Low-temperature refrigerating system and control method thereof

Abstract

The invention relates to the technical field of low-temperature superconducting power equipment, and particularly discloses a low-temperature refrigerating system and a control method thereof. The low-temperature refrigerating system comprises a low-temperature liquid storage tank, a refrigerating module and a liquid supplementing tank. Low-temperature liquid is stored in the low-temperature liquid storage tank; an air inlet of the refrigeration module is communicated with an air outlet of the low-temperature liquid storage tank through a first gas-phase pipeline, a liquid outlet of the refrigeration module is communicated with a liquid inlet of the low-temperature liquid storage tank through a first liquid-phase pipeline, the first gas-phase pipeline is provided with an air return valve used for controlling on-off of the first gas-phase pipeline, and the first liquid-phase pipeline is provided with a liquid return valve used for controlling on-off of the first liquid-phase pipeline; low-temperature liquid is stored in the liquid supplementing tank, a liquid outlet of the liquid supplementing tank is communicated with a liquid inlet of the low-temperature liquid storage tank through a second liquid phase pipeline, and a liquid supplementing valve used for controlling the second liquid phase pipeline to be connected and disconnected is arranged on the second liquid phase pipeline. According to the low-temperature refrigerating system, the two liquid supplementing modes of refrigerating module liquid supplementing and liquid supplementing tank liquid supplementing are combined, and the immersion condition of the superconducting power equipment in the low-temperature liquid storage tank can be effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature superconducting power equipment, and in particular to a low-temperature refrigeration system and a control method thereof. Background Art

[0002] Superconducting technology can only be realized by placing superconducting power equipment in a low-temperature environment. At present, most superconducting power equipment is cooled by immersing in cryogenic liquid. However, due to heat leakage in the cryogenic liquid storage tank, the cryogenic liquid in the cryogenic liquid storage tank will continue to evaporate and cause loss. Therefore, it is necessary to continuously replenish the cryogenic liquid in the cryogenic liquid storage tank.

[0003] There are two main traditional ways of replenishing liquid. One is to place the cold head of the refrigerator directly on the top of the cryogenic liquid storage tank to liquefy the vapor. However, when the refrigerator fails or the refrigerator is under maintenance, the cryogenic liquid immersion conditions of the superconducting power equipment cannot be guaranteed. The other is to replenish the cryogenic liquid with an external replenishment tank, but this method requires frequent replenishment, consumes a lot of manpower, and is difficult to automate.

[0004] Therefore, there is an urgent need to propose a low-temperature refrigeration system and a control method thereof to solve the above technical problems. Summary of the invention

[0005] According to one aspect of the present invention, a low-temperature refrigeration system is provided, which combines two replenishment methods, namely, replenishment of the refrigeration module and replenishment of the replenishment tank. This system can effectively ensure the immersion conditions of the superconducting power equipment in the low-temperature liquid storage tank, and does not require frequent replenishment, thereby saving labor costs and facilitating automated operation.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] Low temperature refrigeration system, including:

[0008] A cryogenic liquid storage tank, wherein the cryogenic liquid is stored in the cryogenic liquid, and the superconducting power device is immersed in the cryogenic liquid;

[0009] A refrigeration module, wherein the air inlet of the refrigeration module is connected to the air outlet of the cryogenic liquid storage tank via a first gas phase pipeline, the liquid outlet of the refrigeration module is connected to the liquid inlet of the cryogenic liquid storage tank via a first liquid phase pipeline, the first gas phase pipeline is provided with an air return valve for controlling its on-off, and the first liquid phase pipeline is provided with a liquid return valve for controlling its on-off;

[0010] A liquid replenishment tank is provided, wherein cryogenic liquid is stored in the liquid replenishment tank, a liquid outlet of the liquid replenishment tank is connected to a liquid inlet of the cryogenic liquid storage tank via a second liquid phase pipeline, and a liquid replenishment valve for controlling the on-off of the second liquid phase pipeline is provided on the second liquid phase pipeline.

