JPH0449055B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in the scanner of a multichannel radiation thermometer using optical fibers.

<Prior art> Radiation thermometers that transmit measurement signals using optical fibers are not affected by electromagnetic fields, chemical atmospheres, etc., and there is no risk of ignition or explosion. It has many advantages compared to transmission.

FIG. 4 is an explanatory diagram of the configuration of a multichannel radiation thermometer conventionally used as one of such optical fiber radiation thermometers.

In Fig. 4, 1 is the object to be measured, 2
Containers a and 2b are placed close to the object to be measured 1 and fixedly house the ends of a plurality of optical fibers 3a to 3f at a predetermined distance. Optical fiber 3a
~3f is taken out from one end of the container and protects tubes 4a, 4
b, and the other end is fixed to through holes 6a to 6f arranged in a circular shape in the holding plate 5.
Note that, for example, gradient index lenses are provided at both ends of the optical fibers 3a to 3f, respectively. 7
is an optical fiber for scanning in which the central part of an optical fiber having a predetermined length is bent in opposite directions into an L shape, and one L-shaped part is fixed to the center of the first disk 8. . The outer circumference of the first disk 8 contacts the outer circumference of the second disk 9, and the second disk 9
The center of is fixed to the rotating shaft of the motor 10.
The rotation of the motor 10 is controlled by an optical fiber rotation control device 20 that operates based on commands from a computer 23. When the motor 10 rotates, the disk 9,
The other end A portion of the scanning optical fiber 7 rotates in a circular shape via the reference numeral 8, and the end portion A moves over the ends of the optical fibers 3a to 3f fixed to the holding plate 5 to separate from the object to be measured. scans the optical signal of The signal passing through the scanning optical fiber 7 is separated into two directions by a half mirror 11, and one of the lights passes through a lens 15a and a filter 16a and is converted into an electric signal by a photodiode 17a. The other light reflected by the half mirror is converted into an electrical signal by a lens 15b, a filter 16b, and a photodiode 17b. The electrical signal from the photodiode 17b is input to the computer 23 via the switch 18, amplifier 19, AGC (automatic gain control) circuit 21, and A/D converter 22, where necessary calculations are performed and output in the desired form. be done.

<Problems to be Solved by the Invention> However, in the above conventional example, since the scanning optical fiber 7 is rotated to scan the signal of the optical fiber fixed to the holding plate 5, a highly accurate positioning technique is not required. I need. For this reason, the structure is complicated, the signal is divided into two via a half mirror, which causes the signal to become weaker, and optical components such as half mirrors and lenses are required, which makes it expensive. There was a problem.

The present invention has been made in view of the above-mentioned prior art, and it is an object of the present invention to realize a radiation thermometer having a simple structure and an inexpensive multi-channel scanning function.

<Means for solving the problems> The configuration of the present invention for solving the above problems is as follows:
In a radiation thermometer that includes a plurality of optical fibers that transmit temperature signals from multiple points, a scanner that scans the signals from the optical fibers, and a radiation thermometer that sequentially converts the optical signals scanned by the scanner into electrical signals, the scanner comprises: two optical filters that transmit light with wavelengths of λ ₁ and λ ₂ ; a rotary plate having the same number of channel identification codes as measurement points; a means for rotating the rotary plate; and two adjacent points in the diametrical direction of the rotary plate. The number of channel identification codes is half the number of even-numbered equal parts of the rotating plate, and the number of channel identification codes is half the number of evenly divided parts of the rotating plate, and The two optical filters are arranged at positions connecting the center of the rotary plate and the center of the identification code on the side where the rotary plate first and then passes through the photointerrupter as the rotary plate rotates. This is a characteristic feature.

<Embodiment> FIG. 1 is an explanatory diagram a showing an embodiment of the present invention, and a diagram b showing the entire configuration in a perspective view of a scanner section. In FIG. 1, the same elements as those in the conventional example shown in FIG. 4 are given the same reference numerals. In this example, four measurement points are displayed. Signals from the object to be measured 1 are transmitted by optical fibers 3a to 3d and taken into the temperature converter 40 via connectors 41a to 41d, and gradient index lenses 16a to 16d provided at the tips of the temperature converter 40 are fixed (not shown). Fix it to the board at equal intervals around the circumference. 30 is a rotating plate disposed opposite to the fixed plate; this rotating plate 3
In the vicinity of the outer circumference of 0, cutouts 35a to 35d as identification codes (which may be protrusions or through holes) are sequentially formed at four locations on half the circumference of the circumference divided into eight, and these identification codes 35a, 35b 1st on the inner circumference of
and second optical filters 31a, 31b are formed. Numerals 17a to 17d are photoelectric conversion elements (for example, phototransistors), which are arranged opposite to the gradient index lenses 16a to 16d with the rotary plate 30 in between. 32a and 32b are photointerrupters that combine a light emitting element (for example, an LED) and a light receiving element, and are arranged facing the outer periphery of the rotary plate, and when the rotary plate 30 rotates, the identification code part blocks the light from the light emitting element ( or pass through) and is configured to emit an identification signal. This identification signal is input to the computer 23. Reference numeral 10 is a motor serving as a means for rotating the rotary plate 30, and reference numerals 19a to 19d are amplifiers that amplify electrical signals from the phototransistors 17a to 17d. Signals from the amplifiers 19a to 19d are selectively input to the variable gain amplifier 21 via a switch (not shown), and the A/D converter 2
2, the signal is A/D converted and input to the computer 23.

The relationship between the scanner section and the output signals in the above configuration will be explained based on FIGS. 2a and 2b. In FIG. 2, the same elements as in FIG. 1 are given the same reference numerals. In addition, in this figure, the identification code is formed in a convex shape on the outer periphery of the rotary plate 30, and the rotary plate is assumed to be rotating in the direction of the arrow.

