Pressure sensor helium protection structure applied to superfluid helium negative pressure pipeline

Abstract

The invention relates to the technical field of low-temperature engineering, and relates to a pressure sensor helium protection structure applied to a superfluid helium negative pressure pipeline, which comprises a sealed container, and a pressure sensor on the superfluid helium negative pressure pipeline is positioned in the sealed container. A superfluid helium negative pressure pipeline connected with the pressure sensor enters the sealed container and is in sealed connection with the sealed container, the sealed container is provided with a gas inlet pipeline, and the helium source provides micro-positive pressure helium for the sealed container through the gas inlet pipeline; the pressure sensor on the superflow helium negative pressure pipeline is arranged in the sealed container, and the container is filled with micro-positive pressure helium, so that the structure can ensure that external air cannot be leaked into a negative pressure pipeline system through the pressure sensor under any condition, and the safety of the system is ensured. Therefore, external air is prevented from entering the superflow helium negative pressure pipeline when the system is shut down or micro leakage occurs at the interface of the pressure sensor, so that the pollution of the whole system is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of cryogenic engineering, and in particular to a helium protection structure for a pressure sensor applied to a superfluid helium negative pressure pipeline. Background Art

[0002] With the rapid development of modern science and technology, large-scale scientific projects such as particle accelerators and controlled nuclear fusion devices are advancing at an unprecedented speed. These cutting-edge scientific devices not only require superconducting magnets and superconducting acceleration cavities to achieve stronger magnetic field strengths and higher acceleration gradients, but also place more stringent requirements on the helium cryogenic system that provides them with cold. Traditionally, helium cryogenic systems mainly operate in the 4.2K liquid helium temperature zone, but in order to further explore the properties of matter at lower temperatures, especially to reach the 2K superfluid helium temperature zone, the pipeline system must introduce a negative pressure environment to maintain this extremely low temperature state.

[0003] The current ultra-low temperature freezers are mainly used in the 4.2K liquid helium temperature zone. The connection structure between the pressure sensor and the pipeline is mainly threaded and metal-sealed ferrule joints. The sealing effect of these two connection structures is not good and there is a possibility of leakage. However, the pipeline in this temperature zone is a positive pressure environment. When the internal pressure of the system is greater than the external pressure, it is not easy for the external air to enter the internal system. However, in the negative pressure pipeline, when the system is shut down or there is a slight leak at the temperature sensor interface, the external air can easily enter the low temperature system and cause pollution to the entire system. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline, aiming to solve the problem that when the system is shut down or a micro-leak occurs at the temperature sensor interface in the negative pressure pipeline, external air can easily enter the low-temperature system and cause contamination of the entire system.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: comprising a sealed container, a pressure sensor on a superfluid helium negative pressure pipeline is located in the sealed container, a superfluid helium negative pressure pipeline connected to the pressure sensor enters the sealed container and is sealedly connected to the sealed container, the sealed container has an air inlet pipeline, and a helium source provides slightly positive pressure helium to the sealed container through the air inlet pipeline.

[0006] Furthermore, it also includes a pressure control valve arranged on the air inlet pipeline, and the pressure control valve can control the pressure of the helium provided by the helium source, and control the pressure of the helium entering the sealed container to a slight positive pressure.

[0007] Furthermore, it also includes a pressure gauge arranged on the air inlet pipeline, which is arranged between the pressure control valve and the sealed container and is used to measure and display the pressure value of the slightly positive pressure helium gas connected to the sealed container.

[0008] Furthermore, it also includes an intake valve arranged on the intake pipeline, a helium source is connected to the intake valve pipeline, and the helium source delivers helium to the intake pipeline through the intake valve.

[0009] Furthermore, the sealed container also includes an exhaust pipeline, and a safety valve is provided on the exhaust pipeline to discharge helium in time when the container is over-pressured.

[0010] Furthermore, the sealed container includes a container body and a first flange, a second flange sealed and connected to the first flange is integrally formed at one end of the container body, a sealing member is arranged between the first flange and the second flange, the sealing member is sealed and connected to the first flange and the second flange, a superfluid helium negative pressure pipeline passes through the first flange and the sealing member in sequence and enters the sealed container, and the sealing member is in sealing contact with the superfluid helium negative pressure pipeline.

[0011] Further, the sealing member is a transition sealing disk arranged between the first flange and the second flange.

[0012] Furthermore, O-rings are provided between the transition sealing disc and the first flange and the second flange.

[0013] Furthermore, the sealed container also includes an end cover which is detachably arranged on the container body and sealedly connected to the container body.

[0014] Furthermore, an aviation plug is provided on the sealed container, and the pressure sensor in the sealed container is electrically connected to the external controller through the aviation plug.

