Radiation thermometer calibration device and method

Abstract

The invention provides a radiation thermometer calibration device and method. The radiation thermometer calibration device comprises a high-temperature black body source system, a rhenium-carbon eutectic crucible, a heat preservation grating structure and a displacement mechanism. The high-temperature blackbody source system comprises a temperature control system, a blackbody radiation source, a vacuum inflation system, a water cooling system and a data acquisition device. The temperature control system comprises a temperature control sensor and a heating device. The rhenium-carbon eutectic crucible is arranged in the center of an inner cavity of the blackbody radiation source, the two sides of the rhenium-carbon eutectic crucible are each provided with a heat preservation grating structure, the calibrated radiation thermometer is fixedly installed on the displacement mechanism, and the calibrated radiation thermometer and the temperature control sensor are arranged at inlets in the two sides of the inner cavity of the blackbody radiation source respectively. And the calibrated radiation thermometer is aligned with the aiming cavity of the rhenium-carbon eutectic crucible and is connected with the data acquisition equipment through a data line. The temperature rise curve is controlled to ensure that the eutectic point temperature plateau appears, the rhenium-carbon eutectic state is reproduced, it is ensured that fixed point absolute method calibration is achieved, and the possibility that the temperature plateau does not appear in the prior art is avoided.

Description

Technical Field

[0001] This invention relates to a radiation thermometer calibration device and method, belonging to the field of non-contact high-temperature metrology technology. Background Technology

[0002] In the fields of metallurgy, casting, chemical industry, manufacturing, and military industries such as aerospace, radiation thermometers such as photoelectric pyrometers and infrared thermometers are widely used to measure high temperatures on solid surfaces. For high-precision measurements or calibrations, absolute radiation thermometers are also used, but they are not commonly used due to their high price.

[0003] Currently, in the metrology system, working radiation thermometers are traced step by step through comparison and are routinely calibrated using standard photoelectric pyrometers. However, standard photoelectric pyrometers themselves have large measurement uncertainties, and the wavelength ranges of the radiation thermometer being calibrated and the standard photoelectric pyrometer are different, which may lead to measurement differences. Therefore, the uncertainty introduced during the calibration process is large. Moreover, the measurement uncertainty of standard photoelectric pyrometers at high temperatures above 2000 degrees Celsius is generally 6℃ to 8℃, which cannot meet the calibration requirements of radiation thermometers and absolute radiation thermometers with high accuracy requirements. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a radiation thermometer calibration method and device that can effectively improve calibration uncertainty without the need for a standard photoelectric pyrometer.

[0005] The technical solution of this invention: a radiation thermometer calibration device, comprising a high-temperature blackbody source system, a rhenium-carbon eutectic crucible, and a displacement mechanism. The high-temperature blackbody source system includes a temperature control system, a blackbody radiation source, a vacuum filling system, a water cooling system, and a data acquisition device. The temperature control system includes a temperature control sensor and a heating device. The rhenium-carbon eutectic crucible is located at the center of the inner cavity of the blackbody radiation source. A set of heat-insulating grating structures is set on each side of the rhenium-carbon eutectic crucible. The radiation thermometer to be calibrated is fixedly installed on the displacement mechanism. The radiation thermometer to be calibrated and the temperature control sensor are respectively set at the inlets on both sides of the inner cavity of the blackbody radiation source. The radiation thermometer to be calibrated is aligned with the aiming cavity of the rhenium-carbon eutectic crucible. The radiation thermometer to be calibrated is connected to the data acquisition device via a data cable.

[0006] The temperature control system has a preset temperature control curve. The system controls the heating device according to the temperature control curve to control the temperature of the blackbody radiation source during the calibration process. The temperature control curve is as follows: room temperature rises to temperature A, temperature rises from temperature A to temperature C and holds for a certain time, temperature rises from temperature C to temperature D and holds for a certain time, temperature drop from temperature D to temperature C and holds for a certain time, and temperature drop from temperature C to room temperature. Temperature A is 800℃~850℃, temperature C is 30℃~35℃ below the rhenium-carbide eutectic temperature, and temperature D is 25℃~30℃ above the rhenium-carbide eutectic temperature. Temperature C is held for at least 10 minutes, and temperature D is held for 10 minutes~15 minutes.

[0007] A method for calibrating a radiation thermometer, characterized by comprising the following steps:

[0008] The first step is to set up the temperature control curve.

