Liquid helium filling system and method

Abstract

According to high-purity helium filling, liquid helium of a liquid helium tank car enters a first vaporizer, after the purity of the helium is qualified, high-purity helium filling is conducted through a buffer tank, a first diaphragm compressor unit and a first filling row, and after high-purity helium filling is completed, residual helium of the first filling row enters the liquid helium tank car; liquid helium of a liquid helium tank car enters a liquid helium Dewar flask for liquid filling, air and the helium containing the liquid helium enter a second vaporizer to form industrial helium, the industrial helium enters an air bag, a second membrane compressor unit and a second filling row for filling and recycling, and after the purity of the helium is qualified, the helium is recycled. And high-purity helium is filled through the first filling row / the second filling row. According to the liquid helium filling system and method, the filling efficiency of liquid helium can be improved, and simultaneous filling of helium and liquid helium and recovery of industrial helium can be achieved in one device.

Description

Technical Field

[0001] The present application belongs to the technical field of liquid helium filling, and specifically relates to a liquid helium filling system and method. Background Art

[0002] Liquid helium is a low-temperature refrigerant widely used in scientific research, industrial production and medical fields. With the development of technology and the continuous expansion of application fields, the demand for liquid helium is also increasing. In order to facilitate the transportation and use of liquid helium, we fill liquid helium into cylinders or dewar tanks through a filling system. In the existing liquid helium filling system, liquid helium flows from the liquid helium tank truck into the liquid helium dewar flask through the filling pipeline. In the initial state of filling, the pressure difference between the liquid helium tank truck and the liquid helium dewar flask is too large, resulting in too fast flow rate and the generation of a large amount of low-purity industrial helium. Therefore, many researchers have tried to develop a method to solve the problem of helium waste caused by excessive pressure difference. For example, Chinese patent No. CN219756030U discloses a helium filling system, which is provided with safety ball valves at the liquid inlet and gas outlet ends of the dewar flask of the liquid helium filling pipeline. On the one hand, it is convenient to replace the dewar flask after the liquid helium filling is completed, and on the other hand, the safety ball valve can control the excessive pressure difference between the liquid helium tank truck and the dewar flask. However, helium molecules are relatively small and can easily pass through the gap in the ball valve and form leakage between the shell and the sphere. A Chinese patent with announcement number CN113324169A discloses a non-destructive helium filling process for a helium liquefier. In this process, a pressure relief valve is provided on the dewar to control the pressure difference between the liquid helium truck and the dewar. A pressure detection sensor, an alarm device, an emergency stop controller, a remote monitoring system, etc. are configured in the entire system. This process is not only technically complex, but also increases the filling cost and causes a large amount of helium to be wasted.

[0003] In addition, the compressors conventionally used for helium filling will reduce the purity of helium, and the low exhaust volume of low-pressure diaphragm compressors leads to low helium filling efficiency. The high intake pressure of high-pressure diaphragm compressors leads to the generation of a large amount of industrial helium in the initial stage of industrial helium recovery.

[0004] In summary, the prior art still has problems such as excessive pressure difference, serious helium waste, and low filling efficiency in the liquid helium filling system. Therefore, it is urgent to propose a liquid helium filling system and method to solve the problems in the prior art. Summary of the invention

[0005] In view of the problems of excessive pressure difference, serious helium waste, low filling efficiency, etc. in the liquid helium filling system in the prior art, the present application provides a liquid helium filling system and method, which are as follows:

[0006] The technical solution of this application is as follows:

[0007] On the one hand, the present application provides a liquid helium filling system, including a liquid helium filling unit, a high-purity helium filling unit and an industrial helium recovery unit;

[0008] The liquid helium filling unit comprises a liquid helium tank truck and a liquid helium Dewar flask, and the liquid helium tank truck and the liquid helium Dewar flask are connected to each other;

[0009] The high-purity helium filling unit comprises a first vaporizer, a buffer tank, a first diaphragm compressor unit and a first filling row which are sequentially connected along the flow direction of liquid helium; the first vaporizer is connected to a liquid helium tank truck;

[0010] The recovery unit comprises a second vaporizer, an air bag, a second diaphragm compressor unit and a second filling row which are connected in sequence along the flow direction of liquid nitrogen; the second vaporizer is connected to the liquid helium Dewar bottle.

