JPS62145122A - Radiation thermometer - Google Patents

Abstract

PURPOSE:To measure exactly a temperature of a object to be measured, without cooling an optical path part of a transparent solid, by providing a measuring part for measuring a temperature of an optical path itself of the transparent solid. CONSTITUTION:A thermal radiation from a body to be measured 6 is led into a detector 7 through an optical path of a peep chip 2 and a straight light guide 3, and an output signal of the detector 7 is inputted to a display/converting part 8 through an output signal line 21. On the other hand, a temperature of a light guide itself, which has been measured by a thermocouple 18 is inputted to the display/converting part 8 containing a correcting computing element through a compensating lead wire 19. The display/converting part 8 derives a temperature of only the body to be measured 6, and displays it on a display part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radiation thermometer, and in particular, by introducing thermal radiation from an object to be measured into a detector through an optical path of a transparent solid, it is possible to The present invention relates to a radiation thermometer configured to detect and measure the temperature of an object.

[Prior Art] In general, when measuring the temperature of molten resin in plastic molding or the temperature of raw materials in a rubber raw material kneading machine, there are two methods: (1) measuring using a thermocouple; (2) measuring using a general method; Means for measuring from a distance from the object to be measured using a lens-based or mirror-based radiation thermometer, '3) JP-A-58-13772
As in the technology described in Publication No. 1 and Tokusho No. 60-23216, thermal radiation from a molten plastic polymer, which is an object to be measured, is introduced into a detector through a probe with an optical fiber or glass rod inserted, and a high temperature state is detected. Measures such as measuring the temperature of molten plastic polymers have been adopted.

[Problems to be Solved by the Invention] However, each of the conventional measuring means described above has the following problems, and none of them are satisfactory as measuring means.

First, in the method of measuring temperature by inserting a thermocouple into the object to be measured, the thermocouple responds slowly to temperature changes, so there is a risk of large measurement errors and wear and tear. It has the disadvantages of low resistance and easy wear and tear. Although it is possible to make the thermocouple have a structure with high (high) wear resistance, in this case, the responsiveness to temperature changes becomes significantly poor, causing measurement errors.

Next, in the case of a general lens-based or mirror-based radiation thermometer that measures the object at a distance, since it has an open space, stray light and reflected light from the outside enter, and gas smoke and smoke in the optical path enter. water droplets.

Due to the influence of flames, accurate measurements cannot be made. In addition, when measuring the temperature of molten resin or the temperature of rubber raw materials in a rubber raw material kneading machine, a window is required to ensure pressure resistance against the pressure of the object to be measured and wear resistance against flow. Condensation and fogging can form behind the windows, making accurate temperature measurements difficult. In addition, there are various problems such as the large attenuation caused by the air layer, making it impossible to expect accurate measurements.

Japanese Unexamined Patent Publication No. 58-137721, Japanese Patent Application No. 60-234
According to the techniques described in No. 6 and Utility Model Application No. 60-27631, the above-mentioned drawbacks of thermocouples are improved. However, the glass rod (light guide) itself made of sapphire, quartz, etc. constitutes a long cylindrical mutual reflection system, and reflection of light at the user interface due to the difference in refractive index is unavoidable. Therefore, although the emissivity of transparent solids such as sapphire, quartz, and MgO is small, the effective emissivity of the solid light guide is large. Therefore, when the temperature of the light guide is low, the thermal radiation of the light guide itself can be ignored. However, as the temperature of the light guide increases, the heat radiation of the light guide itself increases, and in extreme cases, the temperature of the light guide may exceed the temperature being measured. greater than the temperature of the object. In this case, the radiant energy from the object to be measured is smaller than the radiant energy from the light guide, and the error signal energy becomes larger than the required signal energy, making accurate measurement impossible. From this point of view, the technique described in Japanese Patent Application Laid-Open No. 137721/1983 also discloses a means for cooling the light guide by circulating a cooling medium. However, in the cooling method, (1) the cooling medium is It cannot be cooled unless a large amount is introduced,
The tip is extremely difficult to cool. (2) In molds, etc., the light guide is inserted into the mold which must be heated, so it is necessary to maintain the high temperature of the outer wall and cool only the light guide. is almost impossible in a narrow space. (3) Therefore, from the above points, it is possible to reduce the temperature by cooling to some extent, but it is extremely difficult to reduce the temperature to a point where the heat radiation of the light guide itself can be ignored. As a result, accurate temperature measurements cannot be made.