[0011] Optionally, the refrigeration module comprises:

[0012] A refrigeration box, wherein a first air inlet of the refrigeration box is connected to the first gas phase pipeline, and a first liquid outlet of the refrigeration box is connected to the first liquid phase pipeline;

[0013] A refrigerator cold head is arranged in the refrigeration box;

[0014] A self-pressurizing valve, wherein the inlet of the self-pressurizing valve is connected to the second liquid outlet of the refrigeration box;

[0015] A self-pressurizing device, wherein the outlet of the self-pressurizing valve is connected to the pressurizing input end of the self-pressurizing device, and the pressurizing output end of the self-pressurizing device is connected to the second air inlet of the refrigeration box. The self-pressurizing device vaporizes the input low-temperature liquid and then outputs it.

[0016] Optionally, the first liquid phase pipeline includes a first liquid phase segment, a second liquid phase segment and a third liquid phase segment, the liquid outlet of the refrigeration module is connected to the inlet of the liquid return valve through the first liquid phase segment, the outlet of the liquid return valve is connected to the inlet of the circulation pump through the second liquid phase segment, and the outlet of the circulation pump is connected to the liquid inlet of the low-temperature liquid storage tank through the third liquid phase segment.

[0017] Optionally, the first gas phase pipeline includes a first gas phase segment, a second gas phase segment and a third gas phase segment, the air outlet of the low-temperature liquid storage tank is connected to the air inlet of the low-temperature fan through the first gas phase segment, the air outlet of the low-temperature fan is connected to the inlet of the return air valve through the second gas phase segment, and the outlet of the return air valve is connected to the air inlet of the refrigeration module through the third gas phase segment.

[0018] Optionally, the air outlet of the liquid replenishing tank is connected to the air inlet of the refrigeration module through a second gas phase pipeline, and an air inlet valve is provided on the second gas phase pipeline, and the air inlet valve is used to control the opening and closing of the second gas phase pipeline.

[0019] According to another aspect of the present invention, the present invention further provides a control method for a low-temperature refrigeration system, which is used to control the operation of the low-temperature refrigeration system described in any of the above technical solutions, and the control method for the low-temperature refrigeration system comprises:

[0020] Start the refrigeration module, open the air return valve, close the liquid return valve and the liquid replenishment valve, and obtain the real-time liquid level of the cryogenic liquid storage tank;

[0021] Controlling the refrigeration module to operate in a condensation liquid replenishment mode to condense the vaporized steam in the cryogenic liquid storage tank and then transport it back to the cryogenic liquid storage tank;

[0022] During the operation of the refrigeration module in a condensing and refilling mode, if the real-time liquid level of the cryogenic liquid storage tank is lower than the lowest set liquid level, the refill valve and the drain valve of the cryogenic liquid storage tank are controlled to open, and cryogenic liquid is transported into the cryogenic liquid storage tank through the refill tank until the liquid level in the cryogenic liquid storage tank rises to the highest set liquid level, and then the refill valve is closed.

[0023] Optionally, the specific steps of controlling the refrigeration module to operate in a condensation and liquid replenishment mode include:

[0024] Obtaining the real-time liquid level of the condensate in the refrigeration module;

[0025] When the real-time liquid level of the condensate rises to a first set liquid level, the liquid return valve is opened, and liquid is replenished into the low-temperature liquid storage tank through the refrigeration module, until the real-time liquid level of the condensate drops to a second set liquid level, and the liquid return valve is closed, and the second set liquid level is lower than the first set liquid level;

[0026] Repeat the above steps.

[0027] Optionally, while opening the liquid return valve, the air return valve is closed, the self-pressurizing valve is opened and the self-pressurizing device is started;

[0028] And / or, while opening the liquid return valve, start the circulation pump.

[0029] Optionally, when the air return valve is in an open state, the low-temperature blower is controlled to start;

[0030] And / or, when the liquid return valve is in a closed state, the air return valve is controlled to be opened, and when the liquid return valve is in an open state, the air return valve is controlled to be closed.

