A structure and method for arranging temperature sensors in the inlet and outlet liquid nitrogen pipelines of a cold box.

Abstract

This invention belongs to the field of cryogenic pipeline sensor arrangement technology, and particularly relates to a temperature sensor arrangement structure and method for liquid nitrogen pipelines at the inlet and outlet of a cold box. The arrangement structure includes a temperature sensor, a cryogenic pipeline, an annular corrugated pipe, a protective pipe, and a cover plate. The protective pipe is welded and fixed to the cryogenic pipeline, which includes an outer pipe and an inner pipe. The temperature sensor passes through the outer and inner pipes and exits from the protective pipe. The cover plate has an injection port inside, and one end of the temperature sensor is provided with an adjustable connection structure. The temperature sensor exits the cover plate through the injection port. After adjusting the installation angle of the temperature sensor using the adjustable connection structure, the temperature sensor is sealed and fixed to the cover plate. One end of the annular corrugated pipe is welded and fixed to the bottom of the cover plate, and the other end is welded and fixed to the protective pipe. The annular corrugated pipe is used for length compensation of the temperature sensor under cold contraction. Compared with the prior art, this invention can further improve the accuracy and reliability of the measurement results.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic pipeline sensor arrangement technology, and in particular relates to a temperature sensor arrangement structure and method for liquid nitrogen pipelines at the inlet and outlet of a cold box. Background Technology

[0002] The cold box used in the refrigeration system of a superconducting power device is one of the key pieces of equipment in the application of superconducting technology, and its performance directly affects the stable operation and efficiency of the superconducting power device. To ensure the normal operation of the cold box, its refrigeration effect needs to be monitored regularly using temperature sensors.

[0003] Chinese utility model patent CN205958136U discloses a pipeline temperature sensor, including a fixing unit, a filler, a thermistor, and a wire harness for connecting the thermistor. The pipeline temperature sensor can be directly installed on the pipeline being measured without the need for other components for fixation, thus simplifying the structure. At the same time, the pipeline temperature sensor can fit tightly with the pipeline being measured, avoiding gaps, and therefore can accurately control the pipeline temperature. In traditional temperature sensor placement methods, sensors are typically inserted directly into the liquid nitrogen pipeline. This approach has several limitations: First, the liquid nitrogen pipelines at the inlet and outlet of the cold box may exhibit a gas-liquid two-phase coexistence state. This state is unstable near the fluid's boiling point, especially when pressure fluctuations are significant at the Dewar inlet and outlet, easily leading to phase reversal and large, irregular fluctuations in cooling temperature. The flow of liquid nitrogen in the pipeline may generate a radial temperature gradient. If the sensor position cannot be adjusted according to actual needs, this radial temperature change cannot be accurately measured, potentially resulting in inaccurate measurements. Second, due to the contraction caused by liquid nitrogen flowing in the pipeline, traditional sensors cannot effectively compensate for this contraction, affecting measurement accuracy. Furthermore, most temperature sensors are connected by wires. When a gas-liquid two-phase flow exists in the liquid nitrogen pipeline, the sensor is affected by buoyancy, causing it to float on the liquid nitrogen surface and preventing accurate measurement of the internal liquid temperature. In conclusion, traditional temperature sensor placement methods are unsuitable for applications requiring precise control and monitoring of liquid nitrogen temperature. Therefore, it is urgent to design a temperature sensor layout scheme suitable for ultra-low temperature and high-precision temperature control scenarios to further improve the accuracy and reliability of measurement results. Summary of the Invention

[0004] The purpose of this invention is to provide a structure and method for arranging temperature sensors in the inlet and outlet liquid nitrogen pipelines of a cold box. This allows for adjustment of the installation angle of the temperature sensors and length compensation under cold contraction, thereby further improving the accuracy and reliability of the measurement results.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] This invention provides a temperature sensor arrangement structure for the inlet and outlet liquid nitrogen pipeline of a cold box, including a temperature sensor, a cryogenic pipeline, an annular corrugated pipe, a protective pipe, and a cover plate;

