Horizontal helical ribbon mixer and magnetofluid sealing device for sealing moving shaft of horizontal helical ribbon mixer

Abstract

The invention discloses a horizontal helical ribbon mixer and a magnetofluid sealing device for sealing a moving shaft thereof, the magnetofluid sealing device is mounted on a main shaft in the horizontal helical ribbon mixer, and the magnetofluid sealing device comprises a shaft sleeve, a sealing ring, a sealing ring and a sealing ring, the sealing shell and the sealing seat are sequentially arranged on the circumferential direction of the shaft sleeve in a sleeving mode, and the sealing seat is located at the end of the shaft sleeve; two air holes are formed in the sealing shell and provided with a ferrule type connector and a plug respectively, the ferrule type connector is used for communicating the first air hole with an external air source, and the plug is used for sealing the second air hole; the axial positioning assembly is axially connected with the sealing shell and the sealing seat; the magnetic fluid sealing assembly is arranged on the shaft sleeve in a sleeving mode and located in the sealing shell; the lip-shaped sealing ring is arranged in the sealing shell and located between the magnetofluid sealing assembly and the annular contact space, and an opening of the lip-shaped sealing ring faces the magnetofluid sealing assembly. According to the invention, the performance of the magnetofluid seal on the sealing of the movable shaft of the horizontal helical ribbon mixer is improved, and the service life is obviously prolonged.

Description

Technical Field

[0001] The invention relates to a dynamic shaft sealing device, in particular to a horizontal ribbon mixer and a magnetic fluid sealing device for dynamic shaft sealing thereof. Background Art

[0002] Mixing is an indispensable production process in modern industry. With the continuous development of China's industry, the development of mixing systems and mixing equipment will become more and more powerful. Mixing covers the entire industrial field, such as chemicals, food, building materials, pharmaceuticals, and fertilizers.

[0003] Ribbon mixers are generally used for mixing viscous or cohesive powders and particles, as well as for adding liquids and paste-like materials to powders and particles. At the same time, due to the difficulty in cleaning viscous materials, they are suitable for mixing in situations where production is large and varieties are not frequently changed.

[0004] Horizontal ribbon mixers are usually used for mixing powders or particles, and their dynamic shaft seals generally use packing seals or mechanical seals. When the mixer is working, the dynamic shaft often produces large radial runout, and the internal medium easily enters the seal cavity along the gap, causing damage and corrosion to the bearings, affecting the stability and life of the mixer, and even causing leakage of the medium, bringing safety hazards to the company's production and increasing maintenance costs.

[0005] Therefore, there is an urgent need for a sealing device for sealing the motor shaft of a horizontal ribbon mixer to solve the problem of loose sealing of the motor shaft of the horizontal ribbon mixer.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0007] The purpose of the present invention is to provide a horizontal ribbon mixer and a magnetic fluid sealing device for sealing its moving shaft, which solves the problem of poor sealing of the sealing device of the existing horizontal ribbon mixer moving shaft, improves the performance of the magnetic fluid seal for the sealing of the horizontal ribbon mixer moving shaft, significantly extends the service life, and can further prevent powder intrusion under the action of gas purge, which can effectively solve the problem of poor sealing of the horizontal ribbon mixer moving shaft, and has high reliability and good stability.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a magnetic fluid sealing device for sealing the motor shaft of a horizontal ribbon mixer, which is installed on the main shaft inside the horizontal ribbon mixer, and the magnetic fluid sealing device comprises: a sleeve, which is sleeved on the main shaft; a sealing shell and a sealing seat, which are sequentially sleeved on the circumference of the sleeve, and the sealing seat is located at the end of the sleeve; two air holes are opened on the sealing shell, which are respectively recorded as the first air hole and the second air hole, and the first air hole and the second air hole are respectively installed with a ferrule joint and a plug, the ferrule joint is used to connect the first air hole with an external air source, and the plug is used to close the second air hole, and the first air hole is connected to the sealing shell and the sleeve. An annular contact space is formed at the contact point, and the annular contact space is connected to the interior of the sealing shell; an axial positioning component, which axially connects the sealing shell and the sealing seat; a magnetic fluid sealing component, which is sleeved on the shaft sleeve and is located inside the sealing shell, with a gap between it and the shaft sleeve, and the gaps between the left pole shoe and the right pole shoe and the shaft sleeve are filled with magnetic fluid; and a lip seal ring, which is arranged inside the sealing shell and is located between the magnetic fluid sealing component and the annular contact space, and its opening faces the magnetic fluid sealing component; wherein the first air hole, the second air hole, the ferrule joint, the plug and the annular contact space constitute a gas purge structure.

