Closed supercooling liquid nitrogen circulating device suitable for superconducting shunt reactor

Abstract

The invention discloses a closed supercooling liquid nitrogen circulating device suitable for a superconducting shunt reactor, which relates to a liquid nitrogen cooling technology and comprises a Dewar assembly, a circulating assembly and a refrigerating assembly, the circulation assembly comprises a circulation pipe, and a liquid outlet valve, a pump front pressure gauge, a liquid nitrogen pump, a pump rear pressure gauge, a relief valve, an electric control valve, a liquid nitrogen valve, a temperature sensor and a valve rear pressure gauge are sequentially installed on the side, close to the liquid outlet end of the Dewar assembly, of the circulation pipe in the liquid nitrogen flowing direction; the refrigeration assembly comprises a Stirling cryocooler and a water cooling unit used for conducting heat dissipation on the Stirling cryocooler. According to the invention, a plurality of pressure gauges and valves are distributed on the circulating pipe, the temperature and pressure of each key measuring point of the superconducting magnet and the refrigerating system are monitored in real time, the operation state of the monitoring system is known, then automatic control operation is realized, and the working stability and reliability of the superconducting magnet are effectively improved.

Description

Technical Field

[0001] The invention relates to liquid nitrogen cooling equipment, in particular to a closed supercooled liquid nitrogen circulation device suitable for a superconducting shunt reactor. Background Art

[0002] Liquid nitrogen has low preparation cost and stable chemical and insulating properties. It is a reliable cooling medium for cooling high-temperature superconducting power devices. Therefore, all countries now use liquid nitrogen as a refrigerant.

[0003] Liquid nitrogen refrigeration methods are divided into open refrigeration and closed refrigeration. Compared with open refrigeration, the main advantage of closed refrigeration is lower operating costs, and it can also avoid the use of relatively large liquid nitrogen storage tanks for daily liquid nitrogen refilling. However, for closed liquid nitrogen refrigeration systems, since they do not need to be connected to an external cold source and the refrigeration is completed by internal refrigeration components, it is particularly important to ensure that they operate stably under the designed conditions and that the temperature is as uniform as possible. Furthermore, for this type of system, since the positions of the liquid inlet and outlet pipes inside the dewar tank are fixed, during the long-term circulation of supercooled liquid nitrogen, it is easy for a large area of ​​liquid nitrogen to stagnate in the dewar tank, affecting the heat exchange performance. Therefore, it is necessary to propose improvements. Summary of the invention

[0004] The object of the present invention is to provide a closed subcooled liquid nitrogen circulation device suitable for a superconducting shunt reactor, so as to solve the problem of how to ensure the stable operation of the cooling device under the designed working conditions in the prior art proposed in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A closed supercooled liquid nitrogen circulation device suitable for a superconducting shunt reactor comprises a Dewar assembly for containing liquid nitrogen, a circulation assembly for driving the circulation of liquid nitrogen, and a refrigeration assembly for refrigerating the liquid nitrogen, wherein the Dewar assembly comprises a Dewar tank, and the reactor is arranged in the Dewar tank; The circulation assembly includes a circulation pipe for connecting the Dewar assembly and the refrigeration assembly, one end of the circulation pipe is connected to the liquid outlet pipe of the Dewar assembly, and the other end of the circulation pipe is connected to the liquid inlet pipe of the Dewar assembly; A liquid outlet valve, a pressure gauge before the pump, a liquid nitrogen pump, a pressure gauge after the pump, a relief valve, an electric regulating valve, a liquid nitrogen valve, a temperature sensor and a pressure gauge after the valve are sequentially installed on one side of the circulation pipe close to the liquid outlet pipe of the Dewar assembly along the liquid nitrogen flow direction; a liquid inlet valve is fixedly installed on one side of the circulation pipe close to the liquid inlet pipe of the Dewar assembly; the refrigeration assembly includes a Stirling refrigerator and a water cooling unit for dissipating heat from the Stirling refrigerator.