[0007] The protective tube is welded and fixed to the cryogenic pipeline, which includes an outer tube and an inner tube. The temperature sensor passes through the outer tube and the inner tube and exits from the protective tube. The cover plate has a glue injection port inside, and the end of the temperature sensor near the outer tube passes through the glue injection port to exit the cover plate. The temperature sensor is sealed and fixed to the cover plate. The height of the end of the temperature sensor near the inner tube is not higher than the liquid level height of the inner tube. The end of the temperature sensor near the inner tube is provided with an adjustable connection structure for adjusting the installation angle of the temperature sensor in the circumferential direction. One end of the annular corrugated pipe is welded and fixed to the bottom of the cover plate, and the other end is fixedly connected to the end of the protective tube near the outer tube. The annular corrugated pipe is used to compensate for the length of the temperature sensor under cold contraction.

[0008] Furthermore, a guardrail is provided at the bottom of the glue injection port. One end of the guardrail is fixedly connected to the bottom of the cover plate, and the other end is fixedly connected to the end of the annular corrugated pipe near the cover plate. The guardrail has a through hole coaxial with the glue injection port. After the temperature sensor passes through the through hole, glue is injected into the through hole to fix the temperature sensor and the guardrail.

[0009] Furthermore, after the temperature sensor protrudes from the cover plate, low-temperature adhesive is injected into the injection port to seal and fix the temperature sensor to the cover plate.

[0010] Furthermore, the bottom of the injection port is provided with an injection groove, and the cross-sectional area of ​​the injection groove is larger than the cross-sectional area of ​​the injection port.

[0011] Furthermore, one end of the annular corrugated pipe is fixedly connected to the end of the protective pipe near the outer pipe via a flange. The flange includes an upper flange and a lower flange. The upper flange is welded and fixed to the annular corrugated pipe, and the lower flange is welded and fixed to the protective pipe. The upper flange and the lower flange are connected by a snap-fit, and a sealing ring is provided between the upper flange and the lower flange.

[0012] Furthermore, matching bolts and nuts are provided between the upper flange and the lower flange.

[0013] Furthermore, the cross-sectional area and length of the temperature sensor are designed using the following formula:

[0014] Φ=Aλ(T h -T c) / δ,

[0015] Where Φ is the heat conduction, A is the cross-sectional area of ​​the temperature sensor, δ is the length of the temperature sensor, and T is the thermal conductivity. h For ambient temperature, T c λ represents the temperature of the cryogenic fluid and λ represents the thermal conductivity.

[0016] Furthermore, the adjustable connection structure is a universal joint or an angle knob.

[0017] Furthermore, an epoxy fiberglass support is installed inside the protective tube, and the temperature sensor is tightly fixed to the epoxy fiberglass support by spiral winding.

[0018] The present invention also provides a method for arranging temperature sensors for inlet and outlet liquid nitrogen pipelines of a cold box based on the above-described arrangement structure, comprising the following steps:

[0019] Welding protective pipe and low temperature pipeline, with temperature sensor inserted through outer and inner pipes and exiting from the protective pipe;

[0020] One end of the annular corrugated pipe is welded and fixed to the bottom of the cover plate, and the other end is fixedly connected to the end of the protective pipe near the outer pipe. The end of the temperature sensor near the outer pipe passes through the glue injection port set inside the cover plate. The height of the end of the temperature sensor near the inner pipe is not higher than the liquid level height of the inner pipe.

