An ultrasonic temperature sensor calibration device

Abstract

This invention belongs to the field of temperature sensor measurement and calibration equipment, and is an ultrasonic temperature measurement type temperature sensor calibration device. It aims to address the shortcomings of existing technologies and the technical gaps between existing technologies and the seven technical expectations for temperature sensor calibration devices. This invention establishes a set temperature in a constant temperature chamber, adjusts the gas supply unit, thermal balancer, and temperature-controlled heater, and then uses monitoring by a thermal balance detector and measurement by an ultrasonic thermometer to determine the calibration standard temperature of the ideal gas within the constant temperature chamber. From this, the measurement error between the temperature measured by the temperature sensor under test and the calibration standard temperature is determined. Repeating the above process yields the measurement error and correction curve of the temperature sensor under test at various calibration standard temperatures. This invention has the following characteristics: a wide calibrable temperature range, high temperature accuracy, multiple calibrable standard temperature points, simultaneous calibration of multiple and various temperature sensors, and a programmable calibration operation process.

Description

Technical Field

[0001] This invention belongs to the field of temperature sensor measurement and calibration equipment, specifically an ultrasonic temperature measurement type temperature sensor calibration device. Background Technology

[0002] Temperature sensors or thermometers are instruments used to measure the temperature of gases, liquids, solids, and ambient temperatures. They are widely used in many fields and applications, such as semiconductor material preparation and processing, chip fabrication and processing, biomaterial preparation and processing, medical supply storage and transportation, food processing, pharmaceutical processing, fine chemicals, medical facilities, and laboratories. These applications require strict temperature monitoring and control, necessitating the accurate measurement of temperature values ​​by the temperature sensor. However, accurate temperature measurement depends on rigorous calibration. Therefore, calibrating the accuracy of the temperature sensor is a crucial technical requirement. This necessitates a temperature sensor calibration device to evaluate and determine the sensor's temperature range and accuracy, and to obtain calibration data or calibration curves. With the advancement of temperature measurement technology and temperature sensor calibration devices, the industry has the following technical expectations for temperature sensor calibration devices:

[0003] (1) Wide detectable temperature range (e.g., measurable temperature range is -150℃ to 1800℃).

[0004] (2) The verifiable temperature accuracy is high (for example, the measurable temperature accuracy is above 99.99%, or the measurement error of the measurable temperature is less than ℃).

[0005] (3) There are many standard temperature points that can be verified (for example, more than 50 standard temperature points can be measured).

[0006] (4) The verifiable standard temperature point is formed quickly and stably;

[0007] (5) It can calibrate a variety of temperature sensors (e.g., platinum resistance temperature sensors, thermocouple temperature sensors, semiconductor temperature sensors, heat pipe temperature sensors, gas temperature sensors, mercury temperature sensors, ultrasonic temperature sensors, etc.).

[0008] (6) Multiple temperature sensors can be calibrated simultaneously (for example, more than 30 temperature sensors can be calibrated at a time).

[0009] (7) The verification process is procedural, controllable, and easy to operate.

[0010] However, existing technologies have not yet met the aforementioned seven technical expectations for temperature sensor calibration devices.

[0011] The invention patent CN111811693.A, entitled "An Automatic Verification Method for a Standard Platinum Resistance Thermometer," is characterized by an automatic verification device for a standard platinum resistance thermometer, comprising a computer, a precision temperature measuring bridge, a selector switch, a flexible gripping device, an annealing furnace, a metal fixing point device, a water triple point bottle, and a standard platinum resistance thermometer. The precision temperature measuring bridge measures the resistance value of the standard platinum resistance thermometer under test. The selector switch switches the connection between different standard platinum resistance thermometers and the precision temperature measuring bridge. The flexible gripping device automates the process by gripping the standard platinum resistance thermometer. The metal fixing point device and the water triple point bottle reproduce the fixed point temperature defined by ITS-90. The computer controls the metal fixing point device to reproduce the temperature plateau, controls the flexible gripping device's operation, switches the selector switch channels, controls the precision temperature measuring bridge to acquire data, and records and processes the data. During operation, the thermometers under test are arranged in numerical order in the waiting area, and their terminals are connected to the respective channels of the selector switch. At the start of the calibration, a computer-controlled flexible gripping device removes the standard platinum resistance thermometer to be tested from the waiting area and places it into the temperature measuring trap of the fixed-point device. The computer then controls a precision temperature measuring bridge to measure the resistance value of the standard platinum resistance thermometer. The computer automatically reads the value based on preset criteria to determine if the reading conditions are met. After the measurement is completed, the computer controls the flexible gripping device to remove the thermometer from the temperature measuring trap of the fixed-point device and send it to the next waiting area. This process is repeated until all measurements are completed. The computer analyzes and processes the collected data and automatically generates the calibration record. The entire data collection process is automated, saving manpower. Although the standard platinum resistance thermometer calibration system described in publication number CN111811693.A achieves automatic displacement of the tested standard platinum resistance thermometer, automatic acquisition and processing of calibration data, and automatic generation of calibration records, and has a relatively wide calibrable temperature range (-189℃~666℃) and relatively high calibrable temperature accuracy (based on the JJG160-2007 standard platinum resistance thermometer calibration procedure), it still has shortcomings compared to the seven technical expectations of temperature sensor calibration devices. Specifically, the calibrable temperature range of this standard platinum resistance thermometer calibration device is not wide enough; the calibrable temperature accuracy is still... The accuracy is not high enough; the number of verifiable standard temperature points is limited to only three: the freezing point of zinc, the freezing point of tin, and the triple point of water; it is difficult to quickly and stably establish verifiable standard temperature points, as the preparation of zinc freezing point preservation devices, tin freezing point preservation devices, and water triple point preservation devices is highly technical, and the temperature control required to achieve the freezing point of zinc, tin, and water triple point is very difficult, leading to persistent doubts about its reliability within the industry; it can only verify standard platinum resistance thermometers and cannot verify other types of temperature sensors; the number of temperature sensors that can be verified simultaneously is limited, allowing only a few temperature sensors to be verified at a time.

[0012] The patent CN211147898.U, entitled "Standard Platinum Resistance Thermometer Verification System," is a system for verifying standard platinum resistance thermometers. Its technical features include: using zinc freezing point preservation devices, tin freezing point preservation devices, and water triple point preservation devices as standard temperature points; using a temperature measuring bridge as the basis for determining the resistance of the standard platinum resistance thermometer under test; using JJG 160-2007 Standard Platinum Resistance Thermometer Verification Procedure as the evaluation basis; and using an electronic switch as the selection switch for evaluating a specific standard platinum resistance thermometer. Although this standard platinum resistance thermometer verification system has a relatively wide temperature detection range (-189℃ to 666℃) and relatively high temperature measurement accuracy (based on JJG 160-2007), it does not meet the technical requirements of standard platinum resistance thermometers. Based on the 160-2007 standard verification procedure for platinum resistance thermometers, this system still has shortcomings compared to the seven technical expectations for temperature sensor verification devices. These shortcomings include: an insufficiently wide measurable temperature range; insufficiently high measurable temperature accuracy; a limited number of measurable temperature points (only three: zinc freezing point, tin freezing point, and water triple point), and the highly technical preparation of the zinc, tin, and water triple point preservation devices, which are difficult to control, leading to consistent industry skepticism regarding their reliability; limited ability to verify multiple temperature sensors (only applicable to standard platinum resistance thermometers, not other types); a limited number of temperature sensors that can be verified simultaneously (only a few at a time); and a lack of procedural, controllable, and user-friendly verification procedures.

