High-precision portable rapid calibration device of temperature sensor

Abstract

A high-precision portable rapid calibration device of a temperature sensor comprises a cavity, a composite wall layer and a top cover. Wherein the cavity accommodates heat conduction liquid of a high heat conduction material and heat insulation liquid of a low heat conduction material, and the standard thermometer and the temperature sensor to be calibrated penetrate through the heat insulation liquid and are immersed in the heat conduction liquid; the composite wall layer covers the periphery of the cavity and comprises a heat-conducting inner cylinder and a heat-conducting outer cylinder which are made of a high-heat-conductivity material, and a heat-insulating filler layer and a heat-insulating coating layer which are made of a low-heat-conductivity material; the top cover comprises an upper-layer top cover and a lower-layer top cover which are made of high-heat-conductivity materials and fixedly connected to the top ends of the heat-conducting inner cylinder and the heat-conducting outer cylinder to form a high-heat-conductivity path so as to achieve temperature uniformity of a heat-conducting liquid area, and the upper-layer top cover is provided with a temperature measuring sensor and a temperature control actuator so as to adjust and stably maintain the calibration temperature of heat-conducting liquid in the cavity. A temperature field which is stable, uniform, high in precision, flexible and adjustable is created in the device, and the device has the advantages of being simple in structure, low in cost, rapid to operate and convenient to carry and can be used for batch calibration of temperature sensors of a spacecraft high-precision temperature control system.

Description

Technical Field

[0001] This invention relates to the calibration of temperature sensors, specifically to a high-precision portable and rapid calibration device for temperature sensors, belonging to the field of precision temperature measurement technology. Background Technology

[0002] To achieve on-orbit temperature control, a satellite typically deploys hundreds of thermistors. With current technology, the temperature resolution of thermistors can reach 1 mK or even higher. However, the temperature-resistance relationship varies significantly between individual thermistors; at the same temperature, the temperature readings of different sensors can deviate by more than 300 mK. Therefore, consistency calibration is necessary during ground testing, especially for satellites with high-precision temperature control requirements, such as spacecraft conducting gravitational wave detection, where the consistency between temperature sensors must exceed 1 mK.

[0003] Existing temperature calibration methods mainly include the comparison method and the fixed-point method. The comparison method places the temperature sensor to be calibrated and a reference standard thermometer in the same stable and uniform environment. The ambient temperature is then adjusted to different stable values, while simultaneously recording the readings of the standard thermometer (the actual temperature) and the output signal of the sensor to be calibrated. This allows for multi-point calibration over a large temperature range. Its accuracy depends on the accuracy of the reference standard thermometer and the temperature uniformity of the calibration environment. The fixed-point method uses a substance with a known precise temperature (called a fixed-point substance, such as an ice-water mixture) as a standard. The temperature sensor to be calibrated is placed in the stable temperature environment of this substance, and calibration is performed by comparing the sensor readings with the actual temperature of the fixed-point substance. The fixed-point method can achieve sub-mK absolute accuracy, but it is complex, time-consuming, and can only obtain data from a single temperature point, making it unsuitable for establishing and calibrating the temperature-resistance curve of the temperature sensor. Therefore, the comparison method is more suitable for the temperature calibration of temperature sensors used in spacecraft.

[0004] In existing comparative calibration techniques, creating a stable, uniform temperature environment relies on a constant-temperature bath or chamber. The chamber is used to create an isothermal environment for the gas; however, gases have low heat capacity, poor thermal conductivity, and poor resistance to thermal disturbances and temperature uniformity, making it difficult to achieve mK-level temperature uniformity across the entire field under current technological conditions. Therefore, high-precision temperature calibration currently mainly relies on expensive, high-precision constant-temperature baths.

