Method for crushing refractory layers

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 at least a part of a refractory layer by a crushing tool when repairing a container having a refractory layer on its inner surface.

Background Art

[0002] In order to hold high-temperature contents, it is common to provide a refractory layer as a lining on the inner surface of a container to protect the container body from the heat of the contents. Examples of such a container having a refractory layer include a container for holding molten metal (hereinafter referred to as a "molten metal container").

[0003] However, when using such a container, the surface layer of the refractory layer gradually deteriorates due to wear caused by contact with high-temperature contents and structural spoiling (cracking, peeling) caused by thermal shock or the like. Therefore, in order to maintain the function of the refractory layer, it is necessary to perform repairs regularly.

[0004] As a method for repairing a refractory layer, a method of spraying refractory castables is generally used. However, when spraying refractory castables onto a deteriorated refractory layer, an interface between the deteriorated refractory layer (hereinafter referred to as a deteriorated layer) and the new refractory layer remains inside the repaired refractory layer. In addition, slag (build-up) such as molten metal and slag attached to the surface of the deteriorated refractory layer may be attached when the container was in use. Therefore, when cracks occur in the new refractory layer on the surface side during use of the repaired container, molten metal or the like may penetrate through the cracks 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 peeling, when repairing a refractory layer, after scraping the surface of the repair location to remove the deteriorated layer and the slag attached to the surface of the refractory layer, spraying refractory castables is performed.

[0006] One method for removing the deteriorated layer is to use large heavy machinery such as hydraulic breakers. However, using such large heavy machinery may damage the shaped refractory material (firebrick) that is installed as a base for the unshaped refractory material.

[0007] Therefore, for example, Patent Document 1 proposes that when repairing the lining of the inner surface of a molten metal container by spraying, the deteriorated layer on the surface of the refractory layer is removed and dismantled over the entire surface in advance using a repair device equipped with crushing tools, rather than the heavy machinery described above. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2006-292278 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] However, since the size of typical crushing tools is about 200 to 300 mm in diameter, attempting to crush and remove the deteriorated layer on the surface of the refractory layer on the inner surface of a molten metal container over its entire surface using a crushing tool, as proposed in Patent Document 1, presented the problem of requiring a long time.

[0010] As an example, we will describe the case of crushing and removing a refractory layer in a rectangular area with a height of 1900 mm and a width of 1200 mm using a crushing tool. Figure 1 is a schematic diagram showing an example of the movement path of a crushing tool when the entire area is crushed by the crushing tool. The crushing tool is assumed to be capable of crushing a refractory layer in a circular area S with a diameter of 200 mm.

[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 location is crushed. Then, the crushing tool is moved 100 mm to the right, and the refractory layer at the new location is crushed. This process is repeated until the crushing tool reaches the right edge of the area. This crushes one layer of refractory material horizontally. In this example, 11 crushing operations are required to crush one layer of refractory material.

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

[0013] Next, move the crushing tool downwards. Specifically, first move the crushing tool 85 mm downwards, perform crushing at that position, and then move the crushing tool 85 mm downwards again.

[0014] Next, the refractory layer at that location is crushed. Then, the crushing tool is moved 100 mm to the left, and the refractory layer is crushed at the new location. The above process is repeated until the crushing tool reaches the left edge of the area.

[0015] By repeating the above process, it is possible to crush almost the entire area by moving the crushing tool back and forth. In this example, 13 stages of crushing are performed in the vertical direction. Therefore, in addition to 11 crushing sessions for 13 stages, 11 more crushing sessions are performed while moving downwards, for a total of 154 crushing sessions. Here, we have given an example of crushing a relatively narrow area of ​​1900mm x 1200mm, but when repairing actual containers, especially molten metal containers used in industry, the entire inner surface of the container may need to be repaired, so crushing the refractory layer will take a considerable amount of time.

