Two-stage seal device

Abstract

The application discloses a two-stage sealing device, which comprises an inner joint, an outer joint, a first sealing assembly and a second sealing assembly, the axis direction of the inner joint is arranged along a first direction, the outer joint is sleeved on the inner joint, and the first end of the inner joint is located in the outer joint, the inner joint and the outer joint are at least partially spaced apart in a second direction to form a gap, the second direction is orthogonal to the first direction, the first sealing assembly and the second sealing assembly are both located in the gap, the second sealing assembly comprises an inner pole shoe, an outer pole shoe and a permanent magnet, the inner pole shoe, the outer pole shoe and the permanent magnet are all sleeved on the inner joint, the permanent magnet is located between the inner pole shoe and the outer pole shoe, and the inner pole shoe and the outer pole shoe are both provided with magnetic fluid, which is blocked between the inner joint and the outer joint under the magnetic force of the permanent magnet. The two-stage sealing device of the application seals the pipeline through two-stage sealing and adopts magnetic fluid, thereby improving the sealing effect of the pipeline and reducing the leakage amount of gas in the pipeline.

Description

Technical Field

[0001] This invention belongs to the field of gas sealing technology, and particularly relates to a two-stage sealing device. Background Technology

[0002] High-pressure gases are widely used in industrial production. Gas sealing is more difficult than liquid sealing because gas molecules are small and can pass through macroscopically well-contact sealing gaps and macroscopically dense sealing materials, causing leakage. Moreover, the leakage of high-pressure gases increases with increasing pressure, and the leakage of flammable, explosive, and toxic gases can cause serious hazards.

[0003] The various joints in high-pressure gas pipelines are the main sources of gas leakage. Related technologies for sealing high-pressure gases mainly include the following sealing structures: 1. Hard seals: Hard seals use dense materials such as soft metals, stainless steel, and graphite, or other metallic or non-metallic materials as sealing elements. The sealing element is machined into a specific shape, and the sealing surface undergoes precision machining, grinding, polishing, and coating to improve the surface contact. The sealing structure is designed to maintain a sufficiently large normal load, ensuring a tight seal and meeting the requirements for pressure resistance and leakage rate. 2. Soft seals: Soft seals use materials with low rigidity, such as rubber and plastic, as sealing elements, placed between two sealing interfaces. By applying a normal load, the sealing element deforms at the contact interface, blocking the leakage path and achieving a tight seal with the sealed component. 3. Multi-stage seals: Multi-stage seals consist of multiple sealing structures connected in series. The high-pressure stage is a hard or soft seal, while the low-pressure stage is usually a soft seal, to achieve a lower gas leakage rate.

[0004] However, among the above-mentioned sealing structures, hard seals have high requirements for the smoothness of the sealing interface, high application costs, are easily damaged, have poor reusability, have a large load on the sealing structure, are complex in structure, and have low reliability. Hard seals also have a high leakage rate when used for gases. Soft seals have limited sealing capacity because the gas medium cannot be avoided by penetrating through the soft sealing material itself, and the pressure resistance of soft seals is limited, resulting in poor reliability in high-pressure media. As the service time increases, gas will accumulate between the multiple sealing structures, and the amount of gas leakage will also increase with the increase of gas pressure. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a two-stage sealing device that improves the sealing effect of the pipeline and reduces gas leakage through two-stage sealing and the use of magnetic fluid.

[0006] The two-stage sealing device of this invention includes an inner connector, an outer connector, a first sealing component, and a second sealing component. The axial direction of the inner connector is arranged along a first direction. The outer connector is sleeved on the inner connector, and the first end of the inner connector is located inside the outer connector. The inner connector and the outer connector are at least partially spaced apart in a second direction to form a gap. The second direction is orthogonal to the first direction. The first sealing component is located within the gap, and the second sealing component is located within the gap. The first sealing component and the second sealing component are arranged sequentially from the first end of the inner connector to the second end of the inner connector. The second sealing component includes an inner pole shoe, an outer pole shoe, and a permanent magnet. The inner pole shoe, the outer pole shoe, and the permanent magnet are all sleeved on the inner connector. The permanent magnet is located between the inner pole shoe and the outer pole shoe. Magnetorheological fluid is provided on the inner and outer peripheral walls of the inner pole shoe and the inner and outer peripheral walls of the outer pole shoe. The magnetorheological fluid is sealed between the inner connector and the outer connector under the magnetic force of the permanent magnet.

