Magnetic powder sealing device of nuclear spent fuel post-processing equipment and magnetic powder injection method

Abstract

The invention discloses a magnetic powder sealing device and method for nuclear spent fuel post-processing equipment, the magnetic powder sealing device comprises a shell, a first pole shoe, a second pole shoe, a magnetic component and a magnetic conductive component, and two end faces of the magnetic conductive component in the axial direction of an inner cavity respectively form sealing gaps with the first pole shoe and the second pole shoe. When magnetic powder is injected into the sealing gap, the axis direction of the inner cavity is parallel to the gravity direction, and the opening of the inner cavity is upward. During assembly, the first pole shoe is assembled in the inner cavity of the shell, the pole teeth of the first pole shoe face upwards, the magnetic powder is injected into the pole teeth of the first pole shoe, then the magnetic component and the magnetic conductive component are assembled in the inner cavity, and the magnetic powder is injected above the magnetic conductive component. And after the second pole shoe and the end cover are assembled in the inner cavity of the shell, the rotating shaft drives the magnetic conductive component to rotate, so that the magnetic powder is uniformly and consistently distributed. In the assembling process, the magnetic component does not have magnetism or has weak magnetism, and finally the magnetic component is electrified or magnetized, so that the uniformity of magnetic powder injection and the sealing performance of the device can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic powder seals, and particularly relates to a magnetic powder seal device and a magnetic powder injection method for nuclear spent fuel reprocessing equipment. Background Art

[0002] Nuclear spent fuel is irradiated and used nuclear fuel, usually produced by nuclear reactors in nuclear power plants. It is highly radioactive and toxic, and rich in various non-renewable rare strategic resources such as uranium and plutonium. The sealing of its reprocessing equipment is a recognized world-class problem. When leakage occurs, it will not only cause damage to the nuclear spent fuel reprocessing equipment, directly affecting the processing efficiency of nuclear waste, but also lead to the leakage of radioactive substances during the reprocessing of nuclear spent fuel, including radioactive isotopes such as uranium, plutonium, strontium, and iodine. If leaked into the environment, it will cause irreparable serious consequences to the health of workers, the public, and the surrounding ecological environment.

[0003] Magnetic powder seals have the advantages of withstanding extreme high and low temperatures, strong pressure resistance, simple structure, high reliability, no pollution, long life, and can meet the sealing requirements in specific environments through surface modification, and are widely used in various nuclear equipment in the nuclear energy field. However, due to reasons such as a small sealing gap, the magnetic powder being a superparamagnetic substance with a response characteristic to the magnetic field, and the magnetic powder being a solid with poor fluidity compared to a liquid, when adding magnetic powder to the magnetic powder seal device, the magnetic powder will usually be adsorbed where it is injected. The magnetic powder seal structure and injection method in the related technology cannot ensure that the injected magnetic powder can be evenly adsorbed on the pole teeth to effectively fill the sealing gap, so there will be a small amount of leakage, and zero leakage of the sealed medium cannot be achieved. Even the pressure resistance of the magnetic powder seal device will be greatly reduced or the sealing effect will be completely lost. Summary of the Invention

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

[0005] For this purpose, an embodiment of the present invention provides a magnetic powder seal device for nuclear spent fuel reprocessing equipment that improves the uniformity of magnetic powder distribution and sealing performance.

[0006] An embodiment of the present invention provides a magnetic powder injection method.

[0007] The magnetic powder seal device for nuclear spent fuel reprocessing equipment according to the embodiment of the present invention includes:

[0008] A housing having an inner cavity, and one end of the housing is used to connect to nuclear spent fuel reprocessing equipment;

[0009] A rotating shaft disposed in the inner cavity, and the rotating shaft and the inner cavity are coaxially arranged;

[0010] Magnetic powder sealing assembly, the magnetic powder sealing assembly includes a first pole shoe, a second pole shoe, a magnetic component and a magnetic conduction component. The first pole shoe and the second pole shoe are arranged along the axis direction of the inner cavity and connected to the inner wall of the housing. A first chamber and a second chamber are formed between the first pole shoe and the second pole shoe. The magnetic component is arranged in the first chamber, and two magnetic poles of the magnetic component are respectively abutted against the first pole shoe and the second pole shoe. The magnetic conduction component is connected to the rotating shaft, and a partial section of the magnetic conduction component is located in the second chamber, so that sealing gaps are respectively formed between two end faces of the magnetic conduction component in the axis direction of the inner cavity and the first pole shoe and the second pole shoe. The sealing gaps are used for filling magnetic powder;

[0011] End cover, the end cover is located at one end of the housing far from the nuclear spent fuel reprocessing equipment and is fixedly connected to the housing.

[0012] The magnetic powder sealing device of the nuclear spent fuel reprocessing equipment according to the embodiment of the present invention is convenient for uniformly injecting magnetic powder during assembly, and improves the uniformity of magnetic powder distribution, so that the sealing performance of the magnetic powder sealing structure is better, and irreversible hazards caused by leakage of dangerous substances such as nuclear spent fuel are avoided.

