Magnetic liquid seal for cryogenic gas containment

Abstract

The application discloses a magnetic liquid sealing device for low-temperature gas sealing, which comprises a shell, a rotating assembly, a magnetic liquid sealing assembly, a mechanical sealing assembly and a clutch assembly. The shell is provided with a chamber, the rotating assembly is rotatably arranged in the chamber, the magnetic liquid sealing assembly and the mechanical sealing assembly are arranged in the chamber and sleeved on the rotating assembly, and the clutch assembly is arranged on the mechanical sealing assembly and used for controlling opening and closing of the mechanical sealing. The magnetic liquid sealing device for low-temperature gas sealing has the advantages of low-temperature resistance and low friction loss.

Description

Technical Field

[0001] This invention belongs to the field of mechanical engineering sealing technology, specifically relating to a magnetic liquid sealing device for cryogenic gas sealing. Background Technology

[0002] Magnetic liquid seals have advantages such as zero leakage, long life and low frictional viscosity, and are suitable for rotary sealing of gases at room temperature.

[0003] In sealing applications of equipment such as superconducting motors or cryogenic reactors, when the equipment is at a high speed, the frictional heat generated by the magnetic liquid seal is balanced with the external low-temperature environment, and the magnetic liquid seal can work normally. However, when the equipment is in standby or at a low speed, the leakage of cryogenic helium or nitrogen to the seal will cause the magnetic liquid to freeze and solidify, resulting in the failure of the magnetic liquid seal. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a magnetic liquid sealing device for cryogenic gas sealing that is resistant to low temperatures and has low frictional loss.

[0006] The magnetic liquid sealing device for cryogenic gas sealing according to embodiments of the present invention includes:

[0007] A housing assembly, the housing assembly including a housing having a chamber;

[0008] A rotating assembly, rotatably disposed within the chamber, the rotating assembly comprising a shaft and a thermal insulation bushing, the thermal insulation bushing being sleeved on the shaft and located on the side of the shaft axially closer to the cryogenic gas;

[0009] A magnetic liquid sealing assembly, wherein the magnetic liquid sealing assembly is located within the cavity of the housing and is sleeved on the shaft;

[0010] A mechanical seal assembly, wherein the mechanical seal is located within the cavity of the housing and is fitted onto the heat-insulating bushing;

[0011] A clutch assembly, the clutch assembly including a perforated cylindrical head screw, the clutch assembly being mounted on the mechanical seal assembly by the perforated cylindrical head screw.

[0012] The magnetic liquid sealing device for cryogenic gas sealing in this embodiment of the invention has a mechanical seal that closes when the device is stationary or operating at low speed, preventing the cryogenic gas from contacting the magnetic liquid and thus preventing the magnetic liquid seal from failing due to solidification. When operating at high speed, the mechanical seal opens, reducing heat loss. At the same time, the magnetic liquid generates heat due to viscous friction at high speed, so even if it comes into contact with the cryogenic gas, the magnetic liquid will not freeze, ensuring the reliability of the seal.

[0013] In some embodiments, the insulating bushing is made of polytetrafluoroethylene, and the inner wall of the insulating bushing has a plurality of internal teeth in the circumferential direction, which cooperate with the long groove on the shaft, and the insulating bushing rotates together with the shaft.

[0014] In some embodiments, the magnetic fluid sealing assembly includes a first pole shoe, a second pole shoe, and a permanent magnet. A radial gap is provided between the inner circumferential surfaces of the first pole shoe and the second pole shoe and the outer circumferential surface of the shaft. The radial gap is filled with magnetic fluid, and the permanent magnet is clamped between the first pole shoe and the second pole shoe.

[0015] In some embodiments, the mechanical seal assembly includes a stationary ring, a rotating ring, a spring, and a fixed seat. The fixed seat is connected to the rotating assembly via a set screw, and the rotating ring, spring, and fixed seat rotate together with the rotating assembly.