[0007] The two-stage sealing device of this invention improves the sealing effect of the pipeline and reduces the amount of gas leakage in the pipeline by using two-stage sealing and magnetic fluid to seal the pipeline.

[0008] In some embodiments, the second sealing assembly is movable relative to the inner connector in the first direction to give the second sealing assembly a sealing position and an venting position. In the sealing position, the magnetofluid is sealed between the inner connector and the outer connector under the magnetic force of the permanent magnet. In the venting position, the magnetofluid is separated from the outer peripheral wall of the inner connector and / or the inner peripheral wall of the outer connector.

[0009] In some embodiments, the two-stage sealing device further includes a pusher connected to the inner connector and movable along the first direction, the pusher abutting against a first end of the second sealing assembly, the pusher being used to push the second sealing assembly to move along the first direction so that the second sealing assembly switches between the sealing position and the venting position.

[0010] In some embodiments, the two-stage sealing device further includes an elastic element located within the gap, abutting a first end of the elastic element against the outer connector and / or the inner connector, and abutting a second end of the elastic element against a second end of the second sealing assembly. The elastic element and the pusher respectively apply opposite thrusts to the second sealing assembly to cause the second sealing assembly to reciprocate between the sealing position and the venting position.

[0011] In some embodiments, the outer connector has a first step, a second step, and a third step, the first step, the second step, and the third step being arranged sequentially from a first end of the inner connector to a second end of the inner connector, the second step being away from the axis of the inner connector relative to the first step, the third step being away from the axis of the inner connector relative to the second step, the gap including a first gap and a second gap, the second step being at least partially spaced from the inner connector in the second direction, the first step, the second step, and the inner connector defining the first gap, the third step being at least partially spaced from the inner connector in the second direction, the second step, the third step, and the inner connector defining the second gap, the first sealing assembly being located within the first gap, and the second sealing assembly being located within the second gap.

[0012] In some embodiments, the inner connector and / or the outer connector are provided with a first inclined surface located within the second gap, the first inclined surface causing the width of the second gap to gradually decrease in the direction from the first end of the inner connector to the second end of the inner connector, or the first inclined surface causing the width of the second gap to gradually increase in the direction from the first end of the inner connector to the second end of the inner connector.

[0013] In some embodiments, both the inner pole shoe and the outer pole shoe have a plurality of pole teeth spaced apart along a first direction, and the magnetofluid is disposed on the pole teeth.

[0014] In some embodiments, the second sealing assembly further includes a first magnetic isolation ring, a second magnetic isolation ring, and a third magnetic isolation ring. The first magnetic isolation ring and the second magnetic isolation ring are both sleeved on the inner connector. The first magnetic isolation ring, the inner pole shoe, the permanent magnet, the outer pole shoe, and the second magnetic isolation ring are arranged sequentially along the first direction. The third magnetic isolation ring is sleeved on the permanent magnet, and the third magnetic isolation ring abuts against the inner pole shoe and the outer pole shoe, respectively.

[0015] In some embodiments, the first sealing assembly includes a sealing ring fitted onto the inner connector, the inner diameter of the sealing ring being smaller than the outer diameter of the inner connector, and the wire diameter of the sealing ring being larger than the width of the gap.

[0016] In some embodiments, the first sealing assembly further includes a retaining ring, which is sleeved on the inner connector. The sealing ring and the retaining ring are arranged sequentially from the first end of the inner connector to the second end of the inner connector, and the retaining ring abuts against the sealing ring and the inner connector, respectively. Attached Figure Description

[0017] Figure 1This is a schematic diagram of a two-stage sealing device according to an embodiment of the present invention.

[0018] Figure 2 This is a partial structural diagram of the second gap in an embodiment of the present invention.

[0019] Figure label:

[0020] Internal connector 1; First inclined surface 11; First shoulder 12; Second shoulder 13;

[0021] External connector 2; First step 21; Second step 22; Third step 23;

[0022] Gap 3; First gap 31; Second gap 32;

[0023] First sealing component 4; sealing ring 41; retaining ring 42;

[0024] Second sealing assembly 5; inner pole shoe 51; outer pole shoe 52; permanent magnet 53; magnetofluid 54; pole teeth 55; first magnetic isolation ring 56; second magnetic isolation ring 57; third magnetic isolation ring 58;

[0025] Push component 6;

[0026] 7. Elastic component. Detailed Implementation

[0027] 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.

