A high-temperature shielded molten salt pump supported by a magnetic bearing

Abstract

The present invention relates to a high-temperature shielded molten salt pump supported by a magnetic bearing, comprising a rotating assembly with a main shaft and a bearing cylinder, a connecting cylinder and an annular pump body arranged in sequence from top to bottom, wherein the main shaft passes through the connecting cylinder and extends to the inside of the bearing cylinder and the annular pump body, and further comprising: a first cover plate, which is sealed and connected to the top of the bearing cylinder; a magnetic bearing group, which is arranged inside the bearing cylinder, and comprises an upper radial magnetic bearing, an axial thrust magnetic bearing and a lower radial magnetic bearing; a shielded motor, which is arranged between the axial thrust magnetic bearing and the lower radial magnetic bearing; and a shielding plug, which is arranged inside the connecting cylinder. The present invention makes the overall structure of the molten salt pump compact and runs smoothly, and can achieve the effect of completely isolating the internal and external atmosphere environments, and is convenient and efficient to maintain.

Description

Technical Field

[0001] The invention relates to the field of molten salt pumps, and more specifically to a high-temperature shielded molten salt pump supported by a magnetic suspension bearing. Background Art

[0002] The high-temperature molten salt pump is a heat transfer medium driving device in a molten salt reactor or molten salt heat storage project. It is used to overcome the system resistance of the loop and is the heart of the loop system. At present, the high-temperature molten salt pump commonly used in molten salt reactors or molten salt heat storage projects is a vertical submersible pump driven by an independent motor. However, this molten salt pump has many disadvantages: First, it is connected to an independent motor by a coupling, making the overall structure longer. Second, the independent motor and the pump body have their own bearings, which will generate more noise and cause greater vibration, resulting in unstable operation. In addition, the bearings require auxiliary measures such as oil cooling, and more bearings will make the overall structure maintenance complicated. Third, the sealing performance is poor, and the atmosphere inside and outside the pump body cannot be completely isolated. At the same time, the sealing requires the addition of an additional dynamic sealing structure.

[0003] Therefore, in order to meet the requirements of safe and reliable transportation of molten salt medium, it is necessary to develop a molten salt pump with compact structure, stable and reliable operation, easy maintenance and good internal and external atmosphere isolation performance. Summary of the invention

[0004] In order to solve the above problems in the prior art, the present invention provides a high-temperature shielded molten salt pump supported by a magnetic bearing to meet the requirements of compact structure, stable and reliable operation, convenient maintenance and good internal and external atmosphere isolation performance.

[0005] The present invention provides a high-temperature shielded molten salt pump supported by a magnetic bearing, comprising a rotating assembly with a main shaft and a bearing cylinder, a connecting cylinder and an annular pump body arranged in sequence from top to bottom, wherein the main shaft passes through the connecting cylinder and extends to the interior of the bearing cylinder and the annular pump body, and further comprises: a first cover plate, sealingly connected to the top of the bearing cylinder; a magnetic bearing group, arranged inside the bearing cylinder, comprising an upper radial magnetic bearing, an axial thrust magnetic bearing and a lower radial magnetic bearing; a shielded motor, arranged between the axial thrust magnetic bearing and the lower radial magnetic bearing; a shielding plug, arranged inside the connecting cylinder.

[0006] Furthermore, an upper radial magnetic bearing rotor, an axial thrust magnetic bearing rotor, a shielded motor rotor and a lower radial magnetic bearing rotor are sequentially installed in the middle and upper part of the main shaft from top to bottom, and an impeller is provided at the lower part.

[0007] Furthermore, a first sleeve and a second sleeve are provided on the upper side of the upper radial magnetic bearing rotor and between the upper radial magnetic bearing rotor and the axial thrust magnetic bearing rotor, and a third sleeve and a fourth sleeve are provided between the axial thrust magnetic bearing rotor and the shielded motor rotor and between the shielded motor rotor and the lower radial magnetic bearing rotor.

