Wear-resistant cooling section of dry quenching furnace

Abstract

The wear-resistant cooling section of the dry quenching furnace comprises a base layer and a plurality of cooling layers, the base layer is arranged at the bottom, and the cooling layers are sequentially arranged on the base layer; the base layer comprises a plurality of first wear-resistant bricks, all the first wear-resistant bricks are sequentially connected end to end in a closed mode, and any two adjacent first wear-resistant bricks are connected in an engaged mode through an axial groove and an axial groove tongue; the cooling layer comprises a plurality of second wear-resistant bricks, the second wear-resistant bricks are sequentially connected end to end in a closed mode, and any two adjacent second wear-resistant bricks are connected in an engaged mode through axial grooves and axial groove tongues; any adjacent first wear-resistant brick and second wear-resistant brick are meshed and connected through the radial groove and the radial groove tongue; the independent refractory bricks are combined into a whole through the matching of the grooves and the groove tongues, so that the connection strength of the dry quenching furnace is improved; the groove and the groove tongue are matched to form a connecting seam with a U-shaped track between any adjacent refractory bricks, so that the orientation of the connecting seam is changed, coke is prevented from directly impacting the connecting seam, and the connecting seam is prevented from being continuously eroded.

Description

Technical Field

[0001] This application relates to the field of metallurgical equipment technology, specifically to a wear-resistant cooling section for a dry quenching furnace. Background Technology

[0002] A dry quenching furnace (CDQ) is a device that uses inert gas to cool hot coke, primarily used in the coking industry for coke cooling. The main function of the dry quenching furnace is to cool the coke from 1000℃ to below 180℃ through heat exchange between the inert gas and the hot coke, while simultaneously recovering heat for power generation, resulting in significant energy savings and environmental benefits.

[0003] During the fall of coke, the wear-resistant bricks will be worn down due to collisions with the coke. Since the wear resistance of fire mortar is far less than that of refractory bricks, the mortar joints between the bricks are the weak points of wear. As production continues, the difference between the wear at the mortar joints and the wear of the wear-resistant bricks themselves will continue to widen, resulting in dense pits on the wall surface due to uneven wear, thus affecting the connection strength between the wear-resistant bricks. Utility Model Content

[0004] The main objective of this application is to provide a wear-resistant cooling section for a dry quenching furnace, which aims to solve the defect of poor connection strength in the prior art.

[0005] This application achieves the above objectives through the following technical solutions:

[0006] A wear-resistant cooling section for a dry quenching furnace includes:

[0007] The base layer includes a plurality of first wear-resistant bricks; around the axis of the dry quenching furnace, each of the first wear-resistant bricks is connected end to end in sequence, and any two adjacent first wear-resistant bricks are connected by interlocking axial grooves and axial tongues.

[0008] Several cooling layers are arranged sequentially along the axis of the dry quenching furnace. The cooling layer at the bottom is connected to the base layer. Each cooling layer includes several second wear-resistant bricks. Around the axis of the dry quenching furnace, each second wear-resistant brick is connected end to end in sequence. Any two adjacent second wear-resistant bricks are connected by interlocking axial grooves and axial tongues. Any two adjacent first wear-resistant bricks and second wear-resistant bricks are connected by interlocking radial grooves and radial tongues.

[0009] Optionally, the first wear-resistant brick includes a first brick body, and along the height direction of the first brick body, an axial groove is provided on one side of the first brick body, and an axial tongue is provided on the other side.

[0010] Optionally, a radial groove or radial tongue is provided on the top surface of the first brick along the height direction of the first brick.

[0011] Optionally, the second wear-resistant brick includes a second brick body. Along the height direction of the second brick body, an axial groove is provided on one side of the second brick body, and an axial tongue is provided on the other side. A radial groove or radial tongue is provided on the top of the second brick body, and a radial tongue or radial groove is provided on the bottom.

[0012] Optionally, the cooling layer also includes several third wear-resistant bricks. Along the axis of the dry quenching furnace, each of the third wear-resistant bricks is disposed on top of the second wear-resistant bricks. Any adjacent second wear-resistant bricks and third wear-resistant bricks are connected by interlocking radial grooves and radial tongues. Around the axis of the dry quenching furnace, each of the third wear-resistant bricks is sequentially connected end to end. Any two adjacent third wear-resistant bricks are connected by interlocking axial grooves and axial tongues.

[0013] Optionally, the second wear-resistant brick is also provided with a radial limiting groove, and the third wear-resistant brick is provided with a limiting block that is adapted to the limiting groove.

[0014] Optionally, the cooling layer also includes several fourth wear-resistant bricks. Along the axis of the dry quenching furnace, each of the fourth wear-resistant bricks is disposed on top of the third wear-resistant bricks. Any adjacent third wear-resistant bricks and fourth wear-resistant bricks are connected by interlocking radial grooves and radial tongues. Around the axis of the dry quenching furnace, each of the fourth wear-resistant bricks is sequentially connected end to end. Any two adjacent fourth wear-resistant bricks are connected by interlocking axial grooves and axial tongues.

[0015] Optionally, the working surface of the first wear-resistant brick is 0.001%-0.005% of the inner surface of the cooling section of the dry quenching furnace; the working surfaces of the second and third wear-resistant bricks are 0.005%-0.01% of the inner surface of the cooling section of the dry quenching furnace; and the working surface of the fourth wear-resistant brick is 0.001%-0.005% of the inner surface of the cooling section of the dry quenching furnace.

[0016] Optionally, the dry quenching furnace also includes a plurality of first clay bricks and second clay bricks, which are stacked alternately along the axial direction of the dry quenching furnace; and both the first clay bricks and the second clay bricks are disposed behind the second wear-resistant brick or the third wear-resistant brick along the radial direction of the dry quenching furnace.

[0017] Optionally, an expansion joint is provided between any two interlocking axial grooves and axial tongues, and the expansion joints are filled with an elastic expansion body; an elastic expansion body is also filled between any two interlocking radial grooves and radial tongues.

[0018] Compared with the prior art, this application has the following beneficial effects:

[0019] This application includes a base layer and several cooling layers. Along the axial direction of the dry quenching furnace, the base layer is located at the bottom, and each of the cooling layers is sequentially arranged on the base layer. The base layer includes several first wear-resistant bricks. Around the axis of the dry quenching furnace, each of the first wear-resistant bricks is sequentially connected end-to-end, and any two adjacent first wear-resistant bricks are connected by interlocking axial grooves and axial tongues. The cooling layers include several second wear-resistant bricks. Around the axis of the dry quenching furnace, each of the second wear-resistant bricks is sequentially connected end-to-end, and any two adjacent second wear-resistant bricks are connected by interlocking axial grooves and axial tongues. Any adjacent first wear-resistant brick and second wear-resistant brick are connected by interlocking radial grooves and radial tongues.

[0020] This application first achieves interlocking connection within a unified horizontal layer through mutually cooperating axial grooves and axial tongues. Different horizontal layers are then connected through mutually cooperating radial grooves and radial tongues. Compared with the existing fire clay bonding method, the cooperation of the grooves and tongues binds the independent refractory bricks into a whole, maximizing the connection strength of the dry quenching furnace.

[0021] Secondly, the combination of the groove and the tongue will form a U-shaped protrusion between any adjacent refractory bricks, thus complicating the shape of the joint and changing its orientation. This prevents coke from directly impacting the joint, effectively improving the protection of the joint, preventing it from being continuously eroded, and ensuring that the connection strength of the refractory bricks always meets the requirements.

[0022] Finally, because this application can effectively control the erosion at the joints, it can effectively ensure the smoothness of the inner wall of the dry quenching furnace, and ensure the normal falling and discharge of coke. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a wear-resistant cooling section of a dry quenching furnace provided in Embodiment 1 of this application;

[0024] Figure 2 This is a schematic diagram of the structure of the first wear-resistant brick;

[0025] Figure 3 This is a schematic diagram of the structure of the second wear-resistant brick;

[0026] Figure 4 This is a schematic diagram of the structure of the third wear-resistant brick;

[0027] Figure 5 This is a schematic diagram of the structure of the fourth wear-resistant brick;

[0028] Figure 6 This is a schematic diagram of the structure of the fifth wear-resistant brick.

[0029] Reference numerals: 1-First wear-resistant brick, 2-Axial groove, 3-Axial groove tongue, 4-Second wear-resistant brick, 5-Radial groove, 6-Radial groove tongue, 7-Third wear-resistant brick, 8-Limiting groove, 9-Limiting block, 10-Fourth wear-resistant brick, 11-First clay brick, 12-Second clay brick, 13-Expansion joint, 14-Elastic expansion body, 15-Fifth wear-resistant brick.

[0030] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0035] Example 1:

[0036] Reference Figures 1 to 6 This embodiment, as an optional embodiment of this application, discloses a wear-resistant cooling section for a dry quenching furnace, including a base layer and several cooling layers. Along the height direction of the dry quenching furnace, the base layer is located at the bottom of the dry quenching furnace, and each of the cooling layers is stacked sequentially on the base layer along the height direction of the dry quenching furnace.

[0037] It should be noted that the specific number of cooling layers needs to be determined based on the height of the cooling section of the dry quenching furnace and the height of each individual cooling layer.

[0038] The base layer includes a plurality of first wear-resistant bricks 1, each first wear-resistant brick 1 including a first brick body, the first brick body being arranged in a cuboid structure.

[0039] It should be noted that the orientation of all bricks in this application is determined in the following way: along the height of the brick, the top of the brick is the top surface, the bottom of the brick is the bottom surface, the side that forms the inner wall of the dry quenching furnace is the inner side surface, the side directly opposite the inner side surface is the outer side surface, and the remaining two sides are the left side surface or the right side surface, respectively.

[0040] An axial groove 2 is provided on the left side of the first brick body, and an axial groove tongue 3 is provided on its right side; it should be noted that an axial groove 2 can also be provided on the right side of the first brick body, and an axial groove tongue 3 can be provided on its left side.

[0041] Meanwhile, a radial groove 5 or a radial tongue 6 is provided on the top surface of each of the first bricks. Preferably, a radial groove 5 is provided on its top surface.

[0042] Around the axis of the dry quenching furnace, the first wear-resistant bricks 1 located in the base layer are connected end to end in a ring structure. At the same time, in any two adjacent first wear-resistant bricks 1, the axial groove tongue 3 of one first wear-resistant brick 1 is inserted into the axial groove 2 of the other first wear-resistant brick 1, thereby realizing the connection between different first wear-resistant bricks 1. Meanwhile, the connection seam between the first axial groove 2 and the first groove tongue is also filled with an elastic expansion body 14, which is made of ceramic fiber felt.

[0043] Furthermore, each of the cooling layers includes a plurality of second wear-resistant bricks 4, each of the second wear-resistant bricks 4 including a second brick body, and along the height direction of the second brick body, an axial groove 2 is provided on the left side of the second brick body, an axial groove tongue 3 is provided on its right side, a radial groove 5 or a radial groove tongue 6 is provided on the top of the second brick body, and a radial groove tongue 6 or a radial groove 5 is provided on its bottom.

[0044] It should be noted that the radial grooves 5 and radial tongues 6 on the second brick body need to be matched with the first wear-resistant brick 1. That is, since the second wear-resistant brick 4 is placed directly on the top surface of the first wear-resistant brick 1, if the radial grooves 5 are provided at the bottom of the second wear-resistant brick 4, then the radial tongues 6 are provided at the top of the first wear-resistant brick 1.