[0028] The following describes a two-stage sealing device according to an embodiment of the present invention with reference to the accompanying drawings.

[0029] For example Figure 1 and Figure 2 As shown, the two-stage sealing device of this invention includes an inner connector 1, an outer connector 2, a first sealing component 4, and a second sealing component 5.

[0030] Among them, the axial direction of the inner connector 1 is along the first direction (e.g., Figure 1 The outer connector 2 is sleeved on the inner connector 1, and the first end of the inner connector 1 (as shown in the left and right directions) is configured such that the outer connector 2 is sleeved on the inner connector 1 ... Figure 1 The left end shown is located inside the outer connector 2, and the inner connector 1 and the outer connector 2 are in the second direction (as shown). Figure 1 The inner connector 1 shown is at least partially spaced in the radial direction to form a gap 3, and the second direction is orthogonal to the first direction.

[0031] Specifically, the outer wall surface of the left end of the inner connector 1 is provided with an external thread (not shown), and the inner wall surface of the outer connector 2 is provided with an internal thread (not shown) that matches the external thread, so that the inner connector 1 and the outer connector 2 are connected by threads. The internal and external threads facilitate the assembly of the inner connector 1 and the outer connector 2 into the corresponding positions, and provide axial force to the inner connector 1 and the outer connector 2 to prevent the inner connector 1 and the outer connector 2 from separating. The outer wall surface of the middle part of the inner connector 1 is separated from the inner wall surface of the outer connector 2 and is spaced apart, so that the inner connector 1 and the outer connector 2 are separated in the radial direction of the inner connector 1 to form a gap 3 for installing the sealing assembly.

[0032] The first sealing component 4 is located within the gap 3 and is in direct contact with the high-pressure gas in the pipeline. Due to the large pressure difference on both sides of the first sealing component 4, the first sealing component 4 can be in the form of a soft seal or a hard seal. When the pressure in the pipeline increases, the side of the first sealing component 4 is subjected to axial pressure. Due to the obstruction of the inner connector 1 and the outer connector 2, the first sealing component 4 is subjected to axial compression. When the first sealing component 4 is subjected to axial compression, it will generate radial contact pressure with the inner connector 1 and the outer connector 2. The magnitude of the radial contact pressure increases with the increase of gas pressure, thereby achieving a high-pressure level seal.

[0033] The second sealing assembly 5 is located within the gap 3, and the first sealing assembly 4 and the second sealing assembly 5 are located at the first end of the inner connector 1 towards the second end of the inner connector 1 (e.g., Figure 1 Arranged sequentially from left to right (as shown), the first sealing assembly 4 and the second sealing assembly 5 both seal the gap 3 to provide a two-stage seal for the inner connector 1 and the outer connector 2. The second sealing assembly 5 includes an inner pole shoe 51, an outer pole shoe 52, and a permanent magnet 53. The inner pole shoe 51, outer pole shoe 52, and permanent magnet 53 are all fitted onto the inner connector 1. The permanent magnet 53 is located between the inner pole shoe 51 and the outer pole shoe 52. Magnetic fluid 54 is provided on the inner and outer peripheral walls of the inner pole shoe 51 and the outer pole shoe 52. The magnetic fluid 54, under the magnetic force of the permanent magnet 53, seals the space between the inner connector 1 and the outer connector 2. Because the first sealing assembly 4 seals the inner connector 1 and the outer connector 2, the gas pressure between the first sealing assembly 4 and the second sealing assembly 5 is within the pressure resistance range of the magnetic fluid 54 seal. The magnetic fluid 54 seal has excellent performance, and the gas leakage rate can be as low as 10%. -12 Pa·m 3 / s.