[0005] To ensure temperature stability in the liquid region, high-precision thermostatic baths contain a large amount of liquid, using the liquid's high heat capacity to suppress the effects of environmental thermal disturbances. To ensure temperature uniformity in the liquid region, the thermostatic baths often use a stirrer to circulate the liquid, ensuring thorough mixing of hot and cold fluids. For example, invention application CN 105758558 A discloses a "Calibration Device for a Thermistor Temperature Sensor," which includes a cold liquid bath filled with alcohol and a thermostatic expansion tank fixed above it. The lower half of the expansion tank is suspended in the cold liquid bath, while the upper half is tightly wrapped with an insulation layer. The thermistor temperature sensor to be calibrated and a standard platinum resistance thermometer are immersed in the alcohol in the expansion tank. The alcohol circulates between the expansion tank and the cold liquid bath through a cold liquid circulation pipe to create a uniform and stable temperature field. While this device can perform batch calibration of temperature sensors, ensuring a uniform and stable ambient temperature field and achieving high-precision calibration necessitates expanding the isothermal liquid area and employing circulation measures. This results in a complex and heavy calibration device, making it difficult to carry or frequently transport, and hindering on-site calibration operations. Furthermore, due to the large liquid area and high heat capacity, the temperature adjustment is slow, typically requiring 30 minutes to several hours to reach a steady-state temperature field, thus limiting rapid calibration and reducing work efficiency. Currently, a representative product on the market is the Fluke 6054 isothermal bath, which can achieve a temperature stability and uniformity of 5 mK within the test area, suitable for high-precision sensor calibration. However, such isothermal baths are not well-suited for efficient and rapid on-site calibration operations. Using smaller isothermal baths, such as the Fluke 6109A-P or 7109A-P, reduces the weight to 16-20 kg, but this usually results in insufficient calibration accuracy, reaching only about 100 mK. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-precision, portable, and rapid calibration device for temperature sensors. It creates a stable, uniform, and flexibly adjustable temperature field internally, which is suitable for rapid and accurate calibration of the temperature-resistance relationship of batches of thermistors. The calibration accuracy reaches better than 1 mK, so as to meet the needs of high-precision temperature control systems for spacecraft for temperature sensor calibration and achieve portability and low cost of the device.

[0007] Based on the above objectives, the technical solution provided by the present invention is as follows: A high-precision portable and quick calibration device for a temperature sensor includes: a central cavity extending from top to bottom, a composite wall layer surrounding the cavity from the bottom and four sides, and a top cover that is sealed and fixed to the top of the composite wall layer. The cavity is a cylindrical cavity with a closed bottom. The lower part contains a thermally conductive liquid, which is a high thermal conductivity material that is liquid at room temperature. The upper surface is covered with a thermally insulating liquid, which is a low thermal conductivity material with a lower density than the thermally conductive liquid and is not miscible with it. The thermally insulating liquid forms a thermal barrier and a chemical barrier between the thermally conductive liquid and the outside air, preventing thermal disturbances in the air from directly affecting the thermally conductive liquid and preventing the thermally conductive liquid from evaporating, oxidizing, or undergoing a chemical reaction. A standard thermometer and a temperature sensor to be calibrated are immersed in the thermally conductive liquid through the thermally insulating liquid for calibration. The composite wall layer includes a thermally conductive inner cylinder, a thermally insulating filler layer, a thermally conductive outer cylinder, and a thermally insulating covering layer arranged coaxially from the inside to the outside. The cavity is located inside the thermally conductive inner cylinder. The thermally conductive inner cylinder and the thermally conductive outer cylinder are made of high thermal conductivity materials and are closed at the bottom to rapidly conduct heat and achieve temperature uniformity between the inner and outer cylinders and the thermally conductive liquid area. The thermally insulating filler layer and the thermally insulating covering layer are made of low thermal conductivity materials and are closed at the bottom to block heat conduction and achieve temperature stability in the thermally conductive liquid area. The top cover includes an upper top cover and a lower top cover made of a high thermal conductivity material. The lower top cover is horizontally fixed to the top of the heat-conducting inner cylinder and the heat-conducting outer cylinder through a high thermal conductivity material. The upper top cover is stacked and fixedly attached to the upper surface of the lower top cover, so that the upper top cover, the lower top cover, the heat-conducting inner cylinder and the heat-conducting outer cylinder are connected to form an integral heat-conducting frame, which together form a high thermal conductivity path to achieve temperature uniformity in the heat-conducting liquid area. The upper top cover is equipped with interconnected temperature sensors and temperature control actuators. The temperature control actuators are energized to heat or cool to achieve closed-loop control of the top cover temperature, thereby regulating and stabilizing the set calibrated temperature of the heat-conducting liquid in the cavity. The temperature sensors are used to monitor the top cover temperature. The temperature control actuator is activated to heat or cool, so that the temperature of the heat-conducting liquid area can quickly reach and stabilize at the preset calibration temperature in a short time. The maximum temperature difference in the entire heat-conducting liquid area is controlled below 0.1 mK, thereby achieving uniformity and stability of the calibration temperature of the temperature sensor to be calibrated in the heat-conducting liquid.

