JPS5834769B2 - Housiyaondokei - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation thermometer that measures unknown quantities including the surface temperature of an object at a certain distance by using radiant energy emitted from the object. It is.

Conventionally, the following devices are known in the art.

Total radiation temperature measures the energy distributed in a wide wavelength range around the maximum emission wavelength of the radiant energy from the measured object, and measures the surface temperature of the measured object according to Stefan Boltzmann's fourth power law. Total.

A part that measures the energy distributed in a limited wavelength range shorter than the maximum emission wavelength among the radiant energy from the object to be measured, and measures the surface temperature of the object to be measured according to Blank's radiation law. Radiation thermometer.

A two-color thermometer that measures the ratio of energy at two adjacent wavelengths among the radiant energy from an object to be measured, and measures the surface temperature of the object to be measured according to Blank's radiation law.

However, in these known devices, all of The surface temperature can be accurately measured due to the effects of absorption by substances such as moisture and carbon dioxide between the sensor and the detection part, as well as the effects of radiation emitted behind the object and transmitted through the object. It is not possible.

The present invention aims to realize an apparatus that can accurately measure unknown quantities such as surface temperature without being affected by these influences.

Another object of the present invention is to realize a device that can automatically measure surface temperature, etc., without the need for manual adjustment.

FIG. 1 is a configuration diagram showing an example of the principle of the present invention.

In the figure, 10 is an object to be measured, 20 is a condensing lens for condensing energy radiated from the object to be measured, and 3
0 is an integrating sphere, and 41, 42, and 43 are light receivers attached to the integrating sphere 30.

The light receiver 41 detects the radiant energy of wavelength λ1 out of the radiant energy synthesized within the integrating sphere 30, and the light receiver 42 detects the radiant energy of wavelength λ1.
detects the radiant energy of the wavelength λ2, and the photoreceiver 43 detects the radiant energy of the wavelength λ3.

In order to simplify the explanation, here, an example is shown in which three sets of light receivers are attached to the integrating sphere 30.

Regarding total radiation at all wavelengths, the following relationship holds between the temperature of a blackbody and the total energy radiated from a unit area according to Stefan Boltzmann's law.

Also, blank (Planck) or Wien (Wi)
According to the radiant of en), the radiant energy P of wavelength λ emitted from a blackbody object at absolute temperature T0 is generally expressed by equation (1).

In equation (1), C1 and C2 are constants, and their values differ somewhat as a result of measurement, but rRAD-IAT
ION PYROMENTRY and its
unde-rlying PRINCIPLES OF
RADIANTHEATTRANSFER” (THO
According to MAS-R-I (authored by ARRISON), it is.

Therefore, considering the radiant energy of surrounding objects surrounding the object to be measured 10, the radiant energy P1. P2°P3 can be expressed by equations (2), (3), and (4), respectively.

The radiant energy P that can be shown by these equations
can be represented in the form P=P(To, T1.ε, λ).

Then, the known wavelength λ1. λ2. Radiant energy P1. at λ3. P2゜P3 are both T.

, T1. Varies depending on ε. In the present invention, from the light receivers 41, 42, 43, the above equations (2), (3), and (4)
), and T such that the function equations (2), (3), and (4) are simultaneously satisfied.

, T1. The feature is that ε is calculated and unknown quantities To, T, .epsilon., etc. are obtained from this calculation.

FIG. 2 is a block diagram showing an embodiment for implementing the present invention.

In the figure, 21 is a sector for intermittent radiant energy entering the integrating sphere 30, and 51 (52, 53) is a light receiver 4.
1 (42°43)
2, P3), an amplifier 61(
62゜63) is a synchronous rectifier circuit, and amplifier 51 (52゜5)
3) is synchronously rectified by an intermittent signal from the sector 21.

71 (72, 73) is an A/D converter, which outputs a digital signal Ql (Q
2, Qs).

80 is a digital signal Q1. Q2. This is an arithmetic circuit that receives Q3 as an input.

This arithmetic circuit has a surface temperature T. , temperature T1 of surrounding objects,
It has a setting circuit that can set the emissivity ε to an appropriate value, and first set an appropriate T to these setting circuits.

, T1. Set the assumed value of ε, and convert this assumed value to (
2), (3), and (4) to obtain calculated values P1o, P2o, and P3o, respectively.

Next, digital signal Q1. Q2. Q3 is input, and the calculation shown in equation 5 is performed between it and the calculated value P10 j P2Oj P2O.

Then, in order to minimize the calculation result F obtained by equation (5), that is, equation (2), equation (3), and (4
) is initially assumed and set in the setting circuit so that the equations are satisfied at the same time.

