A portable blackbody furnace for radiation pyrometer calibration

Abstract

The application provides a portable black body furnace for radiation pyrometer calibration, which comprises a top cover plate, a bottom cover plate, a left cover plate, a right cover plate, a front mounting plate, a rear mounting plate, electric heating tubes, heating tube sleeves, a center sample tube and ten parts of graphite rods. A square quartz glass with a size matched with the fixing groove of the front mounting plate is inserted, a thermocouple is inserted from the middle hole groove of the rear mounting plate to the rear end hole groove of the graphite rod, and the four electric heating tubes are powered to heat. The temperature at the bottom of the hollow cavity of the graphite rod is measured by the thermocouple, and the temperature controller receives the feedback signal of the thermocouple, and then a radiation pyrometer calibration device similar to a black body furnace is obtained. The portable black body furnace device for radiation pyrometer calibration has the advantages that: a simple and portable radiation pyrometer calibration device is provided, the shortcomings of a traditional black body furnace, such as large volume, inconvenience in carrying and transportation, are improved, and the temperature stability performance is improved by using high-temperature-resistant quartz plates to isolate air.

Description

Technical Field

[0001] This invention relates to a temperature calibration device, specifically a portable blackbody furnace device for calibrating a radiation pyrometer. Background Technology

[0002] The primary function of a blackbody furnace is to generate standard radiation at a specific temperature. Therefore, it is mainly used in temperature metrology to calibrate various radiation thermometers, such as optical pyrometers, infrared thermometers, and infrared thermal imagers. In the field of measurement, blackbodies are used to measure the spectral emission, absorption, and reflection characteristics of materials. In temperature metrology, the correlation between blackbody radiation and temperature is mainly utilized, thus requiring a higher emissivity for the blackbody. In radiation thermometry, blackbodies are commonly used in emissivity measurement experiments. This experimental setup supports energy-based spectral emissivity measurement methods. The ratio of the radiation energy curves of the sample and the reference blackbody at the same temperature is the emissivity; therefore, when using this setup for spectral emissivity measurement, the blackbody is used as a standard reference. However, current standard blackbody furnaces suffer from drawbacks such as high power consumption, large size, slow heating, and high cost, especially failing to meet the requirements of on-site calibration. Therefore, there is an urgent need for a blackbody furnace that is small in size, low in power consumption, and heats up quickly to meet the requirements of on-site calibration temperatures. Summary of the Invention

[0003] The main technical problem solved by this invention is to propose a portable device for calibrating radiation pyrometers, thereby solving the current technical problem that blackbodies are not convenient to carry in radiation pyrometer calibration.

[0004] To solve the above technical problems, the present invention adopts the following technical solution: a portable blackbody furnace for calibrating a radiation pyrometer, comprising: an upper cover plate, a lower cover plate, a left cover plate, a right cover plate, a front mounting plate, a rear mounting plate, four heating tubes, four heating tube sleeves, a central sample tube, and a graphite rod; the rear mounting plate is provided with mounting holes for mounting the four heating tube sleeves and the central sample tube, and these mounting holes are all of two stages, with the diameter of the inner stage matching the outer diameter of the corresponding mounting component, and the diameter of the outer stage matching the inner diameter of the corresponding mounting component; the front mounting plate is provided with mounting holes for mounting the central sample tube and mounting holes for mounting the four heating tube sleeves. The mounting hole for the central sample tube also includes two stages: the diameter of the inner stage matches the outer diameter of the central sample tube, and the diameter of the outer stage matches the inner diameter of the central sample tube. Slots are provided in three directions on the mounting hole of the central sample tube on the front mounting plate, allowing a quartz plate to be inserted and block the mounting hole on the front mounting plate. The graphite rod is placed inside the central sample tube, with its front end flush with the front end of the central sample tube. Both ends of the graphite rod have central holes that are not connected; the diameter of the front central hole is larger than the diameter of the rear central hole. A thermocouple is fixed inside the rear central hole, and the temperature signal from the thermocouple is transmitted to the temperature controller. The length-to-diameter ratio of the front central hole is greater than 6.

[0005] Furthermore, the heating element comprises two sections, each with a different diameter. The front end is a cylinder with a length of 100mm and a diameter of 6mm, and the rear end consists of two parallel cylinders with a radius of 1mm and a length of 50mm. The heating power is 200W.