[0009] Preferably, the magnetic fluid sealing device further comprises: an elastomer component, which axially connects the sealing shell and the sealing seat, the relative surfaces of the sealing shell and the sealing seat are not in contact and a groove-shaped installation space is formed in the axial direction, and the elastomer component is fixed in the groove-shaped installation space.

[0010] More preferably, the elastic body assembly comprises: an annular rubber, an annular pressure plate and a first fastener; the annular rubber is located between the annular pressure plate and the surfaces opposite to the sealing housing and the sealing seat and is fixed by the first fastener.

[0011] Preferably, the axial positioning assembly comprises: a stud, a flat washer and a nut; the stud axially penetrates the sealing housing and the sealing seat and is fastened and connected by the nut and the flat washer.

[0012] Preferably, the magnetic fluid sealing assembly comprises: a left pole shoe, an annular permanent magnet, a right pole shoe and a magnetic fluid; a left pole shoe and a right pole shoe are respectively arranged on both sides of the annular permanent magnet, and a gap is left between the left pole shoe, the annular permanent magnet and the right pole shoe and the sleeve, and the gap is filled with magnetic fluid.

[0013] More preferably, a lip seal is provided on one side of the right pole shoe close to the sealing seat; or / and, pole teeth are provided on one side of the left pole shoe and the right pole shoe close to the sleeve, and the gap between the pole teeth and the sleeve is filled with the magnetic fluid; or / and, an O-ring is provided on one end of the right pole shoe close to the sealing shell.

[0014] More preferably, the gap between the pole teeth and the sleeve is 0.1-0.3 mm.

[0015] Preferably, a bearing is sleeved on the sleeve; or / and, two O-rings are arranged between the main shaft and the sleeve; or / and, the sealing shell and the sealing seat are both made of non-magnetic material; or / and, a drive sleeve is sleeved on the sleeve, and the drive sleeve is clamped against the other end of the sleeve to abut the main shaft against the sleeve.

[0016] More preferably, a cover plate is sleeved on the sleeve, and the cover plate is located between the sealing shell and the driving sleeve, a gap is left on the side of the cover plate close to the sleeve and they are not in contact, and the cover plate is fixedly connected to the sealing shell; a bearing is sleeved on the sleeve, and the outer ring of the bearing is clamped on the inner wall of the sealing shell; the bearing is located between the cover plate and the magnetic fluid sealing assembly, and its two ends are respectively clamped on the shoulders of the cover plate and the inner wall of the sealing shell, and a spacer is provided on the side of the bearing close to the magnetic fluid sealing assembly; a grease injection hole is opened on the cover plate, and the grease injection hole is connected to the lubricating oil groove of the bearing, so as to allow the lubricating oil to flow to the bearing; or / and, the driving sleeve comprises: two-petal rings and screws, the two-petal rings are sleeved on the sleeve and fixed together by screws to abut the main shaft against the sleeve.

[0017] Another object of the present invention is to provide a horizontal ribbon mixer containing the magnetic fluid sealing device, wherein the sealing seat is fixedly connected to the horizontal ribbon mixer body; an O-ring three is provided on the surface where the sealing seat contacts the horizontal ribbon mixer body.