[0013] In some embodiments, the number of the magnetic powder sealing assemblies is at least two groups.

[0014] In some embodiments, the housing includes a plurality of segmented outer shells, the plurality of segmented outer shells are sequentially connected along the axis direction of the inner cavity, two adjacent segmented outer shells are coaxially arranged and fixedly connected, and at least one of the magnetic powder sealing assemblies is arranged between each segmented outer shell and the rotating shaft.

[0015] In some embodiments, an isolation component is arranged between two adjacent groups of the magnetic powder sealing assemblies, and the isolation component includes a magnetic isolation ring and / or a gasket.

[0016] In some embodiments, the end cover and the housing are positioned by a rabbet, and the end cover abuts against the adjacent magnetic powder sealing assembly; one end of the housing far from the end cover and the nuclear spent fuel reprocessing equipment are positioned by a rabbet, and one end of the housing far from the end cover has a first positioning portion, and the first positioning portion is used for abutting and positioning with the adjacent magnetic powder sealing assembly.

[0017] In some embodiments, the magnetic component is a permanent magnet or an electromagnet;

[0018] And / or, a sealing member is further included, and the sealing member is arranged between the first pole shoe and the inner wall of the housing, between the second pole shoe and the inner wall of the housing, and between the magnetic conduction component and the outer wall of the rotating shaft;

[0019] And / or, a second positioning portion is provided on the first pole shoe and the second pole shoe, and the second positioning portion is used for positioning the magnetic component disposed in the first chamber;

[0020] And / or, a plurality of pole teeth are arranged radially along the inner cavity on the first pole shoe and the second pole shoe, and the magnetic conduction component has positioning marks corresponding to the pole teeth in the corresponding first pole shoe and / or the second pole shoe on the end surface in the axial direction of the inner cavity.

[0021] The magnetic powder injection method according to an embodiment of the present invention is used for injecting magnetic powder into the sealing gap of the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment described in any one of the above embodiments, and the magnetic powder injection method includes:

[0022] S1. Install the housing and the rotating shaft in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment on the nuclear spent fuel reprocessing equipment, and one end of the inner cavity of the housing away from the nuclear spent fuel reprocessing equipment opens upward in the direction of gravity;

[0023] S2. Assemble the first pole shoe in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the housing, and inject magnetic powder into the space above the pole teeth of the first pole shoe to form multiple magnetic powder O-rings;

[0024] S3. Assemble the magnetic component and the magnetic conduction component in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the housing. The magnetic component has no magnetism or the magnetic field strength of the magnetic component is less than a first threshold value, and magnetic powder is injected into the position corresponding to the pole teeth in the second pole shoe above the magnetic conduction component to form multiple magnetic powder O-rings;

[0025] S4. Assemble the second pole shoe in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the housing;

[0026] S5. Connect the end cover to the housing;

[0027] S6. Drive the rotating shaft to rotate to drive the magnetic conduction component to rotate relative to the first pole shoe and the second pole shoe;

[0028] S7. Energize or magnetize the magnetic component so that the magnetic field strength of the magnetic component reaches a second threshold value, where the second threshold value is greater than the first threshold value.

[0029] In some embodiments, the number of magnetic powder sealing assemblies in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment is multiple;

[0030] Before step S5, the following steps are further included:

[0031] Place the isolation component into the inner cavity of the housing to isolate the assembled second pole shoe from the magnetic powder sealing assembly located above it. Repeat steps S2 to S4 to complete the assembly of the next magnetic powder sealing assembly and the injection of magnetic powder.

[0032] Repeat the previous step until the assembly of all magnetic powder sealing assemblies and the injection of magnetic powder are completed.

[0033] In some embodiments, the width of the magnetic powder O-ring is 0.2 mm to 0.4 mm, and the height of the magnetic powder O-ring is 0.1 mm to 0.2 mm.

[0034] In some embodiments, in step S6, the rotation speed of the rotating shaft is 0.05 r / s to 1 r / s, and the rotating shaft rotates 1 to 5 revolutions. Description of the Drawings

[0035] Figure 1 is a schematic diagram of the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment according to an embodiment of the present invention.

[0036] Figure 2 is a schematic diagram of the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment according to another embodiment of the present invention.

[0037] Figure 3 is a schematic diagram of the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment according to still another embodiment of the present invention.

[0038] Figure 4 is a schematic diagram of the state of injecting magnetic powder onto the first pole shoe according to an embodiment of the present invention.

[0039] Figure 5 is Figure 4 the schematic diagram in the A-A direction in

[0040] Figure 6 is a flowchart of the magnetic powder injection method according to an embodiment of the present invention.

