JPS62226023A - Emissivity measuring system - Google Patents

Abstract

PURPOSE:To make it unnecessary to heat an object to be measured, by applying radiant light beams to the object to be measured, measuring a reflected light beams, and a radiation energy from the object to be measured, by a detector, and calculating an emissivity from its measured quantity. CONSTITUTION:An optical system (1) is added coaxially to an optical system (2) in order to measure an emissivity. As for light beams which have been applied to an object 1 to be measured, reflection and absorption are executed in a ratio which is determined by the emissivity. The light beams which have been reflected pass through a scanner 2 and the optical system (2) and made incident on a detector 3, and converted to an electric signal. Also, energy radiated from the object 1 and other energy are made incident on the detector 3. In this way, first of all, the substance which has an emissivity '0' such as a mirror is placed on the object 1, and subsequently, that which has an emissivity '1' such as a black body (paint) is placed, the light beams are led to the detector 3, respectively, and its emissivity is derived by a prescribed expression. Accordingly, it is unnecessary to heat the black body to a temperature being equal to the object, and to heat object points to a uniform temperature in case of a multipoint measurement, and even in case of an object which cannot be heated, the emissivity can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring emissivity, which is a constant specific to a substance.

[Summary of the invention]

The present invention heats the measured object by irradiating the measured object with infrared rays, detecting the reflected light and radiant energy from the measured object, and calculating the emissivity from the detected amount. This makes it possible to measure emissivity without having to worry about it.

[Conventional technology]

Measurement of emissivity is necessary when measuring the temperature of a substance with a radiation thermometer, and conventionally this has been done using the following procedure.

(al) First, the object to be measured is heated to a certain temperature.

(b) Measure the radiant energy of the black body at the above temperature using a detector.

(C1 Radiant energy from the object to be measured is measured by a detector.

((1) Calculate the emissivity using the following formula.

(cl When measuring multiple points, the above fa1
The term heating is performed with all target points at a uniform temperature.

[Problem that the invention seeks to solve]

The conventional method described above has the following drawbacks.

(b) The object to be measured must be heated, and an isothermal fish body is required.

(b) In the case of multi-point measurement, it is necessary to heat the target points to a uniform temperature.

(c) Heating in (a) and (b) above is not easy.

(d) Therefore, it is difficult to measure the emissivity of objects that cannot be heated.

[Means for solving problems]

The present invention irradiates an object to be measured with radiation light from an infrared light source with constant brightness, measures the reflected light and radiant energy from the object with a detector, and calculates the emissivity from the measured quantity. I tried to calculate it.

[Effect]

This series of configurations makes it possible to measure emissivity without heating the object to be measured.

〔Example〕

FIG. 1 is a diagram showing the configuration of an optical system in an embodiment of the present invention. In the figure, the optical system (2) is the same as the optical system for focusing the radiant energy in the conventional LIKE radiation thermometer, and the optical system (2) is connected to the optical system (2) for emissivity measurement according to the present invention. This is an optical system added to the coaxial system. In these optical systems, the scanner scans the object to be measured with irradiated light and consists of a rotating mirror, and the detector converts incident energy into an electrical signal. In order to measure the emissivity according to this embodiment, light emitted from an infrared light source with constant brightness is used in the optical system (2).

(2) Irradiate the object to be measured via a scanner.

It is assumed that the object to be measured has an emissivity of ε and a temperature of To. The light irradiated onto the object to be measured is reflected and absorbed at a rate determined by the emissivity ε.

The reflected light passes through the scanner and optical system again.
ζ enters the detector. Not only this reflected light but also energy emitted from the object to be measured and other energies are incident on this detector. The infrared energy Wε incident on the detector can be written using Kirchhoff's law as shown in the following equation.

Wr −εW (To)+ <1−ε) W (TLP
)+(1-ε) W (Ta) +A ・-(1
) However, W (To), W (TLP) and W
(Ta) represents the energy from the object to be measured (temperature To), the infrared light source (temperature TLP), and the outside (temperature Ta), respectively, and A represents other disturbance components.