[0009] The temperature control curve is as follows: temperature rises from room temperature to temperature A, temperature rises from temperature A to temperature C and holds for a certain time, temperature rises from temperature C to temperature D and holds for a certain time, temperature drops from temperature D to temperature C and holds for a certain time, and temperature drops from temperature C to room temperature. Temperature A is 800℃~850℃, temperature C is 30℃~35℃ below the rhenium-carb eutectic temperature, temperature D is 25℃~30℃ above the rhenium-carb eutectic temperature, temperature C is held for at least 10 minutes, and temperature D is held for 10 minutes~15 minutes.

[0010] The second step is the preparation steps before calibration.

[0011] The third step is the installation of the rhenium-carbon eutectic crucible and the heat-insulating grating structure.

[0012] A3.1 Place the rhenium-carbon eutectic crucible at the center of the inner tube of the blackbody radiation source;

[0013] A3.2 Place the grating assembly and the insulation ring on both sides of the rhenium-carbon eutectic crucible in sequence and direction. The insulation ring and the grating assembly are set alternately. The grating assembly is on the side closer to the rhenium-carbon eutectic crucible. The insulation grating structures on both sides of the rhenium-carbon eutectic crucible are set symmetrically.

[0014] The fourth step is cold focusing. Place the circular positioning plate on both sides of the furnace opening inside the blackbody radiation source tube so that the center standard point of the temperature control sensor and the radiation thermometer being calibrated coincides with the center point of the circular positioning plate.

[0015] Step 5: Cleaning the inner cavity of the blackbody radiation source tube;

[0016] Step 6: Thermal focusing.

[0017] A6.1. Following the temperature control curve set in step one, raise the blackbody radiation source from room temperature to temperature A;

[0018] A6.2 At temperature A, perform thermal focusing on the radiation thermometer to be calibrated so that the center standard point of the radiation thermometer to be calibrated is aligned with the center point of the field of view of the aiming cavity of the rhenium-carbon eutectic crucible through which the heat-insulating grating structure passes.

[0019] Step 7: Perform temperature control and data acquisition according to the temperature control curve set in Step 1;

[0020] Step 8: Data processing.

[0021] A8.1. Extract a portion of the data collected in step seven. The extracted data must include either a heating process to temperature D or a cooling process from temperature D.

[0022] A8.2 Perform function fitting on the data extracted in step A8.1 to obtain the time-output value function and time-output value curve of the acquisition time x and the output voltage y of the radiation thermometer under calibration;

[0023] A8.3. Take the second derivative of the time-output value function fitted in step A8.2 to obtain two inflection points;

[0024] A8.4. Using the two inflection points obtained in step A8.3 as the starting and ending points on the time-output value curve fitted in step A8.2, obtain the voltage difference between the two points.

[0025] A8.5. Compare the voltage difference obtained in step A8.4 or step A8.6 with the differential voltage value of the radiation thermometer being calibrated. If the voltage difference is less than or equal to the differential voltage value, proceed to step A8.7. If the voltage difference is greater than the differential voltage value, proceed to step A8.6.

[0026] A8.6 Narrow the time range between the start and end points, re-mark the start and end points on the time-output value curve, and obtain the voltage difference between the two points. Repeat steps A8.5 to A8.6 until the voltage difference is less than or equal to the differential voltage value.

[0027] A8.7 Obtain the time interval in which the voltage difference is less than or equal to the differential voltage value, calculate the average voltage value of the time interval, and obtain the temperature value corresponding to the radiation thermometer being calibrated based on the average voltage value. The difference between this temperature value and the rhenium-carbon eutectic point temperature is the temperature calibration error value of the radiation thermometer being calibrated.

[0028] The beneficial effects of this invention compared to the prior art are as follows:

[0029] (1) This invention ensures the appearance of the eutectic point temperature plateau by controlling the heating curve, thus reproducing the rhenium-carbon eutectic state and ensuring the realization of the fixed-point absolute method calibration, avoiding the possibility that the temperature plateau may not appear in the prior art;

[0030] (2) The present invention uses a dual focusing process of hot and cold to ensure that the radiation thermometer is highly aligned with the focus;

[0031] (3) The present invention employs a special heat-insulating grating structure to control the energy dissipation of radiation;

[0032] (4) This invention does not require the use of a standard radiation thermometer, but can still be calibrated and the measurement uncertainty can reach U = 1.6℃ (k = 2), which is significantly better than the existing high temperature radiation thermometer calibration using a standard photoelectric pyrometer as the main standard, and its calibration uncertainty is around U = 6℃ to 8℃ (k = 2).