[0006] As a further solution of the present invention: the Dewar assembly includes a thermal insulation box, a supporting platform is fixedly installed on the bottom of the inner wall of the thermal insulation box, a Dewar tank is placed on the supporting platform, a cover is fixedly installed on the top of the thermal insulation box, an airtight ring sleeve is fixedly connected to the edge of the cover, and a hanging ring is fixedly connected to the top of the cover.

[0007] As a further solution of the present invention: the top edge of the cover is rotatably connected with a plurality of locking bolts, the top edge of the heat insulation box is provided with a plurality of bolt holes, and the bottoms of the plurality of locking bolts are respectively threadedly connected with the plurality of bolt holes.

[0008] As a further solution of the present invention: a diverter assembly is fixedly installed on the top of the Dewar tank, and the diverter assembly includes a diverter cover plate, a center tube is fixedly connected to the top of the diverter cover plate, a mounting collar is rotatably connected to the middle of the center tube, a lower docking gear is fixedly connected to the bottom of the mounting collar, an upper docking gear is fixedly connected to the top of the mounting collar, a mounting frame is fixedly connected to the top of the mounting collar, a drive motor is fixedly connected to one side of the mounting frame, a drive gear is fixedly connected to the output end of the drive motor, and the drive gear is meshed with the upper docking gear; a plurality of diverter pipes are fixedly connected to the bottom of the center tube, a plurality of diverter regulating valves are fixedly connected to the middle of the plurality of diverter regulating valves, a plurality of regulating gears are fixedly connected to the regulating ends of the plurality of diverter regulating valves, and a plurality of regulating gears are meshed with the lower docking gear.

[0009] As a further solution of the present invention: the middle part of the liquid inlet pipe is bent in an arc shape, one end of the liquid inlet pipe close to the circulation pipe is horizontally arranged and fixedly connected to the circulation pipe, and the bottom of the liquid inlet pipe is vertically arranged and fixedly connected to the top of the central pipe.

[0010] As a further solution of the present invention: a dehumidification component is fixedly installed on one side of the heat insulation box, and the dehumidification component includes a shell, the top of the shell is fixedly connected with an air inlet hood, one side of the shell is fixedly connected with an air outlet hood, the bottom of the air inlet hood is fixedly connected with an air inlet pipe, the bottom of the air inlet pipe is fixedly connected with an air inlet pump, the output end of the air inlet pump is fixedly connected with the air outlet pipe, one end of the air outlet pipe is fixedly connected to the air outlet hood, and a dewatering filter is fixedly installed in the middle of the air outlet pipe.

[0011] As a further solution of the present invention: a reversing valve is fixedly installed in the middle of the air inlet pipe, one end of the reversing valve is fixedly connected to an exhaust pipe, and one end of the exhaust pipe is connected to the inside of the heat insulation box.

[0012] As a further solution of the present invention: the outer wall of the circulation pipe is covered with a heat insulation pad, and the outer wall of the heat insulation pad is fixedly connected with an outer protective sleeve.