[0013] Given the shortcomings of existing temperature sensor calibration devices, especially the significant gap between them and the seven technical requirements for temperature sensor calibration devices, this application aims to address this issue. Summary of the Invention

[0014] To address the shortcomings of existing technologies and the technical gaps between existing technologies and the seven technical expectations for temperature sensor calibration devices, this invention proposes an ultrasonic temperature measurement type temperature sensor calibration device, the technical solution of which is as follows:

[0015] A constant-temperature chamber is established to house an ideal gas, is insulated from the outside, and is used to calibrate the temperature sensor under test. An interface is installed on the chamber wall to allow insertion of the temperature sensor. A gas supply unit with inlet and outlet interfaces is installed, supplying the chamber with ideal gas at room temperature or different low temperatures. This gas supply unit works in conjunction with a temperature-controlled heater and a thermal balancer within the chamber to create a series of standard calibration temperatures for the ideal gas. To ensure the ideal gas in the chamber quickly reaches thermal equilibrium, i.e., to rapidly achieve uniform temperature distribution, a drive mechanism is installed within the chamber. A thermal balancer is used to rapidly achieve thermal equilibrium for the ideal gas inside the constant-temperature chamber. A temperature-controlled heater is installed inside the chamber to regulate the degree of temperature rise of the ideal gas. A thermal balance detector is installed outside the chamber to determine if the ideal gas is in thermal equilibrium. An ultrasonic thermometer is installed outside the chamber to calibrate the temperature sensor under test. This ultrasonic thermometer detects the temperature of the ideal gas in thermal equilibrium based on ultrasonic principles. When the thermal balance detector determines that the ideal gas has reached thermal equilibrium, the ultrasonic measurement is activated. A thermometer measures the temperature of the ideal gas inside the constant temperature chamber, which serves as the calibration standard temperature for the temperature sensor under test. A control computer, equipped with an ultrasonic transducer monitoring circuit and capable of data monitoring, is installed outside the constant temperature chamber. This control computer performs the following operations to calibrate the temperature sensor under test: To achieve a set temperature in the constant temperature chamber, the gas supply unit, thermal balancer, and temperature-controlled heater are adjusted. Monitoring by the thermal balance detector indicates that the ideal gas inside the constant temperature chamber has reached thermal equilibrium at the set temperature. Then, monitoring by the ultrasonic thermometer indicates the ideal gas temperature at this thermal equilibrium. The temperature is used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test and comparing it with the calibration standard temperature, the measurement error of the temperature sensor under test and the calibration standard temperature is known. The above steps are repeated many times, that is, a series of ideal gas set temperatures are adjusted in a constant temperature chamber and the ultrasonic thermometer is monitored to obtain a series of ideal gas set temperatures. These set temperatures are used as the calibration standard temperatures of each level of the temperature sensor under test. At the same time, the temperature measured by the temperature sensor under test at each level of calibration standard temperature is collected. Thus, the measurement error, correction data and correction curve of the temperature sensor under test at each level of calibration standard temperature are obtained.

[0016] This invention includes a constant temperature chamber, a test instrument interface, a gas supply unit, a thermal balancer, a temperature-controlled heater, a thermal balance detector, an ultrasonic thermometer, and a control computer. The constant temperature chamber is a rigid container that holds ideal gas, calibrates the temperature sensor under test, and is strictly insulated from the outside. The test instrument interface is located on the wall of the constant temperature chamber and allows the probe of the temperature sensor under test to be inserted into the chamber from the outside. The gas supply unit is a combined device with the constant temperature chamber, having airflow inlet and outlet interfaces. The gas supply unit can supply ideal gas at room temperature or different low temperatures to the constant temperature chamber. It works in conjunction with the temperature-controlled heater and the thermal balancer to create various calibration standard temperatures for the ideal gas within the constant temperature chamber. The thermal balancer is a driving device that rapidly brings the ideal gas within the constant temperature chamber to thermal equilibrium. The temperature-controlled heater is a device that provides temperature-controlled heating for the ideal gas within the constant temperature chamber. The thermal balance detector is a detection device that checks whether the ideal gas within the constant temperature chamber is in thermal equilibrium. The ultrasonic thermometer is a detection device that uses the ultrasonic principle to detect the temperature of an ideal gas in a constant temperature chamber. When the heat balance detector determines that the ideal gas in the constant temperature chamber has reached thermal equilibrium, the ultrasonic thermometer is activated to measure the temperature of the ideal gas in the constant temperature chamber, which is then used as the calibration standard temperature for calibrating the temperature sensor under test. The control computer is an industrial control computer with an ultrasonic transducer monitoring circuit and the ability to perform data monitoring. The control computer performs the following calibration operation: by adjusting the gas supply unit, heat balancer, and temperature control heater to a certain set temperature, the heat balance detector determines that the ideal gas in the constant temperature chamber has reached thermal equilibrium, the ultrasonic thermometer measures the temperature of the ideal gas in the constant temperature chamber under this thermal equilibrium, and this temperature is used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test under this thermal equilibrium and comparing it with the calibration standard temperature, the measurement error between the temperature measured by the temperature sensor under test and the calibration standard temperature is obtained.

[0017] The constant temperature chamber is a horizontally placed cylindrical rigid container with a lid and a bottom. The walls of the chamber have a three-layer structure: an inner layer of fire-resistant, low-thermal-conductivity non-metallic material, a middle layer of vacuum insulation, and an outer layer of metallic material. A heat balance detector and an ultrasonic transducer are installed on the upper part of the outer wall of the lid. The upper part of the inner wall of the bottom is polished, serving as a reflective surface for the ultrasonic transducer. Several test port numbers are installed on the top of the side wall of the chamber to house temperature sensors. A heat balancer and a temperature-controlled heater are installed on the bottom of the side wall. A pressure gauge is installed inside the chamber to monitor the pressure of the ideal gas within.