[0016] In some embodiments, the outer circumferential surfaces of the moving ring and the fixed seat are provided with the same number of internal thread blind holes, and there are multiple internal thread blind holes, which are evenly distributed in the circumferential direction of the moving ring and the fixed seat.

[0017] In some embodiments, the clutch assembly further includes a flexible rope and a steel ball. The steel ball has a through hole passing through its center. The flexible rope passes through the through hole, and both ends of the flexible rope are fixed in the through holes of the perforated cylindrical head screw. The perforated cylindrical head screw is installed on the moving ring and the fixed seat respectively through the internal thread blind hole.

[0018] In some embodiments, the flexible rope is made of a low-temperature resistant metal material;

[0019] In some embodiments, there are multiple clutch components, and the number of clutch components is the same as the number of internal thread blind holes on the outer circumferential surface of the rotating ring or the fixed seat.

[0020] In some embodiments, the magnetic liquid sealing device for cryogenic gas sealing further includes a first magnetic isolation ring and a second magnetic isolation ring;

[0021] The first magnetic shielding ring is disposed in the cavity of the housing, the outer peripheral surface of the first magnetic shielding ring is in contact with the inner peripheral surface of the cavity of the housing, and the right end face of the first magnetic shielding ring is in contact with the left end face of the first pole shoe.

[0022] The second magnetic shielding ring is disposed in the cavity of the housing. The outer peripheral surface of the second magnetic shielding ring is in contact with the inner peripheral surface of the cavity of the housing. The left end face of the second magnetic shielding ring is in contact with the right end face of the second pole shoe. The right end face of the second magnetic shielding ring is in contact with the side of the cavity of the housing.

[0023] In some embodiments, the magnetic liquid sealing device for cryogenic gas sealing further includes a first bearing, a second bearing, an inner positioning sleeve, and an outer positioning sleeve.

[0024] The outer peripheral surface of the first bearing is in contact with the inner peripheral surface of the housing cavity, the first bearing is sleeved on the shaft, and the left end face of the first bearing is in contact with the right side face of the positioning shoulder of the shaft.

[0025] The outer peripheral surface of the second bearing is in contact with the inner peripheral surface of the cavity of the housing, the second bearing is sleeved on the shaft, and the right end face of the second bearing is in contact with the left end face of the first magnetic shielding ring.

[0026] The inner positioning sleeve is sleeved on the shaft, and the inner positioning sleeve is located between the first bearing and the second bearing;

[0027] The outer peripheral surface of the outer positioning sleeve is in contact with the inner peripheral surface of the cavity of the housing, and the inner positioning sleeve is located between the first bearing and the second bearing; Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the magnetic liquid sealing device for cryogenic gas sealing in an embodiment of the present invention under static or low-speed operating conditions.

[0029] Figure 2 This is a schematic diagram of the structure of the magnetic liquid sealing device for cryogenic gas sealing under high-speed operation according to an embodiment of the present invention.

[0030] Figure 3 yes Figure 1 A schematic diagram of the cross-section at point A.

[0031] Figure 4 This is a schematic diagram of the sealing principle of a magnetic liquid sealing device for cryogenic gas sealing under static or low-speed operating conditions, according to an embodiment of the present invention.

[0032] Figure 5 This is a schematic diagram of the sealing principle of a magnetic liquid sealing device for cryogenic gas sealing under high-speed operating conditions, according to an embodiment of the present invention.

[0033] Magnetic liquid sealing device 100 for cryogenic gas sealing;

[0034] Housing assembly 1; left end cover 11; end cover screw 12; housing 13; right end cover 14;

[0035] Rotating assembly 2; Shaft 21; Thermal insulation bushing 22;

[0036] Magnetic liquid sealing assembly 3; first pole shoe 31; permanent magnet 32; second pole shoe 33;

[0037] Mechanical seal assembly 4; stationary ring 41; rotating ring 42; spring 43; fixed seat 44;

[0038] Clutch assembly 5; flexible rope 51; steel ball 52; cylindrical head screw with hole 53;

[0039] First magnetic shielding ring 101; second magnetic shielding ring 102; sealing ring 103; magnetic fluid 104; second bearing 105; outer positioning sleeve 106; inner positioning sleeve 107; first bearing 108. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below, with examples of the embodiments 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.