[0033] (5) The calibration method of the present invention accurately determines the melting process and time by interpreting the eutectic reaction initiation point and melting point;

[0034] (6) The calibration method of the present invention is applicable to the high-accuracy calibration of various high-temperature radiation thermometers, such as absolute radiation thermometers, photoelectric pyrometers, infrared thermometers, etc. Attached Figure Description

[0035] Figure 1 This is a block diagram illustrating the system principle of the present invention;

[0036] Figure 2 This is a structural arrangement diagram of the crucible and heat-insulating grating of the present invention;

[0037] Figure 3 This is an example of the temperature control curve of the present invention;

[0038] Figure 4 This is a flowchart of the present invention;

[0039] Figure 5 This is a flowchart of the temperature plateau identification and calculation process of the present invention. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific examples and accompanying drawings.

[0041] This invention utilizes the physical phenomenon that the temperature remains constant during the rhenium-carbon eutectic process to calibrate a high-temperature radiation thermometer, and provides equipment and methods for calibrating the radiation thermometer at the rhenium-carbon eutectic point.

[0042] The present invention is as follows Figure 1 As shown, a radiation thermometer calibration device is provided, including a high-temperature blackbody source system, a rhenium-carbon eutectic crucible, a heat-insulating grating structure, and a displacement mechanism. The high-temperature blackbody source system includes a temperature control system, a blackbody radiation source, a vacuum filling system, a water cooling system, and a data acquisition device. The temperature control system includes a temperature sensor and a heating device. The rhenium-carbon eutectic crucible is located at the center of the blackbody radiation source's inner cavity. A set of heat-insulating grating structures is set on each side of the rhenium-carbon eutectic crucible. The radiation thermometer to be calibrated is fixedly mounted on the displacement mechanism. The radiation thermometer to be calibrated and the temperature sensor are respectively installed at the inlets on both sides of the blackbody radiation source's inner cavity. The radiation thermometer to be calibrated is aligned with the aiming cavity of the rhenium-carbon eutectic crucible. The radiation thermometer to be calibrated is connected to the data acquisition device via a data cable.

[0043] Furthermore, the temperature control system of this invention has a pre-set temperature control curve. The system controls the heating device according to this curve to control the temperature of the blackbody radiation source during the calibration process. The temperature control curve is as follows: temperature rises from room temperature to temperature A, temperature rises from temperature A to temperature C and holds for a certain time, temperature rises from temperature C to temperature D and holds for a certain time, temperature drop from temperature D to temperature C and holds for a certain time, and temperature drop from temperature C to room temperature. Temperature A is 800℃~850℃, temperature C is 30℃~35℃ below the rhenium-carbide eutectic temperature, and temperature D is 25℃~30℃ above the rhenium-carbide eutectic temperature. Temperature C is held for at least 10 minutes, and temperature D is held for 10 minutes~15 minutes. This invention, by setting a special temperature control curve, ensures the emergence of the rhenium-carbide eutectic temperature plateau and reduces the probability of cracking during repeated calibration.

[0044] Further preferably, during the process of raising the temperature from A to C, the temperature is first raised from A to B and held for a certain period of time before being raised from B to C, wherein temperature B is 15°C to 25°C lower than temperature C. More preferably, the temperature is raised from A to B at a rate of less than 20°C / min, and held at B for at least 1 hour to better ensure uniform system temperature, before being raised from B to C at a rate of less than 20°C / min.

[0045] Further optimization involves raising the temperature from C to D within 3–5 minutes.

[0046] Further preferred, the temperature is reduced from temperature D to temperature C at a rate of less than 20°C / min.

[0047] Further preferably, during the process of cooling from temperature C to room temperature, the temperature is first lowered from temperature C to temperature B and held for a certain period of time, then lowered from temperature B to temperature A, and then naturally cooled from temperature A to room temperature. More preferably, the temperature is lowered from temperature C to temperature B at a rate of less than 20°C / min, held at temperature B for at least 10 minutes, and then lowered from temperature B to temperature A at a rate of less than 20°C / min. Figure 3 As shown, an example of temperature control curve design is given.

