JPH0514852B2 - - 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 the emissivity and temperature pattern 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 detects the difference in detected values between when radiant energy from a radiation source reflected from a measurement object is incident on a scanning radiation thermometer and when it is not, and the value related to the radiation source temperature. This is an apparatus for measuring the emissivity and temperature of an object, which calculates the emissivity based on the fact that a correction coefficient, which is a ratio, has a predetermined relationship with the emissivity of the object to be measured, and calculates the temperature from this emissivity.

(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 1 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 radiant energy reflected from 1 is incident on the scanning radiation thermometer 2; 4 is the scanning radiation thermometer 2;
2, a background radiation plate (wall) having an opening that emits the radiant energy of the radiation sources 31 and 32, and an opening that receives the radiant energy of the scanning radiation thermometer 2;
5 is a temperature detector such as a thermocouple or a resistance temperature detector for detecting the temperature of the background radiation plate 4; 6 is a scanning radiation thermometer 2, radiation sources 31 and 32, and an output signal of the temperature detector 5; This is a calculation means using a microcomputer, a personal computer, or an analog circuit.

In addition, the scanning radiation thermometer 2 will be described below with one axis (-
The explanation will be given for the scanning type (dimensional) scanning type, but the same applies to the surface scanning type, and the radiation sources 31 and 32 are 1
Alternatively, the background radiation plate 4 may be a normal wall surface.

The temperature of the measurement object 1 is T, the emissivity is ε, the reflectance is ρ, the temperature of the radiation sources 31 and 32 is Tr, the emissivity is εr,
Tw the temperature of the background radiation plate 4, scanning radiation thermometer 2
The output signal of is E(S), and the radiant energy of a black body at temperature T is E(T).

When the scanning radiation thermometer 2 scans the measurement object 1, a high output signal is obtained when radiant energy from the radiation sources 31 and 32 is incident, as shown in FIG.

The output signal when the radiation energy from the radiation sources 31 and 32 enters the scanning radiation thermometer 2 is expressed as E.
(S ₁ ), and the output signal when it is not incident is E(S ₂ ), the following equation holds true.

E(S ₁ )=εE(T)+αρεrE(Tr) +βρE(Tw) ...(1) E(S ₂ )=εE(T)+ρE(Tw) =εE(T)+αρE(Tw) +βρE(Tw) ...(2) Here, α is the ratio of the radiation energy from the radiation sources 31 and 32 reflected by the measurement object 1 and incident on the scanning radiation thermometer 2, and β is the ratio of the radiation energy from the background radiation plate 4 to the measurement object 1 and enters the scanning radiation thermometer 2, α+β=1.

In other words, the scanning radiation thermometer 2
2, the first term on the right side of equation (1) is the radiation energy from the measurement object 1 itself, and the second term is the radiation source 31,
32, the third term is the contribution of the radiant energy from the background radiation plate 4, and on the right side of equation (2) when the scanning radiation thermometer 2 does not see the radiation sources 31 and 32, the radiation source 31 , 32, and only the contribution from the background radiation plate 4.

When formulas (1) and (2) are subtracted, the following formula is obtained.

E(S ₁ ) − E(S ₂ ) = αρ {εrE(Tr) − E(Tw)} αρ = [E(S ₁ ) − E(S ₂ )] / [εrE(Tr) − E(Tw) ] ...(3) Here, let the left side be k, and the value of this left side k can be obtained by measurement from the right side.

On the other hand, it has been experimentally found that the relationship between k=αρ and emissivity ε is a linear relational expression as shown in the following equation.

ε=A-Bk=A-B(αρ)...(4) To illustrate this relationship, as shown in Figure 3,
The straight lines differ depending on the types of objects M ₁ and M ₂ . Coefficients A (A ₁ , A ₂ , ...), B (B ₁ , B ₂ , ...)
is determined in advance through experiments for each type of object to be measured.

Therefore, since ε+ρ=1, E(T)=E(S ₂ )−(1−ε)E(Tw)/ε ……(5) from equation (2), and this equation (5) By substituting the emissivity ε obtained from equation (4), the true temperature T of the measurement object 1 is found.

Note that in the above equation, if the temperature Tw of the background radiation plate 4 is sufficiently small, Tw can be omitted.

That is, before measurement, the emissivity εr of the radiation sources 31 and 32 and the coefficients A ₁ , A ₂ , ..., B ₁ , which correspond to the type of the measurement object 1 are stored in the storage means included in the calculation means 6.
B ₂ , . . . are stored in advance so that they can be selected and read out according to the type of the measurement object 1.

During measurement, the scanning radiation thermometer 2 scans the measurement object 1 and outputs an output signal Ei corresponding to each scanning position Xi.
is supplied to the calculation means 6. At this time, for example,
E ₂ and E ₅ are the output signals when _the radiation sources 31 _{and 32 are} scanned at scanning _positions X ₂ and Let the output signals be from the positions on both sides of the positions X ₂ and X ₅ that are reflected at 1. In addition, temperature signals of the radiation sources 31 and 32
The output signal of the temperature detector 5 which detects the temperature Tw of the background radiation plate 4 is also supplied to the calculation means 6.

