Large rotary kiln cylinder installation method and assembly auxiliary device

Abstract

The present invention relates to a method for installing a large rotary kiln cylinder body and an assembly auxiliary device. In the present invention, the large rotary kiln cylinder body is divided into multiple segmented cylinder bodies, and each segmented cylinder body is composed of multiple sub-cylinder bodies. The assembly of the segmented cylinder bodies is carried out on the ground. The assembled segmented cylinder bodies are moved to a predetermined installation position by a jacking gantry vehicle and a moving bolster and installed. After all the multiple segmented cylinder bodies are installed and connected into one body, the completed large rotary kiln cylinder body is obtained. The splicing of the segmented cylinder bodies in the present invention is completed on the ground. The assembled segmented cylinder bodies are jacked up and moved to a predetermined installation position by a jacking gantry vehicle and a moving bolster, without the need for hoisting by a large crane, with a small amount of welding work at high altitude, small welding deformation and high safety. Only a small crane is involved in the entire construction process and can move flexibly.

Description

Technical Field

[0001] The present invention relates to a construction technology for rotary kilns, and more particularly to a method for installing a large rotary kiln cylinder body and an assembly auxiliary device. Background Art

[0002] For the overall installation of large pellet rotary kilns, multiple large hoisting equipment are required to cooperate for hoisting, resulting in high costs and multiple safety hazards. Due to the large volume and weight of the site and the rotary kiln body, as well as the unsatisfactory hoisting working conditions, the hoisting within the site can only be carried out by the way of large crane lifting. There are many high-altitude operations, a large amount of high-altitude welding, large welding deformation, difficult quality control, and many safety hazards. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for installing a large rotary kiln cylinder body and an assembly auxiliary device to solve the problems of high cost, large construction difficulty and multiple safety hazards during the construction of the existing large rotary kiln cylinder body.

[0004] The present invention is implemented as follows: A method for installing a large rotary kiln cylinder body includes the following steps.

[0005] a. Based on BIM, the rotary kiln cylinder body is split into several segmented cylinder bodies, and each segmented cylinder body is further split into several sub-cylinder bodies, and each sub-cylinder body is prefabricated.

[0006] b. Tracks are arranged on the ground between two rotary kiln piers, and the tracks extend to one side of the rotary kiln installation position. A jacking gantry vehicle is installed on the tracks. Guide rails are respectively arranged on the jacking gantry vehicle and on the top surfaces of the rotary kiln piers. A moving bolster is installed on the guide rails of the jacking gantry vehicle.

[0007] c. The initial position of the jacking gantry vehicle is located on one side of the rotary kiln installation position. On the moving bolster, multiple sub-cylinder bodies are spliced into segmented cylinder bodies. First, the segmented cylinder bodies at both ends are spliced, and finally the segmented cylinder body between the two rotary kiln piers is spliced.

[0008] d. After each segmented cylinder body is spliced on the moving bolster, first move the jacking bolster vehicle along the tracks to between the two rotary kiln piers, and then the jacking bolster vehicle jacks up the moving bolster upward so that the guide rails on the jacking bolster vehicle are aligned with the guide rails on the rotary kiln piers.

[0009] e. The moving bolster carries the segmented cylinder body and moves along the guide rails to a predetermined position, and then the segmented cylinder body is lowered onto the rotary kiln piers and temporarily fixed, and welded to the adjacent segmented cylinder body.

[0010] f. After the last segmented cylinder body is jacked up to a predetermined height by the jacking bolster vehicle, it is welded to the segmented cylinder bodies already installed on the rotary kiln piers at both ends, thereby obtaining a complete rotary kiln cylinder body.

[0011] Before installing the rotary kiln shell, install the idler wheel group fixedly on one rotary kiln pier, and install the gear group and idler wheel group fixedly on the other rotary kiln pier.

[0012] Temporary supports are respectively arranged on the ring cooler structure and grate-kiln structure at both ends for temporarily supporting the segmented shell.

[0013] When moving the jacking gantry car and the moving bolster, they are towed by a crane.