First, the identification code 35a is the photointerrupter 3
When 2a (between the light emitting element and the light receiving element) is cut off,
Simultaneously with the identification signal, light with a wavelength of λ 1 of the optical fiber 3a passes through the first optical filter _31a formed on the inner circumference of the identification code and passes through the phototransistor 17a.
irradiate. The signal converted into an electrical signal by the phototransistor 17a is input to the amplifier 19a and amplified. Next, when the rotary plate rotates 1/8 and the identification code 35b shields the first photointerrupter 32a, the light with a wavelength of λ ₂ of the optical fiber 3a that passes through the second optical filter 31b simultaneously with the identification signal becomes a photointerrupter. The transistor 17a is irradiated and an electric signal corresponding to the intensity of the light is transmitted. In addition, the rotating plate is 2/8
When the identification code 35c shields the first photointerrupter 32a, light with a wavelength of λ ₁ from the optical fiber 3b passes through the first optical filter 31a and passes through the phototransistor 17 at the same time as the identification signal.
irradiate b, and when it rotates to 3/8, the optical fiber 3
Light with a wavelength of λ ₂ from the second filter 31b passes through the second filter 31b and irradiates the phototransistor 19b. Similarly, when the rotation reaches 4/8, the identification code 35a shields the second photointerrupter 32b, and at the same time as the identification signal, light with a wavelength of λ ₁ from the optical fiber 3c passes through the first optical filter and is transmitted to the phototransistor 1.
7c, and when the optical fiber 3c is rotated to 5/8, the light with a wavelength of λ ₂ from the optical fiber 3c passes through the second filter. If you rotate it further to 6/8, the identification code will be 35c.
passes through the second photointerrupter 32b, and the light with a wavelength of λ ₁ from the optical fiber 3d passes through the first filter and irradiates the phototransistor 17d.
When the phototransistor 17d is rotated, light having a wavelength of λ ₂ from the optical fiber 3d passes through the second filter 32b and irradiates the phototransistor 17d. In this way, the light from each optical fiber can be measured continuously.

According to the above configuration, it is possible to first determine the channel by switching the photointerrupter.

Figures 3a and 3b show the relationship between the scanner section and the output signal when there are eight measurement channels.In this example, the rotary plate is divided into 16 equal parts, and the half circumference of the rotary plate is shown in Figure 2. Identification codes 35a to 35h similar to the rotary plate are provided, and optical filters are provided at the position of the identification code 35a and at a position 22.5 degrees from the position. Incidentally, as the number of measurement channels is increased to eight, the number of corresponding phototransistors and amplifiers 19 is also increased to eight.

According to the above configuration, when the identification code 35a interrupts the photointerrupter, the signal from the optical fiber 3a passes through the first optical filter 31a formed on the inner circumference of the identification code at the same time as the identification signal and irradiates the phototransistor 17a. and the amplifier 19a is the first
The optical filter 31a transmits an electric signal according to the intensity of the light having a wavelength of λ ₁ that has passed through the optical filter 31a. Next, when the rotary plate rotates 1/16 and the identification code 35b shields the first photointerrupter 32a, the light passing through the second optical filter 31b simultaneously with the identification signal illuminates the phototransistor 17a, and the light of λ ₂ It transmits an electrical signal depending on the intensity of the wavelength of light.

In this way, the optical signals from the measurement target transmitted via the optical fiber are sequentially measured and input to the computer 23, and the desired signals (display display, e.g.
It can be extracted as a 20mA signal).

<Effects of the Invention> As specifically explained above with the examples,
According to the present invention, since there is no need to scan signals transmitted through an optical fiber with a rotating optical fiber, the present invention is advantageous in terms of accuracy and has a simpler configuration than the conventional example. Furthermore, since optical parts such as half mirrors and lenses are not required, the cost is reduced, and since there is no precision in positioning, it is easy to increase or decrease the number of channels.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram a showing one embodiment of the present invention, an overall configuration diagram b showing a perspective view of the scanner section, FIGS. 2 a and b are diagrams showing the relationship between the scanner section and output signals, and FIG. Figures a and b are diagrams showing other embodiments of the relationship between the scanner section and the output signal, and Figure 4 is a configuration explanatory diagram showing a conventional example. 1... Measurement object, 2... Container, 3a to 3d...
...Optical fiber, 4...Protection tube, 10...Motor,
17a-17d...phototransistor, 19a-
19d...Amplifier, 30...Rotary plate, 31a...
First optical filter, 31b...Second optical filter, 32a...First photointerrupter, 32
b...Second photointerrupter, 40...Temperature converter.

Claims (1)

[Claims] 1. A radiation thermometer that includes a plurality of optical fibers that transmit temperature signals from a plurality of points, a scanner that scans signals from the optical fibers, and a radiation thermometer that sequentially converts the optical signals scanned by the scanner into electrical signals. is a rotary plate having two optical filters that transmit light of wavelengths λ ₁ and λ ₂ and the same number of channel identification codes as measurement points, a rotating means for the rotary plate, and two points in the diametrical direction of the rotary plate. The photo-interrupter is arranged in close proximity and oscillates an identification signal when the channel identification code passes therethrough, and the number of the channel identification codes is half the number obtained by dividing the rotary plate into an even number, and
The two optical filters are arranged on the half circumference side of the rotary plate, and the two optical filters are respectively disposed at positions connecting the identification code that first and then passes through the photointerrupter as the rotary plate rotates, and the center of the rotary plate. A radiation thermometer that is characterized by: