JP2011173162A - Method and device for measuring length of hot long-size material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for measuring the length of a hot long-size material such as a hot steel pipe on a conveyance line, by which the top end and the tail end of a material to be measured are highly accurately detected and constraints on the installation space of equipment are also remarkably improved. <P>SOLUTION: In the method of measuring the length of the hot long-size material, by which the hot long-size material 1 is conveyed on the conveyance line 2 by taking its longitudinal direction as a conveyance direction and its length is measured by taking the hot long-size material as a material 1 to be measured, a radiation thermometer 3 for measuring the temperature of the material 1 to be measured on the conveyance line 2 is provided and the top 1a and the tail end 1b of the material 1 to be measured are detected on the basis of the temperature detected values by the radiation thermometer 3 when the material 1 to be measured is passed through the position of the radiation thermometer 3 and the length of the material 1 to be measured is calculated on the basis of the conveyed amount L of the material 1 to be measured during the time difference between a top end detected time t1 and a tail end detected time t2 of the radiation thermometer 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for measuring the length of a hot long material conveyed on a conveying line, and in particular, in the hot steel material conveying step performed in a steel pipe rolling process or the like, the length of the hot steel material. The present invention relates to a method and an apparatus for measuring the length of a hot long material suitable for use in length measurement.

  In a production line for steel materials such as steel pipes, steel bars, and thick steel plates, the length of the hot steel material being conveyed is measured. For this length measurement, the hot steel material conveyed on the conveying line with the length direction of the hot steel material as the conveying direction is measured with a hot mass detector (HMD), a photoelectric sensor, or an imaging device. It is possible to calculate the length of the hot steel material by detecting the end and calculating the amount of hot steel material transported between the tip and tail end detection timing from the timer and the roll peripheral speed of the transport roll. It has been broken.

For example, in Patent Document 1, the tip of a hot steel pipe is detected by a linear array camera, and at the same time, the rear end of the hot steel pipe is detected by a hot mass detector, and the steel pipe is detected based on these detection signals. A method for measuring the length in a non-contact manner is disclosed.
Further, in Patent Document 2, a plurality of imaging devices are arranged in a line at predetermined intervals along the conveyance direction directly above the conveyance path so that there is no gap in each field of view of the imaging device. A length-measuring device for a material to be conveyed is disclosed which measures the length of the material.

JP 60-169704 A Japanese Utility Model Publication No. 63-83609

  However, in hot steel after hot rolling, flames may be ejected from the tip or tail of the hot steel, and this flame is detected by the method of detecting the tip and tail using a hot mass detector. As a result, there is a problem that the detection of the tip of the hot steel material and the detection of the tail end may not be performed accurately. In the method of detecting the tip and tail ends with a photoelectric sensor, it is necessary to arrange a projector and a light receiver across the conveyance line. However, in a rolling line, etc. In some cases, it is difficult to secure a space for arranging both. In addition, the method using a photoelectric sensor has a problem that it cannot be applied when a steel material in which a bar (rolling tool) is inserted inside a steel pipe such as a mandrel mill is used as a material to be measured.

In addition, in the method of arranging a plurality of imaging devices as described in Patent Document 2 along the transport path, from the problem that a large number of imaging devices are required and the equipment cost is high, and the restrictions on the equipment arrangement, It may be difficult to secure the installation space.
The present invention has been made in view of such circumstances, and relates to a method and an apparatus for measuring the length of a hot long material such as a hot steel pipe on a transport line, and the tip and tail ends of the material to be measured are measured. Method and apparatus capable of detecting with high accuracy, greatly improving the restrictions on the installation space of equipment, and capable of measuring the length of a steel pipe, for example, for a hot steel pipe with a bar inserted The purpose is to provide.

In order to solve the above problems, the present inventors have used a radiation thermometer, which is often used in the steel manufacturing process, to detect the tip and tail end of a hot long material that is a material to be measured. The inventors have arrived at the idea that the problems at the time of detecting the tip and tail by the above-mentioned hot mass detector can be solved, and the present invention has been completed.
That is, the gist configuration of the present invention is as follows.
(1) A method for measuring the length of a hot long material in which the length of the hot long material is transported on a transport line and the length is measured using the hot long material as a material to be measured. A radiation thermometer for measuring the temperature of the material to be measured on the transport line, and based on a temperature detection value by the radiation thermometer when the material to be measured passes through the position of the radiation thermometer, The tip and tail ends of the material to be measured are detected, and the length of the material to be measured is determined based on the transport amount of the material to be measured during the time difference between the tip detection time t1 and the tail end detection time t2 of the radiation thermometer. A method for measuring the length of a hot long material, characterized in that it is calculated.
(2) The tip detection time t1 and the tail end detection time t2 are determined from a field occupancy ratio of a radiation thermometer obtained from a time change of a temperature detection value of the radiation thermometer. The method for measuring the length of a hot long material according to 1).
(3) As the radiation thermometer, two radiation thermometers are provided at a predetermined distance Lspan along the conveyance line, and the time t1 when the downstream radiation thermometer detects the tip of the measured material and the upstream one The length of the material to be measured is calculated based on the transport amount of the material to be measured during the time difference from the time t2 when the radiation thermometer detects the tail end of the material to be measured and the distance Lspan. The method for measuring a length of a hot long material according to (1) or (2) above.
(4) A length measuring apparatus for a hot long material that transports a hot long material on a transport line with the longitudinal direction as a transport direction, and measures the length of the hot long material as a material to be measured. A radiation thermometer for measuring the temperature of the material to be measured on the transport line, and a tip and a tail end of the material to be measured pass through the position of the radiation thermometer based on a temperature detection value by the radiation thermometer. Calculate the length of the material to be measured based on the time difference between the tip detection time and the tail edge detection time, and the transport amount of the material to be measured during the time difference. A length measuring device for measuring the length of a hot long material.
(5) The length calculation means determines the tip detection time and the tail end detection time from the visual field occupation rate of the radiation thermometer obtained from the time change of the temperature detection value of the radiation thermometer. The apparatus for measuring a length of a hot long material as described in (4) above.
(6) As the radiation thermometer, two radiation thermometers are installed at a predetermined distance Lspan along the transport line, and the length calculation means is configured to transport the measured material during the time difference. The length measuring device for a hot long material according to (4) or (5), wherein the length of the material to be measured is calculated based on the distance Lspan.

  According to the present invention, one or two radiation thermometers may be installed as detectors for the tip and tail of the hot long material that is the material to be measured, and it is easy to secure the installation space for the equipment. It is. In addition, since the tip and tail of the material to be measured are detected based on the temperature measurement result by the radiation thermometer, the tip or tail of the material to be measured is used as in the case of using a hot mass detector (HMD). The tip or tail end is not erroneously detected due to the influence of the flame coming out of it, and the tip and tail ends can be detected stably, and the length of the material to be measured can be measured with high accuracy.

It is the schematic which shows the apparatus structure of the length measuring apparatus of the hot elongate material which concerns on the 1st Embodiment of this invention. It is a graph which shows the time-dependent change of the temperature measured with a radiation thermometer. It is a graph which shows a time-dependent change of the temperature measured with a radiation thermometer, and shows the time of front-end | tip detection. It is a schematic diagram explaining the ratio (visual field occupation rate) for which a steel pipe occupies the visual field of a radiation thermometer. It is a graph which shows a time-dependent change of the temperature measured with a radiation thermometer, and shows the time of a tail end detection. It is a schematic diagram explaining the ratio (visual field occupation rate) for which a steel pipe occupies the visual field of a radiation thermometer. It is the schematic which shows the apparatus structure of the length measuring apparatus of the hot elongate material which concerns on the 2nd Embodiment of this invention. It is a graph which shows the time-dependent change of the temperature measured with a radiation thermometer.

Embodiments of the present invention are described in detail below.
FIG. 1 is a schematic diagram showing an example of the configuration of an apparatus for carrying out the method for measuring the length of a hot long material according to the first embodiment of the present invention. In addition, in this embodiment, the case where the hot long material 1 which is a to-be-measured material is a hot steel pipe (henceforth only steel pipe 1) is demonstrated as an example.
The conveyance line 2 conveys the length direction of the steel pipe 1 as the conveyance direction AS by the conveyance table which consists of several roller 2a. A radiation thermometer 3 for measuring the temperature of the steel pipe 1 is installed in the upper part of the transport line 2 and its measurement visual field is directed downward. The radiation thermometer 3 is a known non-contact thermometer that measures the temperature of the steel pipe by measuring the intensity of infrared rays and visible light emitted from the steel pipe 1.

  FIG. 2 is a graph showing a temperature measurement result when the steel pipe 1 passes through the position of the radiation thermometer 3, where the horizontal axis indicates time and the vertical axis indicates temperature. When the tip 1a of the steel pipe 1 passes directly under the radiation thermometer, the temperature measurement value suddenly rises. After that, while the steel pipe 1 is directly under the radiation thermometer, the measurement value continues to show a high value. When the tail end 1b passes directly under the radiation thermometer 3, the temperature measurement value drops abruptly.