[0014] Meanwhile, the present invention also discloses a large rotary kiln shell assembly auxiliary device for realizing the above-mentioned large rotary kiln shell installation method, including a jacking gantry car and a moving bolster. The jacking gantry car includes a chassis, on which first rollers are arranged, and a top frame is arranged above the chassis. The top frame is connected to the chassis through a plurality of jacking devices. The jacking devices include a plurality of jacking standard sections connected in sequence up and down. A guide rail is arranged on the top frame, and the moving bolster is installed on the guide rail. The moving bolster includes a support frame, which is installed on the guide rail through second rollers. Guide columns and jacks are arranged on the support frame, and a platform frame is arranged at the top of the guide columns and jacks. Adjustable supports are arranged on the platform frame.

[0015] The top frame, the support frame and the platform frame are in an inclined state parallel to each other, and a support wheel is arranged at the lower end of the support frame with a lower height.

[0016] Adjusting holes arranged linearly are respectively arranged on both sides of the platform frame, and both ends of the detachable support are installed in the corresponding adjusting holes through bolts.

[0017] The support frame includes support seats on both sides and a connecting frame detachably connected to the two support seats. The connecting frame is located at both ends of the support seats and is in an inverted U shape. The guide columns and jacks are located on the support seats, and the guide columns and the jacks are detachably connected to the platform frame.

[0018] The top of the adjustable support is provided with an arc surface, and a plurality of rotating wheels are arranged on the adjustable support.

[0019] The present invention relates to a new method for installing the barrel of a large rotary kiln. The original method requires the use of multiple large cranes, and most of the assembly and welding work is completed at high altitude, with a high risk factor. In the present invention, the barrel of the rotary kiln is divided into multiple segmented barrels. The splicing of the segmented barrels is completed on the ground. The assembled segmented barrels are lifted and moved to the predetermined installation position by a lifting platform vehicle and a moving support frame, without the need for hoisting by a large crane. Only the high-altitude welding work is required between adjacent segmented barrels, which greatly reduces the workload of high-altitude welding, thereby reducing welding deformation and improving the safety of the construction process. During the entire construction process, only small and light components such as the sub-barrels need to be lifted by a crane, and the movement of the lifting platform vehicle and the moving support frame needs to be towed. Therefore, a small-sized crane can be selected, and the number of cranes can be reduced to at least one. Even if the on-site space is small, the small crane can move flexibly.

[0020] The large rotary kiln barrel assembly auxiliary device of the present invention includes a lifting platform vehicle and a moving support frame. The lifting platform vehicle can perform the assembly of the segmented barrels, horizontally move the segmented barrels from the assembly area between two rotary kiln piers, and then lift the segmented barrels to the top height of the rotary kiln piers. Then, the moving support frame can move the segmented barrels to the predetermined installation position on the top of the rotary kiln piers. Replacing the large crane with the lifting platform vehicle and the moving support frame has a simple structure and is convenient to use, improving the stability and safety when the segmented barrels move upward. Description of the Drawings

[0021] Figure 1 is the structural diagram of the large rotary kiln barrel assembly auxiliary device of the present invention.

[0022] Figure 2 is the end view of the moving support frame of the present invention.

[0023] Figure 3 is the schematic diagram of the large rotary kiln barrel installation method of the present invention.

[0024] Figure 4 is Figure 3 the A-A view of

[0025] In the figure: 1. Lifting platform vehicle; 2. Moving support frame; 3. Track; 4. Guide rail; 5. Rotary kiln pier; 6. Ring cooler structure; 7. Grate-kiln structure; 8. Temporary support; 9. Segmented barrel; 10. Trolley group; 11. Gear group; 12. Large gear; 13. Tyre; 1-1. Chassis; 1-2. First roller; 1-3. Lifting device; 1-4. Top frame; 2-1. Support frame; 2-1-1. Support seat; 2-1-2. Connecting frame; 2-2. Second roller; 2-3. Jack; 2-4. Guide post; 2-5. Platform frame; 2-6. Adjustable support; 2-7. Rotating wheel; 2-8. Support wheel. Detailed Embodiment

[0026] The present invention relates to a method for installing the barrel of a large rotary kiln, which is realized based on an auxiliary device for assembling the barrel of a large rotary kiln.

[0027] As Figure 1 , Figure 2 shown, the auxiliary device for assembling the barrel of a large rotary kiln includes a jacking platform vehicle 1 and a moving support frame 2. The jacking platform vehicle 1 includes a chassis 1-1, on which two rows of first rollers 1-2 are installed. The first rollers 1-2 are used to contact the track 3 on the ground. Above the chassis 1-1, a top frame 1-4 is provided. The top frame 1-4 is connected to the chassis 1-1 through a number of jacking devices 1-3. The jacking device 1-3 includes a number of jacking standard sections connected in sequence up and down.

