Sealing structure of coal mill shell and coal mill

Abstract

The application discloses a sealing structure of a coal mill shell and the coal mill. The coal mill shell is provided with an opening for a rocker arm to pass into the inside of the coal mill shell. The sealing structure comprises: a vertical sealing assembly, which is a first sealing plate arranged above the rocker arm and fixedly connected with the coal mill shell, and a preset vertical gap being formed between the first sealing plate and the rocker arm; and a horizontal sealing assembly, which comprises a hinge and a second sealing plate. The two ends of the hinge in the length direction are connected with the coal mill shell, and the second sealing plate is arranged on the movable end of the hinge and can rotate freely on the outside of the rocker arm along with the swing of the rocker arm. The sealing structure of the coal mill shell can effectively prevent the coal powder from entering the area between the coal mill shell and the rocker arm, ensure the smoothness of the sealing gas passage, prevent the coal mill shell from being deformed and leaking coal due to the poor sealing gas, and thus prolong the operation period of the coal mill, reduce the maintenance cost and improve the working environment while ensuring the long-period reliable operation of the sealing structure.

Description

Technical Field

[0001] This application generally relates to the field of coal mill technology. More specifically, this application relates to a sealing structure for a coal mill housing and a coal mill. Background Technology

[0002] In a vertical coal mill, the grinding rollers are mounted inside the casing via rocker arms. To achieve the grinding action of the rollers, one end of the rocker arm passes through an opening in the side wall of the casing and connects to an external drive mechanism. During operation, the rocker arm needs to swing up and down relative to the casing. To prevent coal dust from leaking out of the rocker arm, a sealing structure is usually installed at this location.

[0003] In existing technologies, rubber plates are often used for sealing between the coal mill casing and the rocker arm. Specifically, the rubber plate is fastened to the casing and the rocker arm with bolts, and the elastic deformation of the rubber plate conforms to the surface of the rocker arm to achieve a seal.

[0004] However, the aforementioned sealing method using rubber plates has the following drawbacks: First, the internal temperature of the coal mill is high during operation. Prolonged use under high temperatures accelerates the aging of the rubber plates, causing them to harden and become brittle, thus reducing their sealing performance. Second, the seal between the rubber plate and the rocker arm is a contact seal; the rocker arm continuously rubs against the rubber plate during its lifting and oscillating motion, leading to severe wear and a gradual increase in the sealing gap. Furthermore, the rubber plates are fastened with bolts. During rocker arm oscillation, the rubber plates are subjected to repeated stretching and bending, making them prone to fatigue fracture at the bolt connections, resulting in seal failure. These problems allow coal dust to easily enter the gap between the casing and the rocker arm from the seal failure point. Accumulation of this dust blocks the sealing air passage, causing pressure imbalance inside the casing, which in turn leads to uneven stress on the casing wall and deformation, ultimately resulting in coal leakage.

[0005] In view of this, there is an urgent need to provide a sealing structure for the coal mill casing and a coal mill solution, so as to effectively prevent coal dust from entering between the casing and the rocker arm while ensuring the long-term reliable operation of the sealing structure, thereby extending the operating cycle of the coal mill, reducing maintenance costs and improving the working environment. Summary of the Invention

[0006] In order to at least solve one or more of the technical problems mentioned above, this application proposes a sealing structure for the coal mill casing and a coal mill solution in several aspects.

[0007] In a first aspect, this application provides a sealing structure for a coal mill housing, the housing having an opening for a rocker arm to pass through it, the sealing structure comprising: a vertical sealing assembly, which is a first sealing plate disposed above the rocker arm and fixedly connected to the housing, the first sealing plate having a preset vertical gap with the rocker arm; and a horizontal sealing assembly, which includes a hinge and a second sealing plate, the hinge having both ends connected to the housing in the length direction, the second sealing plate being disposed at the movable end of the hinge and being able to freely rotate and conform to the outer side of the rocker arm as the rocker arm swings.

[0008] In some embodiments, the hinge includes a fixed pivot and a rotating sleeve fitted around the outer periphery of the fixed pivot. The rotating sleeve can rotate freely around the fixed pivot, and the second sealing plate is fixedly disposed on the outer wall of the rotating sleeve.

[0009] In some embodiments, the rotating sleeve is composed of several sleeve segments, each sleeve segment being fitted onto the outer periphery of the fixed rotating shaft, and each sleeve segment rotating freely around the fixed rotating shaft independently of each other.

[0010] In some embodiments, the upper end of the first sealing plate is connected to the housing wall at the housing opening, and the lower end extends obliquely away from the housing.