[0048] This invention provides a high-temperature blackbody source system that offers a temperature and calibration environment. The specific structural design utilizes existing technology. The temperature control system includes a temperature sensor and a heating device. The temperature sensor monitors the blackbody radiation source temperature and provides feedback to the temperature control system to adjust the heating power of the heating device. A vacuum filling system is used to evacuate the blackbody radiation source and introduce an inert gas (typically argon) for cleaning the inner cavity of the blackbody radiation source and preventing oxidation of the eutectic crucible. A water cooling system is used to reduce the temperature of the outer wall of the blackbody radiation source, ensuring operator safety. A data acquisition device is used to collect the output of the calibrated radiation thermometer.

[0049] Furthermore, the heat-insulating grating structure of this invention is used to prevent heat leakage from the eutectic point crucible and to assist the temperature control sensor and the calibrated radiation thermometer in alignment and focusing. For example... Figure 2 As shown, the thermal insulation grating structure of the present invention consists of multiple thermal insulation rings and grating components arranged alternately. The grating component is located on the side closer to the rhenium-carbon eutectic crucible, and the thermal insulation grating structures on both sides of the rhenium-carbon eutectic crucible are arranged symmetrically.

[0050] More preferably, the grating assembly is a sheet-like circular ring structure with a centrally machined circular hole. The radius of the central hole of the grating assembly decreases as it approaches the rhenium-carbohydrate eutectic crucible. The radius of the central hole of the innermost grating assembly (closest to the rhenium-carbohydrate eutectic crucible) is larger than the radius of the aiming cavity of the rhenium-carbohydrate eutectic crucible, while the radius of the central hole of the outermost grating assembly is 1.5 to 2 times the radius of the aiming cavity of the rhenium-carbohydrate eutectic crucible. The radius of the central hole of the grating assembly increases from the inside to the outside. More preferably, the grating assembly is made of graphite material, which is more compact than the insulation ring and has a thin sheet structure, with a thickness sufficient to ensure the strength required for use.

[0051] A further preferred embodiment is a circular structure with a centrally machined hole and a certain thickness, where the radius of the central hole is greater than or equal to the radius of the central hole of the outermost grating assembly, and its radius does not affect the focusing of the grating assembly. More preferably, the insulation ring is made of a relatively loose graphite material; specific examples can be found in existing graphite insulation structures, as long as they effectively prevent heat leakage from the eutectic point crucible.

[0052] In this invention, the grating assembly and the central hole of the heat-insulating grating structure are coaxially arranged, and are also coaxially arranged with the center of the aiming cavity of the rhenium-carbon eutectic crucible.

[0053] This invention utilizes the rhenium-carbon eutectic point (2474℃) for calibration, with the rhenium-carbon eutectic point crucible providing the reference temperature; the specific structure is existing technology.

[0054] The displacement mechanism of this invention is used to move when the radiation thermometer being calibrated is aligned and focused, ensuring that the radiation thermometer can move freely to different positions. For specific structure, please refer to existing structures that provide the movement function.

[0055] The present invention is as follows Figure 4 As shown, a method for calibrating a radiation thermometer is provided, comprising the following steps:

[0056] The first step is to set up the temperature control curve.

[0057] The temperature control curve for this step is as follows: temperature rises from room temperature to temperature A, temperature rises from temperature A to temperature C and holds for a certain time, temperature rises from temperature C to temperature D and holds for a certain time, temperature drops from temperature D to temperature C and holds for a certain time, and temperature drops from temperature C to room temperature. Temperature A is 800℃~850℃, temperature C is 30℃~35℃ below the rhenium-carbide eutectic temperature, and temperature D is 25℃~30℃ above the rhenium-carbide eutectic temperature. Temperature C is held for at least 10 minutes, and temperature D is held for 10 minutes~15 minutes.

[0058] Further preferably, in this step, during the process of raising the temperature from A to C, the temperature is first raised from A to B and held for a certain period of time, and then raised from B to C, wherein the temperature of B is 15°C to 25°C lower than the temperature of C. More preferably, the temperature is raised from A to B at a rate of less than 20°C / min, held at B for at least 1 hour, and then raised from B to C at a rate of less than 20°C / min.

[0059] Further optimization involves raising the temperature from C to D within 3–5 minutes in this step.

[0060] Further preferably, in this step, the temperature is reduced from temperature D to temperature C at a rate of less than 20°C / min.

