JPS5932898Y2 - multicolor radiation thermometer - Google Patents

Description

[Detailed explanation of the invention] With conventional radiation thermometers, when the object to be measured is a non-black body, the surface temperature cannot be determined unless the emissivity of the surface of the object in that state is known. Can not.

Therefore, in such a radiation thermometer, if oxides etc. are present on the surface, and the proportion of these inclusions changes over time, the average emissivity of the surface will also change, so the surface temperature will change. measurement was no longer possible.

The present invention relates to a radiation thermometer that can measure surface temperature even under such conditions.

This polychromatic radiation thermometer consists of an objective system 1 made up of a lens or a concave mirror, a spectrometer 2 made up of a prism, a diffraction grating, or a filter, and a radiation detection device made up of a composite detection element such as a plurality of radiation detection elements or a photodiode array. The container 3 is configured as shown in FIG.

In the configuration shown in FIG. 1, the radiation from the object to be measured 4 is imaged by the objective system 1 on the entrance slit surface of the spectrometer 2, and the spectrometer 2 separates the radiation into radiation in two or more wavelength bands. , radiation having different wavelength bands is incident on each detection element of the radiation detector 3.

In this polychromatic radiation thermometer, the output of each detection element obtained in this way is amplified, and the output of each detected element is amplified.
Obtain a signal proportional to the spectral radiance of the object to be measured.

The spectral radiance at each wavelength can be calibrated using a blackbody furnace for radiation thermometer calibration, and by comparing this calibration value with the measured spectral radiance, the brightness temperature of the measured object 4 at that wavelength can be determined. Seek.

The surface temperature of the object to be measured 4 is determined by the brightness temperature at each wavelength,
It is calculated from the emissivity of each component present on the surface.

Next, the measurement principle will be explained using the case where the inclusion is one component as an example.

For a measured object with one component of inclusions on the surface, two wavelengths λ7
．． The spectral radiance L(λ1) of the surface appearing at λ2, L
(λ2) is (AE11+BE1□)P(λ0.T)-L(λ1)
(1) (AE21 + BE22) P (λ2.T
)-L(λ2)(2)A=1-B
(3) becomes.

Here, Ell and E2□ are the emissivities for wavelengths λ1 and λ2 in the state where inclusions are removed from the object to be measured, and E
1□ and E22 are the emissivities aligned with the wavelengths λ1 and λ2 of the inclusion, P(λ1.T) and P(λ2.T) are the temperature T
The spectral radiance aligned with the wavelengths λ1 and λ2 of a black body, B is the area ratio occupied by inclusions.

The relationship between spectral radiance and brightness temperature is L(λ1)-P(λ1.S1) (4)L
(λ2) -p (λ2.S2) However, Sl and S2 are λ1 and the brightness temperature of the object to be measured P(λ, T) is calculated from the Wien equation (5) P(λ, T) at the wavelength of λ2 Since it is expressed as C1λ−”exp(2 ears) C2=0.014388 tn′ K, we can eliminate A and B from equations (1), (2), and (3), and obtain (4), (5), ( 6) By substituting the expression, or is obtained.

Equations (7) and (8) are Ell 1 Ej21 E2
11 If E22 has been measured in advance and is known, then
This shows that the true temperature T of the surface is determined by the function T=F(Sl, S2) (9) of only the brightness temperature 81 + 82.

Therefore, by calibrating the radiation thermometer in advance and determining the relationship between the output of each radiation detector and the brightness temperature at each wavelength, the surface temperature T can be calculated regardless of the proportion of inclusions.

In this polychromatic radiation thermometer, the emissivity El 1 , Et
2 (+1 or 2) wavelength band λi and Ej
.

Wavelength band λj where the difference in Ej2 (J'=2 or 1) is large
By appropriately selecting and measuring (i\j), the surface temperature T can be determined with high accuracy.

The value of T can be easily determined from the measured values of Sl and S2 by using a table or the like, and can also be directly read by adding an arithmetic circuit 6.

This multicolor radiation thermometer uses three wavelengths to inscribe a brightness temperature of 8 for each wavelength in the case of a measured object with two components.
1 + S2 + S3, the true temperature T is (
9) In the same manner as the equation was derived, Sl, S2. It can be expressed as a function of S3: T=F(Sl, S2.S3) (10)
Then, the true temperature T can be calculated.

Similarly, when the inclusion is n component, the brightness temperature S1 of the (n+1) color. S2. ......, from the measurement of Sn, Sn+1, in principle T=F(S,, 82..--8n, Sn+1) using the following formula.
(]υTrue temperature T is found.

In actual measurements, when there are three or more components of inclusions, the calculated value of the true temperature T is greatly influenced by measurement errors.

However, even in this case, T1=F(S, , S2. S3) (
1,2)T,,=F (S2.S3.S4)
(1,3)T3=F(S3.S4.Sl)
(14) T4 = F (S4, 81
, S2 ) As shown in (15), the brightness temperatures 81 , S2 , S3 + S4 of the four colors are combined to obtain the true temperature T1. T2. T3. By calculating and comparing T4, it is possible to determine the presence or absence of the third and subsequent components, and it is possible to remove abnormal values caused by foreign substances that are mixed in at a low frequency.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the multicolor radiation thermometer of the present invention. In FIG. 1, 1 is an objective system, 2 is a spectroscope, and 3 is a radiation detector composed of a plurality of radiation detection elements.

Claims (1)

[Scope of utility model registration request] A spectrometer that separates radiation from an object to be measured into two or more wavelength bands, and two or more radiation detection elements that detect the radiance of each of the separated two or more colors. By calculating the proportion of inclusions based on the spectral radiance signal detected by each detection element, it is possible to measure the surface temperature of the object to be measured as the proportion changes. Features a multicolor radiation thermometer.