JPH0511252B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to an apparatus for measuring the emissivity and temperature of steel plates and the like using a scanning radiation thermometer.

(2) Prior art As disclosed in Japanese Patent Application Laid-open No. 57-161521, for example, the applicant has determined the emissivity of a measuring object from the change in the output of a radiation detector when the distance between the comparison hot plate and the measuring object is changed. We are proposing a method to find the .

However, this method requires a large device to drive the comparative heating plate, and also has problems such as the difficulty of measuring emissivity and temperature patterns over a wide range of the measurement object because of the single-point measurement. There is.

(3) Purpose of the Invention In view of the above points, the purpose of the present invention is to provide a device for measuring the emissivity and temperature of an object, which makes it possible to more easily measure the emissivity and temperature of the object over a wide range. It is to be.

(4) Summary of the Invention This invention provides a contribution factor which is the ratio of the difference between detected values when two radiant energies are incident on a scanning radiation thermometer through different apertures from a radiation source and when they are not. An apparatus for measuring the emissivity and temperature of an object, which calculates the emissivity of the object to be measured based on the predetermined relationship between the ratio of be.

(5) Embodiment of the Invention FIG. 1 is a configuration explanatory diagram showing an embodiment of the invention.

In the figure, 1 is a measurement object such as a steel plate that runs perpendicular to the paper surface, and 2 is a CCD or scanning mirror that scans the width direction of the measurement object perpendicularly to detect the radiant energy from the measurement object 1. The scanning radiation thermometers 31 and 32 are located on both sides of the scanning line of the scanning radiation thermometer 2, and emit radiant energy to the measurement object 1 in the scanning area of the scanning radiation thermometer 2. A radiation source 4 is provided so that the reflected radiation energy enters the scanning radiation thermometer 2;
The radiant energy of the radiation sources 31 and 32 is measured through the apertures 41 and 42 of different sizes.
5 is a temperature detector that detects the temperature of the background radiation plate 4; 6 is the output signal of the scanning radiation thermometer 2; the radiation sources 31, 32; It is a calculation means such as an analog circuit, a microcomputer, a personal computer, etc., which is supplied with an output signal and performs predetermined calculation processing.

Temperature of measurement object 1 is T, emissivity is ε, radiation source 3
Let Tr be the temperature of 1 and 32, εr be the emissivity, Ta be the temperature of the background radiation plate 4, Ei be the output signal of the scanning radiation thermometer 2, and let E(T) be the radiant energy equivalent to a black body.

When the scanning radiation thermometer 2 scans the measurement object 1, as shown in FIG.
E ₁ and E ₂ are obtained, and a low output signal E ₀ is obtained when there is no incidence, and the following equation holds true.

E ₀ = εE(T)+(1-ε)E(Ta)...(1) E ₁ =εE(T)+F ₁ (1-ε)εrE(Tr)+(1-F ₁ )
(1-ε)E(Ta)...(2) E ₂ =εE(T)+F ₂ (1-ε)εrE(Tr)+(1-F ₂ )
(1-ε)E(Ta)...(3) Here, F ₁ and F ₂ are the contributions of the radiant energy from the radiation sources 31 and 32 reflected from the measurement object 1 and incident on the scanning radiation thermometer. rate, for example F ₁ >
It is _F2 .

In other words, the first term on the right side of equation (1) is the radiant energy from the measurement object 1 itself, the second term is the radiant energy from the background radiation plate 4, and the second term on the right side of equations (2) and (3) is the radiation energy from the radiation source 3.
1 and 32, and the third term is the contribution from the background radiation plate 4.

By subtracting equation (1) from equation (2) and subtracting equation (1) from equation (3), the following equation is obtained.

E ₁ −E ₀ =F ₁ (1−ε)εrE(Tr)−F ₁ (1−ε)
E(Ta) E ₂ −E ₀ =F ₂ (1−ε)εrE(Tr)−F ₂ (1−ε)
E(Ta) Taking the ratio R, the following equation is obtained.

R=F ₁ /F ₂ (4) Further, by subtracting equations (2) and (3), the following equation is obtained.

E ₁ −E ₂ = (F ₁ −F ₂ ) (1−ε) {εrE(Tr)−E
(Ta)} From this, the emissivity ε is given by the following formula.

