Ultralow-temperature blackbody furnace and calibration method thereof

Abstract

The invention relates to an ultralow-temperature blackbody furnace and a calibration method thereof, and belongs to the field of low-temperature infrared radiation calibration. A low-temperature storage box and an equipment mounting and positioning seat are arranged in a calibration cabin, infrared equipment to be calibrated is fixed through the equipment mounting and positioning seat, and connection and control with the outside of the cabin are realized through a cabin-penetrating electric connector; low-temperature liquid is injected into the low-temperature storage tank to provide a low-temperature source, the wall temperature sensor, the infrared light transmitting material, the vacuum chamber and the wall surface of the black body form the low-temperature black body with accurate wall temperature measurement, the low-temperature black body capable of providing a surface radiation source and a line radiation source according to calibration needs is obtained, and the low-temperature black body has the advantages of being multifunctional and convenient to use; according to the invention, in the process of gradually reaching heat balance, blackbody radiation sources with different low temperatures changing along with time can be output; and the line radiation source can provide standard blackbody radiation at different temperatures at the same time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of low-temperature infrared radiation calibration, and particularly relates to an ultralow-temperature blackbody furnace and a calibration method thereof. BACKGROUND

[0002] A blackbody is an idealized object that absorbs all electromagnetic radiation falling on it and does not reflect or emit any light, and is often used as a standard object for thermal radiation research. Blackbodies can be divided into low-temperature, medium-temperature and high-temperature blackbodies according to temperature, wherein the lower limit temperature of a low-temperature blackbody is equal to or lower than the ambient temperature; the lower limit temperature of a medium-temperature blackbody is higher than the ambient temperature and lower than 1200 DEG C; and the temperature of a high-temperature blackbody is higher than 1200 DEG C. At present, the lower limit temperature of a commonly used low-temperature blackbody on the market is about -50 DEG C, and a blackbody radiation source with a lower temperature cannot be provided at present.

[0003] In order to further expand the low-temperature measurement range of infrared equipment, an ultralow-temperature blackbody with a temperature lower than -50 DEG C and below is needed as a radiation source required for low-temperature calibration. SUMMARY

[0004] The present application aims to provide an ultralow-temperature blackbody furnace and a calibration method thereof, wherein the lowest blackbody temperature can reach about 4.5K through the structural design of the low-temperature blackbody furnace, and a surface radiation source with a fixed-point temperature and a linear radiation source with a step temperature can be provided as needed.

[0005] The above-mentioned object of the present application is mainly achieved by the following technical scheme:

[0006] An ultralow-temperature blackbody furnace comprises a low-temperature filling port, a low-temperature gas discharge port, a cabin gas discharge port, a device mounting and positioning seat, a cabin gas inlet, a low-temperature storage tank, a low-temperature liquid, a blackbody wall surface and a calibration cabin, wherein the low-temperature storage tank and the device mounting and positioning seat are arranged in the calibration cabin, the infrared equipment to be calibrated is fixed through the device mounting and positioning seat, and is electrically connected to the outside of the cabin.

[0007] The low-temperature storage tank is provided with the low-temperature filling port and the low-temperature gas discharge port, the low-temperature filling port and the low-temperature gas discharge port pass through the calibration cabin to the outside of the cabin, the low-temperature filling port is used for filling the low-temperature liquid, and the low-temperature gas discharge port is used for discharging the low-temperature storage tank to avoid overpressure; the lower surface of the low-temperature storage tank is the blackbody wall surface, which is used as a blackbody radiation source; the calibration cabin is provided with the cabin gas discharge port and the cabin gas inlet, which are used for cabin ventilation and vacuumization.

[0008] Further comprising a wall temperature sensor, a red-infrared light material and a vacuum cabin, the wall temperature sensor is arranged on the outer surface of the blackbody wall surface, the red-infrared light material is arranged below the blackbody wall surface, and the vacuum cabin is arranged between the red-infrared light material and the blackbody wall surface, which is used to avoid the lowest temperature affected by frosting or convection heat exchange of the blackbody wall surface.