The calculation means 6 performs calculations such as E ₂ −E ₁ +E ₃ /2 and E ₅ −E ₄ +E ₆ /2 to obtain the numerator of equation (3), and calculates Tr and Tw to obtain E(Tr). ，
E(Tw) and using εr, εrE(Tr)−E(Tw)
is calculated as the denominator of equation (3), and from equation (3) αρ=k
, and using these two values of k and A, B, (4)
Find the two emissivities ε from the formulas. The average value of these two emissivities ε is taken as the emissivity of the measurement object, and each point Xi
The temperature T at each point can be determined by substituting it into equation (5) together with the radiant energy detection signal Ei, and can be used as the output of the calculation means 6.

In this way, by using the radiation sources 31 and 32, the emissivity ε of the measurement object 1 can be determined, and the temperature 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, the three radiation sources 31, 32, 33 are provided at a predetermined angle to the scanning radiation thermometer 2 with respect to the normal to the measurement object 1, and the temperature controllers 71, 7
2 and 73, the temperature is controlled to a predetermined temperature Tr. In addition, the output of the calculation means 6 is
Displayed on display 74, analog recorder 75,
It is beginning to be recorded. Also, emissivity ε
is not the average value of radiation sources 31, 32, 33,
The measuring object 1 may be divided into three zones along the traveling direction, and the emissivity may be determined for each zone.

FIG. 5 shows another embodiment, in which the same reference numerals as in FIGS. 1 and 4 indicate the same components. In this example,
One radiation source 31 is configured to radiate radiant energy along the scanning line l of the scanning radiation thermometer 2 by moving in parallel or swinging, and the radiant energy from the radiation source 31 is radiated at approximately the same point. The emissivity ε of each point on the scanning line l is calculated based on the detected value of the scanning radiation thermometer 2 when the radiation is incident and when it is not, and the temperature T of each point is calculated from the emissivity ε of each point.
Continuous values are obtained. These calculations are performed by calculation means 6 having storage means. As a result, accurate temperature measurement can be performed even with respect to the distribution and fluctuation of the emissivity of the measurement object 1.

In addition, when the scanning radiation thermometer 2 is a surface (two-dimensional) scanning type, at least one radiation source 31 that emits radiant energy within the scanning area, or
Emissivity and temperature distribution can be obtained by similar calculations using a radiation source 31 that scans by emitting radiant energy into the scanning area.

(6) Effects of the invention The emissivity and temperature are measured using a scanning radiation thermometer by taking advantage of the predetermined relationship between the emissivity and the correction coefficient, so the configuration is simple. With this, it is possible to measure the correct temperature distribution with emissivity correction over a wide range of the measurement object. In addition, by changing the correction coefficient of the relational expression, it can be applied to various objects, and by scanning multiple radiation sources and radiation sources, it can be more accurate and
Can measure continuous emissivity and temperature distribution.

[Brief explanation of drawings]

1, 4, and 5 are configuration explanatory diagrams showing one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining operation, and FIG. 3 is a relationship diagram between emissivity and correction coefficient. be. 1...Measurement object, 2...Scanning radiation thermometer, 3
1, 32, 33...radiation source, 4...background radiation plate,
5...Temperature detector, 6...Calculating means.

Claims (1)

[Claims] 1. A scanning radiation thermometer that scans a measurement object to detect radiant energy from the measurement object, and at least a scanning radiation thermometer that radiates radiant energy to the measurement object within the scanning area of the scanning radiation thermometer. One emissivity εr, temperature
Tr radiation source and background radiation plate. a temperature detector that detects a temperature Tw, and a difference E( A correction coefficient that is the ratio of S1) - E (S2) and the difference εrE (Tr) - E (Tw) between the values related to the two radiant energies emitted by the radiation source and the background radiation plate obtained from a temperature detector etc. k is calculated, and this correction coefficient k and the emissivity ε of the measurement object have a linear relationship ε=A−Bk determined in advance by experiment.
Measuring the emissivity and temperature of an object, comprising: calculation means for determining the emissivity ε based on the fact that (A and B are constants) and calculating the temperature T of the object to be measured from this emissivity ε. Device. 2. Claim 1, characterized in that it is equipped with a calculation means for storing, selecting and calculating at least one set of coefficients of the linear relational expression between the emissivity and the correction coefficient for each type of measurement object. Apparatus for measuring the emissivity and temperature of the object described in Section 1. 3 Detection value when the radiant energy from the radiation source is reflected by the measurement object and enters the scanning radiation thermometer, and detection of radiant energy from near the reflection position where the radiant energy from the radiation source is reflected by the measurement object. 3. An apparatus for measuring the emissivity and temperature of an object according to claim 1 or 2, characterized in that the emissivity is calculated using the difference between the emissivity and the emissivity. 4. A radiation source is provided on the scanning line of the scanning radiation thermometer that vertically scans the measurement object, or at a predetermined angle with respect to the scanning radiation thermometer with respect to the normal to the measurement object. An apparatus for measuring emissivity and temperature of an object according to any one of claims 1 to 3. 5. Claims 1 to 4, characterized in that a plurality of the radiation sources that radiate radiant energy to the measurement object or a radiation source that scans and radiates radiant energy to the measurement object are used. A device for measuring emissivity and temperature of an object according to any one of the above. 6. The device for measuring the emissivity and temperature of an object according to any one of claims 1 to 5, characterized in that the radiation source includes a background radiation plate having an aperture that emits radiant energy. .