CN113202780A

CN113202780A - High-temperature shielding molten salt pump supported by magnetic suspension bearing

Info

Publication number: CN113202780A
Application number: CN202110641881.5A
Authority: CN
Inventors: 张健宇; 尹成科; 邹杨; 孔祥波; 李志军; 傅瑶; 樊辉青; 傅远; 戴志敏; 徐洪杰
Original assignee: Suzhou Suci Intelligent Technology Co ltd; Shanghai Institute of Applied Physics of CAS
Current assignee: Suzhou Suci Intelligent Technology Co ltd; Shanghai Institute of Applied Physics of CAS
Priority date: 2021-06-09
Filing date: 2021-06-09
Publication date: 2021-08-03

Abstract

The invention relates to a high-temperature shielding molten salt pump supported by a magnetic suspension bearing, which comprises a rotating assembly with a main shaft, a bearing cylinder, a connecting cylinder and an annular pump body, wherein the bearing cylinder, the connecting cylinder and the annular pump body are sequentially arranged from top to bottom, the main shaft penetrates through the connecting cylinder and extends to the interior of the bearing cylinder and the interior of the annular pump body, and the high-temperature shielding molten salt pump also comprises: the first cover plate is connected to the top of the bearing cylinder in a sealing mode; the magnetic suspension bearing group is arranged inside the bearing cylinder and comprises an upper radial magnetic suspension bearing, an axial thrust magnetic suspension bearing and a lower radial magnetic suspension bearing; the shielding motor is arranged between the axial thrust magnetic suspension bearing and the lower radial magnetic suspension bearing; and the shielding plug is arranged inside the connecting cylinder body. The molten salt pump has the advantages of compact integral structure, stable operation, realization of complete isolation of internal and external atmosphere environments, convenient maintenance and high efficiency.

Description

High-temperature shielding molten salt pump supported by magnetic suspension bearing

Technical Field

The invention relates to the field of molten salt pumps, in particular to a high-temperature shielding molten salt pump supported by a magnetic suspension bearing.

Background

The high-temperature molten salt pump is a heat transfer medium driving device in a molten salt pile or a molten salt heat storage project, is used for overcoming system resistance of a loop, and is a heart of a loop system. At present, a high-temperature molten salt pump commonly used in a molten salt pile or a molten salt heat storage project is a vertical submerged pump driven by an independent motor. However, such molten salt pumps have a number of disadvantages: firstly, it adopts the shaft coupling to link to each other with independent motor for overall structure is longer. Secondly, the independent motor and the pump body are provided with respective bearings, so that more noise is generated, vibration is larger, and operation is unstable. Moreover, the bearings need auxiliary measures such as oil cooling, and the maintenance of the whole structure is complicated due to more bearings. Thirdly, the sealing performance is poor, the atmosphere inside and outside the pump body cannot be completely isolated, and meanwhile, an additional dynamic sealing structure is required to be added for sealing.

Therefore, in order to meet the requirement of safe and reliable transportation of the molten salt medium, a molten salt pump which has a compact structure, is stable and reliable in operation, is convenient to maintain and has good isolation performance of internal and external atmospheres needs to be developed.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a high-temperature shielding molten salt pump supported by a magnetic suspension bearing, which meets the requirements of compact structure, stable and reliable operation, convenient maintenance and good isolation performance of internal and external atmospheres.

The invention provides a high-temperature shielding molten salt pump supported by a magnetic suspension bearing, which comprises a rotating assembly with a main shaft, a bearing cylinder, a connecting cylinder and an annular pump body, wherein the bearing cylinder, the connecting cylinder and the annular pump body are sequentially arranged from top to bottom, the main shaft penetrates through the connecting cylinder and extends into the bearing cylinder and the annular pump body, and the high-temperature shielding molten salt pump further comprises: the first cover plate is connected to the top of the bearing cylinder in a sealing mode; the magnetic suspension bearing group is arranged inside the bearing cylinder and comprises an upper radial magnetic suspension bearing, an axial thrust magnetic suspension bearing and a lower radial magnetic suspension bearing; the shielding motor is arranged between the axial thrust magnetic suspension bearing and the lower radial magnetic suspension bearing; and the shielding plug is arranged inside the connecting cylinder body.