[0009] The flexible adjustable device is arranged on the calibration cabin and is used to drive the equipment mounting positioning seat (5) to move and adjust the distance between the infrared equipment to be calibrated and the blackbody wall surface according to the focal length requirement of the infrared equipment to be calibrated, so that the low-temperature field of view meets the calibration requirement.

[0010] The low-temperature liquid is liquid methane, liquid oxygen, liquid nitrogen, liquid hydrogen or liquid helium.

[0011] The calibration cabin is filled with a gas corresponding to the low-temperature liquid. If the low-temperature liquid is liquid methane or liquid oxygen, the calibration cabin is filled with dry air or nitrogen; if the low-temperature liquid is liquid nitrogen, the calibration cabin is filled with nitrogen; and if the low-temperature liquid is liquid hydrogen or liquid helium, the calibration cabin is filled with helium.

[0012] The inner wall of the calibration cabin is blackened and frosted.

[0013] The cabin-penetrating electrical connector is further included, and the infrared equipment to be calibrated is connected with and controlled outside the cabin through the cabin-penetrating electrical connector.

[0014] An ultra-low-temperature blackbody furnace calibration method, which adopts the above ultra-low-temperature blackbody furnace for calibration and specifically includes the following steps:

[0015] (1) The type of the low-temperature liquid to be filled in the low-temperature storage tank is determined according to the requirement of the infrared equipment to be calibrated;

[0016] (2) The infrared equipment to be calibrated is mounted on the equipment mounting positioning seat, and the equipment mounting positioning seat is moved to adjust the distance between the infrared equipment and the blackbody wall surface;

[0017] (3) The calibration cabin is filled with gas through the cabin gas inlet and the cabin gas outlet to realize the replacement of the calibration cabin; if the infrared equipment to be calibrated is applied to a vacuum environment, the calibration cabin is evacuated to a pressure close to vacuum;

[0018] (4) The low-temperature storage tank is replaced with the corresponding gas, and the low-temperature liquid is filled in through the low-temperature filling port;

[0019] (5) During the filling of the low-temperature liquid, the wall temperature sensor measures the wall surface temperature in real time to output a blackbody radiation source with different low-temperature temperatures changing with time; after thermal equilibrium is reached, a low-temperature blackbody serving as a fixed-point temperature surface radiation source is obtained, and the calibration is completed.

[0020] In the step (4), after the gas replacement is completed, the calibration cabin is placed horizontally, and the blackbody wall surface serves as a side wall surface; then the low-temperature liquid is filled in to obtain a stepped temperature linear radiation source, and the calibration is completed.

[0021] In the step (2), the included angle between the equipment mounting positioning seat and the horizontal line is adjusted according to the requirement to realize the calibration of different areas of the infrared equipment focal plane.

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

[0023] (1) The ultra-low temperature blackbody of the present invention can provide surface radiation source and line radiation source according to calibration needs, and has the advantages of multi-functionality and ease of use; in the process of gradually reaching thermal equilibrium, it can output blackbody radiation source with different low temperature as time changes; the line radiation source can simultaneously provide standard blackbody radiation at different temperatures.

[0024] (2) In the embodiments of the present invention, common low-temperature liquids are preferably used as working fluids and high-precision wall temperature sensors are used as reference temperatures, which reduces complex temperature control links and makes the structure relatively simple.

[0025] (3) In the preferred embodiment of the present invention, the standard usage of the ultra-low temperature blackbody is proposed in combination with the usage requirements of the ultra-low temperature blackbody. The distance and angle between the infrared device and the blackbody wall can be adjusted by the equipment installation positioning device. Frosting or convective heat transfer can be avoided by gas replacement or vacuuming. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the ultra-low temperature blackbody furnace of the present invention as a surface radiation source for a fixed temperature.