[0045] Each of the second wear-resistant bricks 4 located in the same cooling layer is sequentially fastened together in the same way as each of the first wear-resistant bricks 1 in the base layer; at the same time, the bottom of each of the second wear-resistant bricks 4 is fastened together with each of the first wear-resistant bricks 1 in the base layer through the cooperation of radial grooves 5 and radial tongues 6.

[0046] It should be noted that the expansion joint 13 between any two adjacent second wear-resistant bricks 4 and the expansion joint 13 between any first wear-resistant brick 1 and second wear-resistant brick 4 are filled with an elastic expansion body 14, which is made of ceramic fiber felt.

[0047] Furthermore, the cooling layer also includes a plurality of third wear-resistant bricks 7 and a plurality of fourth wear-resistant bricks 10, wherein the third wear-resistant brick 7 includes a third brick body, the size of the third brick body is the same as that of the second brick body, each of the third brick bodies has an axial groove 2 on its left side, an axial groove tongue 3 on its right side, a radial groove tongue 6 on its top surface, and a radial groove 5 on its bottom surface.

[0048] Along the axis of the dry quenching furnace, each of the third wear-resistant bricks 7 is disposed on top of the second wear-resistant brick 4, that is, any adjacent second wear-resistant brick 4 and third wear-resistant brick 7 are connected by interlocking radial grooves 5 and radial tongues 6.

[0049] Around the axis of the dry quenching furnace, each of the third wear-resistant bricks 7 is connected end to end in sequence. Any two adjacent third wear-resistant bricks 7 are connected by interlocking axial grooves 2 and axial tongues 3. That is, the connection method between each of the third wear-resistant bricks 7 in the same layer is the same as the connection method between each of the second wear-resistant bricks 4.

[0050] Furthermore, a protruding limiting block 9 is provided on the bottom surface of the third wear-resistant brick 7, and a radial limiting groove 8 is provided on the top of the second wear-resistant brick 4. When splicing, the limiting block 9 is inserted into the radial limiting groove 8, which can further improve the connection strength between the second wear-resistant brick 4 and the third wear-resistant brick 7.

[0051] Each of the fourth wear-resistant bricks 10 includes a fourth brick body. The left side of the fourth brick body is provided with an axial groove 2, the right side of the third brick body is provided with an axial groove tongue 3, the top surface of the fourth brick body is provided with a radial groove tongue 6, and the bottom surface of the fourth brick body is provided with a radial groove 5.

[0052] Along the axis of the dry quenching furnace, each of the fourth wear-resistant bricks 10 is disposed on top of the third wear-resistant brick 7, and any adjacent third wear-resistant brick 7 and fourth wear-resistant brick 10 are connected by interlocking radial grooves 5 and radial tongues 6; around the axis of the dry quenching furnace, each of the fourth wear-resistant bricks 10 is connected end to end in sequence, and any two adjacent fourth wear-resistant bricks 10 are connected by interlocking axial grooves 2 and axial tongues 3.

[0053] It should be noted that a cooling layer is divided into three layers in order from low to high. The bottom layer is constructed by the second wear-resistant brick 4, the middle layer is constructed by the third wear-resistant brick 7, and the top layer is constructed by the fourth wear-resistant brick 10. The cooling section of the entire dry quenching furnace is formed by stacking several cooling layers.

[0054] Meanwhile, due to the height limitation of the cooling section, the cooling layer at the top may be reduced. In this case, a top cooling layer is set at the top. The structure of the top cooling layer is the same as that of the cooling layer, except that the third rotating body and / or the fourth rotating body are removed to adjust the total height of the top cooling layer. At the same time, a fifth wear-resistant brick 15 is also set in the top cooling layer. The height of the fifth wear-resistant brick 15 can be flexibly set as needed. In addition, except that the top surface is flat, the structure of the other surfaces is the same as that of the third wear-resistant brick 7.

[0055] Furthermore, the working surface of the first wear-resistant brick 1 is 0.001%-0.005% of the inner surface of the cooling section of the dry quenching furnace; the working surfaces of the second wear-resistant brick 4 and the third wear-resistant brick 7 are 0.005%-0.01% of the inner surface of the cooling section of the dry quenching furnace; and the working surface of the fourth wear-resistant brick 10 is 0.001%-0.005% of the inner surface of the cooling section of the dry quenching furnace.

[0056] It should be noted that the working surface is the inner surface of each wear-resistant brick;

[0057] Compared with the existing technology, the above technical solution can effectively increase the volume of each wear-resistant brick, that is, replace the small wear-resistant bricks in the existing technology with large wear-resistant bricks. The increase in the working surface of the wear-resistant bricks will directly lead to a reduction in the number and total length of expansion joints 13. That is, for the same dry quenching furnace, the number of expansion joints 13 in the cooling section will be effectively controlled. Since expansion joints 13 are the key areas of collision erosion, controlling the number of expansion joints 13 can effectively reduce the erosion of the cooling section and ensure the smoothness of the surface of the cooling section.

[0058] Secondly, because it effectively improves the corrosion condition of the joints, it can effectively extend the service life of the dry quenching furnace, thereby extending the maintenance cycle, which helps to reduce equipment maintenance costs, while improving equipment operating efficiency and increasing the economic benefits of enterprises.

[0059] Furthermore, the dry quenching furnace also includes a first clay brick 11 and a second clay brick 12. It should be noted that the length of the first wear-resistant brick 1 is the same as the length of the fourth wear-resistant brick 10, the length of the second wear-resistant brick 4 is the same as the length of the third wear-resistant brick 7, and the length of the first wear-resistant brick 1 is 1.5-2 times the length of the second wear-resistant brick 4.

[0060] The above arrangement creates a cavity between the first wear-resistant brick 1 and the fourth wear-resistant brick 10. This cavity is used to place the first clay brick 11 and the second clay brick 12. Along the axial direction of the dry quenching furnace, the first clay brick 11 and the second clay brick 12 are stacked alternately in sequence. At the same time, along the radial direction of the dry quenching furnace, the first clay brick 11 and the second clay brick 12 are both located behind the second wear-resistant brick 4 or the third wear-resistant brick 7.

[0061] It should be noted that the placement order of the first clay brick 11 and the second clay brick 12 in any two adjacent cooling sections is reversed.

[0062] This application first achieves interlocking connection within a unified horizontal layer through mutually cooperating axial grooves and axial tongues. Different horizontal layers are then connected through mutually cooperating radial grooves and radial tongues. Compared with the existing fire clay bonding method, the cooperation of the grooves and tongues binds the independent refractory bricks into a whole, maximizing the connection strength of the dry quenching furnace.

[0063] Secondly, the combination of the groove and the tongue will form a U-shaped protrusion between any adjacent refractory bricks, thus complicating the shape of the joint and changing its orientation. This prevents coke from directly impacting the joint, effectively improving the protection of the joint, preventing it from being continuously eroded, and ensuring that the connection strength of the refractory bricks always meets the requirements.

[0064] Finally, because this application can effectively control the erosion at the joints, it can effectively ensure the smoothness of the inner wall of the dry quenching furnace, and ensure the normal falling and discharge of coke.

[0065] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A wear-resistant cooling section for a dry quenching furnace, characterized in that, include: The base layer includes several first wear-resistant bricks (1); around the axis of the dry quenching furnace, each first wear-resistant brick (1) is connected end to end in sequence, and any two adjacent first wear-resistant bricks (1) are connected by interlocking axial grooves (2) and axial tongues (3). Several cooling layers are arranged sequentially along the axis of the dry quenching furnace. The cooling layer at the bottom is connected to the base layer. The cooling layer includes several second wear-resistant bricks (4). Around the axis of the dry quenching furnace, each second wear-resistant brick (4) is connected end to end in sequence. Any two adjacent second wear-resistant bricks (4) are connected by interlocking axial and axial tongues (3). Any two adjacent first wear-resistant bricks (1) and second wear-resistant bricks (4) are connected by interlocking radial grooves (5) and radial tongues (6).

2. The wear-resistant cooling section of a dry quenching furnace according to claim 1, characterized in that, The first wear-resistant brick (1) includes a first brick body. Along the height direction of the first brick body, an axial groove (2) is provided on one side of the first brick body, and an axial groove tongue (3) is provided on the other side.

3. The wear-resistant cooling section of a dry quenching furnace according to claim 2, characterized in that, A radial groove (5) or a radial tongue (6) is provided on the top surface of the first brick along the height direction of the first brick.

4. The wear-resistant cooling section of a dry quenching furnace according to claim 1, characterized in that, The second wear-resistant brick (4) includes a second brick body. Along the height direction of the second brick body, an axial groove (2) is provided on one side of the second brick body, and an axial tongue (3) is provided on the other side. A radial groove (5) or a radial tongue (6) is provided on the top of the second brick body, and a radial tongue (6) or a radial groove (5) is provided on the bottom.

5. The wear-resistant cooling section of a dry quenching furnace according to claim 4, characterized in that, The cooling layer also includes several third wear-resistant bricks (7). Along the axis of the dry quenching furnace, each of the third wear-resistant bricks (7) is disposed on top of the second wear-resistant brick (4). Any adjacent second wear-resistant brick (4) and third wear-resistant brick (7) are connected by interlocking radial grooves (5) and radial tongues (6). Around the axis of the dry quenching furnace, each of the third wear-resistant bricks (7) is connected end to end in sequence. Any two adjacent third wear-resistant bricks (7) are connected by interlocking axial grooves (2) and axial tongues (3).

6. The wear-resistant cooling section of a dry quenching furnace according to claim 5, characterized in that, The second wear-resistant brick (4) is also provided with a radial limiting groove (8), and the third wear-resistant brick (7) is provided with a limiting block (9) that is adapted to the limiting groove (8).

7. The wear-resistant cooling section of a dry quenching furnace according to claim 5, characterized in that, The cooling layer also includes several fourth wear-resistant bricks (10). Along the axis of the dry quenching furnace, each of the fourth wear-resistant bricks (10) is disposed on top of the third wear-resistant brick (7). Any adjacent third wear-resistant brick (7) and fourth wear-resistant brick (10) are connected by interlocking radial grooves (5) and radial tongues (6). Around the axis of the dry quenching furnace, each of the fourth wear-resistant bricks (10) is connected end to end in sequence. Any two adjacent fourth wear-resistant bricks (10) are connected by interlocking axial grooves (2) and axial tongues (3).

8. The wear-resistant cooling section of a dry quenching furnace according to claim 7, characterized in that, The working surface of the first wear-resistant brick (1) is 0.001%-0.005% of the inner surface of the cooling section of the dry quenching furnace; the working surfaces of the second wear-resistant brick (4) and the third wear-resistant brick (7) are 0.005%-0.01% of the inner surface of the cooling section of the dry quenching furnace; the working surface of the fourth wear-resistant brick (10) is 0.001%-0.005% of the inner surface of the cooling section of the dry quenching furnace.

9. The wear-resistant cooling section of a dry quenching furnace according to claim 7, characterized in that, The dry quenching furnace also includes several first clay bricks (11) and second clay bricks (12). Along the axial direction of the dry quenching furnace, the first clay bricks (11) and the second clay bricks (12) are stacked alternately in sequence. Along the radial direction of the dry quenching furnace, the first clay bricks (11) and the second clay bricks (12) are both disposed behind the second wear-resistant brick (4) or the third wear-resistant brick (7).

10. The wear-resistant cooling section of a dry quenching furnace according to claim 1, characterized in that, An expansion joint (13) is provided between any two interlocking axial grooves (2) and axial tongues (3), and the expansion joints (13) are filled with an elastic expansion body (14); an elastic expansion body (14) is also provided between any two interlocking radial grooves (5) and radial tongues (6).

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