Thermomagnetic fault maintenance system of superconducting magnet

Abstract

The utility model discloses a thermomagnetic fault maintenance system of a superconducting magnet, which comprises a temperature sensor arranged in the superconducting magnet and used for acquiring the temperature of a superconducting coil; the cleaning device is communicated with a magnet cavity formed in the inner layer of the Dewar flask, and the cleaning device is used for cleaning impurities in the magnet cavity; the helium circulating pre-cooling device is communicated with the magnet cavity and is used for circularly filling and discharging helium into and out of the magnet cavity so as to pre-cool the magnet cavity; the liquid helium supply device is communicated with the magnet cavity and used for filling liquid helium into the magnet cavity, the system does not need to consume a large amount of liquid nitrogen and liquid helium to maintain thermomagnetic faults of the superconducting magnet, the material consumption is reduced, the labor cost is saved, and the maintenance speed is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of superconducting magnet maintenance, in particular to a thermal magnetic fault maintenance system for a superconducting magnet. Background Art

[0002] At present, magnetic resonance imaging (MRI) equipment mainly uses superconducting magnets, and the material characteristics of the magnets determine that the magnet quench is inevitable. With the increasing popularity of magnetic resonance imaging equipment, its installation / use environment is becoming more and more complex, and the complex use environment increases the probability of magnet quench.

[0003] After the magnet quenches its supersonic force, if the liquid helium is consumed and the low temperature provided by the cryogenic liquid helium is lost, the magnet will experience internal temperature rise. If the temperature is too high, the magnet will experience thermal magnetic failure. Traditionally, when repairing thermal magnetic failures, it is usually pre-cooled by filling it with liquid nitrogen or liquid helium. During the pre-cooling process, a large amount of liquid nitrogen and liquid helium is consumed, a large amount of manpower is invested, and the cost is high. Utility Model Content

[0004] The utility model aims to solve the problem that a large amount of liquid nitrogen and liquid helium are consumed during the current traditional thermal magnetic fault repair.

[0005] To achieve the above object, the utility model discloses a thermal magnetic fault repair system for a superconducting magnet, wherein the superconducting magnet comprises a dewar flask with inner and outer double layers and a superconducting coil arranged in the inner layer of the dewar flask, and the thermal magnetic fault repair system comprises:

[0006] A temperature sensor is disposed in the superconducting magnet, and is used to obtain the temperature of the superconducting coil;

[0007] A cleaning device, connected to the magnet cavity formed by the inner layer of the Dewar flask, and used for cleaning impurities in the magnet cavity;

[0008] a helium circulation precooling device, connected to the magnet cavity, for cyclically filling and discharging helium into and out of the magnet cavity to precool the magnet cavity;

[0009] A liquid helium supply device is communicated with the magnet cavity and is used for filling the magnet cavity with liquid helium.

[0010] In this solution, when repairing the thermal magnetic fault of the superconducting magnet, helium pre-cooling is used instead of liquid helium pre-cooling, which greatly saves material consumption in the process of repairing the thermal magnetic fault and shortens the repair time.

[0011] Optionally, the thermal-magnetic fault repair system also includes a first vacuum pump, which is connected to the first space between the inner and outer double layers of the Dewar flask, and is used to evacuate the first space to a vacuum state, thereby rebuilding the vacuum state of the first space, ensuring better results when pre-cooling the superconducting magnet subsequently, and ensuring that the superconducting coil can work normally after subsequent recovery to normal.

[0012] Optionally, the cleaning device includes a second vacuum pump and a cleaning gas supply device, the second vacuum pump is connected to the magnet cavity, and the cleaning gas supply device is connected to the magnet cavity through the second vacuum pump; the second vacuum pump is used to extract the gas in the magnet cavity and to fill the cleaning gas in the cleaning gas supply device into the magnet cavity. This solution avoids ice impurities generated when cooling the superconducting coil, which affects the operation of the superconducting magnet.

[0013] Optionally, the cleaning gas supply device is a helium supply device, and the cleaning gas is helium. Helium is used as the cleaning gas, which is the same as the substance required for the normal operation of the pre-cooling magnet cavity and the superconducting coil, to avoid the introduction of other impurity gases.

[0014] Optionally, the temperature of the helium filled into the magnet cavity by the helium circulation precooling device is 30K, thereby reducing the temperature of the magnet cavity and the superconducting coil to a lower temperature, achieving a precooling effect.