, T1. The value of ε is corrected sequentially.

If you repeat the correction until finally F=0, the last corrected T in the setting circuit.

, T1. The true surface temperature T of the measured object is determined by the value of ε.
.

, the temperature T1 of the surrounding objects, and the emissivity ε.

81, 82, and 83 are the final revised Ts.

, T1. This is the output terminal from which ε is output.

In addition, in this embodiment, the arithmetic circuit 80 may utilize the arithmetic circuit of an electronic computer.

FIG. 3 is a block diagram showing another embodiment for implementing the present invention.

In this example, 31 is the second integrating sphere, 32, 33
34.35 is a blackbody furnace; 36 is a setting circuit for setting the temperature of the blackbody furnace 34; 37 is a setting circuit for setting the temperature of the blackbody furnace 35; 38 is the aperture degree of the aperture mechanism 32.33. In this setting circuit, the aperture mechanisms 32 and 33 are interlocked to operate in opposite directions.

90 is an arithmetic circuit which receives outputs XI, X2 . Using X3 as an input signal, calculations as shown in equation (6), for example, are performed.

91 is an indicator that indicates the calculation result of the calculation circuit 90.

The radiant energy from the blackbody furnace 34 and the radiant energy from the blackbody furnace 35 each pass through the aperture mechanism 3233 and enter the second integrating sphere 31, where they are combined.

The radiant energy Ps synthesized here is intermittently reflected by the sector 21 and enters the integrating sphere 41.

Therefore, the radiant energy P from the object to be measured 10 and the combined radiant energy Rs from the second integrating sphere 31 are alternately incident on the integrating sphere 30.

The photodetectors 41, 42 and 43 alternately detect the radiant energy in the wavelength range that they are responsible for, P and Ps,
Difference between the two (variation) Xl, K2. K3 is synchronous rectifier circuit 6
It is obtained from the output end of 1°62.63.

The arithmetic circuit 90 receives this signal X1. K2. With K3 as input, calculation is performed according to equation (6), and the result of this calculation is indicated to indicator 91.

In this device, if the setting values of the setting circuits 36, 37, and 38 are manually adjusted so that the indicated value of the indicator 91 becomes the minimum, then the setting values set in each of the setting circuits 36, 37, and 38 is the surface temperature T of the measured object, respectively.

, corresponds to the temperature T1 of the surrounding object and the emissivity ε of the object to be measured.

FIG. 4 shows an improved version of the device shown in FIG. 3 according to the present invention, which can automatically measure the surface temperature of the object to be measured, the temperature of surrounding objects surrounding the object to be measured, and the emissivity of the object to be measured. FIG. 2 is a block diagram of an embodiment of the invention.

In the device shown in FIG. 4, 85 indicates each synchronous rectifier circuit 61, 62.
．． 63 output x8. K2. Resistor networks 86, 87, and 88 each input K3.

85 to each output X1. X2. Integrators 36, 37, and 38 to which X3 is applied are setting circuits that input the outputs of these integrators.

These circuits are controlled by the setting circuit 36, 37, 3B so that the algebraic sum of the squares of the outputs Xl, X2°K3 of each synchronous rectifier circuit 6L62, 63 automatically becomes the minimum.

. T1. It constitutes a closed loop circuit (blackbody furnace control means) that controls the value of ε.

In addition, in the resistance network 85, the resistance values are R1, in order from the top.

R12 R13 R21 R22 R23 R31 R
32F R33, these resistance values may be fixed, but if necessary, the setting value T of each setting circuit 36, 37, 38 may be changed as shown in equation (7).

, T1. If controlled in conjunction with ε, the operation of the closed loop (servo system) can be made more stable.

However, K11 ~ 33: Constant According to this device, in each setting circuit 36, 37, 38, the final setting value (when the equilibrium state is reached) is the surface temperature T of the object to be measured. Temperature T of surrounding objects
1 and the emissivity ε of the object to be measured,
T without any manual adjustment etc.

, T1. ε can be measured accurately.

FIG. 5 is a configuration diagram showing an example of the principle of the present invention when considering the influence of moisture existing between the object to be measured 10 and the detection unit and ignoring the radiant energy from objects around the object to be measured. be.

In this case, the radiant energies PI, P2 . Since P3 is absorbed by water, it can be expressed by equations (8), (9), and (10).

However, al, a2. a3 is the wavelength λ0. λ2. Known spectral absorption coefficient of λ3 in water vapor.

X is the water content, and the water concentration and the object to be measured An unknown quantity determined by the sum of the distance between and the detection unit.

