KR101921077B1 - Apparatus and method for measuring temperature - Google Patents

Abstract

The present invention provides a temperature measuring apparatus and a temperature measuring method for generating a sound wave on an object to be processed, measuring a discharge wave emitted from the object to be processed, and calculating the temperature of the object to be processed using the measured wave. According to the present invention, the temperature of a high-temperature object to be processed can be accurately measured by using a sound wave.

Description

[0001] Apparatus and method for measuring temperature [0002]

The present invention relates to a temperature measuring apparatus and a temperature measuring method, and more particularly, to a temperature measuring apparatus and a temperature measuring method for measuring the internal temperature of a slab produced in a steel mill in a non-contact manner.

When a steel plate is manufactured at a steel mill, the slab is heated at a high temperature in the hot-rolling furnace and rolled in the next process. At this time, the average temperature inside the slab is an important process factor. That is, when the actual temperature of the slab is higher than the calculated temperature, it is unnecessarily heated so that scale generation increases and fuel use increases. Conversely, when the actual temperature is lower than the calculated temperature, a problem of the shipping and material occurs. Therefore, the accuracy of the calculated temperature is required, and the model must be optimized to reproduce the measured temperature at the calculated temperature.

A conventional method of measuring the surface temperature of a high temperature object uses a pyrometer which utilizes that the radiant energy generated from a high temperature object is expressed as a function of temperature. That is, the intensity of radiant energy is measured in a high temperature object and converted to the surface temperature of the object. However, in the case of a heating furnace, it is difficult to measure the temperature at an ambient temperature of 1200 ° C. or more, and temperature measurement can be performed immediately after leaving the heating furnace. However, in the method of measuring the temperature using the conventional pyrometer at the stage just after the heating, only the surface temperature can be measured, and the accuracy of the measurement is limited due to the influence of the surface scale and the like.

Therefore, at present, there is no proper means for measuring the internal temperature of the slab, and feedback control of the slab heating condition in the heating furnace is impossible. To compensate for this, whenever a problem occurs acyclic in the furnace, the test slab with TC (thermo-couple) inserted is used to measure the temperature change of the slab according to the heating condition, and the calculation condition is modified based on this. However, this method requires a lot of time and effort, has to be stopped and carried out, and has a disadvantage in that real-time correction is impossible. Therefore, it is still difficult to optimize the heating temperature of the furnace by using the slab internal temperature measurement in real time.

KR 10-0698740 B1 KR 10-2003-0055372 A

The present invention provides a temperature measuring apparatus and method that can measure the internal temperature of a slab immediately after a heating furnace in a noncontact manner.

The present invention provides a temperature measurement apparatus and method that can measure the internal temperature of a slab on-line in a manufacturing process.

The present invention provides an apparatus and method for measuring a slab temperature capable of controlling heating conditions of a heating furnace in real time.

A temperature measuring apparatus according to an embodiment of the present invention includes an acoustic generator capable of generating a sound wave on an object to be processed, a wave measuring device capable of measuring a discharge wave emitted from the object to be processed, and a wave measuring device And a temperature calculator for calculating the temperature of the object to be processed.

The sound generator may generate at least one of an audible sound wave and an ultrasonic wave in the object to be processed, and the wave detector may measure a frequency of the emission wave. The emission wave may include a standing wave formed by reciprocating the inside of the object to be processed, and the emission wave may include a longitudinal wave emitted to the outside of the object to be processed. The temperature of the object to be treated may include the internal temperature of the object to be treated. The sound generator may generate a sound wave to be applied to the object to be processed, or may apply an impact to the object to cause a sound wave in the object to be processed.

The temperature measuring apparatus may further include a thickness measuring device for measuring the thickness of the object to be processed. The temperature calculation unit may include a transmission unit receiving the frequency data from the wave measuring device or receiving the frequency data and the thickness data from the thickness measuring device, a storage unit for storing predetermined data related to the speed and thickness of the sound wave of the subject, And a calculation unit for calculating the temperature of the object to be processed by using the frequency data and the setting data.

A method for measuring a temperature according to an embodiment of the present invention is a method for measuring a temperature of a substance to be treated, comprising the steps of generating a sound wave on a substance to be treated, measuring a release wave emitted from the substance to be treated, .