[0013] As a further solution of the present invention: the working method of the closed subcooled liquid nitrogen circulation device comprises the following steps: Step 1: Check the Dewar assembly for leaks, conduct a 0.05MPa airtightness test on the Dewar tank and maintain the pressure for 20 minutes; then perform vacuum replacement, use a vacuum pump to evacuate to 0.1Pa, maintain the pressure for 30 minutes, and then fill with nitrogen to 0.02MPa, maintain the pressure for 30 minutes, and repeat this 3 times; finally, add liquid nitrogen; Step 2: Leakage detection of the circulation pipe. After the circulation assembly, the Dewar assembly and the refrigeration assembly are connected, the liquid outlet valve is opened and the circulation pipe and the entire circulation assembly are leak-checked by the flow of liquid nitrogen. Step 3: Precool the circulation pipe. Open the electric regulating valve, the relief valve and the branch low-temperature solenoid valve inside the Stirling refrigerator in turn, and then gradually open the liquid outlet valve. At this time, liquid nitrogen will flow into the circulation pipe through the valve; precool until the temperature sensor shows a temperature of -196°C, indicating that the circulation pipe has been precooled; Step 4: Run the refrigeration, first turn on the water cooling unit, then gradually open the relief valve, observe the status of the relief valve outlet, if all the liquid nitrogen is sprayed out in a columnar shape, you can turn on the liquid nitrogen pump, wait for the liquid nitrogen pump to run stably, and then turn on the Stirling refrigerator.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the liquid nitrogen in the dewar tank of the present invention flows into the circulation pipe through the liquid outlet valve, and the circulation power is provided by the liquid nitrogen pump, and is shunted into the liquefaction chamber of the Stirling refrigerator through the circulation pipe. The liquid nitrogen reaches a supercooled state after being cooled in the liquefaction chamber, and then flows into the interior of the dewar tank from the liquid inlet valve through the circulation pipe, so as to form a cycle, thereby achieving the purpose of supercooling the liquid nitrogen inside the dewar tank; by distributing a plurality of pressure gauges and valves on the circulation pipe, the temperature and pressure of each key measuring point of the superconducting magnet and the refrigeration system are monitored in real time, the operating state of the monitoring system is understood, and then the automatic control operation is realized, and the working stability and reliability of the supermagnet are effectively improved; The present invention provides a plurality of shunt pipes to deliver liquid nitrogen through different positions, and cooperates with a regulating valve to adjust the delivery flow of each shunt pipe, thereby changing the delivery amount of liquid nitrogen from different shunt pipes, so that the liquid nitrogen inside the dewar tank can flow slowly under the impetus of the liquid nitrogen delivered from different positions, thereby avoiding the formation of a dead zone; avoiding the problem of a liquid nitrogen dead zone inside the dewar tank caused by delivering liquid nitrogen from a single position; The present invention sets a dehumidification component, uses an air intake pump to draw in external air, and uses a dehumidification filter to filter and remove water vapor in the air, thereby reducing the moisture content of the ambient air in the working area and effectively avoiding condensation of water vapor on pipeline equipment; the connection direction of the air inlet pipe is changed by a reversing valve, and the air inside the insulation box is drawn out by an exhaust pipe, thereby achieving the removal of water vapor inside the insulation box. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the device layout of the present invention; Figure 2 A perspective view of a Dewar assembly of the present invention; Figure 3 This is a schematic diagram of the installation state of the Dewar tank of the present invention; Figure 4 is a cross-sectional view of the flow diversion component of the present invention; Figure 5 is a cross-sectional view of the dehumidification component of the present invention; Figure 6 It is a cross-sectional view of the circulation pipe of the present invention.

[0016] In the figure: 1. Dewar assembly; 101. Insulated box; 102. Liquid inlet pipe; 103. Liquid outlet pipe; 104. Cover; 105. Airtight ring; 106. Bolt hole; 107. Lifting ring; 108. Support platform; 2. Stirling refrigerator; 3. Water cooling unit; 4. Circulation assembly; 41. Liquid outlet valve; 42-1. Pressure gauge before pump; 42-2. Pressure gauge after pump; 42-3. Pressure gauge after valve; 43. Liquid nitrogen pump; 44. Release valve; 45. Electric regulating valve; 46. Liquid nitrogen valve; 47. Temperature sensor; 48. Liquid inlet valve; 401. Circulation pipe; 402. Insulated box Heat pad; 403, outer protective cover; 5, Dewar tank; 6, diversion assembly; 601, diversion cover plate; 602, center tube; 603, diversion pipe; 604, diversion regulating valve; 605, regulating gear; 606, mounting frame; 607, drive motor; 608, drive gear; 609, upper docking gear; 610, lower docking gear; 611, mounting ring; 7, dehumidification assembly; 701, shell; 702, air inlet pump; 703, air inlet cover; 704, dewatering filter; 705, air outlet cover; 706, reversing valve; 707, exhaust pipe; 708, air outlet pipe. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figure 1In an embodiment of the present invention, a closed supercooled liquid nitrogen circulation device suitable for a superconducting shunt reactor includes a Dewar assembly 1 for containing liquid nitrogen, a circulation assembly 4 for driving the circulation of liquid nitrogen, and a refrigeration assembly for refrigerating liquid nitrogen. The Dewar assembly 1 includes a heat insulation box 101, a Dewar tank 5 is arranged in the heat insulation box 101, and the reactor is arranged in the Dewar tank 5; the superconducting shunt reactor targeted by the present application includes a glass fiber G10 skeleton and a high-temperature superconducting tape; conventional hollow superconducting reactors face the problem of magnetic leakage. Although traditional magnetic shielding can suppress spatial magnetic leakage, it will lead to an increase in the operating loss of the reactor and cause changes in the inductance parameters. Therefore, a toroidal reactor structure is selected to reduce magnetic leakage.

