Sealing device for drying machine and drying machine

Abstract

The utility model relates to the technical field of drying machines, and discloses a sealing device for a drying machine and the drying machine. The sealing device for the drying machine is used for sealing a gap between a shell of the drying machine and a rotating shaft penetrating through the shell, the sealing device is arranged outside the shell and comprises a first sealing structure, the first sealing structure is installed on the outer side wall of the shell and comprises a movable sealing ring and a static sealing ring, the movable sealing ring fixedly sleeves the rotating shaft, and the static sealing ring fixedly sleeves the rotating shaft. The inner diameter of the movable sealing ring is smaller than the aperture of a first through hole, allowing the rotating shaft to penetrate through, in the shell, the outer diameter of the movable sealing ring is larger than the aperture of the first through hole, and the static sealing ring is fixed to the shell, arranged outside the movable sealing ring in a sleeving mode and matched with the movable sealing ring in a rotating mode. The first through hole of the shell, the contact face position of the bottom face of the movable sealing ring and the shell and the contact side wall of the movable sealing ring and the static sealing ring form effective step-shaped sealing fit, and the sealing effect of the sealing device is further improved.

Description

Technical Field

[0001] This utility model relates to the field of dryer technology, specifically to a sealing device for a dryer and a dryer. Background Technology

[0002] A dryer is a mechanical device that uses heat energy to reduce the moisture content of materials, used for drying operations. The dryer heats the material to vaporize and release the moisture (generally water or other volatile liquid components) to obtain a solid material with a specified moisture content.

[0003] A dryer generally includes a shell and a feeding mechanism. The shell has a partition plate with a feeding port on the partition plate. The feeding mechanism includes a rotating shaft passing through the shell, a drive mechanism, and a feeding gate. The rotating shaft passes through the side wall of the shell and is connected to the drive mechanism located on the outside of the dryer. The drive mechanism drives the rotating shaft to rotate, thereby causing the feeding gate located on the other side of the rotating shaft to open or close the feeding port on the partition plate.

[0004] However, in existing technologies, the shaft and the housing are generally sealed only by simple sealing methods such as traditional sealing rings. When the shaft rotates relative to the housing, the sealing ring is prone to wear or displacement, resulting in reduced sealing performance and failure to provide a good seal for the dryer, which can easily cause material leakage. Utility Model Content

[0005] The purpose of this invention is to overcome the technical problem of poor sealing performance between the rotating shaft and the shell in existing dryers, which easily leads to material leakage. This invention provides a sealing device and a dryer for use in dryers. The sealing device has the technical effect of improving the sealing performance between the rotating shaft and the shell and preventing material leakage inside the shell.

[0006] To achieve the above objectives, this utility model provides a sealing device for a dryer, used to seal the gap between the dryer's housing and a rotating shaft passing through the housing. The sealing device is disposed outside the housing and includes a first sealing structure. The first sealing structure is installed on the outer side wall of the housing and includes: a dynamic sealing ring, which is fixedly sleeved on the rotating shaft, with an inner diameter smaller than the diameter of a first through hole on the housing through which the rotating shaft passes, and an outer diameter larger than the diameter of the first through hole; and a static sealing ring, which is fixed to the housing and sleeved outside the dynamic sealing ring and rotatably engaged with it.

[0007] Preferably, the dynamic sealing ring and the static sealing ring are fitted together by a complementary structure.

[0008] Preferably, the inner wall of the static sealing ring is stepped, and the outer wall of the dynamic sealing ring is stepped to mate with the inner wall of the static sealing ring.

[0009] Preferably, the sealing device further includes: a sleeve disposed on the outer side wall of the housing and sleeved on the outside of the rotating shaft, the inner side wall of the sleeve being fixedly connected to the static sealing ring; and a second sealing structure disposed at the end of the sleeve away from the housing, and the second sealing structure being configured to be sleeved on the rotating shaft to seal the cavity formed between the sleeve, the first sealing structure and the rotating shaft.

[0010] Preferably, the second sealing structure includes: an end cap, which is detachably disposed at the end of the sleeve away from the housing and is sleeved on the outside of the rotating shaft; and a sealing ring, which is sealed between the end cap and the rotating shaft and is rotatably engaged with the rotating shaft.

