JPS59221628A - Method and device for measuring surface temperature - Google Patents

Abstract

PURPOSE:To measure the temperature of a material to be detected accurately by finding the temperature from the amount of radiant heat arriving at a detection part through an optical path member when the object end surface of the optical path member contacts the material to be detected. CONSTITUTION:The optical path member 6 is a solid optical rod molded of a heat-resistant optical path material, and its outer circumferential surface is covered with a light shield member 10 except both end surfaces. Heat radiation light from the surface of the material to be detected enters the optical member 6 from the object end surface and is projected upon an optical fiber 14 from the projection end surface 12. The heat radiation light guided through the optical fiber 14 is transduced by a transducer 13 into temperature, which is outputted to a temperature display device 8. A contacting state detecting means 9 grasps the point of time when the object end surface 11 of the optical rod 6 contacts the surface of the material to be detected. Then the temperature at this time is regarded as the surface temperature of the material to be detected.

Description

[Detailed description of the invention] The present invention relates to a surface temperature measuring method and apparatus.

As methods for measuring the surface temperature of a material to be tested, a contact method using a thermoelectric element and a non-contact method using a radiation thermometer are well known.

With the above contact method, temperature measurement accuracy is affected by the state of thermal contact between the temperature-sensing part and the surface of the material being tested, so it is difficult to expect high-precision measurement, and the response time is slow, taking several seconds. It had

On the other hand, the non-contact method is affected by disturbance factors such as fluctuations in surface emissivity, inclusions in the optical path such as dust and mist, and background light such as furnace light and sunlight, making high-precision measurement difficult. It was difficult.

In order to eliminate the above-mentioned disturbance factors, as shown in Figure 1, a bowl-shaped surface is used that multiple-reflects the emitted light with a cavity (inner surface plated with metal) (1) that has a high reflectance and increases the apparent emissivity. Thermometers (2) are well known. but,
This thermometer (2) had a blanket (heat retention) effect and dirt on the plated surface, which resulted in a decrease in measurement accuracy.

Furthermore, as shown in Fig. 2, a sighting tube type surface thermometer (4) is well known which attempts to block background light through the tube (3) K and clean the optical path by gas purging to remove disturbance factors. However, it was difficult to measure the true temperature due to the cooling effect of the purge gas on the surface of the test material (5).

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a surface temperature measuring method and an apparatus therefor, which solve the above-mentioned problems and enable highly accurate measurement.

Therefore, the feature of this method is that the thermal radiation of the specimen is transmitted to the detection part through an optical path member whose outer periphery other than both end faces is shielded from light and filled with optical material, and reaches the detection part. A detection means is provided that determines the temperature of the material to be inspected from the amount of heat radiation and detects when the objective end surface of the optical path member comes into contact with the material to be inspected. The device is characterized in that it has an optical path member that transmits the thermal radiation of the specimen to the detection part, and the outer periphery of the optical path member other than both end faces is covered with a light shielding member. and filled with optical material.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

What is shown in FIG. 8 is a schematic diagram of a surface temperature measuring device that is directly used to carry out the surface temperature measuring method of the specified invention.

The device mainly includes an optical path member (6), a detection section (7), a temperature indicator (8), a contact state detection means (9), and the like.

The optical path member (6) transmits thermal radiation from the surface of the test material (5) to the detection section (7). The optical path member (6) is made of heat-resistant MgO (melting point: 2800'C), sapphire (melting point: 2080°C), quartz (melting point: 1470°C).
It is a solid optical rond molded from optical materials such as.

The outer peripheral surface of this quad (6), except for both end surfaces, is covered with a light shielding member αO such as metal vapor deposition or metal tape. Therefore, background light does not enter into the interior from the outer peripheral surface of the iron (6). One end surface of this rond (6) is the opposite end surface (
6), thermal radiation from the surface of the object to be inspected (5) enters the optical rond (6) from the α force of the objective end surface, and is emitted to the outside from the output end surface (2) of the other end surface.

The detection unit (7)K has a converter 0, and the converter (2)
and the optical rond (6) of the optical path member is an optical fiber α→
connected with. Optical arad (6) and optical fiber α
They are connected by a connector aυ to prevent light from entering from the outside. The output end face 0 of the optical rod (6) and the end face of the optical fiber 0 face each other, and a condenser lens αQ is interposed between the two to improve coupling efficiency.

The converter αJ converts the thermal radiation guided by the optical fiber α4 into temperature, and there are two conversion methods.
I have a good knowledge of it. In the present invention, either method may be adopted.

One of them is brightness temperature conversion. This method calculates the temperature from the light intensity at a single wavelength, and is based on Blank's formula, which assumes that there is a 1:1 correspondence between the temperature of an object and the intensity of thermal radiation.

In this brightness temperature conversion, it is necessary to correct in advance the loss of light amount due to the optical rod (6), condenser lens (to), and optical fiber A4K, but these corrections are easy.

The other one is color temperature conversion. This method determines temperature from the relative ratio of light intensities at multiple waves, and fixes the wavelength distribution of thermal radiation, that is, the shape of what is called ``color'' in the visible range.

In this case as well, the spectral transmission characteristics of the optical system up to the converter a3 can be properly corrected by prior calibration.

For both the brightness temperature and color temperature above, the test material is a black body (emissivity =
If 1), it matches the true temperature, but since the actual object is an imperfect radiator, it is necessary to accurately determine the emissivity value.