[0021] The installation angle of the temperature sensor can be adjusted along the circumference using the adjustable connection structure until it meets the user's requirements. After the angle adjustment is completed, adhesive is poured into the injection port to seal and fix the temperature sensor to the cover plate.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. This invention proposes a temperature sensor arrangement structure for the inlet and outlet liquid nitrogen pipeline of a cold box, including a temperature sensor, a cryogenic pipeline, an annular corrugated pipe, a protective pipe, and a cover plate. The protective pipe is welded and fixed to the cryogenic pipeline, which includes an outer pipe and an inner pipe. The temperature sensor passes through the outer and inner pipes and exits from the protective pipe, achieving a smooth transition between room temperature and cryogenic temperature, thus reducing the impact of temperature fluctuations on the measurement results. The cover plate has an injection port inside, and the end of the temperature sensor near the outer pipe exits the cover plate through the injection port, sealing the temperature sensor to the cover plate. The height of the end of the temperature sensor near the inner pipe is no higher than the liquid level height of the inner pipe, enabling temperature measurement at all radial positions. One end is equipped with an adjustable connection structure, which allows the installation angle of the temperature sensor to be adjusted circumferentially. Through this setting, the orientation and angle of the temperature sensor can be conveniently adjusted according to the actual measurement environment and the position of the target object, thereby ensuring the accuracy and reliability of the measurement results. One end of the annular corrugated pipe is welded and fixed to the bottom of the cover plate, and the other end is fixedly connected to the end of the protective tube near the outer tube. When the protective tube comes into contact with the low-temperature fluid in the low-temperature pipeline, it will produce a cold contraction phenomenon. The annular corrugated pipe has extensibility and can compensate for the length under the cold contraction phenomenon, avoiding excessive stress at the connection between the temperature sensor and the cover plate, achieving complete sealing of the temperature sensor, and further improving the accuracy and reliability of the measurement results.

[0024] 2. This invention features a guardrail at the bottom of the injection port. One end of the guardrail is fixedly connected to the bottom of the cover plate, and the other end is fixedly connected to an annular corrugated pipe. The guardrail has a through hole coaxial with the injection port. After the temperature sensor passes through the through hole, adhesive is injected into the through hole to fix the temperature sensor to the guardrail. This further secures the temperature sensor axially and radially, ensuring that it will not fall downwards due to gravity during use. After the temperature sensor passes through the cover plate, low-temperature adhesive is injected into the injection port to seal and fix the temperature sensor to the cover plate. An injection groove is provided at the bottom of the injection port, with a cross-sectional area larger than that of the injection port. In this way, the low-temperature adhesive can fully fill the injection port and the injection groove, achieving a complete seal for the temperature sensor. These measures effectively fix the temperature sensor, preventing displacement or detachment during use, thus maintaining the internal vacuum, ensuring the normal operating environment of the temperature sensor, and improving the stability and reliability of the measurement results.

[0025] 3. In this invention, one end of the annular corrugated pipe is fixedly connected to the end of the protective pipe near the outer pipe via a flange. Specifically, the flange includes an upper flange and a lower flange. The upper flange is welded and fixed to the annular corrugated pipe, and the lower flange is welded and fixed to the protective pipe. The upper flange and the lower flange are connected by snap fasteners. If the temperature sensor needs to be replaced, simply loosen the snap fasteners to replace the entire upper flange, facilitating the replacement of the temperature sensor later to meet diverse application scenarios and actual needs. A sealing ring is provided between the upper flange and the lower flange to ensure the sealing performance at the connection. Matching bolts and nuts are also provided between the upper flange and the lower flange. The bolts and nuts, through precise tightening torque, can ensure a tight fit between the upper and lower flanges, further enhancing the sealing effect.

[0026] 4. In this invention, the temperature sensor is tightly fixed to the epoxy fiberglass support by spiral winding. This design enables the temperature sensor to effectively measure the radial and axial temperature distribution of the fluid inside the pipe. At this time, the temperature sensor can fully cover all areas inside the pipe, thereby ensuring the comprehensiveness and accuracy of the monitoring data. The use of epoxy fiberglass support not only provides stable support for the temperature sensor, but also has good corrosion resistance and low thermal conductivity, ensuring the reliability and long-term stability of the entire measurement system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a magnified schematic diagram of a portion of the cover plate;

[0029] Explanation of reference numerals in the attached drawings: 1. Temperature sensor; 2. Outer tube; 3. Inner tube; 4. Injection port; 5. Guardrail plate; 6. Annular corrugated pipe; 7. Upper flange; 8. Lower flange; 9. Protective tube; 10. Adjustable connection structure; 11. Cover plate; 12. Injection groove. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. Example 1

[0031] This embodiment provides a temperature sensor arrangement structure for the inlet and outlet liquid nitrogen pipelines of a cold box, such as... Figure 1 As shown, it includes a temperature sensor 1, a low-temperature pipe, an annular corrugated pipe 6, a protective pipe 9, and a cover plate 11.