Furthermore, an upper radial magnetic suspension bearing rotor, an axial thrust magnetic suspension bearing rotor, a shield motor rotor and a lower radial magnetic suspension bearing rotor are sequentially arranged on the middle upper part of the main shaft from top to bottom, and an impeller is arranged on the lower part of the main shaft.

Furthermore, a first shaft sleeve and a second shaft sleeve are arranged on the upper side of the upper radial magnetic suspension bearing rotor and between the upper radial magnetic suspension bearing rotor and the axial thrust magnetic suspension bearing rotor, and a third shaft sleeve and a fourth shaft sleeve are arranged between the axial thrust magnetic suspension bearing rotor and the shield motor rotor and between the shield motor rotor and the lower radial magnetic suspension bearing rotor.

Further, the bearing cylinder is formed by welding a first outer shell, a first inner shell and a first flange, and a cooling flow channel is arranged between the first outer shell and the first inner shell.

Furthermore, an upper radial magnetic suspension bearing stator, an axial thrust magnetic suspension bearing stator, a shielding motor stator and a lower radial magnetic suspension bearing stator are sequentially arranged in the first inner shell from top to bottom, the upper radial magnetic suspension bearing stator and the axial thrust magnetic suspension bearing stator are sequentially located in the first inner shell, and the lower radial magnetic suspension bearing stator is installed in the first flange through bolts.

Furthermore, a shielding sleeve is sleeved on the stator of the shielding motor, the upper part of the shielding sleeve is connected with the lower end face of the axial thrust magnetic suspension bearing stator, and the lower part of the shielding sleeve is connected with the upper end face of the lower radial magnetic suspension bearing stator.

Further, the axial thrust magnetic suspension bearing comprises a first assembly, a second assembly and a thrust disc, and the magnetic force area between the first assembly and the thrust disc is larger than that between the second assembly and the thrust disc.

Furthermore, an upper protection bearing is arranged above the upper radial magnetic suspension bearing, and a lower protection bearing is arranged below the lower radial magnetic suspension bearing.

Further, the upper protection bearing and the upper radial magnetic suspension bearing stator share a bearing shell, and the lower protection bearing and the lower radial magnetic suspension bearing stator share a bearing shell.

Further, the axial distance between the axial thrust magnetic suspension bearing and the upper protection bearing is less than or equal to two times of the thickness of the upper radial magnetic bearing.

Furthermore, the shielding plug is formed by welding a fifth flange, a second outer shell, a second inner shell, a partition plate and a shielding block and is provided with a plurality of shielding cavities, and heat insulation materials are filled in the shielding cavities.

The invention adopts the built-in shielding motor capable of reducing the axial size and the friction-free magnetic suspension bearing, so that the molten salt pump has compact integral structure and stable operation. The high-temperature shielding molten salt pump supported by the magnetic suspension bearing adopts static seal, and can realize the effect of completely isolating the internal and external atmosphere environments. In addition, the magnetic suspension bearing is convenient to disassemble, so that the maintenance is convenient and efficient.

Drawings

FIG. 1 is a schematic diagram of a magnetically levitated bearing supported high temperature shielded molten salt pump according to the present invention.

Fig. 2 is a schematic structural view of the rotating assembly of fig. 1.

Fig. 3 is a schematic view of the structure of the bearing cartridge of fig. 1.

Fig. 4 is a schematic structural diagram of the radial magnetic bearing in fig. 1.

Fig. 5 is a schematic structural view of the axial thrust magnetic bearing in fig. 1.

Fig. 6 is a schematic diagram of the operation of a magnetic levitation system.

Fig. 7 is a schematic view of the structure of the connection cylinder of fig. 1.

