CN105043558A - Shielding method and apparatus for infrared radiation measurement of high-reflection surface - Google Patents

Abstract

The invention discloses a shielding method and device for high-back infrared radiation measurement, which can effectively ensure the measurement accuracy. The shielding method includes the selection of measurement orientation and measurement equipment, setting the size of the radiation shielding area, selecting and assembling suitable The shielding device, the installation of an infrared radiation measuring instrument and radiation measurement, and the correction of the influence of the shielding device's own radiation on the measurement results, etc. The invention adopts an open radiation shielding device, which can eliminate the influence of environmental radiation on radiation measurement, greatly increase the proportion of the high-back self-infrared radiation in the total radiation received by the infrared detector, and improve the measurement accuracy of the high-back self-radiation.

Description

A shielding method and device for measuring infrared radiation on a high-reflective surface

technical field

The invention relates to the technical field of infrared radiation measurement on object surfaces, in particular to a shielding method and device for infrared radiation measurement on high-reflective surfaces.

Background technique

When measuring infrared radiation, the infrared radiation of the surrounding environment is a non-negligible source of interference. Non-blackbody measured objects always have different reflective abilities, and the ambient infrared radiation can enter the infrared radiation measuring instrument after being reflected by the measured object. Only a part of the total radiation received by the infrared radiation measuring instrument comes from the self-radiation of the measured object, and the interference of environmental radiation on the infrared radiation measurement of the high-reverse surface (smooth object surface with high infrared reflectivity) is particularly serious. When the infrared reflectance of the measured object is high and the temperature is close to or lower than the surrounding environment, the ambient radiation can be reflected into the infrared radiation measuring instrument on the high side, and only a part or even a small part of the total radiation received by the infrared radiation measuring instrument may come from self-radiation. Common high back surfaces include glass, ceramics, metal, painted surfaces, smooth plastic surfaces, etc. For a long time, the infrared radiation measurement of the high negative surface has been considered to be inaccurate, and the infrared radiation measurement of the high negative surface itself has always been a blind spot in the infrared radiation measurement.

In order to reduce the reflection interference of ambient infrared radiation on the measured object, two solutions have been adopted. The first is to cool and evacuate the local environment around the infrared measurement platform with liquid nitrogen as a whole, so as to greatly reduce the radiation intensity of the environment itself. The high-precision infrared standard measuring equipment of the German National Metrology Institute and the vacuum infrared temperature standard equipment (VRTSF) of the China Institute of Metrology, both adopt the overall liquid nitrogen cooling and vacuum environment design, representing the cutting-edge level of high-precision infrared radiation measurement. The overall liquid nitrogen refrigeration and vacuum design of the test platform is extremely expensive, has poor versatility, and is difficult to apply to outdoor environments. Most experimental platforms cannot adopt this solution. The second solution is to equate the ambient thermal radiation to a black body uniform radiation, and eliminate the reflected ambient radiation through a mathematical correction model. The actual environment contains a variety of non-uniform environmental radiation. This method cannot measure the radiation distribution of objects, and can only be applied to single-point measurement with large errors.

A typical example of the reflection interference of ambient radiation on a high surface is the infrared imaging temperature measurement of a high surface. Due to the high reflectivity and low emissivity of the high back surface, when the surface temperature is lower than or close to the ambient temperature, only a small part of the infrared radiation received by the infrared thermal imaging camera measured on the high back side is the thermal radiation of the surface itself. The high anti-face has always been regarded as a blind spot in infrared imaging temperature measurement. At present, the infrared imaging temperature measurement of the high back surface is mainly used to form a local diffuse gray surface on the high back surface by means of surface coating, adhesive strips and other means. The infrared thermal imaging camera measures the temperature of the diffuse gray surface to reflect the temperature here. Coatings or glue strips will affect the performance of the high back surface and the original temperature distribution field, and only a few points of interest can be measured. Some high-reflective surfaces (such as optical glass, etc.) are limited by performance requirements, and it is difficult to cover the surface with coatings or adhesive strips. Direct and high-precision measurement of the self-infrared radiation intensity of the high-back surface is an urgent problem that needs to be solved in the temperature measurement of power inspection, optical components and smooth object surfaces.