[0061] Further preferably, in this step, during the process of cooling from temperature C to room temperature, the temperature is first lowered from temperature C to temperature B and held for a certain period of time, then lowered from temperature B to temperature A, and then naturally cooled from temperature A to room temperature. More preferably, the temperature is lowered from temperature C to temperature B at a rate of less than 20°C / min, held at temperature B for at least 10 minutes, and then lowered from temperature B to temperature A at a rate of less than 20°C / min.

[0062] The second step is the preparation steps before calibration.

[0063] This step involves a pre-calibration check of the calibration equipment; see the Existing Equipment Check section for details.

[0064] Including but not limited to the following:

[0065] ① Check whether the water and electricity supply in the laboratory is normal;

[0066] ② Check whether the high-temperature blackbody source system is normal, such as whether the vacuum filling system is connected in series with two argon cylinders and connected to the flow controller, etc.

[0067] ③ Fix the radiation thermometer to be calibrated on the platform of the displacement mechanism and connect the power supply;

[0068] ④ Ensure that the temperature control sensor, the radiation thermometer, and the high-temperature meter being calibrated are properly and securely connected;

[0069] ⑤ Check if the rhenium-carbon eutectic crucible is intact and wipe away any graphite dust from its surface.

[0070] The third step is to install the rhenium-carbon eutectic crucible and the heat-insulating grating structure.

[0071] Specifically, the following steps are included:

[0072] A3.1 Place the rhenium-carbon eutectic crucible at the center of the inner tube of the blackbody radiation source.

[0073] A3.2 Place the grating assembly and insulation ring on both sides of the rhenium-carbon eutectic crucible in the correct order and orientation.

[0074] In this step, the grating assembly and the insulation ring are pushed into the inner tube of the blackbody radiation source from both sides of the furnace openings until they reach the placed rhenium-carbon eutectic crucible.

[0075] Furthermore, in this step, the insulation ring and the grating assembly are alternately arranged, with the grating assembly located closer to the rhenium-carbon eutectic crucible. The insulation grating structures on both sides of the rhenium-carbon eutectic crucible are symmetrically arranged. The central holes of the grating assembly and the insulation ring are coaxially arranged, and also coaxially arranged with the center of the aiming cavity of the rhenium-carbon eutectic crucible.

[0076] Furthermore, in this step, the grating assembly is a sheet-like circular ring structure with a centrally machined circular hole. The radius of the central hole of the grating assembly decreases as it approaches the rhenium-carbohydrate eutectic crucible. The radius of the central hole of the innermost grating assembly (closest to the rhenium-carbohydrate eutectic crucible) is larger than the radius of the aiming cavity of the rhenium-carbohydrate eutectic crucible, while the radius of the central hole of the outermost grating assembly is 1.5 to 2 times the radius of the aiming cavity of the rhenium-carbohydrate eutectic crucible. The radius of the central hole of the grating assembly increases from the inside to the outside. More preferably, the grating assembly is made of graphite material, which is more compact than the insulation ring and has a thin sheet structure, with a thickness sufficient to ensure the strength required for use.

[0077] In a further preferred embodiment, the insulation ring in this step is a circular ring structure with a centrally machined hole and a certain thickness. The radius of the central hole of the insulation ring is greater than or equal to the radius of the central hole of the outermost grating assembly, and its radius does not affect the focusing of the grating assembly. More preferably, the insulation ring is made of a relatively loose graphite material. Specifically, existing graphite insulation structures can be referenced, as long as they have the function of preventing heat leakage from the eutectic point crucible.

[0078] Step 4: Cold focus.

[0079] In this step, the circular positioning plate is placed on both sides of the furnace opening inside the blackbody radiation source tube, so that the center standard point of the temperature control sensor and the radiation thermometer being calibrated coincides with the center point of the circular positioning plate.

[0080] Step 5: Cleaning the inner cavity of the blackbody radiation source tube.

[0081] This step is a well-known technique in the field. Those skilled in the art can set specific parameters and order according to actual circumstances, including but not limited to the following steps:

[0082] ① Remove the glass window of the heating device;

[0083] ② Turn on the water cooling system and turn on the power switch;

[0084] ③ Turn on the vacuum pump of the vacuum charging system to evacuate the heating device to a vacuum state (-0.1MPa);

[0085] ④ Open the gas cylinder of the vacuum filling system, turn on the filling switch, fill the heating device with argon gas, and then turn off the filling switch;

[0086] ⑤ Turn the vacuum pump back on and evacuate the heating device until it reaches a vacuum state (-0.1MPa);

[0087] ⑥ Open the gas cylinder, turn on the gas filling switch, and fill the blackbody radiation source with argon gas, adjusting the flow meter value to 5L / min.

