A frictional seal structure at the head of a rotary kiln

Abstract

The present invention discloses a friction type sealing structure at the kiln head of a rotary kiln, which comprises a cylinder body, a kiln head hood, an air-cooled sleeve, a connecting shell and a friction sealing assembly; a slip ring coaxially arranged with the cylinder body is provided on the air-cooled sleeve; the connecting shell comprises a first cylinder shell and a second cylinder shell. The first cylinder shell is fixedly connected with the kiln head hood and forms a labyrinth buffer structure with the air-cooled sleeve inside. An annular chute with a rectangular cross-section and open outward is formed between the first cylinder shell and the second cylinder shell; the friction sealing assembly comprises a plurality of sector-shaped sliders and a dynamic tensioning mechanism. The plurality of sliders are hermetically and slidably arranged in the annular chute, and the dynamic tensioning mechanism is used to surround the outer periphery of the sliders and radially press the sliders centripetally. The present invention belongs to the field of rotary kiln sealing. Compared with the prior art, the advantages are: strong dynamic sealing performance and convenient for maintenance.

Description

Technical Field

[0001] The invention relates to the technical field of rotary kiln sealing, in particular to a rotary kiln head friction type sealing structure. Background Art

[0002] The rotary kiln is the main equipment for heating bulk materials, and is mostly used in cement, building materials, chemicals, metallurgy, papermaking and other industries. The sealing device is one of the important components of the rotary kiln. The sealing performance of the sealing device has a great impact on whether the process operation of the rotary kiln can be carried out normally. This is because the rotary kiln is operated under negative pressure. If the seal between the kiln head and the kiln head cover is not good, the external cold air will enter the kiln, which will destroy the certain relationship between the amount of material, combustion and air in the kiln, reduce the secondary air volume entering the kiln from the cooler, reduce the secondary air temperature, increase the heat consumption, and increase the forging cost. At the same time, the entry of a large amount of cold air will also increase the load of the exhaust fan and increase the power consumption. In the case of occasional positive pressure, the dust of the kiln head cover will be sprayed out of the kiln head cover through the poorly sealed kiln head seal, causing on-site environmental pollution at the first gear wheel belt. At the same time, the dust falls on the supporting wheel, which will also accelerate the abnormal wear of the wheel belt and the supporting wheel, and reduce the service life of the wheel belt and the supporting wheel.

[0003] The sealing device is required to have good sealing performance to reduce the air leakage to a minimum. Specifically: 1. Adapt to the movement and deformation of the cylinder in all aspects. In view of the fact that the kiln head cover is stationary and the rotary kiln is moving, the kiln body will stretch during the heating process. In normal production, it will move up and down under the action of the hydraulic stopper wheel. At the same time, the overhanging section will also bend and deform and the end face will be deformed (such as the bell mouth). In severe cases, the kiln head cover may even be damaged. Therefore, the sealing device should adapt to the above situation. 2. High temperature resistance, wear resistance, and long service life. In view of the mutual contact and wear of the moving parts and the stationary parts in the sealing device, and the dust, high temperature and difficulty in lubrication, the material of the sealing part is required to be wear-resistant and heat-resistant.

[0004] At present, the sealing structure of the kiln head of the rotary kiln can refer to the attached Figure 1 As shown in the figure, a two-stage fish scale is used to embrace the rotary kiln cylinder, and the wire rope counterweight mainly provides the positive composite sealing force to achieve the effect of dynamic sealing. However, the inventor found that this sealing form has the following disadvantages:

[0005] 1. The fish scales use their own elastic deformation to fit the cylinder, and the scales are stacked on top of each other. Under long-term high temperature and pressure working conditions, wear and deformation will be more serious, so the fit to the cylinder is poor, and it is easy to leak when the cylinder produces axial and radial runout, resulting in poor dynamic sealing;

[0006] 2. The staff cannot directly observe the status of the fish scales (reverse seal), and therefore cannot observe the most important sealing structure. This means that they can only infer the degree of wear of the sealing piece based on the actual working conditions, resulting in remedial measures that can only be taken after the fact, and no advance warning can be given. In addition, the special form of the fish scales also makes their disassembly and maintenance very cumbersome.

