JPH0462011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to a device for measuring the temperature of a translucent body such as glass or polymer film.

(2) Prior Art There is a method of measuring the temperature of a semitransparent material using a radiation thermometer whose measurement wavelength is limited to the absorption band of the material.

However, in this method, since the wavelength is limited, the sensitivity is poor and the lower limit temperature for measurement cannot be kept low. Furthermore, measurement is particularly difficult when there is no significant absorption band.

(3) Purpose of the Invention The purpose of the present invention is to provide a temperature measuring device that can measure the temperature of a semi-transparent body with high accuracy by using a mirror at the above points.

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

In the figure, 1 is a wall covering a semi-transparent body 2 such as glass or polymer film to be measured, 3 is a mirror provided on the back of the semi-transparent body 2, and 4 is a wall covering a semi-transparent body 2 such as glass or polymer film. A radiation thermometer that receives radiant energy, 5 a storage means for storing the output of the radiation thermometer 4, and 6 a translucent body 2 from which the output of the radiation thermometer 4 is stored.
This is a calculation means for calculating the true temperature of the temperature.

The measurement principle here is as follows.

The temperature of the semitransparent body 2 is T, the reflectance of the front surface is ρ ₁ , the reflectance of the back surface is ρ ₂ , the transmittance is τ, and the temperature of the mirror 3 is
T ₀ , the reflectance is ρ ₀ , the temperature of the wall 1a is T _W , the emissivity is ε _W , and the radiant energy from the semi-transparent body 2, the mirror 3, and the wall 1a is E(T), E(T ₀ ), If E(T _W ) and the radiant energy received by the radiation thermometer 5 are E(S), then the following equation holds in consideration of multiple reflections between the semitransparent body 2 and the mirror 3.

E(S)={(1−ρ ₁ −τ)+(1−ρ ₂ −τ)ρ ₀ 〓/
1−ρ ₀ ρ ₂ }E(T)+1−ρ ₀ /1−ρ ₀ ρ ₂ τE(T ₀ ) +ε _W (ρ ₁ +τ ² ρ/1−ρ ₀ ρ ₂ )E(T _W ) =( 1
−α−β)E(T)+ε _W αE(T _W )+βE(T ₀ )……(1) Here, α=ρ ₁ +ρ ₀ /1−ρ ₀ ρ ₂ τ ² , β=1−ρ ₀ /1−ρ ₀
ρ ₂ τ……(2).

In other words, in equation (1), the first term, second term on the right side,
The third term is, respectively, from the semitransparent body 2 of thermal radiation,
The coefficients 1-α-β, α, and β represent the contribution rates from the wall surface 1a and the mirror 3 on the back side.

Calculating E(T) from equation (1) yields the following equation.

E(T)=E(S)−ε _W αE(T _W )−βE(T ₀ )/1−α−
β...(3) By the way, if the output of the radiation thermometer 4 when the semitransparent body 2 is not present is E(S ₀ ), then the following equation holds true considering only the mirror 3.

E(S ₀ )=ρ ₀ ε _W E(T _W )+(1−ρ ₀ )E(T ₀ )
……(4) From this, ε _W E(T _W )=E(S ₀ )−(1−ρ ₀ )E(T ₀ )/ρ…
...(5), and by substituting this equation (5) into equation (1) and rearranging it, we get the following equation.

E(S)=(1-γ-δ)E(T)+γE(S ₀ )+δE(T ₀ ) ……(6) Here, γ=α/ρ ₀ , δ=α+β−γ ……(7 ). If the back surface is made up of mirror 3, the third term in equation (6) can be almost ignored; for example, ρ ₁ =ρ ₂ =0.2, τ=0.4,
If ρ≧0.8, then δ≒0, and equation (6) becomes as follows.

E(S)=(1-γ)E(T)+γE(S ₀ )...(8) From this, E(T) can be found as follows.

E(T)=E(S)-γE(S ₀ )/1-γ ...(9) According to equation (9), the output E(S ₀ ) is stored in the storage means 5,
By correcting the output E(S) when the semitransparent body 2 is present, the influence of the wall surface 1a can be removed.

The operation of the apparatus of FIG. 1 is as follows.

Before measurement, the reflectance ρ ₁ of the transparent body 2,
ρ ₂ , the transmittance τ, and the constant γ based on the reflectance ρ ₀ of the mirror 3 are input as the set values of the calculation means 6, and the output E (S ₀ ) of the radiation thermometer 4 when the semitransparent body 2 is not present. is stored in an appropriate storage means 5.

Next, during measurement, the calculation means 6 uses the output E(S) from the translucent body 2 of the radiation thermometer 4 as the output E(S) from the storage means 5.
(S ₀ ), and based on the constant γ, perform a correction calculation as shown in equation (9) to obtain E(T), and from this, the true temperature T of the transparent body 2
It can be found by calculating.

It is assumed that the temperature of the wall surface 1a does not change significantly before and during the measurement, and if it is not possible to set δ≈0, the temperature T may be determined based on equation (6), taking δ and T ₀ into consideration. Further, the calculation means 6 and the like may be configured with a microcomputer.

(5) Summary of the Invention As described above, the present invention provides a mirror on the back side of the semitransparent body, and the radiant energy output from the semitransparent body of the radiation thermometer is reflected in the radiation thermometer without the semitransparent body. This is a temperature measurement device that measures the true temperature of a transparent body by correcting the output, reflectance and transmittance of a semi-transparent body, reflectance of a mirror, etc. using calculation means.

(6) Effects of the invention By providing a mirror on the back side of the semitransparent body, the apparent emissivity of the semitransparent body is increased and the influence of heat radiation from the back side is removed. The true temperature of a transparent body can be measured with high precision. In addition, there is no need to measure the temperature of the wall surface.
When will it become so cheap and reliable? In particular, it has no specific absorption band, is effective for low temperature measurements, is suitable for measuring the temperature of semitransparent objects in general, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention. 1...Wall, 2...Semi-transparent body, 3...Mirror, 4...Radiation thermometer, 5...Storage means, 6...Calculation means.

Claims (1)

[Claims] 1. A mirror provided on the back surface of a semi-transparent body, a radiation thermometer that receives radiant energy E(T) etc. from the semi-transparent body, and an output E(S) of this radiation thermometer. is the output E (S0) when the semitransparent body is not stored in the storage means, the reflectance ρ1, ρ2 of the front and back surfaces of the semitransparent body, the transmittance τ, and the constant γ due to the reflectance ρ0 of the mirror. and a calculation means for calculating the temperature T of the semi-transparent body by performing a correction calculation based on E(T)=[E(S)-γE(S0)]/(1-γ). [Here, γ=ρ1/ρ0+ ^τ2 /(1−ρ0ρ2)].