[0008] Furthermore, a thermal connection interface is provided between the upper and lower top covers. A thermally conductive pad, thermal grease, or thermal insulation pad is selectively provided at this thermal connection interface to adjust the thermal resistance distribution in the top cover area and reduce the impact of the upper top cover on the temperature uniformity and stability of the lower top cover.

[0009] Furthermore, the quick calibration device also includes a clamp for accommodating and fixing a standard thermometer and several temperature sensors to be calibrated. The clamp is placed in the cavity so that the temperature sensing parts of the standard thermometer and all the temperature sensors to be calibrated are in close proximity to each other after being immersed in the heat-conducting liquid, thus having a similar temperature environment.

[0010] Furthermore, the thermal conductivity of the heat-conducting liquid is not less than 10 W / (m·K), and the thermal conductivity of the heat-insulating liquid is less than 1 W / (m·K). K).

[0011] Furthermore, the materials used in the heat-conducting liquid include, but are not limited to, gallium-based liquid alloys; the materials used in the heat-insulating liquid include, but are not limited to, silicone oil and mineral oil; the materials used in the heat-conducting inner cylinder, heat-conducting outer cylinder, upper top cover, and lower top cover include, but are not limited to, metals, alloys, diamond, and heat-conducting graphene; the heat-insulating materials used in the heat-insulating filler layer and heat-insulating covering layer include, but are not limited to, foam, sponge, and aerogel; the high thermal conductivity material connecting the lower top cover to the heat-conducting inner cylinder and heat-conducting outer cylinder is thermally conductive silicone grease; the elements used in the temperature sensing sensor include, but are not limited to, thermistors, platinum resistance thermometers, and thermocouples; and the devices used in the temperature control actuator include, but are not limited to, heaters and thermoelectric coolers.

[0012] Compared with the prior art, the present invention achieves the following beneficial effects: (1) Liquid metal and other high thermal conductivity liquid materials are used to replace conventional liquid working fluid. At the same time, a composite wall layer with alternating thermal conductivity and thermal insulation materials is set up, and the thermal conductivity wall layer is connected to the top cover to form an integral thermal conductivity frame, forming a high thermal conductivity path. Only the top cover is allowed to have a heat exchange effect with the outside world, thus constructing a fast thermal conductivity path with the thermal conductivity top cover as the only heat flow hub. This makes the heat leakage power of the thermal conductivity inner cylinder in the side and bottom positions very small, and the temperature gradient is also reduced accordingly. The temperature difference between the inner and outer cylinders is extremely small, thereby improving the temperature consistency of the thermal conductivity liquid area and providing a uniform thermal environment for calibration. At the same time, the high thermal conductivity of the thermal conductivity path enables the thermal conductivity liquid to quickly reach a stable calibration temperature in a short time, thus creating favorable conditions for quickly completing the high-precision calibration of the temperature sensor.

[0013] (2) Thanks to the fast and high thermal conductivity path and the high thermal conductivity of the heat-conducting liquid, the device of the present invention only needs a single temperature control circuit to control the temperature of the top cover, and can simultaneously achieve the temperature uniformity control of the heat-conducting inner cylinder, the heat-conducting outer cylinder and the heat-conducting liquid, which reduces the complexity of the temperature control system. At the same time, it can achieve temperature uniformity better than 1 mK without relying on moving parts such as stirrers to form forced convection. Therefore, the device is further simplified, the size and weight of the device are reduced, the total heat capacity is reduced, thereby simplifying the device structure, reducing the device cost, and greatly improving the portability, reliability and temperature regulation sensitivity of the device. In summary, this invention improves the consistency and stability of temperature in the heat-conducting liquid region, enhances calibration accuracy, and achieves a uniform (better than 1 mK), flexible, adjustable, stable, and reliable calibration temperature. It has the advantages of simple structure, low cost, quick operation, and portability, and can be used for batch calibration of temperature sensors in high-precision temperature control systems for spacecraft. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of the structure of the present invention.

