to top.

[0052] Also, while Figure 3 shows an example of crushing and removing the refractory layer in a rectangular area of ​​1900 mm x 1200 mm, the area to be crushed can be set arbitrarily. For example, the entire inner surface of the container can be set as the target area. In that case, for example, if the crushing tool is moved so as to rotate 360° in the inner circumferential direction, it will return to its original position. Therefore, there is no particular need to use a moving path that goes back and forth from side to side as in Figure 3(b), and it may be moved in the same direction.

[0053] Crushing depth When the refractory layer is crushed in the first crushing step and the second crushing step, at least a part of the refractory layer is crushed, and the crushing depth is not particularly limited. Here, the crushing depth refers to the position (depth) in the thickness direction of the refractory layer to which the refractory layer is crushed. However, as described above, the back crack grows near the interface between the deteriorated layer and the sound refractory layer. Therefore, when the refractory layer is crushed by the crushing tool, it is preferable to perform the crushing at least to the interface. In other words, it is preferable to perform the crushing so that the tip of the crushing tool reaches the sound refractory layer beyond the deteriorated layer. In this way, by performing the crushing up to the interface where the grown back crack exists, it is easier to induce peeling of the deteriorated layer starting from the back crack.

[0054] The method of controlling the crushing depth is not particularly limited, and any method may be used. For example, a target crushing depth required to reach a sound refractory layer may be set in advance, and crushing may be performed according to the target crushing depth. For example, the target crushing depth may be determined based on the thickness of the deteriorated layer estimated from the usage history of the container (number of times of use, usage time, etc.) and the measurement results of the three-dimensional shape of the inner surface of the container.

[0055] Second Embodiment As described in the description of the first embodiment, by performing the first and second crushing steps, peeling is induced starting from the back crack, and a part (deteriorated layer) of the refractory layer in the uncrushed region surrounded by the first and second paths is peeled off. In order for such peeling of the uncrushed region to occur, it is desirable that the back crack has grown to a certain extent in the uncrushed region.

[0056] However, the growth state of the back crack varies depending on various conditions such as the usage state of the container, and in some cases, there may be cases where the back crack is not present enough and peeling does not occur in the uncrushed area. In addition, it is difficult to determine in a non-destructive manner (for example, from the appearance or the three-dimensional shape of the surface of the inner surface of the container) whether a grown crack exists in the uncrushed area. Therefore, it is difficult to predict in advance whether peeling will actually occur in each of the multiple uncrushed areas.

[0057] In order to solve this problem, in the second embodiment of the present invention, in addition to the first and second crushing steps in the first embodiment described above, a judgment step and an additional crushing step are further carried out. These steps will be described below. Note that the points not specifically mentioned can be the same as those in the first embodiment.

[0058] ·Judgment process In this embodiment, the refractory layer is crushed or peeled off even in the uncrushed area where no peeling has occurred by performing an additional crushing step described later. In order to perform the additional crushing step, it is necessary to determine whether peeling has occurred in the uncrushed area. Therefore, after the second crushing step, a determination step is performed to determine whether at least a part of the refractory layer (typically a deteriorated layer) has peeled off in the uncrushed area on the inner surface of the container surrounded by the first path and the second path. Note that, when there are multiple uncrushed areas, it is preferable to determine whether peeling has occurred in each of the multiple uncrushed areas in the determination step.

[0059] The method of making the judgment is not particularly limited, and can be any method. For example, the judgment can be made by an operator using visual inspection or an image captured by a camera or the like, or the judgment can be made automatically by analyzing some measurement data or the like. The measurement data used for the judgment is not particularly limited, and examples thereof include image data of the inner surface of the container and three-dimensional shape data of the inner surface of the container. The three-dimensional shape data can be obtained by any method capable of measuring a three-dimensional shape, such as a profile sensor or photogrammetry.

[0060] Additional crushing process After the determination step, an additional crushing step is performed. In the additional crushing step, additional crushing is performed when the refractory layer is not peeled off in the uncrushed area. The additional crushing is performed while moving the crushing tool along a third path that passes through the uncrushed area where it is determined that no peeling has occurred.

[0061] The third path is not particularly limited as long as it passes through an uncrushed region determined to be free of peeling, but is preferably a path set to divide the uncrushed region into two or more regions. The third path may be in a direction (angle) different from either the first path or the second path, but is preferably parallel to either the first path or the second path.

[0062] As described above, by fracturing the refractory layer in the uncrushed region while moving the crushing tool along the third path, peeling of the refractory layer remaining in the uncrushed region without peeling is induced.

[0063] It is also assumed that the uncrushed region may not peel off even after the additional crushing step. In consideration of such a case, the judgment step and the additional crushing step may be repeated two or more times. When the judgment step and the additional crushing step are repeated, the number of times is not particularly limited and can be any number of times. The number of times can be determined in advance, but it is preferable to repeat the process until it is determined that there is no uncrushed region in which peeling has not occurred in the judgment step.

[0064] Fig. 4 is a schematic diagram showing an example of a moving path of the crushing tool in this embodiment. Fig. 4(a) and Fig. 4(b) are diagrams showing a first crushing step and a second crushing step, respectively, and these two steps are basically the same as those in the first embodiment described in Fig. 3. Other conditions are also the same as those in Fig. 3.

[0065] However, in this example, as shown in FIG. 4(b), of the six uncrushed regions 50a to 50f formed after the second crushing step, the refractory layer peeled off in 50a and 50b, but not in the four regions 50c to 50f.

[0066] Therefore, a determination step is first performed to identify the uncrushed regions (50c to 50f) in which the refractory layer has not been peeled off.