By reading the time when there is a sudden rise in the temperature measurement value and the sudden fall in the temperature measurement value, the tip 1a and tail end 1b of the steel pipe 1 can be detected.
The conveyance roller 2 a is driven by a motor 6, and the conveyance speed is controlled by controlling the number of rotations of the motor 6 based on a speed command from the conveyance control unit 4.
Reference numeral 5 denotes calculation means for calculating the length of the steel pipe 1 based on the temperature measurement value by the radiation thermometer 3. The temperature measurement value of the radiation thermometer 3 and the speed command value from the conveyance control means 4 are input. The

  Hereinafter, a method for calculating the length of the steel pipe 1 by the calculating means 5 will be described. The calculation means 5 records the temperature measurement value by the radiation thermometer 3, and the time t1 when the temperature measurement value in FIG. 2 suddenly rises and the time t2 when the temperature measurement value suddenly falls respectively indicate the tip detection time t1. The tail end detection time t2 is recorded. And the calculation means 5 carries the conveyance amount L = v () of the steel pipe 1 between the time difference between the tip detection time t1 and the tail end detection time t2 from the speed command value v input from the transfer control means and the times t1 and t2. t2-t1) is determined. And let this conveyance amount be the length measurement value of the steel pipe 1.

Next, a preferred example of a method for determining the tip detection time t1 and the tail detection time t2 performed by the calculation means 5 will be described.
The calculation means 5 records the temperature measurement value T at each time t, which is the original data of the graph shown in FIG. And the calculation means 5 determines the front-end | tip detection time t1 and the tail end detection time t2 from the time-dependent change of a temperature measurement value.

  FIG. 3 is a graph showing in detail the time change of the temperature measurement value when passing through the tip. FIG. 4 is a schematic diagram showing the position of the tip 1a of the steel pipe 1 in the visual field 7 of the radiation thermometer 3 at points A, B, and C in FIG. 3, and FIG. 4B corresponds to point B, and FIG. 4C corresponds to point C. As shown to Fig.4 (a), when the front-end | tip 1a of the steel pipe 1 enters in the visual field of the radiation thermometer 3, a temperature measurement value will begin to raise (A point in FIG. 3). And if conveyance of the steel pipe 1 is continued, the ratio (henceforth visual field occupation rate) which the area of the steel pipe 1 occupies in the visual field 7 of a radiation thermometer as FIG.4 (a)-> (b)-> (c). Along with this, the temperature measurement value rises in the order of point A → B point → C point in FIG. 3, and when the visual field occupancy becomes 100%, the temperature measurement suddenly increases. Stop. When the visual field occupancy becomes 100% (point C), when the rapid temperature rise stops, it can be read from the waveform of the temperature change. Then, from the temperature measurement value θm when the visual field occupancy becomes 100%, the measurement temperature when the visual field occupancy is 50% is obtained by calculation. When the visual field occupation ratio is 50%, it means that the tip 1a is at the center of the visual field of the radiation thermometer. The relationship between the visual field occupation ratio in the visual field and the temperature measurement value θ measured by the occupation ratio can be expressed by the following equation (1).

  Therefore, from the waveform of temperature change, the temperature measurement value at the time when the rapid temperature rise stops is the temperature measurement value θm at the visual field occupation rate of 100%, and the value of θm and the visual field occupation rate S = 50% are described above. If it substitutes into Formula (1), temperature (theta) in 50% of visual field occupation rates can be calculated. Then, the time t1 at which the temperature when the visual field occupation ratio is 50% is read from the waveform of the temperature change shown in FIG. 3, and this is set as the tip detection time t1.