Fig. 8 is a schematic view of the ring pump body of fig. 1.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the high-temperature shielding molten salt pump supported by the magnetic suspension bearing according to a preferred embodiment of the present invention includes a rotating assembly 1, and a bearing cylinder 2, a connecting cylinder 3, and an annular pump body 4, which are sequentially arranged from top to bottom, wherein the rotating assembly 1 penetrates through the connecting cylinder 3 and extends to the inside of the bearing cylinder 2 and the annular pump body 4. The bearing cylinder 2 is provided with a first cover plate 211, the first cover plate 211 is fixed on the top of the bearing cylinder 2 through bolts, and the first cover plate 211 and the bearing cylinder 2 are sealed through a sealing washer 212 (shown in fig. 3). Thus, the first cover plate 211 and the bearing cylinder 2 form two boundaries for isolating the inside and outside atmospheres of the molten salt pump. And the inside of the bearing cylinder 2 is provided with a magnetic suspension bearing group comprising an upper radial magnetic suspension bearing 5, an axial thrust magnetic suspension bearing 6 and a lower radial magnetic suspension bearing 7 and a shielding motor 8, and a shielding plug 9 is arranged in the connecting cylinder 3.

As shown in fig. 2, the rotating assembly 1 includes a main shaft 11, and a middle upper portion of the main shaft 11 extends to the inside of the bearing cylinder 2, and a lower portion thereof 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 shield motor rotor 81 and the lower radial magnetic suspension bearing rotor 71 are sequentially mounted on the middle upper portion of the main shaft 11 from top to bottom, a first locking nut 111 is arranged on the uppermost side of the main shaft 11, and a bearing gland 110 of the upper protection bearing 27 and a bearing lower cover 12 of the upper protection bearing 27 are sequentially arranged below the first locking nut 111 (the upper protection bearing 27 is shown in fig. 3). A first shaft sleeve 13 is arranged between the upper radial magnetic suspension bearing rotor 51 and the axial thrust magnetic suspension bearing rotor 61, a second shaft sleeve 14 is arranged between the axial thrust magnetic suspension bearing rotor 61 and the shield motor rotor 81, and a third shaft sleeve 15 is arranged between the shield motor rotor 81 and the lower radial magnetic suspension bearing rotor 71. The first sleeve 13, the second sleeve 14 and the third sleeve 15 are used to support the

rotors

51, 61, 71, 81, which are assembled on the main shaft 11 by interference fit, and finally locked by the first lock nut 111 at the top end of the main shaft 11. The lower part of the main shaft 11 is provided with an impeller 16, and the impeller 16 is locked on the main shaft 11 by a second lock nut 17. The impeller 16 is provided with a key 18 for transmitting torque. The back of the impeller 16 is provided with a fourth shaft sleeve 19 for labyrinth throttling sealing of molten salt on the back.

The bearing cylinder 2 provides a mounting position for the magnetic bearing group and the shielding motor 8 and cools them. As shown in fig. 3, the bearing cylinder 2 is formed by welding a first outer housing 21, a first inner housing 22, and a first flange 23. A cooling flow channel is arranged between the first outer shell 21 and the first inner shell 22, and a cooling medium with external circulation flows into the cooling flow channel through the water inlet 242 and flows out through the water outlet 241 to take away heat generated during the operation of each bearing and the shielding motor 8 and heat transferred from lower components, so as to ensure that each bearing and the shielding motor 8 can work at a proper temperature. In order to supply power to each device (bearing, motor, sensor, etc.) in the bearing cylinder 2, a terminal box 25 is provided on the upper portion of the first outer housing 21, and wiring grooves 26 are symmetrically arranged in the circumferential direction inside the first inner housing 22. The electric cables of each device in the bearing cylinder 2 are arranged in the wiring groove 26 and pass through the through hole at the upper part of the bearing cylinder 2 to be connected into the junction box 25. A gasket is further provided on the electrical connector mounting panel 251 inside the junction box 25 for isolating the atmosphere inside and outside the bearing cylinder 2.

