Magnetic fluid seal device with gas barrier

Abstract

The application discloses a magnetic liquid sealing device using gas isolation, which comprises a shell, a rotating shaft, at least one pole shoe and a centrifugal compressor. The side of the pole shoe close to the sealed container is provided with a first gas flow cavity, the first gas flow cavity is communicated with each of a first gas outlet and a first exhaust hole, the centrifugal compressor is installed in an installation cavity, the centrifugal compressor comprises an impeller provided with a plurality of blades, the impeller is connected with the rotating shaft and rotates with the rotating shaft, and the impeller blows gas to the first gas flow cavity through the first gas outlet. The centrifugal compressor installed in the installation cavity in the rotating shaft generates gas with a certain pressure through the rotation of the rotating shaft, so that the sealed medium and the magnetic liquid are separated, the problem of instability at the contact interface of two liquids when the liquid medium is sealed is effectively solved, the sealing reliability is improved, and the service life of the device is prolonged.

Description

Technical Field

[0001] This invention relates to the field of magnetic liquid sealing technology, and in particular to a magnetic liquid sealing device that utilizes gas isolation. Background Technology

[0002] Magnetic fluid sealing technology boasts advantages such as zero leakage, no wear, long lifespan, and simple structure, leading to its increasing adoption across various industries. However, in related technologies, when magnetic fluids seal liquid media, the instability at the interface between the two liquids makes the magnetic fluid highly susceptible to miscibility with the sealed liquid medium, resulting in seal failure. High-pressure, high-velocity environments not only exacerbate the instability at the liquid-liquid interface between the magnetic fluid and the sealed liquid medium, but also facilitate emulsification between the sealing and sealed liquids, leading to a decline in the magnetic fluid's performance and ultimately, seal failure. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of the present invention propose a magnetic liquid sealing device utilizing gas isolation.

[0004] The present invention discloses a gas-isolated magnetic liquid sealing device, comprising: a housing having a chamber therein, and a first vent hole communicating with the chamber; a rotating shaft passing through the chamber, having a mounting cavity inside, and having a vent for connecting the mounting cavity to the outside and a first vent hole for connecting the mounting cavity to the chamber; at least one pole shoe fitted onto the rotating shaft and located within the chamber, the pole shoe having a plurality of pole teeth spaced apart axially along the rotating shaft on its inner side, forming a sealing gap between the pole teeth and the outer circumferential surface of the rotating shaft, the sealing gap containing magnetic liquid, and a first gas flow cavity on the side of the pole shoe adjacent to the sealed container, the first gas flow cavity communicating with each of the first vent hole and the first exhaust hole; and a centrifugal compressor installed within the mounting cavity, the centrifugal compressor including an impeller with a plurality of blades, the impeller being connected to the rotating shaft and rotating with the rotating shaft, the impeller blowing air into the first gas flow cavity through the first vent hole.

[0005] The magnetic liquid sealing device provided in this embodiment of the invention uses a centrifugal compressor installed in the mounting cavity inside the rotating shaft. The rotation of the shaft generates gas at a certain pressure, which separates the medium to be sealed from the magnetic liquid. This effectively solves the problem of instability at the interface between the two liquids when sealing the liquid medium, improves sealing reliability, increases the service life of the device, eliminates the need for an external gas storage tank, saves energy, and the centrifugal compressor does not occupy the axial installation space inside the housing, making it suitable for sealing devices with high requirements for axial space.

[0006] In some embodiments, there are multiple impellers, which are spaced apart axially on the shaft, and the first air outlet is connected to the air outlet end of the most downstream impeller.

[0007] In some embodiments, the diameter of the impeller gradually increases along the direction adjacent to the sealed container, a plurality of blades are spaced apart in the circumferential direction of the impeller, an airflow channel is formed between two adjacent blades, and the width of the airflow channel gradually increases along the direction adjacent to the sealed container.

[0008] In some embodiments, the centrifugal compressor includes a diffuser connected to and rotating with the impeller. The diffuser includes a plurality of diffuser blades located outside the blades of the impeller and spaced apart around the impeller. The flow area of ​​the flow channel between two adjacent diffuser blades gradually increases outward.

[0009] In some embodiments, the magnetic liquid sealing device includes a filter element disposed at the vent and / or the first vent.

[0010] In some embodiments, the pole shoe includes a first pole shoe and a second pole shoe, the permanent magnet is located axially between the first pole shoe and the second pole shoe and abuts against each of the first pole shoe and the second pole shoe, the first pole shoe is adjacent to the sealed container relative to the second pole shoe, and the first gas flow chamber is located on the side of the first pole shoe adjacent to the sealed container.

[0011] In some embodiments, the magnetic liquid sealing device further includes: a first bearing located in the cavity and supported between the housing and the rotating shaft; a second bearing located in the cavity and supported between the housing and the rotating shaft, wherein the first pole shoe, the second pole shoe and the permanent magnet are located axially on the rotating shaft between the first bearing and the second bearing, and the first bearing is adjacent to the sealed container relative to the second bearing;

[0012] The first gas flow cavity is formed between the first pole shoe and the first bearing; or, the first gas flow cavity is located on the side of the first bearing adjacent to the sealed container.

[0013] In some embodiments, there are multiple first vent holes, which are spaced apart in the circumferential direction of the rotating shaft; and / or, there are multiple first exhaust holes, which are spaced apart in the circumferential direction of the rotating shaft on the peripheral wall of the housing.

[0014] In some embodiments, the side of the pole shoe away from the sealed container has a second gas flow chamber, the housing is provided with a second exhaust port communicating with the second gas flow chamber, the rotating shaft is provided with a second vent port communicating with the mounting cavity and the second gas flow chamber, the second vent port is located upstream of the first vent port, the centrifugal compressor also blows air into the second gas flow chamber through the second vent port, and the magnetic liquid sealing device includes a first filter element, which is disposed at the vent.

[0015] In some embodiments, the magnetic liquid sealing device includes a second filter element disposed at the first vent and / or the second vent. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the internal structure of the magnetic liquid sealing device according to an embodiment of the present invention.

[0017] Figure 2 This is a front view of the centrifugal compressor according to an embodiment of the present invention.

[0018] Figure 3 yes Figure 1 Cross-sectional view at point AA.

[0019] Figure 4 This is a schematic diagram of a centrifugal compressor in another embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the internal structure of a magnetic liquid sealing device according to another embodiment of the present invention.

[0021] Figure label:

[0022] Magnetic liquid sealing device 100

[0023] Housing 1, Chamber 11, First vent 12, Outer shell 13, End cap 14, Second connecting hole 141, Second vent 15, Rotating shaft 2, Mounting cavity 21, Vent 22, First vent 23, Second vent 24

[0024] 3. First pole shoe 31, second pole shoe 32, pole tooth 33, magnetic fluid 34, first gas flow chamber 35, second gas flow chamber 36.

[0025] Centrifugal compressor 4, impeller 41, first impeller 41a, second impeller 41b, blades 411, first diffuser blade 42, second diffuser blade 43.

[0026] First filter element 51, second filter element 52

[0027] Permanent magnet 6.

[0028] First bearing 71, second bearing 72, first sleeve 81, first connecting hole 811, second sleeve 82, elastic retaining ring 9, and fastener 10. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] The following is based on Figures 1-5 The magnetic liquid sealing device 100 according to an embodiment of the present invention includes: a housing 1, a rotating shaft 2, at least one pole shoe 3, and a centrifugal compressor 4.

[0031] The housing 1 has a chamber 11 inside, and the housing 1 is provided with an exhaust port 12 communicating with the chamber 11. The rotating shaft 2 passes through the chamber 11 and is rotatable relative to the housing 1, with both ends of the rotating shaft 2 extending from both sides of the chamber 11. The rotating shaft 2 is provided with a mounting cavity 21, and the rotating shaft 2 is provided with a vent 22 and an exhaust port 23. The vent 22 is used to connect the mounting cavity 21 to the outside, and the exhaust port 23 is used to connect the mounting cavity 21 to the chamber 11.

[0032] The pole shoe 3 is fitted onto the rotating shaft 2 and located within the chamber 11. The pole shoe 3 is connected to the housing 1. The inner circumferential surface of the pole shoe 3 is provided with multiple pole teeth 33 spaced apart along the axial direction of the rotating shaft 2. A tooth groove is formed between adjacent pole teeth 33, and a sealing gap is formed between the pole teeth 33 and the outer circumferential surface of the rotating shaft 2. The pole teeth 33 are magnetic, and a magnetic liquid 34 is adsorbed within the sealing gap. The magnetic liquid 34 is adsorbed onto the tooth tip surface of the pole teeth 33 and contacts the outer circumferential surface of the rotating shaft 2, thereby achieving a sealing effect.

[0033] The side of the pole shoe 3 adjacent to the sealed container has a first gas flow chamber 35, the sealed container being used to contain the sealed substance, for example, Figure 1 The sealed container is connected to the left side of the housing 1. The housing 1 is provided with a first exhaust port 12 that communicates with the first gas flow chamber 35, and the rotating shaft 2 is provided with a first air outlet 23 that communicates with the mounting cavity 21 and the first gas flow chamber 35.

[0034] Centrifugal compressor 4 is installed in mounting cavity 21. Centrifugal compressor 4 includes impeller 41, impeller 41 is provided with multiple blades 411. Impeller 41 is connected to rotating shaft 2 and rotates with rotating shaft 2. Impeller 41 blows air into first gas flow cavity 35 through first air outlet 23.

[0035] The rotation of the shaft 2 drives the impeller 41 to rotate. Gas enters the mounting cavity 21 from the vent 22 of the shaft 2. Under the centrifugal force of the impeller 41, the gas is thrown to the outer edge. The gas flow with a certain pressure and velocity is discharged from the exhaust end of the centrifugal compressor 4 and blown into the first gas flow cavity 35 through the first exhaust hole 23. A gas isolation layer with a certain pressure is formed in the first gas flow cavity 35. The gas in the gas isolation layer can be discharged from the first exhaust hole 12. The gas flowing in the first gas flow cavity 35 isolates the sealed substance in the sealed container from the magnetic liquid. The magnetic liquid sealing device provided in this embodiment of the invention uses a centrifugal compressor installed in the mounting cavity inside the shaft. The rotation of the shaft generates a certain pressure of gas, which separates the sealed medium and the magnetic liquid. This can effectively solve the problem of instability at the interface between the two liquids when sealing the liquid medium, improve the sealing reliability, increase the service life of the device, eliminate the need for an external gas tank, save energy, and the centrifugal compressor does not occupy the axial installation space inside the housing, making it suitable for sealing devices with high axial space requirements.

[0036] For ease of description, the following will use... Figure 1 and Figure 5 Taking the rotating shaft 2, which extends axially in the left-right direction in the magnetic liquid sealing device 100 shown, as an example, the magnetic liquid sealing device 100 of this embodiment of the invention is described. The air inlet end of the centrifugal compressor 4 is its right end, and the air outlet end of the centrifugal compressor 4 is its left end. The first air outlet 23 of the rotating shaft 2 is connected to the air outlet end of the centrifugal compressor 4.

[0037] The following is based on Figures 1-3 A magnetic liquid sealing device 100 is described in a specific embodiment of the present invention.

[0038] like Figure 1 and Figure 2 As shown, the diameter of the impeller 41 gradually increases along the direction adjacent to the sealed container, and multiple blades 411 are spaced apart in the circumferential direction of the impeller 41. An airflow channel is formed between two adjacent blades 411, and the cross-section of the airflow channel gradually increases along the direction adjacent to the sealed container.

[0039] Gas enters the mounting cavity 21 from the vent 22 of the rotating shaft 2. After passing through the impeller 41, the gas is subjected to the centrifugal force of the impeller 41 and flows to the left along the airflow channel between the blades 411 while being thrown to the outer edge. At the same time, as the cross-section of the airflow channel gradually expands, the relative velocity of the gas decreases, kinetic energy is converted into pressure energy, and the pressure of the gas is increased. This increases the pressure of the gas isolation layer in the gas flow cavity 35, making the isolation effect of the gas isolation layer better.

[0040] In some embodiments, the centrifugal compressor 4 includes a diffuser connected to and rotating with the impeller 41. The diffuser is configured to increase the pressure of the airflow.

[0041] Specifically, such as Figure 4 As shown, the diffuser includes multiple first diffuser blades 42, which are located outside the blades 411 of the impeller 41 and spaced apart around the impeller 41. The flow area of ​​the flow channel between two adjacent first diffuser blades 42 gradually increases outward. After the gas flows out from the outer edge of the airflow channel of the impeller 41, it enters the flow channel between the first diffuser blades 42. Due to the gradual increase in the flow area of ​​the flow channel, the absolute velocity of the gas decreases, kinetic energy is converted into pressure energy, and the gas pressure further increases. This further increases the pressure of the gas isolation layer in the gas flow cavity 35, making the isolation effect of the gas isolation layer better.

[0042] like Figure 4 As shown, the diffuser also includes a plurality of second diffuser blades 43 located outside the first diffuser blade 42 and spaced around the impeller 41. The second diffuser blades 43 rotate with the rotation of the first diffuser blade 42. The gas discharged from the flow channel between the first diffuser blades 42 is further diffused by the second diffuser blades 43, and the pressure of the gas can be further increased.

[0043] It should be noted that the structure of the diffuser is not limited to this, and can be any of the common diffusers known to those skilled in the art.

[0044] like Figure 1 As shown, the magnetic liquid sealing device 100 has two pole shoes 3, including a first pole shoe 31 and a second pole shoe 32. The first pole shoe 31 and the second pole shoe 32 are spaced apart axially on the rotating shaft 2. The first pole shoe 31 is located to the left of the second pole shoe 32 and is relatively close to the sealed container. The first gas flow chamber 35 is located on the side of the first pole shoe 31 that is close to the sealed container, that is, to the left of the first pole shoe 31. Furthermore, both the first pole shoe 31 and the second pole shoe 32 are annular, with their outer circumferences connected to the housing 1 and relatively stationary with respect to the housing 1. When the rotating shaft 2 rotates, relative movement occurs between the rotating shaft 2 and the first pole shoe 31 and the second pole shoe 32. The magnetic liquid is maintained in the sealing gap between the first pole shoe 31 and the rotating shaft 2, and in the sealing gap between the second pole shoe 32 and the rotating shaft 2.

[0045] The magnetic liquid sealing device 100 includes a permanent magnet 6, which is located axially between the first pole piece 31 and the second pole piece 32 of the rotating shaft 2. The first pole piece 31 and the second pole piece 32 are made of magnetically conductive material. The magnetic field lines of the permanent magnet 6 pass through the first pole piece 31 and the second pole piece 32, so that both the first pole piece 31 and the second pole piece 32 are magnetic. As a result, the magnetic liquid 34 used for sealing can be adsorbed at the pole teeth 33 of the first pole piece 31 and the second pole piece 32.

[0046] Specifically, the permanent magnet 6 has a first end (left end) and a second end (right end) opposite each other along the axial direction of the rotating shaft 2. The first end of the permanent magnet 6 abuts against the first pole piece 31, making the first pole piece 31 magnetic. The second end of the permanent magnet 6 abuts against the second pole piece 32, making the second pole piece 32 magnetic. In other words, a magnetic circuit is formed between the permanent magnet 6, the first pole piece 31, the second pole piece 32, and the rotating shaft 2. Under the action of the magnetic field, the magnetic fluid is adsorbed into the sealed gap.

[0047] Optionally, the permanent magnet 6 is ring-shaped, or the permanent magnet 6 is a plurality of permanent magnet blocks arranged sequentially around the circumference of the rotating shaft 2, and each permanent magnet block abuts against each of the first pole piece 31 and the second pole piece 32 to provide magnetism to the pole piece 3.

[0048] In other alternative embodiments, the number of pole shoes 3 and their arrangement with the permanent magnets 6 can be different, and the present invention does not limit this.

[0049] Furthermore, such as Figure 1 As shown, the magnetic liquid sealing device 100 further includes a first bearing 71, a second bearing 72, a first sleeve 81, a second sleeve 82, and an elastic retaining ring 9. The first bearing 71, the second bearing 72, the first sleeve 81, the second sleeve 82, and the elastic retaining ring 9 are all located within the chamber 11 of the housing 1. The first bearing 71 and the second bearing 72 are both supported between the housing 1 and the rotating shaft 2, supporting the rotation of the rotating shaft 2 relative to the housing 1. Each of the first pole shoe 31, the permanent magnet 6, and the second pole shoe 32 is located axially between the first bearing 71 and the second bearing 72 on the rotating shaft 2.

[0050] exist Figure 1 In the example shown, the second bearing 72 is located to the right of the first bearing 71, and the first bearing 71 is adjacent to the sealed container relative to the second bearing 72. The first gas flow chamber 35 is located between the first bearing 71 and the first pole shoe 31. The first gas flow chamber 35 is annular, and the gas isolation layer with a certain pressure in the first gas flow chamber 35 effectively isolates the sealed medium and the magnetic liquid, protects the magnetic liquid from the influence of the sealed liquid medium, and extends its service life.

