JPH0534203A - Temperature measurement method for high temperature objects - Google Patents

Abstract

PURPOSE:To make it possible to measure the accurate temperature at the tip part of a moving high temperature body by making the rise time of a radiation thermometer quick. CONSTITUTION:A steel strip 2 is mounted on conveying rollers 1. The steel strip 2 can be moved. A radiation thermometer 3 whose light receiving part 3a faces downward is provided over the temperature-measurement starting position of the steel strip 2. A heater 5, which faces the light receiving part 3a with the gap between the conveying rollers 1 in-between, is provided under the light receiving part 3a. A measurement-start sensor 6 is provided at the gap between the conveying rollers 1 for which the radiation thermometer 3 is provided A preliminary light-measurement-start sensor 7 is provided at the gap between the conveying rollers 1 at the front side from the gap between the conveying rollers l for which the measurement-start sensor 6 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a hot rolling process of a metallic material and the like, and is a method for sequentially measuring the temperature of a high temperature object to be conveyed such as a material to be rolled by using a radiation thermometer. Regarding

[0002]

2. Description of the Related Art In the hot rolling process, the radiant energy of the material to be rolled is sequentially radiated in order to control the quality control and the decision of the rolling schedule for the scale etc. which occur due to the temperature. The temperature of the material to be rolled, which is the high-temperature object, is measured by inputting it from the light receiving part of the thermometer and using the radiation thermometer.

The radiation thermometer converts radiant energy into an electrical temperature signal through a photoelectric conversion element, supplies the temperature signal to a temperature determination circuit, and calculates the temperature of the high-temperature substance by calculation by the temperature determination circuit. Has been decided. The radiation thermometer is used for the temperature measurement because it is difficult to measure with the contact type because the object to be measured is moving at high temperature and at high speed.

[0004]

However, in the radiation thermometer, the rise response of the photoelectric conversion element and the temperature determining circuit takes some time. For example, when the rise response of the thermometer using a Si photocell that is generally used for high temperature is obtained for the photoelectric conversion element of the radiation temperature measuring device, the result shown in FIG. 3 is obtained.
In FIG. 3, f indicates the position where the high temperature object enters the visual field of the thermometer, and a indicates the temperature measured by the thermometer. Also, the measured temperature of the high temperature object is about 1000 ° C.
Is.

As can be seen from the above, a radiation thermometer can obtain a response of 95% or more for a high temperature object of 1000 ° C.
It took 0.6 seconds, and it took more than 0.7 seconds to get a response of about 1000 ° C. However, for example, a steel strip, which is an object to be measured in a hot continuous rolling process of steel, passes under the thermometer for about 7 to 10 m during the response time at the rising. That is, the temperature is not correctly measured at a portion of about 10 m from the tip of the steel strip, and the portion is cut off regardless of whether it is good or bad, so quality control and control of plate thickness etc. There is a problem in ensuring accuracy.

A method of varying the response time of the radiation thermometer is described in Japanese Patent Laid-Open No. 62-145124, but this does not speed up the response speed of the radiation thermometer but rather the response speed. Is variable in the slow direction. The present invention has been made in view of the above problems, and an object thereof is to shorten the rise time of a radiation thermometer and enable accurate temperature measurement from the tip of a moving high-temperature object. ..

[0007]

In order to achieve the above object, a method for measuring a high temperature object according to the present invention is a method for measuring the temperature of a high temperature object to be conveyed using a radiation thermometer,
Before the hot object enters the field of view of the receiver of the radiation thermometer,
It is characterized in that radiant energy close to the measured temperature of the high-temperature object is incident on the light receiving part of the radiation thermometer.

[0008]

Before the moving hot object reaches the field of view of the radiation thermometer, radiant energy equivalent to the predicted measured temperature of the hot object is input to the light receiving portion of the thermometer. As a result, the photoelectric conversion element of the radiation thermometer and the temperature determination circuit are activated before the high-temperature object reaches the light receiving unit, that is, before the measurement is started, and the radiation thermometer is in a state sufficiently aged up.

When the tip of the high-temperature object reaches the field of view of the radiation thermometer, the pre-input is cut off, and only the radiant energy of the high-temperature object is made incident on the light-receiving portion of the thermometer, and the high-temperature object Start temperature measurement of. At this time, since the radiation thermometer is sufficiently aged up, at the start of temperature measurement of the high temperature object, the temperature rises in a short time following the deviation from the initially predicted temperature, and the accurate temperature is measured at the tip of the high temperature object. Measured from the department.

[0010]

Embodiments of the present invention will be described with reference to the drawings.
The present embodiment is an example applied to the temperature measurement of a conveyed steel strip in hot rolling. First, the configuration will be described.
As shown in FIG. 2, the steel strip 2 is placed on the conveying roller 1 which is horizontally arranged at a predetermined interval, and the steel strip 2 can be moved horizontally by the rotation of the conveying roller 1. ..

Above the temperature measurement start position of the moving steel strip 2, the radiation thermometer 3 with the light receiving portion 3a facing downward.
Is installed. The radiation thermometer 3 includes a photoelectric conversion element and a temperature determination circuit (not shown), converts the radiant energy input from the light receiving unit 3a into an electrical temperature signal by the photoelectric conversion element, and converts the temperature signal into the temperature determination circuit. Supply. The temperature determination circuit receives the temperature signal and performs calculation to determine the temperature of the steel strip 2 which is the high temperature object, and the controller 4
Supply to.