[0006] The graphite rod has a diameter of 18mm and a length of 50mm. It has two cylindrical through-holes of different diameters inside. The central hole at the front end has a diameter of 7mm and a depth of 42mm, while the central hole at the rear end has a diameter of 1mm and a depth of 5mm. The length-to-diameter ratio of the central hole in the graphite rod is 6, which can be considered a blackbody. In use, the graphite rod is inserted into the central sample tube, keeping the plane of the cylindrical through-hole at the front end of the graphite rod flush with the front end plane of the central sample tube. The central sample tube is cylindrical in shape, with a height of 100mm and a diameter of 25mm. It has a cylindrical through-hole with a diameter of 19mm inside.

[0007] The front mounting plate is rectangular, 100mm long and wide, and 8mm thick. Three 2.4mm holes on the side are used to secure the mounting plate. The rear end of the plate has five cylindrical holes. The central hole has two levels: the inner level has an inner diameter of 25mm and a depth of 5mm, and the outer level has an inner diameter of 19mm and a depth of 3mm, used to secure the central sample tube. The other four cylindrical holes are all 10mm in diameter, evenly distributed at the four corners of the central hole, and each has a depth of 8mm, used to secure four heating tube sleeves. The central cylindrical hole at the front end of the plate is the same diameter as the cylindrical hole at the rear end, and three metal slots are distributed around its perimeter. The quartz plate is 40mm long, 40mm wide, and 2mm high, and can be inserted into the metal slots.

[0008] Furthermore, the rear mounting plate has a rectangular panel with a length and width of 100mm and a height of 8mm. Three 2.4mm holes on the side are used to fix the mounting plate. The rear end of the panel has five cylindrical holes, with a central hole diameter of 1.5mm and a depth of 3mm, aligned with the rear end hole diameter of the graphite rod on the same horizontal reference line. At the four corners of this central hole are cylindrical holes with a diameter of 10mm and a depth of 8mm, corresponding to the four cylindrical holes on the rear surface of the front mounting plate on the same horizontal reference line. The front end has five cylindrical holes, with a central hole diameter of 25mm and a depth of 5mm. At the center of each hole is a 1.5mm diameter cylindrical hole, the same diameter as the central hole on the rear end. The central hole on the front end, in conjunction with the central hole on the rear end of the front mounting plate, is used to fix the central sample tube. The other four cylindrical holes, in conjunction with the cylindrical holes at the four corners of the rear end of the front mounting plate, are used to fix the four heating tube sleeves.

[0009] Furthermore, the upper and lower cover plates have identical shape parameters; their length is 106mm, width is 100mm, and height is 8mm; their front end face has two cylindrical through holes with an outer diameter of 4.3mm, a depth of 2.3mm, an inner diameter of 2.4mm, and a depth of 5.7mm; their rear end face has two cylindrical through holes, which are connected to the two cylindrical through holes on the front end face; both ends of the upper side of the cover plate have two cylindrical through holes with the same diameter and depth as the front end face, and the middle hole has a diameter of 2.4mm and a depth of 3mm; the lower side has three holes, each with a diameter of 2.4mm and a depth of 3mm.

[0010] The two cover plates have identical shape parameters; their length is 116mm, width is 106mm, and height is 5mm; their front end face has eight through holes with an outer diameter of 4.3mm, a depth of 2.3mm, an inner diameter of 2.4mm, and a depth of 2.7mm; their rear end face has eight cylindrical through holes, which are the same eight through holes connected to the eight cylindrical through holes on the front end face.

[0011] The advantages of this invention are as follows: This portable blackbody furnace is small in size, has a temperature range from room temperature to 1000℃, and a power of 1KW, making it suitable for field use. The quartz plate is light-transmitting and heat-resistant, reducing airflow and thus minimizing measurement errors; the graphite rod is heated quickly and efficiently via a heating tube; the thermocouple continuously measures the graphite rod's temperature, precisely controlling its temperature changes; the aspect ratio of the central hole at the front end of the graphite rod allows it to be closer to the theoretical blackbody; it is inexpensive and easy to carry. Attached Figure Description

[0012] Figure 1 An assembly rendering of a portable blackbody furnace for calibrating a radiation pyrometer;

[0013] Figure 2 This is a schematic diagram of an electric heating element;

[0014] Figure 3 This is a schematic diagram of the heating tube sleeve;

[0015] Figure 4 Schematic diagram of a graphite rod;

[0016] Figure 5 A schematic diagram of the central sample tube;

[0017] Figure 6 This is a schematic diagram of the rear mounting plate;

[0018] Figure 7 This is a schematic diagram of the front mounting plate;

[0019] Figure 8 Schematic diagram of the upper cover plate and the lower cover plate;

[0020] Figure 9 Schematic diagram of the left and right cover plates;

[0021] Figure 10 This is a schematic diagram of the calibration process for a radiation pyrometer.