[0018] The gas supply unit, along the gas flow direction, sequentially connects the gas tank inlet pipe, the gas tank, the gas tank outlet pipe, the refrigeration chamber, the refrigeration chamber exhaust pipe, and the airflow shower. The gas tank inlet pipe is equipped with a constant temperature chamber exhaust valve and a gas tank inlet valve. The gas tank outlet pipe is equipped with a gas tank outlet valve, a blower, and a refrigeration chamber inlet valve. The refrigeration chamber exhaust pipe is equipped with a refrigeration chamber exhaust valve and a constant temperature chamber inlet valve. The inlet end of the gas tank inlet pipe is connected to the constant temperature chamber. The airflow shower is located inside the constant temperature chamber and sprays airflow into the chamber in a multi-hole, dispersed manner. Inside the refrigeration chamber, the refrigeration unit... The evaporator of the refrigeration unit cools the ideal gas in the refrigeration chamber. The refrigeration chamber is equipped with a refrigeration chamber thermometer and a refrigeration chamber pressure gauge to monitor the temperature and pressure of the ideal gas in the refrigeration chamber. The exhaust valve of the refrigeration chamber and the exhaust valve of the constant temperature chamber are both electric regulating valves, which can adjust the airflow of the refrigeration chamber exhaust pipe and the gas tank inlet pipe. The gas tank inlet valve, the gas tank outlet valve, the refrigeration chamber inlet valve and the constant temperature chamber inlet valve are all electric shut-off valves that open or close. The blower is a fluid drive device that pressurizes the ideal gas from the gas tank outlet pipe and delivers it to the refrigeration chamber.

[0019] The heat balancer is an electric stirrer, and the part located in the constant temperature chamber, including the stirring blades, is made of non-metallic materials with refractory properties and poor thermal conductivity; the temperature control heater is an electric heater, made of non-metallic materials with refractory properties and poor thermal conductivity.

[0020] The ultrasonic thermometer and the thermal balance detector are the same device, differing only in their function and purpose. The ultrasonic thermometer consists of several ultrasonic transducers arranged in a ring, with another ultrasonic transducer located in the central area of ​​the ring. The sound waves emitted directly from the ring-shaped ultrasonic transducers onto the reflective surface inside the constant temperature chamber surround the probes of all the temperature sensors under test within the chamber, without being blocked by the sensors themselves. The thermal balance detector determines that the ideal gas inside the constant temperature chamber has reached thermal equilibrium only when the temperature difference measured by the several ultrasonic transducers is less than the maximum allowable temperature difference. At thermal equilibrium, the ultrasonic thermometer uses the average value of the temperatures measured by these transducers as the thermal equilibrium temperature or the calibration standard temperature. To prevent the operating temperature of the transducer ceramic oscillator from exceeding its tolerance temperature, the ultrasonic thermometer is equipped with a cooling water jacket. The cooling water jacket allows room temperature water to flow in and out, cooling or heating the ultrasonic transducer to ensure that the ultrasonic transducer 33 operates within its tolerance temperature range.

[0021] The ultrasonic transducer includes transducer leads, a transducer ceramic vibrator, a transducer heat insulation column, a temperature measuring platinum resistance thermometer, a transducer encapsulation sleeve, and platinum resistance thermometer leads. The length of the ultrasonic transducer is greater than the wall thickness of the constant temperature chamber lid. The transducer ceramic vibrator is a thin-walled circular ceramic device that generates and receives ultrasonic waves. The transducer heat insulation column is a round rod made of a fire-resistant and poorly thermally conductive non-metallic material. One end is fixedly connected to the transducer ceramic vibrator, and the other end passes through the constant temperature chamber lid, with its end face flush with the inner wall of the lid. Several temperature measuring platinum resistance thermometers are fixed along the axis of the transducer heat insulation column. The transducer encapsulation sleeve encapsulates and wraps the transducer ceramic vibrator and a small section of the transducer heat insulation column, and is located outside the constant temperature chamber lid. The material of the transducer heat insulation column and the temperature distribution of the transducer heat insulation column measured by the several temperature measuring platinum resistance thermometers can determine the sound velocity of the transducer heat insulation column.

[0022] The ultrasonic transducer in the ultrasonic thermometer or thermal balance detector obtains the thermal equilibrium temperature inside the constant temperature chamber as follows: The ultrasonic transducer emits an ultrasonic vibration signal at a given time. This vibration signal is transmitted as a sound wave to the reflecting surface of the constant temperature chamber, and then reflected by the reflecting surface. The ultrasonic transducer receives the ultrasonic signal reflected by the reflecting surface at a given time. Based on the known length between the inner wall of the lid and the reflecting surface, the length of the transducer's insulation column, the sound velocity of the transducer's insulation column, the adiabatic index of the ideal gas inside the constant temperature chamber, and the gas constant, a correlation can be derived according to the principle of ultrasonic wave propagation and the sound velocity of the ideal gas inside the constant temperature chamber. This correlation then yields the thermal equilibrium temperature inside the constant temperature chamber.

[0023] The measurement and control computer is connected to the ultrasonic thermometer via its ultrasonic transducer monitoring circuit. This allows the ultrasonic transducer in the ultrasonic thermometer to emit and receive ultrasonic waves, and to acquire the temperature of the platinum resistance thermometer in the transducer's insulation column. The measurement and control computer is also connected to the constant temperature chamber pressure gauge, the refrigeration chamber thermometer, and the refrigeration chamber pressure gauge to monitor their measured temperatures or pressures. Furthermore, the measurement and control computer is connected to the constant temperature chamber exhaust valve, the gas tank inlet valve, the gas tank outlet valve, the blower, the refrigeration chamber inlet valve, the heat balancer, the refrigeration unit, the refrigeration chamber outlet valve, and the constant temperature chamber inlet valve to perform measurement and control on these components.

[0024] The measurement and control computer performs the following operations to complete the calibration of the temperature sensor under test: A set temperature is created in the constant temperature chamber. By adjusting the gas supply unit, thermal balancer, and temperature-controlled heater, and monitoring by the thermal balance detector, it is determined that the ideal gas in the constant temperature chamber has reached thermal equilibrium at the set temperature. Then, the temperature of the ideal gas in the constant temperature chamber at this thermal equilibrium is measured by an ultrasonic thermometer and used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test and comparing it with this calibration standard temperature, the measurement error between the measured temperature of the temperature sensor under test and the calibration standard temperature is determined, thus completing the calibration of the temperature sensor under test at one calibration standard temperature. The above steps are repeated multiple times, creating a series of set temperatures in the constant temperature chamber and using these set temperatures as the calibration standard temperatures for each level of the temperature sensor under test. Simultaneously, the temperature measured by the temperature sensor under test at each calibration standard temperature is collected, thereby obtaining the measurement error, correction data, and correction curve of the temperature sensor under test at each calibration standard temperature.

[0025] Compared with the prior art, the present invention has outstanding substantive features and significant progress, which are manifested in:

[0026] First, this invention adopts a new principle of thermal balance temperature measurement, an innovative temperature sensor calibration method, and an innovative structure for calibrating temperature sensors. This enables the invention to achieve seven technical expectations for temperature sensor calibration devices: a wide calibrable temperature range, from -200℃ to 1800℃; high calibrable temperature accuracy, with a measurable temperature accuracy of over 99.99% or a measurement error of less than ℃; a large number of calibrable standard temperature points, up to 500; rapid and stable formation of calibrable standard temperature points; the ability to calibrate multiple temperature sensors; the ability to calibrate multiple temperature sensors simultaneously; and a procedural and easy-to-operate calibration process.

