A liquid helium filling system and method

Abstract

The application relates to a liquid helium filling system and method, high-purity helium filling: liquid helium in a liquid helium tank truck enters a first vaporizer, after the purity of the helium is qualified, high-purity helium filling is carried out through a buffer tank, a first diaphragm compressor unit and a first filling line, after the high-purity helium filling is completed, residual helium in the first filling line enters the liquid helium tank truck; liquid helium filling and helium recovery: liquid helium in the liquid helium tank truck enters a liquid helium Dewar flask for liquid filling, air and helium containing liquid helium enter a second vaporizer to form industrial helium, the industrial helium enters a gas bag, a second diaphragm compressor unit and a second filling line for filling recovery, after the purity of the helium is qualified, high-purity helium is filled through the first filling line / second filling line. The liquid helium filling system and method provided by the application can improve the filling efficiency of liquid helium, and can realize simultaneous filling of liquid helium and helium and recovery of industrial helium in one set of device.

Description

Technical Field

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

[0002] Liquid helium is a cryogenic refrigerant widely used in scientific research, industrial production, and medical fields. With technological advancements and the expansion of its application areas, the demand for liquid helium is also increasing. To facilitate its transportation and use, we fill liquid helium into cylinders or dewar tanks using a filling system. In existing liquid helium filling systems, liquid helium flows from a liquid helium tank truck into a liquid helium dewar via a filling pipeline. In the initial filling phase, the pressure differential between the liquid helium tank truck and the liquid helium dewar is too large, resulting in an excessively fast flow rate and the generation of a large amount of low-purity industrial helium. Therefore, many researchers have attempted to develop a solution to the problem of helium waste caused by the large pressure differential. For example, Chinese patent publication No. CN219756030U discloses a helium filling system in which safety ball valves are provided at the liquid inlet and outlet ends of the dewar in the liquid helium filling pipeline. This system facilitates replacement of the dewar after filling with liquid helium, and also controls the pressure differential between the liquid helium tank truck and the dewar in the event of an excessive pressure differential. However, helium molecules are relatively small and can easily pass through gaps in the ball valve, causing leakage between the outer shell and the ball. Chinese patent publication number CN113324169A discloses a non-destructive helium filling process for a helium liquefier dewar. This process involves installing a pressure relief valve on the dewar to control the pressure difference between the liquid helium truck and the dewar. The system also incorporates pressure detection sensors, alarms, emergency stop controllers, and a remote monitoring system. This process is not only technically complex but also increases filling costs and results in significant helium waste.

[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 inlet 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 existing technology 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 existing technology. Summary of the Invention

[0005] To address the problems of excessive pressure difference, serious helium waste, and low filling efficiency in the liquid helium filling system in the prior art, the present application provides a liquid helium filling system and method, as follows:

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

[0007] In one aspect, the present application provides a liquid helium filling system, comprising a liquid helium filling unit, a high-purity helium filling unit, and an industrial helium recovery unit;

[0008] The liquid helium filling unit includes 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 includes a first vaporizer, a buffer tank, a first diaphragm compressor unit and a first filling row connected in sequence along the liquid helium flow direction; the first vaporizer is connected to the 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, and 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 a second vaporizer through a pipeline, the second vaporizer is communicated with an airbag through a pipeline, and the airbag is communicated with a 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 a buffer tank through a pipeline, the buffer tank is communicated with a first diaphragm compressor unit through a pipeline, the first diaphragm compressor unit is communicated with a 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 from the liquid helium tank truck enters the first vaporizer. After the helium purity meets the requirements, it is filled with high-purity helium 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 from 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 the industrial helium enters the air bag, the second membrane compressor unit and the second filling row for filling and recovery. After the helium purity meets the requirements, 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] This application utilizes a diaphragm compressor to effectively separate oil and gas, ensuring high-purity helium. The diaphragm compressor unit design reduces intake pressure and reduces the amount of industrial helium generated. Furthermore, the unit's displacement is increased, improving helium filling efficiency.

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

[0023] This application enables the simultaneous filling of high-purity helium and liquid helium within a single facility, while also allowing for the recovery of industrial helium. This simplifies the structure and layout of the filling system, making the entire process more efficient and convenient. For manufacturers, this new technology not only provides a completely 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 solutions of the embodiments of the present application, the drawings of the embodiments will be 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 figure:

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

[0028] Reference Signs List

[0029] 1. Liquid helium tank truck; 2. Liquid helium dewar; 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 illustrate the technical means and effects adopted by this application to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of this application are described in detail below in combination with 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 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 outlet on the liquid helium Dewar flask 2 through a pipeline, the second vaporizer 3 is connected to the air bag 5 through a pipeline, and the air bag 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 each consist 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 compressors ensures that the helium is not contaminated. The design of the diaphragm compressor units reduces the intake pressure, allowing the low-purity helium generated during the initial stage of liquid helium filling to be discharged promptly, reducing the amount of industrial helium generated. Furthermore, the units' displacement is increased, ensuring efficient helium filling.

[0038] Implementation principle:

[0039] During the specific liquid helium filling process, high-purity helium is first filled. The second liquid helium outlet of the liquid helium tanker 1 is opened, and the liquid helium enters the first vaporizer 8 through pipeline G. Under the action of the first vaporizer 8, the liquid helium with a small amount of air is converted into helium gas. Due to the large amount of air in the pipeline, the initial helium gas is mixed with a large amount of air, resulting in low purity. Therefore, it enters the air bag 5 through pipelines D and C, forming low-purity industrial helium. The industrial helium enters the second diaphragm compressor unit 6 through pipeline E. Due to the low pressure of the helium mixed with air in the early stage, the low-pressure diaphragm compression and high-pressure diaphragm compressor in the second diaphragm compressor unit 6 are used to promptly discharge the low-purity helium generated in the initial stage of liquid helium filling, reducing the amount of industrial helium generated. In addition, the displacement of the unit is improved, ensuring the efficiency of helium filling. Industrial helium flows along pipeline F into the second filling row 7. 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 and high-purity helium is filled. The high-purity helium flows along pipeline H into the buffer tank 9, and then flows through pipeline I, the first diaphragm compressor unit 10 and pipeline J through the first filling row 11 to fill the high-purity helium.

