JPH0814513B2 - How to measure the temperature of a metal strip - Google Patents

Description

The present invention relates to a metal strip temperature measuring method capable of accurately measuring the temperature of a metal strip with a simple means.

<Prior Art> In a continuous annealing furnace for metal strips or the like, heat treatment is performed to obtain predetermined material characteristics. In such a heat treatment, it is important to grasp the accurate temperature of the metal strip, and generally, a radiation thermometer having a fast response is used for continuous non-contact temperature measurement.

On the other hand, for measuring the temperature of the metal strip in a place where the radiation thermometer cannot be used, as shown in FIG. 5, the temperature measuring roll 5 having the thermocouple 7 embedded in the outer cylinder 2 of the hollow roll is used. There is a case where a temperature-measuring roll system is used in which the metal strip 1 is brought into contact with the metal strip 1 and the signal of the thermocouple 7 is output to the indicator or the recorder 6 via the slip ring 4. In the figure, 3 is a bearing.

The temperature measuring roll 5 may be used for correcting the emissivity of a radiation thermometer (see Japanese Patent Application No. 62-326716).

<Problems to be Solved by the Invention> However, when the temperature of the metal strip 1 is measured using the temperature measuring roll 5 having the thermocouple 7 embedded therein, if the shape of the metal strip 1 is bad, As shown in the figure, the metal strip 1 and the temperature measuring roll 5 may not always be in close contact with each other at the temperature measuring point.

In this case, in the conventional temperature measuring roll, since the embedded thermocouple 7 is one, whether the thermocouple 7 is correctly measuring the temperature of the metal strip 1 or the temperature of the metal strip 1 is the same. There is a problem that it cannot be determined whether or not the temperature of the temperature measuring roll 5 itself is being measured.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for measuring the temperature of a metal strip, which can advantageously solve the above-mentioned problems of the prior art.

<Means for Solving the Problems> The present invention provides a method for measuring the temperature of a metal strip by contacting a metal strip with a temperature-measuring roll having a plurality of thermocouples attached in the lengthwise direction of the roll inside a hollow roll. If the variation of the output signals of the plurality of thermocouples is within a predetermined range, the output signal of any one of the thermocouples is adopted, and the variation of the output signals of the plurality of thermocouples is outside the predetermined range. The maximum value of the thermocouple output signal is adopted when the ambient temperature is higher than the metal strip temperature, and the maximum value of the thermocouple output signal is adopted when the ambient temperature is lower than the metal strip temperature. And a method for measuring the temperature of a metal strip.

<Function> A location where it can be determined that the temperature measuring roll and the metal strip are in contact by comparing the signals of each thermocouple with each other using a temperature measuring roll in which multiple thermocouples are installed in the length direction of the hollow roll The temperature of the metal strip can be accurately measured by determining that the thermocouple signal close to is the metal strip temperature.

<Example> An example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of a temperature measuring roll according to the present invention, showing a state in which a metal strip is in close contact with the temperature measuring roll.

In FIG. 1, 1 is a metal strip such as a steel strip, which is subjected to a predetermined heat treatment in a continuous annealing furnace. 5
Is a temperature measuring roll in which a plurality of thermocouples are embedded at intervals in the inner shell length direction of the hollow outer cylinder 2. In this example, five thermocouples 7a to 7e are provided. Thermocouple 7a ~
The detection signal from 7e is output to the indicator or the recorder 6 via the slip ring 4.

Then, as shown in FIG. 1, if the temperature measuring roll 5 and the metal strip 1 are almost completely adhered to each other, the thermocouples 7a to 7e
The signal of has a small variation and shows almost the same value. Therefore,
As the temperature of the metal strip 1, the signal of 7c arranged at the center can be used.

This will be described in a specific example in which five thermocouples 7a to 7e are installed inside the metal strip 1 at intervals of 100 mm with respect to the width of the metal strip 1 of 600 mm.

When the temperature-measuring roll 5 and the metal strip 1 are almost completely in contact with each other, as shown in FIG. 2, when the ambient temperature of the continuous annealing furnace is 750 ° C., the signals of the thermocouples 7a to 7e vary in width. Showed almost the same value within 10 ° C. Therefore, the temperature of the metal strip 1 can use the centrally located signal of 7c, as described above, the value of which is 688 ° C. When the ambient temperature was higher than that of the metal strip (when heated), the temperature of the metal strip was within + 5 ° C, and conversely, when it was low (when cooled), it was within -5 ° C.