[0008] Furthermore, the bearing cylinder is welded by a first outer shell, a first inner shell and a first flange, and a cooling channel is provided between the first outer shell and the first inner shell.

[0009] Furthermore, the interior of the first inner shell is arranged with an upper radial magnetic bearing stator, an axial thrust magnetic bearing stator, a shielded motor stator and a lower radial magnetic bearing stator from top to bottom, the upper radial magnetic bearing stator and the axial thrust magnetic bearing stator are located in the first inner shell in sequence, and the lower radial magnetic bearing stator is installed inside the first flange by bolts.

[0010] Furthermore, a shielding sleeve is provided on the stator of the shielded motor, the upper part of the shielding sleeve is connected to the lower end surface of the axial thrust magnetic bearing stator, and the lower part is connected to the upper end surface of the lower radial magnetic bearing stator.

[0011] Furthermore, the axial thrust magnetic bearing comprises a first component, a second component and a thrust plate, and the magnetic area of ​​the first component and the thrust plate is larger than the magnetic area of ​​the second component and the thrust plate.

[0012] Furthermore, an upper protective bearing is provided above the upper radial magnetic bearing, and a lower protective bearing is provided below the lower radial magnetic bearing.

[0013] Furthermore, the upper protection bearing and the upper radial magnetic bearing stator share a bearing housing, and the lower protection bearing and the lower radial magnetic bearing stator share a bearing housing.

[0014] Furthermore, an axial distance between the axial thrust magnetic suspension bearing and the upper protective bearing is less than or equal to twice the thickness of the upper radial magnetic bearing.

[0015] Furthermore, the shielding plug is welded by a fifth flange, a second outer shell, a second inner shell, a partition and a shielding block, and has a plurality of shielding chambers, and the shielding chambers are filled with heat insulation materials.

[0016] The present invention adopts a built-in shielded motor and a frictionless magnetic bearing that can reduce the axial size, so that the overall structure of the molten salt pump is compact and runs smoothly. The high-temperature shielded molten salt pump supported by the magnetic bearing of the present invention adopts a static seal, and can achieve the effect of completely isolating the internal and external atmospheres. In addition, the magnetic bearing of the present invention is easy to disassemble, making maintenance convenient and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a high-temperature shielded molten salt pump supported by a magnetic suspension bearing according to the present invention.

[0018] Figure 2 yes Figure 1 Schematic diagram of the structure of the rotating component.

[0019] Figure 3 yes Figure 1 Schematic diagram of the structure of the middle bearing cylinder.

[0020] Figure 4 yes Figure 1 Schematic diagram of the structure of the medium radial magnetic bearing.

[0021] Figure 5 yes Figure 1 Schematic diagram of the structure of the mid-axial thrust magnetic bearing.

[0022] Figure 6 This is a working principle diagram of the magnetic levitation system.

[0023] Figure 7 yes Figure 1 Schematic diagram of the structure of the connecting cylinder.

[0024] Figure 8 yes Figure 1 Schematic diagram of the structure of the medium annular pump body. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0026] like Figure 1 As shown, a high-temperature shielded molten salt pump supported by a magnetic bearing according to a preferred embodiment of the present invention comprises a rotating assembly 1 and a bearing cylinder 2, a connecting cylinder 3 and an annular pump body 4 arranged in sequence from top to bottom, wherein the rotating assembly 1 penetrates the connecting cylinder 3 and extends to the inside of the bearing cylinder 2 and the annular pump body 4. Among them, a first cover plate 211 is provided on the bearing cylinder 2, and the first cover plate 211 is fixed to the top of the bearing cylinder 2 by bolts, and a sealing gasket 212 (such as Figure 3As shown in the figure, the first cover plate 211 and the bearing cylinder 2 form two boundaries that isolate the atmosphere inside and outside the molten salt pump. In addition, a magnetic suspension bearing group including an upper radial magnetic suspension bearing 5, an axial thrust magnetic suspension bearing 6 and a lower radial magnetic suspension bearing 7 and a shielded motor 8 are provided inside the bearing cylinder 2, and a shielding plug 9 is provided in the connecting cylinder 3.