[0041] A magnetic liquid sealing device for cryogenic gas sealing according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0042] like Figure 1 As shown, the magnetic liquid sealing device 100 for cryogenic gas sealing according to an embodiment of the present invention includes a housing assembly 1, a rotating assembly 2, a magnetic liquid sealing assembly 3, a mechanical seal assembly 4, a clutch assembly 5, and a bearing assembly 6.

[0043] The housing assembly 1 includes a housing 13, and the housing 13 has a cavity. Specifically, as shown in the figure... Figure 1 As shown, the left end of the housing 13 has multiple threaded holes, and the left end cover 11 has corresponding through holes. The left end cover 11 is connected and fixed to the left end of the housing 13 by end cover screws 12. The middle end of the housing 13 has a flange with multiple through holes for connection and fixation with the sealed component. The right end of the housing 13 has internal threads, and the right end cover 14 has external threads. The right end cover 14 is connected and fixed to the housing 13 by threads.

[0044] The rotating assembly 2 is rotatably disposed within the cavity of the housing 13. Specifically, as shown... Figure 1 and Figure 3As shown, the inner wall of the heat-insulating bushing 22 has multiple internal teeth in the circumferential direction, and the right section of the shaft 21 has a long groove. The heat-insulating bushing 22 is fitted onto the shaft 21 through the tooth-groove fit, and the heat-insulating bushing 22 rotates together with the shaft 21. The heat-insulating bushing 22 is located on the side of the shaft 21 that is closer to the low-temperature gas in the axial direction, which is used to reduce the influence of the low-temperature gas on the shaft 21 and reduce heat conduction along the axial direction.

[0045] The magnetic liquid sealing assembly 3 is located in the cavity of the housing 13 and is sleeved on the shaft 21. Specifically, as shown... Figure 1 As shown, a radial gap exists between the inner circumferential surfaces of the first pole shoe 31 and the second pole shoe 33 and the outer circumferential surface of the shaft 21. Magnetic fluid 104 is injected into the radial gap. The permanent magnet 32 ​​is clamped between the first pole shoe 31 and the second pole shoe 33, forming a magnetic field at the radial gap, ensuring that the magnetic fluid 104 always fills the radial gap, thus achieving axial sealing of the shaft 21. The outer circumferential surfaces of the first pole shoe 31 and the second pole shoe 33 are provided with annular grooves, and the sealing ring 103 is located in the annular grooves, ensuring the sealing between the outer circumferential surfaces of the first pole shoe 31 and the second pole shoe 33 and the inner circumferential surface of the cavity of the housing 13.

[0046] The mechanical seal assembly 4 is located within the cavity of the housing 13 and is fitted onto the thermal insulation bushing 22. Specifically, as shown... Figure 1 As shown, the stationary ring 41 is fixed to the side wall of the chamber of the housing 13, and the fixed seat 44 is connected to the rotating assembly 2 by a set screw. The rotating ring 42, the spring 43, and the fixed seat 44 rotate together with the rotating assembly 2. The end faces of the stationary ring 41 and the rotating ring 42 are pressed together by the spring 43 to form an end face seal.

[0047] The clutch assembly 5 is mounted on the mechanical seal assembly 4 via a perforated cylindrical head screw 53. Specifically, as shown... Figure 1 As shown, the outer circumferential surfaces of the moving ring 42 and the fixed seat 44 are provided with internally threaded blind holes. A perforated cylindrical head screw 53 is threadedly installed on the outer circumferential surfaces of the moving ring 42 and the fixed seat 44 respectively. The steel ball 52 has a through hole passing through its center. A flexible rope 51 passes through the through hole of the steel ball 52, with the steel ball 52 located in the middle section of the flexible rope 51. One end of the flexible rope 51 is fixed to the through hole of the perforated cylindrical head screw 53 on the moving ring 42, and the other end is fixed to the through hole of the perforated cylindrical head screw 53 on the fixed seat 44.