An upper radial magnetic suspension bearing stator 52, an axial thrust magnetic suspension bearing stator 62, a shielding motor stator 82 and a lower radial magnetic suspension bearing stator 72 are sequentially arranged in the first inner housing 22 from top to bottom, the upper radial magnetic suspension bearing stator 52 is separated from the axial thrust magnetic suspension bearing stator 62 through a retainer ring 213, a step-shaped sinking platform is arranged on the inner wall of the first inner housing 22, so that the inner diameters of the upper side and the lower side of the first inner housing 22 on the sinking platform are different, and the axial thrust magnetic suspension bearing stator 62 is arranged on the supporting surface of the sinking platform in the first inner housing 22. In addition, in order to prevent the molten salt steam from corroding the electronic coils of the shield motor 8, the shield motor stator 82 is sleeved with a shield sleeve 83, the upper part of the shield sleeve 83 is connected with the lower end face of the axial thrust magnetic suspension bearing stator 62, and the lower part of the shield sleeve 83 is connected with the upper end face of the lower radial magnetic suspension bearing stator 72.

The positions of the

stators

52, 62, 72, 82 correspond to the positions of the

rotors

51, 61, 71, 81 mounted on the main shaft 11 one by one, and a gap is formed between the corresponding stators and rotors, so that the upper radial magnetic suspension bearing 5, the axial thrust magnetic suspension bearing 6, the lower radial magnetic suspension bearing 7 and the shield motor 8 are respectively formed. Wherein, the upper radial magnetic suspension bearing 5 and the lower radial magnetic suspension bearing 7 provide radial force support for the rotating assembly 1, the axial thrust magnetic suspension bearing 6 provides axial positioning for the rotating assembly 1 to prevent the rotating assembly 1 from axially moving, and the shield motor 8 provides power for the rotation of each rotor.

In the present embodiment, an upper protection bearing 27 is disposed above the upper radial magnetic suspension bearing 5, a lower protection bearing 28 is disposed below the lower radial magnetic suspension bearing 7, the upper protection bearing 27 and the upper radial magnetic suspension bearing stator 52 share a bearing housing, and the lower protection bearing 28 and the lower radial magnetic suspension bearing stator 72 share a bearing housing. The upper protection bearing 27 is placed on the upper protection bearing housing 271 and fixed by the upper protection bearing cover 272, and the upper protection bearing housing 271 is fixed inside the first inner case 22 by spring compression through the end locking ring 273. It should be noted that the upper protective bearing seat 272 also serves as a stator housing of the upper radial magnetic bearing 5. The lower protection bearing 28 is placed on the second flange 281, and the second flange 281 is a combined flange, and is connected to the first flange 23 through bolts, and is used for supporting and positioning the lower radial magnetic suspension bearing 7, and serving as a bearing seat of the lower protection bearing 28, and simultaneously serving as a stator shell of the lower radial magnetic suspension bearing 7, so that the lower protection bearing 28 is convenient to detach and maintain. The

protective bearings

27, 28 play a role in supporting the shafting and protecting the impact during power failure, and are not in contact with the

magnetic bearings

5, 6, 7 during the operation of the molten salt pump. Since the upper protection bearing 27 is provided, correspondingly, a bearing cover 110 (see fig. 2) is provided at an end of the main shaft 11, and the bearing cover 110 is locked by the first lock nut 111 to receive the axial force by the protection bearing 27. Further, a purge gas pipe 29 is provided outside the upper end portion of the bearing cylinder 2, and the purge gas pipe 29 purges downward along the clearance of the fixed rotor member.

As can be seen from fig. 1 to 3, the magnetic suspension bearing set and the shield motor 8 are disposed at a position far away from the impeller 16, and this arrangement can reduce the operating temperature of each magnetic suspension bearing and the shield motor 8, and avoid the molten salt pump from being affected by high-temperature media to fail. And, the distance between the upper radial magnetic suspension bearing 5 and the impeller 16 is longest, so that when the rotor of the impeller 16 is controlled to be balanced, the force applied to the rotor of the impeller 16 by the upper radial magnetic suspension bearing 5 is smaller, the required current is smaller, and the cost is saved. It should be noted that in other embodiments, the positions of the upper radial magnetic suspension bearing 5 and the axial thrust magnetic suspension bearing 6 can be interchanged as required.

