A liquid helium container precooling and filling system

Abstract

The liquid helium container precooling and filling system provided in the present application includes two precooling schemes of liquid nitrogen precooling followed by liquid helium precooling and helium liquefier precooling, which reduces the amount of liquid helium used in the precooling process and controls a reasonable cooling rate, and integrates the two precooling schemes into a precooling and filling system to achieve reliable, efficient and economical precooling and filling of liquid helium containers.

Description

Technical Field

[0001] The present application relates to the field of cryogenic containers, and in particular to a liquid helium container precooling and filling system. Background Art

[0002] At present, no special device for precooling and filling liquid helium containers has been investigated. In most cases, liquid helium is used to directly fill the liquid helium container. During the filling process, the liquid helium container with a high temperature is cooled down by the cooling of the liquid helium. The defects of this method are mainly the waste of liquid helium (helium is difficult to liquefy, and it is relatively wasteful to use liquid helium in the precooling process) and the potential risk of damage to the structure by thermal stress during the cooling process (excessive flow of precooled liquid helium will cause the liquid helium container to cool down quickly, and the thermal stress caused by the thermal expansion coefficient of the material is large). The present invention proposes two precooling schemes of precooling with liquid nitrogen first and then with liquid helium and precooling with a helium liquefier, which reduce the amount of liquid helium used in the precooling process and control the reasonable cooling rate, and integrate the two precooling schemes into a precooling and filling system.

[0003] Compared with the storage and transportation methods of high-pressure helium, liquid helium has a higher storage and transportation density and better economy, and is one of the development trends of large-scale helium resource storage and transportation. The precooling and filling of liquid helium containers is an indispensable operation link in the storage and transportation of helium resources. Reliable, efficient and economical precooling and filling schemes have important application value. In most cases, liquid helium is directly filled into the liquid helium container. During the filling process, the liquid helium container with a higher temperature is cooled down by the cooling of the liquid helium. The defects of this method are mainly the waste of liquid helium (helium is difficult to liquefy, and it is relatively wasteful to use liquid helium in the precooling process) and the potential risk of damage to the structure due to thermal stress during the cooling process (excessive flow of precooled liquid helium will cause the liquid helium container to cool down quickly, and the thermal stress caused by the thermal expansion coefficient of the material is large). Summary of the invention

[0004] In view of this, it is necessary to provide a reliable, efficient and economical liquid helium container precooling and filling system to address the technical defects of the prior art, such as the waste of liquid helium and the potential risk of damage to the structure caused by thermal stress during the cooling process.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] The present application provides a liquid helium container precooling and filling system, including a liquid nitrogen precooling and then liquid helium precooling and filling unit and / or a helium liquefier precooling and filling unit, wherein:

[0007] The liquid nitrogen pre-cooling and then liquid helium pre-cooling and filling unit comprises: a liquid nitrogen storage tank 1, a helium storage tank 2, a liquid helium container 1 3, a helium purification and recovery unit 6, a liquid helium container 2 7 and a vacuum pump 8. The liquid nitrogen storage tank 1 transfers liquid nitrogen to the liquid helium container 2 7 through a first pipeline L1. The evaporated nitrogen in the liquid helium container 2 7 is reheated to room temperature through the reheating air heater 9 through a second pipeline L2, and is discharged into the atmosphere after being measured by the flow meter 10. After the reading of the flow meter 10 tends to be stable, the next liquid nitrogen transfer is started until the temperature sensor T02 located on the second pipeline L2 reaches the temperature of the liquid nitrogen temperature zone, and the liquid nitrogen pre-cooling is completed; when the liquid nitrogen pre-cooling is completed, the nitrogen storage tank 11 fills the liquid helium container 2 7 with nitrogen through the third pipeline L3 and the flow meter 12. When the nitrogen flow rate flowing through the flow meter 10 is equal to the nitrogen flow rate flowing through the flow meter 12, it indicates that there is no more liquid nitrogen gasification in the liquid helium container 2 7; the vacuum pump 8 is connected to the second pipeline L4 through the fourth pipeline L5. Connect the rewarming air heater 9, start the vacuum pump 8, evacuate the liquid helium container 2 7, and when the vacuum gauge P03 on the fourth pipeline L4 reaches 1Pa, turn off the evacuation, and the helium in the helium storage tank 2 is filled into the liquid helium container 2 7 through the fifth pipeline L5 to complete the gas replacement; after the gas replacement operation is completed, the helium in the helium storage tank 2 is pressurized by charging the liquid helium container 3 with helium through the sixth pipeline L6 to ensure that the liquid helium container 3 and the liquid helium container 2 7 maintain a certain pressure difference, so that the liquid helium in the liquid helium container 3 is filled into the liquid helium container 2 7 through the seventh pipeline L7, and the helium evaporated from the liquid helium container 2 7 enters the helium purification and recovery unit 6 for purification and storage through the eighth pipeline L8; the transfer process should monitor the reading of the pressure sensor P02 in the liquid helium container 2 7 throughout the whole process, and timely control the regulating valve V02 to adjust the transfer flow rate to prevent the liquid helium container from overpressure until it is filled to the rated filling volume, and the liquid helium filling is completed;