[0032] The cryogenic pipeline includes a horizontally arranged outer pipe 2 and an inner pipe 3. The protective pipe 9 is tightly connected to the outer pipe 2 by welding to ensure the airtightness between the two and prevent any possible leakage. At the same time, the protective pipe 9 passes through the outer pipe 2 and is welded to the inner pipe 3. This double welding method further ensures the airtightness of the entire cryogenic pipeline, enabling it to withstand the pressure and temperature changes in the cryogenic environment.

[0033] Temperature sensor 1 passes through outer tube 2 and inner tube 3, exiting from protective tube 9. The height of the end of temperature sensor 1 near inner tube 3 is no higher than the liquid level in inner tube 3. This height limitation allows temperature sensor 1 to measure temperature at all radial positions. After this structure is arranged, the protective tube is in a vacuum state, enabling a smooth transition from room temperature to low temperature, reducing stress changes caused by temperature fluctuations, thus maintaining the stability of temperature sensor 1, extending its service life, and improving measurement accuracy and reliability. The cover plate 11 has a glue injection port 4 inside. An adjustable connection structure 10 is provided at the end of temperature sensor 1 near inner tube 3. The adjustable connection structure 10 can be a universal joint or an angle knob. Through the adjustable connection structure 10, the installation angle of temperature sensor 1 can be finely adjusted along the circumferential direction, thus fully adapting to the temperature measurement needs of different liquid levels and different circumferential positions within the pipeline, to meet diverse application scenarios and practical requirements.

[0034] In a preferred embodiment, the protective tube 9 is provided with an integrated support frame, on which the temperature sensor 1 is fixed. The shape of the support frame includes, but is not limited to, cylindrical and rectangular, and the material includes, but is not limited to, epoxy fiberglass. For example, the temperature sensor 1 can be tightly fixed to the epoxy fiberglass support by spiral winding. This design allows the temperature sensor to effectively measure the radial and axial temperature distribution of the fluid inside the pipe. In this case, the temperature sensor can fully cover all areas inside the pipe, thereby ensuring the comprehensiveness and accuracy of the monitoring data. The use of epoxy fiberglass support not only provides stable support for the temperature sensor, but also has good corrosion resistance and low thermal conductivity, ensuring the reliability and long-term stability of the entire measurement system.

[0035] After the temperature sensor 1 exits from the protective tube 9, it passes through the glue injection port 4 and out of the cover plate 11. The installation angle of the temperature sensor 1 is adjusted using the adjustable connection structure 10, and then the temperature sensor 1 is sealed and fixed to the cover plate 11. In this embodiment, the sealing and fixing method is adhesive bonding. Specifically, after the temperature sensor 1 exits the cover plate 11, low-temperature adhesive is injected into the glue injection port 4. The low-temperature adhesive can ensure the sealing and stability of the connection in a low-temperature environment.

[0036] In a preferred embodiment, such as Figure 2As shown, a glue injection groove 12 is provided at the bottom of the glue injection port 4. The cross-sectional area of ​​the glue injection groove 12 is larger than that of the glue injection port 4. This ensures that the low-temperature adhesive is evenly distributed inside the glue injection port and the glue injection groove during the glue injection process, achieving full filling and thus achieving complete sealing of the temperature sensor 1.