[0088] Step 6: Thermal focusing.

[0089] Specifically, the following steps are included:

[0090] A6.1. Following the temperature control curve set in step one, raise the blackbody radiation source from room temperature to temperature A.

[0091] A6.2 At temperature A, perform thermal focusing on the radiation thermometer to be calibrated so that the center standard point of the radiation thermometer is aligned with the center point of the field of view of the aiming cavity of the rhenium-carbon eutectic crucible through which the thermal grating structure passes.

[0092] Step 7: Perform temperature control and data acquisition according to the temperature control curve set in Step 1.

[0093] In this step, data acquisition begins after the temperature reaches C, and ends after the temperature drops back to C.

[0094] Furthermore, in this step, data is collected at high frequency to form a data table and store it: the data information includes the collection time x (absolute time or relative time with the start of collection as 0) and the output voltage y of the radiation thermometer being calibrated.

[0095] Step 8: Data processing.

[0096] In this step, the temperature plateau interpretation uses the inflection point calculation method to determine the start and end points of the eutectic reaction. For example... Figure 5 As shown, the specific steps include:

[0097] A8.1. Extract a portion of the data collected in step seven. The extracted data must include either a heating process to temperature D or a cooling process from temperature D.

[0098] A8.2. Perform function fitting on the data extracted in step A8.1 to obtain the time-output value function and time-output value curve of the acquisition time x and the output voltage y of the radiation thermometer being calibrated.

[0099] Furthermore, this step employs the least squares method for function fitting. Curve and function fitting are well-known techniques in this field and will not be elaborated upon here.

[0100] A8.3. Take the second derivative of the time-output value function fitted in step A8.2 to obtain two inflection points.

[0101] Furthermore, this step is a well-known technique in the field and will not be described in detail here.

[0102] A8.4. Using the two inflection points obtained in step A8.3 as the starting and ending points on the time-output value curve fitted in step A8.2, obtain the voltage difference between the two points.

[0103] A8.5. Compare the voltage difference obtained in step A8.4 or step A8.6 with the differential voltage value of the radiation thermometer being calibrated. If the voltage difference is less than or equal to the differential voltage value, proceed to step A8.7. If the voltage difference is greater than the differential voltage value, proceed to step A8.6.

[0104] In this step, if the difference between the initial and final voltages is less than or equal to the differential voltage value in the instruction manual of the radiation thermometer being calibrated, it proves that the temperature drift is within an acceptable range during the formation of the temperature plateau.

[0105] A8.6 Narrow the time range between the start and end points, and re-mark the start and end points on the time-output value curve to obtain the voltage difference between the two points. Repeat steps A8.5 to A8.6 until the voltage difference is less than or equal to the differential voltage value.

[0106] In this step, the selected data segment should be moved as close to the center as possible, and the start and end points should be moved to a relatively flat area.

[0107] A8.7 Obtain the time interval in which the voltage difference is less than or equal to the differential voltage value, calculate the average voltage value of the time interval, and obtain the temperature value corresponding to the radiation thermometer being calibrated based on the average voltage value. The difference between this temperature value and the rhenium-carbon eutectic point temperature is the temperature calibration error value of the radiation thermometer being calibrated.

[0108] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. A radiation thermometer calibration device, comprising a high-temperature blackbody source system, a rhenium-carbon eutectic crucible, and a displacement mechanism, wherein the high-temperature blackbody source system includes a temperature control system, a blackbody radiation source, a vacuum filling system, a water cooling system, and a data acquisition device, and the temperature control system includes a temperature sensor and a heating device; characterized in that: The rhenium-carbon eutectic crucible is located at the center of the inner cavity of the blackbody radiation source. A set of heat-insulating grating structures is set on each side of the rhenium-carbon eutectic crucible. The radiation thermometer to be calibrated is fixedly installed on the displacement mechanism. The radiation thermometer to be calibrated and the temperature control sensor are respectively set at the inlets on both sides of the inner cavity of the blackbody radiation source. The radiation thermometer to be calibrated is aligned with the aiming cavity of the rhenium-carbon eutectic crucible. The radiation thermometer to be calibrated is connected to the data acquisition equipment via a data cable. The temperature control system has a preset temperature control curve. The system controls the heating device according to the temperature control curve to control the temperature of the blackbody radiation source during the calibration process. The temperature control curve is as follows: room temperature rises to temperature A, temperature rises from temperature A to temperature C and holds for a certain time, temperature rises from temperature C to temperature D and holds for a certain time, temperature drop from temperature D to temperature C and holds for a certain time, and temperature drop from temperature C to room temperature. Temperature A is 800℃~850℃, temperature C is 30℃~35℃ below the rhenium-carbide eutectic temperature, and temperature D is 25℃~30℃ above the rhenium-carbide eutectic temperature. Temperature C is held for at least 10 minutes, and temperature D is held for 10 minutes~15 minutes.