[0019] See also Figure 1 and Figure 2 , a liquid inlet pipe 102 is fixedly connected to the top of one side of the heat insulation box 101, and a liquid outlet pipe 103 is fixedly connected to the bottom of one side of the heat insulation box 101; the refrigeration assembly includes a Stirling refrigerator 2 and a water cooling unit 3 for dissipating heat from the Stirling refrigerator 2, and the above-mentioned Stirling refrigerator 2 and water cooling unit 3 are implemented by existing technical means. The liquid nitrogen in the Dewar tank 5 flows into the circulation pipe 401 through the liquid outlet valve 41, and the circulation power is provided by the liquid nitrogen pump 43, and is diverted to the liquefaction chamber of the Stirling refrigerator 2 through the circulation pipe 401. After passing through the liquefaction chamber, the liquid nitrogen is cooled from the original 77K to 70K, reaching a supercooled state, and then flows into the interior of the Dewar tank 5 from the liquid inlet valve 48 through the circulation pipe 401, so as to form a cycle, thereby achieving the purpose of supercooling the liquid nitrogen inside the Dewar tank 5. The whole system is connected to the electric control cabinet, which includes a data acquisition system, a control screen, a communication module and a safety shutdown system. The signals of the whole system are automatically controlled by the PLC inside the control cabinet, which can realize remote and local dual control, thereby realizing precise control of the refrigeration system, ensuring reliable operation and convenient operation and maintenance.

[0020] See also Figure 2 and Figure 3 , the circulation assembly 4 includes a circulation pipe 401 for connecting the Dewar assembly 1 and the refrigeration assembly, and the two ends of the circulation pipe 401 are respectively connected to the liquid outlet pipe 103 and the liquid inlet pipe 102; in order to reduce the temperature change of the liquid nitrogen during the pipeline transportation process, to reduce the heat conduction between the liquid nitrogen and the external environment during the liquid nitrogen transportation process, and to reduce the pipeline vibration noise during the liquid nitrogen transportation process; please refer to Figure 6 The outer wall of the circulation pipe 401 is covered with a heat insulation pad 402, and the outer wall of the heat insulation pad 402 is fixedly connected with an outer protective sleeve 403; See also Figure 1On one side of the circulation pipe 401 close to the liquid outlet pipe 103 of the Dewar assembly 1, a liquid outlet valve 41, a pressure gauge 42-1 before the pump, a liquid nitrogen pump 43, a pressure gauge 42-2 after the pump, a relief valve 44, an electric regulating valve 45, a liquid nitrogen valve 46, a temperature sensor 47 and a pressure gauge 42-3 after the valve are installed in sequence along the liquid nitrogen flow direction; the pressure gauge 42-1 before the pump, the pressure gauge 42-2 after the pump and the pressure gauge 42-3 after the valve monitor the pressure before the liquid nitrogen pump 43, the pressure after the liquid nitrogen pump 43 and the pressure after the liquid nitrogen valve 46 respectively; the electric regulating valve 45 is used to control the flow rate of circulating liquid nitrogen; the temperature sensor 47 is used to monitor the temperature of the liquid nitrogen after the electric regulating valve 45; the liquid nitrogen valve 46 is used to prevent the pipeline pressure from being too high.

[0021] A liquid inlet valve 48 is fixedly installed on one side of the circulation pipe 401 close to the liquid inlet end of the Dewar assembly 1. Through the setting of pressure gauges and valves at various positions, the temperature and pressure of each key measuring point of the superconducting magnet and the refrigeration system are monitored in real time to understand the operating status of the monitoring system. At the same time, high-precision control and automated operation can be achieved, effectively improving the working stability and reliability of the supermagnet.