[0037] In another preferred embodiment, a guardrail 5 is provided at the bottom of the glue injection port 4, such as... Figure 2 As shown, the guardrail piece 5 can be U-shaped, with one end fixedly connected to the bottom of the cover plate 11 and the other end fixedly connected to the end of the annular corrugated pipe 6 near the cover plate 11. The guardrail piece 5 has a through hole coaxial with the glue injection port 4. After the temperature sensor 1 passes through the through hole, glue is injected into the through hole to fix the temperature sensor 1 to the guardrail piece 5. This further secures the temperature sensor 1 axially and radially, preventing displacement or detachment due to gravity during use, thus maintaining the internal vacuum level, ensuring the temperature sensor 1 has a normal working environment, and improving the stability and reliability of the measurement results.

[0038] One end of the annular corrugated pipe 6 is welded and fixed to the bottom of the cover plate 11, and the other end is fixedly connected to the protective pipe 9. In a preferred embodiment, the fixed connection can be made through a flange. Figure 1 As shown, the flange includes an upper flange 7 and a lower flange 8. The upper flange 7 is welded and fixed to the annular bellows 6, and the lower flange 8 is welded and fixed to the protective pipe 9. The upper flange 7 and the lower flange 8 are connected by snap-fit, and a sealing ring is provided between the upper flange 7 and the lower flange 8. This flange connection method ensures both the stability and airtightness of the connection. Furthermore, if the temperature sensor 1 needs to be replaced later, only the snap-fit ​​between the upper flange 7 and the lower flange 8 needs to be loosened to replace the entire part above the upper flange 7, making it more convenient and quick. In a preferred embodiment, matching bolts and nuts are provided between the upper flange 7 and the lower flange 8. The bolts and nuts, through precise tightening torque, ensure a tight fit between the upper and lower flanges, further enhancing the sealing effect.

[0039] The annular bellows 6 can compensate for the length of the temperature sensor 1 under the condition of cold contraction. The specific principle is as follows: Since the inner tube 3 is in direct contact with the cryogenic liquid, it will experience cold contraction when it drops from room temperature to cryogenic temperature. The axial tensile displacement load A of the annular bellows 6 x The calculation formula is as follows:

[0040] A x =Lα(T max -T min ), (1)

[0041] In equation (1), L represents the pipe length in mm; α is the coefficient of thermal expansion of the pipe material in m / (m•℃); T max T represents the highest temperature in the pipeline.min The values ​​represent the saturation temperature of the medium being transported in the pipeline, all in °C. The annular corrugated pipe 6 has a relatively low elastic modulus, therefore, when the inner pipe experiences cold contraction, it can quickly compensate for the length, effectively preventing excessive stress on the adhesive part at the glue inlet 4, preventing displacement or detachment of the temperature sensor 1 during use, thus maintaining the internal vacuum, ensuring the normal working environment of the temperature sensor 1, and improving the stability and reliability of the measurement results.

[0042] In this embodiment, the size design of temperature sensor 1 is guided by the following formula:

[0043] Φ=Aλ(T h -T c ) / δ, (2)

[0044] In equation (2), Φ represents the heat conduction, A represents the cross-sectional area of ​​the temperature sensor, δ represents the length of the temperature sensor, and T h T represents ambient temperature. c Let λ represent the temperature of the cryogenic fluid, and λ be the thermal conductivity. The length and cross-sectional area of ​​temperature sensor 1 are adjusted according to the requirements of the actual application to achieve optimal heat transfer and measurement accuracy. For example, if it is necessary to reduce heat conduction, the length of temperature sensor 1 can be appropriately increased or its cross-sectional area decreased, or a material with lower thermal conductivity can be selected. Conversely, if it is necessary to increase heat conduction, the length of temperature sensor 1 can be appropriately decreased or its cross-sectional area increased, or a material with higher thermal conductivity can be selected. Through this precise calculation and design, temperature sensor 1 can provide accurate and reliable temperature measurement results in various complex application environments.

