JPS6111368B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a dichroic radiant temperature system that separates the radiant energy from a measured object into two different wavelength bands and measures the ratio to determine the temperature of the measured object. It is related to the meter.

This type of dichroic radiation thermometer has the feature of reducing the influence of the emissivity of the object to be measured, but the required ratio is related to temperature and is a nonlinear characteristic of S.
The problem is that it is difficult to measure over a wide temperature range because it shows the characteristics of a letter shape.

In view of the above points, the present invention provides a rotary disk having three or more filters with mutually different transmission wavelengths in the middle of the propagation path of radiant energy from the object to be measured to the detection element, and also We have developed a dichroic radiation thermometer that can measure temperatures over a wide range by measuring the ratio of the radiant energies detected by each sensor and by arbitrarily switching the combination of radiant energies to be compared. The purpose is to provide

Next, an embodiment of the radiation thermometer according to the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of the mechanism of a dichroic radiation thermometer, in which an objective lens 2 is provided on the front of this thermometer 1, and a rotating disk 3 is provided behind the objective lens 2. The center of the disk 3 is connected to the rotating shaft 4a of the motor 4 and rotated at a constant speed, and an even number of 4 or more transparent windows 5 are formed at special distances from the center of rotation. .
In this embodiment, four transmission windows 5a, 5b, 5c, and 5d are formed as the transmission windows 5, and each transmission window 5a, 5b, 5c, and 5d is provided with a colored filter having a different transmission wavelength. 6a.6
b, 6c and 6d are inserted. As the colored filters 6a and 6b, here the filter 6a is
A filter that transmits only a wavelength of 2.15 μm is used, similarly, a filter 6b is a filter that transmits only a wavelength of 0.85 μm, a filter 6c is a filter that transmits a wavelength of 2.30 μm, a filter 6d is a filter that transmits only a wavelength of 1.00 μm, and a filter 6a and a filter 6c are used. , filter 6b and filter 6d are each set as one set. Furthermore, a detection element 8 is provided behind the rotary disk 3, and this detection element 8 is positioned on a straight line connecting the objective lens 2 and one of the transmission windows 5. This detection element 8 is a thermoelectric detection element such as a thermopile, a thermistor, or a bolometer, or a thermoelectric detection element such as Si, Pbs,
A photoelectric detection element such as PbSe is used, and the output of the detection element 8 is input to an amplifier 9.
Further, a synchronous signal generator 7 is provided close to the outer periphery of the rotary disk 3, and this synchronous signal generator 7
is the number corresponding to the transmission window 5, that is, four synchronizing signal generators 7a, 7a, 7 in this embodiment.
c, 7d are provided, and a proximity switch, phototube, etc. are used. These synchronizing signal generators 7a, 7
b, 7c, 7d are transmission windows 5a, 5b, 5c, 5d
When the transmission window 5 is located on a straight line connecting the objective lens 2 and the detection element 8, the corresponding signals _P1 to _P4 are output from the corresponding synchronization signal generators 7a to 7d, respectively. It is configured so that it can be used. The synchronous signal generators 7a and 7b are connected to the synchronous rectifier 11 via a changeover switch 10a, and similarly the synchronous signal generators 7c and 7d are connected to the synchronous rectifier 11 through a changeover switch 10b, and the synchronous signal P ₁ to _P4 are input to the synchronous rectifier 11, and the output signal e from the amplifier 9 is input to the synchronous rectifier 11.
Furthermore, two signals e ₁ and e ₃ are output from this synchronous rectifier 11.
is output, and this output is input to the division circuit 12.

Here, the changeover switches 10a and 10b serve as selection devices that select any two filters based on synchronization signals generated from the synchronization signal generators 7a, 7b, 7c, and 7d.

Further, the division circuit 12 is configured to select any two selected by the changeover switches 10a and 10b as selection devices.
It acts as an arithmetic device that calculates the ratio of two different specific wavelength bands and radiant energy transmitted through each filter.

The operation of the dichroic radiation thermometer 1 with the above configuration will be explained below.