[0027] Secondly, this invention proposes a new approach and device for establishing calibration standard temperatures for temperature sensor calibration. Specifically, a gas supply unit is used to supply ideal gases at room temperature or different low temperatures to the constant temperature chamber for calibrating the temperature sensor. The gas then works in conjunction with the temperature control heater and thermal balancer in the constant temperature chamber to create a series of calibration standard temperatures for the temperature sensor under test.

[0028] Third, this invention proposes a new method and apparatus for obtaining the calibration standard temperature. Specifically, an ultrasonic transducer emits an ultrasonic vibration signal at a certain time, and receives an ultrasonic signal reflected by the reflective surface of the constant temperature chamber at a certain time. Based on the known structural parameters of the constant temperature chamber and the characteristic parameters of the ideal gas inside the constant temperature chamber, and according to the principle of ultrasonic wave propagation, this invention derives a correlation formula, from which the calibration standard temperature is obtained.

[0029] Fourth, this invention provides an innovative method and structure, namely, a novel ultrasonic transducer structure that is resistant to both low and high temperatures and can accurately determine the calibration standard temperature: the length of the ultrasonic transducer is greater than the wall thickness of the constant temperature chamber lid; the transducer insulation column is a round rod made of a fire-resistant and poorly thermally conductive non-metallic material, one end of which is fixedly connected to the transducer ceramic vibrator, and the other end passes through the constant temperature chamber lid, with its end face flush with the inner wall of the lid; several temperature-measuring platinum resistance thermometers are fixed along the axis of the transducer insulation column; the transducer encapsulation sleeve encapsulates and wraps the transducer ceramic vibrator and a short section of the transducer insulation column, and is located outside the constant temperature chamber lid; to prevent the operating temperature of the transducer ceramic vibrator in the ultrasonic transducer from exceeding its tolerance temperature, the ultrasonic transducer is equipped with a cooling water jacket, through which room temperature water flows in and out, cooling or heating the ultrasonic transducer to ensure that the ultrasonic transducer operates within its tolerance temperature range.

[0030] Fifth, this invention provides a new method and a thermal balance detector for determining whether an ideal gas in a constant temperature chamber has reached thermal equilibrium. The thermal balance detector consists of several ultrasonic transducers arranged in a ring, with another ultrasonic transducer located in the central region of the ring. The sound waves emitted directly from the ring-distributed ultrasonic transducers onto the reflective surface inside the constant temperature chamber will surround the probes of all the temperature sensors under test within the constant temperature chamber without being blocked by the temperature sensors under test.

[0031] Sixth, this invention provides a programmed operation for calibrating the temperature sensor under test: To achieve a set temperature in the constant temperature chamber, the gas supply unit, thermal balancer, and temperature-controlled heater are adjusted. Monitoring by the thermal balance detector reveals that the ideal gas in the constant temperature chamber has reached thermal equilibrium at the set temperature. Then, monitoring by the ultrasonic thermometer reveals the ideal gas temperature at this thermal equilibrium, which is used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test and comparing it with this calibration standard temperature, the measurement error between the measured temperature and the calibration standard temperature is determined. This process is repeated multiple times, involving a series of adjustments to the ideal gas set temperature in the constant temperature chamber and monitoring by the ultrasonic thermometer, resulting in a series of ideal gas set temperatures. These set temperatures are used as the calibration standard temperatures for each level of the temperature sensor under test. Simultaneously, the temperature measured by the temperature sensor under test at each calibration standard temperature is collected, thereby obtaining the measurement error, correction data, and correction curve of the temperature sensor under test at each calibration standard temperature. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a temperature sensor calibration device for ultrasonic temperature measurement.

[0033] Figure 2 This is a schematic diagram of the ultrasonic transducer structure.

[0034] Figure 3 This is a schematic diagram of the ring-shaped distribution structure of the ultrasonic transducer in the thermal balance detector.

[0035] In the picture:

[0036] 1. Bucket lid; 2. Bucket side wall top; 3. Temperature sensor socket; 4. Constant temperature chamber; 5. Temperature-controlled heater; 6. Reflective surface; 7. Bucket bottom; 8. Constant temperature chamber pressure gauge; 9. Constant temperature chamber exhaust valve; 10. Gas tank inlet pipe; 11. Gas tank inlet valve; 12. Gas tank; 13. Gas tank outlet valve; 14. Blower; 15. Gas tank outlet pipe; 16. Refrigeration chamber inlet valve; 17. Refrigeration chamber thermometer; 18. Refrigeration chamber pressure gauge; 19. Thermal balancer; 20. 21. Refrigeration unit evaporator; 22. Refrigeration chamber; 23. Refrigeration chamber exhaust valve; 24. Airflow shower head; 25. Refrigeration chamber exhaust pipe; 26. Constant temperature chamber inlet valve; 27. Tank side wall bottom; 28. Measurement and control computer; 29. ​​Thermal balance detector; 30. Ultrasonic thermometer; 31. Transducer lead wire; 32. Transducer ceramic vibrator; 33. Ultrasonic transducer; 34. Transducer heat insulation column; 35. Temperature measuring platinum resistance thermometer; 36. Transducer encapsulation sleeve; 37. Platinum resistance thermometer lead wire. Detailed Implementation

[0037] Example 1

[0038] The implementation of the present invention will now be described in further detail with reference to the accompanying drawings.

[0039] This embodiment is an ultrasonic temperature sensor calibration device that can calibrate 30 platinum resistance temperature sensors, 20 thermocouple temperature sensors, and 10 ultrasonic temperature sensors at the same time. All the temperature sensors to be tested are inserted into the test interface 3 on the constant temperature chamber 4 and the test interface 3 is sealed to prevent air leakage and provide heat insulation. The ideal gas used in this calibration device is nitrogen, and the temperature range for calibrating the temperature sensors is -150℃ to 1600℃.

