Butterfly valve for purifying flue
By using bearings to connect the neck flange in the butterfly valve and combining the design of the sealing unit, the problem of rust death caused by smoke contamination between the shaft and the shaft sleeve is solved, and smooth rotation and stability are achieved.
Patent Information
- Application Number
- CN202421068311.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-16
- Publication Date
- 2025-01-03
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
During use, the gap between the rotating shaft and the shaft sleeve is easily contaminated by tar and dust in the flue gas, resulting in rust and difficulty in opening and closing normally.
The design of connecting the bearing and the neck flange with the neck flange is adopted to reduce the friction of the shaft through the bearing, and a sealing unit is installed between the neck flange with the sleeve to prevent smoke leakage and prevent tar and dust from entering.
It realizes smooth rotation of the shaft, reduces friction, avoids rust, and ensures the stability and sealing effect of the butterfly valve.
Smart Images
Figure CN222296987U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of valve technology, and in particular to a butterfly valve for purifying a flue. Background Art
[0002] During the production process of the anode baking furnace in the carbon plant, harmful substances such as fluoride, asphalt smoke, dust, SO2 and benzopyrene will be emitted. These gases need to be comprehensively treated by a series of flue gas treatment processes to meet the national industrial gas emission standards before they can be discharged. Generally, the baking flue gas purification system will be equipped with a purification flue, a cooling tower, a bag filter, a main exhaust fan and a bypass fan. Among them, a butterfly valve is usually installed on the purification flue to control the flow of flue gas in the flue. The commonly used butterfly valve structure is roughly as follows: the valve plate is connected to the rotating shaft through a locating pin and placed in the valve body cavity, the rotating shaft is placed in the shaft sleeve and positioned in the valve body, and a sealing ring and a sealing pressure ring are provided in the valve body cavity that cooperates with the valve plate. The packing is arranged in the valve body shaft hole, and a packing gland is provided on it. The upper part of the valve body is provided with an upper flange and a connecting support, and the lower part is provided with an end cover. The cylindrical sleeve that protects the shaft is called a sleeve. When in use, the shaft of the butterfly valve will directly contact the inner wall of the sleeve. Therefore, the gap between the shaft and the sleeve of the butterfly valve is relatively small, and the sleeve is located on the inner side of the packing in the valve body. During use, although the packing can prevent smoke from leaking from the joint between the shaft and the valve body, the smoke will still penetrate into the gap between the sleeve and the shaft of the butterfly valve. The asphalt smoke in the smoke entering between the sleeve and the shaft contains tar. These tars and other particles such as dust gather in the gap between the sleeve and the shaft and easily rust the sleeve and the shaft, making it difficult to open and close normally. Utility Model Content
[0003] The present application provides a butterfly valve for purifying flue gas, which can prevent tar and dust in flue gas from penetrating into the gap between the rotating shaft and the shaft sleeve during the use of the butterfly valve, making it difficult for the rotating shaft to open and close normally during use.
[0004] The above-mentioned purpose of the present application is achieved through the following technical solutions:
[0005] A butterfly valve for flue purification, comprising a valve body, a valve plate and a rotating shaft, wherein a sleeve is provided in the middle of the valve plate, the rotating shaft passes through the sleeve and the two are fixedly connected by a pin, and an axial hole is provided on both the upper and lower sides of the valve body, and the two axial holes are symmetrical about the center point of the valve body;
[0006] Both ends of the sleeve and the rotating shaft are respectively located in the two shaft holes, and a fixing component is provided in each of the two shaft holes; the fixing component can enable the sleeve and the rotating shaft at corresponding positions to rotate freely in the shaft holes;
[0007] The fixing assembly includes a neck flange, which is coaxially sleeved on the outside of the sleeve and the rotating shaft, and the neck of the neck flange is inserted into the shaft hole at a corresponding position and fixedly connected to the shaft hole; a bearing is provided in the gap between the neck flange and the rotating shaft, the outer ring of the bearing is fixedly connected to the neck flange, and the inner ring of the bearing is fixedly connected to the rotating shaft; a sealing unit for preventing smoke leakage is provided in the gap between the neck flange and the sleeve.
[0008] Furthermore, a horizontal plate is fixedly connected to the neck of the neck flange near the port on one side of the valve plate, the horizontal plate is sleeved on the outside of the sleeve and the two are rotatably connected, and the sealing unit is installed on the horizontal plate.