[0022] In the figure, 1 is the front mounting plate; 2 is the graphite rod; 3 is the upper cover plate; 4 is the left cover plate; 5 is the right cover plate; 6 is the lower cover plate; 7 is the rear mounting plate; 8 is the heating tube; 9 is the heating tube sleeve; 10 is the central sample tube; 11 is the front through hole; 12 is the rear through hole. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] The four heating tubes consist of two sections, each with a different diameter. The front end is a 100mm long cylinder with a 6mm diameter, and the rear end consists of two parallel cylinders with a radius of 1mm and a length of 50mm. The heating power is 200W, and the heating principle is resistance heating. During installation, the front ends of the four heating tubes are inserted into the four heating tube sleeves, while the rear cylinders are exposed outside the heating tube sleeves. Power is then applied. The internal closed-loop circuit heats up, thereby heating the heating tube sleeves, which in turn heats the central sample tube, ultimately heating the graphite rod. The heating temperature can range from room temperature to 1000℃.

[0025] A temperature measuring thermocouple is fixed to the end of the graphite rod through an opening, and the temperature signal of the thermocouple is transmitted to the temperature controller.

[0026] The graphite rod has a diameter of 18mm and a length of 50mm. It has two cylindrical through-holes of different diameters inside. The central hole at the front end has a diameter of 7mm and a depth of 42mm, while the central hole at the rear end has a diameter of 1mm and a depth of 5mm. The length-to-diameter ratio of the central hole in the graphite rod is 6, which can be considered as a blackbody. In use, the graphite rod is inserted into the central sample tube, ensuring that the plane of the cylindrical through-hole at the front end of the graphite rod is flush with the front end plane of the central sample tube.

[0027] The central sample tube is cylindrical in shape, with a height of 100mm and a diameter of 25mm. It has an internal cylindrical through-hole with a diameter of 19mm. During use, the central sample tube is fixed into a matching groove on the rear end face of the front mounting plate.

[0028] The heating tube sleeve is cylindrical in shape, with a height of 100mm and a diameter of 10mm. It has a 6mm diameter cylindrical through-hole inside. During use, the four heating tube sleeves are fixed into four matching grooves on the rear end face of the front mounting plate.

[0029] The front mounting plate is rectangular, 100mm long and wide, and 8mm thick. Three 2.4mm holes on the side are used to secure the mounting plate. The rear end of the plate has five cylindrical holes. The central hole has two levels: the inner level has an inner diameter of 25mm and a depth of 5mm, and the outer level has an inner diameter of 19mm and a depth of 3mm, used to secure the central sample tube. The other four cylindrical holes are all 10mm in diameter, evenly distributed at the four corners of the central hole, and each has a depth of 8mm, used to secure four heating tube sleeves. The central cylindrical hole at the front end of the plate is the same diameter as the cylindrical hole at the rear end, and three metal slots are distributed around its perimeter. The quartz plate is 40mm long, 40mm wide, and 2mm high, and can be inserted into the metal slots.

[0030] The rear mounting plate is a rectangular panel with a length and width of 100mm and a height of 8mm.

[0031] There are three 2.4mm holes on the side for securing the mounting plate. The rear end of the panel has five cylindrical holes, with a central hole of 1.5mm diameter and a depth of 3mm, aligned with the rear hole of the graphite rod on the same horizontal reference line. At the four corners of this central hole are cylindrical holes of 10mm diameter and a depth of 8mm, corresponding to the four cylindrical holes on the rear surface of the front mounting plate on the same horizontal reference line. The front end face has five cylindrical holes, with a central hole of 25mm diameter and a depth of 5mm. At the center of each hole is a 1.5mm diameter cylindrical hole, the same diameter as the central hole on the rear end face. The central hole on the front end face, in conjunction with the central hole on the rear end face of the front mounting plate, is used to secure the central sample tube. The other four cylindrical holes, in conjunction with the four corner holes on the rear end face of the front mounting plate, are used to secure the four heating tube sleeves.