[0015] Figure 2 This is a perspective view of the present invention.

[0016] Figure 3 This is a three-dimensional dimensional diagram of the present invention.

[0017] Figure 4 Temperature distribution map of the liquid metal (thermal conductive liquid) region after 1500 seconds of controlled heating.

[0018] Figure 5 This is a time-temperature change curve of a monitoring feature point within the liquid column.

[0019] Figure 6 for Figure 5 A magnified view of the area at time 1500.

[0020] Figure 7 This is a schematic diagram illustrating the time change of the maximum temperature difference within the liquid column.

[0021] In the picture, 1—Cavity, 2—Heat-conducting inner cylinder, 3—Heat-conducting outer cylinder, 4—Heat-insulating filler layer, 5—Heat-insulating covering layer, 6—Lower top cover, 7—Upper top cover, 8—Heat-conducting liquid, 9—Heat-insulating liquid, 10—Sensor clamp, 11—Temperature control actuator, 12—Temperature sensor, 13—Thermal connection interface. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the scope of protection of the present invention.

[0023] This invention is used for the calibration of temperature sensors, and is especially suitable for the rapid batch calibration of temperature sensors in high-precision temperature control systems for spacecraft.

[0024] Please refer to the following: Figure 1 and Figure 2 The high-precision portable quick calibration device for the temperature sensor consists of a cavity 1 from top to bottom, a composite wall layer surrounding the cavity 1, and a top cover.

[0025] The cavity 1, located in the center of the device, is a cylindrical cavity with a closed bottom and contains a thermally conductive liquid 8. This thermally conductive liquid 8 is a highly thermally conductive material that is liquid at room temperature, with a thermal conductivity of not less than 10 W / (m·K), such as, but not limited to, gallium-based liquid alloys. A thermally insulating liquid 9, with a thermal conductivity of less than 1 W / (m·K), covers the thermally conductive liquid 8. The insulating liquid 9, with a density less than that of the thermally conductive liquid 8 and not miscible with it, can be made of materials such as silicone oil or mineral oil. It forms a thermal and chemical barrier between the thermally conductive liquid 8 and the external air, preventing thermal disturbances in the air from directly affecting the thermally conductive liquid 8, and also preventing losses such as evaporation or oxidation, or chemical reactions. A standard thermometer and the temperature sensor to be calibrated are immersed in the thermally conductive liquid 8 for calibration.

[0026] The composite wall layer is located at the bottom and outer periphery of the four sides of the cavity 1, and from the inside out includes: a heat-conducting inner cylinder 2, a heat-insulating filler layer 4, a heat-conducting outer cylinder 3, and an outermost heat-insulating covering layer 5. The heat-conducting inner cylinder 2 and the heat-conducting outer cylinder 3 in the composite wall layer can be made of metals, alloys, diamond, heat-conducting graphene, etc., to rapidly conduct heat within the heat conduction path, thereby achieving uniform temperature in the heat-conducting liquid area. The heat-insulating filler layer 4 and the heat-insulating covering layer 5 in the composite wall layer can be made of foam, sponge, aerogel, etc., to block heat conduction from the heat-conducting liquid area to the outside, ensuring the temperature stability of the heat-conducting liquid area. The temperature of the heat-conducting liquid area refers to the temperature field formed by all the heat-conducting liquid 8 within the occupied space area of ​​the cavity 1.