Contents of the invention

The present invention overcomes the shortcomings in the prior art, and provides a shielding method for infrared radiation measurement on the surface of an object, which is low in cost, strong in versatility, easy to use, and can effectively ensure measurement accuracy. At the same time, the present invention also provides a A shielding device for the method.

In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

A shielding method for high-reflective infrared radiation measurement, comprising the following steps:

Step 1. Based on the appearance of the high surface and the actual measurement environment, give a suitable measurement orientation, that is, the orientation and distance of the infrared radiation measuring instrument relative to the high surface; evaluate its own infrared radiation intensity according to the emissivity and temperature of the high surface, and select A suitable infrared radiation measuring instrument ensures that the self-radiation intensity of the high back is within the calibration range of the measuring instrument;

Step 2. According to the external dimensions and measurement orientation of the high back surface, give the shape and size of the required radiation shielding area; the size of the radiation shielding area should ensure that the ambient infrared radiation will not enter the infrared radiation measuring instrument through mirror reflection on the high back surface ;

Step 3, splicing the shielding device according to the shape and size of the shielding area; the shielding device includes a base, and a cold plate vertically arranged on the base; the cold plate encloses a measurement area; the cold plate has a cavity for containing liquid nitrogen The cavity is provided with a liquid nitrogen injection port and a pressure relief port; the cold surface is made of blackened metal material with high thermal conductivity, and the remaining surface of the cold plate is provided with an insulation layer; the cold surface has a high Infrared radiation rate and infrared radiation absorptivity can inhibit the ambient radiation from entering the infrared radiation measuring instrument through the secondary reflection of the cold surface and the high negative surface;

Step 4. According to the specific infrared radiation measurement requirements, evaluate the measurement time, and select the liquid nitrogen and gas injection method of the cold plate; if the measurement time is long: choose the continuous air injection method to ensure that there is continuous gas blowing to the cold surface to prevent low-temperature cooling. The water vapor in the air caused by the cold surface condenses into an ice layer; the liquid nitrogen injection method also adopts a continuous injection method to prevent large temperature changes on the cold surface; if the measurement time is short: use a one-time liquid nitrogen injection method and use liquid nitrogen to evaporate Nitrogen is used as the anti-frost gas on the cold surface; since it takes a period of time for the cold surface to turn from frost to ice, in some short-term measurements, the anti-frost gas may not be used;

Step 5, according to the designed measurement orientation, install an infrared radiation measuring instrument to measure the infrared radiation distribution on the high back surface; the radiation received by the infrared radiation measuring instrument is mainly composed of two parts: the high back surface's own infrared radiation and the cold surface's reflected radiation on its surface; In general, since the temperature of the cold side is close to the temperature of liquid nitrogen, the radiation intensity of the common high-side is about 100 times higher than that of the cold side. When the high back surface fills the field of view of the measuring instrument, the infrared radiation received by the infrared radiation measuring instrument can be regarded as the infrared radiation of the high back surface itself;

Step 6, when measuring high-precision infrared radiation, it is necessary to correct the influence of infrared radiation on the cold surface on the measurement. According to the specific shape and orientation of the high surface and the shielding device, the reflected radiation distribution of the cold surface on the high surface is given by calculating radiology. In the radiation distribution image, the reflected radiation of the cold surface on the high negative surface is deducted to further improve the radiation measurement accuracy of the high negative surface; since the cavity containing liquid nitrogen is made of metal with high thermal conductivity, the temperature distribution of the cold surface does not change much, and the numerical calculation can take The cold surface temperature is set to a fixed value.

A device for realizing the above-mentioned shielding method, which includes a base, and a cold plate vertically arranged on the base; the cold plate encloses a measurement area; the cold plate has a cavity for containing liquid nitrogen, the The cavity is provided with a liquid nitrogen injection port and a pressure relief port; the surface of the cold plate adjacent to the measurement area is called the cold surface, and the cold surface is made of a metal material with high thermal conductivity that has been blackened, and the remaining surfaces of the cold plate are An insulation layer is provided.

Preferably, a cavity containing gas is provided in the base, and a gas injection port is provided on the cavity; a slit-shaped gas port extending along the inner edge of the cold plate is provided on the base for feeding the cold plate to the cold plate. Spray anti-frost gas on the surface.