The converter plate is connected to a temperature indicator (8), and the amount of heat radiation is converted to temperature by the converter (2) and displayed on the temperature indicator (8).
8). The temperature display (8) is a digital display or a printer.

The contact state detecting means (9) is for detecting the point in time when the objective end face (b) of the optical rod (6) comes into contact with the surface of the material to be inspected (5). The conductive light-shielding member coated with the i!
The temperature indicator (8) is connected to the temperature indicator (8). It is also possible to hold the temperature value displayed on the temperature indicator (8) by monitoring the contact resistance with a recognition device and creating a trigger signal when the contact is made.

The contact state detection means (9) connects an eddy current displacement meter, a capacitance displacement meter, an optical displacement meter, etc. to an optical rod (6).
This can also be achieved by attaching the K to create a trigger signal upon contact.

To measure the temperature of the surface (5) of a material to be tested using the surface temperature measuring device according to the present invention, first, the objective end surface αD of the optical rod (6) is brought close to the surface (5) of the material to be tested. Thermal radiation from the surface of the material to be inspected (5) enters the rod (6) from the objective end surface 0D of the optical rod (6), exits from the output end surface (to), and passes through the condenser lens αQ to the optical fiber α. input to the converter α through the optical fiber
3. In converter 0, the amount of heat radiation is converted into temperature, which temperature is output on a temperature indicator (8).

Furthermore, when the optical rod (6) is brought closer to the surface (5)K of the test material and the objective end surface αD is brought into contact with the surface (5) of the test material, the light shielding member αO on the outer peripheral surface of the optical rod (6) and the test material surface(
5) is short-circuited, the recognition device αη issues a trigger signal at the time of contact, the point of multiple contact is determined by this, and the temperature at that point is taken as the temperature of the surface of the material to be inspected (5). .

In the above measurement, when the surface temperature is certified, the optical rod (6)
Since the objective end surface (6) and the surface of the test material (5) are in contact with each other, the thermal radiation from the surface of the test material (5) directly enters the optical rod (6). Therefore, it is not affected by disturbance factors such as dust and mist in the atmosphere. Since the optical system optical path of the optical rod (6) and the optical fiber α fathom is shielded from light from the outside, it is not affected by background light. Furthermore, since the objective end surface (b) of the optical rod (6) only contacts the surface (5) of the specimen, no blanket effect occurs.

It should be noted that the temperature of the p1 test material surface (5) decreases due to contact between the objective end surface (b) and the test material surface (5), but since the temperature is measured at the moment of contact, the temperature drop does not occur. There is no effect. This is clear from the experimental results shown in FIG. In other words, in the case shown in Fig. 4, a thermocouple (type: 10.85' wire pair) is welded to the surface of the material to be tested (5), and the thermocouple is attached by touching an optical rod (6) near the position. The upper line in the figure is the surface temperature of the sample measured by the thermocouple, and the lower line is the temperature measured by this device. The symbol a force in the same figure! A trigger signal indicates when the touch is made, and a trigger signal indicates when the code is separated.

It can be seen that the temperature indicated by the thermocouple is cooled by the optical rod (6) and drops at the moment of contact. It can be seen that the temperature indicated by this device also gradually decreases during contact, but if the temperature at the time of contact is taken as the surface temperature, it can be seen that there is no effect.

Note that a two-color thermometer was used as the converter α3 in the above experiment. In addition, there is a risk that the light intensity up to converter 0 may change over a long period of time due to scratches on the end surface of the optical rod (6) or partial breaks in the fibers of the optical fiber α4. Conversion is more advantageous.

The one shown in Fig. 5 is an optical rod (6) whose objective end surface (b) is curved.
By giving a curvature to the surface, multi-touch operation can be facilitated.

It should be noted that the invention is not limited to the above embodiments.

According to the present invention, it is possible to reliably exclude the inclusions in the optical path and the background light among the inclusions in the optical path and the background light which are disturbance factors to the indication of the radiation thermometer, and it becomes possible to measure the temperature accurately. . Furthermore, it is extremely superior to contact type surface thermometers using thermoelectric elements in terms of quick response time and no need to create a thermal equilibrium state.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing a conventional bowl-shaped surface thermometer, Figure 2
The figure is an explanatory diagram showing a conventional sighting tube type surface thermometer, Figure 8 is a configuration diagram showing a contact type radiation thermometer according to the present invention, and Figure 4 is a graph showing the experimental results of the invention. Example of Output of Temperature Signal When Rod Contacts FIG. 6 is a sectional view showing another embodiment of the optical rod according to the present invention. (5)...Test material surface, (6)...Optical path member (optical rod), (7)...Detection section, (9)...Contact state detection means, QO...Light blocking member , wholesale...objective end face, (
2)...Emission end surface.

Claims (1)

[Claims] 1. Thermal radiation of the specimen is transmitted to the detection section through an optical path member whose outer periphery other than both end surfaces is shielded from light and filled with an optical material, and the amount of thermal radiation that reaches the detection section. A detection means is provided for determining the temperature of the material to be tested and detecting when the objective end face of one optical path member comes into contact with the material to be tested. A surface temperature measuring method characterized by: 2. A surface having an optical path member that transmits thermal radiation of the test material to the detection part, the outer periphery of the optical path member other than both end surfaces being covered with a light shielding member and filled with an optical material. Temperature measuring device.