[0048] The magnetic liquid sealing device 100 for cryogenic gas sealing according to an embodiment of the present invention, when in a static or low-speed operating condition, specifically, as... Figure 1 and Figure 4As shown, the low-temperature gas enters the cavity of the housing 13 through the radial gap between the right end cover 14 of the housing and the heat insulation bushing 22. The moving ring 42 is pressed against the stationary ring 41 under the action of the spring 43 to form an end face seal. The gap between the moving ring 42 and the heat insulation bushing 22 is sealed by the sealing ring 103, and the gap between the stationary ring 41 and the housing 13 is sealed by the sealing ring 103, thus sealing the low-temperature gas in the cavity of the right section of the housing 13 and preventing the magnetic liquid 104 from freezing and solidifying due to the low-temperature gas.

[0049] The magnetic liquid sealing device 100 for cryogenic gas sealing according to an embodiment of the present invention, specifically, under high-speed operating conditions, such as... Figure 2 and Figure 5 As shown, under the action of centrifugal force, the steel ball 52 stretches the flexible rope 51 outward. Through the perforated cylindrical head screw 53, the moving ring 42 causes the spring 43 to contract under the action of tension, and the moving ring 42 separates from the stationary ring 41, forming an end face gap. The low temperature gas first passes through the end face gap between the moving ring 42 and the stationary ring 41, and then through the radial gap between the stationary ring 41 and the heat insulation bushing 22, reaching the magnetic liquid sealing assembly 3. Under high speed conditions, the magnetic liquid 104 heats up due to viscous friction. Even if it comes into contact with the low temperature gas, the magnetic liquid will not freeze and solidify, ensuring the reliability of the seal. Moreover, because of the separation of the moving ring 42 and the stationary ring 41, the frictional loss of the mechanical seal assembly 4 is reduced, and the impact on the low temperature gas is reduced.

[0050] In some embodiments, the material of the heat-insulating bushing 22 is polytetrafluoroethylene.

[0051] In some embodiments, the flexible rope 51 is made of a low-temperature resistant metal material.

[0052] In some embodiments, there are multiple internal thread blind holes on the outer peripheral surfaces of the rotating ring 42 and the fixed seat 44. The number of internal thread blind holes on the outer peripheral surface of the rotating ring 42 is the same as the number of internal thread blind holes on the outer peripheral surface of the fixed seat 44. The multiple internal thread blind holes are evenly distributed along the circumference of the rotating ring 42 and the fixed seat 44.

[0053] In some embodiments, there are multiple clutch components 5, and the number of clutch components 5 is the same as the number of internal thread blind holes on the outer peripheral surface of the moving ring 42 or the fixed seat 44.

[0054] In some embodiments, the magnetic liquid sealing device 100 for cryogenic gas sealing further includes a first magnetic isolation ring 101 and a second magnetic isolation ring 102. Specifically, as Figure 1As shown, the first magnetic shielding ring 101 is disposed in the cavity of the housing 13. The outer peripheral surface of the first magnetic shielding ring 101 is in contact with the inner peripheral surface of the cavity of the housing 13, and the right end face of the first magnetic shielding ring 101 is in contact with the left end face of the first pole shoe 31. The second magnetic shielding ring 102 is disposed in the cavity of the housing 13. The outer peripheral surface of the second magnetic shielding ring 102 is in contact with the inner peripheral surface of the cavity of the housing 13, the left end face of the second magnetic shielding ring 102 is in contact with the right end face of the second pole shoe 33, and the right end face of the second magnetic shielding ring 102 is in contact with the side of the cavity of the housing 13. The first magnetic shielding ring 102 and the second magnetic shielding ring 103 can prevent magnetic leakage from the side of the permanent magnet 32 ​​and ensure the sealing performance of the magnetic liquid sealing assembly 3.