[0008] The helium liquefier precooling and filling unit comprises: a helium liquefier 4 and a liquid helium container 2 7. The helium liquefier 4 is turned on, and the helium liquefier 4 starts to refrigerate and cool down. The cold helium gas produced enters the liquid helium container 2 7 through the 9th pipeline L9 to cool down the liquid helium container 2 7; the liquid helium container 2 7 is cooled down together with the helium liquefier 4, and the precooling ends when the temperature drops to the point where the helium liquefier 4 produces liquid helium; then the helium liquefier 4 starts to produce liquid helium, and the produced liquid helium is filled into the liquid helium container 2 7 until it is filled to the rated filling amount, and the liquid helium filling is completed, and the helium gas discharged from the liquid helium container 2 7 returns to the helium liquefier 4.

[0009] In some embodiments, a regulating valve V01 is further installed on the first pipeline L1, and the regulating valve V01 is used to control the flow rate of the transferred liquid nitrogen.

[0010] In some of the embodiments, the liquid helium container 27 is also connected to a pressure sensor P02.

[0011] In some embodiments, a regulating valve V09 is further provided on the second pipeline L2, and the regulating valve V09 is used to control the flow rate of nitrogen discharged into the atmosphere after being measured by the flow meter 10.

[0012] In some of the embodiments, a regulating valve V10 is further provided on the third pipeline L3 , and the regulating valve V10 is used to control the flow rate of nitrogen passing through the flowmeter 12 .

[0013] In some embodiments, the fourth pipeline L4 is further provided with a vacuum plug valve V08, and the vacuum plug valve V08 is opened or closed to achieve vacuum processing of the liquid helium container 2 7.

[0014] In some of the embodiments, a regulating valve V06 is further provided on the fifth pipeline L5, and the regulating valve V06 can adjust the flow rate of the helium in the helium storage tank 2 into the liquid helium container 7.

[0015] In some of the embodiments, a regulating valve V02 is further provided on the sixth pipeline L6, and the helium in the helium storage tank 2 is pressurized by filling the liquid helium container 3 with helium through the regulating valve V02 to ensure that a certain pressure difference is maintained between the liquid helium container 1 3 and the liquid helium container 2 7.

[0016] In some of the embodiments, a regulating valve V03 is further provided on the seventh pipeline L7, and the regulating valve V03 can adjust the flow rate of liquid helium filling the liquid helium container 2 7 through the liquid helium container 1 3 .

[0017] In some of the embodiments, the eighth pipeline L8 is further provided with an electric heater 5 and a regulating valve V07, the electric heater 5 is used to heat the low-temperature helium discharged from the liquid helium container 2 7, and the regulating valve V07 is used to control the flow of the helium evaporated from the liquid helium container 2 7 entering the helium purification and recovery unit 6.

[0018] In some of the embodiments, a regulating valve V05 is further provided on the ninth pipeline L9, and the regulating valve V05 is used to control the flow rate of the cold helium gas generated by the helium liquefier 4 when it starts to refrigerate and cool down and enter the liquid helium container 2 7.