ε=1−(E ₁ −E ₂ )/[(F ₁ −F ₂ )・{εrE(Tr)
−E(Ta)}] …(5) Here, the relationship between D=F ₁ −F ₂ and R=F ₁ /F ₂ is
As shown in FIG. 3, it was experimentally found that D=f(R), which is a predetermined functional relationship. In other words, R
Since D can be determined from the equation (5) and other values on the right side of equation (5) can be determined by measurement, etc., the emissivity ε can be determined.

Then, from equation (1), E(T)={E ₀ − (1-ε)E(Ta)}/ε...(6), so in equation (6), By substituting the emissivity ε, etc., the true temperature of the measuring object 1 is determined.

In other words, before the measurement, the functional relationship D=f(R) between D=F ₁ -F ₂ and R=F ₁ /F ₂ obtained by measurement as shown in FIG. 3, and the radiation of the radiation sources 31 and 32. The rate εr, etc. are stored in the calculation means 6.

Next, during measurement, the scanning radiation thermometer 2 scans the measurement object 1 and supplies an output signal Ei corresponding to each measurement position Xi to the calculation means 6. At this time, the output signals when the radiation sources 31 and 32 reflect the measurement object 1 are E ₁ and E ₂ , and the output signals at other times are E ₀ .
Further, the output signal of the temperature detector 5 which detects the temperature signal Tr of the radiation sources 31 and 32 and the temperature signal Ta of the background radiation plate 4 is also supplied to the calculation means 6.

The calculation means is a signal E ₀ corresponding to equations (1), (2), and (3).
Find the ratio R in equation (4) from E ₁ and E ₂ , find D from this, and find E(Tr) and E(Ta) from the signals Tr and Ta.
Calculate and calculate the right side of equation (5) to find the emissivity ε. Furthermore, the temperature T of the measurement object 1 can be determined by calculating equation (6) using this emissivity ε.

In this way, the emissivity ε of the measurement object 1 can be determined from the contribution factors of the radiation sources 31 and 32, and the temperature T at each point can be determined. After determining the emissivity ε in advance, the apertures of the radiation sources 31 and 32 may be shuttered to perform continuous measurements.

FIG. 4 shows another embodiment, in which the same reference numerals as in FIG. 1 indicate the same components. In this example, one radiation source 3 is provided at a predetermined angle with the scanning radiation thermometer 2 with respect to the normal to the measurement object 1, and the background radiation plate 4 has apertures of different sizes. 41,
The radiation energy of one radiation source 3 is radiated to the measuring object 1 via 42 .

(6) Effects of the invention Utilizing the fact that the difference in contribution rates has a predetermined relationship with the ratio of contribution rates, emissivity and temperature are measured using a scanning radiation thermometer, making it easy to measure. With this configuration, it is possible to measure the correct emissivity-corrected temperature distribution over a wide range of the measurement object.

[Brief explanation of drawings]

1 and 4 are configuration explanatory diagrams showing one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation, and FIG.
The figure is a diagram showing the relationship between the difference in contribution rate and the ratio. 1...Measurement object, 2...Scanning radiation thermometer,
3, 31, 32...radiation source, 4...background radiation plate,
5...Temperature detector, 6...Calculating means.

Claims (1)

[Claims] 1. A scanning radiation thermometer that detects radiant energy from the measuring object by scanning the measuring object, and a scanning radiation thermometer that emits radiant energy through apertures of different sizes to the measuring object within the scanning area of this scanning radiation thermometer. and the first and second radiation sources when the radiation energy from the first and second radiation sources reflects off the measurement object and enters the scanning radiation thermometer with contribution factors F1 and F2, respectively. 2 detected values E1, E2, and the first and second
The ratio R of the difference between the detected values E0 when the radiation energy from the radiation source is not incident from the measurement object
= (E1 - E0) / (E2 - E0) = F1 / F2 is calculated, and the ratio of this contribution rate R = F1 / F2 and the difference in contribution rate D = (F1
-F2), find the difference D in contribution rates based on the relationship determined experimentally in advance, use this difference D in contribution rates to find the emissivity of the measurement object, and find the temperature of the measurement object from this emissivity. 1. An apparatus for measuring emissivity and temperature of an object, characterized in that it is equipped with calculation means.