Preferably, the base is spliced by a plurality of base unit blocks, and each base unit block has a gas-accommodating cavity and communicates with each other.

Preferably, the cold plate is spliced by a plurality of cold plate unit blocks, and each cold plate unit block has a cavity for containing liquid nitrogen, and the cavity is provided with a liquid nitrogen injection port and a pressure relief port.

Preferably, the cold plate and the base are detachably connected.

Preferably, at least two standpipes are vertically arranged on the surface of the cold plate away from the measurement area, and pluggable insertion rods are inserted into the riser pipes, and blind holes corresponding to the riser pipes are provided on the base; the insertion rods pass through Through the standpipe and into the blind hole of the base, the detachable connection between the cold plate and the base is realized.

Preferably, the pressure relief port of the cavity on the cold plate is connected to the gas injection port of the cavity on the base through a pipe.

Compared with the prior art, the present invention adopts an open shielding environment radiation design, which can greatly increase the proportion of the infrared radiation of the high back surface in the total radiation received by the infrared radiation measuring instrument, and improve the radiation measurement accuracy of the high back surface. Compared with the overall environment liquid nitrogen refrigeration and vacuum technology widely used in the existing high-precision infrared measurement, the present invention has the following advantages:

(1) The cold surface with low temperature and high emissivity not only weakens its own infrared radiation, but also eliminates the influence of environmental radiation entering the infrared radiation measuring instrument through the secondary reflection of the cold surface and high negative surface. Combined with the anti-frost design, an open design that suppresses ambient infrared radiation is realized.

(2) Compared with the current overall environment liquid nitrogen refrigeration and vacuuming technology in the field of suppressing environmental infrared radiation, the present invention adopts an open non-vacuum design, which greatly reduces the cost and technical difficulty of shielding environmental infrared radiation, and reduces various infrared radiation. Threshold for infrared radiation shielding in measurement experiments.

(3) The modular splicing design adopted by the shielding device improves the versatility and portability of the product, and improves the feasibility of applying the shielding device to various infrared measurement places.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a schematic structural view of the present invention in use.

FIG. 2 is an enlarged schematic view of the base unit block in FIG. 1 .

FIG. 3 is an enlarged schematic view of the cold plate unit block in FIG. 1 .

FIG. 4 is a schematic cross-sectional view of FIG. 3 .

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A shielding method for high-reflective infrared radiation measurement, comprising the following steps:

Step 1. Based on the appearance of the high surface and the actual measurement environment, give a suitable measurement orientation, that is, the orientation and distance of the infrared radiation measuring instrument relative to the high surface; evaluate its own infrared radiation intensity according to the emissivity and temperature of the high surface, and select A suitable infrared radiation measuring instrument ensures that the self-radiation intensity of the high back is within the calibration range of the measuring instrument;

Step 2. According to the external dimensions and measurement orientation of the high back surface, give the shape and size of the required radiation shielding area; the size of the radiation shielding area should ensure that the ambient infrared radiation will not enter the infrared radiation measuring instrument through mirror reflection on the high back surface ;

Step 3, splicing the shielding device according to the shape and size of the shielding area; the shielding device includes a base, and a cold plate vertically arranged on the base; the cold plate encloses a measurement area; the cold plate has a cavity for containing liquid nitrogen The cavity is provided with a liquid nitrogen injection port and a pressure relief port; the cold surface is made of blackened metal material with high thermal conductivity, and the remaining surface of the cold plate is provided with an insulation layer; the cold surface has a high Infrared radiation rate and infrared radiation absorptivity can inhibit the ambient radiation from entering the infrared radiation measuring instrument through the secondary reflection of the cold surface and the high negative surface;

Step 4. According to the specific infrared radiation measurement requirements, evaluate the measurement time, and select the liquid nitrogen and gas injection method of the cold plate; if the measurement time is long: choose the continuous air injection method to ensure that there is continuous gas blowing to the cold surface to prevent low-temperature cooling. The water vapor in the air caused by the cold surface condenses into an ice layer; the liquid nitrogen injection method also adopts a continuous injection method to prevent large temperature changes on the cold surface; if the measurement time is short: use a one-time liquid nitrogen injection method and use liquid nitrogen to evaporate Nitrogen is used as the anti-frost gas on the cold surface; since it takes a period of time for the cold surface to turn from frost to ice, in some short-term measurements, the anti-frost gas may not be used;