[0041] Reference Signs:

[0042] 1. Housing; 11. Segmented outer shell; 12. Stopper; 13. First positioning portion;

[0043] 2. Rotating shaft;

[0044] 31. First pole shoe; 32. Second pole shoe; 33. Magnetic component; 34. Magnetic conduction component; 35. Seal; 36. First chamber; 37. Second chamber; 38. Second positioning portion; 39. Pole teeth;

[0045] 4. End cover;

[0046] 51. Magnetic isolation ring; 52. Washer;

[0047] 6. Magnetic powder;

[0048] 7. Nuclear spent fuel reprocessing equipment. Detailed implementation manners

[0049] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0050] As Figures 1 to 3 shown, the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment in the embodiment of the present invention includes a housing 1, a rotating shaft 2, a magnetic powder sealing assembly, and an end cover 4. The magnetic powder sealing device of the nuclear spent fuel reprocessing equipment in the embodiment of the present invention can be applied to the reprocessing equipment for nuclear spent fuel, and is used for sealing substances with a relatively high risk level to avoid leakage.

[0051] The housing 1 has an inner cavity, and one end of the housing 1 is used to be connected to the nuclear spent fuel reprocessing equipment 7; the rotating shaft 2 is arranged in the inner cavity, and the rotating shaft 2 and the inner cavity are coaxially arranged. Among them, a part of the rotating shaft 2 extends out of the housing of the nuclear spent fuel reprocessing equipment 7, and the housing 1 and the magnetic powder sealing assembly of the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment seal this part of the nuclear spent fuel reprocessing equipment 7. On the premise of not affecting the normal operation of the rotating shaft 2, this part is sealed to prevent leakage.

[0052] The magnetic powder sealing assembly includes a first pole shoe 31, a second pole shoe 32, a magnetic component 33, and a magnetic conduction component 34. The first pole shoe 31 and the second pole shoe 32 are arranged along the axis direction of the inner cavity and are connected to the inner wall of the housing 1. After the first pole shoe 31 and the second pole shoe 32 are assembled on the housing 1, they are relatively fixed to the housing 1, and a seal is formed between the two. For example, the seal between the first pole shoe 31 and the housing 1 and the seal between the second pole shoe 32 and the housing 1 are achieved by setting a sealing ring, an oil seal structure, etc. A first chamber 36 and a second chamber 37 are formed between the first pole shoe 31 and the second pole shoe 32. The magnetic component 33 is arranged in the first chamber 36, and the two magnetic poles of the magnetic component 33 are respectively abutted against the first pole shoe 31 and the second pole shoe 32. The magnetic conduction component 34 is connected to the rotating shaft 2, and a part of the magnetic conduction component 34 is located in the second chamber 37, so that two end faces of the magnetic conduction component 34 in the axis direction of the inner cavity respectively form a sealing gap with the first pole shoe 31 and the second pole shoe 32. The sealing gap is used to fill magnetic powder, and the magnetic component 33 can form a magnetic field at the sealing gap through the first pole shoe 31 and the second pole shoe 32, so that the magnetic powder stably aggregates here to form multiple sealing rings. The end cover 4 is located at one end of the housing 1 away from the nuclear spent fuel reprocessing equipment 7 and is fixedly connected to the housing 1, which is used to ensure the structural stability of the magnetic powder sealing assembly and is not interfered by the external environment.

[0053] The magnetic component 33 is a permanent magnet or an electromagnet. Figure 1 The structural diagram in which the magnetic component 33 is an electromagnet is shown. Figure 2 The structural diagram in which the magnetic component 33 is a permanent magnet is shown.

[0054] In the embodiment of the present invention, through the structural design of the magnetic powder sealing assembly, the first pole shoe 31, the magnetic conduction component 34, and the second pole shoe 32 can be sequentially assembled into the inner cavity along the axial direction of the inner cavity. When the axial direction of the inner cavity is parallel to the vertical direction, magnetic powder can be injected onto the horizontal end surface of the pole shoe or the magnetic conduction component 34. When injecting the magnetic powder 6, the magnetic component 33 can be made non-magnetic or weakly magnetic first, to avoid the situation where the magnetic powder is adsorbed wherever it is injected, which facilitates the more uniform formation of an annular sealing structure during the injection of magnetic powder. Then, after the assembly is completed, the magnetic component 33 is powered on or magnetized. For example, when the magnetic component 33 is an electromagnet, it is not powered on at this time and is powered on after the injection of magnetic powder is completed. Another example is that when the magnetic component 33 is a permanent magnet, the permanent magnet is not magnetized and is magnetized after the injection of magnetic powder is completed.

[0055] Specifically, first place the first pole shoe 31, inject magnetic powder onto the horizontal end surface of the first pole shoe 31, then assemble the magnetic conduction component 34 and the magnetic component 33, inject magnetic powder onto the horizontal end surface of the magnetic conduction component 34, and finally assemble the second pole shoe 32 into the inner cavity. In this way, when the magnetic component 33 is non-magnetic or weakly magnetic, the injection of magnetic powder can be carried out, and the injection position of the magnetic powder is guaranteed to be accurate, and the injection amount and distribution of the magnetic powder are uniform.