Further, below the light receiving portion 3a of the radiation thermometer 3, there is provided a heater 5 which is a heater facing the light receiving portion 3a with a radiation surface facing the light receiving portion 3a. And operates according to an operation signal from the controller 4. Further, in the gap between the transport rollers 1 on which the radiation thermometer 3 is installed, a measurement start sensor 6 including a pair of optical sensors facing each other vertically so as to sandwich the gap.
Is installed, the passage of the steel strip 2 is detected by the sensor 6, and the detection signal is supplied to the controller 4.

Further, the passage of the steel strip 2 is vertically opposed to the gap between the transport rollers 1 on the front side of the gap between the transport rollers 6 in which the measurement start sensor 6 is arranged. A pre-lighting start sensor 7 including a pair of optical sensors for detecting prior to 6 is installed, and the steel strip 1
A passing detection signal is supplied to the controller 4. The controller 4 is connected to a display device, a recorder, etc. not shown.

In the apparatus having the above-mentioned structure, the steel strip 2 is fed to the transport roller 1 and moves from the right side to the left side in FIG. The conveyed steel strip 2 is first detected by the pre-light start sensor 7 and the signal thereof is supplied to the controller 4. Then, the controller 4 sends an operation signal to the heater 5 to heat the heater 5 and cause the radiant energy to enter the light receiving portion 3a of the radiation thermometer 3 facing the upper side. At this time, a temperature signal estimated from the measured temperature of the steel strip 2 in the past is supplied from the controller 4 to the heater 5, and the heating temperature of the heater 5 radiates radiant energy close to the temperature of the steel strip 2 to be measured.

The heating temperature of the heater 5 may be a constant value when the range of temperature fluctuation of the object to be measured is small or when the required level for rising response is low.
In hot rolling, the steel strip 2 as the object to be measured is conveyed at a substantially constant temperature, and the range of temperature fluctuation is relatively small. Therefore, a constant temperature signal is sent to the heater 5. Good. Further, when the range of temperature variation due to steel type or the like is large, the reached temperature may be predicted by supplying the information to the controller 4 in advance, and the temperature signal based on the predicted value may be sent to the heater 5. ..

The radiation light from the heater 5 causes the radiation thermometer 3 to sufficiently rise before the temperature measurement is started, and then the steel strip 2 enters the field of view of the radiation thermometer 3. At this time,
The radiant energy from the heater 5 is blocked by the steel strip 2 and the input to the thermometer 3 is cut. Further, the measurement start sensor 3 detects the passage of the steel strip 2 and supplies the detection signal to the controller 4. After a predetermined time has passed, the controller 4 starts measuring the temperature of the steel strip 2 and transmits a stop signal to the heater 5 to stop heating from the heater 5.

Here, the predetermined time is the response time of the thermometer to the deviation between the pre-incidence light from the heater 5 and the measured temperature from the steel strip 2, and the pre-incidence light and the temperature of the steel strip 2 are Because of the closeness, the response time is extremely short and the predetermined time is extremely short as compared with the case where the pre-incident light is not input in advance as in the conventional case. Therefore, it is possible to measure the temperature accurately from the tip of the steel strip 2.

When the operation of the above measurement was conducted by using the steel strip 2 having a high temperature of 1000 ° C., the results shown in FIG. 2 were obtained. In FIG. 2, f is the position where the measurement start sensor 6 detects the tip of the steel strip 2, a is the measured value supplied from the thermometer, and b is the measurement start indicating the passage of the steel strip 2. The signal from the sensor 6 is shown.

As can be seen from FIG. 2, the measurement start position f
When is the arrival point of the steel strip 2 at the thermometer, after about 20 msec,
It can be seen that the value measured by the thermometer is set to the temperature of the steel strip 2. That is, the temperature of the steel strip can be accurately measured from a position 200 to 300 mm from the tip of the steel strip 2. Therefore, steel strip 2
The accuracy of the estimation of the presence or absence of scale due to the temperature of the tip portion is improved, and the portion that was conventionally unconditionally cut off for quality assurance can be taken in as a good product, and the yield is improved.

In this embodiment, the example of measuring the steel strip in the hot rolling process is shown, but it can be used when it is desired to measure accurately from the tip of a high temperature object moving at high speed.

[0021]

As described above, according to the method for measuring a high temperature object of the present invention, in the measurement of a moving object which is not suitable for contact type measurement at high temperature, the radiation used for the measurement before the measurement is started. By starting up the thermometer, the rise response time for the measurement of the high temperature object can be shortened, so that the correct temperature can be measured from the tip of the high temperature object that first enters the visual field of the radiation thermometer.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an apparatus of a temperature measuring method for a high temperature object according to an embodiment of the present invention.

FIG. 2 is a diagram showing a rising state of a measured temperature in an example according to the present invention.

FIG. 3 is a diagram showing a rising state of measured temperature in a conventional example.

[Explanation of symbols]

 2 Steel strip (high-temperature object) 3 Radiation thermometer 4 Controller 5 Heater (radiation energy generation means) 6, 7 Sensor

Claims (1)

Claim: What is claimed is: 1. A method for measuring the temperature of a hot object conveyed by using a radiation thermometer, wherein the high temperature object before the hot object enters the field of view of the light receiving part of the radiation thermometer. A method for measuring the temperature of a high-temperature object, characterized in that radiant energy close to the measured temperature of the object is incident on a light receiving portion of a radiation thermometer.