However, if the metal strip 1 is not in close contact with the temperature measuring roll 5 as shown in FIG. 3, as shown in FIG.
The signals of the thermocouple 7 have large variations.

In this case, the temperature to be adopted changes depending on whether the metal strip 1 acts to give heat to the temperature measuring roll 5 or acts to remove heat from the temperature measuring roll 5.
In the case of the temperature measuring roll 5 installed in a place where the temperature of the metal strip 1 is considered to be higher than the ambient temperature, the temperature showing the maximum temperature is adopted, and conversely the temperature of the metal strip 1 is lower than the ambient temperature. If it is placed in a place that is considered to be, use the thermocouple signal indicating the lowest temperature. For example,
In the example shown in FIG. 4, the ambient temperature is 750 ° C,
Since this is the case when the temperature is higher than the metal strip temperature, the signal of 7a, which is the minimum value among the outputs of the thermocouples 7a to 7e, is adopted as the metal strip temperature. In the above specific example, if the variation of the signals of the thermocouples 7a to 7e is within 50 ° C., the metal strip 1 is used when the maximum value or the minimum value is adopted.
The temperature error between and is about ± 15 ℃.

In the above specific example, five thermocouples were installed for the strip width of the metal strip of 600 mm. Normally, thermocouples to be embedded in the temperature measuring roll are arranged at 100 mm intervals in consideration of the meandering of the strip. Therefore, it is better to be able to cover a width with a margin of 100 mm from the maximum width of the object to be measured. Then, for measuring the temperature of the metal strip, a thermocouple arranged inside the width of the strip passing over the temperature measuring roll at the time of measurement is used. Thermocouples out of the width of the metal strip are strongly affected by ambient temperature and are not suitable for measuring the temperature of the metal strip. In order to improve the accuracy, it is effective to narrow the interval between the thermocouples to increase the number or to increase the number in the circumferential direction of the temperature measuring roll.

Although the above embodiments have been described with respect to the continuous heat treatment furnace, it is needless to say that they can be applied to a line where the temperature measuring roll can be easily used.

<Effects of the Invention> As described above, according to the present invention, the temperature of the metal strip can be accurately measured by a simple means, which has an excellent effect.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a temperature measuring roll according to the present invention, showing a state in which a metal strip is in close contact with the temperature measuring roll. FIG. 2 shows a concrete example in which the temperature of the metal strip is measured in the state of FIG. FIG. 3 is a sectional view of an embodiment of the temperature measuring roll according to the present invention, showing a state in which a part of the metal strip is floating from the temperature measuring roll. FIG. 4 shows a concrete example in which the temperature of the metal strip is measured in the state of FIG. FIG. 5 (1) is a sectional view of a conventional temperature measuring roll, showing a state in which a metal strip is in close contact with the temperature measuring roll, and FIG. 5 (2) is a sectional view taken along line I-I of FIG. 5 (1). It is a figure. FIG. 6 is a cross-sectional view of a conventional temperature measuring roll, showing a state in which a part of the metal strip is floating from the temperature measuring roll. 1 ... Metal strip, 2 ... Outer cylinder, 3 ... Bearing, 4 ...
… Coupling, 5 …… Temperature measuring roll, 6 …… Indicator or recorder, 7a ～ 7e …… Thermocouple.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-21028 (JP, A) JP-A-58-80703 (JP, A)

Claims (1)

[Claims] 1. A method for measuring the temperature of a metal strip by contacting a metal strip with a temperature-measuring roll having a plurality of thermocouples mounted in a hollow roll in the lengthwise direction of the roll cylinder. If the variation of the output signal is within the predetermined range, use the output signal of any one thermocouple,
When the variation of the output signals of the plurality of thermocouples is outside the predetermined range and the ambient temperature is higher than the metal strip temperature, the minimum value of the output signals of the thermocouple is adopted, and the ambient temperature is higher than the metal strip temperature. When the temperature is low, the maximum value of the output signal of the thermocouple is adopted.