[0015] Optionally, the thermal magnetic fault repair system has a plurality of temperature sensors, which are arranged on the surface and / or inside of the superconducting coil. This solution can more accurately obtain the temperature of the superconducting coil by measuring the temperature of multiple positions of the superconducting coil.

[0016] Optionally, the helium circulation precooling device includes a dewar unit, a circulation pump and a compressor, wherein the dewar unit stores helium; the dewar unit is connected to the magnet cavity, and the circulation pump is connected between the dewar unit and the magnet cavity; a cold head is provided in the dewar unit, and the cold head is connected to a compressor outside the dewar unit, and the compressor circulates a cooling medium to the cold head to cool the helium in the dewar unit. In this solution, the compressor and the cold head are used to refrigerate the helium, and the refrigerated helium is circulated and transported to the magnet cavity to precool the magnet cavity, so that the helium is recycled, consumption is reduced, labor costs are saved, and maintenance time is fast.

[0017] Optionally, the circulation pump is a molecular vacuum pump, which can quickly achieve a high vacuum effect.

[0018] Optionally, the helium circulation pre-cooling device includes a plurality of the compressors, a plurality of cold heads are provided in the Dewar tank unit, and the compressors correspond to the cold heads one by one, thereby increasing the cooling speed of the helium.

[0019] Optionally, the helium circulation pre-cooling device further comprises a heater, which is arranged inside the dewar tank unit. The heater cooperates with the cold head to quickly and accurately control the helium temperature inside the dewar tank unit.

[0020] In summary, compared with the prior art, the utility model has the following advantages and beneficial effects:

[0021] This solution adopts a thermal magnetic fault maintenance system including a temperature sensor, a cleaning device, a helium circulation precooling device and a liquid helium supply device, which monitors the temperature of the magnet cavity in turn, cleans the impurity gas in the magnet cavity, uses helium to circulate and precool the magnet cavity, and supplies liquid helium, without consuming a large amount of liquid nitrogen and liquid helium, reducing material consumption, saving labor costs, and improving maintenance speed;

[0022] This solution uses a first vacuum pump to rebuild the vacuum environment of the first space, so that the subsequent pre-cooling of the superconducting magnet has a better effect, and also ensures that the superconducting coil can work normally after the subsequent recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a thermal magnetic fault repair system for a superconducting magnet according to an embodiment of the utility model;

[0024] Figure 2 This is a schematic diagram of a thermal-magnetic fault repair system for a superconducting magnet according to another embodiment of the utility model.

[0025] Description of reference numerals:

[0026] 100 First Space

[0027] 100a Outer layer

[0028] 100b inner layer

[0029] 200 Magnet Chamber

[0030] 300 Superconducting Coil

[0031] 400 Temperature Sensor

[0032] 510 Second vacuum pump

[0033] 511 Gas outlet

[0034] 520 Cleaning gas supply device

[0035] 600 First Vacuum Pump

[0036] 710 Circulation Pump

[0037] 720 Dewar Unit

[0038] 721 Cold Head

[0039] 730 Compressor DETAILED DESCRIPTION

[0040] The technical scheme, structural features, achieved objectives and effects of the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0041] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the implementation methods of the utility model, and are not used to limit the conditions for the implementation of the utility model. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the utility model without affecting the efficacy and purpose that can be achieved by the utility model.

[0042] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0043] Magnetic resonance imaging (MRI) equipment mainly uses superconducting magnets. When the superconducting magnet loses its superconductivity, if the liquid helium is also completely consumed, the superconducting magnet will heat up and cause a thermal magnetic failure. At present, when repairing the thermal magnetic failure of a superconducting magnet, after eliminating the cause of the failure, a large amount of liquid nitrogen and liquid helium are usually used to pre-cool the superconducting magnet in stages. First, liquid nitrogen is introduced to pre-cool the magnet, and then liquid helium is gradually introduced to cool the magnet. This process not only requires a lot of manpower, but also has a very high cost.