[0034] It should be noted that, as Figure 2As shown, the inner pole shoe 51, outer pole shoe 52, permanent magnet 53, magnetofluid 54, outer connector 2, and inner connector 1 form two magnetic circuits. The loop is: permanent magnet 53 → inner pole shoe 51 → magnetofluid 54 → outer connector 2 → outer pole shoe 52 → magnetofluid 54 → permanent magnet 53. The magnetofluid 54 located on the outer peripheral wall of the inner pole shoe 51 blocks the space between the outer peripheral wall of the inner pole shoe 51 and the inner peripheral wall of the outer connector 2. Similarly, the magnetofluid 54 located on the outer peripheral wall of the outer pole shoe 52 blocks the space between the outer peripheral wall of the outer pole shoe 52 and the inner peripheral wall of the outer connector 2. The loop continues with the connection between permanent magnet 53 and inner pole shoe 51. The magnetic fluid 54 → inner connector 1 → outer pole shoe 52 → magnetic fluid 54 → permanent magnet 53 form another magnetic circuit, so that the magnetic fluid 54 located on the inner peripheral wall of the inner pole shoe 51 is sealed between the inner peripheral wall of the inner pole shoe 51 and the outer peripheral wall of the inner connector 1, and the magnetic fluid 54 located on the inner peripheral wall of the outer pole shoe 52 is sealed between the inner peripheral wall of the outer pole shoe 52 and the outer peripheral wall of the inner connector 1. Thus, the magnetic fluid 54 located between the pole shoes (inner pole shoe 51 and outer pole shoe 52) and the pipe joints (inner connector 1 and outer connector 2) forms a seal for the inner connector 1 and the outer connector 2 under the action of the magnetic field of the permanent magnet 53.

[0035] The two-stage sealing device of this invention employs two-stage sealing. The first sealing component 4 provides high-pressure sealing for the inner connector 1 and the outer connector 2. The magnetic fluid 54 on the inner pole shoe 51 seals the gap 3 to seal the inner connector 1 and the outer connector 2, and the magnetic fluid 54 on the outer pole shoe 52 also seals the gap 3 to seal the inner connector 1 and the outer connector 2. This allows the second sealing component 5 to form a two-stage magnetic fluid 54 seal, effectively improving the sealing effect of the pipeline and reducing the leakage rate of high-pressure gas at the sealing joint.

[0036] like Figure 1 and Figure 2 As shown, in some embodiments, the second sealing assembly 5 is positioned relative to the inner connector 1 in a first direction (e.g., Figure 1 The second sealing assembly 5 can be moved in the left-right direction (as shown) to have a sealing position and an exhaust position. In the sealing position, the magnetic fluid 54 is sealed between the inner connector 1 and the outer connector 2 under the magnetic force of the permanent magnet 53 to seal the pipeline. In the exhaust position, the magnetic fluid 54 is separated from the outer peripheral wall of the inner connector 1 and / or the inner peripheral wall of the outer connector 2, so that the gas between the first sealing assembly 4 and the second sealing assembly 5 can be selectively discharged and captured. On the one hand, this reduces the harm of gas to the environment and construction personnel, and on the other hand, it reduces the gas pressure between the first sealing element and the second sealing element, which helps to reduce the gas leakage flow and improve the safety and reliability of the sealing structure.

[0037] like Figure 1 As shown, in some embodiments, the two-stage sealing device further includes a pusher 6, which is connected to the inner connector 1 and movable along a first direction. The pusher 6 is connected to the first end of the second sealing assembly 5 (e.g., Figure 1(shown on the right end) abuts against each other, and the pusher 6 is used to push the second sealing assembly 5 to move along the first direction so that the second sealing assembly 5 switches between the sealing position and the venting position.

[0038] Optionally, the pusher 6 can be one or more of a nut, push rod, slider, etc. By moving the pusher 6, the pusher 6 drives the second sealing assembly 5 to move along the first direction, thereby switching the second sealing assembly 5 between the sealing position and the venting position.

[0039] For example Figure 1 As shown, in a specific embodiment, the pusher 6 is a nut, which is sleeved on the inner connector 1 and threadedly connected to the inner connector 1. The left end of the nut is located inside the gap 3 and abuts against the right end of the second sealing component 5. The right end of the nut is located outside the gap 3. Rotating the nut causes it to move to the left relative to the inner connector 1 along the axial direction of the inner connector 1 under the action of the thread. The nut pushes the second sealing component 5 to move to the left relative to the inner connector 1, thereby switching the second sealing component 5 between the sealing position and the venting position.