The radiant energy P that can be shown by these equations
can be represented by the form P=P (T□, e, X, λ).

Then, the known wavelength λ1°λ2. Radiant energy P1. at λ3. F, , P3 are all T.

, ε, and X. Therefore, the above formula (8), (9
), α0), Pl, P2. Since the value of P3 is clear from the output signals of the photodetectors 41, 42, and 43,
T such that equations (8), (9), and αO) are simultaneously satisfied.

, ε, and X, the unknown quantity T is obtained from this.

, ε, and X can be obtained. In addition, equation (8), (9
) and (10) are simultaneously satisfied.

, ε, and X may be calculated using the same method as described above.

In each of the above embodiments, there are three types of unknown quantities (To, Tt, ε, or T).

, ε, X), but even more n
To find the unknown quantities, if we assume other conditions for these unknown quantities and detect the radiant energy in different wavelength regions of the number n of unknown quantities, we can find a large number of unknown quantities using the same method. be able to.

In addition, the spectral sensitivity characteristics of each photodetector used in the present invention are as follows:
It is possible to use those with various characteristics as shown in FIG.

That is, as shown in FIG. 6A, each light receiver 41, 42,
The spectral sensitivity characteristics of 43 correspond to the wavelength range λ1. λ2.
A narrow range near λ3, and a wavelength range λ1 in charge as shown in the opening of FIG. λ2. Each has a spread around λ3, and as shown in Figure 6C, each has multiple wavelength regions (λ0, λ2...)
It is possible to use existing ones, or ones having different widths of wavelength ranges as shown in FIG. 6-2.

In short, it is sufficient that the spectral sensitivity characteristics of each photoreceiver are different from each other.

Note that these desired spectral sensitivity characteristics can be realized, for example, by changing the characteristics of a filter placed in front of the thermistor bolometer.

As explained above, according to the present invention, unknown quantities including the surface temperature of an object to be measured are known by simultaneously satisfying a plurality of functional expressions representing radiant energy. Unknown quantities, such as emissivity and temperature of surrounding objects, can be determined at the same time.

Further, the determined surface temperature is not affected by the emissivity of the object to be measured, the temperature of surrounding objects, etc., and is accurate.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of the principle of the present invention, Fig. 2 is a block diagram showing an embodiment for realizing the present invention, and Fig. 3 is a block diagram showing an example of the principle of the present invention.
4 and 4 are block diagrams showing other embodiments for realizing the present invention, FIG. 5 is a block diagram showing another example of the principle of the present invention, and FIG. 6 is a light receiving device used in the present invention. FIG. 2 is a diagram showing an example of the spectral sensitivity characteristics of the device. 10...Object to be measured, 20...Condensing lens, 21 Sector, 30...Integrating sphere, 41
,42゜43...Receiver, 51.52,53.
...Amplifier, 61, 62, 63...Synchronous rectifier circuit, 71,72゜73...D/A converter, 80...Arithmetic circuit.

Claims (1)

[Scope of Claims] 1. An integrating sphere into which the radiant energy radiated from the object to be measured is incident, and mutually different spectral sensitivity characteristics provided on this integrating sphere to simultaneously detect the radiant A. lugie synthesized within the integrating sphere. at least three sets of light receivers having a radiant energy detected by the light receivers, and a calculation means that receives as input signals related to each signal from each of these light receivers, and the calculation means is provided with a signal that represents the radiant energy detected by the light receivers. At least three or more predetermined function formulas are prepared, and these function formulas are made to correspond to the output signals from each of the light receivers, and the above-mentioned function formulas in these function formulas are A radiation thermometer that operates to calculate three or more unknown quantities, including the surface temperature of the object to be measured, so as to know the unknown quantities, including the surface temperature of the object to be measured. 2. An integrating sphere on which the radiant energy emitted from the object to be measured and the composite radiant energy obtained by combining the radiant energy emitted from at least two blackbody reactors are alternately incident;
At least three or more sets of light receivers installed in this integrating sphere and having mutually different spectral sensitivity characteristics that simultaneously detect the radiant energy synthesized within the integrating sphere, and a predetermined function equation from these three or more sets of light receivers. 2 for each output represented.
blackbody furnace control means for adjusting the temperature of the at least two blackbody furnaces and the degree of aperture of a throttle mechanism that throttles the radiant energy emitted from the blackbody furnace so that the algebraic sum of the products is minimized. , a radiation thermometer configured to determine the surface temperature of an object to be measured, the temperature of peripheral objects surrounding the object to be measured, and the emissivity of the object to be measured from the temperature and the degree of aperture of the blackbody furnace.