[0056] The magnetic powder sealing device of the spent nuclear fuel reprocessing equipment in the embodiment of the present invention facilitates the uniform injection of magnetic powder during assembly, improves the uniformity of the magnetic powder distribution, makes the sealing performance of the magnetic powder sealing structure better, and avoids irreparable harm caused by the leakage of dangerous substances such as spent nuclear fuel.

[0057] As Figure 1 and Figure 2 shown, in some embodiments, the structure of the magnetic powder sealing device of the spent nuclear fuel reprocessing equipment is the same as that of the previous embodiment. The difference is that the number of magnetic powder sealing assemblies is at least two groups, and an isolation component is provided between adjacent two groups of magnetic powder sealing assemblies. The isolation component includes a magnetic isolation ring 51 and / or a gasket 52. For example, a magnetic isolation ring 51 is provided between the pole shoes of adjacent two groups of magnetic powder sealing assemblies, and a gasket 52 is provided between the magnetic conduction components 34 of adjacent two groups of magnetic powder sealing assemblies. This ensures that the two magnetic powder sealing assemblies are relatively independent and do not affect each other, and improves the structural stability of the assembly.

[0058] During assembly, multiple magnetic powder sealing assemblies can be sequentially assembled.

[0059] As Figures 1 to 3 shown, some specific embodiments of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0060] A magnetic powder sealing device for a nuclear spent fuel reprocessing device includes a housing 1, a rotating shaft 2, a magnetic powder sealing assembly, and an end cover 4. The magnetic powder sealing device of the nuclear spent fuel reprocessing device in the embodiments of the present invention can be applied to a nuclear spent fuel reprocessing device for sealing substances with a relatively high danger level to avoid leakage.

[0061] As Figure 3 shown, the housing 1 includes a plurality of segmented outer shells 11, and the plurality of segmented outer shells 11 are sequentially connected along the axis direction of the inner cavity. Two adjacent segmented outer shells 11 are coaxially arranged and fixedly connected. At least one magnetic powder sealing assembly is provided between each segmented outer shell 11 and the rotating shaft 2. For example, the housing 1 includes two segmented outer shells 11, and a set of magnetic powder sealing assemblies are provided in each segmented outer shell 11.

[0062] The interiors of the plurality of segmented outer shells 11 are hollow and configured as the inner cavity of the housing 1. One end of the housing 1 is used to be connected to the nuclear spent fuel reprocessing device 7; the rotating shaft 2 is arranged in the inner cavity, and the rotating shaft 2 and the inner cavity are coaxially arranged. Among them, the rotating shaft 2 is arranged in the nuclear spent fuel reprocessing device 7, and a part of the rotating shaft 2 extends out of the outer shell of the nuclear spent fuel reprocessing device 7. The housing 1 and the magnetic powder sealing assembly of the magnetic powder sealing device of the nuclear spent fuel reprocessing device seal this part of the nuclear spent fuel reprocessing device 7. On the premise of not affecting the normal operation of the rotating shaft 2, this part is sealed to prevent leakage.

[0063] The end cover 4 is located at one end of the housing 1 away from the nuclear spent fuel reprocessing device 7 and is fixedly connected to the housing 1 to ensure the structural stability of the magnetic powder sealing assembly and is not interfered by the external environment. Specifically, after the magnetic powder sealing assembly is assembled in the housing 1, the end cover 4 is connected to one end of the housing 1 away from the nuclear spent fuel reprocessing device 7. The end cover 4 and the housing 1 are positioned by a spigot 12. The end cover 4 abuts against the pole shoe in the adjacent magnetic powder sealing assembly, which can ensure the fixation of the magnetic powder sealing assembly and prevent the magnetic powder sealing assembly from moving; one end of the housing 1 away from the end cover 4 and the nuclear spent fuel reprocessing device 7 are positioned by a spigot 12. One end of the housing 1 away from the end cover 4 has a first positioning portion 13, and the first positioning portion 13 is used to abut and position with the adjacent magnetic powder sealing assembly. The first positioning portion 13 can be a stepped limiting end face provided on the wall surface of the inner cavity of the housing 1. When the pole shoe closest to the limiting end face is assembled into the inner cavity, it can abut against the limiting end face to achieve positioning.