[0040] This embodiment consists of a constant temperature chamber 4, a test instrument interface 3, a gas supply unit, a heat balancer 19, a temperature-controlled heater 5, a heat balance detector 29, an ultrasonic thermometer 30, and a measurement and control computer 28. (See attached diagram) Figure 1The constant temperature chamber 4 is a rigid container that contains ideal gas, calibrates the temperature sensor under test, and is strictly insulated from the outside. The interface 3 for the sensor under test is located on the wall of the constant temperature chamber and allows the probe of the temperature sensor under test to be inserted into the constant temperature chamber 4 from the outside. The gas supply unit is a combined device with the constant temperature chamber that has airflow inlet and outlet interfaces. The gas supply unit can supply ideal gas at room temperature or different low temperatures to the constant temperature chamber 4. It works in conjunction with the temperature-controlled heater 5 and the heat balancer 19 to create various calibration standard temperatures for the ideal gas in the constant temperature chamber 4. The heat balancer 19 is a driving device that drives the ideal gas in the constant temperature chamber to quickly reach thermal equilibrium. The temperature-controlled heater 5 is a device that controls the temperature of the ideal gas in the constant temperature chamber. The heat balance detector 29 is a detection device that detects whether the ideal gas in the constant temperature chamber 4 is in thermal equilibrium. The ultrasonic thermometer 30 detects the constant temperature based on the ultrasonic principle. The indoor ideal gas temperature detection equipment, when the heat balance detector 29 determines that the ideal gas in the constant temperature chamber 4 has reached thermal equilibrium, activates the ultrasonic thermometer 30 to measure the temperature of the ideal gas in the constant temperature chamber, and uses this temperature as the calibration standard temperature for calibrating the temperature sensor under test; the measurement and control computer 28 is an industrial control computer with an ultrasonic transducer monitoring circuit and the ability to perform data monitoring and control. The measurement and control computer performs the following calibration operation: by adjusting the gas supply unit, heat balancer 19, and temperature control heater 5 to a certain set temperature, the heat balance detector 29 determines that the ideal gas in the constant temperature chamber 4 has reached thermal equilibrium, the ultrasonic thermometer 30 measures the temperature of the ideal gas in the constant temperature chamber 4 under this thermal equilibrium, and uses this temperature as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test under this thermal equilibrium and comparing it with the calibration standard temperature, the measurement error between the temperature sensor under test and the calibration standard temperature is obtained.

[0041] In this embodiment, the constant temperature chamber 4 is a cylindrical rigid container with a lid 1 and a bottom 7. The walls of the constant temperature chamber 4 have three layers: an inner layer of fire-resistant ceramic with poor thermal conductivity, a middle layer of vacuum insulation, and an outer layer of stainless steel. A thermal balance detector 29 and an ultrasonic transducer 30 are installed on the upper part of the outer wall of the lid 1. The upper part of the inner wall of the bottom 7 is a polished surface, which serves as the reflective surface 6 for the ultrasonic transducer 33. Several test instrument sockets 3 are installed on the top 2 of the side wall of the constant temperature chamber 4 to house the temperature sensors to be tested. A thermal balancer 19 and a temperature control heater 5 are installed on the bottom 27 of the side wall of the constant temperature chamber 4. A constant temperature chamber pressure gauge 8 is installed inside the constant temperature chamber 4 to monitor the pressure of the ideal gas inside the constant temperature chamber 4.

[0042] In this embodiment, the gas supply unit, along the gas flow direction, sequentially connects the gas tank inlet pipe 10, the gas tank 12, the gas tank outlet pipe 15, the cooling chamber 22, the cooling chamber exhaust pipe 25, and the airflow shower 24. The gas tank inlet pipe 10 is equipped with a constant temperature chamber exhaust valve 9 and a gas tank inlet valve 11. The gas tank outlet pipe 15 is equipped with a gas tank outlet valve 13, a blower 14, and a cooling chamber inlet valve 16. The cooling chamber exhaust pipe 25 is equipped with a cooling chamber exhaust valve 23 and a constant temperature chamber inlet valve 26. The inlet end of the gas tank inlet pipe 10 is connected to the constant temperature chamber 4. The airflow shower 24 is located inside the constant temperature chamber 4 and sprays airflow into the constant temperature chamber 4 in a multi-hole dispersed manner. Inside the cooling chamber 22… The refrigeration unit 20 cools the ideal gas in the refrigeration chamber 22 through its evaporator 21. The refrigeration chamber 22 is equipped with a refrigeration chamber thermometer 17 and a refrigeration chamber pressure gauge 18 to monitor the temperature and pressure of the ideal gas in the refrigeration chamber 22. The refrigeration chamber exhaust valve 23 and the constant temperature chamber exhaust valve 9 are both electric regulating valves that can adjust the airflow of the refrigeration chamber exhaust pipe 25 and the gas storage tank inlet pipe 10. The gas storage tank inlet valve 11, the gas storage tank outlet valve 13, the refrigeration chamber inlet valve 16, and the constant temperature chamber inlet valve 26 are all electric shut-off valves that open or close. The blower 14 is a fluid drive device that pressurizes the ideal gas from the gas storage tank outlet pipe 15 and delivers it to the refrigeration chamber 22.

[0043] In this embodiment, the heat balancer 19 is an electric stirrer, and the part located in the constant temperature chamber 4, including the stirring blades, is made of refractory ceramic material with poor thermal conductivity; the temperature control heater 5 is an electric heater, made of refractory ceramic material with poor thermal conductivity.

[0044] In this embodiment, the ultrasonic thermometer 30 and the thermal balance detector 29 are the same device, differing only in their function; see Figure 3The ultrasonic thermometer 30 consists of seven ultrasonic transducers 33, six of which are arranged in a ring, with one transducer located in the center of the ring. The sound waves emitted directly from the ring-shaped ultrasonic transducers 33 onto the reflecting surface 6 inside the constant temperature chamber 4 will surround the probes of all temperature sensors under test within the constant temperature chamber 4 without being blocked by the temperature sensors themselves. The heat balance detector 29 will only determine the temperature difference between the seven ultrasonic transducers 33 in the heat balance detector 29 if it is less than the maximum allowable temperature error, such as 0.001℃. The ideal gas in the constant temperature chamber 4 has reached thermal equilibrium. At thermal equilibrium, the ultrasonic thermometer 30 takes the average temperature measured by the seven ultrasonic transducers 33 as the thermal equilibrium temperature or the calibration standard temperature. To prevent the operating temperature of the transducer ceramic oscillator 32 in the ultrasonic transducer 33 from exceeding its tolerance temperature (the tolerance temperature is generally -20℃ to 120℃), the ultrasonic thermometer 30 is equipped with a cooling water jacket. The cooling water jacket has room temperature water flowing in and out, and the ultrasonic transducer 33 is cooled or heated through the cooling water jacket to ensure that the ultrasonic transducer 33 operates within the tolerance temperature range.

[0045] The ultrasonic transducer 33 in this embodiment consists of transducer leads 31, transducer ceramic resonator 32, transducer heat insulation column 34, temperature measuring platinum resistance thermometer 35, transducer encapsulation sleeve 36, and platinum resistance thermometer leads 37. (See...) Figure 2 The length of the ultrasonic transducer 33 is greater than the wall thickness of the barrel lid 1 of the constant temperature chamber 4; the transducer ceramic vibrator 32 is a thin-walled circular device that generates and receives ultrasonic waves; the transducer heat insulation column 34 is a cylindrical rod made of refractory ceramic material with poor thermal conductivity, one end of which is fixedly connected to the transducer ceramic vibrator 32, and the other end passes through the barrel lid 1 of the constant temperature chamber 4 and makes its end face flush with the inner wall surface of the barrel lid 1. Four temperature measuring platinum resistance thermometers 35 are fixed along the axial direction of the transducer heat insulation column 33; the transducer encapsulation sleeve 36 encapsulates and wraps the transducer ceramic vibrator 32 and one-sixth of the transducer heat insulation column 34, and is located outside the barrel lid 1 of the constant temperature chamber 4; the temperature distribution of the transducer heat insulation column 34 measured by the ceramic material made of the transducer heat insulation column 34 and the four temperature measuring platinum resistance thermometers 35 can determine the sound velocity of the transducer heat insulation column 34.