[0040] like Figure 1 As shown, the two-stage sealing device further includes an elastic element 7, which is located within the gap 3. The first end of the elastic element 7 (e.g., Figure 1 The left end shown abuts against the outer connector 2 and / or the inner connector 1, and the second end of the elastic element 7 (as shown) Figure 1 The right end shown) and the second end of the second sealing assembly 5 (as shown) Figure 1 The left end (as shown) abuts against each other, and the elastic member 7 and the pusher 6 respectively apply opposite thrusts to the second sealing assembly 5 so that the second sealing assembly 5 reciprocates between the sealing position and the venting position.

[0041] Optionally, the elastic element 7 is one or more of the following: metal spring, spring sheet, air spring, rubber spring, etc.

[0042] Specifically, the left end of the elastic element 7 abuts against the outer connector 2, and the right end of the elastic element 7 abuts against the left end of the second sealing assembly 5. Under the action of its own elastic force, the elastic element 7 applies a rightward thrust to the second sealing assembly 5, causing the second sealing assembly 5 to abut against the right end of the inner connector 1 under the action of the elastic element 7. At this time, the second sealing assembly 5 is in the sealing position. The pushing element 6 pushes the second sealing assembly 5 to the left until the second sealing assembly 5 moves to the venting position, completing the switch of the second sealing assembly 5 from the sealing position to the venting position. At this time, the second sealing assembly 5 compresses the elastic element 7 to the left, increasing the deformation of the elastic element 7. When the pushing element 6 separates from the second sealing assembly or moves to the right until the second elastic assembly moves to the venting position, the elastic element 7 pushes the second sealing assembly 5 to the right under the action of its own elastic force until the second sealing assembly 5 abuts against the right end of the inner connector 1, causing the second sealing assembly 5 to move to the sealing position, completing the reset of the second sealing assembly 5.

[0043] like Figure 1 As shown, in some embodiments, the outer connector 2 has a first step 21, a second step 22, and a third step 23, the first step 21, the second step 22, and the third step 23 being in the direction from the first end of the inner connector 1 to the second end of the inner connector 1 (e.g., Figure 1 Arranged sequentially from left to right (as shown), the second step 22 is farther from the axis of the inner joint 1 relative to the first step 21, and the third step 23 is farther from the axis of the inner joint 1 relative to the second step 22. In other words, the inner diameter of the second step 22 is larger than the inner diameter of the first step 21, and the inner diameter of the third step 23 is larger than the inner diameter of the second step 22.

[0044] The gap 3 includes a first gap 31 and a second gap 32. The second step 22 is at least partially spaced from the inner connector 1 in the second direction. The first step 21, the second step 22 and the inner connector 1 define the first gap 31. The third step 23 is at least partially spaced from the inner connector 1 in the second direction. The second step 22, the third step 23 and the inner connector 1 define the second gap 32, so that the first gap 31 and the second gap 32 are spaced apart not only in the first direction but also in the second direction. The first sealing component 4 is located in the first gap 31 and the second sealing component 5 is located in the second gap 32, so that the first sealing component 4 and the second sealing component 5 are separated, further improving the sealing performance of the sealing structure.

[0045] For example Figure 1 As shown, the inner connector 1 further has a first shoulder 12 and a second shoulder 13. The first shoulder 12 is located in the first gap 31, and the second shoulder 13 is located in the second gap 32. The right end of the first sealing component 4 abuts against the first shoulder 12. The first shoulder 12 blocks the first sealing component 4 to prevent the first sealing component 4 from disengaging from the first gap 31. When the second sealing component 5 is in the sealing position, the right end of the second sealing component 5 abuts against the second shoulder 13. The second shoulder 13 plays a limiting role for the second seal.

[0046] like Figure 1 and Figure 2 As shown, in some embodiments, the inner connector 1 and / or the outer connector 2 are provided with a first inclined surface 11 located within the second gap 32, the first inclined surface 11 causing the width of the second gap 32 to gradually decrease in the direction from the first end of the inner connector 1 to the second end of the inner connector 1.