[0016] This invention has been made in view of the above circumstances, and aims to provide a method for quickly crushing and removing the deteriorated layer of the refractory material on the inner surface of a container. [Means for solving the problem]

[0017] As a result of their investigation to solve the above problems, the inventors of the present invention have found that by utilizing the back cracks that form as the refractory layer deteriorates, the deteriorated layer can be efficiently removed without having to crush the entire refractory layer on the inner surface of the container.

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

[0019] As shown in Figure 2(a), surface cracks 11 occur on the surface of the refractory layer 10 upon contact with molten metal. Then, as shown in Figure 2(b), a soaking layer 12 is formed on the surface of the refractory layer 10 as molten metal penetrates the surface cracks 11 and grows inward (arrow A). Meanwhile, a build-up layer 13 is formed on the surface of the refractory layer 10 as slag and other debris adheres to it and grows outward (arrow B). In this specification, the layer into which molten metal has penetrated is referred to as the "soaking layer," and the soaking layer and the build-up layer together are referred to as the "deteriorated layer." In other words, the "soaking layer" is included in the "deteriorated layer."

[0020] Eventually, due to the difference in thermal expansion coefficients between the undeteriorated refractory layer 10 and the wetting layer 12, back cracks 14 occur near the interface between the refractory layer 10 and the wetting layer 12, as shown in Figure 2(c). The generated back cracks 14 gradually grow along the interface between the refractory layer 10 and the wetting layer 12, resulting in a condition where delamination is likely to occur at the interface between the undeteriorated refractory layer 10 and the wetting layer 12.

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

[0022] Thus, as the container is used, cracks are formed inside the refractory layer. Therefore, in the container to be repaired, as shown in Figs. 2(c) and (d), there are portions where the infiltration layer is likely to peel off due to the presence of back cracks. In such parts, even if the part itself is not crushed by a crushing tool, peeling may occur by crushing around it so as to surround the part.

[0023] The present invention utilizes the peeling phenomenon caused by the above-described back cracks, and its main configuration is as follows.

[0024] 1. A method for crushing a refractory layer for repairing a container having a refractory layer on its inner surface, wherein at least a part of the refractory layer is crushed by a crushing tool, the method 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 the regions crushed by the crushing tool do not overlap, along a first direction on the inner surface of the container; a second crushing step of crushing at least a part of the refractory layer while moving the crushing tool along a second path set at intervals so that the regions crushed by the crushing tool do not overlap, along a second direction on the inner surface of the container that intersects the first direction.

[0025] 2. A determination step of determining whether at least a part of the refractory layer has peeled off in an uncrushed region surrounded by the first path and the second path on the inner surface of the container after the second crushing step. When the peeling of the refractory layer has not occurred in the uncrushed area, an additional crushing step of crushing at least a part of the refractory layer in the uncrushed area while moving the crushing tool along a third path passing through the uncrushed area, the method for crushing a refractory layer according to 1 above.

[0026] 3. The crushing tool is provided at one end of a crushing device, A reaction force support device is provided at the other end of the crushing device, When performing crushing, the crushing tool is pressed against one surface of the opposing inner surface of the container, and the reaction force support device is pressed against the other surface of the opposing inner surface, the method for crushing a refractory layer according to 1 or 2 above.

Advantages 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 container is crushed along the first path and the second path. As a result, the peeling of the deteriorated layer of the refractory layer in the area surrounded by the first path and the second path is induced, and the deteriorated layer can be removed without crushing the entire refractory layer on the inner surface of the container. And as a result, the time required for repair can be shortened.

Brief Description of the Drawings

[0028] [Figure 1] It is a schematic diagram showing an example of the movement path of the crushing tool when the entire refractory layer is crushed by the crushing tool. [Figure 2] It is a schematic diagram showing the process of forming cracks in the refractory layer. [Figure 3] It is a schematic diagram showing an example of the movement path of the crushing tool in the first embodiment. [Figure 4] It is a schematic diagram showing an example of the movement path of the crushing tool in the second embodiment.

Modes for Carrying Out the Invention

[0029] The present invention will be described in detail below. The following description is an example of a preferred embodiment of the present invention, and the present invention is not limited to the embodiments described below. Furthermore, elements not mentioned herein can be repaired in the same manner as in conventional repair methods.