2. The radiation thermometer calibration device according to claim 1, characterized in that: The heat-insulating grating structure consists of multiple heat-insulating rings and grating components arranged alternately, with the grating component located on the side closer to the rhenium-carbon eutectic crucible, and the heat-insulating grating structures on both sides of the rhenium-carbon eutectic crucible arranged symmetrically.

3. The radiation thermometer calibration device according to claim 2, characterized in that: The grating assembly is a sheet-like annular structure with a centrally machined circular hole. The radius of the grating assembly's central hole is smaller closer to the rhenium-carbon eutectic crucible. The radius of the central hole of the innermost grating assembly is larger than the radius of the aiming cavity of the rhenium-carbon eutectic crucible, and the radius of the central hole of the outermost grating assembly is 1.5 to 2 times the radius of the aiming cavity of the rhenium-carbon eutectic crucible. The radius of the central hole of the grating assembly increases from the inside to the outside.

4. The radiation thermometer calibration device according to claim 3, characterized in that: The insulation ring is a circular ring structure with a centrally machined hole and a certain thickness. The radius of the central hole of the insulation ring is greater than or equal to the radius of the central hole of the outermost grating assembly.

5. The radiation thermometer calibration device according to claim 4, characterized in that: The grating assembly and the central hole of the insulation ring are coaxially arranged, and are also coaxially arranged with the center of the aiming cavity of the rhenium-carbon eutectic crucible.

6. A radiation thermometer calibration device according to any one of claims 1-5, characterized in that: In the aforementioned temperature control curve, the temperature rises from C to D within 3–5 minutes.

7. A radiation thermometer calibration device according to claim 6, characterized in that: In the temperature control curve, during the process of rising from temperature A to temperature C, the temperature is first raised from temperature A to temperature B and held for a certain period of time, and then raised from temperature B to temperature C, wherein temperature B is 15°C to 25°C lower than temperature C. More preferably, the temperature is raised from temperature A to temperature B at a rate of less than 20°C / min, and held at temperature B for at least 1 hour to better ensure uniform system temperature, and then raised from temperature B to temperature C at a rate of less than 20°C / min. Temperature D is reduced to temperature C at a rate below 20°C / min; or During the process of cooling from temperature C to room temperature, the temperature is first lowered from C to temperature B and held for a certain period of time, then lowered from temperature B to temperature A, and then naturally cooled from temperature A to room temperature. More preferably, the temperature is lowered from C to temperature B at a rate of less than 20°C / min, held at temperature B for at least 10 minutes, and then lowered from temperature B to temperature A at a rate of less than 20°C / min.

8. A method for calibrating a radiation thermometer, characterized in that, Includes the following steps: The first step is to set up the temperature control curve. The temperature control curve is as follows: temperature rises from room temperature to temperature A, temperature rises from temperature A to temperature C and holds for a certain time, temperature rises from temperature C to temperature D and holds for a certain time, temperature drops from temperature D to temperature C and holds for a certain time, and temperature drops from temperature C to room temperature. Temperature A is 800℃~850℃, temperature C is 30℃~35℃ below the rhenium-carb eutectic temperature, temperature D is 25℃~30℃ above the rhenium-carb eutectic temperature, temperature C is held for at least 10 minutes, and temperature D is held for 10 minutes~15 minutes. The second step is the preparation steps before calibration. The third step is the installation of the rhenium-carbon eutectic crucible and the heat-insulating grating structure. A3.1 Place the rhenium-carbon eutectic crucible at the center of the inner tube of the blackbody radiation source; A3.2 Place the grating assembly and the insulation ring on both sides of the rhenium-carbon eutectic crucible in sequence and direction. The insulation ring and the grating assembly are set alternately. The grating assembly is on the side closer to the rhenium-carbon eutectic crucible. The insulation grating structures on both sides of the rhenium-carbon eutectic crucible are set symmetrically. The fourth step is cold focusing. Place the circular positioning plate on both sides of the furnace opening inside the blackbody radiation source tube so that the center standard point of the temperature control sensor and the radiation thermometer being calibrated coincides with the center point of the circular positioning plate. Step 5: Cleaning the inner cavity of the blackbody radiation source tube; Step 6: Thermal focusing. A6.