[0027] like Figure 2 As shown, the rotating assembly 1 includes a main shaft 11, the middle and upper part of the main shaft 11 extends to the inside of the bearing cylinder 2, and the lower part extends to the inside of the annular pump body 4. The upper radial magnetic suspension bearing rotor 51, the axial thrust magnetic suspension bearing rotor 61, the shielded motor rotor 81 and the lower radial magnetic suspension bearing rotor 71 are installed in sequence from top to bottom in the middle and upper part of the main shaft 11, and the first locking nut 111 is provided at the uppermost side of the main shaft 11, and the lower part of the first locking nut 111 is provided with a bearing cover 110 of the upper protective bearing 27 and a bearing lower cover 12 of the upper protective bearing 27 (see the upper protective bearing 27). Figure 3 ). A first sleeve 13 is provided between the upper radial magnetic bearing rotor 51 and the axial thrust magnetic bearing rotor 61, a second sleeve 14 is provided between the axial thrust magnetic bearing rotor 61 and the shielded motor rotor 81, and a third sleeve 15 is provided between the shielded motor rotor 81 and the lower radial magnetic bearing rotor 71. The first sleeve 13, the second sleeve 14 and the third sleeve 15 are used to support the above-mentioned rotors 51, 61, 71, 81. These sleeves and rotors are all fitted on the main shaft 11 by interference fit, and are finally locked by the first locking nut 111 at the top of the main shaft 11. An impeller 16 is provided at the lower part of the main shaft 11, and the impeller 16 is locked on the main shaft 11 by a second locking nut 17. A button 18 is provided on the impeller 16 for transmitting torque. A fourth sleeve 19 is provided on the back of the impeller 16 for labyrinth throttling sealing of the molten salt on the back.

[0028] The bearing cylinder 2 provides a mounting location for the magnetic bearing assembly and the shielded motor 8 and cools them. Figure 3As shown, the bearing cylinder 2 is welded by a first outer shell 21, a first inner shell 22 and a first flange 23. A cooling channel is provided between the first outer shell 21 and the first inner shell 22. The externally circulated cooling medium flows into the cooling channel through the water inlet 242 and flows out through the water outlet 241, taking away the heat generated by each bearing and the shielded motor 8 when working and the heat transmitted from the lower components, so as to ensure that each bearing and the shielded motor 8 can work at a suitable temperature. In addition, in order to supply power to each device (bearing, motor, sensor, etc.) in the bearing cylinder 2, a junction box 25 is provided on the upper part of the first outer shell 21, and a wiring groove 26 is arranged symmetrically in the inner circumference of the first inner shell 22. The electrical cables of each device in the bearing cylinder 2 are arranged in the wiring groove 26, and are connected to the junction box 25 through the through hole on the upper part of the bearing cylinder 2. A sealing gasket is also provided on the electrical connector installation panel 251 inside the junction box 25 to isolate the atmosphere inside and outside the bearing cylinder 2.

[0029] The interior of the first inner shell 22 is arranged from top to bottom with an upper radial magnetic bearing stator 52, an axial thrust magnetic bearing stator 62, a shielded motor stator 82 and a lower radial magnetic bearing stator 72. The upper radial magnetic bearing stator 52 is separated from the axial thrust magnetic bearing stator 62 by a retaining ring 213, and a stepped sink is provided on the inner wall of the first inner shell 22, so that the inner diameters of the first inner shell 22 on the upper and lower sides of the sink are different, and the axial thrust magnetic bearing stator 62 is installed on the supporting surface of the sink inside the first inner shell 22. In addition, in order to prevent the molten salt vapor from corroding the electronic coil of the shielded motor 8, a shielding sleeve 83 is provided on the shielded motor stator 82, and the upper part of the shielding sleeve 83 is connected to the lower end surface of the axial thrust magnetic bearing stator 62, and the lower part is connected to the upper end surface of the lower radial magnetic bearing stator 72.