[0031] Optionally, one end of the second liquid phase pipeline is connected to the liquid outlet of the liquid replenishing tank, and the other end is connected to the first liquid phase pipeline;

[0032] When the liquid replenishing valve is opened to replenish liquid into the low-temperature liquid storage tank through the liquid replenishing tank, the liquid return valve is controlled to be closed.

[0033] The beneficial effects of the present invention are:

[0034] The present invention provides a low-temperature refrigeration system, including a cryogenic liquid storage tank, a refrigeration module and a liquid replenishing tank. The cryogenic liquid stored in the cryogenic liquid storage tank is used to cool down the superconducting power equipment. The cryogenic liquid evaporates into gas after heat exchange with the superconducting power equipment. The gas is transported to the refrigeration module and condensed into liquid, and then transported back to the cryogenic liquid storage tank again, so that the refrigeration module can maintain the total amount of cryogenic liquid in the cryogenic liquid storage tank while refrigerating. When the total amount of cryogenic liquid in the cryogenic liquid storage tank is insufficient due to a refrigeration module failure, maintenance or insufficient refrigeration capacity, the cryogenic liquid can be replenished into the cryogenic liquid storage tank through the liquid replenishing tank. Such a configuration can effectively ensure the immersion conditions of the superconducting power equipment in the cryogenic liquid storage tank, and does not require frequent use of the liquid replenishing tank for liquid replenishment, saving labor costs and facilitating automatic operation.

[0035] The present invention also provides a control method for a low-temperature refrigeration system. The control method for a low-temperature refrigeration system can be used to control the low-temperature refrigeration system to provide a reliable low-temperature environment for superconducting power equipment, thereby improving the reliability of the operation of the superconducting power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0037] Figure 1 A schematic diagram of the structure of a low-temperature refrigeration system provided in Embodiment 1 of the present invention;

[0038] Figure 2 A schematic diagram of the structure of a low-temperature refrigeration system provided in Embodiment 2 of the present invention;

[0039] Figure 3 A schematic diagram of the structure of a low-temperature refrigeration system provided in Embodiment 3 of the present invention;

[0040] Figure 4 This is a flow chart of a control method for a low-temperature refrigeration system provided in Embodiment 4 of the present invention.

[0041] In the figure:

[0042] 1. Cryogenic liquid storage tank; 2. Refrigeration module; 21. Refrigeration box; 22. Refrigeration machine cold head; 23. Self-pressurizing valve; 24. Self-pressurizing device; 3. First gas phase pipeline; 31. First gas phase segment; 32. Second gas phase segment; 33. Third gas phase segment; 4. First liquid phase pipeline; 41. First liquid phase segment; 42. Second liquid phase segment; 43. Third liquid phase segment; 5. Return valve; 6. Return liquid valve; 7. Liquid replenishment tank; 8. Second liquid phase pipeline; 9. Liquid replenishment valve; 10. Circulation pump; 11. Second gas phase pipeline; 12. Inlet valve; 13. Cryogenic fan. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0047] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0050] Embodiment 1

[0051] The present embodiment provides a low-temperature refrigeration system, which combines two replenishment methods: replenishment of the refrigeration module and replenishment of the replenishment tank. It can effectively ensure the immersion conditions of the superconducting power equipment in the low-temperature liquid storage tank, and does not require frequent replenishment, thus saving labor costs and facilitating automated operation.

[0052] Specifically, Figure 1 As shown, the low-temperature refrigeration system includes a cryogenic liquid storage tank 1, a refrigeration module 2 and a liquid replenishment tank 7. Cryogenic liquid is stored in the cryogenic liquid storage tank 1, and the superconducting power device is immersed in the cryogenic liquid. The air inlet of the refrigeration module 2 is connected to the air outlet of the cryogenic liquid storage tank 1 through the first gas phase pipeline 3, and the liquid outlet of the refrigeration module 2 is connected to the liquid inlet of the cryogenic liquid storage tank 1 through the first liquid phase pipeline 4. The first gas phase pipeline 3 is provided with a return valve 5 for controlling its on and off, and the first liquid phase pipeline 4 is provided with a return valve 6 for controlling its on and off. Cryogenic liquid is stored in the liquid replenishment tank 7, and the liquid outlet of the liquid replenishment tank 7 is connected to the liquid inlet of the cryogenic liquid storage tank 1 through the second liquid phase pipeline 8, and the second liquid phase pipeline 8 is provided with a liquid replenishment valve 9 for controlling its on and off.