[0030] [container] The present invention relates to a container having a refractory layer on its inner surface. The container can be any container as long as it has at least a refractory layer on its inner surface. The container may, for example, consist of a metal container body and a refractory layer provided on the inner surface of the container body. The container body is typically made of steel and is also called a steel shell. The refractory layer is also called a lining.

[0031] The container may be, for example, a container for molten metal. Examples of containers for molten metal include a ladle, a ladle for molten steel, and a refining vessel.

[0032] The present invention can be applied to refractory layers 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 composed of refractory material.

[0033] Furthermore, it is common practice to construct the refractory lining layer from a layer of shaped refractory material called permal brick and a layer of unshaped refractory material. For example, a typical molten metal container comprises a metal container body called an iron shell, a layer of shaped refractory material (permal brick) provided on the inner surface of the container body, and a layer of unshaped refractory material provided on the inner surface of the shaped refractory layer, with the refractory layer and the unshaped refractory layer forming the refractory layer. The present invention can also be suitably used for repairing refractory layers having the above-described structure.

[0034] Furthermore, the present invention is intended to break and remove the refractory layer when repairing a container. Therefore, the container may be a used container. Also, the refractory layer may have deteriorated on at least a portion of its surface.

[0035] The shape of the container is not particularly limited, but typically it may be a container with an opening at the top and a circular horizontal cross-section. If the horizontal cross-section of the container is circular, it may be a container with a constant inner diameter, i.e., a cylindrical container. Alternatively, it may be a container with a shape in which the inner diameter increases from the bottom to the top (such as an inverted frustocone shape).

[0036] [Crushing tools] In this invention, at least a portion of the refractory layer is crushed using a crushing tool. This makes it possible to remove deteriorated refractory layers and buildup adhering to the surface of the refractory layer.

[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 rotational force and / or 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 container having a refractory layer on its inner surface as described above, at least a portion of the refractory layer is crushed using a crushing tool. An example of the crushing method in the present invention will be described below based on a specific embodiment.

[0039] (First embodiment) The first embodiment of the present invention provides a method for crushing a refractory layer, comprising: a first crushing step of crushing at least a portion of the refractory layer while moving a crushing tool along a first path; and a second crushing step of crushing at least a portion of the refractory layer while moving the crushing tool along a second path. Each of these steps will be described below.

[0040] • First crushing process First, in the first crushing step, at least a portion of the refractory layer is crushed while moving the crushing tool along the first path. In this invention, crushing the refractory layer while moving the crushing tool includes not only the mode in which crushing is performed simultaneously while continuously moving the crushing tool, but also the mode in which crushing is performed in between intermittent movements of the crushing tool. Typically, as described in the explanation of Figure 1, it is preferable to repeatedly perform a series of operations in which the crushing tool is pressed against the refractory layer to crush it to a desired depth, then the crushing tool is moved back to a position where it does not come into contact with the remaining refractory layer, and then the crushing tool is moved.

[0041] In the first crushing step described above, it is important that the first path, which is the path for moving the crushing tool, is set along the first direction on the inner surface of the container, with gaps between them so that the areas to be crushed by the crushing tool do not overlap. When crushing the entire material with the crushing tool, as shown in Figure 1, the movement path of the crushing tool is set so that the areas to be crushed overlap in order to eliminate any parts that are not crushed. In contrast, in the present invention, the movement paths are intentionally set with gaps between them so that the areas to be 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 the path, the first direction is preferably the up-and-down direction (vertical direction) or the left-and-right direction (horizontal direction). Since the inner surface of an actual container is curved, the left-and-right direction can be said to be the inner circumference direction of the container. Furthermore, when moving the crushing tool in the inner circumference direction of the container, the crushing tool can be rotated with the horizontal center of the container as the axis of rotation. Therefore, the left-and-right direction can also be rephrased as the rotation direction.