[0047] It should be noted that when the second sealing assembly 5 moves to the left under the action of the pusher 6, the distance between the inner pole shoe 51 and the first inclined surface 11 gradually increases, causing the sealing performance of the magnetic fluid 54 on the inner pole shoe 51 to the second gap 32 to decrease. At the same time, the distance between the outer pole shoe 52 and the first inclined surface 11 gradually increases, causing the sealing performance of the magnetic fluid 54 on the outer pole shoe 52 to the second gap 32 to decrease. The gas accumulated on the left side of the second sealing assembly 5 escapes from between the magnetic fluid 54 and the first inclined surface 11 to discharge the gas accumulated on the left side of the second sealing assembly 5 from the second gap 32. When the pusher 6 moves to the right, the second sealing assembly 5 moves to the right under the action of the elastic force of the elastic member 7, and the distance between the magnetic fluid 54 and the first inclined surface 11 gradually decreases, thereby enhancing the sealing performance of the magnetic fluid 54 to the second gap 32.

[0048] Furthermore, the inner pole shoe 51 and / or the outer pole shoe 52 are provided with a second inclined surface that matches the first inclined surface 11.

[0049] like Figure 1 and Figure 2 As shown, in a specific embodiment, the inner connector 1 is provided with a first inclined surface 11 located within the second gap 32. The first inclined surface 11 gradually moves away from the axis of the inner connector 1 in the direction from left to right, that is, the first inclined surface 11 gradually moves closer to the inner wall surface of the outer connector 2 in the direction from left to right, so that the width of the second gap 32 gradually decreases in the direction from left to right. The inner peripheral wall of the inner pole shoe 51 and the inner peripheral wall of the outer pole shoe 52 are both provided with a second inclined surface that matches the first inclined surface 11. The second inclined surface and the first inclined surface 11 have the same inclination direction and inclination angle, so that when the second sealing assembly 5 is in the sealing position, the magnetic fluid 54 on the inner peripheral wall of the inner pole shoe 51 and the magnetic fluid 54 on the inner peripheral wall of the outer pole shoe 52 fit more closely with the first inclined surface 11 to improve the sealing performance of the magnetic fluid 54 on the second gap 32.

[0050] In other embodiments (not shown), the inner connector 1 and / or the outer connector 2 are provided with a first inclined surface 11 located within the second gap 32, the first inclined surface 11 causing the width of the second gap 32 to gradually increase in the direction from the first end of the inner connector 1 to the second end of the inner connector 1.

[0051] It should be noted that when the second sealing assembly 5 moves to the right under the elastic force of the elastic member 7, the distance between the inner pole shoe 51 and the first inclined surface 11 gradually increases, causing the sealing performance of the magnetic fluid 54 on the inner pole shoe 51 to the second gap 32 to decrease. At the same time, the distance between the outer pole shoe 52 and the first inclined surface 11 gradually increases, causing the sealing performance of the magnetic fluid 54 on the outer pole shoe 52 to the second gap 32 to decrease. The gas accumulated on the left side of the second sealing assembly 5 escapes from between the magnetic fluid 54 and the first inclined surface 11 to discharge the gas accumulated on the left side of the second sealing assembly 5 from the second gap 32. When the pushing member 6 moves to the left and pushes the second sealing assembly 5 to the left, the distance between the magnetic fluid 54 and the first inclined surface 11 gradually decreases, thereby enhancing the sealing performance of the magnetic fluid 54 to the second gap 32.

[0052] In a specific embodiment (not shown), the inner connector 1 is provided with a first inclined surface 11 located within the second gap 32. The first inclined surface 11 gradually approaches the axis of the inner connector 1 from left to right, that is, the first inclined surface 11 gradually moves away from the inner wall surface of the outer connector 2 from left to right, so that the width of the second gap 32 gradually increases from left to right. The inner peripheral wall of the inner pole shoe 51 and the inner peripheral wall of the outer pole shoe 52 are both provided with a second inclined surface that matches the first inclined surface 11. The second inclined surface and the first inclined surface 11 have the same inclination direction and inclination angle, so that when the second sealing assembly 5 is in the sealing position, the magnetic fluid 54 on the inner peripheral wall of the inner pole shoe 51 and the magnetic fluid 54 on the inner peripheral wall of the outer pole shoe 52 fits more closely with the first inclined surface 11 to improve the sealing performance of the magnetic fluid 54 on the second gap 32.

[0053] like Figure 1 and Figure 2 As shown, in some embodiments, both the inner pole shoe 51 and the outer pole shoe 52 have a plurality of pole teeth 55 spaced apart along a first direction to obtain a better magnetic line linear distribution, and the magnetic fluid 54 is disposed on the pole teeth 55.