The present invention has been made in view of the problems of the prior art described above, and is a radiant temperature sensor that makes it possible to measure rapid and minute temperature changes with a fast response speed that is impossible with the conventional measuring means. This is an attempt to provide a measurement plan.

Means for Solving Problem E] The present invention is configured such that the temperature of an object to be measured can be detected by introducing thermal radiation from the object to be measured into a detector through an optical path of a transparent solid. The radiation thermometer is configured with 314 feet for measuring the temperature of the optical path itself of the transparent solid body separately from detection by the detector.

[Operation] According to the above configuration, the temperature of the object to be measured itself can be measured by correcting and correcting the temperature of the optical path itself of the transparent solid based on the detected value of the detection section.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

(First Embodiment) FIG. 1 is a cross-sectional explanatory diagram showing a first embodiment of a radiation thermometer 1 according to the present invention.

As shown in the figure, the radiation thermometer 1 consists of a beep chip 2, a light guide (straight light guide) 3, and an external protection rod 4.
a sensor part 5 consisting of a sensor part 5, a detector 7 for detecting thermal radiation emitted from an object to be measured 6 via the light guide 3, and a sensor part 5 for detecting the temperature at the tip of the light guide 3. It has a built-in thermocouple 8 for measurement and a correction calculation section for correcting and displaying the temperature display value based on the detected value of the detector 7 and the measured value of the thermocouple 8 to the temperature of the measured object 6 only. It consists of a temperature display and conversion section 8, etc.

The beep chip 2 of the sensor part 5 is made of a transparent material having pressure resistance and wear resistance, such as sapphire, and is fixedly held on the external protection tube 4 via a beep chip holder 9. The straight light guide 3 is made of a material such as sapphire that transmits infrared radiation of an effective wavelength, and is configured so that thermal radiation from the object to be measured 6 introduced from the beep chip 2 can be introduced into the detector 7. be. The straight light guide 3 is inserted into the axial hollow part 4a of the external protection tube 4, and the straight light guide 3 is covered and protected via a concentric light guide protection part 10.
It is designed to be protected via a concentric metal protection tube 11. The sensor part 5 is inserted into an insertion hole 13 provided in a wall or a mold 12, and is screwed and held on the wall or mold 12 via a threaded part 14 screwed into a part of the external protection tube 4. It is supposed to be done. 15 indicates the mounting plate of the detector 7, and 17 indicates the straight light guide 3.
This is the connecting part between the detector 7 and the detector 7.

Inside the detector 7, a photoelectric conversion element such as PbS, a chopper, and a preamplifier are installed, and a beep chip 2. The configuration is such that thermal radiation from the object to be measured 6 introduced through the straight light guide 3 is converted into an electrical signal, and the signal is amplified and output to the display/conversion section 8 .

A thermocouple 18 for measuring the temperature of the straight light guide 3 itself is installed inside the tip of the straight light guide 3, which becomes the hottest part of each part, and a detector 7
The temperature of the straight light guide side 3 itself can be measured in addition to the detection by the straight light guide side 3. thermocouple 18
is a display/computer with a built-in correction calculator via the compensation conductor 19.
It is connected to the conversion section 8.