[0053] When the low-temperature refrigeration system is working, the refrigeration module 2 is started, the return valve 5 is opened, and the superconducting power equipment exchanges heat with the cryogenic liquid in the cryogenic liquid storage tank 1, so that part of the cryogenic liquid will be vaporized into steam, and the steam will enter the refrigeration module 2 through the first gas phase pipeline 3. The steam entering the refrigeration module 2 will be condensed into cryogenic liquid under the condensation effect of the refrigeration module 2. When the cryogenic liquid in the refrigeration module 2 reaches a certain liquid level, the return valve 6 is opened, and the cryogenic liquid in the refrigeration module 2 will return to the cryogenic liquid storage tank 1 through the return valve 6. That is, through the action of the refrigeration module 2, the temperature and total amount of the cryogenic liquid in the cryogenic liquid storage tank 1 can be kept constant, thereby improving the reliability of the cryogenic liquid storage tank 1 in cooling the superconducting power equipment.

[0054] When the refrigeration module 2 needs to be shut down for maintenance and cannot replenish the cryogenic liquid storage tank 1, resulting in insufficient total amount of cryogenic liquid in the cryogenic liquid storage tank 1, or the efficiency of the refrigeration module 2 is lower than the evaporation efficiency of the cryogenic liquid in the cryogenic liquid storage tank 1, resulting in insufficient total amount of cryogenic liquid in the cryogenic liquid storage tank 1, the refilling valve 9 can be opened to allow the cryogenic liquid in the refilling tank 7 to flow into the cryogenic liquid storage tank 1 to replenish the cryogenic liquid in the cryogenic liquid storage tank 1. This method of combining the refilling tank 7 with the refrigeration module 2 to replenish the cryogenic liquid storage tank 1 can effectively ensure the immersion conditions of the superconducting power equipment in the cryogenic liquid storage tank 1, and there is no need to frequently use the refilling tank 7 for refilling, saving labor costs and facilitating automatic operation.

[0055] Optionally, in this embodiment, one end of the second liquid phase pipeline 8 is connected to the liquid outlet of the liquid replenishing tank 7, and the other end is connected to the first liquid phase pipeline 4. This arrangement can simplify the pipeline layout of the low temperature refrigeration system and reduce the pipeline layout cost.

[0056] Further, see Figure 1 The refrigeration module 2 includes a refrigeration box 21, a refrigerator cold head 22, a self-boosting valve 23 and a self-boosting device 24. Among them, the first air inlet of the refrigeration box 21 is connected to the first gas phase pipeline 3, and the first liquid outlet of the refrigeration box 21 is connected to the first liquid phase pipeline 4. The refrigerator cold head 22 is arranged in the refrigeration box 21, and is used to condense the steam in the refrigeration box 21 into a low-temperature liquid. The inlet of the self-boosting valve 23 is connected to the second liquid outlet of the refrigeration box 21, the outlet of the self-boosting valve 23 is connected to the boost input end of the self-boosting device 24, the boost output end of the self-boosting device 24 is connected to the second air inlet of the refrigeration box 21, and the self-boosting device 24 vaporizes the input low-temperature liquid and outputs it. The self-boosting device 24 can increase the pressure in the refrigeration box 21, so that the low-temperature liquid condensed in the refrigeration box 21 can quickly flow back to the low-temperature liquid storage tank 1 to increase the liquid replenishment speed.

[0057] Optionally, the self-pressurizing device 24 may be a self-pressurizing carburetor.

[0058] Optionally, the refrigeration module 2 may also be a GM refrigerator.

[0059] Embodiment 2

[0060] This embodiment provides a low-temperature refrigeration system, which is substantially the same in structure as the first embodiment, and is only improved on the basis of the first embodiment. Therefore, only the differences between the two are described here, and the same structures of this embodiment and the first embodiment are not repeated here.