[0043] Furthermore, if crushing is performed in the left-right direction during the first crushing step, the refractory layer in the uncrushed areas between the paths (uncrushed areas) may peel off and fall before the second crushing step is carried out. Since refractory materials are very heavy, it is dangerous if large areas of refractory material fall. For this reason, it is more preferable that the first direction is vertical.

[0044] • Second crushing process Next, in the second crushing step, the crushing tool is moved along a second path while crushing at least a portion of the refractory layer. Here, the second path is set along the inner surface of the container, intersecting the first direction, with gaps between them so that the areas crushed by the crushing tool do not overlap. The second direction can be any direction as long as it intersects 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 perpendicular to the first direction. For example, if the first direction is vertical, it is preferable that the second direction is horizontal.

[0045] When crushing is performed using the first and second crushing processes described above, an area is formed that is not passed through by the crushing tool, i.e., an area where crushing is not performed by the crushing process (uncrushed area), enclosed by the first and second paths. As mentioned earlier, there are back cracks between the undeteriorated refractory layer and the deteriorated refractory layer (deteriorated layer) due to the difference in thermal expansion coefficients. Therefore, crushing in a way that surrounds the area induces delamination of the refractory layer in the uncrushed area. When delamination occurs starting from a back crack, the deteriorated layer is removed in that area, and the sound refractory layer is exposed, eliminating the need to remove the refractory layer using the crushing tool. This allows for efficient removal of the deteriorated layer from the entire inner surface of the container, reducing the time required for repair.

[0046] Figure 3 is a schematic diagram showing an example of the movement path of the crushing tool in this embodiment, with Figure 3(a) representing the first crushing process and Figure 3(b) representing the second crushing process. As with Figure 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, the crushing tool is moved along the first path 30 shown in Figure 3(a) to crush at least a portion of the refractory layer. Specifically, the crushing tool is moved at 100 mm intervals from top to bottom of the target area. Next, the crushing tool is moved along the second path 40 shown in Figure 3(b) to crush at least a portion of the refractory layer. Specifically, the crushing tool is moved at 100 mm intervals from left to right or right to left of the target area. As a result, crushing is performed in a grid pattern, and peeling of the refractory layer in the uncrushed areas 50 is induced.

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

[0049] The movement pitch (distance traveled per step) of the crushing tool in the first and second crushing steps is not particularly limited, but it is preferable that adjacent crushing areas overlap, as shown in Figure 3. For example, when the crushing tool crushes a refractory layer in a circular area, it is preferable that the movement pitch be smaller than the diameter of the area. On the other hand, if the movement pitch is excessively small, the efficiency will decrease. Therefore, it is preferable that the movement pitch be greater than or equal to the radius of the area. It is even more preferable that the movement pitch be equal to the radius of the area.

[0050] The spacing 31 between the first paths 30 and the spacing 41 between the second paths 40 are not particularly limited, as long as there is enough space between them so that the areas to be crushed by the crushing tool do not overlap. However, if the refractory layer to be peeled off is large, it may collide with the repair device or the inner surface of the container when it falls, potentially causing damage. For this reason, it is preferable that the spacings 31 and 41 be 2m or less. On the other hand, if the spacing is too small, the time required for peeling will increase. For this reason, it is preferable that the spacings 31 and 41 be 0.3m or more. The spacings 31 and 41 may be the same or different. Also, 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 Figure 3(a), the crushing tool is always moved from top to bottom. However, from the viewpoint of shortening the travel distance, it is also preferable to alternately reverse the direction of movement, such as moving from top to bottom and then from bottom to top.

[0052] Furthermore, 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 arbitrarily set. For example, the entire inner surface of a container can be used as the target area. In that case, for example, if the crushing tool is moved to rotate 360° in the inner circumferential direction, it will return to its original position. Therefore, as shown in Figure 3(b), there is no particular need to have a movement path that goes back and forth from side to side; it may be moved in the same direction.