Step 5, according to the designed measurement orientation, install an infrared radiation measuring instrument to measure the infrared radiation distribution on the high back surface; the radiation received by the infrared radiation measuring instrument is mainly composed of two parts: the high back surface's own infrared radiation and the cold surface's reflected radiation on its surface; In general, since the temperature of the cold side is close to the temperature of liquid nitrogen, the radiation intensity of the common high-side is about 100 times higher than that of the cold side. When the high back surface fills the field of view of the measuring instrument, the infrared radiation received by the infrared radiation measuring instrument can be regarded as the infrared radiation of the high back surface itself;

Step 6, when measuring high-precision infrared radiation, it is necessary to correct the influence of infrared radiation on the cold surface on the measurement. According to the specific shape and orientation of the high surface and the shielding device, the reflected radiation distribution of the cold surface on the high surface is given by calculating radiology. In the radiation distribution image, the reflected radiation of the cold surface on the high negative surface is deducted to further improve the radiation measurement accuracy of the high negative surface; since the cavity containing liquid nitrogen is made of metal with high thermal conductivity, the temperature distribution of the cold surface does not change much, and the numerical calculation can take The cold surface temperature is set to a fixed value.

Figures 1-4 show the shielding device used to implement the above shielding method. In the figure, 10 is an infrared imaging thermometer, and 20 is a measured object with a high reverse surface. The shielding device of the present invention comprises a base 1, and a cold plate 2 vertically arranged on the base 1; the cold plate of the present embodiment is made of three flat plates, and the three flat plates encircle the measurement area; obviously, the cold plate 2 can also be For other suitable shapes, the shape of the cold plate 2 can be reasonably selected according to the measurement needs; the cold plate 2 has a cavity for containing liquid nitrogen, and the cavity is provided with a liquid nitrogen injection port 21 and a pressure relief port 22; The surface 23 of the upper cavity of the cold plate 2 adjacent to the measurement area is called the cold surface, and the cold surface is made of a metal material with high thermal conductivity through blackening treatment, and the remaining surface 24 of the cold plate 2 is provided with an insulating layer.

Wherein, the base 1 is provided with a cavity for containing gas, and the cavity is provided with a gas injection port 11; the base 1 is provided with a slit-shaped gas port 12 extending along the inner edge of the cold plate 2 for supplying air to the cold plate 2. Anti-frost gas is sprayed on the surface 23 of the plate 2 adjacent to the measurement area, and the anti-frost gas can be oxygen or nitrogen.

As a further improvement, the base 1 is spliced by a plurality of base unit blocks, and each base unit block has a cavity for containing gas and communicates with each other. The cold plate 2 is spliced by a plurality of cold plate unit blocks, and each cold plate unit block has a cavity for containing liquid nitrogen, and the cavity is provided with a liquid nitrogen injection port 21 and a pressure relief port 22 . Eight cold plate unit blocks are preferably used in this embodiment.

Wherein, two standpipes 3 are vertically arranged on the surface of the cold plate 2 away from the measurement area, and a pluggable insertion rod 4 is inserted into the standpipe 3, and a blind hole 13 corresponding to the standpipe 3 is arranged on the base 1; The insertion rod 4 passes through the standpipe 3 and extends into the blind hole 13 of the base 1 to realize the detachable connection between the cold plate 2 and the base 1 . Obviously, it can also be a commonly used detachable connection form such as snap connection.

As a further improvement, the pressure relief port 22 of the upper cavity of the cold plate 2 is connected to the gas injection port 11 of the upper cavity of the base 1 through a pipeline (not shown in the figure), so as to realize further utilization of liquid nitrogen after gasification.

The assembly process is as follows:

Step 1: According to the actual requirements of infrared radiation measurement, calculate the space area to be shielded, and build the base of the shielding device. Based on the shape of the base, the base unit blocks are assembled to realize the communication of the internal cavities of each base unit block, leaving a gas injection port. The high-pressure gas cylinder is connected to the main injection port of the base and injected with gas, and the slit-shaped gas ports of each base unit block can eject a layer of air flow close to the cold surface.