The first term in equation (1) is the radiant energy from the object to be measured with emissivity ε, his second term is the energy of the reflected infrared light emitted from the infrared light source, and the third term is the energy from the external It represents the energy of reflected infrared light emitted from the object to the measured object. (When formula 11 is rearranged, WE-ε(W ('T'o) -W (TLP)
W (Ta) 1+W (TLP) +W (
Ta ) +A ・------・ [2) Here, W (To ) −W (TLP) −W (T
a) −α.

W (TLP) + W (Ta) + A = β and (.

Now, if we put a mirror-like ε''-,0 object on the object to be measured, we get WE-β, so β can be found. -1, Wt-β=W (To) W (TLp) W
(Ta) becomes α, and α is found. Therefore, ε − (WE − β ) / α
... (ε is calculated from Te().

FIG. 2 is an electrical system configuration diagram in an embodiment of the present invention in which ε is determined from the output of the detector according to the above-mentioned principle. In the figure, the detector is the detector of FIG. The detector converts the infrared incident energy Wε into an electrical signal and sends it to the preamplifier (
A preamplifier) amplifies this. The output signal of the preamplifier is summed with the output signal of the D/to converter, and the summed signal is supplied to the ^/D converter and applied to one input of the comparator. A reference potential of 0 volts is connected to the other input of the comparator, and the comparator operates the counter by producing an output until the potentials of the inner inputs become equal. A clock signal is supplied to the counter from a clock signal source (not shown), and the counter counts the clock signal while receiving the output from the comparator. The count value of the counter is applied to a D/A converter, and the D/A converter outputs a °r analog signal of opposite polarity corresponding to the count value. This converter is designed so that even if the counter is down by one, it continues to output an analog signal corresponding to the count value at that time and maintains its state.

A computing unit is connected to the A/D converter, and the computing unit includes a register for data storage.

Next, the operation and operation of the above electrical system will be explained.

First, if we place an object to be measured with an ε average of 0, then Wε=β
However, when the output of the D/^ converter is 0, the potential at the 0 point is also β. The output of the D/A converter increases rapidly to -β
When it becomes equal to , the potential at the 0 point becomes 0, so the counter stops counting and the D/^ converter is kept in the state of outputting -β. Therefore, ε1−fO is later applied to the object to be measured.
If you place something that is not, Wε-β will appear at the 0 point. Next, when an object to be measured with ε=1 is placed, Wε-β-α appears at the 0 point, but the output of the D/^ converter does not change. This α is A/D converted and stored in a register within the arithmetic unit. Therefore, when an object to be measured with an unknown ε is placed, the calculator divides the output of the ^/mouth converter by the previously stored α and outputs (Wε-β)/α=ε. .

In the optical system configuration shown in FIG. 1, optical system 'ζ and optical system (2) may be any other optical system than the one shown in the figure, as long as the optical system (2) and the optical system (2) can coaxially receive radiation from an infrared light source. Further, although a scanner is included in the example shown in FIG. 1, the scanner is not necessarily required. Instead of the scanner, the object to be measured may be moved.

〔Effect of the invention〕

As explained above, according to the present invention, there is no need to heat the object to be measured when measuring emissivity, so all problems of the conventional method are solved, since no heater is required. That is, it is not necessary to heat the black body to the same temperature as the object to be measured, or to heat the object points to a uniform temperature in the case of multi-point measurement. Furthermore, it is possible to measure the emissivity of objects that cannot be heated.

Furthermore, in the case of multi-point measurement, the use of a scanner scans the emitted light from the infrared light source, making the measurement easier.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optical system in an embodiment of the present invention, and FIG. 2 is a block diagram of an electrical system in an embodiment of the present invention.

Claims (1)

[Scope of Claims] A first optical means for irradiating an object to be measured with radiation light from an infrared light source having a constant brightness; reflected light energy of the light irradiated to the object to be measured; and the object to be measured. It has a second optical means for inputting energy radiated from the object into the detector, and a calculation means for calculating the emissivity of the object to be measured from the incident energy input to the detector and converted into an electric signal. Emissivity measurement method.