[0027] The top cover comprises two layers: an upper top cover 7 and a lower top cover 6. A temperature sensor 12 and a temperature control actuator 11 are arranged on the upper top cover 7. The temperature control actuator 11 is energized to generate heat or cool, thereby achieving closed-loop control of the top cover temperature and adjusting and maintaining the calibrated temperature of the heat-conducting liquid 8 within the cavity 1. The temperature sensor 12 is used to monitor the top cover temperature and may be of types including, but not limited to, thermistors, platinum resistance thermometers, and thermocouples. The temperature control actuator 11 may be of types including, but not limited to, heaters and thermoelectric coolers.

[0028] A thermal connection interface 13 is provided between the upper top cover 7 and the lower top cover 6 of the top cover. By selectively setting a thermal conductive pad, thermal conductive grease or thermal insulation pad at the thermal connection interface 13, the thermal resistance distribution of the top cover area can be adjusted, thereby reducing the influence of the temperature of the upper top cover 7 on the temperature uniformity and stability of the lower top cover 6.

[0029] The lower top cover 6 is fixed to the heat-conducting inner cylinder 2 and the heat-conducting outer cylinder 3 by a high thermal conductivity material, so that the upper top cover 7, the lower top cover 6, the heat-conducting inner cylinder 2, and the heat-conducting outer cylinder 3 form an integral and continuous heat-conducting frame, which together constitutes a high thermal conductivity path. The temperature uniformity along this heat-conducting path is good, and the temperature difference between the heat-conducting inner cylinder 2 and the heat-conducting outer cylinder 3 is small. Therefore, the heat leakage power of the heat-conducting inner cylinder 2 is small, and the temperature gradient between the heat-conducting inner cylinder 2 and the heat-conducting liquid 8 inside it is small, ensuring the temperature uniformity of the heat-conducting liquid 8.

[0030] The calibration device also includes a clamp for accommodating and fixing a standard thermometer and multiple temperature sensors to be calibrated, so that the temperature sensing parts of the standard thermometer and all the temperature sensors to be calibrated are in close proximity to each other after being placed in the heat-conducting liquid 8 in the cavity 1 of the device, thus having a similar temperature environment.

[0031] Thanks to the above-mentioned heat conduction path, the device only needs a single temperature control circuit to control the temperature of the top cover, and can simultaneously control the temperature of the heat-conducting outer cylinder 3, the heat-conducting inner cylinder 2 and the heat-conducting liquid 8, thus reducing the complexity of the temperature control system.

[0032] Thanks to the above-mentioned heat conduction path and the high thermal conductivity of the heat conduction liquid 8 inside the device, the heat conduction liquid area can achieve a temperature uniformity better than 1 mK without relying on moving parts such as stirrers to form forced convection. Therefore, the structure of the device is further simplified, the required size and weight of the device are reduced, and the portability, reliability and temperature regulation sensitivity of the system are improved.

[0033] Example The calibration device described in this embodiment has the structure as described above. The thermally conductive liquid 8 is Thermal GtizzlyConductonaut liquid metal thermal paste, which is a eutectic alloy of metals such as gallium, tin, and indium, with a thermal conductivity of 73 W / (m·K) and a density of 6240 kg / m³. The insulating liquid 9 is dimethyl silicone oil, with a density of 970 kg / m³ and a thermal conductivity of 0.015 W / (m·K).

[0034] The upper top cover 7, the lower top cover 6, the heat-conducting inner cylinder 2, and the heat-conducting outer cylinder 3 are all made of copper, with a thermal conductivity of 398 W / (m·K) and a density of 8900 kg / m³. 3Both the insulation filler layer 4 and the insulation covering layer 5 are made of foam with a density of 30 kg / m³ and a thermal conductivity of 0.03 W / (m·K). The thermal connection interface 13 between the upper top cover 7 and the lower top cover 6 is connected by a 1 mm thick PTFE insulation pad with a thermal conductivity of 0.2 W / (m·K). The lower top cover 6 is connected to the heat-conducting inner cylinder 2 and the heat-conducting outer cylinder 3 using thermally conductive silicone grease, with a contact heat transfer coefficient of approximately 1000 W / (m²·K).

[0035] The temperature sensor 12, which measures the temperature of the upper cover 7 and the lower cover 6, is a thermistor with a temperature measurement accuracy of 1 mK. The temperature control actuator 11, which controls the temperature of the cover, is a heating element, and the temperature control method is a switching control method with a switching frequency of 1 Hz.