[0011] Preferably, the liquid helium tank truck is provided with a first liquid helium outlet, a second liquid helium outlet and a high-purity helium inlet, the liquid helium dewar is provided with a liquid helium inlet and a liquid helium outlet, the first liquid helium outlet is communicated with the liquid helium inlet of the liquid helium dewar through a pipeline, the liquid helium outlet of the liquid helium dewar is communicated with the second vaporizer through a pipeline, the second vaporizer is communicated with the airbag through a pipeline, and the airbag is communicated with the second filling row through a pipeline; the second liquid helium outlet of the liquid helium tank truck is communicated with the first vaporizer through a pipeline, the first vaporizer is communicated with the buffer tank through a pipeline, the buffer tank is communicated with the first diaphragm compressor unit through a pipeline, the first diaphragm compressor unit is communicated with the first filling row through a pipeline, and the first filling row is communicated with the high-purity helium inlet of the liquid helium tank truck.

[0012] Preferably, a three-way element is provided on the pipeline between the second vaporizer and the airbag, one end of the three-way element is connected to the second vaporizer, one end is connected to the airbag, and one end is connected to the pipeline between the first vaporizer and the buffer tank. A helium purity analyzer is provided on the three-way element and the airbag pipeline for monitoring the purity of the helium.

[0013] Preferably, the first diaphragm compressor unit and the second diaphragm compressor unit are each composed of a low-pressure diaphragm compressor and a high-pressure diaphragm compressor connected in series.

[0014] Preferably, the first filling row is connected to the high-purity helium inlet of the liquid helium tank truck through a pipeline.

[0015] On the other hand, the present application provides a liquid helium filling method, comprising the following steps:

[0016] High-purity helium filling: Liquid helium in the liquid helium tank truck enters the first vaporizer. After the helium purity is qualified, high-purity helium is filled through the buffer tank, the first diaphragm compressor unit and the first filling row. After the high-purity helium filling is completed, the residual helium in the first filling row enters the liquid helium tank truck;

[0017] Liquid helium filling and helium recovery: Liquid helium in the liquid helium tank truck enters the liquid helium dewar for liquid filling, air and helium containing liquid helium enter the second vaporizer to form industrial helium, and industrial helium enters the air bag, the second membrane compressor unit and the second filling row for filling and recovery. After the helium purity is qualified, high-purity helium is filled through the first filling row / second filling row.

[0018] Preferably, the qualified helium has a purity greater than 99.999%.

[0019] The beneficial effects of this application are as follows:

[0020] The present application performs helium filling before filling liquid helium. The helium removes the low-pressure gas in the pipeline of the entire device, which can effectively reduce the initial pressure difference between the liquid helium tank truck and the liquid helium Dewar flask. By reducing the flow rate during the initial filling of liquid helium, the industrial helium generated during the filling process is reduced, thereby improving the filling efficiency of liquid helium.

[0021] The present application realizes effective separation of oil and gas by using a diaphragm compressor, thereby ensuring high purity of helium. The design of the diaphragm compressor unit reduces the intake pressure and reduces the amount of industrial helium generated. In addition, the displacement of the unit is increased, which improves the efficiency of helium filling.

[0022] The present application returns high-purity helium to the liquid helium tanker, speeds up the filling rate of liquid helium, and improves the efficiency and speed of the entire filling process.

[0023] The present application can simultaneously complete the filling of high-purity helium and liquid helium in the same set of equipment, and can also recycle industrial helium. The structure and layout of the filling system are simplified, making the entire process more efficient and convenient. For production units, this new technology not only provides a new filling method, but also improves production efficiency and operational convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings of the embodiments are briefly introduced below.

[0025] The drawings described below only relate to some embodiments of the present application and are not intended to limit the present application.

[0026] In the attached picture:

[0027] Figure 1 It is a schematic diagram of the process flow and method of an embodiment of the present application.

[0028] Reference numerals list

[0029] 1. Liquid helium tank truck; 2. Liquid helium dewar flask; 3. Second vaporizer; 4. Helium purity analyzer; 5. Air bag; 6. Second diaphragm compressor unit; 7. Second filling row; 8. First vaporizer; 9. Buffer tank; 10. First diaphragm compressor unit; 11. First filling row. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present application are described in detail below in combination with the preferred embodiments.

[0031] Device Embodiment

[0032] See also Figure 1 , this embodiment provides a liquid helium filling system, including a liquid helium filling unit, a high-purity helium filling unit and an industrial helium recovery unit;

[0033] In this embodiment, the liquid helium filling unit includes a liquid helium tank truck 1 for storing liquid helium and a liquid helium dewar flask 2 for filling liquid helium. The liquid helium tank truck 1 is provided with a first liquid helium outlet, and the liquid helium tank truck 1 is connected to the liquid helium inlet on the liquid helium dewar flask 2 through the first liquid helium outlet.

