JPH0465329B2 - - 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 In view of the above points, 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 precision using a mirror.

(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 surface 1a of the wall 1. 5 is a radiation thermometer that receives the radiant energy from the translucent body 2; 6 is the output of the radiation thermometer 5, the output of the temperature measurement means 4, etc.; This is a calculation means for calculating the true temperature of the transparent body 2.

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
To, the reflectance is ρ ₀ , the temperature of the wall 1a is Tw, the emissivity is ε _w , and the radiant energy from the semitransparent body 2, mirror 3, and wall 1a is E(T), E(To), E(Tw ), and if the radiant energy received by the radiation thermometer 5 is 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 τ/1
−ρ ₀ ρ ₂ }E(T) +1−ρ ₀ /1−ρ ₀ ρ ₂ τE(To) +ε _w (ρ ₁ +τ ² ρ/1−ρ ₀ ρ ₂ )E(Tw) = (1−α −β)E(T)+ε _w αE(Tw)+βE(To)
...(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, the second term on the right side,
The third term is, respectively, from the semitransparent body 2 of thermal radiation,
This is the contribution from the wall surface 1a and the mirror 3 on the back side, and the coefficients 1-α-β, α, and β indicate the contribution rate.

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

E(T)=E(S)−ε _w αE(Tw)−βE(To)/1−α−β
...(3) Also, ρ ₁ = ρ ₂ = 0.2, τ = 0.4, 1−α−β,
The contribution rates of α and β to ρ ₀ are shown in Figure 2. In other words, if the reflectance ρ ₀ of the mirror 3 is sufficiently large and its temperature To is sufficiently smaller than the temperature T of the semitransparent body 2 (ρ ₀ ≧0.9, To < T), the third term on the right side of the third equation can be ignored. , is the following equation.

E(T)=E(S)−ε _w αE(Tw)/1−α−β ……(4) If the wall surface 1a is isothermal and uniform, (1),
In equations (3) and (4), it may be assumed that ε _w ≒1.

In this way, the output E(S) of the radiation thermometer 5 is expressed as (3),
By performing correction according to equation (4), the true temperature T of the transparent body 2 can be determined.

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

In advance, the reflectances ρ ₁ and ρ ₂ of the transparent body 2, the transmittance τ, the constants α and β based on the reflectance ρ ₀ of the mirror 3, and the wall surface 1a.
The emissivity ε _w and the like are input to the calculation means 6 as set values. Next, the output Tw of the temperature measuring means 4 is input to the calculating means 6 and converted into E(Tw), and the calculating means 6 converts the output Tw from the transparent body 3 of the radiation thermometer 5 into E(S). For the output, E(Tw),
Based on the constants α, β, etc., perform a correction calculation as shown in equation (4) to obtain E(T), and from this, the true temperature T of the transparent body 2
It can be found by calculating.

In addition, if the temperature To of mirror 3 cannot be ignored,
The temperature To may be measured by another temperature measuring means, converted to E(To) by the calculation means 6, and calculations as shown in equation (3) may be performed. Also, if we set ε _w ≒ 1, then (3),
Equation (4) can be simplified. In addition, the calculation means 6 etc.
It may also be configured with a microcomputer or the like.

(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 measured by the output of the wall temperature measuring means and the semitransparent body. This is a temperature measurement device that measures the true temperature of a transparent body by correcting it using calculation means using reflectance, transmittance, reflectance of a mirror, etc.

(6) Effects of the invention By providing a mirror on the back surface of the semi-transparent body, the apparent emissivity of the semi-transparent body is increased, the influence of heat radiation from the back surface is eliminated, and the influence of heat radiation from the wall surface is also reduced. Since it is corrected and removed, the true temperature of the semi-transparent body can be measured with high accuracy with a simple configuration. 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 drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram. 1...Wall, 2...Semi-transparent object, 3...Mirror, 4...
Temperature measuring means, 5... Radiation thermometer, 6... Calculating means.

Claims (1)

[Claims] 1. A mirror provided on the back of the semi-transparent body and a wall temperature
temperature measuring means for measuring Tw, and radiant energy E(T), E(Tw) from the semitransparent body and wall surface;
A radiation thermometer that receives light such as the output E(S) of the radiation thermometer, E(Tw) obtained by converting the output Tw of the temperature measuring means into radiant energy from the wall surface, and the front and back surfaces of the semitransparent body. The reflectance of ρ1,
Based on ρ2, transmittance τ, reflectance ρ0 of the mirror, and emissivity εw of the wall surface, perform the correction calculation E(T)=[E(S)−εwαE(Tw)]/(1−α−β). and a calculation means for calculating the temperature T of the semi-transparent body [here, α=ρ1+ρ0τ ² /(1−ρ0ρ2), β=(1−ρ0)τ/(1−ρ0ρ2) ].