[0032] The upper and lower cover plates are identical in shape. They are 106mm long, 100mm wide, and 8mm high. The front face has two cylindrical through holes with an outer diameter of 4.3mm, a depth of 2.3mm, an inner diameter of 2.4mm, and a depth of 5.7mm. The rear face has two cylindrical through holes, which are connected to the two cylindrical through holes on the front face. The upper side of the cover plate has two cylindrical through holes at both ends with the same diameter and depth as the front face, with the middle hole having a diameter of 2.4mm and a depth of 3mm. The lower side has three holes, each with a diameter of 2.4mm and a depth of 3mm.

[0033] The two cover plates are identical in shape and parameters. They are 116mm long, 106mm wide, and 5mm high. The front face has eight through holes with an outer diameter of 4.3mm, a depth of 2.3mm, an inner diameter of 2.4mm, and a depth of 2.7mm. The rear face has eight cylindrical through holes, which are connected to the eight cylindrical through holes on the front face.

[0034] A schematic diagram of the calibration process for a radiation pyrometer is shown below. Figure 10 As shown, the device includes a radiation pyrometer calibration apparatus consisting of a heating system, a focusing system, a spectrometer, and optical fibers. Graphite rods are materials with stable radiation energy, are heat-resistant, and easy to polish. Their radiation energy output is very stable under high-temperature conditions, making them suitable as approximate blackbodies. After mounting a quartz plate, the graphite rod is heated by an electric heating tube. The temperature of the through-hole 12 at the rear end of the graphite rod is then measured by a thermocouple, and the temperature value is fed back to a temperature controller, which controls the temperature of the graphite rod. Once a certain temperature is reached, the spectral information of the graphite rod is measured using the spectrometer, and its energy emission curve is saved on a PC. The radiation energy curve of the sample to be calibrated is then measured, and the ratio of the radiation energy curves is used to calibrate the sample's radiation pyrometer.

[0035] Step 1: Connect and fix the front mounting plate 1, upper cover plate 3, lower cover plate 6, left cover plate 4, and right cover plate 5 with bolts and matching threads.

[0036] Step 2: Insert the central sample tube 10 and the four heating tube sleeves 9 into the matching grooves on the rear end face of the front mounting plate 1. Then connect the rear mounting plate 7 and the assembly installed in Step 1 with bolts and matching threads. At this time, the five grooves and through holes on the front end face of the rear mounting plate 7 are exactly matched with the central sample tube 10 and the four heating tube sleeves 9, thus fixing the five tubes.

[0037] Step 3: Insert the four heating elements 8 into the four matching through holes on the rear end face of the rear mounting plate 7, and continue until they are fixed on the rear end face of the front mounting plate 1.

[0038] Step 4: Insert the graphite rod 2 into the middle through hole on the front end face of the front mounting plate 1 until the front end face of the graphite rod 2 is flush with the front end face of the front mounting plate 1.

[0039] Step 5: Insert the quartz plate into the gap inside the three fixing metal slots on the front end of the mounting plate 1 to ensure that the air and the graphite rod do not come into contact, thereby reducing measurement errors.

[0040] Step 6: Insert the thermocouple into the rear through hole 12 of the graphite rod 2 through the middle hole of the rear end face of the rear mounting plate 7, and fix the thermocouple.

[0041] Step 7: Adjust the dark noise, integration time and other parameters of the spectrometer to ensure that the spectrometer can stably and accurately measure the radiation energy of graphite rod 2.

[0042] Step 8: Align the focusing system in the spectral measurement system with the center of the reference blackbody furnace. Connect both ends of the optical fiber to the focusing system and the spectrometer. Connect the wires to the rear ends of the four heating tubes 8. Turn on the power to start heating the graphite rod 2. When heated to a certain temperature, save the energy curve on the PC. By comparing it with the sample, the temperature calibration function can be achieved.