[0030] The positions of the stators 52, 62, 72, 82 correspond to the positions of the rotors 51, 61, 71, 81 installed on the main shaft 11, and there is a gap between the corresponding stators and rotors, thereby respectively forming an upper radial magnetic suspension bearing 5, an axial thrust magnetic suspension bearing 6, a lower radial magnetic suspension bearing 7 and a shielded motor 8. Among them, the upper radial magnetic suspension bearing 5 and the lower radial magnetic suspension bearing 7 provide radial force support for the rotating component 1, the axial thrust magnetic suspension bearing 6 provides axial positioning for the rotating component 1 to prevent the axial movement of the rotating component 1, and the shielded motor 8 provides power for the rotation of each rotor.

[0031] In this embodiment, an upper protective bearing 27 is provided above the upper radial magnetic bearing 5, and a lower protective bearing 28 is provided below the lower radial magnetic bearing 7. The upper protective bearing 27 and the upper radial magnetic bearing stator 52 share a bearing housing, and the lower protective bearing 28 and the lower radial magnetic bearing stator 72 share a bearing housing. The upper protective bearing 27 is placed on the upper protective bearing seat 271 and fixed by the upper protective bearing cover 272, and the upper protective bearing seat 271 is fixed to the inside of the first inner housing 22 by the end locking ring 273 through spring compression. It should be noted that the upper protective bearing seat 272 also serves as the stator housing of the upper radial magnetic bearing 5. The lower protective bearing 28 is placed on the second flange 281, which is a combined flange, which is connected to the first flange 23 by bolts, and is used to support and position the lower radial magnetic bearing 7, and serves as the bearing seat of the lower protective bearing 28, and at the same time serves as the stator housing of the lower radial magnetic bearing 7, which facilitates the disassembly and maintenance of the lower protective bearing 28. The protective bearings 27 and 28 play a role in supporting the shaft system and protecting against impact when the power is off. When the molten salt pump is running, they do not contact the magnetic suspension bearings 5, 6, and 7. Due to the upper protective bearing 27, a corresponding bearing gland 110 is provided at the end of the main shaft 11 (see Figure 2 ), and the bearing gland 110 is locked by the first locking nut 111 to withstand the axial force by protecting the bearing 27. In addition, a purge air pipe 29 is provided on the outer side of the upper end of the bearing cylinder 2, and the purge air pipe 29 purges downward along the gap between the stator and rotor components.

[0032] Combination Figure 1-Figure 3 It can be seen that the magnetic bearing group and the shielded motor 8 are arranged at a position far away from the impeller 16. This arrangement can reduce the operating temperature of each magnetic bearing and the shielded motor 8, and avoid the molten salt pump from being affected by the high-temperature medium and failing. In addition, the distance between the upper radial magnetic bearing 5 and the impeller 16 is the longest, so that when controlling the balance of the impeller 16 rotor, the force required to be applied to the impeller 16 rotor by the upper radial magnetic bearing 5 is smaller, thereby making the required current smaller and saving costs. It should be noted that in other embodiments, the positions of the upper radial magnetic bearing 5 and the axial thrust magnetic bearing 6 can also be interchanged as needed.

[0033] like Figure 4 As shown, in order to reduce eddy current as much as possible, the stator core of the radial magnetic bearing stator 52, 72 and the rotor portion opposite to the core (i.e., the radial magnetic bearing rotor 51, 71) adopt a laminated structure, and each layer is insulated. The present invention uses an 8-pole radial magnetic bearing, so that each two magnetic pole pairs can be designed according to the Cartesian coordinate system commonly used in mechanics to simplify bearing control, and the polarity on the plane perpendicular to the rotor rotation axis is a NSSNNSSN sequence or a NSNSNSNS sequence.