As shown in fig. 4, in order to reduce eddy currents as much as possible, the stator cores of the radial

magnetic bearing stators

52 and 72 and the rotor portions (i.e., the radial magnetic bearing rotors 51 and 71) opposite to the cores are laminated, and the layers are insulated from each other. The invention uses an 8-pole radial magnetic bearing so that every two pole pairs can be designed according to the cartesian coordinate system commonly used in mechanics to simplify bearing control, the polarity on the plane perpendicular to the rotor rotation axis being the NSSNNSSN sequence or nsnsnsnsnsnsns sequence.

It should be noted that the axial length of the upper radial magnetic suspension bearing 5 in the present invention may be smaller than, equal to or larger than the lower radial magnetic suspension bearing 7. In the present embodiment, the axial length of the upper radial magnetic bearing 5 is smaller than the axial length of the lower radial magnetic bearing 7. Since the mounting position of the lower radial magnetic suspension bearing 7 can be set near the center of gravity of the rotor to facilitate the control of the rotor, and since the radial magnetic bearings near the center of gravity of the rotor need to output larger force, the axial length of the lower radial magnetic suspension bearing 7 needs to be increased, that is, the magnetic force area between the stator core inside the lower radial magnetic suspension bearing 7 and the bearing rotor 71 needs to be increased to obtain larger magnetic force.

As shown in fig. 5, the magnetic thrust bearing 6 includes a first assembly 601 and a second assembly 602, and a magnetically attractive thrust disc 603, wherein the second assembly 602 is used for adjusting axial displacement, and the thrust disc 603 is used for attracting the rotor to float. In this embodiment, the magnetic area of the first component 601 and the thrust disc 603 is larger than that of the second component 602 and the thrust disc 603 (i.e. the volume of the first component 601 is larger than that of the second component 602), so as to increase the axial magnetic force of the first component 601. It should be understood that the

components

601, 602 of the axial thrust magnetic suspension bearing can be set according to actual requirements when the conditions for rotor levitation control are met.

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 from the upper protection bearing 27 should be less than or equal to twice the thickness of the upper radial magnetic bearing 5. The reason is as follows:

because the axial thrust magnetic suspension bearing 6 is positioned below the upper protective bearing 27 and is relatively closer to the impeller 15, the temperature of the axial thrust magnetic suspension bearing 6 is higher than that of the upper protective bearing 27 when the molten salt pump works. According to the thermal expansion and cold 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 expanded axial thrust magnetic suspension bearing 6 and the axial thrust magnetic suspension bearing rotor 61 is smaller than the gap between the upper protection bearing 27 and the rotor, and at this time, the upper protection bearing 27 loses the protection effect in the axial direction.

According to the maxwell electromagnetic attraction formula:

wherein F is electromagnetic force, B is magnetic induction intensity, S is magnetic pole area, mu₀Is the air permeability. Because:

where N is the number of coil turns, I is the current, and δ is the air gap. Thus:

as can be seen from the above equation, the electromagnetic attraction is proportional to the current squared and inversely proportional to the air gap squared. Therefore, the larger the air gap between the magnetic thrust bearing 6 and the magnetic thrust bearing rotor 61, the smaller the suction force. In order for the axial thrust magnetic bearing 6 to provide sufficient axial force control of the rotor, the air gap must be designed to be small. Therefore, in order to avoid the effect of expansion with heat and contraction with cold to make the upper protective bearing 27 lose the axial protection function, the invention installs the axial thrust magnetic suspension bearing 6 and the upper protective bearing 27 with the 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.