The step of measuring the emission wave may include the step of measuring the frequency from the emission wave, and the step of calculating the temperature may include the step of calculating the internal temperature of the object using the frequency. The emission wave may include a standing wave formed by reciprocating the inside of the object to be processed, and the process of calculating the temperature may include a process of calculating the temperature using the frequency, sound wave speed, and thickness of the object to be processed .

The temperature measuring method may further include a step of measuring the thickness of the object to be processed. Calculating the velocity correlation coefficients a1 and b1 by using the inverse relationship between the sound wave velocity V and the temperature T of the object to be processed and calculating the velocity correlation coefficients a1 and b1 before the process of calculating the temperature, can do. The temperature calculating step calculates the temperature T by using the following equation using the frequency (Fn) data, the first setting data of the speed correlation coefficients (a1, b1), and the thickness (L) Can be calculated. Where n is a natural number of 1, 2, 3 ....

n is a natural number of 1, 2, 3 ...

Here, with the frequency Fn data, the frequency at which n is 1 can be selected, or the frequency at which the signal is most apparent among the frequencies of the emission wave can be selected.

Also, before calculating the temperature, the speed correlation coefficients (a1, b1) are calculated using the inverse relationship between the sound wave velocity (V) and the temperature (T) of the object to be processed, And calculating the thickness correlation coefficients a2 and b2 using the proportional relationship between the thickness L of the object to be processed and the temperature T and storing the thickness correlation coefficients a2 and b2 as the second setting data. The process of calculating the temperature is performed by using the frequency setting data of the frequency Fn, the first setting data of the speed correlation coefficients a1 and b1 and the second setting data of the thickness correlation coefficients a2 and b2, (T) can be calculated. Where n is a natural number of 1, 2, 3 ....

Here, with the frequency Fn data, the frequency at which n is 1 can be selected, or the frequency at which the signal is most apparent among the frequencies of the emission wave can be selected.

Meanwhile, the process of calculating the temperature includes a process of calculating a plurality of temperature values using angular frequency (Fn) data according to different n values and n values, and a process of calculating an average value from the plurality of temperature values can do. The process of calculating the temperature includes a process of selecting the frequency at which n is 1 as the fundamental frequency, a process of converting the frequency at the time when n exceeds 1 into the frequency at the time when n is 1, Calculating an average value of the frequency and the auxiliary frequency to obtain average frequency data, and calculating the temperature of the subject using the average frequency data.

The object to be temperature-measured may include a slab discharged from the hot-rolling furnace.

According to the embodiments of the present invention, the temperature of the object to be treated at a high temperature can be accurately measured using sound waves. That is, the internal temperature of the object (slab) can be measured in a non-contact manner. In addition, the internal temperature of the slab can be accurately measured in real time on-line in the operating process immediately after being discharged from the heating furnace.

In addition, the heating conditions of the slab in the heating furnace can be feedback-controlled in real time using the measured temperature of the slab. That is, the temperature rise of the slab in the heating furnace can be measured in real time and feedback control can be performed to achieve the optimum heating condition. This makes it possible to secure the surface quality of the slab and to minimize the amount of heat that is heated.

1 is a view schematically showing a structure of a temperature measuring apparatus according to an embodiment of the present invention.
2 is a diagram conceptually showing progress of a sound wave in order to explain an embodiment of the present invention.
3 is a graph illustrating changes in sound wave velocity according to an embodiment of the present invention.
FIG. 4 is a graph showing a thickness variation according to an embodiment of the present invention. FIG.
5 is a wave spectrum graph according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, but may be embodied in various forms. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. In the meantime, the drawings may be exaggerated to illustrate embodiments of the present invention, wherein like reference numerals refer to like elements throughout.

Hereinafter, embodiments of the present invention will be described in detail with reference to a slab of a steelworks. However, the present invention can also be applied to the measurement of the internal temperature of various objects to be processed.

1 is a view schematically showing a structure of a temperature measuring apparatus according to an embodiment of the present invention. First, a temperature measuring apparatus according to an embodiment of the present invention will be described with reference to FIG.

The temperature measuring apparatus according to the embodiment of the present invention includes an acoustic generator 10 capable of generating a sound wave on an object S, a wave measuring device 20 capable of measuring a discharge wave emitted from the object to be processed, And a temperature calculator (30) for calculating the temperature of the object to be processed by using the measured wave from the measuring machine. Further, the temperature measuring apparatus may further include a thickness measuring device (not shown) for measuring the thickness of the object to be processed.