[0034] It should be noted that the axial length of the upper radial magnetic bearing 5 in the present invention can be less than, equal to or greater than the lower radial magnetic bearing 7. In this embodiment, the axial length of the upper radial magnetic bearing 5 is less than the axial length of the lower radial magnetic bearing 7. Because the installation position of the lower radial magnetic bearing 7 can be set near the center of gravity of the rotor to facilitate the control of the rotor, and because the radial magnetic bearing near the center of gravity of the rotor needs to output a greater force, it is necessary to increase the axial length of the lower radial magnetic bearing 7, that is, to increase the magnetic area between the stator core inside the lower radial magnetic bearing 7 and the bearing rotor 71 to obtain a greater magnetic force.

[0035] like Figure 5 As shown, the axial thrust magnetic suspension bearing 6 includes a first component 601, a second component 602 and a magnetic attraction thrust disk 603, the second component 602 is used to adjust the axial displacement, and the thrust disk 603 is used to attract the rotor to suspend. In this embodiment, the magnetic area of ​​the first component 601 and the thrust disk 603 is greater than the magnetic area of ​​the second component 602 and the thrust disk 603 (that is, the volume of the first component 601 is greater than the second component 602) to increase the axial magnetic force of the first component 601. It should be understood that when the conditions for rotor suspension control are met, the volume size of the components 601 and 602 of the axial thrust magnetic suspension bearing can be set according to actual needs.

[0036] In addition, the axial thrust magnetic suspension bearing 6 is installed on the same side as the upper protection bearing 27, and the axial distance between the axial thrust magnetic suspension bearing 6 and the upper protection bearing 27 should be less than or equal to twice the thickness of the upper radial magnetic bearing 5. The reasons are as follows:

[0037] Since the axial thrust magnetic suspension bearing 6 is located below the upper protection bearing 27 and is relatively closer to the impeller 15, when the molten salt pump is working, the temperature of the axial thrust magnetic suspension bearing 6 is higher than that of the upper protection bearing 27. According to the thermal expansion and contraction effect, if the axial distance between the axial thrust magnetic suspension bearing 6 and the upper protection bearing 27 is too far, when the gap between the axial thrust magnetic suspension bearing stator 62 and the axial thrust magnetic suspension bearing rotor 61 is small, the gap between the axial thrust magnetic suspension bearing 6 and the axial thrust magnetic suspension bearing rotor 61 after expansion will be smaller than the gap between the upper protection bearing 27 and the rotor, and at this time, the upper protection bearing 27 loses its protective function in the axial direction.

[0038] According to Maxwell's electromagnetic force formula:

[0039]

[0040] Among them, F is the electromagnetic force, B is the magnetic induction intensity, S is the magnetic pole area, and μ0 is the air magnetic permeability. Because:

[0041]

[0042] Where N is the number of coil turns, I is the current, and δ is the air gap. Therefore:

[0043]

[0044] It can be seen from the above formula that the electromagnetic attraction is proportional to the square of the current and inversely proportional to the square of the air gap. Therefore, the larger the air gap between the axial thrust magnetic bearing 6 and the axial thrust magnetic bearing rotor 61, the smaller the attraction. In order for the axial thrust magnetic bearing 6 to provide sufficient axial force to control the rotor, the air gap must be designed to be very small. Therefore, in order to avoid the upper protective bearing 27 losing its axial protection function due to thermal expansion and contraction, the present invention installs the axial thrust magnetic bearing 6 and the upper protective bearing 27 with axial protection function on the same side, and the axial distance is set to be less than or equal to twice the thickness of the upper radial magnetic bearing 5.