Claims

1. A portable blackbody furnace for calibrating a radiation pyrometer, the blackbody furnace comprising: an upper cover plate, a lower cover plate, a left cover plate, a right cover plate, a front mounting plate, a rear mounting plate, four heating tubes, four heating tube sleeves, a central sample tube, and a graphite rod; the rear mounting plate is provided with mounting holes for mounting the four heating tube sleeves and the central sample tube, and these mounting holes are all of two stages, the diameter of the inner stage matching the outer diameter of the corresponding mounting component, and the diameter of the outer stage matching the inner diameter of the corresponding mounting component; the front mounting plate is provided with mounting holes for mounting the central sample tube and mounting grooves for mounting the four heating tube sleeves, the central sample tube, and a graphite rod. The sample tube mounting hole also includes two stages: the diameter of the inner stage matches the outer diameter of the central sample tube, and the diameter of the outer stage matches the inner diameter of the central sample tube. Slots are provided in three directions on the mounting hole of the central sample tube on the front mounting plate to fit and engage a quartz plate, thus blocking the mounting hole on the front mounting plate. The graphite rod is placed inside the central sample tube, with its front end flush with the front end of the central sample tube. Both ends of the graphite rod have central holes that are not connected; the diameter of the front central hole is larger than the diameter of the rear central hole. A thermocouple is fixed inside the rear central hole, and the temperature signal from the thermocouple is transmitted to the temperature controller. The heating element consists of two sections, each with a different diameter. The front end is a cylinder with a length of 100mm and a diameter of 6mm, and the rear end consists of two parallel cylinders with a radius of 1mm and a length of 50mm. The heating power is 200W. The graphite rod has a diameter of 18mm and a length of 50mm. It has two cylindrical through-holes of different diameters inside. The central hole at the front end has a diameter of 7mm and a depth of 42mm, while the central hole at the rear end has a diameter of 1mm and a depth of 5mm. The length-to-diameter ratio of the central hole in the graphite rod is 6, which can be considered a blackbody. In use, the graphite rod is inserted into the central sample tube, keeping the plane of the cylindrical through-hole at the front end of the graphite rod flush with the front end plane of the central sample tube. The central sample tube is cylindrical in shape, with a height of 100mm and a diameter of 25mm. It has a cylindrical through-hole with a diameter of 19mm inside. The front mounting plate is a rectangular panel with a length and width of 100mm and a thickness of 8mm. There are three 2.4mm holes on the side for fixing this mounting plate; The rear end of the panel has five cylindrical apertures. The central aperture has two levels: the inner level has an inner diameter of 25mm and a depth of 5mm, and the outer level has an inner diameter of 19mm and a depth of 3mm, used to fix the central sample tube. The other four cylindrical apertures are all 10mm in diameter, evenly distributed at the four corners of the central aperture, and are all 8mm deep, used to fix the four heating tube sleeves. The central cylindrical aperture at the front end of the panel is the same as the cylindrical aperture at the rear end, and there are three metal slots around it. The quartz plate is 40mm long and wide and 2mm high, which can be matched and inserted into the metal slots.

2. The portable blackbody furnace for calibrating a radiation pyrometer as described in claim 1, characterized in that, The rear mounting plate has a rectangular shape, with a length and width of 100mm and a height of 8mm. Three 2.4mm holes on the side are used to fix the mounting plate. The rear end of the panel has five cylindrical holes, with a central hole diameter of 1.5mm and a depth of 3mm, aligned with the rear end hole of the graphite rod on the same horizontal reference line. At the four corners of this central hole are cylindrical holes with a diameter of 10mm and a depth of 8mm, corresponding to the four cylindrical holes on the rear surface of the front mounting plate on the same horizontal reference line. The front end has five cylindrical holes, with a central hole diameter of 25mm and a depth of 5mm. At the center of each hole is a 1.5mm diameter cylindrical hole, the same diameter as the central hole on the rear end. The central hole on the front end, in conjunction with the central hole on the rear end of the front mounting plate, is used to fix the central sample tube. The other four cylindrical holes, in conjunction with the cylindrical holes at the four corners of the rear end of the front mounting plate, are used to fix the four heating tube sleeves.

3. A portable blackbody furnace for calibrating a radiation pyrometer as described in claim 1, characterized in that, The upper and lower cover plates have identical shape parameters; their length is 106mm, width is 100mm, and height is 8mm; their front end face has two cylindrical through holes with an outer diameter of 4.3mm, a depth of 2.3mm, an inner diameter of 2.4mm, and a depth of 5.7mm; their rear end face has two cylindrical through holes, which are connected to the two cylindrical through holes on the front end face; both ends of the upper side of the cover plate have two cylindrical through holes with the same diameter and depth as the front end face, and the middle hole has a diameter of 2.4mm and a depth of 3mm; the lower side has three holes, each with a diameter of 2.4mm and a depth of 3mm. The two cover plates have identical shape parameters; their length is 116mm, width is 106mm, and height is 5mm; their front end face has eight through holes with an outer diameter of 4.3mm, a depth of 2.3mm, an inner diameter of 2.4mm, and a depth of 2.7mm; their rear end face has eight cylindrical through holes, which are the same eight through holes connected to the eight cylindrical through holes on the front end face.

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