[0027] Figure 2 This is a schematic diagram of the ultra-low temperature blackbody furnace of the present invention as a linear radiation source with stepped temperatures. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0029] like Figure 1 The diagram shows the schematic of an ultra-low temperature blackbody furnace that provides a fixed-point temperature surface radiation source, including a low-temperature filling port 1, a low-temperature venting port 2, a chamber venting port 3, a flexible adjustable device 4, an equipment mounting and positioning seat 5, a through-chamber electrical connector 7, a chamber air inlet 8, a low-temperature storage tank 9, a low-temperature liquid 10, a wall temperature sensor 11, an infrared-transmitting material 12, a vacuum chamber 13, a blackbody wall 14, and a calibration chamber 15. The cryogenic filling port 1, cryogenic venting port 2, cryogenic storage tank 9, and cryogenic liquid 10 constitute the cryogenic system, which provides a stable cryogenic source after the cryogenic liquid is added; the wall temperature sensor 11, infrared-transmitting material 12, vacuum chamber 13, and blackbody wall 14 constitute a cryogenic blackbody with accurate wall temperature measurement. The wall temperature sensor 11 can accurately measure the wall temperature to characterize the temperature of the blackbody; the chamber venting port 3, flexible adjustable device 4, equipment mounting positioning seat 5, through-chamber electrical connector 7, chamber air inlet 8, and calibration chamber 15 constitute the calibration auxiliary equipment, which can provide the infrared equipment 6 to be calibrated with an installation position that can be adjusted according to the focal length, a specific gas environment, or a vacuum environment.

[0030] The low-temperature storage tank 9 and the equipment mounting positioning seat 5 are arranged in the calibration cabin 15, the infrared equipment 6 to be calibrated is fixed through the equipment mounting positioning seat 5, the connection and control with the outside of the cabin are realized through the cabin-penetrating electric connector 7, the low-temperature filling port 1 and the low-temperature exhaust port 2 are arranged on the low-temperature storage tank 9, and the low-temperature filling port 1 and the low-temperature exhaust port 2 are connected with the outside of the cabin through the calibration cabin 15; the low-temperature filling port 1 is used for filling the low-temperature liquid 10, and the low-temperature exhaust port 2 is used for exhausting the low-temperature storage tank 9 to avoid overpressure of the low-temperature storage tank 9; the lower surface of the low-temperature storage tank 9 is a black body wall 14, which is used as a black body radiation source, a plurality of wall temperature sensors 11 are arranged on the black body wall 14, and an infrared light-transmitting material 12 is arranged below the black body wall 14; the vacuum cabin 13 is arranged between the infrared light-transmitting material 12 and the black body wall 14; the cabin exhaust port 3 and the cabin air inlet 8 are arranged on the calibration cabin 15, and are used for cabin ventilation and vacuumization; the flexible adjustable device 4 is arranged on the calibration cabin 15, and is used for moving the equipment mounting positioning seat 5 according to the focal length requirement of the infrared equipment, adjusting the distance between the infrared equipment and the black body wall, and making the low-temperature field of view meet the calibration requirement.

[0031] The low-temperature liquid commonly used as a low-temperature working medium, such as liquid methane, liquid oxygen, liquid nitrogen, liquid hydrogen, liquid helium and the like, is filled into the low-temperature storage tank 9, the black body wall 14 of the low-temperature storage tank 9 is cooled to a target temperature by using the low-temperature liquid, and the black body wall 14 can be used as a standard radiation source at the target temperature. By changing the storage state of the low-temperature liquid in the low-temperature storage tank 9, a fixed-point temperature surface radiation source and a stepped-temperature linear radiation source can be provided.