[0045] Before the high-temperature molten salt pump of the present invention is operated, the axial thrust magnetic suspension bearing 6 is energized to control the suspension of the rotating component 1. Then the upper and lower radial magnetic suspension bearings 5 ​​and 7 are energized to control the radial position of the rotating component 1. Finally, the shielded motor 8 is energized to control the rotation of the rotating component 1. While the rotating component 1 rotates, the position and vibration of the rotating component 1 are controlled by the magnetic suspension bearings 5, 6, and 7, and finally the high-temperature and high-pressure molten salt is pumped out at a specified speed. The entire magnetic suspension system includes rotors, radial magnetic suspension bearings, axial magnetic suspension bearings, sensors, power amplifiers and controllers, and its working principle is as follows: Figure 6 As shown: the sensor detects the offset of the rotor relative to the reference position, and the controller gives a control signal according to the offset. The control signal is converted into a control current after passing through a power amplifier. The corresponding radial magnetic bearing or axial magnetic bearing generates a corresponding electromagnetic field according to the change of the control current. The magnetic field force finally formed always maintains the rotor suspended at the set position.

[0046] The connecting cylinder 3 is used to connect the bearing cylinder 2 and the annular pump body 4. Figure 7 As shown, the connecting cylinder 3 is a cylindrical component with flanges at both ends. Specifically, the connecting cylinder 3 is welded by a third flange 31, a cylinder wall 32 and a fourth flange 33. The cylinder wall 32 is provided with vent holes 34 in layers, and the fourth flange 33 is provided with a molten salt discharge hole 35 and a molten salt connecting hole 36. When the molten salt pump is working, the molten salt liquid level submerges the fourth flange 33, and the highest liquid level is slightly higher than the molten salt connecting hole 36.

[0047] The shielding plug 9 is located inside the connecting cylinder 3 as a whole, and is in a gas environment when the molten salt pump is working, playing a role of heat shielding. The shielding plug 9 is welded by the fifth flange 91, the second outer shell 92, the second inner shell 93, the partition 94 and the shielding block 95, and the fifth flange 91, the second outer shell 92, the second inner shell 93, the partition 94 and the shielding block 95 are combined to form a number of different shielding chambers 96. Among them, the fifth flange 91 is fixed to the second flange 23 by bolts, and the shielding chamber 96 is filled with heat insulation material. In order to keep the pressure of the gas inside and outside the shielding chamber 96 consistent, a vent is opened at any position of the inner and outer shells 92 and 93 corresponding to the shielding chamber 96. The shielding block 95 located at the bottom of the shielding plug 9 is a solid with a certain thickness, and the material filled inside the solid can be selected according to the radiation dose. The shielding block 95 can also use an integral shielding block of different thicknesses, and the material of the integral shielding block is consistent with the main material of the shielding plug 9, which plays a role of radiation shielding.

[0048] like Figure 8 As shown, the annular pump body 4 includes a second cover plate 41, an annular shell 42, an inlet pipe 43 and an outlet pipe 44. The inner ring of the second cover plate 41 is provided with sealing teeth for forming a labyrinth seal to throttle the high-pressure molten salt. The lower surface of the second cover plate 41 is provided with radial guide vanes 45, and the radial guide vanes 45 are bolted to the inlet pipe 43. In addition, in order to eliminate pre-swirl, a guide spacer 46 is provided inside the inlet pipe 43. The above components together constitute the enveloping shell of the molten salt. The flow direction of the molten salt can be seen in FIG. Figure 5 As indicated by the arrow: the molten salt is sucked in through the inlet pipe 43, pressurized by the impeller 15, expanded by the radial guide vanes 45 and collected by the annular casing 42, and then pumped out from the outlet pipe 44.