[0022] See also Figure 3 A supporting platform 108 is fixedly installed at the bottom of the inner wall of the heat insulation box 101. The top surface of the supporting platform 108 is recessed downward to form an arc groove. The Dewar tank 5 is placed in the arc groove on the supporting platform 108. The inner wall shape of the arc groove is consistent with the bottom shape of the Dewar tank 5, thereby achieving stable support for the Dewar tank 5.

[0023] In order to reduce the heat conduction between the Dewar tank 5 and the external environment, a cover 104 is fixedly installed on the top of the insulation box 101, and an airtight ring 105 is fixedly connected to the edge of the cover 104, so that the gap between the cover 104 and the insulation box 101 is covered by the airtight ring 105; a lifting ring 107 is fixedly connected to the top of the cover 104 to facilitate the opening of the cover 104.

[0024] In order to improve the sealing ability of the cover 104 to the insulation box 101, the top edge of the cover 104 is rotatably connected with a plurality of locking bolts, and the top edge of the insulation box 101 is provided with a plurality of bolt holes 106, and the bottoms of the plurality of locking bolts are respectively threadedly connected with the plurality of bolt holes 106, so as to avoid reducing internal nitrogen leakage.

[0025] See also Figure 3 and Figure 4In order to avoid the problem of a liquid nitrogen dead zone inside the Dewar tank 5 caused by liquid nitrogen being delivered from a single position; a diverter assembly 6 is fixedly installed on the top of the Dewar tank 5, and the diverter assembly 6 includes a diverter cover plate 601, a central tube 602 is fixedly connected to the top of the diverter cover plate 601, and a plurality of diverter pipes 603 are fixedly connected to the bottom of the central tube 602, and a diverter regulating valve 604 is fixedly connected to the middle of the plurality of diverter pipes 603. The present application arranges a plurality of diverter pipes 603 to deliver liquid nitrogen from different positions, and cooperates with the diverter regulating valve 604 to adjust the delivery flow of each diverter pipe 603, thereby changing the liquid nitrogen delivery amount of different diverter pipes 603, so that the liquid nitrogen inside the Dewar tank 5 can flow slowly under the impetus of the liquid nitrogen delivered from different positions, thereby avoiding the formation of a dead zone.

[0026] In order to achieve synchronous regulation of the flow rates of the three shunt pipes 603, it is ensured that the liquid nitrogen fed by the liquid inlet pipe 102 can enter at a stable flow rate, thereby ensuring the stability of the pipeline pressure and the circulation flow rate of the liquid nitrogen; the middle part of the central pipe 602 is rotatably connected with a mounting collar 611, the bottom of the mounting collar 611 is fixedly connected with a lower docking gear 610, and the regulating ends of several shunt regulating valves 604 are fixedly connected with regulating gears 605, and several regulating gears 605 are all meshed and connected with the lower docking gear 610; the top of the mounting collar 611 is fixedly connected with an upper docking gear 609, the upper part of the mounting collar 611 is fixedly connected with a mounting frame 606, one side of the mounting frame 606 is fixedly connected with a driving motor 607, the output end of the driving motor 607 is fixedly connected with a driving gear 608, and the driving gear 608 is meshed with the upper docking gear 610. The gear 609 is meshed and connected; the present application sets an adjusting gear 605 at the adjusting end of each shunt regulating valve 604, drives the adjusting gear 605 to rotate through the driving motor 607 and other structures, and synchronously adjusts each shunt regulating valve 604. The initial opening state of each shunt regulating valve 604 is different, that is, when part of the shunt regulating valve 604 is gradually opened due to the rotation of the adjusting gear 605, the other part is gradually closed due to the rotation of the adjusting gear 605, so that the total liquid nitrogen flow rate passing through each shunt pipe 603 as a whole is consistent with the liquid nitrogen flow rate sent into the liquid inlet pipe 102, so as to ensure the stability of the overall circulation of liquid nitrogen; that is, the shunt assembly 6 set in the present application only changes the individual delivery flow rate of each shunt pipe 603, so as to guide the flow of liquid nitrogen in the Dewar tank 5 and avoid the formation of a dead zone.