[0011] In some embodiments, the fixed rotating shaft is a steel bar with a nominal diameter of 25 mm, and the rotating sleeve is a steel pipe with a nominal diameter of 32 mm.

[0012] In some embodiments, the wall thickness of the rotating sleeve is 10 mm.

[0013] In some embodiments, the first sealing plate is a wear-resistant steel plate, and the Brinell hardness of the wear-resistant steel plate is not less than 500.

[0014] In some embodiments, the wear-resistant steel plate has a thickness of 14 mm.

[0015] In some embodiments, the preset vertical gap is 3-5 mm.

[0016] In a second aspect, this application provides a coal mill, including a housing, a rocker arm, and a sealing structure for the coal mill housing as described above.

[0017] Through the sealing structure of the coal mill casing provided above, the embodiments of this application, through the coordinated cooperation of the vertical sealing component and the horizontal sealing component, can effectively prevent coal dust from entering the area between the casing and the rocker arm, ensure unobstructed sealing gas passage, and prevent the casing from deforming and leaking coal due to poor sealing gas flow. Thus, while ensuring the long-term reliable operation of the sealing structure, it can extend the operating cycle of the coal mill, reduce maintenance costs, and improve the working environment. Attached Figure Description

[0018] The above features of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0019] Figure 1 A front view of the opening and sealing structure on the housing according to an embodiment of this application is shown; Figure 2 A cross-sectional view of a transverse sealing assembly according to an embodiment of this application is shown.

[0020] 1. Housing; 2. Opening; 3. First sealing plate; 4. Lateral sealing assembly; 5. Rocker arm; 41. Fixed rotating shaft; 42. Sleeve section; 43. Second sealing plate. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] It should be understood that the terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terminology used herein is for describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0024] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0025] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0026] like Figure 1 As shown, in some embodiments, this application provides a sealing structure for a coal mill housing, wherein the housing has an opening 2 for a rocker arm 5 to pass through it, and the sealing structure includes: a vertical sealing component, which is a first sealing plate 3 disposed above the rocker arm 5 and fixedly connected to the housing, the first sealing plate 3 having a preset vertical gap with the rocker arm 5; and a horizontal sealing component 4, which includes a hinge and a second sealing plate 43, the two ends of the hinge being connected to the housing in the length direction, the second sealing plate 43 being disposed at the movable end of the hinge and being able to freely rotate and fit against the outside of the rocker arm 5 as the rocker arm 5 swings.

[0027] In this application, the coal mill is a vertical coal mill, with an opening 2 on the casing for the rocker arm 5 to pass through. The sealing structure of the coal mill casing includes a vertical sealing assembly and a horizontal sealing assembly 4. The vertical sealing assembly is a first sealing plate 3 located above the rocker arm 5 and fixedly connected to the casing. The first sealing plate 3 has a preset vertical gap with the rocker arm 5. This vertical gap prevents the first sealing plate 3 from directly contacting the rocker arm 5 during its swing, thus avoiding wear due to friction. At the same time, the vertical gap can block the path of coal dust entering between the casing and the rocker arm 5, preventing coal dust from accumulating in the sealing area.

[0028] The transverse sealing assembly 4 includes a hinge and a second sealing plate 43. The two ends of the hinge in the length direction are connected to the housing. The second sealing plate 43 is disposed at the movable end of the hinge. The second sealing plate 43 can rotate freely and fit against the outside of the rocker arm 5 as the rocker arm 5 swings, so that the second sealing plate 43 can always fit against the outside of the rocker arm 5 during the entire process of the rocker arm 5's lifting and swinging, thereby achieving real-time sealing of the dynamic gap between the housing and the rocker arm 5.

[0029] The sealing structure of the coal mill casing of this application, through the coordinated cooperation of the vertical sealing component and the horizontal sealing component 4, can effectively prevent coal dust from entering the area between the casing and the rocker arm 5, ensure unobstructed sealing gas passage, and prevent the casing from deforming and leaking coal due to poor sealing gas flow. Thus, while ensuring the long-term reliable operation of the sealing structure, it can also extend the operating cycle of the coal mill, reduce maintenance costs, and improve the working environment.

[0030] In one specific implementation, the hinge includes a fixed pivot 41 and a rotating sleeve fitted around the outer periphery of the fixed pivot 41. The rotating sleeve can rotate freely around the fixed pivot 41, and the second sealing plate 43 is fixedly disposed on the outer wall of the rotating sleeve.