Before the high-temperature molten salt pump operates, the axial thrust magnetic suspension bearing 6 is electrified to control the rotating assembly 1 to suspend. And electrifying the upper and lower radial

magnetic suspension bearings

5 and 7 to control the radial position of the rotating assembly 1. Finally, the shielding motor 8 is electrified to control the rotating assembly 1 to rotate. While the rotor assembly 1 rotates, the

magnetic bearings

5, 6, and 7 control the position and vibration of the rotor assembly 1, and finally the molten salt is pumped at a predetermined rotational speed and high temperature and high pressure. The whole magnetic suspension system comprises each rotor, a radial magnetic suspension bearing, an axial magnetic suspension bearing, a sensor, a power amplifier and a controller, and the working principle is as shown in figure 6: the sensor detects the offset of the rotor relative to the reference position, the controller gives out a control signal according to the offset, the control signal is converted into control current after passing through the power amplifier, the corresponding radial magnetic bearing or axial magnetic bearing generates a corresponding electromagnetic field according to the change of the control current, and finally the formed magnetic field force always keeps the rotor suspended at the set position.

The connection cylinder 3 is used to connect the bearing cylinder 2 and the annular pump body 4, and as shown in fig. 7, the connection cylinder 3 is a cylindrical member having flanges at both ends. Specifically, the connection cylinder 3 is formed by welding a third flange 31, a cylinder wall 32, and a fourth flange 33. The barrel wall 32 is provided with vent holes 34 in a layered manner, and the fourth flange 33 is provided with a molten salt discharge hole 35 and a molten salt communication hole 36. When the molten salt pump works, the molten salt liquid level submerges the fourth flange 33, and the highest liquid level is slightly higher than the molten salt communicating hole 36.

The shielding plug 9 is integrally positioned in the connecting cylinder 3, is positioned in a gas environment when the molten salt pump works, and plays a role of heat shielding. The shielding plug 9 is formed by welding a fifth flange 91, a second outer shell 92, a second inner shell 93, a partition 94 and a 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 plurality of different shielding cavities 96. The fifth flange 91 is fixed to the second flange 23 by bolts, and the shield cavity 96 is filled with a heat insulating material. In order to keep the pressure of the gas inside and outside the shield chamber 96 uniform, vent holes are opened in the inner and

outer cases

92 and 93 at positions corresponding to the shield chamber 96. The shielding block 95 located at the lower part of the shielding plug 9 is a solid body with a certain thickness, and the material filled inside the solid body can be selected according to the radiation dose. The shielding block 95 may also be an integral shielding block of different thickness, the material of the integral shielding block is the same as the main material of the shielding plug 9, and the radiation shielding effect is achieved.

As shown in fig. 8, the annular pump body 4 includes a second cover plate 41, an annular housing 42, an inlet pipe 43, and an outlet pipe 44. And the inner ring of the second cover plate 41 is provided with sealing teeth for forming labyrinth seal and throttling high-pressure molten salt. The lower surface of the second cover plate 41 is provided with a radial guide vane 45, and the radial guide vane 45 is connected with the inlet pipe 43 through a bolt. In addition, to eliminate pre-swirl, the inlet tube 43 is internally provided with a flow guide septum 46. These components together form a surrounding shell of molten salt, the flow direction of which can be seen as indicated by the arrows in fig. 5: molten salt is drawn in through inlet pipe 43, pressurized by impeller 15, diffused by radial vanes 45 and collected by annular housing 42, and pumped out through outlet pipe 44.

The high-temperature shielding molten salt pump supported by the magnetic suspension bearing adopts the built-in shielding motor capable of reducing the axial size and the frictionless magnetic suspension bearing, and the whole pump is sealed without dynamic seal, so that the high-temperature shielding molten salt pump has the characteristics of compact structure, stable operation, convenient maintenance and no abrasion, and can realize the effect of completely isolating the internal and external atmosphere environments of the pump unit. The molten salt pump can realize continuous operation under a molten salt medium at 800 ℃, can be applied to molten salt driving in a molten salt pile and a molten salt energy storage device, and the pumping medium is suitable for a fluorine salt, a chlorine salt, a nitrate, a carbonate or a multi-element molten salt medium, can also be applied to a high-temperature liquid medium such as heat conduction oil, and can also be applied to the transportation of a high-temperature harmful liquid medium.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.