[0011] Preferably, the inner diameter of the end cap is smaller than the outer diameter of the dynamic sealing ring.

[0012] Preferably, a sealing cavity is formed between the sleeve, the first sealing structure, the rotating shaft, and the second sealing structure, and the sealing cavity is configured to allow compressed air to be input.

[0013] Preferably, the sealing device further includes a base, which is detachably mounted on the outer side wall of the housing and has a second through hole for the rotating shaft to pass through. The first sealing structure is mounted on the base, and the diameter of the second through hole is smaller than the outer diameter of the dynamic sealing ring and larger than the inner diameter of the dynamic sealing ring.

[0014] Preferably, both the dynamic sealing ring and the static sealing ring are made of corrosion-resistant metal material.

[0015] In another aspect, this utility model also provides a dryer, including a housing, a rotating shaft, and a sealing device for the dryer as described in any of the above embodiments. The rotating shaft passes through the housing, and the sealing device is disposed outside the housing and is used to seal the gap between the housing and the rotating shaft.

[0016] Through the above technical solution, the first sealing structure set on the outer wall of the shell can effectively seal the gap between the shell and the rotating shaft, preventing material from leaking out of the dryer through the gap and ensuring the normal operation and long-term stability of the dryer. Placing the sealing device outside the shell avoids interference from the complex internal environment of the dryer, facilitating installation and maintenance. The inner diameter of the dynamic sealing ring of the first sealing structure is smaller than the diameter of the first through hole, while the outer diameter of the dynamic sealing ring is larger than the diameter of the first through hole. The dynamic sealing ring is fixedly sleeved on the rotating shaft, ensuring that the bottom surface of the dynamic sealing ring in contact with the shell covers and seals the gap, preventing material from leaking out of the dryer and ensuring the tightness of the sealing device. Sealing effect: The fixed static sealing ring to the shell prevents material leakage from the connection between the static sealing ring and the shell, and also prevents displacement of the static sealing ring, improving the stability and firmness of the positions of the dynamic and static sealing rings. At the same time, the first through hole of the shell, the contact surface between the bottom surface of the dynamic sealing ring and the shell, and the contact sidewalls of the dynamic and static sealing rings form an effective stepped sealing fit, further improving the sealing effect of the sealing device. The rotational fit between the static and dynamic sealing rings ensures that the rotating shaft can rotate stably while the sealing device seals the gaps. This sealing device can improve the sealing performance between the rotating shaft and the shell, preventing material leakage from inside the shell. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a sealing device for a dryer according to an embodiment of the present disclosure;

[0018] Figure 2 This is a schematic diagram of the structure of the sealing device and the rotating shaft for use in a dryer according to an embodiment of the present disclosure;

[0019] Figure 3 This is a cross-sectional view of one embodiment of a first sealing structure for a sealing device for a dryer according to an embodiment of the present disclosure;

[0020] Figure 4 This is a schematic diagram of a sealing device for a dryer installed in a dryer according to an embodiment of this disclosure; and

[0021] Figure 5 yes Figure 4 Enlarged cross-sectional view of section A.

[0022] Explanation of reference numerals in the attached figures

[0023] 1. First sealing structure; 11. Dynamic sealing ring; 12. Static sealing ring; 2. Sleeve; 21. Air inlet; 3. Second sealing structure; 31. End cap; 32. Sealing ring; 4. Sealing cavity; 5. Rotating shaft; 6. Base; 61. Second through hole; 7. Housing; 8. Divider plate; 9. Flat flange; 10. Discharge gate. Detailed Implementation