[0045] The aforementioned sensor arrangement can be used in cold boxes for refrigeration systems supporting superconducting power devices. The cold box is a key piece of equipment in superconducting technology applications, and its performance directly affects the stable operation and efficiency of the superconducting power device. To ensure the normal operation of the cold box, its cooling effect needs to be periodically monitored using temperature sensors. In traditional cold box inlet and outlet liquid nitrogen pipeline temperature sensor arrangements, the sensors are typically directly inserted into the liquid nitrogen pipeline. This arrangement cannot adjust the position of the temperature sensors according to actual needs, nor can it provide effective compensation for thermal contraction. These limitations may lead to inaccurate measurement results. Furthermore, most temperature sensors are connected by wires, which may cause them to be affected by buoyancy, resulting in them floating on the surface of the liquid nitrogen and failing to accurately measure the internal temperature of the liquid.

[0046] Using the temperature sensor arrangement structure proposed in Example 1, on the one hand, the adjustable connection structure located at the end of the temperature sensor near the inner tube allows for convenient adjustment of the sensor's orientation and angle according to the actual measurement environment and the target object's position, thereby ensuring the accuracy and reliability of the measurement results. On the other hand, the annular corrugated pipe can compensate for the length of the temperature sensor under cold contraction, avoiding excessive stress at the connection between the temperature sensor and the cover plate, achieving complete sealing of the temperature sensor, and further improving the accuracy and reliability of the measurement results. Furthermore, the guardrail and glue-injection groove structures effectively fix the temperature sensor, preventing displacement or detachment during use, thus maintaining the internal vacuum level, ensuring the normal operating environment of the temperature sensor, and improving the stability and reliability of the measurement results. Example 2

[0047] This embodiment provides a method for arranging temperature sensors for the inlet and outlet liquid nitrogen pipelines of a superconducting power device, based on the arrangement structure of the temperature sensors for the inlet and outlet liquid nitrogen pipelines of the cold box of the superconducting power device described in Embodiment 1, including the following steps:

[0048] S1. Weld the protective tube 9 to the outer tube 2, weld the protective tube 9 to the inner tube 3, and pass the temperature sensor 1 through the outer tube 2 and the inner tube 3 out of the protective tube 9.

[0049] S2. Weld one end of the annular corrugated pipe 6 to the bottom of the cover plate 11 and fix the other end to the end of the protective pipe 9 near the outer pipe 2. The end of the temperature sensor 1 near the outer pipe 2 passes through the glue injection port 4 set inside the cover plate 11 and the height of the end of the temperature sensor 1 near the inner pipe 3 is not higher than the liquid level height of the inner pipe 3.

[0050] S3. Adjust the installation angle of the temperature sensor 1 through the adjustable connection structure 10 until it meets the user's needs.

[0051] S4. After adjusting the angle, inject low-temperature adhesive into the injection port 4 to seal and fix the temperature sensor 1 to the cover plate 11. After injection, let it stand in the oven for 24 hours until the adhesive is completely dry, then perform a vacuum leak test. The vacuum leak rate should be better than 10%. -10 Pa·m 3 / S means the final placement of the temperature sensor is complete.

[0052] In the above process, a vacuum leak test must be performed after each welding, sealing, or fixing operation is completed, and the vacuum leak rate should be better than 10%. -10 Pa·m 3 The next step can only be performed when / S is activated.

[0053] The above method can adjust the installation angle of the temperature sensor while maintaining the internal vacuum level, and perform length compensation under cold contraction, ensuring that the temperature sensor 1 has a normal working environment and improving the stability and reliability of the measurement results. Furthermore, the method is simple to operate, facilitating subsequent replacement of the temperature sensor 1 to meet diverse application scenarios and practical needs.