Claims

1. The utility model provides a high temperature shielding molten salt pump that magnetic suspension bearing supported, includes the rotating assembly who has the main shaft and the bearing barrel that top-down arranged in proper order, connects barrel and the annular pump body, the main shaft runs through connect the barrel and extend to the bearing barrel with the inside of the annular pump body, its characterized in that still includes:

the first cover plate is connected to the top of the bearing cylinder in a sealing mode;

the magnetic suspension bearing group is arranged inside the bearing cylinder and comprises an upper radial magnetic suspension bearing, an axial thrust magnetic suspension bearing and a lower radial magnetic suspension bearing;

the shielding motor is arranged between the axial thrust magnetic suspension bearing and the lower radial magnetic suspension bearing;

and the shielding plug is arranged inside the connecting cylinder body.

2. The high-temperature shielding molten salt pump supported by the magnetic suspension bearing as claimed in claim 1, wherein the upper radial magnetic suspension bearing rotor, the axial thrust magnetic suspension bearing rotor, the shielding motor rotor and the lower radial magnetic suspension bearing rotor are sequentially installed on the middle upper part of the main shaft from top to bottom, and the lower part of the main shaft is provided with an impeller.

3. The magnetically levitated bearing supported high temperature shielded molten salt pump of claim 2, wherein a first bushing and a second bushing are disposed on the upper side of said upper radial magnetically levitated bearing rotor and between said upper radial magnetically levitated bearing rotor and said axial thrust magnetically levitated bearing rotor, and a third bushing and a fourth bushing are disposed between said axial thrust magnetically levitated bearing rotor and said shield motor rotor and between said shield motor rotor and said lower radial magnetically levitated bearing rotor.

4. The magnetically suspended bearing supported high temperature shielding molten salt pump as set forth in claim 1, wherein the bearing cylinder is welded by a first outer housing, a first inner housing and a first flange, and a cooling flow passage is provided between the first outer housing and the first inner housing.

5. The high-temperature shielding molten salt pump supported by the magnetic suspension bearing as claimed in claim 4, wherein an upper radial magnetic suspension bearing stator, an axial thrust magnetic suspension bearing stator, a shielding motor stator and a lower radial magnetic suspension bearing stator are sequentially arranged in the first inner housing from top to bottom, the upper radial magnetic suspension bearing stator and the axial thrust magnetic suspension bearing stator are sequentially located in the first inner housing, and the lower radial magnetic suspension bearing stator is mounted in the first flange through bolts.

6. The high-temperature shielding molten salt pump supported by the magnetic suspension bearing as claimed in claim 5, wherein the shielding motor stator is sleeved with a shielding sleeve, the upper part of the shielding sleeve is connected with the lower end face of the axial thrust magnetic suspension bearing stator, and the lower part of the shielding sleeve is connected with the upper end face of the lower radial magnetic suspension bearing stator.

7. The magnetically levitated bearing supported high temperature shield molten salt pump of claim 1, wherein the axial thrust magnetically levitated bearing includes a first assembly, a second assembly, and a thrust disc, a magnetic force area of the first assembly and the thrust disc is greater than a magnetic force area of the second assembly and the thrust disc.

8. The magnetically levitated bearing supported high temperature shielding molten salt pump of claim 5, wherein an upper protection bearing is disposed above said upper radial magnetic levitation bearing, and a lower protection bearing is disposed below said lower radial magnetic levitation bearing.

9. The magnetically levitated bearing supported high temperature shield molten salt pump of claim 8, wherein said upper protective bearing shares a bearing housing with said upper radial magnetically levitated bearing stator and said lower protective bearing shares a bearing housing with said lower radial magnetically levitated bearing stator.

10. The magnetically levitated bearing supported high temperature shielded molten salt pump of claim 8, wherein an axial distance of said axial thrust magnetic bearing from said upper protective bearing is less than or equal to two times a thickness of said upper radial magnetic bearing.

11. The high-temperature shielding molten salt pump supported by the magnetic bearing as claimed in claim 1, wherein the shielding plug is formed by welding a fifth flange, a second outer shell, a second inner shell, a partition plate and a shielding block, and has a plurality of shielding chambers filled with heat insulating materials.