[0009] Furthermore, the diameters of the two ends of the shaft located outside the sleeve are smaller than the diameter of the shaft located inside the sleeve; the inner diameter of the bearing inner ring is similar to the diameter of the shaft end located outside the sleeve, and the outer diameter of the bearing outer ring is similar to the outer diameter of the sleeve.
[0010] Furthermore, a fixing ear plate is fixedly connected to an opposite side of the outer ring of the bearing away from one end of the valve plate, and the fixing ear plate and the neck flange at the corresponding position can be fixedly connected by bolts.
[0011] Furthermore, the sealing unit includes a filler, which fills the space enclosed by the horizontally placed plate, the neck flange and the sleeve; a pressure cover is provided on the side of the filler away from the horizontally placed plate, the pressure cover is detachably connected to the inner wall of the neck flange, and the pressure cover is tightly pressed on the filler at one end close to the horizontally placed plate.
[0012] Furthermore, the gland is threadedly connected to the inner wall of the neck flange, and after the gland compacts the filler, the end of the gland away from the horizontally placed plate is not higher than the flange end face of the neck flange.
[0013] Furthermore, a protrusion is provided on the inner side of the inner ring of the bearing, and a corresponding groove is provided on the outer side of the rotating shaft. When the inner ring of the bearing is sleeved on the rotating shaft, the protrusion is inserted into the groove, and the rotating shaft can rotate with the inner ring of the bearing through the limiting effect of the groove on the protrusion.
[0014] In summary, the present application includes at least one of the following beneficial technical effects:
[0015] In the present application, the shaft holes on the upper and lower sides of the valve body are connected to the two ends of the middle shaft of the valve plate through a bearing respectively, so that when the valve plate is opened and closed in the valve body, the two ends of the shaft can rotate smoothly in the valve body through the bearing. Compared with the shaft being movably connected to the valve body through the sleeve, the bearing reduces the friction force on the shaft when rotating, so that the valve plate rotates more smoothly in the valve body and better guarantees the rotation accuracy. In addition, the present application is provided with a sealing unit in the gap between the neck flange and the sleeve for installing the bearing, and the sealing unit can effectively prevent the smoke from leaking out from the joint between the sleeve and the neck flange during the use of the butterfly valve. Since the bearing at the connection between the shaft and the valve body on the valve plate of the present application will not contact the internal smoke, it will not easily be rusted by tar and dust in the smoke during use, so that the stability of the butterfly valve can be guaranteed during use. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 It is a schematic diagram of the overall structure of this application;
[0018] Figure 2 It is a cross-sectional view of the upper local structure of the butterfly valve of the present application;
[0019] Figure 3 yes Figure 2 A schematic diagram of the enlarged structure at A in the middle;
[0020] Figure 4 It is a schematic diagram of the partial structure of the butterfly valve of the present application in a top view.
[0021] Figure numerals: 1. valve body; 2. valve plate; 3. rotating shaft; 4. sleeve; 5. shaft hole; 6. fixing assembly; 61. neck flange; 62. bearing; 63. sealing unit; 631. packing; 632. gland; 7. horizontal placement plate; 8. fixing ear plate; 9. protrusion; 10. groove. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.
[0023] like Figure 1-Figure 3 As shown, a butterfly valve for flue purification disclosed in the present application comprises a valve body 1, a valve plate 2 and a rotating shaft 3, a sleeve 4 is provided in the middle of the valve plate 2, the rotating shaft 3 passes through the sleeve 4 and the two are fixedly connected by a pin, an axial hole 5 is provided on both the upper and lower sides of the valve body 1, and the two axial holes 5 are symmetrical about the center point of the valve body 1;
[0024] Both ends of the sleeve 4 and the rotating shaft 3 are respectively located in two shaft holes 5, and a fixing component 6 is provided in each of the two shaft holes 5; the fixing component 6 can enable the sleeve 4 and the rotating shaft 3 at the corresponding position to rotate freely in the shaft hole 5;
[0025] The fixing assembly 6 includes a neck flange 61, which is coaxially sleeved on the outside of the sleeve 4 and the rotating shaft 3, and the neck of the neck flange 61 is inserted into the shaft hole 5 at the corresponding position and fixedly connected to the shaft hole 5; a bearing 62 is provided in the gap between the neck flange 61 and the rotating shaft 3, the outer ring of the bearing 62 is fixedly connected to the neck flange 61, and the inner ring of the bearing 62 is fixedly connected to the rotating shaft 3; a sealing unit 63 for preventing smoke leakage is provided in the gap between the neck flange 61 and the sleeve 4.