[0028] The jacking device 1-3 is a commonly used jacking equipment in grid structure construction. Its lower end is fixed on the chassis 1-1, and its upper end is connected to the top frame 1-4 through a connecting piece with a certain height. The standard sections can be arbitrarily increased or decreased in the middle. All the jacking devices 1-3 are controlled by a synchronous hydraulic system for jacking. Generally, the moving support frame 2 located on the top frame 1-4 has a certain inclination angle, which is the same as the inclination angle of the central axis of the rotary kiln barrel. Therefore, the top frame 1-4 also needs to be in an inclined state. The inclination angle of the top frame 1-4 is adjusted by the difference in the number of jacking standard sections of the jacking devices 1-3 under the two ends of the top frame 1-4 and the height of the connecting piece.

[0029] A guide rail 4 is provided on the top frame 1-4. The length direction of the guide rail 4 is the same as the length direction of the rotary kiln barrel. The moving support frame 2 is installed on the guide rail 4. The moving support frame 2 includes a support frame 2-1, and the support frame 2-1 is installed on the guide rail 4 through second rollers 2-2. A guide post 2-4 and a jack 2-3 are provided on the support frame 2-1. A platform frame 2-5 is provided at the top of the guide post 2-4 and the jack 2-3. An adjustable support 2-6 is provided on the platform frame 2-5.

[0030] The top frame 1-4, the support frame 2-1 and the platform frame 2-5 are in an inclined state parallel to each other. A support wheel 2-8 is provided at the lower end of the support frame 2-1 with a lower height. Because the moving support frame 2 will move towards the lower end under the action of gravity during the jacking process, the moving support frame 2 contacts the side wall of the rotary kiln pier 5 through the support wheel 2-8 at the end, and the movement of the moving support frame 2 in the horizontal direction is restricted by the rotary kiln pier 5.

[0031] A plurality of support wheels 2-8 are arranged in the vertical direction at the end of the support frame 2-1. During the upward jacking of the jacking platform vehicle 1, the moving support frame 2 gradually leaves the rotary kiln pier 5. The plurality of support wheels 2-8 can ensure that the rotary kiln pier 5 provides limit support for the moving support frame 2 before it completely leaves the rotary kiln pier 5.

[0032] Adjusting holes are linearly arranged on both sides of the platform frame 2-5. Both ends of the detachable support are installed in the corresponding adjusting holes through bolts, and the segmented cylinder 9 is supported by multiple detachable supports. The number and position of the detachable supports are determined according to the number of sub-cylinders and the installation position of the segmented cylinder 9. At the same time, the detachable supports should avoid the components already installed on the rotary kiln pier 5 and the tyre 13 and large gear 12 on the segmented cylinder 9.

[0033] The support frame 2-1 includes support seats 2-1-1 on both sides and a connecting frame 2-1-2 detachably connected to the two support seats 2-1-1. The support seats 2-1-1 are strip-shaped, and the two support seats 2-1-1 are connected by the connecting frame 2-1-2. The connecting frame 2-1-2 is located at both ends of the support seats 2-1-1, and the support seats 2-1-1 and the connecting frame 2-1-2 form a complete support frame 2-1. The connecting frame 2-1-2 is in an inverted U shape. The guide posts 2-4 and the jacks 2-3 are located on the support seats 2-1-1, and the guide posts 2-4 and the jacks 2-3 are detachably connected to the platform frame 2-5.

[0034] When moving the sliding tyre support along the guide rail 4, the inverted U-shaped connecting frame 2-1-2 can avoid the idler wheel group 10 or gear group 11 on the rotary kiln pier 5. The jacks 2-3 and the guide posts 2-4 are located on both sides of the support frame 2-1 and can also avoid the idler wheel group 10 and the gear group 11 when moving. At the same time, when the platform frame 2-5 moves up and down, it will not be affected by the support frame 2-1. After the segmented cylinder 9 is moved to the predetermined position, the platform frame 2-5 is lowered by the jacks 2-3, so that the segmented cylinder 9 falls on the idler wheel group 10 or the temporary support 8. After the segmented cylinder 9 is fixed, the platform frame 2-5 and the detachable support need to be disassembled and removed, and reassembled before installing the next segment of the segmented cylinder 9.