[0054] like Figure 1 and Figure 2 As shown, in a specific embodiment, the inner pole shoe 51 has three first pole teeth and three second pole teeth. The three first pole teeth are all located on the outer peripheral wall of the inner pole shoe 51 and are distributed at intervals in the left and right direction. The end of the first pole tooth near the outer connector 2 is a plane. The three second pole teeth are all located on the inner peripheral wall of the inner pole shoe 51 and are distributed at intervals in the left and right direction. The end of the second pole tooth near the first inclined surface 11 is provided with a third inclined surface that matches the first inclined surface 11.

[0055] like Figure 1 and Figure 2As shown, in a specific embodiment, the outer pole shoe 52 has three third pole teeth and three fourth pole teeth. The three third pole teeth are all located on the outer peripheral wall of the outer pole shoe 52 and are distributed at intervals in the left and right direction. The end of the third pole tooth near the outer connector 2 is a plane. The three fourth pole teeth are all located on the inner peripheral wall of the outer pole shoe 52 and are distributed at intervals in the left and right direction. The end of the fourth pole tooth near the first inclined surface 11 is provided with a fourth inclined surface that matches the first inclined surface 11.

[0056] For example Figure 1 and Figure 2 As shown, in some embodiments, the second sealing assembly 5 further includes a first magnetic shielding ring 56, a second magnetic shielding ring 57, and a third magnetic shielding ring 58. The first magnetic shielding ring 56 and the second magnetic shielding ring 57 are both sleeved on the inner connector 1. The first magnetic shielding ring 56, the inner pole shoe 51, the permanent magnet 53, the outer pole shoe 52, and the second magnetic shielding ring 57 are aligned along a first direction (e.g., ...). Figure 1 Arranged sequentially in the left-right direction (as shown), the third magnetic isolation ring 58 is sleeved on the permanent magnet 53, and the third magnetic isolation ring 58 abuts against the inner pole shoe 51 and the outer pole shoe 52 respectively. The first magnetic isolation ring 56, the second magnetic isolation ring 57 and the third magnetic isolation ring 58 separate the magnetic circuit from the elastic member 7 and the pushing member 6.

[0057] like Figure 1 As shown, in some embodiments, the first sealing assembly 4 includes a sealing ring 41, which is fitted onto the inner connector 1. The inner diameter of the sealing ring 41 is smaller than the outer diameter of the inner connector 1, and the wire diameter of the sealing ring 41 is larger than the width of the gap 3. In other words, the wire diameter of the sealing ring 41 is greater than the difference between the inner diameter of the outer connector 2 and the outer diameter of the inner connector 1 at the gap 3.

[0058] It should be noted that the sealing ring 41 is in a radially compressed state in the initial assembly state, providing initial sealing force. When the pressure in the pipeline increases, the sealing ring 41 is subjected to axial extrusion force, which presses the sealing ring 41 into the gap 3. The axial extrusion force causes radial contact pressure to be generated between the sealing ring 41 and the inner connector 1 and the outer connector 2. The contact pressure increases with the increase of the gas pressure in the pipeline, thus achieving high-pressure sealing.

[0059] Optionally, the sealing ring 41 is a rubber sealing ring 41. The rubber sealing ring 41 has a large bulk modulus, which causes the rubber sealing ring 41 to deform under axial pressure, thereby increasing the radial contact pressure between the sealing ring 41 and the inner connector 1 and the outer connector 2. The sealing ring 41 can be O-shaped, V-shaped, etc.

[0060] like Figure 1 As shown, in some embodiments, the first sealing assembly 4 further includes a retaining ring 42, which is sleeved on the inner connector 1. The sealing ring 41 and the retaining ring 42 are arranged sequentially from the first end of the inner connector 1 to the second end of the inner connector 1, and the retaining ring 42 abuts against the sealing ring 41 and the inner connector 1 respectively.

[0061] It is understandable that when the gas pressure inside the pipeline is high, the sealing ring 41 may be squeezed out of the gap 3. A retaining ring 42 is arranged on the low-pressure side of the sealing ring 41 to improve the pressure resistance of the sealing structure.