1. Following the temperature control curve set in step one, raise the blackbody radiation source from room temperature to temperature A; A6.2 At temperature A, perform thermal focusing on the radiation thermometer to be calibrated so that the center standard point of the radiation thermometer to be calibrated is aligned with the center point of the field of view of the aiming cavity of the rhenium-carbon eutectic crucible through which the heat-insulating grating structure passes. Step 7: Perform temperature control and data acquisition according to the temperature control curve set in Step 1; Step 8: Data processing. A8.

1. Extract a portion of the data collected in step seven. The extracted data must include either a heating process to temperature D or a cooling process from temperature D. A8.2 Perform function fitting on the data extracted in step A8.1 to obtain the time-output value function and time-output value curve of the acquisition time x and the output voltage y of the radiation thermometer under calibration; A8.

3. Take the second derivative of the time-output value function fitted in step A8.2 to obtain two inflection points; A8.

4. Using the two inflection points obtained in step A8.3 as the starting and ending points on the time-output value curve fitted in step A8.2, obtain the voltage difference between the two points. A8.

5. Compare the voltage difference obtained in step A8.4 or step A8.6 with the differential voltage value of the radiation thermometer being calibrated. If the voltage difference is less than or equal to the differential voltage value, proceed to step A8.

7. If the voltage difference is greater than the differential voltage value, proceed to step A8.

6. A8.6 Narrow the time range between the start and end points, re-mark the start and end points on the time-output value curve, and obtain the voltage difference between the two points. Repeat steps A8.5 to A8.6 until the voltage difference is less than or equal to the differential voltage value. A8.7 Obtain the time interval in which the voltage difference is less than or equal to the differential voltage value, calculate the average voltage value of the time interval, and obtain the temperature value corresponding to the radiation thermometer being calibrated based on the average voltage value. The difference between this temperature value and the rhenium-carbon eutectic point temperature is the temperature calibration error value of the radiation thermometer being calibrated.

9. A method for calibrating a radiation thermometer according to claim 8, characterized in that: In the third step, the grating assembly is a sheet-like circular ring structure with a centrally machined circular hole. The radius of the grating assembly's central hole is smaller the closer it is to the rhenium-carbon eutectic crucible. The radius of the central hole of the innermost grating assembly is larger than the radius of the aiming cavity of the rhenium-carbon eutectic crucible, and the radius of the central hole of the outermost grating assembly is 1.5 to 2 times the radius of the aiming cavity of the rhenium-carbon eutectic crucible. The radius of the central hole of the grating assembly increases from the inside to the outside. In the third step, the insulation ring is a circular structure with a certain thickness and a centrally machined circular hole. The radius of the central hole of the insulation ring is greater than or equal to the radius of the central hole of the outermost grating assembly; or In the third step, the grating assembly and the central hole of the insulation ring are coaxially arranged, and are also coaxially arranged with the center of the aiming cavity of the rhenium-carbon eutectic crucible.

10. A method for calibrating a radiation thermometer according to claim 9, characterized in that: In the first step, during the process of raising the temperature from A to C, the temperature is first raised from A to B and held for a certain period of time, and then raised from B to C, wherein the temperature of B is 15°C to 25°C lower than the temperature of C. More preferably, the temperature is raised from A to B at a rate of less than 20°C / min, held at B for at least 1 hour, and then raised from B to C at a rate of less than 20°C / min. In the first step, the temperature is raised from C to D within 3 to 5 minutes; In the first step, the temperature is reduced from D at a rate of less than 20°C / min to C. In the first step, during the process of cooling from temperature C to room temperature, the temperature is first lowered from temperature C to temperature B and held for a certain period of time, then lowered from temperature B to temperature A, and then naturally cooled from temperature A to room temperature. More preferably, the temperature is lowered from temperature C to temperature B at a rate of less than 20°C / min, held at temperature B for at least 10 minutes, and then lowered from temperature B to temperature A at a rate of less than 20°C / min; or In the seventh step, after the temperature reaches C, data acquisition begins; after the temperature drops to C, data acquisition ends.

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