[0034] In this embodiment, the high-purity helium filling unit includes a first vaporizer 8, a buffer tank 9 for storing high-purity helium, a first diaphragm compressor unit 10 and a first filling row 11 which are connected in sequence along the flow direction of liquid helium; the first vaporizer 8 is connected to the buffer tank 9 through a pipeline, the buffer tank 9 is connected to the first diaphragm compressor unit 10 through a pipeline, the first diaphragm compressor unit 10 is connected to the first filling row 11 through a pipeline, and the first filling row 11 is connected to the high-purity helium inlet of the liquid helium tank truck 1.

[0035] In this embodiment, the recovery unit includes a second vaporizer 3, an airbag 5, a second diaphragm compressor unit 6 and a second filling row 7 which are connected in sequence along the flow direction of liquid nitrogen; the second vaporizer 3 is connected to the liquid helium outlet on the liquid helium Dewar flask 2 through a pipeline, the second vaporizer 3 is connected to the airbag 5 through a pipeline, and the airbag 5 is connected to the second filling row 7 through a pipeline;

[0036] In this embodiment, a three-way element is provided on the pipeline between the second vaporizer 3 and the airbag 5, one end of the three-way element is connected to the second vaporizer 3, one end is connected to the airbag 5, and one end is connected to the pipeline between the first vaporizer 8 and the buffer tank 9. A helium purity analyzer 4 is provided on the pipeline between the three-way element and the airbag 5 for monitoring the purity of the helium.

[0037] In this embodiment, the first diaphragm compressor unit 10 and the second diaphragm compressor unit 6 are both composed of a low-pressure diaphragm compressor and a high-pressure diaphragm compressor connected in series. The oil and gas separation during the compression process of the diaphragm compressor ensures that the helium is not contaminated. The design of the diaphragm compressor unit reduces the intake pressure, so that the low-purity helium generated in the initial stage of liquid helium filling is discharged in time, reducing the amount of industrial helium generated. In addition, the displacement of the unit is improved, ensuring the efficiency of helium filling.

[0038] Implementation principle:

[0039] In the specific process of filling liquid helium, high-purity helium is first filled, the second liquid helium outlet of the liquid helium tank car 1 is opened, and the liquid helium enters the first vaporizer 8 through the pipeline G. Under the action of the first vaporizer 8, the liquid helium with a small amount of air becomes helium. Since there is more air in the pipeline, a large amount of air is mixed in the initial helium, and the purity of the helium is low. Therefore, it enters the air bag 5 through the pipeline D and the pipeline C to form industrial helium with low purity. The industrial helium enters the second diaphragm compressor unit 6 through the pipeline E. Since the pressure of the helium mixed with air in the early stage is low, the low-purity helium generated in the initial stage of liquid helium filling is discharged in time through the low-pressure diaphragm compression and high-pressure diaphragm compressor in the second diaphragm compressor unit 6, reducing the amount of industrial helium generated. In addition, the displacement of the unit is improved, ensuring the efficiency of helium filling. Industrial helium enters the second filling row 7 along pipeline F. As time goes by, the air in the pipeline is gradually exhausted. After the helium purity analyzer 4 detects that the purity of the helium is qualified, the valve on pipeline D is closed to fill high-purity helium. The high-purity helium enters the buffer tank 9 along pipeline H, and then is filled with high-purity helium through pipeline I, the first diaphragm compressor unit 10 and pipeline J through the first filling row 11 in sequence.

[0040] Secondly, the buffer tank 9 storing high-purity helium in advance is opened through the high-purity helium filling unit, and the high-purity helium enters the first diaphragm compressor unit 10 along the I pipeline. Since the first diaphragm compressor is composed of a low-pressure diaphragm compressor and a high-pressure diaphragm compressor in series, the pressure and displacement of the high-purity helium passing through the first diaphragm compressor unit 10 are improved, and it enters the first filling row 11 along the pipeline G, and then enters the liquid helium tank truck 1 through the high-purity helium inlet on the liquid helium tank truck 1 along the pipeline K, accelerating the liquid helium to enter the liquid helium Dewar flask 2.