[0035] The top of the adjustable support 2-6 is provided with an arc surface, and a number of rotating wheels 2-7 are arranged on the adjustable support 2-6. After the sub-cylinders are placed on the adjustable support 2-6, adjacent two sub-cylinders are welded by rotation to form the segmented cylinder 9. The lower end of the segmented cylinder 9 is located above the arc surface, so as to reduce the height of the segmented cylinder 9 and make it stably placed on the adjustable support 2-6.

[0036] Brake devices are installed on the first roller 1-2 and the second roller 2-2, and the rotation of the rollers can be restricted by the brake devices.

[0037] As Figure 3 、 Figure 4 shown, the installation method of the large rotary kiln cylinder includes the following steps.

[0038] First, based on BIM, the rotary kiln cylinder is split into several segmented cylinders 9, and the length of each segmented cylinder 9 is less than or equal to the distance between two rotary kiln supports 5. Each segmented cylinder 9 is further split into several sub-cylinders, and each sub-cylinder is prefabricated.

[0039] Among them, the rotary kiln cylinder can be split into four segments. The first segment is close to the end of the annular cooler and is directly above the rotary kiln support 5 close to the annular cooler structure 6. A tyre 13 is installed on this segmented cylinder 9, and this tyre 13 is used to cooperate with the idler wheel group 10 on the rotary kiln support 5; the second segment is close to the end of the grate-kiln machine and is above the rotary kiln support 5 close to the grate-kiln machine structure 7; the third segment is behind the second segment and is above the rotary kiln support 5 close to the grate-kiln machine structure 7; the fourth segment is between two rotary kiln supports 5, and its two ends are respectively connected to the first segment and the third segment. Each segment is further divided into multiple sub-cylinders, which can be prefabricated in the factory and transported to the construction site for on-site splicing. Since the quality and volume of the sub-cylinders are relatively small, small cranes can be used for hoisting and moving.

[0040] When splicing the segmented cylinder 9, the tyre 13 or the large gear 12 is installed at the predetermined position of the corresponding segmented cylinder 9.

[0041] Before installing the rotary kiln cylinder, the idler wheel group 10 is fixedly installed on the rotary kiln support 5 at the end close to the annular cooler, and the gear group 11 and the idler wheel group 10 are fixedly installed on the rotary kiln support 5 at the end close to the grate-kiln machine.

[0042] Extension plates are installed between the rotary kiln support 5 and the annular cooler structure 6 and between the rotary kiln support 5 and the grate-kiln machine structure 7 to extend the top surface of the rotary kiln support 5 outward.

[0043] Temporary supports 8 are respectively arranged on the annular cooler structure 6 and the grate-kiln machine structure 7 at both ends for temporarily supporting the segmented cylinder 9.

[0044] Tracks 3 are arranged on the ground between two rotary kiln supports 5, and the tracks 3 extend towards one side of the rotary kiln installation position. A jacking gantry vehicle 1 is installed on the tracks 3, guide rails 4 are respectively arranged on the jacking gantry vehicle 1 and on the top surface of the rotary kiln support 5, and a moving bolster 2 is installed on the guide rail 4 of the jacking gantry vehicle 1.

[0045] When arranging the jacking gantry vehicle 1, the angle of the top frame 1-4 is adjusted according to the inclination angle of the rotary kiln cylinder, and the total height of the two end jacking devices 1-3 is controlled by selecting connectors with appropriate heights and installing different numbers of standard sections, so as to control the inclination angle of the top frame 1-4.

[0046] The track 3 is used to transport the segmented cylinder body 9 from the assembly area to the jacking area. The assembly area is located on the ground on one side of the installation position of the rotary kiln cylinder body, and the prefabricated sub-cylinder bodies are assembled in this area. The jacking area is located in the area between two rotary kiln supports 5. After the segmented cylinder body 9 is jacked up in the jacking area, it can then move towards both ends to reach the predetermined installation position.

[0047] The specific structures of the jacking platform vehicle 1 and the moving support frame 2 are as described above, where the length of the moving support frame 2 vehicle is slightly less than the distance between two rotary kiln supports 5.