[0064] The number of magnetic powder seal components is multiple. Each magnetic powder seal component includes a first pole shoe 31, a second pole shoe 32, a magnetic component 33, and a magnetic conduction component 34. As shown in the figure, in the up-and-down direction, a magnetic isolation ring 51 is provided between the first pole shoe 31 of the upper magnetic powder seal component and the second pole shoe 32 of the lower magnetic powder seal component, and a washer 52 is provided between the magnetic conduction components 34 of the upper magnetic powder seal component and the lower magnetic powder seal component to achieve the isolation of adjacent magnetic powder seal components and ensure the stability of the structure after assembly. The first pole shoe 31 and the second pole shoe 32 are arranged along the axis direction of the inner cavity and connected to the inner wall of the housing 1. After the first pole shoe 31 and the second pole shoe 32 are assembled on the housing 1, they are relatively fixed to the housing 1 and sealed between them. For example, seals 35 are provided between the first pole shoe 31 and the inner wall of the housing 1, between the second pole shoe 32 and the inner wall of the housing 1, and between the magnetic conduction component 34 and the outer wall of the rotating shaft 2; the seal 35 can be an O-ring, an oil seal structure, etc. to achieve the seal between the first pole shoe 31 and the housing 1 and the seal between the second pole shoe 32 and the housing 1. A first chamber 36 and a second chamber 37 are formed between the first pole shoe 31 and the second pole shoe 32. The magnetic component 33 is arranged in the first chamber 36, and the two magnetic poles of the magnetic component 33 are respectively abutted against the first pole shoe 31 and the second pole shoe 32. Specifically, second positioning portions 38 are provided on the first pole shoe 31 and the second pole shoe 32. The second positioning portions 38 can be sunk grooves or sunk platforms provided on the first pole shoe 31 and the second pole shoe 32. The second positioning portions 38 are used to position the magnetic component 33 arranged in the first chamber 36 to ensure that the magnetic component 33 does not shake.

[0065] The magnetic conduction component 34 can be a magnetic conduction sleeve. The magnetic conduction component 34 is connected to the rotating shaft 2. The magnetic conduction component 34 can be connected to the rotating shaft 2 through structures such as threads and key grooves, and a seal ring can also be provided between the magnetic conduction component 34 and the rotating shaft 2 to ensure that there is no leakage at the contact surface between the magnetic conduction component 34 and the rotating shaft 2. A partial section of the magnetic conduction component 34 is located in the second chamber 37 so that sealing gaps are respectively formed between the two end faces of the magnetic conduction component 34 in the axis direction of the inner cavity and the first pole shoe 31 and the second pole shoe 32. The sealing gaps are used to fill magnetic powder.

[0066] The magnetic component 33 can form a magnetic field at the sealing gap through the first pole shoe 31 and the second pole shoe 32, so that the magnetic powder stably aggregates here to form multiple sealing rings.

[0067] Further, the first pole shoe 31 and the second pole shoe 32 are provided with a plurality of pole teeth 39 arranged radially along the inner cavity. The magnetic field intensity at the pole teeth 39 is much stronger than that at the tooth grooves on both sides of the pole teeth 39. Since magnetic powder has a response characteristic to the magnetic field, the magnetic powder will be firmly adsorbed in the sealing gap at the pole teeth 39, effectively filling the sealing gap to form a magnetic powder "O"-shaped sealing ring, ensuring zero leakage of the magnetic powder seal. The magnetic conductive component 34 has positioning marks corresponding to the pole teeth 39 in the corresponding first pole shoe 31 and / or second pole shoe 32 on the end face in the axial direction of the inner cavity.

[0068] In the embodiment of the present invention, through the structural design of the magnetic powder seal assembly, the first pole shoe 31, the magnetic conductive component 34, and the second pole shoe 32 can be sequentially assembled into the inner cavity along the axial direction of the inner cavity. When the axial direction of the inner cavity is parallel to the vertical direction, magnetic powder can be injected onto the horizontal end face of the pole shoe or the magnetic conductive component 34. When injecting magnetic powder, the magnetic component 33 can be made non-magnetic or weakly magnetic first to avoid the situation where the magnetic powder is adsorbed wherever it is injected during injection, facilitating the formation of a more uniform annular sealing structure during magnetic powder injection. Then, after the assembly is completed, the magnetic component 33 is energized or magnetized. Specifically, first place the first pole shoe 31, inject magnetic powder onto the horizontal end face of the first pole shoe 31, then assemble the magnetic conductive component 34 and the magnetic component 33, and then inject magnetic powder onto the horizontal end face of the magnetic conductive component 34. At this time, the injection position of the magnetic powder can be determined according to the positioning marks to ensure that the position of the injected magnetic powder corresponds to the pole teeth 39 of the second pole shoe 32. Finally, assemble the second pole shoe 32 into the inner cavity. In this way, magnetic powder can be injected when the magnetic component 33 is non-magnetic or weakly magnetic, and the injection position of the magnetic powder is ensured to be accurate, and the injection amount and distribution of the magnetic powder are uniform. After the magnetic component 33 is energized or magnetized, the magnetic powder is firmly adsorbed at the pole teeth 39 by the magnetic field, and the distribution of the magnetic powder is ensured to be uniform.

[0069] The magnetic powder seal device of the spent nuclear fuel reprocessing equipment in the embodiment of the present invention facilitates the uniform injection of magnetic powder during assembly, improves the uniformity of the magnetic powder distribution, makes the sealing performance of the magnetic powder seal structure better, and avoids irreparable harm caused by the leakage of dangerous substances such as spent nuclear fuel.