[0053] • Crushing depth In the first and second crushing steps described above, when crushing the refractory layer, it is sufficient to crush at least a portion of the refractory layer, and the crushing depth is not particularly limited. Here, crushing depth refers to the position (depth) in the thickness direction of the refractory layer to which the refractory layer is crushed. However, as mentioned above, back cracks grow near the interface between the deteriorated layer and the sound refractory layer. Therefore, when crushing the refractory layer with a crushing tool, it is preferable to crush at least up to the interface. That is, it is preferable to crush in such a way that the tip of the crushing tool reaches the sound refractory layer beyond the deteriorated layer. By crushing up to the interface where the grown back crack exists, it becomes easier to induce delamination of the deteriorated layer starting from the back crack.

[0054] The method for controlling the fracturing depth is not particularly limited and can be controlled by any method. For example, a target fracturing depth required to reach a sound refractory layer may be set in advance, and fracturing may be performed accordingly. The target fracturing depth may be determined by estimating the thickness of the deteriorated layer from, for example, the usage history of the container (number of uses, usage time, etc.) or 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 above, the crushing process by the first and second crushing steps induces delamination starting from back cracks, causing a portion of the refractory layer (deteriorated layer) in the uncrushed region enclosed by the first and second paths to peel off. For such peeling of the uncrushed region to occur, it is desirable that back cracks have grown to a certain extent in the uncrushed region.

[0056] However, the growth of back cracks varies depending on various conditions such as how the container is used, so in some cases, delamination of the unbroken areas may not occur because there are not enough back cracks. Furthermore, it is difficult to determine non-destructively (for example, from the appearance or the three-dimensional shape of the inner surface of the container) whether or not grown cracks are present in the unbroken areas. Therefore, it is difficult to predict in advance whether delamination will actually occur in each of the multiple unbroken areas.

[0057] Therefore, in order to solve this problem, in the second embodiment of the present invention, in addition to the first crushing step and the second crushing step in the first embodiment described above, a determination step and an additional crushing step are further performed. These steps will be described below. Unless otherwise specified, the same procedures as in the first embodiment can be followed.

[0058] ·Judgment process In this embodiment, by performing an additional crushing step described later, the refractory layer is crushed or peeled even in the uncrushed areas where peeling did not occur. In order to perform the additional crushing step, it is necessary to determine whether or not peeling has occurred in the uncrushed areas. Therefore, a determination step is performed after the second crushing step to determine whether or not at least a part of the refractory layer (typically the 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. If there are multiple uncrushed areas, it is preferable that the determination step determines whether or not peeling has occurred in each of the multiple uncrushed areas.

[0059] The method of making the determination is not particularly limited and can be done in any way. For example, the determination may be made by an operator using images taken visually or with a camera, or the determination may be made automatically by analyzing some kind of measurement data. The measurement data used for the determination is not particularly limited, but examples include image data of the inner surface of the container or 3D shape data of the inner surface of the container. The 3D shape data can be obtained by any method that can measure 3D shape, such as a profile sensor or photogrammetry.

[0060] • Additional crushing process After the above determination step is performed, an additional crushing step is carried out. In this additional crushing step, additional crushing is performed if peeling of the refractory layer has not occurred in the uncrushed area. The additional crushing is carried out by moving the crushing tool along a third path that passes through the uncrushed area where it has been determined that no peeling has occurred.

[0061] The third path is not particularly limited as long as it passes through an unbroken area where peeling has not occurred, but it is preferable that the path is set to divide the unbroken area into two or more regions. The third path may be in a different direction (angle) from either the first or second path, but it is preferable that it is parallel to either the first or second path.

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

[0063] It is also possible that peeling may not occur in the uncrushed areas even after the above additional crushing process. Therefore, taking such cases into consideration, the judgment process and the additional crushing process may be repeated two or more times. When the judgment process and the additional crushing process are repeated, the number of repetitions is not particularly limited and can be any number. The number of repetitions can be predetermined, but it is preferable to repeat the process until it is determined in the judgment process that there are no uncrushed areas where peeling has not occurred.

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

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

[0066] Therefore, the first step is to perform a determination process to identify the unbroken areas (50c to 50f) where the refractory layer had not peeled off.