[0031] In this application, the hinge includes a fixed pivot 41 and a rotating sleeve fitted around the fixed pivot 41. The rotating sleeve can rotate freely around the fixed pivot 41, and a second sealing plate 43 is fixedly disposed on the outer wall of the rotating sleeve. Specifically, the fixed pivot 41, as the central component of the hinge, has its two ends fixedly connected to the housing in the longitudinal direction and remains stationary in the working state. The rotating sleeve is fitted around the fixed pivot 41 and forms a clearance fit with the fixed pivot 41, allowing the rotating sleeve to rotate flexibly around the fixed pivot 41. The second sealing plate 43 is fixedly connected to the outer wall of the rotating sleeve, thus forming the movable end of the hinge. When the rocker arm 5 swings, the outer side of the rocker arm 5 contacts and pushes the second sealing plate 43. The second sealing plate 43 drives the rotating sleeve to rotate freely around the fixed pivot 41, so that the second sealing plate 43 can automatically adjust its angle with the swing of the rocker arm 5, always fitting against the outer side of the rocker arm 5, achieving real-time sealing of the dynamic gap between the housing and the rocker arm 5.

[0032] like Figure 2 As shown, in a specific embodiment, the rotating sleeve is composed of several sleeve segments 42, each sleeve segment 42 being fitted onto the outer periphery of the fixed rotating shaft 41, and each sleeve segment 42 rotating freely around the fixed rotating shaft 41 independently.

[0033] In the scheme of this application, the rotating sleeve is composed of several sleeve segments 42, each sleeve segment 42 is respectively fitted onto the outer periphery of the fixed rotating shaft 41, and each sleeve segment 42 rotates freely around the fixed rotating shaft 41 independently.

[0034] The solution of this application sets the rotating sleeve into several independent sleeve segments 42, rather than a single long sleeve, so that each sleeve segment 42 can rotate independently around the fixed rotating shaft 41 without interfering with each other. When the rocker arm 5 swings, the second sealing plate 43 drives each sleeve segment 42 to rotate under the pushing action of the rocker arm 5. Since each sleeve segment 42 is independent, each sleeve segment 42 can independently adjust its rotation angle according to the actual force on its position, thereby avoiding jamming between the sleeve and the fixed rotating shaft 41 due to installation errors, welding deformation, or slight twisting when the rocker arm 5 swings. This ensures that the second sealing plate 43 can always move flexibly and fit tightly against the outside of the rocker arm 5 throughout the entire swinging process of the rocker arm 5.

[0035] In one specific implementation, each of the sleeve segments 42 is welded to a corresponding section of the second sealing plate 43, and the sleeve segments 42 are arranged at intervals along the length direction of the second sealing plate 43.

[0036] In the scheme of this application, each sleeve segment 42 is welded to a corresponding section of the second sealing plate 43, and the sleeve segments 42 are arranged at intervals along the length of the second sealing plate 43. Specifically, each sleeve segment 42 is welded and fixed to a section of the second sealing plate 43 corresponding to its position, that is, each sleeve segment 42 is welded to a local area of ​​the second sealing plate 43, rather than welding a whole sleeve to the entire second sealing plate 43; at the same time, the sleeve segments 42 are arranged at intervals along the length of the second sealing plate 43, with gaps between adjacent sleeve segments 42.

[0037] The solution proposed in this application, through the aforementioned segmented welding and spaced arrangement, achieves the following: Firstly, the weld between each sleeve segment 42 and the second sealing plate 43 is relatively short, which effectively reduces the heat input and welding stress generated during the welding process. This avoids bending deformation of the second sealing plate 43 and sleeve due to continuous welding, ensuring that the inner hole of each sleeve segment 42 remains regular, thereby guaranteeing its flexibility to rotate freely around the fixed rotating shaft 41. Secondly, the gap between adjacent sleeve segments 42 can serve as a buffer space to accommodate trace amounts of coal dust during equipment operation. Even if a small amount of coal dust enters between the sleeve and the fixed rotating shaft 41, it can be discharged from the gap or blown away by the sealing gas, preventing the coal dust from accumulating along the axial direction over a long distance and causing jamming between the sleeve and the fixed rotating shaft 41.

[0038] In one specific implementation, the fixed rotating shaft 41 is a steel bar with a nominal diameter of 25mm, and the rotating sleeve is a steel pipe with a nominal diameter of 32mm. The wall thickness of the rotating sleeve is 10mm.