[0062] 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 do not 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A two-stage seal apparatus, characterized by, include: An inner connector, wherein the axial direction of the inner connector is arranged along a first direction; An outer connector is sleeved on an inner connector, with the first end of the inner connector located inside the outer connector. The inner connector and the outer connector are at least partially spaced apart in a second direction to form a gap. The second direction is orthogonal to the first direction. The outer connector has a first step, a second step, and a third step, which are sequentially arranged from the first end of the inner connector to the second end of the inner connector. The second step is away from the axis of the inner connector relative to the first step, and the third step is away from the axis of the inner connector relative to the second step. The gap includes a first gap and a second gap. The second step is at least partially spaced apart from the inner connector in the second direction. The first step, the second step, and the inner connector define the first gap. The third step is at least partially spaced apart from the inner connector in the second direction. The second step, the third step, and the inner connector define the second gap. A first sealing assembly is located within the first gap; The second sealing assembly is located within the second gap, and the first sealing assembly and the second sealing assembly are arranged sequentially from the first end of the inner connector to the second end of the inner connector. The second sealing assembly includes an inner pole shoe, an outer pole shoe, and a permanent magnet. The inner pole shoe, the outer pole shoe, and the permanent magnet are all sleeved on the inner connector. The permanent magnet is located between the inner pole shoe and the outer pole shoe. Magnetorheological fluid is provided on the inner and outer peripheral walls of the inner pole shoe and the inner and outer peripheral walls of the outer pole shoe. The magnetorheological fluid is sealed between the inner connector and the outer connector under the magnetic force of the permanent magnet. The inner connector and / or the outer connector are provided with a first inclined surface located within the second gap. The first inclined surface causes the width of the second gap to gradually decrease in the direction from the first end of the inner connector to the second end of the inner connector, or the first inclined surface causes the width of the second gap to gradually increase in the direction from the first end of the inner connector to the second end of the inner connector. A pusher is connected to the inner connector and movable along the first direction. The pusher abuts against the first end of the second sealing assembly. The pusher is used to push the second sealing assembly to move along the first direction so that the second sealing assembly switches between a sealing position and a venting position. The second sealing assembly is movable relative to the inner connector in the first direction to have a sealing position and an exhaust position. In the sealing position, the magnetofluid is sealed between the inner connector and the outer connector under the magnetic force of the permanent magnet. In the exhaust position, the magnetofluid is separated from the outer peripheral wall of the inner connector and / or the inner peripheral wall of the outer connector, so that the gas between the first sealing assembly and the second sealing assembly can be selectively discharged and captured.

2. The two-stage seal apparatus of claim 1, wherein, It also includes an elastic element located within the gap, abutting the first end of the elastic element against the outer connector and / or the inner connector, and abutting the second end of the elastic element against the second end of the second sealing assembly. The elastic element and the pusher respectively apply opposite thrusts to the second sealing assembly to cause the second sealing assembly to reciprocate between the sealing position and the venting position.

3. A two-stage seal according to any of claims 1-2, characterized in that Both the inner and outer pole shoes have multiple pole teeth spaced apart along a first direction, and the magnetofluid is disposed on the pole teeth.

4. The two-stage seal apparatus of any of claims 1-2, wherein, The second sealing assembly further includes a first magnetic isolation ring, a second magnetic isolation ring, and a third magnetic isolation ring. The first magnetic isolation ring and the second magnetic isolation ring are both sleeved on the inner connector. The first magnetic isolation ring, the inner pole shoe, the permanent magnet, the outer pole shoe, and the second magnetic isolation ring are arranged sequentially along the first direction. The third magnetic isolation ring is sleeved on the permanent magnet, and the third magnetic isolation ring abuts against the inner pole shoe and the outer pole shoe respectively.

5. The two-stage seal apparatus of any of claims 1-2, wherein, The first sealing assembly includes a sealing ring, which is fitted onto the inner connector. The inner diameter of the sealing ring is smaller than the outer diameter of the inner connector, and the wire diameter of the sealing ring is larger than the width of the gap.

6. The two-stage seal apparatus of claim 5, wherein, The first sealing assembly further includes a retaining ring, which is sleeved on the inner connector. The sealing ring and the retaining ring are arranged sequentially from the first end of the inner connector to the second end of the inner connector, and the retaining ring abuts against the sealing ring and the inner connector respectively.

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