[0048] The initial position of the jacking platform vehicle 1 is located on one side of the rotary kiln installation position. On the moving support frame 2, multiple sub-cylinder bodies are spliced into the segmented cylinder body 9. During splicing, adjacent two sub-cylinder bodies are welded into one body by rotation. First, the segmented cylinder bodies 9 at both ends are spliced, and finally, the segmented cylinder body 9 between two rotary kiln supports 5 is spliced.

[0049] When splicing the segmented cylinder body 9, it is spliced in the order of the first segment, the second segment, the third segment, and the fourth segment. After each segment is spliced, it is installed, and after the installation of this segment, the splicing and installation of the next segment are carried out until the entire rotary kiln cylinder body is installed.

[0050] After each segmented cylinder body 9 is spliced on the moving support frame 2, first move the jacking support frame vehicle along the track 3 to the area between two rotary kiln supports 5, and then the jacking support frame vehicle jacks up the moving support frame 2 upward to align the guide rail 4 on the jacking support frame vehicle with the guide rail 4 on the rotary kiln support 5. After the guide rail 4 on the jacking platform vehicle 1 is aligned with the guide rail 4 on the rotary kiln support 5, the moving support frame 2 can smoothly move from the jacking support frame vehicle to the rotary kiln support 5.

[0051] Before jacking, the height of the jacking device 1-3 should be as small as possible to reduce the height of the platform frame 2-5. During jacking, the jacking device 1-3 is simultaneously controlled by the synchronous jacking hydraulic device and the standard sections are synchronously increased to ensure the synchronous stability during the rising process of the top frame 1-4.

[0052] The moving support frame 2 carries the segmented cylinder body 9 and moves along the guide rail 4 to the predetermined position, then lowers the segmented cylinder body 9 onto the rotary kiln support 5 and temporarily fixes it, and welds it to the adjacent segmented cylinder body 9.

[0053] After the first segmented cylinder body 9 is moved to the predetermined installation position by the jacking platform vehicle 1 and the moving support frame 2, it is lowered onto the idler wheel group 10 and the temporary support 8 through the jack 2-3, and then the first segmented cylinder body 9 is temporarily fixed.

[0054] After the second segmented cylinder body 9 is moved to the predetermined installation position by the lifting gantry vehicle 1 and the moving support 2, the segmented cylinder body 9 is lowered onto the roller group 10 and the temporary support 8 through the jack 2-3, and then the second segmented cylinder body 9 is temporarily fixed.

[0055] After the third segmented cylinder body 9 is moved to the predetermined installation position by the lifting gantry vehicle 1 and the moving support 2, the segmented cylinder body 9 is lowered onto the gear group 11 through the jack 2-3, so that the large gear 12 meshes with the gear group 11, and the front end of the third segmented cylinder body 9 is welded to the rear end of the second segmented cylinder body 9.

[0056] After the fourth segmented cylinder body 9 is lifted to the predetermined height by the lifting support vehicle, the two ends are respectively welded to the front end of the first segmented cylinder body 9 and the rear end of the third segmented cylinder body 9, so as to obtain a complete rotary kiln cylinder body.

[0057] When moving the lifting gantry vehicle 1 and the moving support 2, they are towed by a crane. Since it is not necessary to lift the segmented cylinder body 9 by the crane at this time, the small crane used for hoisting the sub-cylinder body before can fully provide the required force. During the movement, temporary fixation and welding of the segmented cylinder body 9, a small crane is used for auxiliary cooperation to ensure the safety of each link. The disassembly, assembly and movement of the high-altitude equipment are all completed by the small crane.

[0058] The installation of the original large rotary kiln cylinder body requires the use of multiple large cranes, and most of the assembly and welding work is completed at high altitude, with a high risk factor. In the present invention, the rotary kiln cylinder body is divided into multiple segmented cylinder bodies 9. The splicing of the segmented cylinder bodies 9 is completed on the ground. The assembled segmented cylinder bodies 9 are lifted and moved to the predetermined installation position by the lifting gantry vehicle 1 and the moving support 2, without the need for hoisting by a large crane. Only the adjacent segmented cylinder bodies 9 need high-altitude welding work, which greatly reduces the workload of high-altitude welding, thereby reducing welding deformation and improving the safety of the construction process. During the whole construction process, only the crane is needed to lift the components with lighter weights such as the sub-cylinder body and tow the movement of the lifting gantry vehicle 1 and the moving support 2. Therefore, a small crane with a smaller volume can be selected, and the number of cranes can be reduced to at least one. Even if the on-site space is small, the small crane can move flexibly.