[0018] The horizontal ribbon mixer and the magnetic fluid sealing device for the dynamic shaft seal of the present invention solve the problem of the existing horizontal ribbon mixer dynamic shaft seal device not being tightly sealed, and have the following advantages:

[0019] (1) The magnetic fluid sealing device of the present invention skillfully combines the magnetic fluid seal, gas purge seal and lip seal together. The three sealing structures have an influence on each other. During the relative rotation of the shaft sleeve and the sealing housing, the magnetic fluid seal seals the gap between the shaft sleeve and the sealing housing. During operation, the internal medium easily enters the sealing cavity along the gap, causing damage and corrosion to the bearing. The present invention forms a gas barrier through the gas purge seal, which can prevent powder from entering the interior of the sealing device and reduce the temperature rise caused by friction. Considering that a small amount of magnetic fluid in the magnetic fluid seal may pass through the gap to contaminate the medium in the machine and that the gas purge seal barrier does not completely block the powder, a lip seal is further provided between the gas purge structure and the magnetic fluid seal, thereby preventing a small amount of magnetic fluid from passing through the gap to contaminate the medium in the machine and further blocking the powder that is not completely blocked;

[0020] (2) The magnetic fluid sealing device of the present invention injects magnetic fluid into the gap between the pole tooth and the shaft sleeve. The magnetic circuit is composed of the shaft sleeve, the pole shoe and the annular permanent magnet. Under the action of the magnetic field generated by the annular permanent magnet, the magnetic fluid is highly concentrated and forms a liquid O-ring along the gap between the annular pole tooth and the shaft sleeve. When the magnetic fluid is subjected to the pressure difference, the magnetic fluid moves slightly in the non-uniform magnetic field, generating a magnetic force to resist the pressure difference, thereby reaching a new balance, and then blocking the gap between the pole tooth and the shaft sleeve.

[0021] (3) In order to improve the reliability of the magnetic fluid sealing device of the present invention, a gas purge structure is provided. The gas source is connected to the outside through a ferrule-type joint, and the other air hole is sealed with a plug. Since there is a magnetic fluid seal on the left side of the air passage and an annular contact surface on the right side, the air passage inside the air passage forms a gas barrier with a certain pressure. This has two advantages: first, it prevents a large amount of powder from entering the interior of the sealing device, and second, a small amount of gas will enter the annular contact surface to play a role in cooling;

[0022] (4) The magnetic fluid sealing device of the present invention, taking into account that the working process of the horizontal ribbon mixer is often accompanied by large radial runout, uses high-performance rubber to connect the sealing seat and the sealing housing together, and the high-performance rubber can play a buffering role, and uses studs and nuts to axially position the sealing housing and the sealing seat to ensure a certain structural strength;

[0023] (5) The magnetic fluid sealing device of the present invention improves the performance of magnetic fluid sealing for sealing the moving shaft of a horizontal ribbon mixer, significantly prolongs its service life, and can further prevent powder intrusion under the action of gas purge, and can effectively solve the problem of loose sealing of the moving shaft of a horizontal ribbon mixer, and has high reliability and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a schematic structural diagram of a magnetic fluid sealing device for sealing the motor shaft of a horizontal ribbon mixer.

[0025] Figure 2 For the present invention Figure 1 A partial enlarged view of middle A.

[0026] Figure 3 For the present invention Figure 1 A partial enlarged view of B.

[0027] Figure 4 For the present invention Figure 1 A partial enlarged view of C in the middle.

[0028] Figure 5 It is a schematic structural diagram of the shaft sleeve and the driving sleeve of the present invention.

[0029] Numbers: 1. Spindle; 2. Drive sleeve; 3. Bushing; 4. Cover plate; 5. Cardan joint; 6. Sealing housing; 7. Sealing seat; 8. Two hexagon socket head screws; 9. Lip seal; 10. Spacer; 11. Plug; 12. Bearing; 13. One hexagon socket head screw; 14. Grease injection hole; 15. Left pole shoe; 16. Annular permanent magnet; 17. One O-ring; 18. Right pole shoe; 19. Magnetic fluid; 20. Pole tooth; 21. Annular rubber; 22. Pressure plate; 23. Hexagon head bolt; 24. Stud; 25. Hexagon nut; 26. Flat washer; 27. Two O-rings; 28. Screw. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The features mentioned in the present invention can be combined arbitrarily, as long as there is no contradiction in the combination of these features, all possible combinations should be considered as the scope of this specification. Each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.