The display/conversion unit 8, which has a built-in correction calculator, calculates the thermal radiation energy generated by the straight light guide 3 itself from the temperature of the 30 straight light guides measured by the thermocouple 18, and also calculates the thermal radiation energy detected by the detector 7. The structure is such that the thermal radiant energy from only the object to be measured 6 can be calculated by subtracting the thermal radiant energy of the straight light guide 3 itself from the total radiant energy detected, and the thermal radiant energy from only the object to be measured 6 after calculation processing is calculated. Convert thermal radiation energy value to temperature value and display 1. Uruyo Set-1! Soto 1. [■Display may be absolute temperature T or Celsius (Celsius) t°C, but is often converted to Celsius (t°C) and displayed.

The operation of correcting and calculating only the temperature of the object to be measured 6 by the correction calculator is performed by the following formula.

That is, in general, the relationship between the energy E detected by the detector of a monochromatic radiation thermometer and the absolute temperature T is approximately proportional to the Wien equation derived from Blank's equation, where ε is the effective emissivity and A is the Sensitivity constant proportional to optical path equivalent rate, light receiving area, etc.
c2 is a blank second constant, input is an effective wavelength, and α is a bias constant. Suppose that the straight light guide 3 is heated to an absolute temperature T', and the detector detects E' of thermal radiation energy corresponding to the temperature T'.
E' is expressed as. However, A' is straight light guide 3
is a sensitivity constant determined by the state between the straight light guide 3 and the detector.

Assuming that the temperature indicated by the radiation thermometer 1 before the rA calculation is processed by the correction calculator is T', and the total radiant energy detected by the detector 7 is E'', then E'' is E'' = E + E' = ε
It is expressed as Aexp(-)T''+α.A, input, and α are determined by the radiation thermometer and its installation condition.

In the above formula, A' in the formula for determining E' can be determined separately by experiment, so the straight light guide 3
If the temperature T' of itself can be measured separately using the thermocouple 18, the temperature of only the pair to be measured 6 can be determined using the above calculation formulas. This calculation is performed by the correction calculator in the display life converter 8, and the temperature value after the correction calculation process is
This is displayed on the display section as the temperature T of the object to be measured 6.

Note that the means for determining the temperature T of only the object to be measured 6 is not limited to the above calculation formulas, but may also be determined using a graph as shown in FIG. 2, that is, the horizontal axis shows the radiation temperature Take the displayed temperature T'' of the IW meter, create coordinates with the estimated temperature of the measured object 6 on the vertical axis, and calculate the displayed temperature T'' and 9! Display temperature of couple 18 T'+ T'2 , T'3 , T
'4, T'5, T'6, T'7. The temperature T of the ΔIII constant body 6 may be obtained from the graph 20 showing
Kamo output signal line.

and is connected to the display conversion section 8.

External protection/i? A cooling air pipe 22 for cooling the straight light guide 3 is airtightly installed inside the axial center hollow part 4a of the 4, and a cooling medium is placed between the cooling air pipe 22 and the metal protection pipe 11. A passage 23 is adapted to be formed. Reference numeral 24 indicates a cooling air supply port. In addition,
This cooling air pipe 22 is not necessarily necessary, but is provided to minimize temperature measurement errors.

Next, the operation based on the above configuration will be explained.

Thermal radiation from the object to be measured 6 is introduced into the detector 7 through the optical path of the beep chip 2° straight light guide 3, where it is converted into light through the light conversion element in the detector 7, and is Amplified via an amplifier. The output signal from the detector is inputted to the display/conversion section 8 via the output signal line 21.

On the other hand, the temperature of the light guide 3 itself measured by the thermocouple 18 is inputted via the compensation conductor 19 to the display/conversion section 8 which includes a correction calculator.

Either perform the above-mentioned calculations using the correction calculator built into the display-converter 8, or obtain the temperature of only the measured pair 6 by excluding the temperature of the light guide 3 itself from the graph shown in FIG. The temperature value is displayed on the display section as the temperature of the object to be measured 6. That is, a correction calculator is not necessary, and correction may be performed using a graph.