[0027] See also Figure 3The middle part of the liquid inlet pipe 102 is bent in an arc shape, one end of the liquid inlet pipe 102 close to the circulation pipe 401 is horizontally arranged and fixedly connected to the circulation pipe 401, and the bottom of the liquid inlet pipe 102 is vertically arranged and fixedly connected to the top of the central pipe 602; by bending the liquid inlet pipe 102 in an arc shape, the liquid nitrogen flows more smoothly in the pipeline, avoiding the problem of vibration caused by the small angle bending of the pipeline when the liquid nitrogen flows through, thereby improving the operation stability of the device.

[0028] When in use, the device is installed in a closed indoor working environment. Figure 2 and Figure 5 In order to facilitate the working process, the water vapor in the air condenses on the surface of the pipeline or other components due to low temperature, thereby affecting the normal working performance of the device. In this application, a dehumidification component 7 is fixedly installed on one side of the heat insulation box 101. The dehumidification component 7 includes a shell 701, and an air inlet cover 703 is fixedly connected to the top of the shell 701, and an air outlet cover 705 is fixedly connected to one side of the shell 701. The bottom of the air inlet cover 703 is fixedly connected to an air inlet pipe, and the bottom of the air inlet pipe is fixedly connected to an air inlet pump 702. The output end of the air inlet pump 702 is fixedly connected to an air outlet pipe 708, one end of the air outlet pipe 708 is fixedly connected to the air outlet cover 705, and a dewatering filter 704 is fixedly installed in the middle of the air outlet pipe 708; by setting up the dewatering component, the air inlet pump 702 is used to draw in the outside air, and the dewatering filter 704 is used to filter and remove the water vapor in the air of the closed working environment, so as to reduce the moisture content of the ambient air, thereby effectively avoiding the condensation of water vapor on the pipeline equipment.

[0029] In order to filter the water vapor inside the heat insulation box 101, a reversing valve 706 is fixedly installed in the middle of the air inlet pipe, and one end of the reversing valve 706 is fixedly connected to an exhaust pipe 707. One end of the exhaust pipe 707 is connected to the interior of the heat insulation box 101. The connection direction of the air inlet pipe is changed by the reversing valve 706, and the air inside the heat insulation box 101 is extracted through the exhaust pipe 707, thereby removing the water vapor inside the heat insulation box 101.