Step 2: According to the calculation of the radiation shielding area, assemble the insertion rods of the specified height on each base unit block. Based on the installed base and plunger, assemble the cold plate unit block. Each cold plate unit block has a cavity for containing liquid nitrogen, so that the cold surface is in a low temperature state. The cold surface has a high absorption rate of infrared radiation, and the back of the cold plate has a fixed structure, which can be integrated with the base through the insertion rod.

Step 3: After the cold plate assembly is completed, connect the liquid nitrogen injection ports of each cold plate unit block through the multi-way joint to lead out a total liquid nitrogen injection port. Use a multi-way joint to join the pressure relief ports of the cold plate unit blocks to lead out a general pressure relief port.

Step 4: Use a liquid nitrogen pump and a liquid nitrogen tank to inject liquid nitrogen into the cavity of each cold plate through the total liquid nitrogen injection port. The liquid nitrogen injection port of each cold plate unit block is equipped with a flow control valve, which is used to control the flow rate of liquid nitrogen flowing to each cold plate unit block. The cold surface of each cold plate unit block has different thermal environment boundaries, such as differences in wind speed, solar irradiance, air temperature, etc., and the volatilization speed of liquid nitrogen in each cold plate unit block will be different. By adjusting the liquid nitrogen injection flow rate of each cold plate unit block, the total amount of liquid nitrogen in the cavity of each cold plate unit block can be equalized, and the liquid nitrogen refrigeration of each cold plate unit block is basically in a steady state.

The cavity containing liquid nitrogen on the cold plate unit block is made of high thermal conductivity metal material, and the fluctuation and change of the amount of liquid nitrogen will cause small temperature fluctuations and temperature gradients on the cold surface. For most infrared radiation measurement platforms, the lower the temperature of the cold surface of the cold plate, the higher the infrared radiation absorption rate, and the better the radiation shielding effect. When the cold plate is in the low temperature state of liquid nitrogen refrigeration, the temperature fluctuation and gradient of the cold surface have little influence on the radiation shielding performance. Considering the high price of the liquid nitrogen pump and liquid nitrogen flow control valve, the liquid nitrogen injection method can be replaced by a self-pressurized liquid nitrogen tank: the liquid nitrogen output of the self-pressurized liquid nitrogen tank has a flow adjustment function, which can control the total injection port The liquid nitrogen flow rate. The difference in the thermal environment of each cold plate unit block is weak, and the volatilization rate of liquid nitrogen is not much different. In the actual environment, adjusting the total flow rate can ensure that the amount of liquid nitrogen in each cavity is generally in a stable state. When the volatilization rate of some cold plate unit blocks is slow , excess liquid nitrogen can flow out through the pressure relief port.

Step 5: After the liquid nitrogen injection device is started, the temperature of the cold surface is extremely low, and the water vapor in the surface air will condense into frost on the cold surface. After a period of time, as the amount of frosting increases, an ice layer gradually appears on the cold surface. The infrared radiation reflectivity of the ice layer is high, and a part of the ambient radiation will enter the infrared radiation measuring instrument after being reflected twice by the ice layer and the high back surface.

The cold surface is in direct contact with the outside air, and although the temperature of the cold surface is much lower than the air temperature, it is higher than the melting point temperature of nitrogen and oxygen. The slit-shaped air port of the base can inject nitrogen or oxygen air flow upwards to form an air knife, and the air knife impacts the cold surface and forms a protective gas layer with a certain thickness above the surface. The air layer can effectively inhibit the contact of water vapor with the low-temperature cold surface. Nitrogen and oxygen are symmetrical molecules, which do not cause changes in galvanic moments when they vibrate, and neither absorb nor emit infrared radiation. The low-temperature cold surface only has nitrogen and oxygen with extremely low melting points, which avoids the phenomenon of freezing on the cold surface. If the infrared measurement platform is in an open environment, only nitrogen or oxygen can be used as the protective gas; if the platform is located in an indoor closed environment, a mixed gas of nitrogen and oxygen is required, and the ratio of the two gases is similar to that in the air. The shielding device can be operated indoors for a long time.