[0026] In the above embodiments, since the connection principle of the sleeve 4 on the valve plate 2 and the upper and lower ends of the rotating shaft 3 with the valve body 1 is the same, only Figure 1 The connection method and principle between the upper end of the middle sleeve 4 and the upper end of the rotating shaft 3 and the valve body 1 are explained. Compared with ordinary flanges, the neck flange 61 of the present application has an additional neck tube, which is convenient to be inserted into the shaft hole 5 of the valve body 1, thereby fixing the neck flange 61 as a whole to the valve body 1. After the rotating shaft 3 is fixedly connected with the sleeve 4 on the valve plate 2, they can be regarded as an integral structure. The length of the rotating shaft 3 is greater than the sleeve 4, and the two ends of the rotating shaft 3 will extend out of the two ends of the sleeve 4 by a certain distance, so that it is convenient to connect the driving parts such as the hand wheel to the rotating shaft 3, so that the opening and closing effect of the butterfly valve is realized by rotating the valve plate 2 in the valve body 1 with the rotating shaft 3. The inner diameter of the neck flange 61 is larger than the sleeve 4 and the rotating shaft 3, so there is a certain gap between the neck flange 61 and the sleeve 4 and the rotating shaft 3. The bearing 62 is installed in the gap between the part of the rotating shaft 3 extending out of the sleeve 4 and the neck flange 61, and the outer ring of the bearing 62 is connected to the neck flange 61, and the inner ring of the bearing 62 is connected to the rotating shaft 3. During the rotation of the rotating shaft 3, since there is a ball between the inner ring and the outer ring of the bearing 62, the sliding friction of the rotating shaft 3 can be converted into rolling friction with less resistance, so that the butterfly valve will be opened and closed more smoothly by means of a driving part such as a hand wheel, and the corresponding opening or closing angle can be controlled more accurately.
[0027] Since there may be a joint between the sleeve 4 and the neck flange 61 to ensure the rotation of the sleeve 4, the joint may cause the risk of smoke leakage in the clean smoke pipe during use. Therefore, the present application sets a sealing unit 63 in the gap between the upper end of the sleeve 4 and the neck flange 61 at the corresponding position, so as to seal the joint between the sleeve 4 and the neck flange 61 to prevent smoke leakage and pollute the environment. At the same time, it can also prevent the smoke from entering the bearing 62 during the process of spreading upward along the sleeve 4, affecting its normal use.
[0028] The butterfly valve structure currently commonly used in pipelines can refer to the butterfly valve structure in the Chinese patent with application number 200520026795.X. The rotating shaft 3 on the valve plate 2 of this type of butterfly valve is connected to the valve body 1 through a shaft sleeve, and the shaft sleeve is located in the valve body 1, and the filler 631 is located above the valve body 1. When there is smoke in the valve body 1, the smoke can easily get into the gap between the shaft sleeve and the rotating shaft 3. With the uneven deformation of the rotating shaft 3 and the shaft sleeve due to thermal expansion and contraction during use, it is easy to cause the rotating shaft 3 and the shaft sleeve to get stuck. When it is necessary to control the smoke flow in the pipeline, it is difficult to rotate the valve plate 2 in the valve body 1. Compared with the butterfly valve in the prior art in which the sleeve for connecting the valve body 1 and the rotating shaft 3 is arranged inside the valve body 1, the present application adopts a bearing 62 with smaller resistance to flexibly connect the rotating shaft 3 and the valve body 1, which can not only make the working process of the butterfly valve more stable and convenient and labor-saving to use, but also the bearing 62 of the present application will not come into contact with the flue gas in the valve body 1, so the tar and dust in the flue gas will hardly rust the bearing 62 and the rotating shaft 3, making it impossible to open and close normally.
[0029] Furthermore, if Figure 2 and Figure 3 As shown, a horizontal plate 7 is fixedly connected to the port of the neck of the neck flange 61 close to the valve plate 2. The horizontal plate 7 is sleeved on the outside of the sleeve 4 and the two are rotatably connected. The sealing unit 63 is installed on the horizontal plate 7.