[0067] Next, as shown in Fig. 4(c), the refractory layer is crushed while moving the crushing tool along a third path passing through the uncrushed regions (50c to 50f) where the refractory layer has not been peeled off (additional crushing step). In this example, the third path is set parallel to the second path, i.e., in the horizontal direction, and is set so as to equally divide the four uncrushed regions 50c, d, e, and f in the vertical direction.

[0068] Although the judgment step and the additional crushing step are each performed once, in this example, the judgment step is performed a second time. As a result, as shown in FIG. 4(c), it can be seen that the refractory layers (deteriorated layers) in the uncrushed areas 50c2 and 50f1 peeled off in the additional crushing step, but did not peel off in the remaining uncrushed areas.

[0069] Therefore, in order to peel off the refractory layer in the uncrushed area that was not peeled off, a second additional crushing process is performed. In this example, since the vertical width of the uncrushed area that was not peeled off (50c1, etc.) is smaller than the diameter of the crushing tool, the refractory layer is crushed over the entire surface of the uncrushed area in the second additional crushing process. As a result, the refractory layer (deteriorated layer) in the entire area of ​​1900 mm x 1200 mm was removed by crushing or peeling. In this example, as shown in FIG. 4(d), the deteriorated layer in the uncrushed areas 50a, 50b, 50c2, and 50f1 was removed by peeling starting from the back crack without crushing.

[0070] [Reaction support device] In either the first or second embodiment, it is preferable to use a reaction support device when crushing the material, and the case where this reaction support device is used will be described below.

[0071] In order to crush the refractory layer using a crushing tool, it is necessary to press the crushing tool against the refractory layer. At that time, a force (reaction force) in the opposite direction is applied to the crushing tool and a member supporting the crushing tool (hereinafter collectively referred to as the crushing device) due to a reaction. If the crushing device is deformed by this reaction force, the position of the crushing tool will be shifted, and the accuracy of controlling the range (depth) of removing the refractory layer may decrease.

[0072] Therefore, a crushing tool is provided at one end of the crushing device, and a reaction force support device is provided at the other end of the crushing device. When crushing, the crushing tool is pressed against one of the opposing inner surfaces of the container, and the reaction force support device is pressed against the other opposing inner surface. In this way, by supporting the side of the crushing device opposite the crushing tool with the reaction force support device, deformation of the device due to the reaction force and the resulting displacement of the crushing tool can be prevented. As a result, it becomes possible to control the range of the refractory layer to be removed with great accuracy.

[0073] The structure of the reaction force support device is not particularly limited, and any structure can be used as long as it can support the reaction force. When crushing, the tip of the reaction force support device is pressed against the inner surface of the container. At that time, in order to prevent the inner surface of the container that comes into contact with the reaction force support device from being damaged, it is preferable that the tip of the reaction force support device is provided with an abutting member that contacts the inner surface of the container. The abutting member is not particularly limited and any member can be used, but from the viewpoint of reducing the risk of damage to the inner surface of the container, it is preferable that the abutting member is made of a soft material, and more preferably made of an elastic material. As the soft material, it is preferable to use a material selected from, for example, resin and rubber. A combination of multiple soft materials can also be used. As the elastic material, it is preferable to use, for example, rubber. Here, the rubber also includes elastomers.

[0074] The shape of the abutting member is not particularly limited and may be any shape. In one embodiment of the present invention, the abutting member preferably has a flat surface (abutting surface) on the side that comes into contact with the refractory layer. The flat abutting surface can reliably support the reaction force while preventing the force from concentrating at one point on the refractory layer. As the abutting member having a flat abutting surface, for example, a block-shaped or sheet-shaped abutting member can be used. The shape of the abutting surface is not particularly limited either, but can typically be rectangular or circular.

[0075] The shape of the container to be repaired is typically cylindrical or truncated cone, and its horizontal cross section is circular. Therefore, in order to move the crushing tool and the reaction support device along the inner surface of the container, it is preferable that the crushing device is supported rotatably with the horizontal center of the container as the rotation axis. [Explanation of symbols]

[0076] 1 container 10 Refractory layer 11 Surface cracks 12 Infiltration layer 13 Build-up layer 14 Back crack 20 Container body (iron shell) 30 First Route 31 interval 40 Second Path 41 interval 50 Unfractured Area S Area to be crushed by the crushing tool

Claims

1. A method for crushing a refractory layer, comprising the steps of: crushing at least a part of a refractory layer by a crushing tool when repairing a vessel having a refractory layer on an inner surface thereof, the method comprising the steps of: a first crushing step of crushing at least a part of the refractory layer while moving the crushing tool along a first path set at intervals so that regions crushed by the crushing tool do not overlap along a first direction of the inner surface of the container; and a second crushing step of crushing at least a part of the refractory layer while moving the crushing tool along second paths set at intervals from each other along a second direction on the inner surface of the container intersecting with the first direction so that areas crushed by the crushing tool do not overlap.

2. a determination step of determining whether or not at least a part of the refractory layer has peeled off in an uncrushed region of the inner surface of the container, the uncrushed region being surrounded by the first path and the second path after the second crushing step; 2. The method for crushing a refractory layer according to claim 1, further comprising: an additional crushing step of crushing at least a part of the refractory layer in the uncrushed region while moving the crushing tool along a third path passing through the uncrushed region when peeling of the refractory layer does not occur in the uncrushed region.

3. The crushing tool is provided at one end of the crushing device, A reaction support device is provided at the other end of the crushing device, 3. The method for crushing a refractory layer according to claim 1 or 2, wherein, when crushing, the crushing tool is pressed against one of the opposing inner surfaces of the container, and the reaction support device is pressed against the other of the opposing inner surfaces.

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