[0024] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0025] This utility model provides a sealing device for a dryer, used to seal the gap between the dryer's housing 7 and the rotating shaft 5 passing through the housing 7. See [link to relevant documentation]. Figure 1 and Figure 2 The sealing device is located outside the housing 7 and includes a first sealing structure 1. The first sealing structure 1 is installed on the outer side wall of the housing 7. The first sealing structure 1 includes a dynamic sealing ring 11 and a static sealing ring 12. The dynamic sealing ring 11 is fixedly sleeved on the rotating shaft 5. The inner diameter of the dynamic sealing ring 11 is smaller than the diameter of the first through hole on the housing 7 through which the rotating shaft 5 passes. The outer diameter of the dynamic sealing ring 11 is larger than the diameter of the first through hole. The static sealing ring 12 is fixed to the housing 7. The static sealing ring 12 is sleeved outside the dynamic sealing ring 11 and rotates with the dynamic sealing ring 11. The first sealing structure 1, located on the outer wall of the housing 7, effectively seals the gap between the housing 7 and the rotating shaft 5, preventing material leakage from the dryer and ensuring the normal operation and long-term stability of the dryer. Positioning the sealing device outside the housing 7 avoids interference from the complex internal environment of the dryer, facilitating installation and maintenance. The inner diameter of the dynamic sealing ring 11 of the first sealing structure 1 is smaller than the diameter of the first through hole, while the outer diameter of the dynamic sealing ring 11 is larger than the diameter of the first through hole. The dynamic sealing ring 11 is fixedly fitted onto the rotating shaft 5, ensuring that the bottom surface of the dynamic sealing ring 11 in contact with the housing 7 covers and seals the gap, preventing material leakage from the dryer and guaranteeing the sealing effect of the sealing device. The static sealing ring 12 is fixed... The placement of the housing 7 prevents material leakage from the connection between the static sealing ring 12 and the housing 7, and also prevents displacement of the static sealing ring 12, improving the stability and firmness of the positions of the dynamic sealing ring 11 and the static sealing ring 12. Simultaneously, the first through hole of the housing 7, the contact surface between the bottom surface of the dynamic sealing ring 11 and the housing 7, and the contact sidewalls of the dynamic sealing ring 11 and the static sealing ring 12 form an effective stepped sealing fit, further improving the sealing effect of the sealing device. The rotational fit between the static sealing ring 12 and the dynamic sealing ring 11 ensures that the rotating shaft 5 can rotate stably while the sealing device seals the gap. This sealing device improves the sealing performance between the rotating shaft 5 and the housing 7, preventing material leakage within the housing 7.

[0026] As one embodiment, the sealing device proposed in this disclosure is also applicable to other equipment that requires ensuring a sealed and dry internal environment.

[0027] As one embodiment, the dynamic sealing ring 11 is fixed to the rotating shaft 5 by an interference fit.

[0028] Preferably, in order to further improve the sealing effect between the dynamic sealing ring 11 and the static sealing ring 12 and prevent material leakage, the dynamic sealing ring 11 and the static sealing ring 12 are fitted with a complementary structure.

[0029] In the above, the complementary structure between the dynamic sealing ring 11 and the static sealing ring 12 can be implemented in various ways, as long as it increases the coverage area of ​​the dynamic sealing ring 11 and the static sealing ring 12 projected onto the bottom surface of the first sealing structure 1 along the axial direction. For example... Figure 3 In the illustrated embodiment, the inner wall of the static sealing ring 12 is stepped, and the outer wall of the dynamic sealing ring 11 is stepped to mate with the inner wall of the static sealing ring 12. This complementary stepped fit not only increases the contact area of ​​the sealing surfaces of the dynamic sealing ring 11 and the static sealing ring 12, but also increases the coverage area of ​​the dynamic sealing ring 11 and the static sealing ring 12 projected onto the bottom surface of the first sealing structure 1 along the axial direction, thus reducing the risk of leakage.

[0030] In another embodiment, the inner wall of the static sealing ring 12 is configured as an arc shape, and the outer wall of the dynamic sealing ring 11 is configured as an arc shape that matches the inner wall of the static sealing ring 12.

[0031] In another embodiment, the inner wall of the static sealing ring 12 is configured as a frustum shape, and the outer wall of the dynamic sealing ring 11 is configured as a frustum shape that mates with the inner wall of the static sealing ring 12.

[0032] Preferably, the dynamic sealing ring 11 and the static sealing ring 12 are detachably installed.