[0061] In this embodiment, the technical features that are identical or corresponding to those in the first embodiment are marked with the same reference numerals.

[0062] Specifically, Figure 2 As shown, in this embodiment, the low-temperature refrigeration system also includes a circulation pump 10. Among them, the first liquid phase pipeline 4 includes a first liquid phase segment 41, a second liquid phase segment 42 and a third liquid phase segment 43. The liquid outlet of the refrigeration module 2 is connected to the inlet of the liquid return valve 6 through the first liquid phase segment 41, the outlet of the liquid return valve 6 is connected to the inlet of the circulation pump 10 through the second liquid phase segment 42, and the outlet of the circulation pump 10 is connected to the liquid inlet of the cryogenic liquid storage tank 1 through the third liquid phase segment 43. By providing the circulation pump 10, it is possible to provide power for the reflux of the cryogenic liquid in the refrigeration module 2, further improving the reflux speed of the cryogenic liquid.

[0063] Further, see Figure 2 , the low-temperature refrigeration system also includes a low-temperature fan 13. Among them, the first gas phase pipeline 3 includes a first gas phase segment 31, a second gas phase segment 32 and a third gas phase segment 33, the gas outlet of the low-temperature liquid storage tank 1 is connected to the air inlet of the low-temperature fan 13 through the first gas phase segment 31, the air outlet of the low-temperature fan 13 is connected to the inlet of the return valve 5 through the second gas phase segment 32, and the outlet of the return valve 5 is connected to the air inlet of the refrigeration module 2 through the third gas phase segment 33. By setting the low-temperature fan 13, it is possible to provide power for the flow of steam to speed up the efficiency of the steam in the low-temperature liquid storage tank 1 entering the refrigeration module 2. In addition, the low-temperature fan 13 can also make the pressure of the refrigeration module 2 greater than the pressure of the low-temperature liquid storage tank 1, thereby improving the liquefaction performance of the refrigeration module 2.

[0064] Embodiment 3

[0065] This embodiment provides a low-temperature refrigeration system, which is substantially the same in structure as the second embodiment, and is only improved on the basis of the second embodiment. Therefore, only the differences between the two are described here, and the same structures of this embodiment and the second embodiment are not repeated here.

[0066] In this embodiment, the technical features that are identical or corresponding to those in the second embodiment are marked with the same reference numerals.

[0067] Specifically, Figure 3 As shown, in this embodiment, the low-temperature refrigeration system further includes a second gas phase pipeline 11. Specifically, the gas outlet of the liquid replenishing tank 7 is connected to the gas inlet of the refrigeration module 2 through the second gas phase pipeline 11, and an air intake valve 12 is provided on the second gas phase pipeline 11, and the air intake valve 12 is used to control the on-off of the second gas phase pipeline 11. By providing the second gas phase pipeline 11, the steam in the liquid replenishing tank 7 can enter the refrigeration module 2, and after being liquefied by the refrigeration module 2, it is used to replenish the liquid for the low-temperature liquid storage tank 1, thereby avoiding the waste of the low-temperature liquid in the liquid replenishing tank 7 due to vaporization.

[0068] Embodiment 4

[0069] This embodiment provides a control method for a low-temperature refrigeration system, which is used to control the operation of the low-temperature refrigeration system provided in Embodiment 1, Embodiment 2 or Embodiment 3. The control method for a low-temperature refrigeration system can control the low-temperature refrigeration system to provide a reliable low-temperature environment for a superconducting power device, thereby improving the reliability of the operation of the superconducting power device.

[0070] Specifically, Figure 4 As shown, the control method of the low temperature refrigeration system includes:

[0071] S100, start the refrigeration module 2, open the air return valve 5, close the liquid return valve 6 and the liquid replenishment valve 9, and obtain the real-time liquid level of the cryogenic liquid storage tank 1;

[0072] S200, controlling the refrigeration module 2 to operate in a condensation liquid replenishment mode, so as to condense the vaporized steam in the cryogenic liquid storage tank 1 and transport it back to the cryogenic liquid storage tank 1;

[0073] When the refrigeration module 2 is operating in a condensation and refilling mode, if the real-time liquid level of the cryogenic liquid storage tank 1 is lower than the minimum set liquid level, the refilling valve 9 and the drain valve of the cryogenic liquid storage tank 1 are controlled to open, and cryogenic liquid is transported into the cryogenic liquid storage tank 1 through the refilling tank 7 until the liquid level in the cryogenic liquid storage tank 1 rises to the maximum set liquid level, and then the refilling valve 9 is closed.

[0074] The control method of the low-temperature refrigeration system is used to control the operation of the above-mentioned low-temperature refrigeration system, which can realize the combination of the refilling of the refrigeration module 2 and the refilling of the refilling tank 7, so that when the refrigeration capacity of the refrigeration module 2 is difficult to meet the refilling demand of the low-temperature liquid storage tank 1, or when the refrigeration module 2 stops working due to a failure, the refilling tank 7 can still ensure that the low-temperature liquid storage tank 1 provides reliable immersion conditions for the superconducting power equipment, effectively reducing the number of shutdowns of the superconducting power equipment. In addition, the combination of the refilling of the refrigeration module 2 and the refilling of the refilling tank 7 ensures that the refilling of the refilling tank 7 will only be started under extreme working conditions, effectively avoiding frequent refilling of the refilling tank 7, facilitating automatic operation, and saving labor costs.

[0075] It can be understood that when the liquid level in the cryogenic liquid storage tank 1 is lower than the minimum liquid level, it indicates that if the liquid level continues to drop, the superconducting power device will not be able to be immersed in the cryogenic liquid.

[0076] Optionally, the real-time liquid level in the cryogenic liquid storage tank 1 may be monitored by placing a liquid level meter in the cryogenic liquid storage tank 1 .

[0077] Further, in a possible embodiment, one end of the second liquid phase pipeline 8 is connected to the liquid outlet of the liquid replenishment tank 7, and the other end is connected to the first liquid phase pipeline 4. Since one end of the first liquid phase pipeline 4 is connected to the liquid inlet of the cryogenic liquid storage tank 1, such an arrangement can simplify the pipeline layout and save pipeline costs while ensuring that the liquid replenishment tank 7 can be connected to the cryogenic liquid storage tank 1 through the second liquid phase pipeline 8 and the first liquid phase pipeline 4. Under this structure, when the liquid replenishment valve 9 is opened to replenish liquid into the cryogenic liquid storage tank 1 through the liquid replenishment tank 7, it is necessary to control the liquid return valve 6 to be closed to prevent the cryogenic liquid in the liquid replenishment tank 7 from entering the refrigeration module 2 through the first liquid phase pipeline 4 and affecting the liquid replenishment speed.

[0078] Furthermore, the specific steps of controlling the refrigeration module 2 to operate in a condensation liquid replenishment mode include:

[0079] S210, obtaining the real-time liquid level of the condensate in the refrigeration module 2;

[0080] Optionally, the real-time liquid level of the condensate in the refrigeration module 2 may be monitored by providing a liquid level meter in the refrigeration module 2 .

[0081] S220, when the real-time liquid level of the condensate rises to the first set liquid level, the liquid return valve 6 is opened, and liquid is replenished into the low-temperature liquid storage tank 1 through the refrigeration module 2, until the real-time liquid level of the condensate drops to the second set liquid level, and the liquid return valve 6 is closed, and the second set liquid level is lower than the first set liquid level;

[0082] S230. Repeat steps S210-S220.

[0083] Optionally, in a possible embodiment, the refrigeration module 2 includes a refrigeration box 21, a refrigerator cold head 22, a self-pressurizing valve 23 and a self-pressurizing device 24. Therefore, when the liquid return valve 6 is opened to replenish liquid into the cryogenic liquid storage tank 1, the gas return valve 5 can be controlled to be closed, and the self-pressurizing valve 23 is opened and the self-pressurizing device 24 is started, and the air pressure in the refrigeration box 21 is increased by the self-pressurizing device 24, so that the condensate in the refrigeration box 21 is pressed into the cryogenic liquid storage tank 1 through the pressure difference.

[0084] It is understandable that closing the return valve 5 can prevent the gas in the refrigeration box 21 from flowing back into the cryogenic liquid storage tank 1 through the first gas phase pipeline 3 due to excessive pressure in the refrigeration box 21 .

[0085] Optionally, in another possible embodiment, a circulation pump 10 is provided on the first liquid phase pipeline 4. In this structure, when the liquid return valve 6 is opened to replenish liquid into the cryogenic liquid storage tank 1, the circulation pump 10 can be controlled to start, and the condensate in the first liquid phase pipeline 4 is driven to quickly flow back into the cryogenic liquid storage tank 1 by the circulation pump 10.

[0086] Of course, for the solution of providing both the self-pressurizing device 24 and the circulating pump 10, the self-pressurizing device 24 and the circulating pump 10 can also be started at the same time, and can be set according to the specific situation. This application does not make any specific limitations.

[0087] Optionally, in other possible embodiments, a low-temperature fan 13 is provided on the first gas phase pipeline 3. Therefore, when the return valve 5 is in an open state, the low-temperature fan 13 is controlled to start, which can increase the speed at which the steam in the low-temperature liquid storage tank 1 enters the refrigeration module 2. Of course, when the return valve 5 is in a closed state, the low-temperature fan 13 can be turned off to save energy.

[0088] Optionally, a second gas phase pipeline 11 may be provided to connect the gas outlet of the liquid replenishing tank 7 and the gas inlet of the refrigeration module 2, so as to condense and recover the steam in the liquid replenishing tank 7 through the refrigeration module 2. In this configuration, when the liquid return valve 6 is in a closed state, the gas return valve 5 on the second gas phase pipeline 11 is controlled to be opened; when the liquid return valve 6 is in an open state, the gas return valve 5 is controlled to be closed.

[0089] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A low temperature refrigeration system, characterized in that: include: A cryogenic liquid storage tank (1), wherein the cryogenic liquid is stored in the cryogenic liquid storage tank (1), and the superconducting power device is immersed in the cryogenic liquid; A refrigeration module (2), wherein the air inlet of the refrigeration module (2) is connected to the air outlet of the cryogenic liquid storage tank (1) via a first gas phase pipeline (3), the liquid outlet of the refrigeration module (2) is connected to the liquid inlet of the cryogenic liquid storage tank (1) via a first liquid phase pipeline (4), the first gas phase pipeline (3) is provided with an air return valve (5) for controlling the on-off thereof, and the first liquid phase pipeline (4) is provided with a liquid return valve (6) for controlling the on-off thereof; A liquid replenishment tank (7), wherein low-temperature liquid is stored in the liquid replenishment tank (7), a liquid outlet of the liquid replenishment tank (7) is connected to a liquid inlet of the low-temperature liquid storage tank (1) via a second liquid phase pipeline (8), and a liquid replenishment valve (9) for controlling the on-off of the second liquid phase pipeline (8) is provided on the second liquid phase pipeline (8).

2. The low temperature refrigeration system according to claim 1, characterized in that: The refrigeration module (2) comprises: A refrigeration box (21), wherein a first air inlet of the refrigeration box (21) is in communication with the first gas phase pipeline (3), and a first liquid outlet of the refrigeration box (21) is in communication with the first liquid phase pipeline (4); A refrigerator cold head (22) is arranged in the refrigeration box (21); A self-pressurizing valve (23), wherein the inlet of the self-pressurizing valve (23) is connected to the second liquid outlet of the refrigerating box (21); A self-pressurizing device (24), wherein the outlet of the self-pressurizing valve (23) is connected to the pressurizing input end of the self-pressurizing device (24), and the pressurizing output end of the self-pressurizing device (24) is connected to the second air inlet of the refrigeration box (21), and the self-pressurizing device (24) vaporizes the input low-temperature liquid and outputs it.