[0044] In order to solve the above problems, the utility model proposes a superconducting magnet thermal magnetic fault repair system, which is used to perform thermal magnetic fault repair on superconducting magnets. Figure 1As shown, the superconducting magnet includes a Dewar flask and a superconducting coil 300 arranged in the Dewar flask. The wall of the Dewar flask has a double layer, including an outer layer 100a and an inner layer 100b. A first space 100 is formed between the outer layer 100a and the inner layer 100b. A magnet cavity 200 is formed inside the inner layer 100b. The superconducting coil 300 is located in the magnet cavity 200. The thermal magnetic fault repair system of this embodiment includes: a temperature sensor 400, which is arranged in the superconducting magnet and is used to monitor the temperature of the superconducting coil 300; a cleaning device, which is connected to the magnet cavity 200 in the superconducting magnet, and is used to clean impurities in the magnet cavity 200 to avoid ice impurities when the superconducting magnet is subsequently cooled; a helium circulation precooling device, which is also connected to the magnet cavity 200 in the superconducting magnet, and the helium circulation precooling device circulates helium into and discharges the magnet cavity 200 to precool the magnet cavity 200 and the superconducting coil 300; a liquid helium supply device, which is also connected to the magnet cavity 200 in the superconducting magnet, and is used to fill liquid helium into the magnet cavity 200.

[0045] The thermal magnetic fault repair system further includes a first vacuum pump 600, which is connected to the first space 100 and can evacuate the first space 100. When the superconducting magnet is working normally, the first space 100 should be a high vacuum area to reduce heat conduction and heat convection, so as to maintain the low temperature environment of the magnet cavity 200 and ensure that the superconducting coil 300 is in a superconducting state. When a thermal magnetic fault occurs in a superconducting magnet, it is often accompanied by a decrease in the vacuum of the first space 100, so the first vacuum pump 600 is set to re-establish the vacuum environment of the first space 100 to ensure a better effect when pre-cooling the superconducting magnet later.

[0046] The thermal magnetic fault repair system has a plurality of temperature sensors 400, which are arranged on the surface of the superconducting coil 300 or inside the superconducting coil 300. In other embodiments, the plurality of temperature sensors 400 are arranged on the surface of the superconducting coil 300 and inside the superconducting coil 300. The utility model does not limit the number of the temperature sensors 400, and in this embodiment, there are 4 temperature sensors.

[0047] The temperature sensor 400 is used to monitor whether the temperature of the superconducting coil 300 has reached normal temperature. In order to obtain a better effect when the vacuum of the first space 100 is rebuilt using the first vacuum pump 600, it should be ensured that the temperature of the superconducting coil 300 has reached normal temperature. When there are multiple temperature sensors 400, it should be ensured that the temperature measured by each temperature sensor 400 has reached normal temperature. In this embodiment, the normal temperature is room temperature.

[0048] The cleaning device is used to clean the impurity gas in the magnet cavity 200. The cleaning device includes a second vacuum pump 510, which is connected to the magnet cavity 200. The second vacuum pump 510 also has a gas outlet 511. When the second vacuum pump 510 extracts the impurity gas in the magnet cavity 200, the second vacuum pump 510 extracts the impurity gas in the magnet cavity 200 and discharges it through the gas outlet 511. At this time, the magnet cavity 200 is in a negative pressure state.

[0049] Furthermore, the cleaning device further includes a cleaning gas supply device 520, which is connected to the second vacuum pump 510, so that the cleaning gas supply device 520 is connected to the magnet cavity 200 through the second vacuum pump 510; when the second vacuum pump 510 extracts the impurity gas in the magnet cavity 200, the magnet cavity 200 is approximately vacuum, but there will still be impurity gas remaining therein. In order to thoroughly clean it, the second vacuum pump 510 fills the cleaning gas in the cleaning gas supply device 520 into the magnet cavity 200, and then the second vacuum pump 510 is used to extract the gas in the magnet cavity 200 and discharge it through the gas outlet 511. Repeat this 4 to 5 times to clean the impurity gas in the magnet cavity 200. When the cleaning gas is filled into the magnet cavity 200, the gas outlet 511 is closed to prevent the cleaning gas from leaking out; when the gas in the magnet cavity 200 is extracted, the channel between the cleaning gas supply device 520 and the second vacuum pump 510 is closed to prevent the impurity gas from contaminating the cleaning gas supply device 520.

[0050] The cleaning gas supply device 520 is a helium supply device, which provides helium as cleaning gas. Since a helium circulation precooling device is used for precooling the magnet cavity 200 later, and the superconducting coil 300 is in a liquid helium environment when it is working normally, the use of helium as cleaning gas is the same as the material required for precooling the magnet cavity 200 and the normal operation of the superconducting coil 300, thereby avoiding the introduction of other impurity gases.