[0070] As Figures 4 to 6 shown, the magnetic powder injection method in the embodiment of the present invention is used to inject magnetic powder into the sealing gap in the magnetic powder seal device of the spent nuclear fuel reprocessing equipment in any one of the above embodiments. The magnetic powder injection method includes:

[0071] S1. Install the housing 1 and the rotating shaft 2 in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment on the nuclear spent fuel reprocessing equipment 7. One end of the inner cavity of the housing 1 away from the nuclear spent fuel reprocessing equipment 7 opens upward in the direction of gravity. The up and down directions in the figure are the directions of gravity. The housing 1 and the nuclear spent fuel reprocessing equipment 7 are positioned by the spigot 12 and fixedly connected by connecting parts such as bolts.

[0072] S2. Assemble the first pole shoe 31 in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the housing 1, and inject magnetic powder into the space above the pole teeth 39 of the first pole shoe 31 to form multiple magnetic powder O-rings. As Figure 4 and Figure 5 shown, usually, multiple concentric pole teeth 39 distributed radially along the rotating shaft 2 are arranged on the first pole shoe 31. An appropriate amount of magnetic powder is evenly injected into the space above each pole tooth 39 to form multiple magnetic powder O-rings. The width of the magnetic powder O-ring is 0.2 mm to 0.4 mm. For example, the width of the magnetic powder O-ring is 0.3 mm, and the height of the magnetic powder O-ring is 0.1 mm to 0.2 mm.

[0073] S3. Assemble the magnetic component 33 and the magnetic conductive component 34 in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the housing 1. The magnetic component 33 has no magnetism or the magnetic field strength of the magnetic component 33 is less than the first threshold. The magnetic field strength of the magnetic component 33 needs to be non-magnetic or weakly magnetic, and it will not cause the magnetic powder to be directly adsorbed at the pole teeth 39 when the magnetic powder is injected. Magnetic powder is injected into the position corresponding to the pole teeth 39 in the second pole shoe 32 above the magnetic conductive component 34 to form multiple magnetic powder O-rings. The magnetic component 33 is positioned relative to the second positioning portion 38 (the sunk groove or the sunk platform provided on the first pole shoe 31) on the first pole shoe 31. When there is a positioning mark on the magnetic conductive component 34, the magnetic powder can be injected according to the positioning mark to ensure that the injection position corresponds to the position of the pole teeth 39 on the second pole shoe 32. The width of the magnetic powder O-ring is 0.2 mm to 0.4 mm. For example, the width of the magnetic powder O-ring is 0.3 mm, and the height of the magnetic powder O-ring is 0.1 mm to 0.2 mm.

[0074] S4. Assemble the second pole shoe 32 in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the housing 1. In steps S2 and S3, the injection height of the magnetic powder O-ring can be slightly higher than the height of the sealing gap. In this way, after the assembly is completed, the magnetic powder O-ring can be squeezed to a certain extent, thereby improving the compactness of the magnetic powder.

[0075] S5. Connect the end cover 4 to the housing 1. The end cover 4 and the housing 1 are positioned by the spigot 12 and fixedly connected by connecting parts such as bolts. The end cover 4 can also be abutted against the second pole shoe 32, thereby ensuring that the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment does not move.

[0076] S6. Rotate the driving rotating shaft 2 to drive the magnetic conduction component 34 to rotate relative to the first pole shoe 31 and the second pole shoe 32. The rotation speed of the rotating shaft 2 is 0.05 r / s to 1 r / s, and the rotating shaft 2 rotates 1 to 5 weeks. This is used to make the magnetic powder distribution in each magnetic powder O-ring more uniform and ensure no leakage occurs.

[0077] S7. Energize or magnetize the magnetic component 33 so that the magnetic field intensity of the magnetic component 33 reaches a second threshold value, where the second threshold value is greater than the first threshold value. The second threshold value is much greater than the first threshold value. When the magnetic field intensity reaches the second threshold value, the magnetic powder can be stably adsorbed at the pole teeth 39 to form a seal. For example, when the magnetic component 33 is an electromagnet, the magnetic field intensity can be controlled by energizing. In steps S3 to S6, the electromagnet is not energized, and in step S7, it is energized. Another example is that when the magnetic component 33 is a permanent magnet, in steps S3 to S6, the permanent magnet has no magnetism or only weak magnetism, and in step S7, the permanent magnet is magnetized.

[0078] In some embodiments, the number of magnetic powder seal assemblies in the magnetic powder seal device of the nuclear spent fuel reprocessing equipment is multiple; the magnetic powder injection method in this embodiment is basically the same as that in the previous embodiment. The difference is that before performing the operation of step S5, the following steps are further included:

[0079] Place the isolation component (magnetic isolation ring 51) into the inner cavity of the housing 1 to isolate the assembled second pole shoe 32 from the magnetic powder seal assembly located above it. Repeat steps S2 to S4 to complete the assembly of the next magnetic powder seal assembly and the injection of magnetic powder. At this time, the assembly of the second magnetic powder seal assembly is completed;

[0080] When there are more than three magnetic powder seal assemblies, the above step can be repeated until the assembly of all magnetic powder seal assemblies and the injection of magnetic powder are completed.

[0081] In some embodiments, the method for injecting magnetic powder in this embodiment is basically the same as that in the above embodiments. The difference is that when the housing 1 includes a plurality of segmented outer shells 11 and the number of magnetic powder sealing assemblies is plural, then in step S1, the plurality of segmented outer shells 11 can be connected in sequence first, and then assembled on the nuclear spent fuel reprocessing equipment 7. If a first positioning portion 13 (a stepped limiting end face) is provided in each of the segmented outer shells 11, then in step S1, the segmented outer shell 11 closest to the nuclear spent fuel reprocessing equipment 7 needs to be installed on the nuclear spent fuel reprocessing equipment 7 first, and the operations of S2 to S4 are performed to complete the installation of the magnetic powder sealing assembly corresponding to this segmented outer shell 11. Then the next segmented outer shell 11 is installed, and the operations of S2 to S4 are performed, and the installation of the plurality of segmented outer shells 11 and their corresponding magnetic powder sealing assemblies are carried out in sequence. Finally, the operations of steps S5 to S7 are performed.

[0082] In the embodiments of the present invention, the magnetic field strength generated by the magnetic component as the magnetic source during the magnetic powder injection process is 0 or extremely small, and the adsorption force on the magnetic powder is almost 0, solving the technical problem that the magnetic powder "adsorbs wherever it is injected" during the magnetic powder injection due to the response characteristic of the magnetic powder as a superparamagnetic substance to the magnetic field, and ensuring the uniformity of the magnetic powder injection.

[0083] In the embodiments of the present invention, the magnetic powder injection process is carried out synchronously with the installation and assembly process of the device. When injecting magnetic powder above the first pole shoe or the magnetic conduction component, there is sufficient space above the first pole shoe and the magnetic conduction component for adding magnetic powder, and the position and state of the magnetic powder after injection can be clearly observed, facilitating timely adjustment of the magnetic powder, solving the technical problem that it is difficult to effectively inject magnetic powder due to the small sealing gap, and ensuring the accuracy of the magnetic powder injection.

[0084] After the installation of the magnetic powder sealing assembly is completed, by driving the rotation of the rotating shaft, the magnetic conduction component (magnetic conduction sleeve) is driven to rotate synchronously. For example, relying on the tooling to drive the rotating shaft and the magnetic conduction component to slowly rotate at a speed of 0.05 - 1 r / s for 1 to 5 weeks can drive the circumferential movement of the magnetic powder, solving the technical problem that it is difficult to uniformly inject magnetic powder due to the poor fluidity of the magnetic powder as a solid compared to a liquid, and being beneficial to the more uniform formation of the magnetic powder O-ring.

[0085] In the embodiments of the present invention, the magnetic component can be an electromagnet or a permanent magnet. After the magnetic powder sealing assembly is assembled and the magnetic powder is more evenly distributed when the rotating shaft rotates, by passing a strong current through the electromagnet or magnetizing the permanent magnet, a magnetic circuit is formed among the magnetic component, the pole shoe, and the magnetic conduction component. Since the gap between the pole teeth and the magnetic conduction component (generally 0.1 - 0.2 mm) is much smaller than the gap between the tooth grooves on both sides of the pole teeth and the magnetic conduction sleeve, the magnetic field intensity at the pole teeth will be much stronger than that at the tooth grooves on both sides of the pole teeth. The magnetic powder has a response characteristic to the magnetic field, and the magnetic powder will be firmly adsorbed in the sealing gap at the pole teeth. The height of the magnetic powder injection is consistent with the size of the sealing gap, avoiding waste of the magnetic powder and effectively filling the sealing gap to form a magnetic powder "O"-shaped sealing ring, ensuring zero leakage of the magnetic powder seal.

[0086] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0087] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0088] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communicable with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0089] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Further, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0090] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0091] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill 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 powder sealing device for nuclear spent fuel reprocessing equipment, characterized in that: include: A shell having an inner cavity, one end of which is used to be connected to a nuclear spent fuel reprocessing device; A rotating shaft, wherein the rotating shaft is disposed in the inner cavity, and the rotating shaft and the inner cavity are coaxially arranged; A magnetic powder sealing assembly, the magnetic powder sealing assembly comprising a first pole shoe, a second pole shoe, a magnetic component and a magnetic conductive component, the first pole shoe and the second pole shoe are arranged along the axial direction of the inner cavity and connected to the inner wall of the shell, a first chamber and a second chamber are formed between the first pole shoe and the second pole shoe, the magnetic component is arranged in the first chamber and the two magnetic poles of the magnetic component are respectively abutted against the first pole shoe and the second pole shoe, the magnetic conductive component is connected to the rotating shaft, and a partial section of the magnetic conductive component is located in the second chamber, so that two end surfaces of the magnetic conductive component in the axial direction of the inner cavity respectively form a sealing gap with the first pole shoe and the second pole shoe, and the sealing gap is used to fill magnetic powder; The end cover is located at one end of the shell away from the nuclear spent fuel reprocessing equipment and is fixedly connected to the shell.