[0033] Preferably, see Figure 1 The sealing device also includes a sleeve 2 and a second sealing structure 3. The sleeve 2 is disposed on the outer side wall of the housing 7 and sleeved on the outside of the rotating shaft 5. The inner side wall of the sleeve 2 is fixedly connected to the static sealing ring 12. The second sealing structure 3 is disposed at the end of the sleeve 2 away from the housing 7 and is configured to be sleeved on the rotating shaft 5 to seal the cavity formed between the sleeve 2, the first sealing structure 1 and the rotating shaft 5. The cooperation between the second sealing structure 3 and the rotating shaft 5 effectively prevents material leakage from the gap between the sleeve 2 and the rotating shaft 5, improving the sealing effect. Furthermore, the second sealing structure 3 forms a sealed chamber between the rotating shaft 5, the sleeve 2, and the first sealing structure 1, further enhancing the sealing effect of the sealing device. The combination of the first sealing structure 1, the chamber, and the second sealing structure 3 creates multiple sealing barriers. Compared to the existing technology that only seals the gap between the housing 7 and the rotating shaft 5 with a sealing ring, this method provides multi-layered, step-by-step sealing of the gap between the housing 7 and the rotating shaft 5, improving the sealing effect of the sealing device. Moreover, the multi-layered sealing device extends the service life of the sealing device, reduces equipment downtime losses due to sealing device damage, and improves the continuity of dryer production.

[0034] As one embodiment, sleeve 2 is cylindrical.

[0035] In the above, there are multiple ways to fix the inner wall of the sleeve 2 to the static sealing ring 12. For example, the inner wall of the sleeve 2 and the outer wall of the static sealing ring 12 can be connected by an interference fit.

[0036] Preferably, the second sealing structure 3 includes an end cap 31 and a sealing ring 32. The end cap 31 is detachably disposed at the end of the sleeve 2 away from the housing 7, and the end cap 31 is sleeved on the outside of the rotating shaft 5. The sealing ring 32 is sealed between the end cap 31 and the rotating shaft 5, and rotates in cooperation with the rotating shaft 5. The detachable connection between the end cap 31 and the sleeve 2 facilitates the installation, maintenance, and replacement of the second sealing structure 3. The sealing ring 32 ensures stable rotation of the rotating shaft 5 while sealing the gap between the end cap 31 and the rotating shaft 5 to prevent material leakage. The cooperation between the end cap 31 and the sealing ring 32 forms an effective sealing barrier, ensuring that material will not leak from the end of the sleeve 2 away from the housing 7, further improving the sealing effect of the sealing device.

[0037] In the above, there are several ways in which the end cap 31 and the sleeve 2 can be detachably connected, for example... Figure 1 In the embodiment shown, the end cap 31 has several through holes along the circumference, and the bolt passes through the through holes and is threaded to the end of the sleeve 2 away from the housing 7.

[0038] As one embodiment, in order to improve the uniformity and stability of the circumferential force on the end cap 31, a number of perforations are evenly distributed along the circumference of the end cap 31.

[0039] As one embodiment, the outer diameter of the sealing ring 32 is larger than the inner diameter of the end cap 31, and the sealing ring 32 and the end cap 31 are fixedly connected by an interference fit.

[0040] As one embodiment, the sealing ring 32 is made of an elastic material.

[0041] As one embodiment, the sealing ring 32 is made of rubber material.

[0042] As one embodiment, the sealing ring 32 can be an O-ring or a lip seal.

[0043] Preferably, the inner diameter of the end cap 31 is smaller than the outer diameter of the dynamic sealing ring 11. The end cap 31 is positioned such that the contact surface between the end cap 31 and the sealing ring 32 is located at a different position in the radial direction of the rotating shaft 5 from the contact surface between the dynamic sealing ring 11 and the static sealing ring 12, thereby covering and sealing the contact surfaces of the dynamic sealing ring 11 and the static sealing ring 12 and further improving the sealing effect of the sealing device.

[0044] Preferably, a sealing cavity 4 is formed between the sleeve 2, the first sealing structure 1, the rotating shaft 5, and the second sealing structure 3. The sealing cavity 4 is configured to allow compressed air to be introduced. The pressure in the sealing cavity 4 filled with compressed air is greater than the external pressure. The first sealing structure 1 and the second sealing structure 3 located at both ends of the sleeve 2 will be subjected to pressure, thereby making the contact between the first sealing structure 1 and the housing 7 tighter, and the connection between the second sealing structure 3 and the sleeve 2 tighter, thus enhancing the sealing effect. At the same time, the compressed air can keep the sealing cavity 4 dry.