In fact, except for some long-term infrared experiment platforms, many infrared radiation measurements take a very short time. Devices such as the air port on the base and the liquid nitrogen supply system are expensive and difficult to install. A simplified version of the shielding device can be used for infrared radiation measurements that take a short time. The shielding device can be simplified as without any pipeline, and the liquid nitrogen injection port is closed after filling with liquid nitrogen, and a pressure relief valve is installed at the pressure relief port for use. The other five surfaces of the cold plate are provided with insulation layers. After the cavity of the cold plate is filled with liquid nitrogen, the cold surface can be kept at a low temperature for a relatively long period of time. Due to the short measurement time, no ice layer will form on the cold side. Another simplified device is to directly connect the pressure relief port with the air injection port, and the nitrogen volatilized by the liquid nitrogen is used to flush the cold surface to suppress frosting on the cold surface.

Under normal temperature, when infrared radiation imaging measurement is performed on the high surface of various smooth objects such as ordinary glass, ceramic tiles, galvanized sheets, painted surfaces, and ordinary metal surfaces, the reflected radiation of the surrounding environment on the surface can reach several times the radiation intensity of the high surface itself , Infrared imaging can clearly see the reflection imaging of the ambient heat source on its surface. At present, the lower limit of temperature measurement and calibration of infrared thermal imaging cameras on the market can reach -60°C, which can accurately measure the radiation intensity of the normal temperature and high back surface with emissivity above 0.15. Most of the high backside radiation intensity is actually within the calibration range of the thermal imager, and its infrared radiation can be directly measured. The interference of reflected radiation from the environment on its surface greatly weakens the reliability of infrared radiation measurements of high-reflected surfaces. The present invention limits the shielding area of the ambient infrared radiation to the area that can enter the infrared radiation measuring instrument through quasi-mirror reflection on a high back surface, and uses a cold surface with low temperature and high emissivity to shield all infrared radiation that can enter the infrared radiation measuring instrument through mirror reflection , which greatly increases the proportion of the infrared radiation of the high negative surface in the total infrared radiation received by the infrared radiation measuring instrument, effectively improving the measurement accuracy of infrared radiation.

In the present invention, the design of an air knife with a certain thickness close to the cold surface is ejected from the slit-shaped air port, and the characteristics of nitrogen and oxygen with low melting point temperature are used to prevent water vapor from freezing on the cold surface. For most infrared radiation measurements, the distance between the measured object and the infrared radiation measuring instrument is relatively close, and the air infrared radiation in the measurement path is completely negligible. The vacuum design used in high-precision infrared measurement equipment has greatly increased the cost of the equipment. The equipment used in the present invention is relatively simple and easy to obtain, less difficult to design and process, lower in cost, and convenient in assembly due to modular design, and can be applied to precise measurement of various high-back infrared radiation indoors and outdoors.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (8)

1., for a screen method for high reverse side infrared radiation measurement, it is characterized in that comprising the following steps:

Step 1, based on high reverse side external form and actual measurement environment, provides suitable measurement orientation, i.e. the azimuth-range of the relatively high reverse side of infrared radiometer; According to emissivity and the temperature of high reverse side, assess himself infrared intensity, select suitable infrared radiometer, ensure that self radiation intensity of high reverse side is within the scope of the calibration of measuring instrument;

Step 2, according to physical dimension and the measurement orientation of high reverse side, provides shape and the size of required radiation-shielded areas; The size of radiation-shielded areas will ensure that the infrared radiation of environment can not enter infrared radiometer at high reverse side through mirror-reflection;

Step 3, according to shape and the size of shielding area, mosaic screen shielding apparatus; Shield assembly comprises base, and is vertically arranged at the cold drawing on base; Described cold drawing surrounds measurement zone; Described cold drawing has the cavity holding liquid nitrogen, this cavity is provided with liquid nitrogen inlet and pressure relief opening; Huyashi-chuuka (cold chinese-style noodles) adopts and makes through the metal material of the high thermal conductivity coefficient of blackening process, and the remaining surface of cold drawing is provided with heat-insulation layer; Huyashi-chuuka (cold chinese-style noodles) has higher infrared emittance and infrared radiation absorption rate, and environmental radiation can be suppressed to enter infrared radiometer through huyashi-chuuka (cold chinese-style noodles) and high reverse side secondary reflection;