[0046] In this embodiment, the ultrasonic transducer 33 in the ultrasonic thermometer 30 or thermal balance detector 29 obtains the thermal balance temperature inside the constant temperature chamber 4 as follows: The ultrasonic transducer 33 emits an ultrasonic vibration signal at a given time. This vibration signal is transmitted to the reflecting surface 6 of the constant temperature chamber 4 in the form of a sound wave, and then reflected by the reflecting surface 6. The ultrasonic transducer 33 receives the ultrasonic signal reflected by the reflecting surface 6 at a given time. Based on the known length between the inner wall of the lid 1 and the reflecting surface 6, the length of the transducer insulation column 34, the sound velocity of the transducer insulation column 34, the adiabatic index and gas constant of the ideal gas inside the constant temperature chamber, and according to the principle of ultrasonic propagation and the sound velocity of the ideal gas inside the constant temperature chamber, a correlation can be obtained. From this correlation, the thermal balance temperature inside the constant temperature chamber 4 is derived.

[0047] In this embodiment, the measurement and control computer 28 is connected to the ultrasonic thermometer 30 via its ultrasonic transducer monitoring circuit. This allows the ultrasonic transducer 35 in the ultrasonic thermometer 30 to emit and receive ultrasonic waves, and to acquire the temperature of the temperature measuring platinum resistance thermometer 35 in the transducer insulation column 34. The measurement and control computer 28 is also connected to the constant temperature chamber pressure gauge 8, the refrigeration chamber thermometer 17, and the refrigeration chamber pressure gauge 18 to obtain the measured temperature or pressure. Furthermore, the measurement and control computer 28 is connected to the constant temperature chamber exhaust valve 9, the gas tank inlet valve 11, the gas tank outlet valve 13, the blower 14, the refrigeration chamber inlet valve 16, the thermal balancer 19, the refrigerator 20, the refrigeration chamber outlet valve 23, and the constant temperature chamber inlet valve 26 to perform measurement and control on these components.

[0048] In this embodiment, the measurement and control computer 28 performs the following operations to complete the calibration of the temperature sensor under test: A set temperature is created in the constant temperature chamber 4. By adjusting the gas supply unit, the thermal balancer 19, and the temperature-controlled heater 5, and monitoring by the thermal balance detector 29, it is determined that the ideal gas in the constant temperature chamber 4 has reached thermal equilibrium at the set temperature. Then, the temperature of the ideal gas in the constant temperature chamber 4 at this thermal equilibrium is measured by the ultrasonic thermometer 30 and used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test and comparing it with this calibration standard temperature, the measurement error between the temperature measured by the temperature sensor under test and the calibration standard temperature is determined, thus completing the calibration of the temperature sensor under test at one calibration standard temperature. The above steps are repeated multiple times, that is, a series of set temperatures are created in the constant temperature chamber 4, and these series of set temperatures are used as the calibration standard temperatures for each level of the temperature sensor under test. Simultaneously, the temperature measured by the temperature sensor under test at each calibration standard temperature is collected, thereby obtaining the measurement error, correction data, and correction curve of the temperature sensor under test at each calibration standard temperature.

[0049] This embodiment operates as follows:

[0050] Before the temperature sensor calibration begins, the gas supply unit closes all valves 9, 11, 13, 16, 23, and 26, and stops blower 14 and refrigeration unit 20. The gas storage tank 12 contains nitrogen for calibration. The gas supply unit provides air to the constant temperature chamber 4 in two ways: a normal temperature intake program and a low temperature intake program. The normal temperature intake program involves opening valves 13, 16, 23, and 26 and starting blower 14. Blower 14 draws ideal gas from the gas storage tank 12, pressurizes it, and delivers it to the constant temperature chamber 4 via the gas storage tank outlet pipe 15, the refrigeration chamber 22, and the refrigeration chamber exhaust pipe 25. When the pressure measured by the constant temperature chamber pressure gauge 8 reaches the limit pressure, such as 0.2 MPa, valves 13, 16, 23, and 26 are closed, and blower 14 is turned off, ending the normal temperature intake program. The low temperature intake program involves opening valves 13 and 16 and starting blower 14. Blower 14 draws ideal gas from the gas storage tank 12... The gas is pressurized and delivered to the refrigeration chamber 22 via the gas tank outlet pipe 15. When the pressure measured by the refrigeration chamber pressure gauge 18 reaches the limit pressure, such as 0.25 MPa, valves 13 and 16 are closed and the blower 14 is turned off. Then, the refrigeration unit 20 is turned on. When the temperature measured by the refrigeration chamber thermometer 17 reaches the temperature required for verification, the refrigeration unit 20 is turned off and valves 23 and 26 are opened. Relying on the pressure of the gas itself in the refrigeration chamber 22, the low-temperature ideal gas in the refrigeration chamber 22 enters the constant temperature chamber 4 through the refrigeration chamber exhaust pipe 25. This process continues until the temperature of the ideal gas in the constant temperature chamber 4 reaches the low temperature required for verification. Then, valves 23 and 26 are closed, and the low-temperature gas intake process ends.

[0051] The temperature sensor under test is now being calibrated from room temperature (20°C) to 1600°C, with each 10°C increase from 20°C serving as a calibration standard temperature. The control computer 28 initiates a room temperature intake program to create a set temperature of 20°C for the constant temperature chamber 4. Through adjustments to the gas supply unit, thermal balancer 19, and temperature-controlled heater 5, and monitoring by the thermal balance detector 29, it is determined that the ideal gas within the constant temperature chamber 4 has reached thermal equilibrium at the set temperature. Then, the ultrasonic thermometer 30 measures the temperature of the ideal gas within the constant temperature chamber 4 at this thermal equilibrium, which is used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test and comparing it with this calibration standard temperature, the measurement error between the temperature measured by the temperature sensor under test and the calibration standard temperature is determined, thus completing the calibration process. The temperature sensor is calibrated at a standard temperature of 20℃. Then, through adjustments to the thermal balancer 19 and the temperature-controlled heater 5, it enters a calibration process with multiple standard temperatures, such as the second, third, and fourth. Specifically, a series of set temperatures are created in the constant temperature chamber 4, ranging from 30℃ to 1600℃, with each 10℃ increment serving as a standard temperature. These set temperatures are used as the various standard temperatures for the temperature sensor under test. Simultaneously, the temperature measured by the sensor at each standard temperature is collected, thus deriving the measurement error, correction data, and correction curve of the sensor under test at each standard temperature. During the calibration process, heating the ideal gas inside the constant temperature chamber 4 will increase the gas pressure. If the pressure measured by the pressure gauge 8 in the constant temperature chamber is too high, such as exceeding 2MPa, the control computer 28 will activate the exhaust valve 9 of the constant temperature chamber and the inlet valve 11 of the gas storage tank to depressurize the constant temperature chamber 4 until the pressure measured by the pressure gauge 8 is below 2MPa. Then, the exhaust valve 9 and the inlet valve 11 are closed.