[0067] Next, as shown in Figure 4(c), the refractory layer is crushed by moving the crushing tool along a third path that passes through the uncrushed areas (50c to 50f) where delamination of the refractory layer had not occurred (additional crushing step). In this example, the third path is parallel to the second path, i.e., horizontal, and the four uncrushed areas 50c, d, e, and f are divided equally in the vertical direction.

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

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

[0070] [Reaction force support device] In both the first and second embodiments described above, it is preferable to use a reaction force support device when crushing. The following describes the case in which this reaction force support device is used.

[0071] In order to break up the refractory layer using a crushing tool, it is necessary to press the crushing tool against the refractory layer. At that time, the crushing tool and the members that support the crushing tool (hereinafter collectively referred to as the crushing device) will be subjected to a force in the opposite direction (reaction force) due to the reaction force. If the crushing device deforms due to this reaction force, the position of the crushing tool will shift, which may reduce the accuracy of controlling the range (depth) of the refractory layer to be removed.

[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 of the opposing inner surfaces. 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 area from which the refractory layer is removed with extreme precision.

[0073] The structure of the reaction force support device is not particularly limited, and any structure capable of supporting the reaction force can be used. When crushing, the tip of the reaction force support device will be pressed against the inner surface of the container. In this case, to prevent damage to the inner surface of the container that comes into contact with the reaction force support device, it is preferable to provide a contact member at the tip of the reaction force support device that contacts the inner surface of the container. The contact member is not particularly limited, and any material 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 contact member be made of a soft material, and more preferably an elastic material. As the soft material, it is preferable to use a material selected from, for example, resin and rubber. Multiple soft materials can also be used in combination. As the elastic material, it is preferable to use, for example, rubber. Here, rubber also includes elastomers.

[0074] The shape of the contact member is not particularly limited and can be any shape. In one embodiment of the present invention, it is preferable that the surface of the contact member that contacts the refractory layer (contact surface) is flat. By having a flat contact surface, it is possible to reliably support the reaction force while preventing the force from concentrating at one point in the refractory layer. As a contact member with a flat contact surface, for example, a block-shaped or sheet-shaped contact member can be used. The shape of the contact surface is also not particularly limited, but it can typically be rectangular or circular.

[0075] The containers to be repaired are typically cylindrical or truncated cone-shaped, with a circular horizontal cross-section. Therefore, in order to move the crushing tool and reaction force support device along the inner surface of the container, it is preferable that the crushing device is rotatably supported with the horizontal center of the container as the axis of rotation. [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 (metal shell) 30 The first route 31 interval 40 Second Route 41 interval 50 Unbroken Area Area to be crushed by the crushing tool S

Claims

1. A method for crushing a refractory layer, wherein, in repairing a container having a refractory layer on its inner surface, at least a portion of the refractory layer is crushed using a crushing tool, A first crushing step involves crushing at least a portion of the refractory layer while moving the crushing tool along a first path set apart from each other so that the areas to be crushed by the crushing tool do not overlap, along a first direction on the inner surface of the container, The process includes a second crushing step of crushing at least a portion of the refractory layer while moving the crushing tool along a second path set apart from each other along a second direction intersecting the first direction on the inner surface of the container, such that the areas to be crushed by the crushing tool do not overlap. The first direction is the vertical direction, A method for crushing a refractory layer, wherein the movement pitch of the crushing tool in the first crushing step and the second crushing step is set so that adjacent crushing areas overlap.

2. A determination step is performed to determine whether at least a portion of the refractory layer has peeled off in the unbroken region of the inner surface of the container, surrounded by the first path and the second path, after the second crushing step. A method for crushing a refractory layer according to claim 1, further comprising: an additional crushing step of crushing at least a portion of the refractory layer in the uncrushed region while moving the crushing tool along a third path through the uncrushed region, if the refractory layer has not peeled off in the uncrushed region.

3. The crushing tool is provided at one end of the crushing device. A reaction force support device is provided at the other end of the crushing device. A 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 force support device is pressed against the other of the opposing inner surfaces.

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