[0045] In the above, there are several ways to input compressed air into the sealed cavity 4, for example... Figure 1 In the embodiment shown, an air inlet 21 is provided on the outer wall of the sleeve 2. The compression device is connected to the air inlet 21 through an air inlet pipe, and the compressed air generated by the compression device can be input into the sealed cavity 4.

[0046] Preferably, the sealing device further includes a base 6, which is detachably mounted on the outer wall of the housing 7 and has a second through hole 61 for the rotating shaft 5 to pass through. The first sealing structure 1 is mounted on the base 6. The diameter of the second through hole 61 is smaller than the outer diameter of the dynamic sealing ring 11 and larger than the inner diameter of the dynamic sealing ring 11. The detachable arrangement of the base 6 and the housing 7 facilitates the installation, maintenance, and disassembly of the sealing device. The cooperation between the second through hole 61 of the base 6 and the dynamic sealing ring 11 forms a stepped contact surface between the base 6 and the first sealing structure 1, and the dynamic sealing ring 11 can cover and seal the second through hole 61 of the base 6, thereby improving the sealing effect of the sealing device.

[0047] As one embodiment, the sealing device with base 6 is particularly suitable for use in environments with high explosion-proof ratings, so as to facilitate quick disassembly and installation of the sealing device and ensure the safety of operators.

[0048] As one embodiment, the side of the base 6 that contacts the housing 7 is set to be arc-shaped to match the housing 7, thereby ensuring that the base 6 and the housing 7 fit tightly together and ensuring the stability of the base 6 installed on the housing 7.

[0049] As one embodiment, the diameter of the second through hole 61 of the base 6 is equal to the diameter of the first through hole of the housing 7.

[0050] As one embodiment, the diameter of the second through hole 61 of the base 6 is smaller than the diameter of the first through hole of the housing 7, so that the base 6 can cover and seal the gap between the housing 7 and the rotating shaft 5, and a multi-level stepped seal is formed by the housing 7, the base 6 and the first sealing structure 1 in the direction away from the housing, thereby improving the sealing effect.

[0051] In one embodiment, the diameter of the second through hole 61 of the base 6 is larger than the diameter of the first through hole of the housing 7. This facilitates the passage of the rotating shaft 5 through the base 6, and the first sealing structure 1 can effectively seal the gap between the rotating shaft 5 and the base 6.

[0052] In the above, there are several ways in which the base 6 and the housing 7 can be detachably connected. For example, the base 6 and the housing 7 can be detachably connected through a threaded structure.

[0053] As one embodiment, the base 6 includes a base plate and a side plate connected at an angle, the base plate being detachably connected to the housing 7; the side plate is used to mount the drive device for the drive shaft 5.

[0054] As one embodiment, the sleeve 2 is fixedly mounted on the base 6.

[0055] In the above, there are multiple ways to connect the sleeve 2 and the base 6. For example, the sleeve 2 and the base 6 can be fixedly connected by welding.

[0056] Preferably, both the dynamic sealing ring 11 and the static sealing ring 12 are made of corrosion-resistant metal material. By making the first sealing structure 1 of corrosion-resistant metal material, corrosion of the first sealing structure 1 by material leaking from the gap between the housing 7 and the rotating shaft 5 is prevented, ensuring the service life of the first sealing structure 1, thereby improving the sealing effect and stability of the sealing device.

[0057] The corrosion-resistant metal materials mentioned above can be of various types. For example, both the dynamic sealing ring 11 and the static sealing ring 12 are made of copper.

[0058] This utility model also provides a dryer, see [link to relevant documentation] Figure 4 and Figure 5 The dryer includes a housing 7, a rotating shaft 5, and a sealing device for the dryer according to any of the above-mentioned embodiments. The rotating shaft 5 passes through the housing 7, and the sealing device is located outside the housing 7 and is used to seal the gap between the housing 7 and the rotating shaft 5. The sealing device can effectively seal the dryer, prevent leakage of materials inside the dryer, and ensure the airtightness and safety of the dryer.

[0059] As one example, see Figure 5 The dryer also includes several partition plates 8 and a feeding mechanism. The partition plates 8 are located inside the housing 7 and have discharge ports. The feeding mechanism includes a drive device, a rotating shaft 5 and a feeding gate 10. The drive device is used to drive the rotating shaft 5 to open or close the feeding gate 10 located on the other side of the rotating shaft 5. The sealing device is located outside the housing 7 and is used to seal the gap between the housing 7 and the rotating shaft 5.

[0060] As one example, see Figure 5A flat flange 9 protrudes from the outer side wall of the dryer housing 7, through which the rotating shaft 5 passes. A sealing device is detachably mounted on the flat surface of the flat flange 9.

[0061] As one embodiment, the discharge gate 10 is an arc-shaped plate. The arc-shaped plate facilitates the movement of the discharge gate 10 away from or closing the discharge port when the drive device drives the rotating shaft 5 to rotate.

[0062] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solution of the present invention, including combinations of specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe the various possible combinations. However, these simple modifications and combinations should also be considered as part of the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A sealing device for a dryer, for sealing the gap between the dryer housing (7) and a rotating shaft (5) passing through the housing (7), characterized in that, The sealing device is disposed outside the housing (7) and includes a first sealing structure (1). The first sealing structure (1) is installed on the outer side wall of the housing (7). The first sealing structure (1) includes: A dynamic sealing ring (11) is fixedly sleeved on the rotating shaft (5). The inner diameter of the dynamic sealing ring (11) is smaller than the diameter of the first through hole on the housing (7) through which the rotating shaft (5) passes, and the outer diameter of the dynamic sealing ring (11) is larger than the diameter of the first through hole. A static sealing ring (12) is fixed to the housing (7). The static sealing ring (12) is sleeved outside the dynamic sealing ring (11) and rotates with the dynamic sealing ring (11).

2. The sealing device for a dryer according to claim 1, characterized in that, The dynamic sealing ring (11) and the static sealing ring (12) are fitted together by a complementary structure.

3. The sealing device for a dryer according to claim 2, characterized in that, The inner wall of the static sealing ring (12) is stepped, and the outer wall of the dynamic sealing ring (11) is stepped to cooperate with the inner wall of the static sealing ring (12).

4. The sealing device for a dryer according to claim 1, characterized in that, The sealing device further includes: A sleeve (2), the sleeve (2) being disposed on the outer side wall of the housing (7) and sleeved around the rotating shaft (5), the inner side wall of the sleeve (2) being fixedly connected to the static sealing ring (12); and The second sealing structure (3) is disposed at the end of the sleeve (2) away from the housing (7) and is configured to be sleeved on the rotating shaft (5) to seal the cavity formed between the sleeve (2), the first sealing structure (1) and the rotating shaft (5).

5. The sealing device for a dryer according to claim 4, characterized in that, The second sealing structure (3) includes: An end cap (31), said end cap (31) being detachably disposed at one end of the sleeve (2) away from the housing (7), and said end cap (31) being fitted over the rotating shaft (5); and A sealing ring (32) is provided between the end cap (31) and the rotating shaft (5) and is rotatably engaged with the rotating shaft (5).

6. The sealing device for a dryer according to claim 5, characterized in that, The inner diameter of the end cap (31) is smaller than the outer diameter of the dynamic sealing ring (11).

7. The sealing device for a dryer according to claim 4, characterized in that, A sealing cavity (4) is formed between the sleeve (2), the first sealing structure (1), the rotating shaft (5), and the second sealing structure (3), and the sealing cavity (4) is configured to receive compressed air.

8. The sealing device for a dryer according to any one of claims 1-7, characterized in that, The sealing device further includes a base (6), which is detachably mounted on the outer side wall of the housing (7) and has a second through hole (61) through which the rotating shaft (5) passes. The first sealing structure (1) is mounted on the base (6). The diameter of the second through hole (61) is smaller than the outer diameter of the dynamic sealing ring (11) and larger than the inner diameter of the dynamic sealing ring (11).

9. The sealing device for a dryer according to any one of claims 1-7, characterized in that, Both the dynamic sealing ring (11) and the static sealing ring (12) are made of corrosion-resistant metal materials.

10. A dryer, characterized in that, The device includes a housing (7), a rotating shaft (5), and a sealing device for a dryer according to any one of claims 1-9, wherein the rotating shaft (5) passes through the housing (7), and the sealing device is disposed outside the housing (7) and is used to seal the gap between the housing (7) and the rotating shaft (5).

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