[0019] This application adopts the above technical solution, and its beneficial effects are as follows:

[0020] The liquid helium container precooling and filling system provided in the present application includes two precooling schemes of liquid nitrogen precooling followed by liquid helium precooling and helium liquefier precooling, which reduces the amount of liquid helium used in the precooling process and controls a reasonable cooling rate, and integrates the two precooling schemes into a precooling and filling system to achieve reliable, efficient and economical precooling and filling of liquid helium containers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A schematic structural diagram of a liquid helium container precooling and filling system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] Embodiments of the present application are described in detail below, and examples of the embodiments 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 intended to be used to explain the present application, and should not be construed as limiting the present application.

[0024] In the description of the present application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] See also Figure 1, which is a structural schematic diagram of the liquid helium container precooling and filling system provided in this embodiment, includes: a liquid nitrogen precooling and then liquid helium precooling and filling unit and / or a helium liquefier precooling and filling unit. The specific implementation method of each unit is described in detail below.

[0028] The liquid nitrogen precooling and then liquid helium precooling and filling unit comprises: a liquid nitrogen storage tank 1, a helium storage tank 2, a liquid helium container 1 3, a helium purification and recovery unit 6, a liquid helium container 2 7 and a vacuum pump 8. The liquid nitrogen storage tank 1 transfers liquid nitrogen to the liquid helium container 2 7 through a first pipeline L1. The evaporated nitrogen in the liquid helium container 2 7 is reheated to room temperature through the second pipeline L2 and the reheating air heater 9, and is discharged into the atmosphere after being measured by the flow meter 10. After the reading of the flow meter 10 tends to be stable, the next step is started. The liquid nitrogen is transferred again until the temperature sensor T02 located on the second pipeline L2 reaches the temperature of the liquid nitrogen temperature zone (about 80K), and the liquid nitrogen pre-cooling is completed; when the liquid nitrogen pre-cooling is completed, the nitrogen storage tank 11 is filled with nitrogen through the third pipeline L3 and the flow meter 12 to the liquid helium container 2 7. When the nitrogen flow rate flowing through the flow meter 10 is equal to the nitrogen flow rate flowing through the flow meter 12, it indicates that there is no more liquid nitrogen gasification in the liquid helium container 2 7, and the residual liquid nitrogen is cleared; the vacuum pump 8 is connected to the rewarming air heater 9 through the fourth pipeline L4, and the vacuum pump 8 is started to evacuate the liquid helium container 2 7. When the vacuum gauge P03 located on the fourth pipeline L4 shows 1Pa, the vacuum pump is turned off, and the helium in the helium storage tank 2 is filled into the liquid helium container 2 7 through the fifth pipeline L5 to complete the gas replacement, and the gas replacement is about 2 to 3 times; after the gas replacement operation is completed, the helium in the helium storage tank 2 is charged with helium to the liquid helium container 3 through the sixth pipeline L6 to increase the pressure, so as to ensure that the liquid A certain pressure difference is maintained between the helium container 1-3 and the liquid helium container 2-7, so that the liquid helium in the liquid helium container 1-3 is filled into the liquid helium container 2-7 through the seventh pipeline L7, and the helium evaporated from the liquid helium container 2-7 enters the helium purification and recovery unit 6 for purification and storage through the eighth pipeline L8; the transfer process should monitor the indication of the pressure sensor P02 located in the liquid helium container 2-7 throughout the whole process, and timely control the regulating valve V02 to adjust the transfer flow rate to prevent the liquid helium container from overpressure, until it is filled to the rated filling volume, and the liquid helium filling is completed.

[0029] The helium liquefier precooling and filling unit comprises: a helium liquefier 4 and a liquid helium container 2 7. The helium liquefier 4 is turned on, and the helium liquefier 4 starts to refrigerate and cool down. The cold helium gas produced enters the liquid helium container 2 7 through the 9th pipeline L9 to cool down the liquid helium container 2 7; the liquid helium container 2 7 is cooled down together with the helium liquefier 4, and the precooling ends when the temperature drops to the point where the helium liquefier 4 produces liquid helium; then the helium liquefier 4 starts to produce liquid helium, and the produced liquid helium is filled into the liquid helium container 2 7 until it is filled to the rated filling amount, and the liquid helium filling is completed, and the helium gas discharged from the liquid helium container 2 7 returns to the helium liquefier 4.

[0030] In some embodiments, a regulating valve V01 is further installed on the first pipeline L1, and the regulating valve V01 is used to control the flow rate of the transferred liquid nitrogen.