[0052] The temperature sensor under test is now being calibrated from 15℃ to -150℃, with each 5℃ decrease from 15℃ serving as a calibration standard temperature. The control computer 28 initiates a low-temperature air intake program to create a set temperature of 15℃ for the constant temperature chamber 4. Through adjustments to the air supply unit and the thermal balancer 19, including fine-tuning of the temperature-controlled heater 5, and monitoring by the thermal balance detector 29, it is determined that the ideal gas within the constant temperature chamber 4 has reached thermal equilibrium at the set temperature. Then, the ultrasonic thermometer 30 measures the temperature of the ideal gas within the constant temperature chamber 4 at this thermal equilibrium, which is used as the calibration standard temperature. By collecting the temperature measured by the temperature sensor under test and comparing it with this calibration standard temperature, the measurement error between the measured temperature of the temperature sensor under test and the calibration standard temperature is determined, thus completing the calibration of the temperature sensor under test at 15℃. The standard temperature is then set for calibration. Then, the measurement and control computer 28 continues to start the low-temperature air intake program. By adjusting the air supply unit and the heat balancer 19, as well as fine-tuning the temperature control heater 5, it enters the calibration process of multiple calibration standard temperatures, such as the second, third, fourth, etc. That is, a series of set temperatures are created in the constant temperature room 4, from 10℃ to -150℃, with each 5℃ decrease serving as a calibration standard temperature. This series of set temperatures is used as the calibration standard temperatures of the temperature sensor under test at each level. At the same time, the temperature measured by the temperature sensor under test at each level of calibration standard temperature is collected. Thus, the measurement error, correction data, and correction curve of the temperature sensor under test at each level of calibration standard temperature are obtained.

Claims

1. A temperature sensor calibration device of ultrasonic temperature measurement type, characterized in that: The utility model relates to a kind of temperature sensor calibration device, including constant-temperature chamber (4), table interface (3) to be detected, gas supply unit, temperature control heater (5), thermal equilibrium device (19), thermal equilibrium detector (29), ultrasonic temperature detector (30), ultrasonic transducer (33), measurement and control computer (28), wherein the constant-temperature chamber (4) is rigid container for accommodating ideal gas, calibrating temperature sensor to be detected, and strictly adiabatic with outside;The table interface (3) to be detected is located on constant-temperature chamber wall, and the probe of temperature sensor to be detected can be inserted into constant-temperature chamber (4) from outside into table interface (3) to be detected;The gas supply unit is combined equipment with the gas flow interface of constant-temperature chamber (4) in and out, and the gas supply unit transports ideal gas of normal temperature or different low temperature to constant-temperature chamber (4), cooperates with temperature control heater (5) and thermal equilibrium device (19) and is used as ideal gas in constant-temperature chamber (4) to create various levels of calibration standard temperature;The thermal equilibrium device (19) is the driving device for driving ideal gas in constant-temperature chamber (4) to reach thermal equilibrium quickly;The temperature control heater (5) is the device for temperature control heating ideal gas in constant-temperature chamber;The thermal equilibrium detector (29) is the detection device for detecting whether ideal gas in constant-temperature chamber (4) is in thermal equilibrium;The ultrasonic temperature detector (30) and thermal equilibrium detector (29) are the same device, and the difference is only that the roles and purposes are different, and it is composed of several ultrasonic transducers (33), and it is the detection device for detecting the temperature of ideal gas in constant-temperature chamber according to ultrasonic principle, when thermal equilibrium detector (29) determines that ideal gas in constant-temperature chamber (4) reaches thermal equilibrium, ultrasonic temperature detector (30) is started to measure the temperature of ideal gas in constant-temperature chamber (4), and serves as the calibration standard temperature for calibrating temperature sensor to be detected;The ultrasonic transducer (33) includes transducer lead (31), transducer ceramic vibrator (32), transducer heat insulation column (34), temperature measuring platinum resistance (35), transducer packaging sleeve (36) and platinum resistance lead (37), and the length of ultrasonic transducer (33) is greater than the wall thickness of barrel cover (1) of constant-temperature chamber (4);The transducer ceramic vibrator (32) is circular thin-wall ceramic device for generating and receiving ultrasonic wave;The transducer heat insulation column (34) is cylindrical rod made of non-metallic material with poor thermal conductivity, one end is fixedly connected with transducer ceramic vibrator (32), the other end passes through the barrel cover (1) of constant-temperature chamber (4) and makes its end face flush with the inner wall surface of barrel cover (1), and several temperature measuring platinum resistances (35) are fixed along the axial direction of transducer heat insulation column (34);The transducer packaging sleeve (36) encapsulates and wraps transducer ceramic vibrator (32) and a little transducer heat insulation column (34), and is located outside the barrel cover (1) of constant-temperature chamber (4);The speed of sound of transducer heat insulation column (34) is determined by the material of transducer heat insulation column (34) and the temperature distribution of several temperature measuring platinum resistances (35) measured on transducer heat insulation column (34).The ultrasonic transducer (33) in the ultrasonic temperature detector (30) obtains the thermal equilibrium temperature in the constant temperature chamber (4) by the following steps: the ultrasonic transducer (33) sends an ultrasonic vibration signal at time 0, the vibration signal is transmitted to the reflecting surface (6) of the constant temperature chamber (4) in the form of sound wave, then is reflected by the reflecting surface (6), the ultrasonic transducer (33) receives the ultrasonic signal reflected by the reflecting surface (6) at time 1, according to the known length between the inner wall of the bucket cover (1) and the reflecting surface (6), the length of the transducer heat insulation column (34), the sound speed of the transducer heat insulation column (34), the adiabatic index and the gas constant of the ideal gas in the constant temperature chamber, and the sound speed of the ideal gas in the constant temperature chamber, the correlation formula is obtained according to the ultrasonic propagation principle, and thus the thermal equilibrium temperature in the constant temperature chamber (4) is obtained; the measurement and control computer (28) is an industrial computer with an ultrasonic transducer monitoring circuit and data monitoring function, and the measurement and control computer performs the following calibration operation: the temperature of the ideal gas in the constant temperature chamber (4) reaches thermal equilibrium by adjusting the temperature of the gas supply unit, the thermal equilibrium detector (29) and the temperature control heater (5) to a certain set temperature, the temperature of the ideal gas in the constant temperature chamber (4) at the thermal equilibrium is measured by the ultrasonic temperature detector (30), and the temperature is taken as the calibration standard temperature, the measurement error of the temperature measured by the temperature sensor to be detected and the calibration standard temperature is obtained by comparing the temperature measured by the temperature sensor to be detected with the calibration standard temperature at the thermal equilibrium.