The radiation energy from the object to be measured is transmitted to the objective lens 2.
When the rotary disk 3 is irradiated with the radiant energy, since the rotary disk 3 is always in a rotating state, this radiant energy passes through the transmission window 5 intermittently and is intermittently irradiated onto the detection element 8. Since filters 6a to 6b having different transmission wavelengths are inserted into the transmission window 5, the detection element 8 has a wavelength of 2.15 μm,
Radiation energy having a wavelength of 0.85 μm, a wavelength of 2.30 μm, and a wavelength of 1.00 μm is sequentially applied, and an output signal E corresponding to each amount of energy is output from the detection element 8. Here, if the changeover switch 10a selects the synchronous signal generator 7a and the other changeover switch 10b selects the synchronous signal generator 7c, the synchronous rectifier 11 selects the synchronous signal generator 7a, 7c. Output signals e ₁ and e ₃ corresponding to the wavelengths of 2.15 μm and 2.30 μm are selected by the signals P ₁ and P ₃ and are converted into DC signals and output to the division circuit 12, respectively. In this division circuit 12, the above two types of output signals e ₁ and e ₃ are divided, and the two types of output signals are
The ratio R(T) of e ₁ and e ₃ is output from the division circuit 12.

The ratio R(T) of thermal radiation in the wavelength bands of 2.15 μm and 2.30 μm has a practical characteristic in a low temperature range of 1000° C. or less, as shown in FIG. Also
When performing measurements in a high temperature range of 1000°C or higher, changeover switches 10a and 10b are switched to switch the synchronous rectifier 11
The synchronization signal P ₂ from the synchronization signal generators 7b and 7d,
By adding P ₄ , the same effect as above is performed, and this time it is output as the ratio R(T) of thermal radiation in the wavelength band of 0.85 μm and 1.00 μm.
The ratio of thermal radiation in this 0.85 μm wavelength band R
(T) has practical characteristics in a relatively high temperature range, and by switching the wavelength band to be measured in this way, it is possible to measure a wide temperature range without being affected by the S-shaped characteristics.

Next, a second embodiment of the radiation thermometer according to the present invention will be described with reference to FIG. Note that the same reference numerals are given to the same parts as in the first embodiment described above, and the explanation thereof will be omitted.

One of the colored filters 6 in this embodiment is a filter 6e that is a common comparison target, and is configured to be combined with other colored filters 6f, 6g, and 6h in sequence, and the position of the filter 6e is The synchronous signal generator 7e to be detected is directly input to the synchronous rectifier 11, and the other filters 6f, 6g,
Synchronous signal generators 7f, 7 detecting the position of 6h
g, 7h are input to the synchronous rectifier 11 via the changeover switch 10c. However, the changeover switch 1
By switching 0c, the radiant energy irradiated through the filter 6e and the other filters 6
Any one of the radiant energies irradiated via f, 6g, and 6h will be subjected to a division operation and output.

As explained above, according to the dichroic radiation thermometer according to the present invention, the rotary disk has three or more filters having different transmission wavelengths in the middle of the propagation path of radiant energy from the object to be measured to the detection element. The system measures the ratio of the radiant energies detected through each filter, and arbitrarily switches the combination of radiant energies to be compared. This has the effect of not being affected by the ratio characteristics related to the temperature of Since a ratio within a certain range is used, there is no risk of such undetectability occurring. Therefore, there is an effect that temperature measurement over a wide range is possible. In addition, in order to increase the sensitivity of the thermometer, it is better to separate the two wavelength bands used for measurement as much as possible, and it is advantageous to have them closer together to reduce drag on emissivity. Even with the inherent contradictions in the temperature characteristics of each combined wavelength band, each sensitive range can be used, providing sufficient resistance to emissivity without sacrificing sensitivity. It has the effect of gaining power.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the mechanism showing the first embodiment of the two-color radiation thermometer according to the present invention, FIG. FIG. 2 is a graph diagram showing ratio-temperature characteristics in a combination. 3...Rotating disk, 6...Colored filter, 7...Synchronizing signal generator, 8...Detecting element.

Claims (1)

[Claims] 1. Separating only the radiant energy in a specific wavelength band from the radiant energy emitted from the object to be measured,
In a dichroic radiation thermometer that measures the temperature of a measured object from the ratio of radiant energy in two specific wavelength bands obtained by separation, three or more filters are arranged to transmit only radiant energy in different wavelength bands. a detection element for detecting the arrangement position of the filter; a synchronization signal generation device for generating a synchronization signal based on the detection of the detection element; and a synchronization signal generated from the synchronization signal generation device. , a selection device for selecting any two filters from among the three or more filters, and a ratio of radiant energies of two different specific wavelength bands passing through the two filters selected by the selection device; A dichroic radiation thermometer comprising: a calculation device for calculating the temperature of an object to be measured. 2 The combination of two filters selected by the selection device is a combination of one common filter to be compared and another filter other than the common filter to be compared. A dichroic radiation thermometer according to scope 1. 3. The dichroic radiation set forth in claim 1, wherein the combination of two filters selected by the selection device is a combination of an even number of filters arranged in groups of two. thermometer.