[0007] Therefore, the inventor proposes a friction seal structure to solve the problem that poor dynamic seal is inconvenient to repair. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a friction seal structure for a rotary kiln head.

[0009] This design proposes a rotary kiln head friction seal structure, including a cylinder, a kiln head cover, an air cooling sleeve, a connecting shell and a friction seal assembly;

[0010] The air cooling sleeve is fixedly connected to the cylinder and is provided with a slip ring coaxially arranged with the cylinder;

[0011] The connecting shell comprises a first cylinder shell and a second cylinder shell separated from each other, the first cylinder shell is fixedly connected to the kiln head cover and forms a labyrinth buffer structure with the air cooling sleeve inside, the second cylinder shell and the first cylinder shell are coaxially fixedly connected through a connecting piece, and an annular chute with a rectangular cross-section and open to the outside is formed between the first cylinder shell and the second cylinder shell;

[0012] The friction seal assembly includes a plurality of fan-shaped sliders and a dynamic tensioning mechanism. The plurality of sliders are sealingly slidably arranged in the annular slide groove and fit together to form an annular structure. The dynamic tensioning mechanism is used to surround the outer circumference of the slider and radially and centripetally press the slider, so that adjacent sliders and the slider and the slide ring are sealed. The sealing form of the slider and the slide ring can respond quickly under dynamic conditions, and can use friction to stably seal the radial and axial runout of the cylinder. Due to the special installation form of the slider, the friction degree can be observed and replaced independently from the outside of the connection shell.

[0013] Furthermore, the cross-section of the labyrinth buffer structure is an S-shaped bending structure.

[0014] Furthermore, an annular dust baffle is fixedly provided on the inner side of the first cylinder shell, a heat insulation flange is fixedly provided on the air cooling sleeve, and the heat insulation flange and the dust baffle are arranged alternately. The labyrinth buffer structure is used to buffer and prevent dust from falling.

[0015] Furthermore, the rear end of the second cylinder shell is sealed and connected to the cylinder body through an external sealing sheet. This sealing structure can further improve the sealing performance.

[0016] Further, the outer sealing piece is a fish scale piece, and a guard plate for friction with the outer sealing piece is fixedly arranged on the outer periphery of the cylinder body.

[0017] Further, an air duct is communicated in the second cylinder shell, and a fan is communicated with the air duct. The fan is used for cooling the kiln head.

[0018] Further, connecting flanges are arranged at the front end of the second cylinder shell and the rear end of the first cylinder shell, and the connecting piece is a bolt and nut for fixing the distance between the two connecting flanges.

[0019] Further, the inner side of the slip ring is fixedly connected with the cylinder body through a fixing bracket.

[0020] Further, the dynamic tensioning mechanism includes a flexible hoop member surrounding a plurality of sliders and at least one force applying member for providing a pre-tightening force to the flexible hoop member.

[0021] Further, a dust hopper is communicated with the lower side of the first cylinder shell.

[0022] After adopting the above structure, the advantages of the present invention compared with the prior art are as follows:

[0023] 1. The fish scale seal is changed to a slider type seal. The sliders that slide radially are connected to the slip ring. Radial sealing can be carried out through the dynamic tensioning mechanism, and axial sliding can also be carried out between the sliders and the slip ring, so that axial sealing can be realized. The overall dynamic response of the mechanism is rapid and the sealing effect is good.

[0024] 2. The connection form of the first cylinder shell and the second cylinder shell forms an annular chute that exposes the outer periphery of the slider outward. Therefore, the degree of wear of the slider can be directly seen through the annular chute, and the excessively worn slider can be directly replaced, which is convenient for maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a structural diagram of the background technology of a friction seal structure at the kiln head of a rotary kiln according to the present invention.