  FIG. 5 is a graph showing in detail the change over time of the temperature measurement value when passing through the tail end. FIG. 6 is a schematic diagram showing the position of the tail end 1b of the steel pipe in the visual field 7 of the radiation thermometer at points D, E, and F in FIG. 5, and FIG. 6 (b) corresponds to point E, and FIG. 6 (c) corresponds to point F. As shown in FIG. 6 (a), the visual field occupation ratio is 100% until the tail end 1b of the steel pipe 1 enters the visual field of the radiation thermometer 3. Then, when the tail end 1b enters the field of view of the radiation thermometer 3, the temperature measurement value starts to fall, and when the steel pipe 1 continues to be conveyed, the field of view is occupied as shown in FIGS. 6 (a) → (b) → (c). As the rate decreases, the temperature measurement value decreases as point D → E point → F point in FIG. 5, and when the field occupancy becomes 0%, the temperature measurement value rapidly decreases. Stops. When the visual field occupancy ratio starts to decrease from 100% (point D in FIG. 5), it is a time when a rapid temperature decrease starts, so that it can be read from the waveform of the temperature change. Then, from the temperature measurement value θm when the visual field occupancy starts to decrease from 100%, a measurement temperature when the visual field occupancy is 50% is obtained by calculation. When the visual field occupation ratio is 50%, it means that the tail end 1b is at the center of the visual field of the radiation thermometer. Since the relationship between the visual field occupation ratio in the visual field and the temperature measurement value θ measured by the occupation ratio can be expressed by the above equation (1), the temperature measurement value at the time when the temperature starts to decrease can be represented by the visual field. As with the temperature measurement value θm at the occupation rate of 100%, the temperature at the visual field occupation rate of 50% is obtained in the same manner as when the tip detection time t1 is obtained, and the time t2 when this temperature is reached is read from the waveform of the temperature change. This is the tail end detection time t2.

  In the example described above, when the tip 1a and the tail end 1b are positioned at the center of the field of view of the radiation thermometer 3, the tip detection time t1 and the tail end detection time t2 are set to 50%. However, for example, the tail end detection time t1 may be a time with a visual field occupation rate of 30%, and the tip detection time t2 may be a time with a visual field occupation rate of 70%. The sum of the visual field occupancy value for calculating the tip detection time t1 and the visual field occupancy value for calculating the tail detection time t2 may be 100%.

  Next, a second embodiment of the present invention will be described. FIG. 7 is a schematic view showing an example of a device configuration for carrying out the method for measuring the length of a hot long material according to the second embodiment of the present invention. In the present embodiment, a case where the hot long material as the material to be measured is the hot steel pipe 1 (hereinafter simply referred to as the steel pipe 1) will be described as an example. Further, the same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The second embodiment is different from the first embodiment in that two radiation thermometers are provided on the transport line. That is, the radiation thermometer 3a and the radiation thermometer 3b are provided along the transport line 2, and the distance between them is a known value Lspan. Then, the tip 1a of the steel pipe 1 is detected by the downstream radiation thermometer 3a, and the tail end 1b of the steel pipe 1 is detected by the upstream radiation thermometer 3b. In FIG. 7, the case where the tail end 1b of the steel pipe 1 exists in the position of the radiation thermometer 3b of the downstream is shown.

FIG. 8 shows the change over time of the temperature measurement values of the radiation thermometer 3a and the radiation thermometer 3b when the steel pipe 1 passes through the apparatus shown in FIG. 7, and (a) shows the length Lpipe of the steel pipe 1. Is longer than the distance Lspan between the two radiation thermometers 3a and 3b, and (b) shows the case where the length Lpipe of the steel pipe 1 is shorter than the distance Lspan between the two radiation thermometers 3a and 3b.
Since the radiation thermometer 3b is upstream of the radiation thermometer 3a by the distance Lspan, the temperature measurement value is measured before the measurement value of the radiation thermometer 3a by the conveyance time of Lspan. stand up.

  The calculating means 5 records the tip detection time t1 by the radiation thermometer 3a and the tail end detection time t2 by the radiation thermometer 3b. The method for determining the tip detection time t1 and the tail detection time t2 is performed in the same manner as in the first embodiment. As shown in FIG. 8A, when the tip detection time t1 by the radiation thermometer 3a is earlier than the tail detection time t2 by the radiation thermometer 3b, that is, when t1 <t2, the result is shown in FIG. Thus, since the length Lpipe of the steel pipe 1 is longer than Lspan, the length Lpipe of the steel pipe 1 is obtained by adding the transport amount L during the time difference between t1 and t2 to Lspan. Conversely, as shown in FIG. 8B, when the tip detection time t1 by the radiation thermometer 3a is later than the tail end detection time t2 by the radiation thermometer 3b, that is, when t1> t2, the steel pipe Since the length Lpipe of 1 is shorter than Lspan, the length Lpipe of the steel pipe 1 is obtained by subtracting the conveyance amount L during the time difference between t1 and t2 from Lspan. When the tip detection time t1 by the radiation thermometer 3a is coincident with the tail end detection time t2 by the radiation thermometer 3b, that is, when t1 = t2, the length Lpipe = Lspan of the steel pipe 1 is assumed. Become.