[0051] The helium circulation precooling device comprises a dewar tank unit 720, a circulation pump 710 and a compressor 730, wherein the dewar tank unit 720 stores helium, the dewar tank unit 720 is connected to the circulation pump 710, the circulation pump 710 is communicated with the magnet cavity 200, the helium in the dewar tank unit 720 is transported to the magnet cavity 200 by the circulation pump 710, and the helium in the magnet cavity 200 is pumped into the dewar tank unit 720 by the circulation pump 710, so that the helium completes a cycle between the dewar tank unit 720 and the magnet cavity 200. The low-temperature helium is transported from the dewar tank unit 720 to the superconducting coil 300 in the magnet cavity 200 by the circulation pump 710 for precooling, at which time the temperature of the helium rises, and is transported from the magnet cavity 200 to the dewar tank unit 720 by the circulation pump 710 to be cooled again, and the process is circulated until the precooling of the superconducting coil 300 is completed. In this embodiment, the circulation pump 710 is a molecular vacuum pump.

[0052] The compressor 730 is arranged outside the dewar unit 720. A cold head 721 for cooling helium is provided inside the dewar unit 720. The cold head 721 is connected to the external compressor 730. The compressor 730 circulates cooling medium into the cold head 721 to cool the helium in the dewar unit 720.

[0053] Furthermore, the dewar unit 720 has a helium inlet and a helium outlet, both of which are connected to the magnet cavity 200. Under the action of the circulating pump 710, helium is transported from the dewar unit 720 into the magnet cavity 200 via the helium outlet, and then transported from the magnet cavity 200 into the dewar unit 720 via the helium inlet.

[0054] In order to cool the helium in the dewar unit 720 to the required temperature as quickly as possible, a plurality of cold heads 721 and compressors 730 are provided, and the cold heads 721 and compressors 730 correspond one to one; the plurality of cold heads 721 cool the helium simultaneously.

[0055] The cold head 721 cools the helium in the dewar unit 720 to 30K (−243° C.), that is, fills the magnet cavity 200 with 30K helium.

[0056] like Figure 2 As shown, in another embodiment, each device is the same as the above embodiment, except that the helium circulation precooling device also includes a heater 722, which is arranged in the dewar tank unit 720 and is used to heat the helium. The heater 722 cooperates with the cold head 721 to keep the helium temperature in the dewar tank unit 720 at 30K. Further, a temperature monitor (not shown in the figure) is also provided in the dewar tank unit 720 to measure the helium temperature in the dewar tank unit 720 to ensure that the helium temperature therein is at 30K.

[0057] When the thermal magnetic fault repair system of a superconducting magnet of the utility model is used to repair a thermal magnetic fault of a superconducting magnet, the following steps are included:

[0058] S100, using the temperature sensor 400 to monitor whether the temperature of the superconducting coil 300 reaches room temperature, if it reaches room temperature, proceed to the next step, if it does not reach room temperature, wait for the temperature of the superconducting coil 300 to reach room temperature;

[0059] S200, using the first vacuum pump 600 to evacuate the first space 100 to restore the vacuum state of the superconducting magnet;

[0060] S300, using a cleaning device to clean the impurity gas in the magnet cavity 200: the second vacuum pump 510 extracts the impurity gas in the magnet cavity 200, and then fills the cleaning gas in the cleaning gas supply device 520 into the magnet cavity 200, repeating 4 to 5 times to clean the impurity gas in the magnet cavity 200;

[0061] S400, precooling the magnet cavity 200 by using a helium circulation precooling device: low-temperature helium is transported from the dewar tank unit 720 to the superconducting coil 300 in the magnet cavity 200 by the circulation pump 710 for precooling, at which time the temperature of the helium rises, and the heated helium is transported from the magnet cavity 200 to the dewar tank unit 720 by the circulation pump 710 to be cooled again, and the process is circulated until the precooling of the superconducting coil 300 is completed;

[0062] S500: The liquid helium supply device fills the magnet cavity 200 with liquid helium until the liquid helium reaches the liquid level for clinical use of the magnetic resonance device.

[0063] When the superconducting magnet is operating normally, the first space 100 should be a high vacuum zone to reduce heat conduction and heat convection, thereby maintaining the low temperature environment of the magnet cavity 200 and ensuring that the superconducting coil 300 is in a superconducting state. When a thermal magnetic failure occurs in the superconducting magnet, the vacuum property of the first space 100 is often reduced. Therefore, rebuilding the vacuum environment of the first space 100 through step S200 can ensure better results when pre-cooling the superconducting magnet subsequently, and ensure that the superconducting coil 300 can operate normally after recovery.