[0041] Finally, the first liquid helium outlet of the liquid helium tank car 1 is opened, and the liquid helium enters the liquid helium dewar 2 through the inlet of the liquid helium dewar 2 along the pipeline A to fill the liquid helium. During the liquid helium filling process, due to the presence of a certain amount of air in the liquid helium dewar 2 and the pipeline, the helium mixed with air initially overflows from the liquid helium dewar 2, passes through the second vaporizer 3, and enters the air bag 5 along the pipeline C to form industrial helium with low purity. The industrial helium enters the second diaphragm compressor unit 6 through the pipeline E. Due to the low pressure of the helium mixed with air in the early stage, the low-purity helium generated in the initial stage of liquid helium filling is discharged in time through the low-pressure diaphragm compression and high-pressure diaphragm compressor in the second diaphragm compressor unit 6, thereby reducing the amount of industrial helium generated. In addition, the displacement of the unit is improved, ensuring the efficiency of helium filling. Industrial helium enters the second filling row 7 along pipeline F. As time goes by, the air in the pipeline is gradually exhausted. After the helium purity analyzer 4 detects that the purity of the helium is qualified, high-purity helium can be filled through the first filling row 11. It can also enter the buffer tank 9 through pipelines D and H, and enter the first filling row 11 along the pipeline to be filled with high-purity helium.

[0042] Based on the device embodiment, embodiment 1 provides a liquid helium filling method.

[0043] Example 1

[0044] This embodiment provides a liquid helium filling method. During the specific operation, the liquid helium tank car 1 contains 4.5 tons of high-purity liquid helium. The high-purity helium is first filled. Before the liquid helium filling starts, a small amount of air is inevitably present in the pipeline, so that the helium generated in the initial stage of liquid helium filling is low-purity industrial helium. Before the liquid helium is filled, the initial pressure of the liquid helium tank car 1 is reduced by filling with high-purity helium, the initial flow rate of liquid helium filling is reduced, and the generation of helium is reduced, thereby reducing the generation of industrial helium and improving the yield; the vaporizer 8 is connected to the liquid helium tank car 1 through the pipeline G, and the liquid helium enters the first vaporizer 8 through the second liquid helium outlet on the liquid helium tank car through the pipeline G; the first vaporizer 8 vaporizes the liquid helium from the liquid helium tank car 1, and the vaporization amount of the first vaporizer 8 is 300N m 3 / h. Since it is mixed with helium at the beginning, industrial helium is first filled through pipelines D and C. After the purity of liquid helium is qualified, the valve on pipeline D is closed, and the high-purity helium is vaporized and then passed into buffer tank 9 through pipeline H. The volume of buffer tank 9 is 3m 3The buffer tank 9 is connected to the first diaphragm compressor unit 10 through a pipeline I; the first diaphragm compressor unit 10 is composed of a low-pressure diaphragm compressor and a high-pressure diaphragm compressor connected in series. The high-purity first diaphragm compressor unit 10 compresses and pressurizes the high-purity helium to be filled. The first diaphragm compressor unit 10 avoids contact between oil and helium to ensure the purity of helium. In addition, the large displacement of the unit ensures the helium filling efficiency. The first diaphragm compressor unit 10 is connected to the first filling row 11 through a pipeline J; the first filling row 11, the first filling row 11 is filled with high-purity helium. After the filling is completed, the residual high-pressure high-purity helium in the first filling row 11 flows back to the liquid helium tank car 1 through the pipeline K and the helium inlet, reducing the pressure difference between the liquid helium tank car and the liquid helium Dewar flask, and accelerating the liquid helium filling rate.

[0045] Liquid helium filling: Liquid helium flows into pipeline A through the first liquid helium outlet on the liquid helium tank car 1, and then enters the liquid helium dewar 2. The liquid helium dewar 2 has a volume of 500L and can be filled with 250kg of liquid helium at a time. During the liquid helium filling process, helium will be generated when the liquid helium dewar 2 is filled with liquid helium. There is air in the pipeline at the beginning, so the helium generated initially will be discharged together with the air, and the purity is unqualified. The helium generated during the filling process of the liquid helium dewar 2 flows into the second vaporizer 3 through pipeline B; the second vaporizer 3 vaporizes a small amount of liquid helium carried by the helium, and the industrial helium with lower purity after vaporization is passed into the airbag 9 through pipeline C. The vaporization volume of the vaporizer is 20N m 3 / h, the high-purity helium after the purity is tested to be qualified is introduced into the high-purity helium buffer tank 9 through the pipeline D to avoid the degradation of the high-purity helium; the helium purity analyzer 4 is installed on the pipeline C close to the airbag 5, and the helium purity analyzer 4 is used to detect the purity of helium. The helium purity higher than 99.999% is qualified high-purity helium, otherwise it is unqualified industrial helium; the airbag 5 stores the low-pressure industrial helium to be filled, and the volume of the airbag 5 is 15m 3 The air bag 5 is connected to the second diaphragm compressor unit 6 through a pipeline E. The second diaphragm compressor unit 6 is composed of a low-pressure diaphragm compressor and a high-pressure diaphragm compressor connected in series. The second diaphragm compressor unit 6 compresses and boosts the industrial helium to be filled. The diaphragm compressor avoids the contact between oil and helium to ensure the quality of helium. A small amount of air is inevitably present in the pipeline before the liquid helium filling begins. The design of the second diaphragm compressor unit 6 reduces the intake pressure while ensuring the helium filling efficiency, so that a small amount of helium is mixed when the air is discharged in the initial exhaust stage, thereby reducing the generation of industrial helium. The second diaphragm compressor unit 6 is connected to the second filling row 7 through a pipeline F; the second filling row 7 fills the industrial helium to achieve the percentage utilization of helium in the filling process and improve the resource utilization rate. After the subsequent helium is qualified, high-purity helium can be filled not only through the first filling row 10 but also through the second filling row 7.

[0046] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A liquid helium filling system, characterized in that: Including liquid helium filling unit, high-purity helium filling unit and industrial helium recovery unit; The liquid helium filling unit comprises a liquid helium tank car (1) and a liquid helium dewar flask (2), and the liquid helium tank car (1) and the liquid helium dewar flask (2) are connected to each other; The high-purity helium filling unit comprises a first vaporizer (8), a buffer tank (9), a first diaphragm compressor unit (10) and a first filling row (11) which are connected in sequence along the flow direction of liquid helium; the first vaporizer (8) is connected to the liquid helium tank truck (1); The recovery unit comprises a second vaporizer (3), an air bag (5), a second diaphragm compressor unit (6) and a second filling row (7) which are connected in sequence along the flow direction of liquid nitrogen; the second vaporizer (3) is connected to the liquid helium Dewar flask (2).

2. A liquid helium filling system according to claim 1, characterized in that: The liquid helium tank car (1) is provided with a first liquid helium outlet, a second liquid helium outlet and a high-purity helium inlet. The liquid helium dewar flask (2) is provided with a liquid helium inlet and a liquid helium outlet. The first liquid helium outlet is communicated with the liquid helium inlet of the liquid helium dewar flask (2) through a pipeline. The liquid helium outlet of the liquid helium dewar flask (2) is communicated with a second vaporizer (3) through a pipeline. The second vaporizer (3) is communicated with an air bag (5) through a pipeline. The air bag (5) is communicated with a second filling row (7) through a pipeline. The second liquid helium outlet of the liquid helium tank car (1) is communicated with the first vaporizer (8) through a pipeline. The first vaporizer (8) is communicated with a buffer tank (9) through a pipeline. The buffer tank (9) is communicated with a first diaphragm compressor unit (10) through a pipeline. The first diaphragm compressor unit (10) is communicated with a first filling row (11) through a pipeline. The first filling row (11) is communicated with the high-purity helium inlet of the liquid helium tank car (1).

3. A liquid helium filling system according to claim 1, characterized in that: A three-way element is provided on the pipeline between the second vaporizer (3) and the airbag (5), one end of the three-way element is connected to the second vaporizer (3), one end is connected to the airbag (5), and one end is connected to the pipeline between the first vaporizer (8) and the buffer tank (9). A helium purity analyzer (4) is provided on the pipeline between the three-way element and the airbag (5) for monitoring the purity of the helium.

4. A liquid helium filling system according to claim 1, characterized in that: The first diaphragm compressor unit (10) and the second diaphragm compressor unit (6) are both composed of a low-pressure diaphragm compressor and a high-pressure diaphragm compressor connected in series.

5. A liquid helium filling system according to claim 1, characterized in that: The first filling row (11) is connected to the high-purity helium inlet of the liquid helium tank car (1) through a pipeline.

6. A liquid helium filling method, characterized in that: The steps include: High-purity helium filling: liquid helium in the liquid helium tank car (1) enters the first vaporizer (8), and after the purity of the helium is qualified, high-purity helium is filled through the buffer tank (9), the first diaphragm compressor unit (10) and the first filling row (11). After the high-purity helium filling is completed, the residual helium in the first filling row (11) enters the liquid helium tank car (1); Liquid helium filling and helium recovery: Liquid helium from the liquid helium tank truck (2) enters the liquid helium dewar (2) for liquid filling, air and helium containing liquid helium enter the second vaporizer (3) to form industrial helium, and the industrial helium enters the air bag (5), the second membrane compressor unit (6) and the second filling row (7) for filling and recovery. After the purity of the helium is qualified, high-purity helium is filled through the first filling row (11) / the second filling row (7).

7. A liquid helium filling method according to claim 6, characterized in that: The qualified helium has a purity greater than 99.999%.

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