2. The magnetic powder sealing device for nuclear spent fuel reprocessing equipment according to claim 1, characterized in that: The number of the magnetic powder sealing components is at least two.

3. The magnetic powder sealing device for nuclear spent fuel reprocessing equipment according to claim 2, characterized in that: The shell includes a plurality of segmented outer shells, which are connected in sequence along the axial direction of the inner cavity, two adjacent segmented outer shells are coaxially arranged and fixedly connected, and at least one magnetic powder sealing assembly is provided between each segmented outer shell and the rotating shaft.

4. The magnetic powder sealing device for nuclear spent fuel reprocessing equipment according to claim 2, characterized in that: An isolation component is arranged between two adjacent groups of the magnetic powder sealing components, and the isolation component includes a magnetic isolation ring and / or a gasket.

5. The magnetic powder sealing device for nuclear spent fuel reprocessing equipment according to claim 1, characterized in that: The end cover and the shell are positioned by a stopper, and the end cover abuts against the adjacent magnetic powder seal assembly; the end of the shell away from the end cover is positioned with the nuclear spent fuel reprocessing equipment by a stopper, and the end of the shell away from the end cover has a first positioning portion, and the first positioning portion is used to abut and position with the adjacent magnetic powder seal assembly.

6. The magnetic powder sealing device of the nuclear spent fuel reprocessing equipment according to any one of claims 1 to 5, characterized in that: The magnetic component is a permanent magnet or an electromagnet; And / or, further comprising a seal, wherein the seal is disposed between the first pole shoe and the inner wall of the housing, between the second pole shoe and the inner wall of the housing, and between the magnetic conductive component and the outer wall of the rotating shaft; And / or, the first pole shoe and the second pole shoe are provided with a second positioning portion, and the second positioning portion is used to position the magnetic component arranged in the first chamber; And / or, the first pole shoe and the second pole shoe have a plurality of pole teeth arranged radially along the inner cavity, and the magnetic conductive component has positioning marks on the end face in the axial direction of the inner cavity corresponding to the pole teeth in the corresponding first pole shoe and / or second pole shoe.

7. A magnetic powder injection method, characterized in that: The method for injecting magnetic powder into a sealing gap of a magnetic powder sealing device of a nuclear spent fuel reprocessing device according to any one of claims 1 to 6 comprises: S1. Installing the shell and the rotating shaft of the magnetic powder sealing device of the spent fuel reprocessing equipment on the spent fuel reprocessing equipment, with the inner cavity of the shell opening at one end away from the spent fuel reprocessing equipment facing upward in the direction of gravity; S2, assembling the first pole shoe in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the shell, and injecting magnetic powder into the space above the pole teeth of the first pole shoe to form a plurality of magnetic powder O-rings; S3, assembling the magnetic component and the magnetic conductive component in the magnetic powder sealing device of the spent nuclear fuel reprocessing equipment in the inner cavity of the shell, wherein the magnetic component is non-magnetic or the magnetic field strength of the magnetic component is less than a first threshold value, and injecting magnetic powder at a position above the magnetic conductive component corresponding to the pole teeth in the second pole shoe to form a multi-channel magnetic powder O-ring; S4, assembling the second pole piece in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment into the inner cavity of the shell; S5, connecting the end cover to the housing; S6, driving the rotating shaft to rotate, so as to drive the magnetic conductive component to rotate relative to the first pole shoe and the second pole shoe; S7. Power on or magnetize the magnetic component so that the magnetic field strength of the magnetic component reaches a second threshold, wherein the second threshold is greater than the first threshold.

8. The magnetic powder injection method according to claim 7, characterized in that: The number of magnetic powder sealing components in the magnetic powder sealing device of the nuclear spent fuel reprocessing equipment is multiple; Before step S5, the following steps are also included: Placing an isolation component into the inner cavity of the housing to isolate the assembled second pole piece from the magnetic powder sealing assembly located above the second pole piece, and repeating steps S2 to S4 to complete the assembly of the next magnetic powder sealing assembly and the injection of magnetic powder; Repeat the previous step until all magnetic powder seal components are assembled and magnetic powder is injected.

9. The magnetic powder injection method according to claim 7, characterized in that: The width of the magnetic powder O-ring is 0.2 mm to 0.4 mm, and the height of the magnetic powder O-ring is 0.1 mm to 0.2 mm.

10. The magnetic powder injection method according to claim 7, characterized in that: In step S6, the rotation speed of the rotating shaft is 0.05 r / s to 1 r / s, and the rotating shaft rotates 1 to 5 times.

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