[0064] When a thermal magnetic fault occurs, there will be impurity gas contamination in the magnet cavity 200. If the impurity gas in the magnet cavity 200 is not cleaned and allowed to remain in the magnet cavity 200, since helium needs to be filled into the magnet cavity 200 for pre-cooling and liquid helium needs to be filled to keep the superconducting coil 300 in a superconducting state, if there is other gas in the magnet cavity 200 at this time, it will freeze when the superconducting coil 300 is cooled, thereby generating ice impurities and affecting the operation of the superconducting magnet. Therefore, the impurity gas in the magnet cavity 200 is cleaned through step S300.

[0065] It should be pointed out that although the utility model adopts a helium circulation precooling device to precool the magnet cavity, this is not a limitation on the precooling method. In other embodiments, the magnet cavity can still be precooled by a traditional combination of liquid nitrogen and liquid helium. Compared with the traditional precooling method, the helium circulation precooling device of the utility model has the advantages of low cost, fast precooling and labor saving.

[0066] Although the content of the utility model has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the utility model. After reading the above content, various modifications and substitutions of the utility model will be obvious to those skilled in the art. Therefore, the protection scope of the utility model should be limited by the attached claims.

Claims

1. A thermal magnetic fault repair system for a superconducting magnet, the superconducting magnet comprising a dewar flask with inner and outer double layers and a superconducting coil arranged in the inner layer of the dewar flask, characterized in that: The thermal magnetic fault repair system comprises: A temperature sensor is disposed in the superconducting magnet, and is used to obtain the temperature of the superconducting coil; A cleaning device, connected to the magnet cavity formed by the inner layer of the Dewar flask, and used for cleaning impurities in the magnet cavity; a helium circulation precooling device, connected to the magnet cavity, for cyclically filling and discharging helium into and out of the magnet cavity to precool the magnet cavity; A liquid helium supply device is communicated with the magnet cavity and is used for filling the magnet cavity with liquid helium.

2. The thermal magnetic fault repair system for a superconducting magnet according to claim 1, characterized in that: It also includes a first vacuum pump, which is connected to the first space between the inner and outer double layers of the Dewar flask and is used to evacuate the first space.

3. The thermal magnetic fault repair system for a superconducting magnet according to claim 1, characterized in that: The cleaning device includes a second vacuum pump and a cleaning gas supply device, the second vacuum pump is connected to the magnet cavity, and the cleaning gas supply device is connected to the magnet cavity through the second vacuum pump; the second vacuum pump is used to extract the gas in the magnet cavity, and is also used to fill the cleaning gas in the cleaning gas supply device into the magnet cavity.

4. The thermal magnetic fault repair system for a superconducting magnet according to claim 3, characterized in that: The cleaning gas supply device is a helium supply device, and the cleaning gas is helium.

5. The thermal magnetic fault repair system for a superconducting magnet according to claim 1, characterized in that: The temperature of the helium gas filled into the magnet cavity by the helium circulation precooling device is 30K.

6. The thermal magnetic fault repair system for a superconducting magnet according to claim 1, characterized in that: The thermal-magnetic fault repair system includes a plurality of the temperature sensors, and the plurality of the temperature sensors are arranged on the surface and / or inside of the superconducting coil.

7. The thermal magnetic fault repair system for a superconducting magnet according to claim 1, characterized in that: The helium circulation precooling device comprises a dewar tank unit, a circulation pump and a compressor, and helium is stored in the dewar tank unit; The Dewar unit is connected to the magnet cavity, and the circulation pump is connected between the Dewar unit and the magnet cavity; A cold head is arranged in the dewar unit, and the cold head is communicated with a compressor outside the dewar unit. The compressor circulates a cooling medium to the cold head to cool the helium in the dewar unit.

8. The thermal magnetic fault repair system for a superconducting magnet according to claim 7, characterized in that: The circulating pump is a molecular vacuum pump.

9. The thermal magnetic fault repair system for a superconducting magnet according to claim 7, characterized in that: The helium circulation precooling device comprises a plurality of the compressors, a plurality of cold heads are arranged in the dewar tank unit, and the compressors correspond to the cold heads one by one.

10. The thermal magnetic fault repair system for a superconducting magnet according to any one of claims 7 to 9, characterized in that: The helium circulation precooling device also includes a heater, which is arranged inside the Dewar tank unit.

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