[0032] The specific use of the fixed-point temperature surface radiation source super-low-temperature black body for infrared equipment calibration is as follows:

[0033] (1) According to the requirement of the infrared equipment 6 to be calibrated, the type of the low-temperature liquid 10 filled into the low-temperature storage tank 9 is determined, such as liquid nitrogen (corresponding to a liquid temperature of about 77K under the sea level environment pressure), and the peripheral related filling equipment is prepared in advance;

[0034] (2) The infrared equipment 6 to be calibrated is installed on the equipment mounting positioning seat 5, and the connection and control between the infrared equipment 6 to be calibrated and the outside of the cabin are realized through the cabin-penetrating electric connector 7; the flexible adjustable device 4 is arranged on the calibration cabin, and is used for moving the equipment mounting positioning seat 5 according to the focal length requirement of the infrared equipment, adjusting the distance between the infrared equipment and the black body wall, and making the low-temperature field of view meet the calibration requirement;

[0035] (3), to avoid the black body wall 14 frost or convective heat transfer influence the minimum temperature of the wall, can be set to red infrared material 12 and vacuum chamber 13, and adopt the corresponding gas (liquid methane, liquid oxygen can be used dry air or nitrogen, liquid nitrogen with nitrogen, liquid hydrogen and liquid helium with helium), through the cabin inlet 8 and cabin gas outlet 3 to the calibration chamber 15 for charging and discharging, to achieve the replacement of the calibration chamber; for the infrared equipment used in vacuum environment, the calibration chamber 15 can be directly evacuated to near vacuum pressure;

[0036] (4), using the corresponding gas to complete the replacement of the low temperature storage tank 9, filling the low temperature liquid 10 (such as liquid nitrogen) from the low temperature filling port 1, and the low temperature gas outlet 2 is used for the exhaust of the low temperature storage tank 9 to avoid overpressure of the low temperature storage tank 9;

[0037] (5), in order to avoid the influence of the calibration of the wall reflection clutter in the calibration chamber 15, the inner wall of the calibration chamber 15 is blackened and frosted; during the slow filling process of the low temperature liquid, the wall temperature sensor 11 measures the wall temperature in real time, and due to the heat conduction effect, the temperature of the black body wall 14 gradually decreases, and the low temperature storage tank 9 and the low temperature liquid 10 gradually reach thermal equilibrium, which can output the black body radiation source of different low temperature temperatures changing with time; after reaching thermal equilibrium, it can be used as a standard low temperature black body of fixed point temperature.

[0038] When the super low temperature black body needs to provide a stepped temperature linear radiation source, the calibration chamber 15 is placed horizontally, as shown in Figure 2 The specific operation and requirement of calibration are the same as those of the fixed point temperature surface radiation source, except that the temperature of the surface of the black body wall 14 will show a stepped distribution of high temperature on the upper layer and low temperature on the lower layer when the low temperature liquid is filled in different amounts, which can be used as a linear radiation source, and the temperature of the wall temperature sensor 11 is used as a standard temperature to provide a standard black body radiation at different temperatures by interpolation method. According to the need, the angle between the equipment installation positioning seat 5 and the horizontal line can be adjusted to realize the calibration of different areas of the focal plane of the infrared equipment.

[0039] The above is only the best specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0040] The contents not described in detail in the specification of the present application belong to the known technology of the person skilled in the art.

Claims

1. An ultra-low temperature blackbody furnace, characterized by: The low-temperature filling port (1), the low-temperature gas outlet (2), the cabin gas outlet (3), the equipment mounting positioning seat (5), the cabin air inlet (8), the low-temperature storage tank (9), the low-temperature liquid (10), the black body wall (14) and the calibration cabin (15) are included, wherein the low-temperature storage tank (9) and the equipment mounting positioning seat (5) are arranged in the calibration cabin (15), the infrared equipment (6) to be calibrated is fixed through the equipment mounting positioning seat (5) and is electrically connected with the outside of the cabin; The low-temperature filling port (1) and the low-temperature gas outlet (2) are arranged on the low-temperature storage tank (9) and pass through the calibration cabin (15) to the outside of the cabin, the low-temperature filling port (1) is used for filling the low-temperature liquid (10), and the low-temperature gas outlet (2) is used for exhausting the low-temperature storage tank (9) to avoid overpressure; the lower surface of the low-temperature storage tank (9) is the black body wall (14) and is used as a black body radiation source; the calibration cabin (15) is provided with the cabin gas outlet (3) and the cabin air inlet (8) and is used for cabin ventilation and vacuumizing.