[0032] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The present invention provides a magnetic fluid sealing device for sealing a horizontal spiral belt mixer motor shaft, referring to Figures 1 to 5 The magnetic fluid sealing device is installed on the main shaft 1 inside the horizontal ribbon mixer, and comprises: a sleeve 3, a sealing shell 6, a sealing seat 7, an axial positioning assembly, a magnetic fluid sealing assembly and a lip seal 9. Among them, the sleeve 3 is sleeved on the main shaft 1, and the sleeve 3 is sleeved with a sealing shell 6 and a sealing seat 7 in sequence in the circumferential direction, and the sealing seat 7 is located at the end of the sleeve 3. The sealing shell 6 has two air holes, which are respectively recorded as the first air hole and the second air hole. The first air hole and the second air hole are respectively installed with a ferrule joint 5 and a plug 11. The ferrule joint 5 is used to connect the first air hole with an external air source, and the plug 11 is used to close the second air hole. The first air hole is connected to the contact point between the sealing shell 6 and the sleeve 3 to form an annular contact space, and the annular contact space is connected to the inside of the sealing shell 6. The axial positioning assembly is used to axially connect the sealing shell 6 and the sealing seat 7. The magnetic fluid sealing assembly is sleeved on the sleeve 3 and is located inside the sealing shell 6. There is a gap between it and the sleeve 3, and the gap is filled with magnetic fluid 19. The lip seal ring 9 is arranged inside the sealing housing 6 and between the magnetic fluid sealing component and the annular contact space, and its opening faces the magnetic fluid sealing component. The first air hole, the second air hole, the ferrule joint 5, the plug 11 and the annular contact space constitute a gas purge structure.

[0034] The present invention seals the moving shaft by magnetic fluid sealing, and the magnetic fluid 19 is highly concentrated and forms a liquid O-ring along the gap between the magnetic fluid sealing assembly and the sleeve 3. When the magnetic fluid 19 is subjected to the pressure difference, the magnetic fluid 19 moves slightly in the non-uniform magnetic field, generates a magnetic force against the pressure difference, thereby reaching a new balance, and then blocks the gap between the magnetic fluid sealing assembly and the sleeve 3. Considering that the horizontal ribbon mixer is usually used for powder or particle mixing, the moving shaft tends to produce a large radial runout when the mixer is working, and the internal medium easily enters the sealing cavity along the gap, resulting in damage and corrosion of the bearing. Therefore, on the basis of magnetic fluid sealing, the present invention designs a gas purge structure, and integrates the magnetic fluid sealing and the gas purge structure through a clever structural design. The annular contact space formed by the external gas source of the ferrule joint 5 and the sleeve 3 and the sealing shell 6 forms a gas barrier inside, and the gas purge structure can not only prevent a large amount of powder from entering the interior of the sealing device, but also a small amount of gas will enter the annular contact space to reduce the temperature rise caused by friction. In addition, considering that a small amount of magnetic fluid in the magnetic fluid seal may pass through the gap to contaminate the medium in the machine and that the gas purge seal barrier may not completely block the powder, the present invention designs a lip seal to combine the magnetic fluid seal, the gas purge structure and the lip seal. The lip seal is arranged between the magnetic fluid seal and the gas purge structure, thereby preventing the magnetic fluid from passing through the gap to contaminate the medium in the machine and further blocking the incompletely blocked powder.

[0035] In addition, during the research and development process, the inventors of the present invention also used some mechanical sealing structures such as brush seals and labyrinth seals to replace lip seals and / or gas purge seals. Considering the economy, processing, installation and sealing effect, the combination of lip seals and gas purge seals is better.

[0036] According to a further optimization scheme, the magnetic fluid sealing device of the present invention further comprises: an elastomer component, which axially connects the sealing shell 6 and the sealing seat 7, wherein the relative surfaces of the sealing shell 6 and the sealing seat 7 are not in contact with each other and a groove-shaped installation space is formed in the axial direction, and the elastomer component is fixed in the groove-shaped installation space.

[0037] Considering that the working process of the horizontal ribbon mixer is often accompanied by a large radial runout, an elastomer component is installed axially between the sealing shell 6 and the sealing seat 7 of the present invention, and the elastomer component plays a certain buffering role.

[0038] According to a further optimized solution, the elastomer assembly includes: an annular rubber 21 , an annular pressure plate 22 and a first fastener 23 ; the annular rubber 21 is located between the annular pressure plate 22 and the surfaces opposite to the sealing housing 6 and the sealing seat 7 and is fixed by the first fastener 23 .

[0039] The present invention places the pressing plate in close contact with the inner two walls of the annular rubber 21 and forms a "soft connection" between the sealing housing 6 and the sealing seat 7. The annular rubber 21 plays a buffering role, which can improve the sealing performance of the connection part.

[0040] Exemplarily, the axial cross-section of the annular rubber 21 is in the shape of a groove, and a plurality of through holes are opened on the inner walls of the groove. A plurality of first bolts 23 are cooperated to penetrate the two annular pressure plates 22 and the through holes of the annular rubber 21, and are fastened to the sealing shell 6 and the sealing seat 7 through the axial positioning assembly, so that the pressure plate is tightly attached to the inner walls of the annular rubber 21 and between the sealing shell 6 and the sealing seat 7.

[0041] Exemplarily, the first bolt 23 is a hexagonal bolt, and the through holes on the two inner walls of the groove are matched with a plurality of hexagonal bolts to penetrate through the through holes of the two annular pressure plates 22 and the annular rubber 21.

[0042] As a further optimization plan, the material of the annular rubber 21 is fluororubber, which not only ensures a certain hardness but also has corrosion resistance and can also meet the buffering requirements.

[0043] According to a further optimized solution, the axial positioning assembly includes a stud 24, a flat washer 26 and a nut 25. The stud 24 axially penetrates the sealing housing 6 and the sealing seat 7 and is fastened and connected by the nut 25 and the flat washer 26.

[0044] In the present invention, the sealing housing 6 and the sealing seat 7 are fixed together in the axial direction by means of the stud 24, the flat gasket 26 and the nut 25, thereby increasing the overall strength of the sealing device and ensuring the axial positioning.

[0045] Exemplarily, the nut 25 is a hexagonal nut.

[0046] Exemplarily, the axial positioning components are evenly distributed in the radial direction.

[0047] Further optimization scheme, the magnetic fluid sealing assembly includes: a left pole shoe 15, an annular permanent magnet 16, a right pole shoe 18 and a magnetic fluid 19. The left pole shoe 15 and the right pole shoe 18 are respectively arranged on both sides of the annular permanent magnet 16, and there is a gap between the left pole shoe 15, the annular permanent magnet 16 and the right pole shoe 18 and the shaft sleeve 3, and the gap between the left pole shoe 15 and the right pole shoe 18 and the shaft sleeve 3 is filled with magnetic fluid 19. The annular permanent magnet 16 acts as a magnetic source to provide magnetic force for the left pole shoe 15 and the right pole shoe 18.

[0048] As a further optimization solution, a lip seal ring 9 is provided on one side of the right pole shoe 18 close to the seal seat 7 .

[0049] As a further optimization solution, pole teeth 20 are provided on one side of the left pole shoe 15 and the right pole shoe 18 close to the shaft sleeve 3, and the gap between the pole teeth 20 and the shaft sleeve 3 is filled with magnetic fluid 19 to improve the sealing performance.

[0050] As a further optimization scheme, an O-ring 17 is provided at one end of the right pole shoe 18 close to the sealing housing 6 to improve the sealing performance and effectively reduce the possibility of powder leakage or intrusion.

[0051] Further optimization scheme, the gap between the pole tooth 20 and the sleeve 3 is 0.1 ~ 0.3mm. The sealing strength of the magnetic fluid is related to the gap. The size of the gap depends on the sealed medium and the size of the overall sealing device. It is not the bigger the better, nor the smaller the better. A good sealing effect can be achieved within this gap range, but it is not limited to this range, and can be analyzed specifically according to specific working conditions.

[0052] According to a further optimized solution, a bearing 12 is sleeved on the shaft sleeve 3 .

[0053] To further optimize the solution, an O-ring 27 is provided between the main shaft 1 and the sleeve 3 to improve the sealing performance and effectively reduce the possibility of powder leakage or intrusion.

[0054] According to a further optimization scheme, both the sealing shell 6 and the sealing seat 7 are made of non-magnetic conductive materials.

[0055] According to a further optimized solution, the drive sleeve 2 is sleeved on the shaft sleeve 3 , and the drive sleeve 2 is clamped on the other end of the shaft sleeve 3 to connect the main shaft 1 with the shaft sleeve 3 .

[0056] According to a further optimized solution, the drive sleeve 2 comprises: two-petal rings and screws. The two-petal rings are sleeved on the shaft sleeve 3 and fixed together by screws 28 to abut the main shaft 1 against the shaft sleeve 3.

[0057] Exemplarily, the screw 28 is a hexagon socket head screw, and the shaft sleeve 3 is fixed to the main shaft 1 by tightening the hexagon socket head screw on the driving sleeve 2 .

[0058] Further optimization scheme, the sleeve 3 is sleeved with a cover plate 4, and the cover plate 4 is between the sealing shell 6 and the driving sleeve 2, and the cover plate 4 is close to the sleeve 3. There is a gap and no contact, and the cover plate 4 is fixedly connected with the sealing shell 6; the sleeve 3 is sleeved with a bearing 12, and the outer ring of the bearing 12 is clamped on the inner wall of the sealing shell 6. The bearing 12 is between the cover plate 4 and the magnetic fluid sealing assembly, and its two ends are respectively clamped on the shoulders of the cover plate 4 and the inner wall of the sealing shell 6, and the side of the bearing 12 close to the magnetic fluid sealing assembly is provided with a spacer 10. The cover plate 4 is provided with a grease injection hole 14, which is connected to the lubricating oil groove of the bearing 12, so as to allow the lubricating oil to flow to the bearing 12, which is convenient for grease filling and maintenance.

[0059] Exemplarily, the cover plate 4 is fixed to the sealing housing 6 by means of a hexagon socket head screw 13 .

[0060] According to a further optimization scheme, both the sealed housing 6 and the sealed housing 7 are made of non-magnetic conductive materials.

[0061] The method for using the magnetic fluid sealing device for sealing the motor shaft of a horizontal ribbon mixer of the present invention is as follows:

[0062] The sealing seat 7 of the magnetic fluid sealing device for sealing the shaft of the horizontal ribbon mixer of the present invention is fixedly connected to the horizontal ribbon mixer body by a hexagon socket head screw 2 8, and an O-ring 3 is provided on the contact surface between the sealing seat 7 and the horizontal ribbon mixer body.

[0063] In the magnetic fluid sealing device for sealing the shaft of a horizontal spiral belt mixer of the present invention, the main shaft 1 drives the sleeve 3 to rotate together during the rotation process, the sealing shell 6 and the sealing seat 7 rotate relative to the sleeve 3, and the magnetic fluid sealing assembly, the lip seal ring 9 and the gas purge structure together play a sealing role.

[0064] The magnetic fluid 19 is injected into the gap between the pole teeth 20 and the sleeve 3. The magnetic circuit is composed of the sleeve 3, the pole shoe and the annular permanent magnet 16. Under the action of the magnetic field generated by the annular permanent magnet 16, the magnetic fluid 19 is highly concentrated and forms a liquid O-ring along the gap between the pole teeth 20 and the sleeve 3. When the magnetic fluid 19 is subjected to the pressure difference, the magnetic fluid 19 moves slightly in the non-uniform magnetic field, generating a magnetic force to resist the pressure difference, thereby reaching a new balance, and then blocking the gap between the pole teeth 20 and the sleeve 3.

[0065] A set of gas purge structure is also provided in the magnetic fluid sealing device of the present invention to improve the reliability of the magnetic fluid sealing device. An external gas source is connected through a ferrule joint 5, and another air hole is closed by a plug 11. Since there is a magnetic fluid seal on the left side of the airway and an annular contact surface on the right side, the airway inside the airway forms a gas barrier with a certain pressure. This has two advantages: one is to prevent a large amount of powder from entering the inside of the sealing device, and the other is that a small amount of gas will enter the annular contact surface to play a cooling effect. Before use, according to specific working conditions, the influence of different gas pressures on the sealing effect is measured. While ensuring the formation of a protective effect, it is also necessary to avoid destroying the sealing effect of the magnetic fluid, and then clarify the pressure range of the blown gas that needs to be controlled during actual use.

[0066] A lip seal is provided between the gas purge component and the magnetic fluid seal to prevent a small amount of magnetic fluid 19 from passing through the gap and contaminating the medium in the machine.

[0067] The working process of the horizontal ribbon mixer is often accompanied by large radial runout. The high-performance annular rubber 21 is used to connect the sealing seat and the sealing shell together to play a buffering role. The stud 24 and the hexagonal nut 25 are used to axially position the sealing shell 6 and the sealing seat 7 to ensure a certain structural strength.

[0068] In summary, the present invention improves the performance of magnetic fluid seal for sealing the moving shaft of a horizontal ribbon mixer, significantly extends its service life, and can further prevent powder intrusion under the action of gas purge, and can effectively solve the problem of loose sealing of the moving shaft of a horizontal ribbon mixer, with high reliability and good stability.

[0069] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A magnetic fluid sealing device for sealing the shaft of a horizontal ribbon mixer, which is installed on the main shaft (1) inside the horizontal ribbon mixer, characterized in that: The magnetic fluid sealing device comprises: A shaft sleeve (3) sleeved on the main shaft (1); A sealing shell (6) and a sealing seat (7), which are sequentially sleeved on the circumference of the shaft sleeve (3), and the sealing seat (7) is located at the end of the shaft sleeve (3); the sealing shell (6) is provided with two air holes, which are respectively referred to as a first air hole and a second air hole, and the first air hole and the second air hole are respectively installed with a ferrule-type joint (5) and a plug (11), the ferrule-type joint (5) is used to connect the first air hole with an external air source, and the plug (11) is used to close the second air hole, and the first air hole is connected to the contact point between the sealing shell (6) and the shaft sleeve (3) to form an annular contact space, and the annular contact space is connected to the inside of the sealing shell (6); An axial positioning assembly axially connecting the sealing housing (6) and the sealing seat (7); a magnetic fluid sealing assembly, which is sleeved on the shaft sleeve (3) and is located inside the sealing housing (6), with a gap between the magnetic fluid sealing assembly and the shaft sleeve (3), and the gap is filled with a magnetic fluid (19); and A lip seal ring (9) is arranged inside the sealing housing (6) and between the magnetic fluid seal component and the annular contact space, with its opening facing the magnetic fluid seal component; The first air hole, the second air hole, the ferrule joint (5), the plug (11) and the annular contact space constitute a gas purge structure.

2. The magnetic fluid sealing device according to claim 1, characterized in that: The magnetic fluid sealing device also includes: An elastomer component axially connects the sealing shell (6) and the sealing seat (7); the relative surfaces of the sealing shell (6) and the sealing seat (7) are not in contact with each other and a groove-shaped installation space is formed in the axial direction; the elastomer component is fixed in the groove-shaped installation space.

3. The magnetic fluid sealing device according to claim 2, characterized in that: The elastic body assembly comprises: an annular rubber (21), an annular pressure plate (22) and a first fastener (23); The annular rubber (21) is located between the annular pressure plate (22) and the surfaces opposite to the sealing housing (6) and the sealing seat (7), and is fixed by the first fastener (23).

4. The magnetic fluid sealing device according to claim 1, characterized in that: The axial positioning assembly comprises: a stud (24), a flat washer (26) and a nut (25); The stud bolt (24) axially penetrates the sealing housing (6) and the sealing seat (7) and is fastened and connected by a nut (25) and a flat gasket (26).

5. The magnetic fluid sealing device according to claim 1, characterized in that: The magnetic fluid sealing assembly comprises: a left pole shoe (15), an annular permanent magnet (16), a right pole shoe (18) and a magnetic fluid (19); A left pole shoe (15) and a right pole shoe (18) are respectively arranged on both sides of the annular permanent magnet (16); a gap is left between the left pole shoe (15), the annular permanent magnet (16), the right pole shoe (18) and the shaft sleeve (3); and a magnetic fluid (19) is filled in the gap between the left pole shoe (15), the right pole shoe (18) and the shaft sleeve (3).

6. The magnetic fluid sealing device according to claim 5, characterized in that: A lip seal ring (9) is provided on one side of the right pole shoe (18) close to the seal seat (7); or / and, the left pole shoe (15) and the right pole shoe (18) are provided with pole teeth (20) on one side close to the shaft sleeve (3), and the gap between the pole teeth (20) and the shaft sleeve (3) is filled with the magnetic fluid (19); Or / and, an O-ring (17) is provided at one end of the right pole shoe (18) close to the sealing housing (6).

7. The magnetic fluid sealing device according to claim 6, characterized in that: The gap between the pole teeth (20) and the shaft sleeve (3) is 0.1 to 0.3 mm.

8. The magnetic fluid sealing device according to claim 1, characterized in that: The shaft sleeve (3) is sleeved with a bearing (12); Or / and, an O-ring 2 (27) is provided between the main shaft (1) and the shaft sleeve (3); Or / and, the sealing housing (6) and the sealing seat (7) are both made of non-magnetic conductive materials; Or / and, a drive sleeve (2) is sleeved on the shaft sleeve (3), and the drive sleeve (2) is clamped on the other end of the shaft sleeve (3) to make the main shaft (1) abut against the shaft sleeve (3).

9. The magnetic fluid sealing device according to claim 8, characterized in that: The shaft sleeve (3) is sleeved with a cover plate (4), and the cover plate (4) is located between the sealing shell (6) and the driving sleeve (2), a gap is left on the side of the cover plate (4) close to the shaft sleeve (3) and the cover plate (4) is not in contact, and the cover plate (4) and the sealing shell (6) are fixedly connected together; the shaft sleeve (3) is sleeved with a bearing (12), and the outer ring of the bearing (12) is clamped on the inner wall of the sealing shell (6); the bearing (12) is located between the cover plate (4) and the magnetic fluid sealing component, and the two ends of the bearing (12) are respectively clamped on the shoulders of the cover plate (4) and the inner wall of the sealing shell (6), and a spacer ring (10) is provided on the side of the bearing (12) close to the magnetic fluid sealing component; a grease injection hole (14) is opened on the cover plate (4), and the grease injection hole (14) is communicated with the lubricating oil groove of the bearing (12) to allow the lubricating oil to flow to the bearing (12); Or / and, the drive sleeve (2) comprises: two-petal rings and screws, the two-petal rings are sleeved on the shaft sleeve (3) and fixed together by screws (28) to abut the main shaft (1) against the shaft sleeve (3).

10. A horizontal ribbon mixer comprising a magnetic fluid sealing device as claimed in any one of claims 1 to 9, characterized in that: The sealing seat (7) is fixedly connected to the horizontal ribbon mixer body; an O-ring three is provided on the surface of the sealing seat (7) in contact with the horizontal ribbon mixer body.

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