[0015] The present invention discloses a helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline and a control method thereof, which has the beneficial effect that by placing the pressure sensor on the superfluid helium negative pressure pipeline in a sealed container and filling the interior of the container with slightly positive pressure helium, the structure can ensure that under no circumstances can external air leak into the negative pressure pipeline system through the pressure sensor, which avoids external air from entering the superfluid helium negative pressure pipeline when the system is shut down or a slight leak occurs at the pressure sensor interface, thereby preventing contamination of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a stereogram of an embodiment of a helium protection structure for a pressure sensor of the present invention;

[0017] Figure 2 It is a plan view of an embodiment of a helium protection structure for a pressure sensor of the present invention.

[0018] Explanation of the reference numerals: 1. Container body; 11. Air inlet pipeline; 111. Air inlet valve; 112. Pressure control valve; 113. Pressure gauge; 12. Exhaust pipeline; 121. Safety valve; 13. First flange; 14. Second flange; 15. Transition sealing disk; 16. End cover; 17. Aviation plug; 2. Pressure sensor; 3. Superfluid helium negative pressure pipeline. DETAILED DESCRIPTION

[0019] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0020] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions 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 cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0021] In order to further illustrate the principle and structure of the present invention, preferred embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0022] like Figure 1 As shown, an embodiment of the present invention provides a helium protection structure for a pressure sensor 2 applied to a superfluid helium negative pressure pipeline 3, comprising: a sealed container, the pressure sensor 2 on the superfluid helium negative pressure pipeline 3 is located in the sealed container, the superfluid helium negative pressure pipeline 3 connected to the pressure sensor 2 enters the sealed container and is sealedly connected to the sealed container; the sealed container has an air inlet pipeline 11, an external helium source is connected to the air inlet pipeline 11, and slightly positive pressure helium is provided to the sealed container through the air inlet pipeline 11.

[0023] The sealed container provides a fully enclosed environment, completely isolating the pressure sensor 2 from the external environment. An external helium source provides slightly positive pressure helium to the sealed container, so that the helium fills the sealed chamber, and the slightly positive pressure helium can increase the pressure inside the container to make it slightly higher than the external environment, which can effectively prevent the entry of external air and improve the sealing effect of the sealed container; and the helium can form a protective layer around the pressure sensor 2. When a slight leak occurs at the temperature sensor interface, it can ensure that the air entering the superfluid helium negative pressure pipeline 3 is helium, preventing external air from entering the system.

[0024] By placing the pressure sensor 2 on the superfluid helium negative pressure pipeline 3 in a sealed container and filling the interior of the container with slightly positive pressure helium, this structure can ensure that under no circumstances can external air leak into the negative pressure pipeline system through the pressure sensor 2. This avoids external air from entering the superfluid helium negative pressure pipeline 3 when the system is shut down or a slight leak occurs at the interface of the pressure sensor 2, thereby preventing contamination of the entire system.

[0025] Furthermore, the above-mentioned sealed container includes a container body 1 and a first flange 13. The container body 1 is a hollow cylindrical structure. The first flange 13 is sealed and connected to the lower end of the container body 1. The lower end of the container body 1 is integrally formed with a second flange 14 that is compatible with the first flange 13. The first flange 13 and the second flange 14 are sealed and connected and fixed by bolts.

[0026] The first flange 13 is provided with a through hole corresponding to the pipeline (superfluid helium negative pressure pipeline 3) connected to the pressure sensor 2. The pipeline connected to the pressure sensor 2 can pass through the through hole from the bottom of the sealed container upward into the sealed container.

[0027] Furthermore, in order to enhance the sealing between the sealed container and the pipeline and prevent the helium in the sealed container from leaking outward, a seal is also provided. The seal is provided between the first flange 13 and the second flange 14 and is sealedly connected to the first flange 13 and the second flange 14. The pipeline needs to pass through the first flange 13 and the seal in sequence to enter the sealed container. The seal is in sealing contact with the pipeline to improve the sealing performance of the sealed container.

[0028] Specifically, the seal is a transition sealing disk 15 arranged between the first flange 13 and the second flange 14. The transition sealing disk 15 is made of rubber or silicone. A through hole that can fit tightly with the pipeline is opened on the transition sealing disk 15. After the pipeline passes through the transition sealing disk 15, the inner wall of the through hole of the transition sealing disk 15 fits tightly with the pipeline, thereby enhancing the sealing performance of the sealed container.

[0029] Furthermore, O-rings are provided between the transition sealing disc 15 and the first flange 13 and the second flange 14 , so as to achieve a sealed connection between the transition sealing disc 15 and the first flange 13 and the second flange 14 .

[0030] Furthermore, the sealed container also includes a detachable end cover 16 with a flange on the upper end of the container body 1. The end cover 16 is sealed and connected to the container body 1. The detachable end cover 16 facilitates the installation or removal of the pressure sensor 2 and also facilitates the wiring inside the sealed container.