[0026] Figure 2 is a schematic side sectional view of a friction seal structure at the kiln head of a rotary kiln according to the present invention.

[0027] Figure 3 is a Figure 2 partial enlarged schematic view of part A of a friction seal structure at the kiln head of a rotary kiln according to the present invention.

[0028] Figure 4 is a Figure 2 partial enlarged schematic view of part B of a friction seal structure at the kiln head of a rotary kiln according to the present invention.

[0029] As shown in the figure: 1. Cylinder body, 2. Kiln head hood, 3. Air-cooling sleeve, 4. Connecting shell, 5. Friction seal assembly, 6. Slip ring, 7. First cylinder shell, 8. Second cylinder shell, 9. Labyrinth buffer structure, 10. Connecting piece, 11. Annular chute, 12. Dynamic tensioning mechanism, 13. Slide block, 14. Ash baffle, 15. Heat insulation flange, 16. Outer sealing piece, 17. Guard plate, 18. Fan, 19. Air duct, 20. Connecting flange, 21. Flexible hoop piece, 22. Force applying piece, 23. Ash hopper, 24. Fixed support. Specific implementation mode

[0030] The following is only a preferred embodiment of the present invention, and does not limit the protection scope of the present invention accordingly. The present invention will be further described below with reference to the drawings and embodiments.

[0031] Embodiment 1, see Figure 2-4 as shown:

[0032] This embodiment proposes a friction seal structure for the kiln head of a rotary kiln, including a cylinder body 1, a kiln head hood 2, an air-cooling sleeve 3, a connecting shell 4 and a friction seal assembly 5.

[0033] The cylinder body 1 of the rotary kiln is in an inclined shape with the tail high and the head low. Therefore, the internal materials will move towards the head during the firing process and finally enter the grate cooler. This embodiment is for the seal of the kiln head.

[0034] The cylinder body 1 is driven to rotate by the power part of the rotary kiln, while the kiln head hood 2 is fixedly arranged on the ground and cannot be directly connected to the cylinder body 1. See Figure 2 as shown. A kiln head guard iron is fixedly arranged at the front end of the cylinder body 1, and the kiln head guard iron is fixedly connected to the air-cooling sleeve 3. There is a large gap between the kiln head hood 2 and the kiln head guard iron for collecting ash. Therefore, the friction seal assembly 5 is arranged behind the air-cooling sleeve 3. A fixed support 24 is arranged on the cylinder body 1 behind the air-cooling sleeve 3, and a slip ring 6 is fixed on the fixed support 24. The slip ring 6 is coaxially arranged with the cylinder body 1 and bears the friction in the dynamic seal.

[0035] See Figure 3 as shown. In this solution, the connecting shell 4 includes a mutually separated first cylinder shell 7 and a second cylinder shell 8. The first cylinder shell 7 is fixedly connected to the kiln head hood 2, and the connection part is airtight. The second cylinder shell 8 is fixedly connected to the first cylinder shell 7, and the connection part between the two is used to arrange the friction seal assembly 5. The first cylinder shell 7 is covered on the outside of the air-cooling sleeve 3, and it and the air-cooling sleeve 3 together form a labyrinth buffer structure 9 to buffer the dust-containing gas. Specifically, the cross-section of the labyrinth buffer structure 9 is an S-shaped bending structure. An annular ash baffle 14 is fixedly arranged on the inner side of the first cylinder shell 7, and a heat insulation flange 15 is fixedly arranged on the air-cooling sleeve 3. The heat insulation flange 15 and the ash baffle 14 are arranged alternately.

[0036] The front end face of the second shell 8 and the rear end face of the first shell 7 are both provided with a connecting flange 20, and the two connecting flanges 20 are coaxially fixedly connected by bolt and nut connectors 10. This forms an annular chute 11 with a rectangular cross section and open to the outside between the first shell 7 and the second shell 8.