[0030] In the above embodiments, the inner side of the horizontal plate 7 of the present application is rotatably connected to the sleeve 4 , and the horizontal plate 7 , the inner wall of the neck of the neck flange 61 and the outer wall of the sleeve 4 can form a cavity for installing the sealing unit 63 . In addition, although there is a gap between the horizontal plate 7 of the present application and the sleeve 4, smoke may enter the gap, but the main function of the horizontal plate 7 of the present application is to prevent the filler 631 between the neck flange 61 and the sleeve 4 from entering the valve body 1. Therefore, the thickness of the horizontal plate 7 can be set very thin, so that the contact area between the horizontal plate 7 and the sleeve 4 is actually very small, and the filler 631 is above the horizontal plate 7. Even if the smoke in the valve body 1 enters the joint with the small height of the horizontal plate 7 and the sleeve 4, it will not continue to spread upward, and the contact area between the sleeve 4 and the horizontal plate 7 is very small, and the amount of tar and dust that can be accommodated is very limited, especially compared with the contact area between the sleeve and the rotating shaft 3 in the prior art. Therefore, even if some smoke enters this area, it will not produce too much resistance to the rotation of the rotating shaft 3 and the sleeve 4, thereby affecting the normal operation of the butterfly valve.
[0031] Furthermore, if Figure 2 and Figure 3 As shown, the diameters of the two ends of the shaft 3 located outside the sleeve 4 are smaller than the diameter of the parts located inside the sleeve 4; the inner diameter of the inner ring of the bearing 62 is close to the diameter of the end of the shaft 3 located outside the sleeve 4, and the outer diameter of the outer ring of the bearing 62 is close to the outer diameter of the sleeve 4.
[0032] In the above embodiment, the rotating shaft 3 and the bearing 62 of the present application are arranged in the above manner, and when the bearing 62 is installed on the rotating shaft 3, a step can be provided at the place where the diameter of the end of the rotating shaft 3 changes, and the step can limit the inner ring of the bearing 62, so as to facilitate the worker to quickly position the bearing 62 on the rotating shaft 3. The outer diameter of the outer ring of the bearing 62 is close to the outer diameter of the sleeve 4, so that after the bearing 62 is installed on the rotating shaft 3, the outer wall of the outer ring of the bearing 62 and the outer wall of the sleeve 4 can form an annular cavity with uniform shape from top to bottom with the inner wall of the neck flange 61, thereby providing a larger installation space for the sealing unit 63.
[0033] Furthermore, if Figure 2-Figure 4 As shown, a fixing ear plate 8 is fixedly connected to the opposite side of the outer ring of the bearing 62 away from the end of the valve plate 2, and the fixing ear plate 8 can be fixedly connected to the neck flange 61 at the corresponding position by bolts.
[0034] In the above embodiment, the height of the outer ring of the bearing 62 is greater than the height of its inner ring, and the two fixed ear plates 8 on the outer ring of the bearing 62 are respectively arranged on opposite sides of the part thereof higher than the inner ring. When the inner ring of the bearing 62 contacts the step at the diameter change position on the rotating shaft 3, the two fixed ear plates 8 just fit with the flange end face of the neck flange 61. Threaded holes are arranged on the two fixed ear plates 8, and the flange end face of the neck flange 61 is provided with the same specifications as the threaded holes on the two fixed ear plates 8. In this way, after the bearing 62 and the rotating shaft 3 are assembled, the threaded holes of the two fixed ear plates 8 are aligned with the threaded holes on the flange end face of the neck flange 61, and the outer ring of the bearing 62 and the neck flange 61 can be fixedly connected together by bolts.
[0035] Furthermore, if Figure 2 and Figure 3 As shown, the sealing unit 63 includes a packing 631, which fills the space enclosed by the horizontally placed plate 7, the neck flange 61 and the sleeve 4; a pressure cover 632 is provided on the side of the packing 631 away from the horizontally placed plate 7, and the pressure cover 632 is detachably connected to the inner wall of the neck flange 61, and the pressure cover 632 is tightly pressed on the packing 631 at one end close to the horizontally placed plate 7.