[0039] In this application, the fixed rotating shaft 41 is a steel bar with a nominal diameter of 25mm, and the rotating sleeve is a steel pipe with a nominal diameter of 33mm and a wall thickness of 10mm. It is worth noting that the nominal diameter is a nominal dimension used to identify the specifications of pipes and steel bars, not an accurate actual measurement value. Its purpose is to standardize the specification designations of components, facilitating engineering selection and assembly. Specifically, in this application, the steel bar with a nominal diameter of 25mm serves as the fixed rotating shaft 41, possessing sufficient structural strength to withstand the load transmitted by the second sealing plate 43 during its movement. The steel pipe with a nominal diameter of 33mm and a wall thickness of 10mm serves as the rotating sleeve, fitted around the outer circumference of the steel bar. Its actual inner diameter is approximately 22mm (calculated by subtracting twice the wall thickness from the actual outer diameter corresponding to the nominal diameter), forming an appropriate clearance fit with the outer diameter of the steel bar. This ensures that the rotating sleeve can rotate freely and flexibly around the fixed rotating shaft 41, while preventing excessive shaking of the second sealing plate 43 during operation due to excessive clearance, which would affect the sealing effect.

[0040] Meanwhile, the 10 mm wall thickness gives the steel pipe high structural rigidity and wear resistance margin, which can maintain the dimensional accuracy and shape regularity of the inner hole of the sleeve during long-term operation of the coal mill. It is not easy to deform excessively due to stress or slight wear, thus ensuring the rotational flexibility and sealing reliability of the hinge mechanism during long-term operation.

[0041] In one specific implementation, the first sealing plate 3 is a wear-resistant steel plate with a Brinell hardness of not less than 500. The thickness of the wear-resistant steel plate is 14 mm.

[0042] In this application, the first sealing plate 3 is a wear-resistant steel plate with a Brinell hardness of not less than 500 and a thickness of 14 mm. Those skilled in the art will understand that Brinell hardness is an important hardness indicator characterizing a material's resistance to localized surface indentation deformation. A Brinell hardness of not less than 500 means that the wear-resistant steel plate has extremely high surface hardness, and its wear resistance is far superior to that of ordinary structural steel plates. During the operation of the coal mill, coal powder and coal lumps scour the surface of the first sealing plate 3 at a certain speed. If the hardness of the first sealing plate 3 is insufficient, the surface will rapidly wear and thin, causing the vertical gap between the first sealing plate 3 and the rocker arm 5 to gradually increase, ultimately leading to seal failure.

[0043] The wear-resistant steel plate with a Brinell hardness of not less than 500 can effectively resist the long-term erosion and abrasive wear of pulverized coal. Even under high-speed pulverized coal airflow and particle impact, it can maintain surface flatness and dimensional stability, thus ensuring that the vertical gap between the first sealing plate 3 and the rocker arm 5 remains within the design range during long-term operation. At the same time, the 14mm thickness provides the first sealing plate 3 with sufficient structural thickness margin, giving it adequate bending stiffness and deformation resistance when subjected to pulverized coal impact and internal air pressure. This prevents warping or deformation during operation due to insufficient thickness, ensuring that the first sealing plate 3 can maintain its designed shape and sealing function over a long period.

[0044] In one specific implementation, the wear-resistant steel plate is inclined. Specifically, the upper end of the first sealing plate 3 is connected to the wall of the housing 1 at the housing opening 2, and the lower end extends inclined away from the housing 1. Through the above-mentioned inclined arrangement, the inner surface of the first sealing plate 3 forms a guide slope adapted to the swing trajectory of the rocker arm 5. This can effectively avoid the movement path of the rocker arm 5 during the lifting and swinging process, preventing interference between the rocker arm 5 and the first sealing plate 3. It can also guide the coal dust that impacts or slides onto the surface of the first sealing plate 3 back to the inside of the coal mill along the inclined surface, preventing the coal dust from accumulating at the root of the first sealing plate 3 or the edge of the housing opening 2, thereby ensuring the long-term unobstructed vertical gap between the first sealing plate 3 and the rocker arm 5 and the long-term stability of the sealing effect.

[0045] In some implementations, the preset vertical gap is 3-5 mm.

[0046] In this application, the preset vertical gap is three to five millimeters. This vertical gap refers to the vertical distance between the lower surface of the first sealing plate 3 of the vertical sealing assembly and the upper surface of the rocker arm 5. Setting the vertical gap to three to five millimeters is an optimal range determined based on the actual operating conditions of the coal mill and the processing and assembly precision. On the one hand, this gap size is much smaller than the conventional aggregate particle size of coal powder in the coal mill, which can effectively block the smooth path of coal powder particles between the first sealing plate 3 and the rocker arm 5, and prevent a large amount of coal powder from entering the area between the casing and the rocker arm 5 through this gap; on the other hand, this gap provides a sufficient safety distance between the first sealing plate 3 and the rocker arm 5, ensuring that the rocker arm 5 will not directly contact or rub against the upper first sealing plate 3 during the lifting and swinging process, thereby avoiding damage to the first sealing plate 3 due to mechanical collision, and also avoiding interference of the first sealing plate 3 with the movement of the rocker arm 5. If the vertical gap is too small, the rocker arm 5 may scrape against the first sealing plate 3 due to installation errors or thermal expansion when it swings. In addition, a small gap is not conducive to the formation of a stable air curtain in the gap, and the sealing effect will decrease.