Step 4, according to concrete infrared radiation measurement requirement, assessment Measuring Time, selects liquid nitrogen and the gas injection mode of cold drawing; If Measuring Time is long: select continuous air Injection mode, ensures lasting gas and blow to huyashi-chuuka (cold chinese-style noodles), prevent low temperature huyashi-chuuka (cold chinese-style noodles) from causing the water vapor condensation of air to become ice sheet; Liquid nitrogen injection mode also adopts continuous injection mode, prevents huyashi-chuuka (cold chinese-style noodles) from occurring larger temperature variation; If Measuring Time is shorter: select disposable liquid nitrogen injection mode, the nitrogen adopting liquid nitrogen to volatilize is as the antifrost gas of huyashi-chuuka (cold chinese-style noodles); Because huyashi-chuuka (cold chinese-style noodles) needs a period of time from frosting to ice sheet, when some is measured in short-term, antifrost gas can not be used;

Step 5, according to the measurement orientation of design, installation infrared radiation survey meter, measures the infrared radiation distribution of high reverse side; Primarily of self infrared radiation of high reverse side and huyashi-chuuka (cold chinese-style noodles), the reflected radiation two parts on its surface form in the radiation that infrared radiometer accepts; Generally, because coldface temperature is close to liquid nitrogen temperature, the radiation intensity of common high reverse side is about more than hundred times of huyashi-chuuka (cold chinese-style noodles); When high reverse side is full of measuring instrument visual field, the infrared radiation that infrared radiometer accepts can regard the infrared radiation of high reverse side self as;

Step 6, during high precision infrared radiation measurement, need to revise huyashi-chuuka (cold chinese-style noodles) infrared radiation to the impact of measuring, according to concrete shape and the orientation of high reverse side and shield assembly, provide huyashi-chuuka (cold chinese-style noodles) by calculating radiology to distribute in the reflected radiation of high reverse side, in radiation profiles image, deduct the reflected radiation of huyashi-chuuka (cold chinese-style noodles) at high reverse side, promote the actinometry precision of high reverse side further; Because the cavity holding liquid nitrogen adopts high thermal conductivity coefficient metal, the Temperature Distribution change of huyashi-chuuka (cold chinese-style noodles) is little, coldface temperature can be set to fixed value in numerical evaluation.

2. for realizing a device for screen method as claimed in claim 1, it is characterized in that: comprise base, and be vertically arranged at the cold drawing on base; Described cold drawing surrounds measurement zone; Described cold drawing has the cavity holding liquid nitrogen, this cavity is provided with liquid nitrogen inlet and pressure relief opening; The surface that described cold drawing closes on measurement zone is called huyashi-chuuka (cold chinese-style noodles), and huyashi-chuuka (cold chinese-style noodles) adopts and makes through the metal material of the high thermal conductivity coefficient of blackening process, and the remaining surface of cold drawing is provided with heat-insulation layer.

3. device according to claim 2, is characterized in that: arrange the cavity holding gas in described base, this cavity is arranged gas inject mouth; Described base is provided with the gas port of the slit-shaped extended along cold drawing inside edge, sprays antifrost gas for the huyashi-chuuka (cold chinese-style noodles) to cold drawing.

4. device according to claim 3, is characterized in that: described base is spliced by multiple base unit block, and each base unit block has the cavity of accommodation gas and is interconnected.

5. device according to claim 2, is characterized in that: described cold drawing is spliced by multiple cold drawing cell block, and each cold drawing cell block all has the cavity holding liquid nitrogen, and cavity is provided with liquid nitrogen inlet and pressure relief opening.

6. according to the arbitrary described device of claim 2-5, it is characterized in that: described cold drawing and base adopt and removably connect.

7. device according to claim 6, is characterized in that: described cold drawing at least vertically arranges two standpipes away from the surface of measurement zone, inserts pluggable inserted link in standpipe, and described base arranges the blind hole corresponding with standpipe; Described inserted link is through standpipe and stretch into the blind hole of base, realizes removably connecting of cold drawing and base.

8. the device according to claim 3 or 4, is characterized in that: the pressure relief opening of described cold drawing upper cavity is connected with the gas inject mouth of base upper cavity by pipeline.