[0037] See also Figure 3 As shown, the friction seal assembly 5 includes a plurality of fan-shaped sliders 13 and a dynamic tensioning mechanism 12. The slider 13 is fan-shaped and is coaxially arranged with the cylinder 1 in a normal state, which requires that the arc surface on its inner side is arranged in contact with the slip ring 6. And the cross section of the slider 13 is also rectangular, so that it can be sealed and slidably installed in the annular groove 11. For the slider 13, a plurality of sliders 13 can together form an annular structure, and this annular structure can slide in the annular groove 11, which produces a certain dynamic response capability and can cope with the unstable jumping of the cylinder 1. It can be seen from this that the slider 13 and the slip ring 6 will have axial friction with the cylinder 1, while the slider 13 and the annular groove 11 can have radial friction, and the sliders 13 and the sliders 13 can also have a small range of friction. By ensuring the sealing between the above three types of friction, a highly responsive dynamic seal can be achieved.

[0038] As for the material of the slider 13, generally speaking, graphite material is selected. The graphite material has good high temperature resistance and expansion resistance, and it also produces a self-lubricating effect when it wears, and has a good service life and use effect.

[0039] For the pre-tightening of the slider 13, the dynamic tensioning mechanism 12 in this solution surrounds the outer circumference of the slider 13 and presses the slider 13 radially and centripetally, so that the adjacent sliders 13 and the slider 13 and the slip ring 6 are sealed. The dynamic tensioning mechanism 12 includes a flexible clamping member 21 arranged around a plurality of sliders 13 and at least one force-applying member 22 for providing pre-tightening force to the flexible clamping member 21. Specifically, the flexible clamping member 21 uses a steel wire rope, and the force-applying member 22 uses a heavy hammer as a counterweight. This uses gravity as the pre-tightening force, and the steel wire rope always surrounds and tightens the multiple sliders 13, so that the sliders 13 slide centripetally and fit tightly and seal. The sealing form of the above-mentioned slider 13 and the slip ring 6 can respond quickly in dynamic conditions, and the radial and axial runouts of the cylinder 1 can be stably sealed in the form of friction.

[0040] And because the first cylinder shell 7 and the second cylinder shell 8 have an annular chute 11 open to the outside, the sealing performance of the sealing structure can be directly observed from the outside during the operation of the cylinder 1. On the one hand, it is possible to directly observe where smoke and dust appear in the sealing structure (to find wear and leakage in time); on the other hand, when the cylinder 1 is stationary, it is possible to observe the insertion depth of the slider 13 to determine whether there is excessive friction of the module, so as to replace it in time; on the third hand, this form is conducive to directly replacing the excessively worn slider 13 from the annular chute 11, so as to achieve the purpose of convenient maintenance.

[0041] See also Figure 4 The second cylinder shell 8 is connected with an air duct 19, and the air duct 19 is connected with a fan 18. The fan 18 is used to cool the kiln head to protect the kiln head from being damaged by high temperature. And the rear end of the second cylinder shell 8 is sealed and connected with the cylinder body 1 through an outer sealing sheet 16. The outer sealing sheet 16 is a fish scale sheet, and a guard plate 17 for friction with the outer sealing sheet 16 is fixed on the outer periphery of the cylinder body 1. This sealing structure can further improve the sealing performance and serve as an insurance against air leakage.

[0042] In combination with the above description, in this solution, the ash will be concentrated in the gap between the first cylinder shell 7 and the air cooling jacket 3, so an ash hopper 23 is connected to the lower side of the first cylinder shell 7, and the ash hopper 23 is directly connected to the grate cooler. This allows the ash to be guided downward and recovered through the natural rotation of the cylinder 1.