Therefore, from the speed command value v from the conveyance control means and the time difference between time t1 and time t2, the conveyance amount L = v · (t2−t1) between the time differences is obtained, and the length of the steel pipe 1 is obtained from the following equation. Lpipe can be calculated.
Lpipe = Lspan + L
In the second embodiment of the present invention, the time difference between t1 and t2 is smaller than in the first embodiment, and thus the transport amount of the steel pipe 1 calculated during this time is smaller. And the length of the amount by which the conveyance amount is reduced can use the value of the distance Lspan between the two radiation thermometers 3a and 3b, which is a known value. Since the time difference between t1 and t2 is small and the conveyance amount therebetween is also small, even if there is a slight deviation between the speed command v and the actual conveyance speed, the error regarding the conveyance amount is small, and the first The steel pipe length can be measured with higher precision than in the embodiment.

As an example of the present invention, the length measuring device for a hot long material shown in the second embodiment described above is installed on the exit side of a mandrel mill of a seamless pipe production line, and a length of 4140 mm to which a bar is inserted. The length of a 8000 mm seamless steel pipe was measured.
As a comparative example, length measurement was performed with an existing length measurement device using a hot mass detector (HMD) instead of the radiation thermometers 3a and 3b in the second embodiment described above.

About the steel pipe after measurement, it measured using the measure, calculated | required exact length (measured value), and made the measurement accuracy the value which subtracted the measured value from the measured value in the example of this invention or a comparative example.
Table 1 shows the N number and the standard deviation σ for each length of the measurement accuracy data. In the example of the present invention, the standard deviation is much smaller than that of the comparative example, which also shows that the measurement accuracy is high.

  The present invention is not limited to the measurement of the length of a hot steel pipe, but can be widely applied to the measurement of the length of a hot long material other than a steel pipe such as a steel plate or a steel bar. In addition, the length can be measured even in the case of a steel pipe into which a bar is inserted, and it is also possible to apply to a conveyance line in a mandrel mill.

1 Steel pipe (hot long material, material to be measured)
1a Steel pipe tip 1b Steel pipe tail end 2 Transport line 3 Radiation thermometer 3a Downstream radiation thermometer 3b Upstream radiation thermometer 4 Transport control means 5 Calculation means 6 Motor 7 Field of view of radiation thermometer

Claims (6)

In the method for measuring the length of a hot long material, the length of the hot long material is transported on the transport line as the transport direction, and the length of the hot long material is measured as the material to be measured.
A radiation thermometer for measuring the temperature of the material to be measured on the transport line is provided,
Based on the temperature detected by the radiation thermometer when the material to be measured passes through the position of the radiation thermometer, the tip and tail ends of the material to be measured are detected, and the tip detection time t1 of the radiation thermometer The length measurement method of the hot long material characterized by calculating the length of the said to-be-measured material based on the conveyance amount of the to-be-measured material between the time difference of the time and tail end detection time t2.   2. The front end detection time t1 and the tail end detection time t2 are determined from a field occupancy ratio of a radiation thermometer obtained from a time change of a temperature detection value of the radiation thermometer. Method for measuring the length of hot long materials. As the radiation thermometer, two radiation thermometers are provided at a predetermined distance Lspan along the transport line,
The conveyance amount of the material to be measured between the time difference between the time t1 when the downstream radiation thermometer detects the tip of the material to be measured and the time t2 when the upstream radiation thermometer detects the tail of the material to be measured. The length measurement method of the hot long material according to claim 1, wherein the length of the material to be measured is calculated based on the distance Lspan. A hot long material length measuring device that transports a hot long material on a transport line with its longitudinal direction as the transport direction, and measures the length of the hot long material as a material to be measured. ,
A radiation thermometer for measuring the temperature of the material to be measured on the conveying line;
Based on the temperature detection value by the radiation thermometer, the time at which the tip and tail ends of the material to be measured have passed the position of the radiation thermometer are obtained as the tip detection time and the tail detection time, respectively. Length measurement means for calculating a length of a hot material having a length calculation means for calculating a length of the material to be measured based on a time difference from a detection time and a conveyance amount of the material to be measured during the time difference apparatus.   The length calculation unit determines the tip detection time and the tail detection time from a visual field occupation ratio of the radiation thermometer obtained from a time change of a temperature detection value of the radiation thermometer. 4. A length measuring apparatus for hot long materials according to 4. As the radiation thermometer, two radiation thermometers are installed at a predetermined distance Lspan along the conveyance line,
The hot length according to claim 4 or 5, wherein the length calculation means calculates the length of the material to be measured based on the conveyance amount of the material to be measured during the time difference and the distance Lspan. Material length measuring device.

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