[0047] Those skilled in the art will understand that if the vertical gap is too large, pulverized coal can easily flow in through the gap and accumulate between the first sealing plate 3 and the rocker arm 5. Therefore, a vertical gap of three to five millimeters can effectively block the entry of pulverized coal while ensuring that the rocker arm 5 has unrestricted freedom of movement. This, combined with the sealing gas forming a stable air curtain barrier within the gap area, ensures that the casing sealing gas depressurization zone remains inside the coal mill for extended periods, thereby guaranteeing the stability and reliability of the sealing structure during long-term operation.

[0048] In some embodiments, this application provides a coal mill, including a housing, a rocker arm 5, and a sealing structure for the coal mill housing as described above.

[0049] In this application, the coal mill includes a casing, a rocker arm 5, and a sealing structure for the casing as described above. The casing, as the main load-bearing component of the coal mill, has an opening 2 on its side wall for the rocker arm 5 to pass through. One end of the rocker arm 5 extends into the casing through the opening 2 and connects to the grinding roller, while the other end is located outside the casing and connected to the drive mechanism. Under the action of the drive mechanism, the rocker arm 5 can swing up and down relative to the casing to drive the grinding roller to grind the material inside the casing.

[0050] The sealing structure is located between the housing and the rocker arm 5. Vertical and horizontal sealing components 4 work together from different directions to seal the area where the rocker arm 5 protrudes from the housing. During mill operation, the vertical gap between the first sealing plate 3 of the vertical sealing component and the rocker arm 5 prevents coal dust from entering between the housing and the rocker arm 5. Meanwhile, the second sealing plate 43 of the horizontal sealing component 4 continuously adheres to the outside of the rocker arm 5 as it swings, sealing any dynamic gaps generated during the swing. This coordinated action effectively prevents coal dust leakage to the outside of the housing, ensures unobstructed sealing gas passages, avoids housing deformation and coal leakage, thereby extending the continuous operating time of the mill, reducing maintenance costs, and improving the working environment.

[0051] While numerous embodiments of this application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise for those skilled in the art without departing from the spirit and intent of this application. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A sealing structure for a coal mill casing, wherein the casing has an opening for a rocker arm to pass through it, characterized in that, The sealing structure includes: A vertical sealing assembly, comprising a first sealing plate disposed above the rocker arm and fixedly connected to the housing, wherein a predetermined vertical gap exists between the first sealing plate and the rocker arm; and A transverse sealing assembly includes a hinge and a second sealing plate. The two ends of the hinge in the length direction are connected to the housing. The second sealing plate is disposed at the movable end of the hinge and can freely rotate and fit against the outer side of the rocker arm as the rocker arm swings.

2. The sealing structure according to claim 1, characterized in that, The hinge includes a fixed pivot and a rotating sleeve fitted around the outer periphery of the fixed pivot. The rotating sleeve can rotate freely around the fixed pivot, and the second sealing plate is fixedly disposed on the outer wall of the rotating sleeve.

3. The sealing structure according to claim 2, characterized in that, The rotating sleeve is composed of several sleeve segments, each sleeve segment being fitted onto the outer circumference of the fixed rotating shaft, and each sleeve segment rotating freely around the fixed rotating shaft independently of each other.

4. The sealing structure according to claim 1, characterized in that, The upper end of the first sealing plate is connected to the housing wall at the opening of the housing, and the lower end extends obliquely away from the housing.

5. The sealing structure according to claim 2 or 3, characterized in that, The fixed rotating shaft is a steel bar with a nominal diameter of 25mm, and the rotating sleeve is a steel pipe with a nominal diameter of 32mm.

6. The sealing structure according to claim 5, characterized in that, The wall thickness of the rotating sleeve is 10 mm.

7. The sealing structure according to claim 1, characterized in that, The first sealing plate is a wear-resistant steel plate, and the Brinell hardness of the wear-resistant steel plate is not less than 500.

8. The sealing structure according to claim 7, characterized in that, The wear-resistant steel plate has a thickness of 14 mm.

9. The sealing structure according to claim 1, characterized in that, The preset vertical gap is 3-5mm.

10. A coal mill, characterized in that, It includes the housing, the rocker arm, and the sealing structure of the coal mill housing as described in any one of claims 1 to 9.

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