[0031] In some of the embodiments, the liquid helium container 27 is also connected to a pressure sensor P02.

[0032] In some embodiments, a regulating valve V09 is further provided on the second pipeline L2, and the regulating valve V09 is used to control the flow rate of nitrogen discharged into the atmosphere after being measured by the flow meter 10.

[0033] In some of the embodiments, a regulating valve V10 is further provided on the third pipeline L3 , and the regulating valve V10 is used to control the flow rate of nitrogen passing through the flowmeter 12 .

[0034] In some embodiments, the fourth pipeline L4 is further provided with a vacuum plug valve V08, and the vacuum plug valve V08 is opened or closed to achieve vacuum processing of the liquid helium container 2 7.

[0035] In some of the embodiments, a regulating valve V06 is further provided on the fifth pipeline L5, and the regulating valve V06 can adjust the flow rate of the helium in the helium storage tank 2 into the liquid helium container 7.

[0036] In some of the embodiments, a regulating valve V02 is further provided on the sixth pipeline L6, and the helium in the helium storage tank 2 is pressurized by filling the liquid helium container 3 with helium through the regulating valve V02 to ensure that a certain pressure difference is maintained between the liquid helium container 1 3 and the liquid helium container 2 7.

[0037] In some of the embodiments, a regulating valve V03 is further provided on the seventh pipeline L7, and the regulating valve V03 can adjust the flow rate of liquid helium filling the liquid helium container 2 7 through the liquid helium container 1 3 .

[0038] In some of the embodiments, the eighth pipeline L8 is further provided with an electric heater 5 and a regulating valve V07, the electric heater 5 is used to heat the low-temperature helium discharged from the liquid helium container 2 7, and the regulating valve V07 is used to control the flow of the helium evaporated from the liquid helium container 2 7 entering the helium purification and recovery unit 6.

[0039] In some of the embodiments, a regulating valve V05 is further provided on the ninth pipeline L9, and the regulating valve V05 is used to control the flow rate of the cold helium gas generated by the helium liquefier 4 when it starts to refrigerate and cool down and enter the liquid helium container 2 7.

[0040] The liquid helium container precooling and filling system provided in Example 1 of the present application includes two precooling schemes of liquid nitrogen precooling followed by liquid helium precooling and helium liquefier precooling, which reduces the amount of liquid helium used in the precooling process and controls a reasonable cooling rate, and integrates the two precooling schemes into a precooling and filling system to achieve reliable, efficient and economical precooling and filling of liquid helium containers.

[0041] It can be understood that the technical features of the above-described embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A liquid helium container precooling and filling system, characterized in that: It includes a liquid nitrogen precooling and then liquid helium precooling and filling unit and / or a helium liquefier precooling and filling unit, wherein: The liquid nitrogen pre-cooling and then liquid helium pre-cooling and filling unit comprises: a liquid nitrogen storage tank (1), a helium storage tank (2), a liquid helium container (3), a helium purification and recovery unit (6), a liquid helium container (7) and a vacuum pump (8). The liquid nitrogen storage tank (1) transfers liquid nitrogen to the liquid helium container (7) through a first pipeline (L1). The evaporated nitrogen in the liquid helium container (7) is reheated to room temperature through a reheating air heater (9) through a second pipeline (L2) and then passes through a first flow meter (10). After metering, the atmosphere is discharged. When the reading of the first flow meter (10) tends to be stable, the next liquid nitrogen transfer is started until the temperature sensor (T02) located on the second pipeline (L2) reaches the temperature of the liquid nitrogen temperature zone, and the liquid nitrogen pre-cooling is completed. When the liquid nitrogen pre-cooling is completed, the nitrogen storage tank (11) is filled with nitrogen through the third pipeline (L3) and the second flow meter (12) into the second liquid helium container (7). When the nitrogen flow rate flowing through the flow meter (10) is equal to the nitrogen flow rate flowing through the second flow meter (12), it indicates that there is no more liquid nitrogen gasification in the second liquid helium container (7). The vacuum pump (8) is connected to the rewarming air heater (9) through the fourth pipeline (L4), and the vacuum pump (8) is started to evacuate the second liquid helium container (7). When the reading of the vacuum gauge (P03) located on the fourth pipeline (L4) reaches 1Pa, the evacuation is turned off, and the helium in the helium storage tank (2) is filled into the second liquid helium container (7) through the fifth pipeline (L5), completing the gas replacement. After the gas replacement operation is completed, the helium in the helium storage tank (2) is charged with helium to the liquid helium container (3) through the sixth pipeline (L6) to increase the pressure, ensuring that the liquid helium container (3) and the liquid helium container (7) maintain a certain pressure difference, so that the liquid helium in the liquid helium container (3) is charged into the liquid helium container (7) through the seventh pipeline (L7), and the helium evaporated from the liquid helium container (7) enters the helium purification and recovery unit (6) through the eighth pipeline (L8) for purification and storage; The helium liquefier precooling and filling unit comprises: a helium liquefier (4) and a second liquid helium container (7); the helium liquefier (4) is turned on, the helium liquefier (4) starts to cool down, and the cold helium gas produced enters the second liquid helium container (7) through a ninth pipeline (L9), thereby cooling the second liquid helium container (7); the second liquid helium container (7) is cooled down along with the cooling of the helium liquefier (4); when the temperature drops to the point where the helium liquefier (4) produces liquid helium, the precooling ends; then the helium liquefier (4) starts to produce liquid helium, and the produced liquid helium is filled into the second liquid helium container (7) until the liquid helium container (7) is filled to a rated filling amount, and the liquid helium filling is completed, and the helium gas discharged from the second liquid helium container (7) returns to the helium liquefier (4).