2. An ultra-low temperature blackbody furnace as claimed in claim 1, characterized in that: The wall temperature sensor (11), the infrared light permeable material (12) and the vacuum cabin (13) are further included, the wall temperature sensor (11) is arranged on the outer surface of the black body wall (14), the infrared light permeable material (12) is arranged below the black body wall (14), the vacuum cabin (13) is arranged between the infrared light permeable material (12) and the black body wall (14) and is used for avoiding frost formation of the black body wall (14) or affecting the minimum temperature of the black body wall (14) due to convection heat exchange.

3. An ultra-low temperature blackbody furnace as defined in claim 1, characterized in that: The flexible adjustable device (4) is further included and is arranged on the calibration cabin (15) and is used for moving the equipment mounting positioning seat (5) according to the focal length requirement of the infrared equipment (6) to be calibrated, adjusting the distance between the infrared equipment (6) to be calibrated and the black body wall (14) and making the low-temperature field of view meet the calibration requirement.

4. The ultra-low temperature blackbody furnace of claim 1, wherein: The low-temperature liquid (10) is liquid methane, liquid oxygen, liquid nitrogen, liquid hydrogen or liquid helium.

5. An ultra-low temperature blackbody furnace as claimed in claim 4, characterized in that: The calibration cabin (15) is filled with a gas corresponding to the low-temperature liquid (10), if the low-temperature liquid (10) is liquid methane or liquid oxygen, the calibration cabin (15) is filled with dry air or nitrogen, if the low-temperature liquid (10) is liquid nitrogen, the calibration cabin (15) is filled with nitrogen, and if the low-temperature liquid (10) is liquid hydrogen or liquid helium, the calibration cabin (15) is filled with helium.

6. An ultra-low temperature blackbody furnace as defined in claim 1, characterized in that: The inner wall of the calibration cabin (15) is blackened and ground.

7. An ultra-low temperature blackbody furnace as defined in claim 1, characterized by: The cabin-penetrating electric connector (7) is further included, and the infrared equipment (6) to be calibrated is connected with the outside of the cabin and controlled through the cabin-penetrating electric connector (7).

8. A calibration method for an ultra-low temperature blackbody furnace, characterized in that: The infrared equipment (6) to be calibrated is calibrated by using the super-low-temperature black body furnace of any one of claims 1-7, and the calibration specifically includes the following steps: (1) determining the type of the low-temperature liquid (10) filled in the low-temperature storage tank (9) according to the requirement of the infrared equipment (6) to be calibrated; (2) installing the infrared equipment (6) to be calibrated on the equipment mounting positioning seat (5), moving the equipment mounting positioning seat (5) and adjusting the distance between the infrared equipment and the black body wall; (3), the calibration chamber (15) is filled and discharged through the cabin air inlet (8) and the cabin air outlet (3), so as to realize the replacement of the calibration chamber (15); if the infrared device (6) to be calibrated is applied to a vacuum environment, the calibration chamber (15) is evacuated to a pressure close to vacuum; (4), the low-temperature tank (9) is replaced by using corresponding gas, and the low-temperature liquid (10) is filled from the low-temperature filling port (1); (5), during the filling of the low-temperature liquid (10), the wall temperature sensor (11) measures the wall temperature in real time, and outputs a blackbody radiation source with different low-temperature temperatures changing with time; after thermal equilibrium is reached, a low-temperature blackbody serving as a fixed-point temperature surface radiation source is obtained, and the calibration is completed.

9. The method of claim 8, wherein: In the step (4), after the gas replacement is completed, the calibration chamber (15) is placed transversely, and the blackbody wall (14) serves as a side wall; then the low-temperature liquid (10) is filled, a stepped temperature linear radiation source is obtained, and the calibration is completed.

10. The method of claim 8, wherein: In the step (2), the angle between the device mounting positioning seat (5) and the horizontal line is adjusted as required, so as to realize the calibration of different areas of the focal plane of the infrared device.

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