[0030] The working method of the closed supercooled liquid nitrogen circulation device comprises the following steps: first, check whether the instruments of each device are normal; after completing the overall packaging of the reactor and the Dewar tank 5, perform a leak test on the Dewar assembly 1, specifically: perform a 0.05MPa airtightness test on the Dewar tank 5 and maintain the pressure for 20 minutes; then perform vacuum replacement, use a vacuum pump to evacuate to 0.1Pa, maintain the pressure for 30 minutes, and then fill with nitrogen to 0.02MPa, maintain the pressure for 30 minutes, and repeat this 3 times; finally, slowly add liquid nitrogen; Then, the circulation pipe 401 is checked for leaks. First, the Dewar assembly 1 is connected to the refrigeration assembly. Specifically, the cover 104 is opened, and the Dewar tank 5 together with the diverter assembly 6 thereon is loaded into the heat-insulating box 101, and the support 108 receives it. Then, the liquid inlet pipe 102 and the liquid outlet pipe 103 are respectively fixedly connected with the two ends of the circulation pipe 401; after completion, the cover 104 is installed, and then several locking bolts are turned to fix the cover 104 with the heat-insulating box 101; then the liquid outlet valve 41 is opened, and the circulation pipe 401 and the entire circulation assembly 4 are checked for leaks by the flow of liquid nitrogen; since the working pressure of the entire system pipeline is relatively low, foam water can be used to check for leaks on each instrument and valve assembly and the connection points with the pipeline to ensure that the entire system is leak-free; Then, the circulation pipe 401 is precooled, and the electric regulating valve 45, the relief valve 44 and the branch low-temperature electromagnetic valve inside the Stirling refrigerator 2 are opened in sequence, and then the liquid outlet valve 41 is gradually and slowly opened, and then the liquid nitrogen will flow into the circulation pipe 401 through the liquid outlet valve 41; precooling is performed until the temperature sensor 47 shows that the temperature is -196°C, indicating that the inside of the circulation pipe 401 has been precooled; The equipment starts to run for refrigeration. First, turn on the water cooling unit 3, then gradually and slowly open the relief valve 44, observe the outlet status of the relief valve 44, if all columnar liquid nitrogen is sprayed out, turn on the liquid nitrogen pump 43, and note that the operating frequency of the liquid nitrogen pump 43 needs to gradually increase from 20HZ to 100HZ; at this time, the pressure gauge 42-3 after the valve observes that the liquid nitrogen pressure at the outlet of the relief valve 44 will increase significantly, and the relief valve 44 needs to be closed at this time. After closing the relief valve 44, observe the pressure gauge 42-1 before the pump and the pressure gauge 42-2 after the pump, wait for the pressure before and after the liquid nitrogen pump 43 to stabilize, and after the liquid nitrogen pump 43 runs stably, turn on the Stirling refrigerator 2, and the Stirling refrigerator 2 moves to continuously cool the liquid nitrogen in the circulation pipe 401 to ensure the stable operation of the superconductor in the Dewar tank 5; During the operation of the equipment, the reciprocating rotation of the driving motor 607 drives the adjusting gears 605 to rotate, thereby opening and closing the shunt regulating valves 604, thereby changing the liquid nitrogen output of each shunt pipe 603, driving the liquid nitrogen flow inside the Dewar tank 5 to avoid the formation of a dead zone.

[0031] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A closed supercooled liquid nitrogen circulation device suitable for superconducting shunt reactors, characterized in that: It comprises a Dewar assembly (1) for containing liquid nitrogen, a circulation assembly (4) for driving the circulation of liquid nitrogen, and a refrigeration assembly for refrigerating the liquid nitrogen; The circulation assembly (4) comprises a circulation pipe (401) for connecting the Dewar assembly (1) and the refrigeration assembly; a liquid outlet valve (41), a pump front pressure gauge (42-1), a liquid nitrogen pump (43), a pump rear pressure gauge (42-2), a relief valve (44), an electric regulating valve (45), a liquid nitrogen valve (46), a temperature sensor (47) and a valve rear pressure gauge (42-3) are sequentially installed on the side of the circulation pipe (401) close to the liquid outlet end of the Dewar assembly (1) along the liquid nitrogen flow direction; a liquid inlet valve (48) is fixedly installed on the side of the circulation pipe (401) close to the liquid inlet end of the Dewar assembly (1); and the refrigeration assembly comprises a Stirling refrigerator (2) and a water cooling unit (3) for dissipating heat from the Stirling refrigerator (2).

2. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 1, characterized in that: The Dewar assembly (1) comprises a heat-insulating box (101), a support platform (108) being fixedly mounted on the bottom of the inner wall of the heat-insulating box (101), a Dewar tank (5) being placed on the support platform (108), a sealing cover (104) being fixedly mounted on the top of the heat-insulating box (101), and an airtight ring sleeve (105) being fixedly connected to the edge of the sealing cover (104).

3. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 2, characterized in that: The top edge of the cover (104) is rotatably connected to a plurality of locking bolts, the top edge of the heat insulation box (101) is provided with a plurality of bolt holes (106), and the bottoms of the plurality of locking bolts are respectively threadedly connected to the plurality of bolt holes (106).

4. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 2, characterized in that: A flow diversion assembly (6) is fixedly mounted on the top of the Dewar tank (5), the flow diversion assembly (6) comprising a flow diversion cover plate (601), the top of the flow diversion cover plate (601) is fixedly connected to a central tube (602), the bottom of the central tube (602) is fixedly connected to a plurality of flow diversion tubes (603), and the middle portions of the plurality of flow diversion tubes (603) are fixedly connected to flow diversion regulating valves (604).

5. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 4, characterized in that: The middle part of the central tube (602) is rotatably connected to a mounting collar (611), the bottom of the mounting collar (611) is fixedly connected to a lower docking gear (610), the regulating ends of a plurality of the diversion regulating valves (604) are fixedly connected to regulating gears (605), and the plurality of regulating gears (605) are meshingly connected to the lower docking gear (610), the top of the mounting collar (611) is fixedly connected to an upper docking gear (609), the upper part of the mounting collar (611) is fixedly connected to a mounting frame (606), one side of the mounting frame (606) is fixedly connected to a driving motor (607), the output end of the driving motor (607) is fixedly connected to a driving gear (608), and the driving gear (608) is meshingly connected to the upper docking gear (609).

6. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 2, characterized in that: A liquid inlet pipe (102) is fixedly connected to the top of one side of the heat insulation box (101); the middle portion of the liquid inlet pipe (102) is arranged in an arc shape; one end of the liquid inlet pipe (102) close to the circulation pipe (401) is arranged horizontally and is fixedly connected to the circulation pipe (401); the bottom of the liquid inlet pipe (102) is arranged vertically and is fixedly connected to the top of the central pipe (602).

7. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 2, characterized in that: A dehumidification component (7) is fixedly installed on one side of the heat insulation box (101), and the dehumidification component (7) comprises a shell (701), the top of the shell (701) is fixedly connected to an air inlet cover (703), one side of the shell (701) is fixedly connected to an air outlet cover (705), the bottom of the air inlet cover (703) is fixedly connected to an air inlet pipe, the bottom of the air inlet pipe is fixedly connected to an air inlet pump (702), the output end of the air inlet pump (702) is fixedly connected to an air outlet pipe (708), one end of the air outlet pipe (708) is fixedly connected to the air outlet cover (705), and a dewatering filter (704) is fixedly installed in the middle of the air outlet pipe (708).

8. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 7, characterized in that: A reversing valve (706) is fixedly installed in the middle of the air inlet pipe, one end of the reversing valve (706) is fixedly connected to an exhaust pipe (707), and one end of the exhaust pipe (707) is in communication with the interior of the heat insulation box (101).

9. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 1, characterized in that: The outer wall of the circulation pipe (401) is coated with a heat insulation pad (402), and the outer wall of the heat insulation pad (402) is fixedly connected with an outer protective sleeve (403).

10. A closed type supercooled liquid nitrogen circulation device suitable for superconducting shunt reactor according to claim 1, characterized in that: The working method of the closed subcooled liquid nitrogen circulation device comprises the following steps: Step 1: Leakage test the Dewar assembly (1), perform a 0.05MPa airtightness test on the Dewar tank (5) and maintain the pressure for 20 minutes; then perform vacuum replacement, use a vacuum pump to evacuate to 0.1Pa, maintain the pressure for 30 minutes, then fill with nitrogen to 0.02MPa, maintain the pressure for 30 minutes, and repeat this process 3 times; finally, add liquid nitrogen; Step 2: Leakage detection of the circulation pipe (401). After the circulation assembly (4) is connected to the Dewar assembly (1) and the refrigeration assembly, the liquid outlet valve (41) is opened and the circulation pipe (401) and the entire circulation assembly (4) are leak-detected by flowing liquid nitrogen. Step 3: precooling the circulation pipe (401), opening the electric regulating valve (45), the relief valve (44) and the branch low-temperature solenoid valve inside the Stirling refrigerator (2) in sequence, and then gradually opening the liquid outlet valve (41), at which time liquid nitrogen will flow into the circulation pipe (401) through the valve; precooling until the temperature sensor (47) displays a temperature of -196°C, indicating that the inside of the circulation pipe (401) has been precooled; Step 4: Run the refrigeration, first turn on the water cooling unit (3), then gradually open the relief valve (44), observe the outlet status of the relief valve (44), if all the liquid nitrogen is sprayed out in a columnar shape, then turn on the liquid nitrogen pump (43), wait for the liquid nitrogen pump (43) to run stably, and then turn on the Stirling refrigerator (2).

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