[0051] In other alternative embodiments, the first gas flow chamber 35 may be located on the side of the first bearing 71 adjacent to the sealed container.

[0052] exist Figure 1 In the example shown, there are multiple first air outlets 23, which are spaced apart circumferentially on the rotating shaft 2. The first air outlets 23 extend radially along the rotating shaft 2, with their inner ends communicating with the outlet end of the centrifugal compressor 4 and their outer ends communicating with the first gas flow chamber 35. The arrangement of multiple first air outlets 23 allows the airflow discharged from the outlet end of the centrifugal compressor 4 to be evenly introduced into the annular first gas flow chamber 35, forming a more uniform gas isolation layer within the first gas flow chamber 35, effectively isolating the sealed liquid medium from the magnetic liquid.

[0053] exist Figure 1 In the example shown, there are multiple first exhaust holes 12, which are spaced apart on the peripheral wall of the housing 2 in the circumferential direction of the rotating shaft 2. The arrangement of multiple first exhaust holes 12 helps to smoothly discharge the airflow in the first gas flow chamber 35 and maintain unobstructed airflow.

[0054] like Figure 1 As shown, the first sleeve 81 is axially supported between the first pole shoe 31 and the first bearing 71 on the rotating shaft 2, and the first sleeve 81 is made of a non-magnetic material. The second sleeve 82 is axially supported between the second pole shoe 32 and the second bearing 72 on the rotating shaft 2, and the second sleeve 82 is also made of a non-magnetic material. The arrangement of the first sleeve 81 and the second sleeve 82 prevents the first bearing 71 and the second bearing 72 from affecting the magnetic field and causing magnetic field leakage. The first sleeve 81 is provided with a first connecting hole 811 that is opposite to and communicates with the first exhaust hole 12.

[0055] like Figure 1 As shown, the dustproof magnetic liquid sealing device 100 includes a fixing member 10, which is located in the mounting cavity 21 and connected to the wall of the mounting cavity 21. The central shaft of the impeller 41 is connected to the fixing member 10 so that the rotation of the rotating shaft 2 can drive the impeller 41 to rotate.

[0056] The elastic retaining ring 9 is sleeved on the rotating shaft 2 and abuts against the left end face of the first bearing 71 to limit the axial position of the first bearing 71 on the rotating shaft 2.

[0057] Furthermore, to facilitate the installation of the aforementioned components into the cavity 11 of the housing 1, such as... Figure 1 As shown, the housing 1 of the magnetic liquid sealing device 100 includes an outer shell 13 and an end cap 14. The outer shell 13 has a first end opposite to the rotating shaft 2 in the axial direction (e.g., Figure 1 (left end) and second end (e.g.) Figure 1 The right end of the outer casing 13 is connected to the sealed container (e.g., the first end of the outer casing 13). Figure 1 The sealed container is connected to the left end of the outer casing 13, and the second end of the outer casing 13 is sealed by the end cap 14.

[0058] exist Figure 1 In the illustrated embodiment, the centrifugal compressor 4 has one impeller 41. In other embodiments, there may be multiple impellers 41, which are spaced apart axially on the shaft. The first outlet 23 is connected to the outlet end of the downstream impeller 4. Gas enters the mounting cavity 21 from the vent 22 and is accelerated and pressurized in multiple stages by passing through multiple impellers 41. As a result, the gas discharged from the first outlet 23 into the first gas flow cavity 35 has a higher pressure and flow rate, which improves the isolation effect of the gas isolation layer in the first gas flow cavity 35.

[0059] Furthermore, the magnetic liquid sealing device 100 may also include a filter element disposed at the vent 22 to filter the gas entering the mounting cavity 21 and prevent external dust from entering the first gas flow cavity 35. The filter element may also be disposed at the first vent 23 for further filtering of dust in the airflow.

[0060] In related technologies, when magnetic fluid seals are used in dusty environments, dust can easily enter the gap between the magnetic fluid and the magnetic field, affecting the stability and sealing performance of the magnetic fluid.

[0061] The following is based on Figure 5 A magnetic liquid sealing device 100 is described in another specific embodiment of the present invention.

[0062] exist Figure 5 In the illustrated embodiment, the arrangement of the internal components of the magnetic liquid sealing device 100 can be referred to Figure 1 The embodiments shown are not described in detail here.

[0063] The side of the pole shoe 3 furthest from the sealed container has a second gas flow chamber 36, i.e., the second gas flow chamber 36 is located to the right of the second pole shoe 32. The housing 1 has a second exhaust port 15 communicating with the second gas flow chamber 36, and the rotating shaft 2 has a second vent port 24 communicating with the mounting cavity 21 and the second gas flow chamber 36. The second vent port 24 is located upstream of the first vent port 23, and the centrifugal compressor 4 also blows air into the second gas flow chamber 36 through the second vent port 24. A gas isolation layer with a certain pressure is formed in the second gas flow chamber 36, separating dust from the magnetic liquid in the environment. Furthermore, the gas in the second gas flow chamber 36 is in a circulating state, which can promptly discharge any dust that may enter, achieving zero dust pollution.

[0064] Specifically, such as Figure 5As shown, the centrifugal compressor 4 has two impellers 41: a first impeller 41a and a second impeller 41b. The first impeller 41a is located upstream of the second impeller 41b, and the second outlet 24 is located upstream of the first outlet 23. The second outlet 24 is connected to the outlet end of the first impeller 41a and is located between the first impeller 41a and the second impeller 41b. The first outlet 23 is connected to the outlet end of the second impeller 41b. Gas enters the mounting cavity 21 through the vent 22, and is first pressurized and accelerated by the first impeller 41a. Part of the airflow enters the second gas flow cavity 36 through the second outlet 24, and the other part flows towards the inlet end of the second impeller 41b. After being pressurized and accelerated twice by the second impeller 41b, the airflow enters the first gas flow cavity 35 through the first outlet 23.

[0065] In other alternative embodiments, the centrifugal compressor 4 may also have one impeller 41. The first outlet 23 and the second outlet 24 are both located downstream of the outlet end of the impeller 41. Part of the gas discharged from the impeller 41 enters the second gas flow chamber 36 through the second outlet 24, and the other part of the gas enters the first gas flow chamber 35 through the first outlet 23.

[0066] Furthermore, the magnetic liquid sealing device 100 also includes a first filter element 51, which is disposed at the air inlet of the mounting cavity 21, i.e., at the air vent 22. The first filter element 51 is used to filter the gas entering the first gas flow cavity 35 and the second gas flow cavity 36, preventing external dust from entering the first gas flow cavity 35 and the second gas flow cavity 36.

[0067] The magnetic liquid sealing device of this embodiment can effectively solve the problem that dust can easily contaminate the magnetic liquid when the magnetic liquid seal is used in a dusty environment, thereby improving the sealing reliability and increasing the service life of the device.

[0068] exist Figure 5 In the example shown, the first filter 51 is located at the vent 22 to preliminarily filter dust from the external environment, preventing a large amount of dust from entering the mounting cavity 21. The magnetic liquid sealing device also includes a second filter 51, which is located at the first vent 23 and the second vent 24. The second filter 52 is used to further filter dust in the airflow, preventing dust from entering the first gas flow cavity 35 and the second gas flow cavity 36.

[0069] Optionally, the first filter element 51 and the second filter element 52 are filter cotton or other breathable materials that can perform filtering functions.

[0070] Optionally, the second filter element 51 is disposed at the first air outlet 23, or the second filter element 51 is disposed at the second air outlet 24.

[0071] like Figure 5 As shown, the second gas flow chamber 36 is located on the right side of the second bearing 72. The second gas flow chamber 36 is annular and has a gas isolation layer with a certain pressure to effectively isolate external dust, protect the bearing and magnetic fluid from dust, and extend service life.

[0072] like Figure 5 As shown, a portion of the end cap 14 extends from the second end of the housing 13 and abuts against the second bearing 72 to limit the axial position of the second bearing 72 on the rotating shaft 2. The portion of the end cap 14 is provided with a second connecting hole 141 that is opposite to and communicates with the second vent hole 15.

[0073] Multiple second air outlets 24 are arranged at intervals along the circumference of the rotating shaft 2. This arrangement allows the airflow discharged from the centrifugal compressor 4 to be evenly introduced into the annular second gas flow chamber 36, forming a more uniform gas isolation layer within the chamber and effectively isolating external dust. Multiple second exhaust ports 15 are also arranged at intervals along the circumference of the rotating shaft 2 on the peripheral wall of the housing 2. This arrangement facilitates the smooth discharge of airflow from the second gas flow chamber 36, maintaining unobstructed airflow.

[0074] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0076] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0077] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0078] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A magnetic liquid sealing device utilizing gas isolation, characterized in that, include: A housing having a chamber inside, and a first vent hole communicating with the chamber on the housing; A rotating shaft passes through the chamber, and the rotating shaft has an installation cavity inside. The rotating shaft has a vent for connecting the installation cavity with the outside and a first vent for connecting the installation cavity with the chamber. At least one pole shoe is provided, which is fitted onto the rotating shaft and located in the cavity. The inner side of the pole shoe is provided with a plurality of pole teeth spaced apart in the axial direction of the rotating shaft. A sealing gap is formed between the pole teeth and the outer peripheral surface of the rotating shaft. Magnetic liquid is adsorbed in the sealing gap. The side of the pole shoe adjacent to the sealed container has a first gas flow chamber, which is connected to each of the first vent and the first exhaust port. A centrifugal compressor is installed in the mounting cavity. The centrifugal compressor includes an impeller with multiple blades. The impeller is connected to the rotating shaft and rotates with the rotating shaft. The impeller blows air into the first gas flow cavity through the first air outlet. The pole shoe includes a first pole shoe and a second pole shoe, and a permanent magnet is located axially between the first pole shoe and the second pole shoe and abuts against each of the first pole shoe and the second pole shoe. The first pole shoe is adjacent to the sealed container relative to the second pole shoe, and the first gas flow chamber is located on the side of the first pole shoe adjacent to the sealed container.

2. The magnetic liquid sealing device utilizing gas isolation according to claim 1, characterized in that, There are multiple impellers, which are spaced apart along the axial direction of the rotating shaft. The first air outlet is connected to the air outlet end of the downstream impeller.

3. The magnetic liquid sealing device utilizing gas isolation according to claim 1, characterized in that, The diameter of the impeller gradually increases along the direction adjacent to the sealed container, and multiple blades are spaced apart in the circumferential direction of the impeller, forming an airflow channel between two adjacent blades, the width of the airflow channel gradually increasing along the direction adjacent to the sealed container.

4. The magnetic liquid sealing device utilizing gas isolation according to claim 1, characterized in that, The centrifugal compressor includes a diffuser connected to the impeller and rotating with the impeller. The diffuser includes multiple diffuser blades located outside the blades of the impeller and spaced apart around the impeller. The flow area of ​​the flow channel between two adjacent diffuser blades gradually increases outward.

5. The magnetic liquid sealing device utilizing gas isolation according to claim 1, characterized in that, Includes a filter element, which is disposed at the vent and / or the first vent.

6. The magnetic liquid sealing device utilizing gas isolation according to claim 1, characterized in that, The magnetic liquid sealing device further includes: A first bearing is located within the cavity and supported between the housing and the rotating shaft; The second bearing is located in the cavity and supported between the housing and the shaft. The first pole shoe, the second pole shoe and the permanent magnet are located axially between the first bearing and the second bearing on the shaft, and the first bearing is adjacent to the sealed container relative to the second bearing. The first gas flow cavity is formed between the first pole shoe and the first bearing; or, The first gas flow chamber is located on the side of the first bearing adjacent to the sealed container.

7. The magnetic liquid sealing device utilizing gas isolation according to any one of claims 1-5, characterized in that, There are multiple first air outlets, which are spaced apart circumferentially on the rotating shaft; and / or, There are multiple first exhaust holes, which are spaced apart on the peripheral wall of the housing in the circumferential direction of the rotating shaft.

8. The magnetic liquid sealing device utilizing gas isolation according to any one of claims 1-5, characterized in that, The side of the pole shoe away from the sealed container has a second gas flow chamber. The housing is provided with a second exhaust port communicating with the second gas flow chamber. The rotating shaft is provided with a second vent port communicating with the mounting cavity and the second gas flow chamber. The second vent port is located upstream of the first vent port. The centrifugal compressor also blows air into the second gas flow chamber through the second vent port. The magnetic liquid sealing device includes a first filter element, which is disposed at the vent.

9. The magnetic liquid sealing device utilizing gas isolation according to claim 8, characterized in that, It includes a second filter element, which is disposed at the first air outlet and / or the second air outlet.

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