3. The low temperature refrigeration system according to claim 1, characterized in that: The first liquid phase pipeline (4) comprises a first liquid phase segment (41), a second liquid phase segment (42) and a third liquid phase segment (43); the liquid outlet of the refrigeration module (2) is connected to the inlet of the liquid return valve (6) through the first liquid phase segment (41); the outlet of the liquid return valve (6) is connected to the inlet of the circulation pump (10) through the second liquid phase segment (42); and the outlet of the circulation pump (10) is connected to the liquid inlet of the low-temperature liquid storage tank (1) through the third liquid phase segment (43).

4. The low temperature refrigeration system according to claim 1, characterized in that: The first gas phase pipeline (3) includes a first gas phase segment (31), a second gas phase segment (32) and a third gas phase segment (33); the gas outlet of the low-temperature liquid storage tank (1) is connected to the gas inlet of the low-temperature fan (13) through the first gas phase segment (31); the gas outlet of the low-temperature fan (13) is connected to the inlet of the return valve (5) through the second gas phase segment (32); and the outlet of the return valve (5) is connected to the gas inlet of the refrigeration module (2) through the third gas phase segment (33).

5. The low temperature refrigeration system according to any one of claims 1 to 4, characterized in that: The air outlet of the liquid replenishing tank (7) is connected to the air inlet of the refrigeration module (2) via a second gas phase pipeline (11); an air inlet valve (12) is provided on the second gas phase pipeline (11); and the air inlet valve (12) is used to control the opening and closing of the second gas phase pipeline (11).

6. A method for controlling a low temperature refrigeration system, for controlling the operation of the low temperature refrigeration system according to any one of claims 1 to 5, characterized in that: The control method of the low temperature refrigeration system comprises: Start the refrigeration module (2), open the air return valve (5), close the liquid return valve (6) and the liquid replenishment valve (9), and simultaneously obtain the real-time liquid level of the cryogenic liquid storage tank (1); Controlling the refrigeration module (2) to operate in a condensation liquid replenishment mode, so as to condense the vaporized steam in the cryogenic liquid storage tank (1) and transport it back into the cryogenic liquid storage tank (1); During the operation of the refrigeration module (2) in a condensation and refilling mode, if the real-time liquid level of the cryogenic liquid storage tank (1) is lower than the lowest set liquid level, the refilling valve (9) and the drain valve of the cryogenic liquid storage tank (1) are controlled to open, and cryogenic liquid is transported into the cryogenic liquid storage tank (1) through the refilling tank (7) until the liquid level in the cryogenic liquid storage tank (1) rises to the highest set liquid level, and then the refilling valve (9) is closed.

7. The control method of the low temperature refrigeration system according to claim 6, characterized in that: The specific steps of controlling the refrigeration module (2) to operate in a condensation and liquid replenishment mode include: Obtaining the real-time liquid level of the condensate in the refrigeration module (2); When the real-time liquid level of the condensate rises to a first set liquid level, the liquid return valve (6) is opened, and liquid is replenished into the low-temperature liquid storage tank (1) through the refrigeration module (2), until the real-time liquid level of the condensate drops to a second set liquid level, and the liquid return valve (6) is closed, and the second set liquid level is lower than the first set liquid level; Repeat the above steps.

8. The control method of the low temperature refrigeration system according to claim 7, characterized in that: While opening the liquid return valve (6), closing the air return valve (5), opening the self-pressurizing valve (23) and starting the self-pressurizing device (24); And / or, while opening the liquid return valve (6), the circulation pump (10) is started.

9. The control method of the low temperature refrigeration system according to claim 7, characterized in that: When the air return valve (5) is in an open state, the low-temperature fan (13) is controlled to start; And / or, when the liquid return valve (6) is in a closed state, the air return valve (5) is controlled to be opened, and when the liquid return valve (6) is in an open state, the air return valve (5) is controlled to be closed.

10. The control method of the low temperature refrigeration system according to claim 6, characterized in that: One end of the second liquid phase pipeline (8) is in communication with the liquid outlet of the liquid replenishing tank (7), and the other end is in communication with the first liquid phase pipeline (4); When the liquid replenishing valve (9) is opened to replenish liquid into the low-temperature liquid storage tank (1) through the liquid replenishing tank (7), the liquid return valve (6) is controlled to be closed.

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