[0036] The dimensions of the calibration device are as follows: Figure 3 As shown, the overall envelope is a cylinder with a diameter of 170 mm and a height of 240 mm, and the total mass is only 7.6 kg. The cavity 1 has a diameter of 20 mm, allowing at least 20 thermistors (sensors to be calibrated) with a cross-section no larger than a diameter of 3 mm to be arranged simultaneously at the same height. The temperature uniformity and thermal stability of the calibration device described in this embodiment were verified through numerical simulation during operation.

[0037] The initial temperature of the calibration device is 20°C, and the installation environment is set to room temperature. The ambient air temperature in the +Y and +Z directions of the device is 20°C. See [link / reference]. Figure 3 The ambient air temperature in the -Y and -Z directions is 21℃, and the temperature environment exhibits sinusoidal fluctuations of ±0.3 K@ 1~10 mHz.

[0038] Temperature controller 11 is activated to perform closed-loop temperature control on the upper top cover 7 and the lower top cover 6. The target temperature is set to 25°C, and the heater power is set to 50 W for the first 14 minutes and then to 2 W. After 1500 seconds of heating, the temperature distribution in the entire liquid metal (thermal conductive liquid 8) region is as follows: Figure 4 As shown, the maximum temperature difference in the liquid metal (thermal conductive liquid 8) region is 0.6 mK.

[0039] A 20 mm high column of liquid metal (thermally conductive liquid 8) was taken from the bottom. Six characteristic points were recorded within the column (the center points of the bottom and top surfaces, the point of maximum Y-coordinate, and the point of minimum Y-coordinate) for monitoring. The temperature change curves at each characteristic point within the recorded liquid column are shown below. Figure 5 and Figure 6 As shown, the temperature reached approximately 25℃ within 900 seconds, and the temperature difference between the monitoring points was very small. At 1500 seconds, the temperature difference between the three monitoring points at the same altitude was no greater than 0.01℃. ,See Figure 6Within a plane with a height difference of 20mm, the maximum temperature difference shall not exceed 0.08. This means that the temperature uniformity within the captured liquid column is better than 0.1 mK, and the temperature gradient is less than 0.004. The variation of the maximum temperature difference between all characteristic points within the intercepted liquid column over time is shown in the figure. Figure 7 As shown, the maximum temperature difference drops below 1 mK after 900 s and below 0.1 mK after 1500 s.

[0040] Therefore, the verification results show that the calibration device of the present invention can stabilize the temperature of the thermally conductive liquid region (liquid metal region) used to immerse the sensor to be calibrated within a short period of 20-30 minutes, and the maximum temperature difference within the region is controlled below 0.1 mK, ensuring the stability and consistency of the temperature within the calibration region. Thus, the calibration device of the present invention achieves a stable, uniform, and flexibly adjustable temperature field internally, with a calibration accuracy of up to and better than 1 mK. This makes it suitable for the batch, rapid, and accurate calibration of thermistor temperature sensors for spacecraft, and it has the advantages of simple structure, portability, flexibility, and high accuracy and reliability.

[0041] This invention is not limited to the above embodiments. Any improvements and modifications made by those skilled in the art based on the teachings of this invention without departing from the scope of this invention should be within the protection scope claimed by this invention.