[0049] The high-temperature shielded molten salt pump supported by the magnetic bearing of the present invention adopts a built-in shielded motor and a frictionless magnetic bearing that can reduce the axial size, and the seal of the entire pump is a non-dynamic seal, so it has the characteristics of compact structure, stable operation, convenient maintenance, and no wear, and can achieve the effect of completely isolating the atmosphere inside and outside the pump unit. The molten salt pump of the present invention can realize continuous operation under 800℃ molten salt medium, can be applied to molten salt drive in molten salt piles and molten salt energy storage devices, and the pumping medium is suitable for fluoride salts, chloride salts, nitrates, carbonates or multi-component molten salt media, and can also be applied to high-temperature liquid media such as heat transfer oil, and can also be applied to the transportation of high-temperature harmful liquid media.

[0050] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A high-temperature shielded molten salt pump supported by a magnetic bearing, comprising a rotating assembly having a main shaft, and a bearing cylinder, a connecting cylinder and an annular pump body arranged in sequence from top to bottom, wherein the main shaft passes through the connecting cylinder and extends to the inside of the bearing cylinder and the annular pump body, characterized in that: Also includes: a first cover plate, sealingly connected to the top of the bearing cylinder; A magnetic suspension bearing group is arranged inside the bearing cylinder, comprising an upper radial magnetic suspension bearing, an axial thrust magnetic suspension bearing and a lower radial magnetic suspension bearing; A shielded motor is provided between the axial thrust magnetic suspension bearing and the lower radial magnetic suspension bearing; A shielding plug is arranged inside the connecting cylinder; The axial thrust magnetic suspension bearing comprises a first component, a second component and a thrust plate, wherein the magnetic area of ​​the first component and the thrust plate is greater than the magnetic area of ​​the second component and the thrust plate; An upper protective bearing is provided above the upper radial magnetic suspension bearing, and a lower protective bearing is provided below the lower radial magnetic suspension bearing.

2. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 1 is characterized in that: The upper radial magnetic suspension bearing rotor, the axial thrust magnetic suspension bearing rotor, the shielded motor rotor and the lower radial magnetic suspension bearing rotor are sequentially installed in the middle and upper part of the main shaft from top to bottom, and an impeller is arranged at the lower part.

3. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 2 is characterized in that: A first sleeve and a second sleeve are provided on the upper side of the upper radial magnetic bearing rotor and between the upper radial magnetic bearing rotor and the axial thrust magnetic bearing rotor, and a third sleeve and a fourth sleeve are provided between the axial thrust magnetic bearing rotor and the shielded motor rotor and between the shielded motor rotor and the lower radial magnetic bearing rotor.

4. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 1 is characterized in that: The bearing cylinder is welded by a first outer shell, a first inner shell and a first flange, and a cooling channel is provided between the first outer shell and the first inner shell.

5. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 4 is characterized in that: The interior of the first inner shell is arranged with an upper radial magnetic bearing stator, an axial thrust magnetic bearing stator, a shielded motor stator and a lower radial magnetic bearing stator from top to bottom. The upper radial magnetic bearing stator and the axial thrust magnetic bearing stator are located in the first inner shell in sequence, and the lower radial magnetic bearing stator is installed in the first flange by bolts.

6. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 5, characterized in that: The shielding motor stator is sleeved with a shielding sleeve, the upper part of the shielding sleeve is connected to the lower end surface of the axial thrust magnetic suspension bearing stator, and the lower part is connected to the upper end surface of the lower radial magnetic suspension bearing stator.

7. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 1, characterized in that: The upper protection bearing and the upper radial magnetic bearing stator share a bearing housing, and the lower protection bearing and the lower radial magnetic bearing stator share a bearing housing.

8. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 1, characterized in that: An axial distance between the axial thrust magnetic suspension bearing and the upper protection bearing is less than or equal to twice the thickness of the upper radial magnetic suspension bearing.

9. The high-temperature shielded molten salt pump supported by a magnetic bearing according to claim 1, characterized in that: The shielding plug is welded by a fifth flange, a second outer shell, a second inner shell, a partition and a shielding block, and has a plurality of shielding chambers filled with heat insulation materials.

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