JPH05164626A - Temperature measuring method using thermocouple - Google Patents

Abstract

PURPOSE:To make it possible to measure temperature accurately and safely by filling the space between a material to be measured and a thermocouple with low-melting-point metal, and reducing the contact thermal resistance of the thermocouple with the material to be measured. CONSTITUTION:A measuring hole 3 is formed in the surface of a material to be measured 2 made of a metal plate material such as a copper plate for continuous casting mold. A ring-shaped low-melting-point metal 13 having, e.g. a hole part, is filled at the bottom part of the measuring hole 3. A thermocouple 1 is inserted into the hole part. Metal powder 4 such as copper powder is filled, and the upper part is fixed with fixing agent such as instantaneous bonding agent. Thus, the backlash of the material to be measured 2 and the contact thermal resistance caused by physical factors such as vibration can be suppressed to the very low values, and the accurate temperature measurement can be performed. It is not necessary to bring the tip of the thermocouple into direct contact with the material to be measured, and the life of the thermocouple can be made long.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring method using a thermocouple.

[0002]

2. Description of the Related Art Conventionally, when a thermocouple is used to measure the internal temperature of a metal plate material such as a steel plate, FIG.
The method shown in (b) is used. That is, FIG. 4 (a)
Is a measurement hole 3 having a diameter slightly larger than the outer diameter of the thermocouple 1 on the surface of the object to be measured 2 such as a metal plate material, and the thermocouple 1 is inserted in the measurement hole 3 to insert copper powder into the gap. Is an example of filling the metal powder 4 such as, and fixing the upper portion with a fixing member 5 such as an instant adhesive to measure the temperature at the temperature measuring point 6, and FIG. 4 (b) is a fixing member such as a flange. In this example, the thermocouple 1 is directly fixed to the surface of the DUT 2 using 5a.

FIG. 5 shows an example of measuring the internal temperature of a rotating body 7 such as a roll. For example, an end portion 7a of the rotating body 7 rotatably supported by a bearing 8 is attached to the end portion 7a. A round concave portion 9 is bored, and the thermocouple 1 is supported at one end thereof by a supporting member 10 such as a bracket and pressed by a pressurizing means 11 such as a spring, and then fixed by a fixing means 12 such as a flange. This is a method of directly contacting the tip with the recess 9.

[0004]

However, the above-mentioned conventional method has the following problems. That is, in the method of fixing the thermocouple 1 as shown in FIGS. 4 (a) and 4 (b), the thermocouple 1 is located immediately above the temperature measuring point 5 due to, for example, weak pressurization at the time of installation or vibration. It often happens that a space (indicated by reference numeral 3a in FIG. 4 (a)) is generated near the tip of the, and accurate measurement cannot be performed.

If the surface of the measurement hole 3 near the bottom is rough, the contact thermal resistance at the tip of the thermocouple 1 becomes extremely large, which adversely affects the measurement accuracy and makes accurate measurement impossible. Further, when the measurement of the rotating body 7 shown in FIG. 5 is performed, there is a drawback that the tip of the thermocouple 1 is worn and a measurement error occurs. It is an object of the present invention to provide a temperature measuring method using a thermocouple that solves the problems of the conventional example as described above.

[0006]

According to the present invention, when a thermocouple is brought into contact with an object to be measured and its internal temperature is measured, a low melting point metal is filled around the contact portion of the tip of the thermocouple. This is a method of measuring temperature using a thermocouple.

[0007]

[Operation] According to the present invention, the space between the object to be measured and the thermocouple is filled with the low melting point metal, so that the contact thermal resistance of the thermocouple to the object to be measured can be made extremely small. Yes, accurate and stable temperature measurement is possible.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. In the figure, the same elements as those in the conventional example are designated by the same reference numerals. [Embodiment 1] FIG. 1 is a side sectional view showing a first embodiment of the present invention, and as shown in the drawing, it has a ring shape having a hole portion 13a as shown in FIG. The low melting point metal 13 is filled. Then, the thermocouple 1 is inserted into the hole 13a, then the metal powder 4 such as copper powder is filled, and the upper portion thereof is fixed with a fixing agent 5 such as an instant adhesive.

A copper plate having a thickness of 40 mm, which is a continuous casting mold, was used as the object 2 to be measured, and three measurement holes 2 having a diameter of 10 mmφ and a depth of 30 mm were formed on the surface thereof. In addition, a ring-shaped low melting point metal 13
As for the material, Bi: 50%, Pb: 25%, Sn: 12.5%,
Cd: An alloy consisting of 12.5% and having a melting point of 61 ° C was used. The outer diameter D was 10 mmφ, the hole diameter d was 1.2 mmφ, and the height h was 10 mm. The thermocouple 1 had a sheath thermocouple with an outer diameter of 1.0 mmφ. Was used. When the mold was operated, the average value of the three thermocouples was 128 to 134 ° C (130 ° C ± 2 ° C). On the other hand, when three thermocouples were embedded in the vicinity of the measurement site by the conventional method and comparative measurement was performed, 117 to 137.
Results of 5 ° C (127.25 ± 10.25 ° C) were obtained. From this, the method of the present invention has an increase in the average value as compared with the conventional method, the contact thermal resistance is decreased, and the variation is reduced,
It was confirmed that the effect of the present invention was great, that is, two points were not affected by noise. In addition, when the above measurement site was measured by unsteady heat transfer calculation by the finite element method, 13
It was 0.6 ° C. [Embodiment 2] FIG. 3 is a side sectional view showing a second embodiment of the present invention. As shown in the drawing, a measurement hole 3 is formed in an end portion 7a of a rotating body 7 and the bottom portion thereof is formed. Ring-shaped low melting point metal 13
Is filled and fixed with the holding metal fitting 14 through the bolt 15.
Then, the thermocouple 1 is inserted from the hole 13a of the low melting point metal, and the tip thereof is slightly separated from the bottom portion and fixed.

A rotating roll was used as the rotating body 7, a ring 13 made of the same low melting point metal as that used in Example 1 was mounted, and the temperature of the end of the rotating roll was measured with a sheath thermocouple.
It was 2.5 ° C. On the other hand, the result of temperature measurement by the conventional method is 81.3-9.
Since it was 8.2 ° C., it can be seen that the variation in the method of the present invention is small. The life of the thermocouple 1 could not be measured in about 3 weeks by the conventional method, whereas according to the method of the present invention, even if 6 months passed, no trouble was caused in the continuous measurement. It can be seen that there is a sufficient effect on the wear property as well.

[0011]

As is apparent from the above description, according to the present invention, the thermocouple is filled with the low melting point metal around the tip portion of the thermocouple in the temperature measurement. The contact thermal resistance due to physical factors such as vibration or surface roughness can be kept extremely low, which allows accurate temperature measurement, and the tip of the thermocouple does not come into direct contact with the object to be measured. Therefore, it has an excellent effect that the life of the thermocouple can be extended.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a low melting point metal used in the present invention.

FIG. 3 is a side sectional view showing a second embodiment of the present invention.

FIG. 4 is a side sectional view showing a conventional example.

FIG. 5 is a side sectional view showing another conventional example.

[Explanation of symbols]

 1 Thermocouple 2 Object to be Measured 3 Measuring Hole 4 Metal Powder 5 Fixing Agent 7 Rotating Body 10 Supporting Member 13 Low Melting Point Metal 14 Holding Metal

Claims (1)

[Claims] 1. When the thermocouple is brought into contact with the object to be measured and the internal temperature thereof is measured, a low melting point metal is filled around the contact portion of the tip of the thermocouple. Temperature measurement method using a thermocouple.