[0043] During the specific operation, the dust-containing gas is ejected outward along the outer circle of the cold air sleeve through the kiln head guard iron under the positive pressure of the kiln head, and first hits the labyrinth buffer structure 9 composed of the ash baffle plate 14 and the heat insulation flange 15. 90% of the particles lose kinetic energy due to the impact, and enter the grate cooler through the ash hopper 23 under the action of gravity. The remaining 10% of the flying sand material continues to move forward and blows to the friction seal assembly 5. The multiple sliders 13 and the slider 13 are sealed so that the wind carrying the material forms an eddy current area in the labyrinth area. The material loses kinetic energy through the impact and finally enters the grate cooler through the ash hopper 23. As for the dynamic changes caused by the radial and axial jumps of the cylinder 1, since the wire rope and the heavy hammer tighten the multiple sliders 13 at all times and the sliders 13 slide radially, the sliders 13 will be attached to the slip ring 6 for jumping and the sliders 13 will be attached to the slip ring 6 for axial movement, which ensures the dynamic response effect and sealing effect.

[0044] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A frictional seal structure at the kiln head of a rotary kiln, comprising a cylinder body (1), a kiln head hood (2) and an air-cooled sleeve (3), characterized in that: It further includes a connecting housing (4) and a friction sealing assembly (5); The air-cooling jacket (3) is fixedly connected to the cylinder body (1), and a slip ring (6) coaxial with the cylinder body (1) is provided thereon; The connecting housing (4) includes a mutually separated first cylinder shell (7) and a second cylinder shell (8). The first cylinder shell (7) is fixedly connected to the kiln head hood (2) and forms a labyrinth buffer structure (9) with the air-cooling jacket (3) inside. The second cylinder shell (8) and the first cylinder shell (7) are coaxially fixedly connected by a connecting member (10), and an annular chute (11) with a rectangular cross-section and open outward is formed between the first cylinder shell (7) and the second cylinder shell (8); The friction sealing assembly (5) includes a plurality of sector-shaped sliders (13) and a dynamic tensioning mechanism (12). The plurality of sliders (13) are hermetically slidably arranged in the annular chute (11) and are mutually attached to form an annular structure. The dynamic tensioning mechanism (12) is used to surround the outer periphery of the sliders (13) and radially press the sliders (13) centripetally, so that the adjacent sliders (13) and between the sliders (13) and the slip ring are hermetically connected; The rear end of the second cylinder shell (8) is hermetically connected to the cylinder body (1) through an outer sealing piece (16); The outer sealing piece (16) is a fish scale shape, and a guard plate (17) for rubbing against the outer sealing piece (16) is fixedly provided on the outer periphery of the cylinder body (1); The inner side of the slip ring (6) is fixedly connected to the cylinder body (1) through a fixed bracket (24); The dynamic tensioning mechanism (12) includes a flexible hoop member (21) surrounding a plurality of sliders (13) and at least one force applying member (22) providing a pre-tightening force for the flexible hoop member (21).

2. The friction seal structure at the head of the rotary kiln according to claim 1, characterized in that: The cross-section of the labyrinth buffer structure (9) is an S-shaped bent structure.

3. A frictional seal structure at the kiln head of a rotary kiln according to claim 2, characterized in that: An annular dust baffle (14) is fixedly provided on the inner side of the first cylinder shell (7), and a heat insulation flange (15) is fixedly provided on the air-cooling jacket (3). The heat insulation flange (15) and the dust baffle (14) are arranged alternately.

4. A frictional sealing structure at the head of a rotary kiln according to claim 1, characterized in that: An air duct (19) is communicated in the second cylinder shell (8), and a blower (18) is communicated with the air duct (19).

5. A frictional sealing structure at the head of a rotary kiln according to claim 1, characterized in that: Connecting flanges (20) are provided at the front end of the second cylinder shell (8) and the rear end of the first cylinder shell (7). The connecting member (10) is a bolt and nut for fixing the distance between the two connecting flanges (20).

6. A frictional seal structure at the head of a rotary kiln according to claim 1, characterized in that: A dust hopper (23) is communicated on the lower side of the first cylinder shell (7).

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