[0055] In some embodiments, the magnetic liquid sealing device 100 for cryogenic gas sealing further includes a first bearing 108, a second bearing 105, an inner positioning sleeve 107, and an outer positioning sleeve 106. Specifically, as Figure 1 As shown, the outer peripheral surface of the first bearing 108 is in contact with the inner peripheral surface of the cavity of the housing 13. The first bearing 108 is sleeved on the shaft 21, and its left end face is in contact with the right side of the positioning shoulder of the shaft 21, thus positioning the rotating assembly 2. The outer peripheral surface of the second bearing 105 is in contact with the inner peripheral surface of the cavity of the housing 13. The second bearing 105 is sleeved on the shaft 21, and its right end face is in contact with the left end face of the first magnetic shielding ring 101. The inner positioning sleeve 107 is sleeved on the shaft 21 and is located between the first bearing 108 and the second bearing 105. The outer peripheral surface of the outer positioning sleeve 106 is in contact with the inner peripheral surface of the cavity of the housing 13 and is located between the first bearing 108 and the second bearing 105, thereby enabling the rotating assembly 2 to rotate stably.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 seal device for cryogenic gas containment, characterized by, include: A housing assembly, the housing assembly including a housing having a chamber; A rotating assembly is rotatably disposed in the chamber. The rotating assembly includes a shaft and a heat-insulating bushing. The heat-insulating bushing is made of polytetrafluoroethylene and is sleeved on the shaft. The inner wall of the heat-insulating bushing has multiple internal teeth in the circumferential direction, which cooperate with the long grooves on the shaft. The heat-insulating bushing rotates with the shaft and is located on the side of the shaft that is closer to the low-temperature gas in the axial direction. A magnetic liquid sealing assembly includes a first pole shoe, a second pole shoe, and a permanent magnet. A radial gap is left between the inner circumferential surfaces of the first pole shoe and the second pole shoe and the outer circumferential surface of the shaft. The radial gap is filled with magnetic liquid. The permanent magnet is clamped between the first pole shoe and the second pole shoe. The magnetic liquid sealing assembly is located in the cavity of the housing and is sleeved on the shaft. A mechanical seal assembly, comprising a stationary ring, a rotating ring, a spring, and a fixed seat, is located within the cavity of the housing and is fitted onto the heat-insulating bushing. The fixed seat is connected to the rotating assembly via a set screw. The rotating ring, spring, and fixed seat rotate together with the rotating assembly. The rotating ring and fixed seat are machined with internally threaded blind holes. The clutch assembly includes a perforated cylindrical head screw, a flexible rope, and a steel ball. The steel ball has a through hole passing through its center. The flexible rope passes through the through hole, and its two ends are fixed in the through hole of the perforated cylindrical head screw. The perforated cylindrical head screw is installed on the moving ring and the fixed seat of the mechanical seal assembly through the internal thread blind hole, respectively.

2. The magnetic liquid sealing device for cryogenic gas sealing according to claim 1, characterized in that, When the magnetic liquid sealing device is stationary or operating at low speed, the moving ring of the mechanical seal assembly is pressed against the stationary ring by the spring, forming an end face seal and sealing the cryogenic gas in the chamber of the right section of the housing. When the magnetic liquid sealing device is operating at high speed, the steel ball stretches the flexible rope outward under the action of centrifugal force. Through the perforated cylindrical head screw, the moving ring causes the spring to contract under the action of tension, and the moving ring separates from the stationary ring, forming an end face gap. The cryogenic gas passes through the end face gap and then through the radial gap between the stationary ring and the heat insulation bushing to reach the magnetic liquid sealing assembly.

3. The magnetic liquid sealing device for cryogenic gas sealing according to claim 1, characterized in that, The flexible rope is made of a low-temperature resistant metal material.

4. The magnetic liquid sealing device for cryogenic gas sealing according to claim 1, characterized in that, There are multiple clutch assemblies, and the number of clutch assemblies is the same as the number of internal thread blind holes on the outer circumferential surface of the moving ring or the fixed seat.

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