Claims

1. A method for installing the barrel of a large rotary kiln, characterized in that, it includes the following steps: a. Based on BIM, the barrel of the rotary kiln is split into several segmented barrels, each segmented barrel is split into several sub-barrels, and each sub-barrel is prefabricated; b. Tracks are arranged on the ground between two rotary kiln supports, the tracks extend towards one side of the rotary kiln installation position, a jacking gantry vehicle is installed on the tracks, guide rails are respectively arranged on the jacking gantry vehicle and on the top surface of the rotary kiln support, and a moving bolster is installed on the guide rail of the jacking gantry vehicle; c. The initial position of the jacking gantry vehicle is located on one side of the rotary kiln installation position. On the moving bolster, multiple sub-barrels are spliced into segmented barrels. First, the segmented barrels at both ends are spliced, and finally the segmented barrel between the two rotary kiln supports is spliced; d. After each segmented barrel is spliced on the moving bolster, first move the jacking bolster vehicle along the tracks to between the two rotary kiln supports, and then the jacking bolster vehicle jacks up the moving bolster to align the guide rail on the jacking bolster vehicle with the guide rail on the rotary kiln support; e. The moving bolster carries the segmented barrel and moves along the guide rail to a predetermined position, and then the segmented barrel is lowered onto the rotary kiln support and temporarily fixed, and it is welded to the adjacent segmented barrel; f. After the last segmented barrel is jacked up to a predetermined height by the jacking bolster vehicle, it is welded to the segmented barrels already installed on the rotary kiln supports at both ends, thereby obtaining a complete barrel of the rotary kiln.

2. The method for installing the barrel of a large rotary kiln according to claim 1, characterized in that, before installing the barrel of the rotary kiln, a set of idler wheels is fixedly installed on one rotary kiln support, and a set of gears and a set of idler wheels are fixedly installed on the other rotary kiln support.

3. The method for installing the barrel of a large rotary kiln according to claim 1, characterized in that, temporary supports are respectively arranged on the ring cooler structure and the grate-kiln structure at both ends for temporarily supporting the segmented barrel.

4. The method for installing the barrel of a large rotary kiln according to claim 1, characterized in that, when moving the jacking gantry vehicle and the moving bolster, it is towed by a crane.

5. A large rotary kiln barrel assembly auxiliary device for implementing the method for installing the barrel of a large rotary kiln according to claim 1, characterized in that, it includes a jacking gantry vehicle and a moving bolster. The jacking gantry vehicle includes a chassis, on which a first roller is arranged, a top frame is arranged above the chassis, the top frame is connected to the chassis through a number of jacking devices. The jacking device includes a number of jacking standard sections connected in sequence up and down. A guide rail is arranged on the top frame, and the moving bolster is installed on the guide rail. The moving bolster includes a support frame, the support frame is installed on the guide rail through a second roller, guide columns and jacks are arranged on the support frame, a platform frame is arranged at the top of the guide columns and the jacks, and an adjustable support is arranged on the platform frame.

6. The large rotary kiln barrel assembly auxiliary device according to claim 5, characterized in that, the top frame, the support frame and the platform frame are in an inclined state parallel to each other, and a support wheel is arranged at the lower end of the support frame with a lower height.

7. The large rotary kiln cylinder assembly auxiliary device according to claim 5, characterized in that, adjusting holes arranged linearly are respectively provided on both sides of the platform frame, and both ends of the detachable support are installed in the corresponding adjusting holes through bolts.

8. The large rotary kiln cylinder assembly auxiliary device according to claim 5, characterized in that, the support frame includes support seats on both sides and a connecting frame detachably connected to the two support seats. The connecting frame is located at both ends of the support seats, and the connecting frame is in an inverted U shape. The guide posts and the jacks are located on the support seats, and the guide posts and the jacks are detachably connected to the platform frame.

9. The large rotary kiln cylinder assembly auxiliary device according to claim 5, characterized in that, the top of the adjustable support is provided with an arc-shaped surface, and a plurality of rotating wheels are arranged on the adjustable support.

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