[0036] In the above embodiments, the rotating shaft 3 can drive the valve plate 2 to open and close in the valve body 1 , so the rotating shaft 3 is a movable part in the valve, and therefore there is a gap between the rotating shaft 3 and the valve body 1 . The shaft hole 5 of the present application is used to pass through the rotating shaft 3 and the sleeve 4, and the inner side of the shaft hole 5 is fixedly connected with the neck flange 61, and the two are an integral structure. Therefore, the main gap between the rotating shaft 3 and the valve body 1 of the present application exists in the contact area with the horizontal plate 7 and the sleeve 4. In order to prevent the smoke in the flue from leaking out from the gap, the present application fills the packing 631 in the cavity surrounded by the horizontal plate 7, the sleeve 4 and the neck flange 61, and generates an axial extrusion force on the packing 631 by inserting a pressure cover 632 above the packing 631, so that the packing 631 radially expands in the space surrounded by the horizontal plate 7, the sleeve 4 and the neck flange 61, and is in close contact with the surface of the sleeve 4 and generates a contact force, so that the smoke is blocked when flowing outward from the joint of the horizontal plate 7 and the sleeve 4, thereby sealing the butterfly valve and the smoke inside the flue. The filler 631 is an existing technology. Commonly used fillers 631 include PTFE (polytetrafluoroethylene filler 631), flexible graphite combined with stainless steel wire mesh, asbestos filler 631, flax filler 631, etc. In the actual production process, technicians can select corresponding fillers 631 according to the specific medium transported by the flue.
[0037] Furthermore, if Figure 3 As shown, the pressure cover 632 is threadedly connected to the inner wall of the neck flange 61 , and after the pressure cover 632 compacts the filler 631 , the end of the pressure cover 632 away from the horizontally placed plate 7 is not higher than the flange end surface of the neck flange 61 .
[0038] In the above embodiments, the gland 632 of the present application is a hollow cylinder, whose inner diameter is close to the outer diameter of the outer ring of the bearing 62, and whose outer diameter is close to the inner diameter of the neck flange 61, and the outer wall of the gland 632 is threadedly connected to the inner wall of the neck flange 61. After the packing 631 is filled on the horizontal plate 7, the gland 632 can be screwed on the inner side of the neck flange 61 to compress the packing 631 on the horizontal plate 7, thereby ensuring the sealing effect of the packing 631. The height of the gland 632 of the present application satisfies that after it compresses the packing 631, the top of the gland 632 will not be higher than the end face height of the flange end of the neck flange 61, so that the installed gland 632 will not affect the installation of the fixed ear plate 8 of the bearing 62.
[0039] Furthermore, if Figure 2-Figure 4 As shown, a protrusion 9 is provided on the inner side of the inner ring of the bearing 62, and a corresponding groove 10 is provided on the outer side of the rotating shaft 3. When the inner ring of the bearing 62 is sleeved on the rotating shaft 3, the protrusion 9 is inserted into the groove 10, and the rotating shaft 3 can rotate with the inner ring of the bearing 62 through the limiting effect of the groove 10 on the protrusion 9.
[0040] In the above embodiments, when the bearing 62 of the present application is installed on the rotating shaft 3, the protrusion 9 on the inner ring of the bearing 62 can be aligned with the groove 10 on the rotating shaft 3, and then the bearing 62 can be lowered along the axial direction of the rotating shaft 3. At this time, the threaded holes on the two fixed ear plates 8 are also just aligned with the corresponding threaded holes on the neck flange 61, until the inner ring of the rotating shaft 3 contacts the step at the diameter change point on the rotating shaft 3, and then the fixed ear plate 8 and the neck flange 61 are connected by bolts. Since the protrusion 9 on the inner ring of the bearing 62 is inserted into the groove 10 on the shaft 3, when the shaft 3 rotates, the inner ring of the bearing 62 can be rotated together through the limiting effect of the groove 10 on the protrusion 9. Compared with the traditional way of connecting the bearing 62 and the shaft 3 through interference fit, the bearing 62 and the shaft 3 of the present application are more convenient to disassemble later. Moreover, when the bearing 62 is sleeved on the shaft 3, the threaded holes on the two fixing ear plates 8 are automatically aligned with the threaded holes on the neck flange 61, thereby improving the subsequent installation efficiency.