2. The ultrasonic temperature sensor calibrating device according to claim 1, wherein: The constant temperature chamber (4) is a cylindrical rigid container with a barrel cover (1) and a barrel bottom (7) and horizontally placed. The wall of the constant temperature chamber (4) has a three-layer structure, the inner layer is a non-metallic layer with fire resistance and poor thermal conductivity, the middle layer is a vacuum insulation layer, and the outer layer is a metal material layer. A thermal equilibrium detector (29) and an ultrasonic temperature detector (30) are installed in the upper part of the outer wall of the barrel cover (1). The inner wall surface of the barrel bottom (7) is polished as a reflection surface (6) for the ultrasonic transducer (33). A plurality of table insertion ports (3) are installed on the top (2) of the barrel side wall of the constant temperature chamber (4) to accommodate the temperature sensor to be detected. A thermal equilibrium device (19) and a temperature control heater (5) are installed on the bottom (27) of the barrel side wall of the constant temperature chamber (4). A constant temperature chamber pressure gauge (8) is installed in the constant temperature chamber (4) to monitor the pressure of the ideal gas in the constant temperature chamber (4).

3. The ultrasonic temperature sensor calibrating device according to claim 1, wherein: The gas supply unit sequentially connects the gas tank inlet pipe (10), the gas tank (12), the gas tank outlet pipe (15), the refrigeration chamber (22), the refrigeration chamber exhaust pipe (25) and the air flow shower (24) along the gas flow direction. The gas tank inlet pipe (10) is provided with a constant temperature chamber exhaust valve (9) and a gas tank inlet valve (11). The gas tank outlet pipe (15) is provided with a gas tank outlet valve (13), a blower (14) and a refrigeration chamber inlet valve (16). The refrigeration chamber exhaust pipe (25) is provided with a refrigeration chamber exhaust valve (23) and a constant temperature chamber inlet valve (26). The inlet end of the gas tank inlet pipe (10) is communicated with the constant temperature chamber (4). The air flow shower (24) is located in the constant temperature chamber (4) and sprays the gas flow into the constant temperature chamber (4) in a porous and dispersed manner. In the refrigeration chamber (22), the refrigeration machine (20) cools and refrigerates the ideal gas in the refrigeration chamber (22) through the refrigeration machine evaporator (21) thereon. The refrigeration chamber (22) is provided with a refrigeration chamber thermometer (17) and a refrigeration chamber pressure gauge (18) to monitor the temperature and pressure of the ideal gas in the refrigeration chamber (22). The refrigeration chamber exhaust valve (23) and the constant temperature chamber exhaust valve (9) are both electrically adjustable valves for adjusting the air flow of the refrigeration chamber exhaust pipe (25) and the gas tank inlet pipe (10). The gas tank inlet valve (11), the gas tank outlet valve (13), the refrigeration chamber inlet valve (16) and the constant temperature chamber inlet valve (26) are all electrically controlled on-off valves. The blower (14) is a fluid driving device for pressurizing and delivering the ideal gas from the gas tank outlet pipe (15) into the refrigeration chamber (22).

4. The ultrasonic temperature sensor calibrating device according to claim 1, wherein: The thermal equilibrium device (19) is an electric stirrer, and the part located in the constant temperature chamber (4) includes a stirring paddle, which is made of non-metallic material with fire resistance and poor thermal conductivity. The temperature control heater (5) is an electric heater made of non-metallic material with fire resistance and poor thermal conductivity.

5. The ultrasonic temperature sensor calibrating device according to claim 1, wherein: The heat balance detector (29) comprises several ultrasonic transducers (33), wherein the sound wave lines emitted by the several ultrasonic transducers (33) to the reflecting surface (6) in the thermostat chamber (4) are directed to the probes of all the temperature sensors to be detected in the thermostat chamber (4) and are not blocked by the temperature sensors to be detected; only when the temperature difference between the temperatures measured by the several ultrasonic transducers (33) in the heat balance detector (29) is less than the maximum allowable temperature difference, the heat balance detector (29) determines that the ideal gas in the thermostat chamber (4) has reached thermal equilibrium; at the time of thermal equilibrium, the ultrasonic temperature detector (30) takes the average value of the temperatures measured by the several ultrasonic transducers (33) as the heat balance temperature, i.e. the standard temperature for detection; in order to prevent the operating temperature of the transducer ceramic vibrator (32) in the ultrasonic transducer (33) from exceeding its tolerance temperature, the ultrasonic temperature detector (30) is equipped with a cooling water jacket, which has normal temperature water flowing in and out, and the ultrasonic transducer (33) is cooled or heated by the cooling water jacket to ensure that the ultrasonic transducer (33) operates within the tolerance temperature range.

6. The ultrasonic temperature sensor calibrating device according to claim 1, wherein: The measurement and control computer (28) is connected with the ultrasonic temperature detector (30) through the ultrasonic transducer monitoring circuit thereon, for making the ultrasonic transducer (33) in the ultrasonic temperature detector (30) emit and receive ultrasonic waves, and obtaining the temperature of the temperature measuring platinum resistance (35) in the transducer heat insulation column (34); the measurement and control computer (28) is connected with the thermostat chamber pressure gauge (8), the refrigeration chamber thermometer (17) and the refrigeration chamber pressure gauge (18) to obtain the temperature or pressure measured thereby; the measurement and control computer (28) is connected with the thermostat chamber exhaust valve (9), the gas tank inlet valve (11), the gas tank outlet valve (13), the air blower (14), the refrigeration chamber inlet valve (16), the heat balance device (19), the refrigeration machine (20), the refrigeration chamber outlet valve (23) and the thermostat chamber inlet valve (26) to implement measurement and control thereon.

7. The ultrasonic temperature sensor calibrating device according to claim 1, wherein: The measurement and control computer (28) implements the following operation to complete the calibration of the temperature sensor to be tested: a certain set temperature is created in the thermostat room (4), through the adjustment of the air supply unit, the heat balance device (19) and the temperature control heater (5), the ideal gas in the thermostat room (4) reaches the heat balance at the set temperature through the monitoring of the heat balance detector (29), and the temperature of the ideal gas in the thermostat room (4) at the heat balance is measured by the ultrasonic temperature detector (30) as the calibration standard temperature. Through the comparison of the measured temperature of the temperature sensor to be tested and the calibration standard temperature, the measurement error between the measured temperature of the temperature sensor to be tested and the calibration standard temperature is obtained, thereby completing the calibration of the temperature sensor to be tested at one calibration standard temperature. The above steps are repeated multiple times, that is, a series of set temperatures are created in the thermostat room (4), and the series of set temperatures are used as the respective calibration standard temperatures of the temperature sensor to be tested. The measured temperature of the temperature sensor to be tested at each calibration standard temperature is collected, and the measurement error, the correction data and the correction curve of the temperature sensor to be tested at each calibration standard temperature are obtained.

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