Claims

1. A high-precision, portable, and rapid calibration device for a temperature sensor, characterized in that: The aforementioned quick calibration device includes: a central cavity extending from top to bottom, a composite wall layer surrounding the cavity from the bottom and four sides, and a top cover that is sealed and fixed to the top of the composite wall layer; The cavity is a cylindrical cavity with a closed bottom. The lower part contains a thermally conductive liquid, which is a high thermal conductivity material that is liquid at room temperature. The upper surface is covered with a thermally insulating liquid, which is a low thermal conductivity material with a lower density than the thermally conductive liquid and is not miscible with it. The thermally insulating liquid forms a thermal barrier and a chemical barrier between the thermally conductive liquid and the outside air, preventing thermal disturbances in the air from directly affecting the thermally conductive liquid and preventing the thermally conductive liquid from evaporating, oxidizing, or undergoing a chemical reaction. A standard thermometer and a temperature sensor to be calibrated are immersed in the thermally conductive liquid through the thermally insulating liquid for calibration. The composite wall layer includes a thermally conductive inner cylinder, a thermally insulating filler layer, a thermally conductive outer cylinder, and a thermally insulating covering layer arranged coaxially from the inside to the outside. The cavity is located inside the thermally conductive inner cylinder. The thermally conductive inner cylinder and the thermally conductive outer cylinder are made of high thermal conductivity materials and are closed at the bottom to rapidly conduct heat and achieve temperature uniformity between the inner and outer cylinders and the thermally conductive liquid area. The thermally insulating filler layer and the thermally insulating covering layer are made of low thermal conductivity materials and are closed at the bottom to block heat conduction and achieve temperature stability in the thermally conductive liquid area. The top cover includes an upper top cover and a lower top cover made of a high thermal conductivity material. The lower top cover is horizontally fixed to the top of the heat-conducting inner cylinder and the heat-conducting outer cylinder through a high thermal conductivity material. The upper top cover is stacked and fixedly attached to the upper surface of the lower top cover, so that the upper top cover, the lower top cover, the heat-conducting inner cylinder and the heat-conducting outer cylinder are connected to form an integral heat-conducting frame, which together form a high thermal conductivity path to achieve temperature uniformity in the heat-conducting liquid area. The upper top cover is equipped with interconnected temperature sensors and temperature control actuators. The temperature control actuators are energized to heat or cool to achieve closed-loop control of the top cover temperature, thereby regulating and stabilizing the set calibrated temperature of the heat-conducting liquid in the cavity. The temperature sensors are used to monitor the top cover temperature. The temperature control actuator is activated to heat or cool, so that the temperature of the heat-conducting liquid area can quickly reach and stabilize at the preset calibration temperature in a short time. The maximum temperature difference in the entire heat-conducting liquid area is controlled below 0.1 mK, thereby achieving uniformity and stability of the calibration temperature of the temperature sensor to be calibrated in the heat-conducting liquid.

2. The high-precision portable and rapid calibration device for temperature sensors according to claim 1, characterized in that: A thermal connection interface is provided between the upper and lower top covers. A thermally conductive pad, thermal grease, or thermal insulation pad is selectively provided at the thermal connection interface to adjust the thermal resistance distribution in the top cover area and reduce the impact of the upper top cover on the temperature uniformity and stability of the lower top cover.

3. The high-precision portable and rapid calibration device for temperature sensors according to claim 1, characterized in that: The aforementioned quick calibration device also includes a clamp for accommodating and fixing a standard thermometer and several temperature sensors to be calibrated. The clamp is placed in the cavity, so that the temperature sensing parts of the standard thermometer and all the temperature sensors to be calibrated are in close proximity to each other after being immersed in the heat-conducting liquid, thereby having a similar temperature environment.

4. The high-precision portable and rapid calibration device for temperature sensors according to claim 1, characterized in that: The thermal conductivity of the heat-conducting liquid is not less than 10 W / (m·K), and the thermal conductivity of the heat-insulating liquid is less than 1 W / (m·K). K).

5. The high-precision portable and rapid calibration device for temperature sensors according to claim 1, characterized in that: The materials used in the heat-conducting liquid include, but are not limited to, gallium-based liquid alloys; the materials used in the heat-insulating liquid include, but are not limited to, silicone oil and mineral oil; the materials used in the heat-conducting inner cylinder, heat-conducting outer cylinder, upper top cover, and lower top cover include, but are not limited to, metals, alloys, diamond, and heat-conducting graphene; the heat-insulating materials used in the heat-insulating filler layer and heat-insulating covering layer include, but are not limited to, foam, sponge, and aerogel; the high thermal conductivity material connecting the lower top cover to the heat-conducting inner cylinder and heat-conducting outer cylinder is thermally conductive silicone grease; the elements used in the temperature sensing sensor include, but are not limited to, thermistors, platinum resistance thermometers, and thermocouples; and the devices used in the temperature control actuator include, but are not limited to, heaters and thermoelectric coolers.

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