[0041] The implementation principle of this embodiment is as follows: after the butterfly valve of this application is installed on the purified flue, during normal use, the worker can rotate one end of the rotating shaft 3 through a hand wheel or other driving parts, thereby rotating the valve plate 2 in the valve body 1 through the sleeve 4 to adjust the flue gas flow rate. Since the rotating shaft 3 of this application is connected to the valve body 1 through a bearing 62, the rotating shaft 3 is more labor-saving and smoother than the method of connecting the rotating shaft 3 through a sleeve in the prior art. Moreover, a sealing unit 63 is provided on the side of the bearing 62 of this application close to the valve plate 2. The sealing unit 63 can seal the butterfly valve to prevent the internal flue gas from leaking out. Therefore, the bearing 62 of this application will not come into contact with the flue gas during use like the sleeve in the prior art. Therefore, the rotating shaft 3 of this application will not easily rust due to tar and dust in the flue gas during use, which can ensure its stability during use.
[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A butterfly valve for purifying a flue, comprising a valve body (1), a valve plate (2) and a rotating shaft (3), wherein a sleeve (4) is provided in the middle of the valve plate (2), the rotating shaft (3) passes through the sleeve (4) and the two are fixedly connected by a pin, characterized in that: An axial hole (5) is provided on both the upper and lower sides of the valve body (1), and the axial holes (5) are symmetrical about the center point of the valve body (1); Both ends of the sleeve (4) and the rotating shaft (3) are respectively located in the two shaft holes (5), and a fixing component (6) is provided in each of the two shaft holes (5); the fixing component (6) enables the sleeve (4) and the rotating shaft (3) at corresponding positions to rotate freely in the shaft holes (5); The fixing assembly (6) comprises a neck flange (61), wherein the neck flange (61) is coaxially sleeved on the outer sides of the sleeve (4) and the rotating shaft (3), and the neck of the neck flange (61) is inserted into the shaft hole (5) at a corresponding position and fixedly connected to the shaft hole (5); a bearing (62) is provided in the gap between the neck flange (61) and the rotating shaft (3), the outer ring of the bearing (62) is fixedly connected to the neck flange (61), and the inner ring of the bearing (62) is fixedly connected to the rotating shaft (3); a sealing unit (63) for preventing smoke leakage is provided in the gap between the neck flange (61) and the sleeve (4).
2. The butterfly valve for flue purification according to claim 1, characterized in that: A horizontal placement plate (7) is fixedly connected to the neck of the neck flange (61) at a port close to one side of the valve plate (2); the horizontal placement plate (7) is sleeved on the outside of the sleeve (4) and the two are rotatably connected; and the sealing unit (63) is mounted on the horizontal placement plate (7).
3. The butterfly valve for flue purification according to claim 1 or 2, characterized in that: The diameters of the two ends of the rotating shaft (3) located outside the sleeve (4) are both smaller than the diameter of the parts located inside the sleeve (4); the inner diameter of the inner ring of the bearing (62) is close to the diameter of the end of the rotating shaft (3) located outside the sleeve (4), and the outer diameter of the outer ring of the bearing (62) is close to the outer diameter of the sleeve (4).
4. The butterfly valve for flue purification according to claim 3 is characterized in that: A fixing ear plate (8) is fixedly connected to the opposite side of the outer ring of the bearing (62) away from one end of the valve plate (2), and the fixing ear plate (8) can be fixedly connected to the neck flange (61) at the corresponding position by bolts.
5. The butterfly valve for flue purification according to claim 2, characterized in that: The sealing unit (63) includes a filler (631), and the filler (631) fills the space enclosed by the horizontally placed plate (7), the neck flange (61) and the sleeve (4); a pressure cover (632) is provided on the side of the filler (631) away from the horizontally placed plate (7), and the pressure cover (632) is detachably connected to the inner wall of the neck flange (61), and the pressure cover (632) is tightly pressed on the filler (631) at one end close to the horizontally placed plate (7).
6. The butterfly valve for flue purification according to claim 5, characterized in that: The pressure cover (632) is threadedly connected to the inner wall of the neck flange (61), and after the pressure cover (632) compacts the filler (631), the end of the pressure cover (632) away from the horizontally placed plate (7) is not higher than the flange end surface of the neck flange (61).
7. The butterfly valve for flue purification according to claim 1 or 2, characterized in that: A protrusion (9) is provided on the inner side of the inner ring of the bearing (62), and a corresponding groove (10) is provided on the outer side of the rotating shaft (3). When the inner ring of the bearing (62) is sleeved on the rotating shaft (3), the protrusion (9) is inserted into the groove (10), and the rotating shaft (3) can rotate together with the inner ring of the bearing (62) through the limiting effect of the groove (10) on the protrusion (9).