Furthermore, by circulating the cooling air in the cooling medium passage 23, the light guide 3 can be cooled, so that temperature measurement errors can be reduced. That is, thermal radiation is an exponential function of temperature. Therefore, when the light guide 3 is cooled to lower its temperature, the thermal radiation energy from the light guide 3 itself becomes smaller, so that the necessary correction rate increases rapidly as the temperature decreases. This is because the error is reduced, resulting in a reduction in error.

As described above, according to this embodiment, the temperature of the object to be measured 6 can be accurately measured without cooling the light kite 3 to near room temperature, and the state of the mold or mold 12 can be maintained at a high temperature. It is also effective in terms of quality L energy economy (due to savings in the degree of cooling). In addition, the rapid response, which is impossible with conventional means, makes it possible to measure rapid and minute temperature changes, which can greatly contribute to improving the quality of the plastin coating industry and the rubber industry. In addition, it is possible to introduce thermal radiation to the detector 7 through the light guide 3 through a mold with a high temperature or equipment with a high atmospheric humidity, and to prevent ambient stray light from entering from the beep chip 2, which has good wear resistance. Thermal radiation can be introduced into the detector 7.

(Second Example) FIG. 3 is an explanatory diagram showing a second example of the radiation thermometer 1 according to the present invention. The feature of this embodiment is that the light guide 3
The three light guides 3a.

3b and 3c, the first light guide 3a and the second light guide 3b are connected in series via the connector 25, and the second light guide 3b and the third light guide 3c are connected in series. They are connected to each other orthogonally via a 90 degree angle portion 26, and a 90 degree prism 27 is disposed between the second light guide 3 and the third light guide 3C. That is, the heat radiation from the object to be measured 6 is transmitted to the beep chip 2. :jSf, 2nd. light guide 3
a, 3b, a 90-degree prism 27, and a third light guide 3c before being introduced into the detector 7. Then, a thermocouple 2 is attached to the connecting tool 25 and the 90 degree angle part 26.
8.29 is provided, and the setting configuration is such that the temperature J11 of the light guide 3 in the portion where radiation is likely to be reflected and scattered can be determined. Each thermocouple 28.29 has a connecting wire 30.31
It is connected to the display/conversion section 8 including a correction calculator via.

Since the other basic configuration is the same as that shown in FIG. 1, the same members are given the same reference numerals and their explanations will be omitted.

] Even in the two-legged configuration, the same effect as in the first embodiment,
It is effective.

Note that in each of the embodiments described above, a completely solid light guide 3 has been described, but optical fibers, lenses,
Of course, the present invention can also be applied to a radiation thermometer using a prism or the like.

[Effects of the Invention] As described above, according to the present invention, the temperature of the object to be measured can be accurately measured without cooling the optical path section of the transparent solid, and the surroundings such as the mold can be maintained at a high temperature. It is effective in terms of quality and energy economy. Furthermore, it is possible to measure rapid and minute temperature changes with a fast response speed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of the radiation thermometer according to the present invention, FIG. 2 is a graph diagram for determining the temperature of an object to be measured, and FIG. 3 is a diagram showing the radiation thermometer according to the present invention. It is an explanatory view showing a second example. 3... Light guide 6... Measured object (measured object) 7... Detector 8... Display/conversion section 18 including a correction calculator...
thermocouple

Claims (4)

[Claims] (1) In a radiation thermometer configured to detect the temperature of an object to be measured by introducing thermal radiation from the object to be measured into a detector through an optical path of a transparent solid, the optical path of the transparent solid itself 1. A radiation thermometer comprising a measuring section for measuring the temperature of the body separately from the detector. (2) The radiation thermometer according to claim 1, wherein the measuring unit that measures the temperature of the optical path itself of the transparent solid is a thermocouple placed in the optical path. (3) The radiation thermometer according to claim 1, wherein the optical path of the transparent solid is configured to be coolable via a cooling medium. (4) The detector and the measurement section are connected to a correction calculation section for correcting and calculating the detected value of the detector to the temperature of only the object to be measured. The radiation thermometer according to item 1.