[0040] Secondly, the buffer tank 9 that has stored 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 first 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 increased, 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 tanker 1 is opened, and the liquid helium flows along pipeline A through the inlet of the liquid helium dewar 2 into the liquid helium dewar 2, where it is filled. During the filling process, due to the presence of a certain amount of air in the liquid helium dewar 2 and the pipeline, helium mixed with air initially overflows from the liquid helium dewar 2, passes through the second vaporizer 3, and enters the gas bag 5 along pipeline C, forming low-purity industrial helium. The industrial helium then enters the second diaphragm compressor unit 6 through pipeline E. Due to the low pressure of the helium mixed with air at the initial stage, the low-pressure diaphragm compression and high-pressure diaphragm compressor in the second diaphragm compressor unit 6 allow the low-purity helium generated in the initial stage of liquid helium filling to be discharged promptly, reducing the amount of industrial helium generated. In addition, the unit's displacement 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 operation, a liquid helium tank truck 1 contains 4.5 tons of high-purity liquid helium. The high-purity helium is first filled. Before the liquid helium filling begins, 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 filling, the initial pressure of the liquid helium tank truck 1 is reduced by filling with high-purity helium, thereby reducing the initial flow rate of liquid helium filling, reducing the generation of helium, and thus reducing the generation of industrial helium and improving the yield. The vaporizer 8 is connected to the liquid helium tank truck 1 through a pipeline G. The liquid helium enters the first vaporizer 8 through the second liquid helium outlet on the liquid helium tank truck and the pipeline G. The first vaporizer 8 vaporizes the liquid helium from the liquid helium tank truck 1. The vaporization rate of the first vaporizer 8 is 300 N m 3 / h, because of the mixed helium at the beginning, first fill the industrial helium through pipeline D and pipeline C. After the purity of liquid helium is qualified, close the valve on pipeline D, and the high-purity helium is vaporized and then passed into buffer tank 9 through pipeline H. The volume of buffer tank 9 is 3 m 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 used to fill the 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 truck 1 through the pipeline K and the helium inlet, reducing the pressure difference between the liquid helium tank truck and the liquid helium Dewar flask, and accelerating the liquid helium filling rate.

[0045] Liquid helium filling: Liquid helium flows into pipe A through the first liquid helium outlet on the liquid helium tanker 1, and then enters the liquid helium dewar 2. The liquid helium dewar 2 has a volume of 500 L and can hold 250 kg of liquid helium at a time. During the filling process, helium gas is generated when the liquid helium dewar 2 is filled with liquid helium. Initially, there is air in the pipeline, so the initially generated helium gas is discharged along with the air, resulting in substandard purity. The helium gas generated during the filling process of the liquid helium dewar 2 flows into the second vaporizer 3 through pipe B. The second vaporizer 3 vaporizes a small amount of liquid helium carried by the helium gas. After vaporization, the industrial helium with lower purity is passed through pipe C into the airbag 5. The vaporizer vaporization rate is 20 N m 3 / h, after the purity is tested and qualified, the high-purity helium 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 air bag 5. The helium purity analyzer 4 is used to detect the purity of the helium. If the helium purity is higher than 99.999%, it is qualified high-purity helium, otherwise it is unqualified industrial helium; the air bag 5 stores the low-pressure industrial helium to be filled, and the volume of the air bag 5 is 15 m 3 The air bag 5 is connected to the second diaphragm compressor unit 6 through the 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 contact between oil and helium to ensure the quality of helium. A small amount of air is inevitably present in the pipeline before 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, reducing the generation of industrial helium. The second diaphragm compressor unit 6 is connected to the second filling row 7 through the pipeline F; the second filling row 7 fills the industrial helium, realizes the percentage utilization of helium in the filling process, and improves resource utilization. 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 description is merely 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 above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above 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), wherein 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) 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); The liquid helium tank car (1) is provided with a first liquid helium outlet, a second liquid helium outlet and a high-purity helium gas inlet, and 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 the second vaporizer (3) through a pipeline, the second vaporizer (3) is communicated with the air bag (5) through a pipeline, and the air bag (5) is communicated with the 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 the buffer tank (9) through a pipeline, the buffer tank (9) is communicated with the first diaphragm compressor unit (10) through a pipeline, the first diaphragm compressor unit (10) is communicated with the first filling row (11) through a pipeline, and the first filling row (11) is communicated with the high-purity helium gas inlet of the liquid helium tank car (1); 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), and 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; 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.

2. 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.

3. A liquid helium filling method, based on a liquid helium filling system according to any one of claims 1 to 2, characterized in that: The steps include: High-purity helium filling: liquid helium from the liquid helium tank car (1) enters the first vaporizer (8), and after the helium purity 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 (1) enters the liquid helium dewar (2) for liquid filling, and air and helium containing liquid helium enter the second vaporizer (3) to form industrial helium. 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 helium purity is qualified, high-purity helium is filled through the first filling row (11) / the second filling row (7).

4. A liquid helium filling method according to claim 3, characterized in that: The qualified helium has a purity greater than 99.999%.

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