Claims

1. A temperature sensor arrangement structure for the inlet and outlet liquid nitrogen pipelines of a cold box, characterized in that, It includes a temperature sensor (1), a low-temperature pipe, an annular corrugated pipe (6), a protective pipe (9), and a cover plate (11). The protective tube (9) is welded and fixed to the low-temperature pipeline, which includes an outer tube (2) and an inner tube (3). The temperature sensor (1) passes through the outer tube (2) and the inner tube (3) and exits from the protective tube (9). The cover plate (11) is provided with an injection port (4). The end of the temperature sensor (1) near the outer tube (2) passes through the injection port (4) and exits the cover plate (11). After the temperature sensor (1) exits the cover plate (11), low-temperature adhesive is injected into the injection port (4) to make the temperature sensor (1) and the cover plate (11) fit together. The temperature sensor (1) is sealed and fixed; the height of the end of the temperature sensor (1) near the inner tube (3) is not higher than the liquid level height of the inner tube (3); the end of the temperature sensor (1) near the inner tube (3) is provided with an adjustable connection structure (10) for adjusting the installation angle of the temperature sensor (1) in the circumferential direction; one end of the annular corrugated pipe (6) is welded and fixed to the bottom of the cover plate (11), and the other end is fixedly connected to the end of the protective pipe (9) near the outer tube (2); the annular corrugated pipe (6) is used to compensate the length of the temperature sensor (1) under the phenomenon of cold contraction.

2. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 1, characterized in that, The bottom of the glue injection port (4) is provided with a guardrail plate (5). One end of the guardrail plate (5) is fixedly connected to the bottom of the cover plate (11), and the other end is fixedly connected to the end of the annular corrugated pipe (6) near the cover plate (11). The guardrail plate (5) is provided with a through hole coaxial with the glue injection port (4). After the temperature sensor (1) passes through the through hole, glue is injected into the through hole to fix the temperature sensor (1) and the guardrail plate (5).

3. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 1, characterized in that, The bottom of the glue injection port (4) is provided with a glue injection groove (12), and the cross-sectional area of ​​the glue injection groove (12) is larger than the cross-sectional area of ​​the glue injection port (4).

4. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 1, characterized in that, One end of the annular corrugated pipe (6) is fixedly connected to the end of the protective pipe (9) near the outer pipe (2) by a flange. The flange includes an upper flange (7) and a lower flange (8). The upper flange (7) is welded and fixed to the annular corrugated pipe (6), and the lower flange (8) is welded and fixed to the protective pipe (9). The upper flange (7) and the lower flange (8) are connected by a snap fastener, and a sealing ring is provided between the upper flange (7) and the lower flange (8).

5. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 4, characterized in that, Matching bolts and nuts are provided between the upper flange (7) and the lower flange (8).

6. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 1, characterized in that, The cross-sectional area and length of the temperature sensor (1) are designed using the following formula: Φ=Aλ(T h -T c ) / d, Where Φ is the heat conduction, A is the cross-sectional area of ​​the temperature sensor, δ is the length of the temperature sensor, and T is the thermal conductivity. h For ambient temperature, T c λ represents the temperature of the cryogenic fluid and λ represents the thermal conductivity.

7. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 1, characterized in that, The adjustable connection structure (10) is a universal joint or an angle knob.

8. The arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines in a cold box according to claim 1, characterized in that, An epoxy fiberglass bracket is installed inside the protective tube (9), and the temperature sensor (1) is tightly fixed on the epoxy fiberglass bracket by spiral winding.

9. A method for arranging temperature sensors for inlet and outlet liquid nitrogen pipelines of a cold box based on the arrangement structure of temperature sensors for inlet and outlet liquid nitrogen pipelines as described in any one of claims 1-8, characterized in that, Includes the following steps: Weld the protective tube (9) to the low-temperature pipeline, and pass the temperature sensor (1) through the outer tube (2) and inner tube (3) out of the protective tube (9); weld one end of the annular corrugated pipe (6) to the bottom of the cover plate (11) and fix the other end to the end of the protective tube (9) near the outer tube (2); the end of the temperature sensor (1) near the outer tube (2) passes through the glue injection port (4) set inside the cover plate (11) and the height of the end of the temperature sensor (1) near the inner tube (3) is not higher than the liquid level height of the inner tube (3); The installation angle of the temperature sensor (1) is adjusted along the circumferential direction by the adjustable connection structure (10) until the user's needs are met. After the angle adjustment is completed, low-temperature adhesive is injected into the injection port (4) to seal and fix the temperature sensor (1) and the cover plate (11).

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