[0031] Furthermore, an aviation plug 17 is provided on the sealed container, and the pressure sensor 2 in the sealed container is electrically connected to the aviation plug 17. The aviation plug 17 facilitates leading the control line of the pressure sensor 2 to the outside, so as to facilitate the electrical connection of the pressure sensor 2 with an external controller.

[0032] Furthermore, in order to control the helium pressure provided by the helium source and maintain the safety of the system, a pressure control valve 112 is also provided on the air inlet pipeline 11. The pressure control valve 112 can accurately adjust the flow rate and pressure of the slightly positive pressure helium entering the sealed container to ensure that the helium in the container is maintained at a suitable slightly positive pressure state. This is to protect the superfluid helium negative pressure pipeline 3, prevent external air from entering the sealed chamber through possible leakage points, and avoid the superfluid helium negative pressure pipeline 3 from inhaling external air.

[0033] Furthermore, it also includes a pressure gauge 113 arranged on the air inlet pipeline 11. The pressure gauge 113 is arranged between the pressure control valve 112 and the sealed container. The pressure gauge 113 measures and displays the pressure value of the slightly positive pressure helium connected to the sealed container. The operator can intuitively understand the pressure situation in the helium container through the pressure gauge 113 to ensure that the helium is maintained at a suitable slightly positive pressure state to effectively isolate the outside air.

[0034] Furthermore, it also includes an intake valve 111 arranged on the intake pipeline 11, and the helium source is connected to the intake valve 111 pipeline. The helium source delivers helium to the intake pipeline 11 through the intake valve 111. The operator can quickly adjust and maintain the pressure environment in the sealed container by opening or closing the intake valve 111.

[0035] Furthermore, in addition to the air inlet pipeline 11, the sealed container also includes an exhaust pipeline 12. The exhaust pipeline 12 is mainly used to discharge excess helium when the internal pressure of the sealed container exceeds the set safety value. By timely discharging the over-pressure gas, the exhaust pipeline 12 helps to maintain the stability of the internal pressure of the system and ensure that the equipment operates safely within the specified pressure range.

[0036] In order to discharge excess helium when the pressure inside the sealed container exceeds the set safety value, the exhaust pipeline 12 is provided with a safety valve 121. When the pressure inside the sealed container exceeds the set safety threshold, the safety valve 121 will automatically open to release part of the helium to reduce the pressure. The safety valve 121 can respond quickly without human intervention, effectively preventing the occurrence of overpressure accidents and ensuring the stable operation and safety of the system.

[0037] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline, characterized in that: include: The sealed container has a pressure sensor on the superfluid helium negative pressure pipeline located in the sealed container, and the superfluid helium negative pressure pipeline connected to the pressure sensor enters the sealed container and is sealedly connected to the sealed container; the sealed container has an air inlet pipeline, and a helium source provides slightly positive pressure helium to the sealed container through the air inlet pipeline.

2. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 1, characterized in that: It also includes a pressure control valve arranged on the air inlet pipeline, which can control the pressure of the helium provided by the helium source and control the pressure of the helium entering the sealed container to a slight positive pressure.

3. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 2, characterized in that: It also includes a pressure gauge arranged on the air inlet pipeline, which is arranged between the pressure control valve and the sealed container and is used to measure and display the pressure value of the slightly positive pressure helium gas connected to the sealed container.

4. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 3, characterized in that: It also includes an intake valve arranged on the intake pipeline, a helium source is connected to the intake valve pipeline, and the helium source delivers helium to the intake pipeline through the intake valve.

5. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 1, characterized in that: The sealed container also includes an exhaust pipeline, on which a safety valve is arranged so as to discharge helium in time when the container is over-pressured.

6. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 1, characterized in that: The sealed container includes a container body and a first flange. A second flange sealed and connected to the first flange is integrally formed at one end of the container body. A sealing member is arranged between the first flange and the second flange. The sealing member is sealed and connected to the first flange and the second flange. A superfluid helium negative pressure pipeline passes through the first flange and the sealing member in sequence and enters the sealed container. The sealing member is in sealing contact with the superfluid helium negative pressure pipeline.

7. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline according to claim 6, characterized in that: The sealing member is a transition sealing disk arranged between the first flange and the second flange.

8. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 7, characterized in that: O-type sealing rings are arranged between the transition sealing disk and the first flange and the second flange.

9. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline as claimed in claim 6, characterized in that: The sealed container also includes an end cap which is detachably arranged on the container body and sealedly connected to the container body.

10. The helium protection structure for a pressure sensor used in a superfluid helium negative pressure pipeline according to claim 1, characterized in that: An aviation plug is provided on the sealed container, and the pressure sensor in the sealed container is electrically connected to an external controller through the aviation plug.

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