2. The liquid helium container precooling and filling system according to claim 1, characterized in that: The first pipeline (L1) is also provided with a regulating valve (V01), and the regulating valve (V01) is used to control the flow rate of the transferred liquid nitrogen.

3. The liquid helium container precooling and filling system according to claim 1, characterized in that: The second liquid helium container (7) is also connected to a pressure sensor (P02).

4. The liquid helium container precooling and filling system according to claim 1, characterized in that: The second pipeline (L2) is also provided with a regulating valve (V09), and the regulating valve (V09) is used to control the flow rate of nitrogen discharged into the atmosphere after being measured by the first flow meter (10).

5. The liquid helium container precooling and filling system according to claim 1, characterized in that: The third pipeline (L3) is also provided with a regulating valve (V10), and the regulating valve (V10) is used to control the flow rate of nitrogen passing through the second flow meter (12).

6. The liquid helium container precooling and filling system according to claim 1, characterized in that: The fourth pipeline (L4) is also provided with a vacuum plug valve (V08), and the vacuum plug valve (V08) is opened or closed to achieve vacuum treatment of the second liquid helium container (7).

7. The liquid helium container precooling and filling system according to claim 1, characterized in that: The fifth pipeline (L5) is also provided with a regulating valve (V06), and the regulating valve (V06) can adjust the flow rate of the helium in the helium storage tank (2) into the second liquid helium container (7).

8. The liquid helium container precooling and filling system according to claim 1, characterized in that: The sixth pipeline (L6) is also provided with a regulating valve (V02), and the helium in the helium storage tank (2) is fed into the liquid helium container one (3) through the regulating valve (V02) to increase the pressure of the helium, so as to ensure that a certain pressure difference is maintained between the liquid helium container one (3) and the liquid helium container two (7).

9. The liquid helium container precooling and filling system according to claim 1, characterized in that: The seventh pipeline (L7) is also provided with a regulating valve (V03), and the regulating valve (V03) can adjust the flow rate of liquid helium filled into the liquid helium container two (7) through the liquid helium container one (3).

10. The liquid helium container precooling and filling system according to claim 1, characterized in that: The eighth pipeline (L8) is also provided with an electric heater (5) and a regulating valve (V07), wherein the electric heater (5) is used to heat the low-temperature helium gas discharged from the second liquid helium container (7), and the regulating valve (V07) is used to control the flow rate of the helium gas evaporated from the second liquid helium container (7) entering the helium gas purification and recovery unit (6).

11. The liquid helium container precooling and filling system according to claim 1, characterized in that: The ninth pipeline (L9) is also provided with a regulating valve (V05), and the regulating valve (V05) is used to control the flow rate of the cold helium gas generated by the helium liquefier (4) when it starts to refrigerate and cool down and enter the second liquid helium container (7).

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