Here, a sound wave means a sound wave in a broad sense, and includes, for example, a sound wave or an ultrasonic wave of a human audible range. This sound wave is caused to the object to be processed, and the emission wave emitted when the sound wave propagates in the object to be processed is externally measured. The temperature of the inside of the object to be treated is calculated using the measured discharge wave. That is, the spectrum of the emission wave is received, and the dual frequency is measured and used for the temperature calculation. In addition, the emission wave can include a normal wave that is formed while reciprocating the inside of the object to be processed, and a longitudinal wave that is emitted to the outside of the object to be processed. The specific process of temperature calculation using the frequency will be described in detail later.

The object to be processed includes a solid object to be treated at a high temperature. That is, it may be a slab manufactured at a steel mill. For example, the material to be treated is a slab to be treated in a hot-rolling furnace of an ironworks. As soon as such slab is discharged from a heating furnace, the internal temperature of the slab can be calculated using the temperature measuring device of the embodiment.

The sound generator 10 may be a device for generating a sound wave and applying the generated sound wave to the object to be processed, or may be a device for generating a sound wave directly from the object by applying an impact to the object to be processed. For example, the sound generator 10 can generate a sound wave by applying a laser to the article to be processed with a laser, that is, by applying a laser shock. Or the sound generator 10 may include a hammer that can apply a physical impact to the article to be treated. That is, the hammer can charge the object to be processed and generate sound waves in the object to be processed.

The wave measuring device 20 is an apparatus for measuring the emission wave of the object S, for example, a spectrum analyzer can be used. That is, a spectrum analyzer can be used to receive the emission wave and measure the frequency from it. Further, the wave measuring device 20 may be disposed at a position where the reception ratio of the emission wave is high, and may be disposed on the same side as the sound generator on the basis of the object to be processed S, or on the opposite side. The wave measuring device 20 may be disposed in the vertical direction toward the object S to increase the reception ratio of the emission wave, and may be disposed slightly inclined. For example, 70 to 90 degrees relative to one surface of the object to be processed.

The thickness measuring device is a device for measuring the thickness of a material to be treated, and various known methods can be used. At this time, depending on the method of calculating the temperature of the object to be processed, the thickness of the object to be processed may not be measured.

The temperature calculating unit 30 includes a transceiver unit for receiving frequency data from the wave measuring device, a storage unit for storing predetermined data related to the speed and thickness of the sound wave of the object to be processed, And a calculation unit for calculating the calculation result. At this time, the transmitting / receiving unit may receive the thickness data from the thickness measuring device together with the frequency data. In other words, the temperature calculating unit 30 may or may not use the thickness data measured by the thickness measuring apparatus according to the temperature calculating method.

In the following, the principle and process of calculating the internal temperature of a hot object to be treated will be described. The internal temperature of the hot object can be calculated using the frequency, sound velocity and thickness of the object to be processed.

2 is a diagram conceptually showing progress of a sound wave in order to explain an embodiment of the present invention. That is, it represents a sound wave propagating inside the solid. There are transverse waves and denominators in the sound waves going through the solid interior. When such a sound wave meets the interface between solid and air, the transverse wave can not proceed into the air, but the longitudinal wave can propagate through the air. On the other hand, a sound wave traveling on the inside of a solid body having a boundary surface on both sides forms a standing wave instead of a traveling wave by repeating reflections at a boundary over time. The frequency of the standing wave is expressed by the following equation (the first equation).

Where n is the natural number of 1, 2, 3, ... indicating the order of the standing wave. V is the velocity of sound waves, and L is the distance between the interfaces, for example the thickness of the solid. B is the modulus of elasticity, and σ is the density. In this equation, the frequency of the standing wave is proportional to the speed of the sound wave and inversely proportional to the distance between the boundary surfaces.

On the other hand, the speed of sound waves and the distance between the interfaces can be expressed as a function of temperature. 3 is a graph illustrating changes in sound wave velocity according to an embodiment of the present invention. For example, FIG. 3 shows the speed of an ultrasonic wave traveling in a steel material having a different carbon content according to temperature. Here, X may represent a high carbon steel, and Y may represent a medium carbon steel. However, the material of the material to be treated is not limited at all, and can be applied to a material to be treated of various materials. Also, in steel, similar sound wave tendency changes according to temperature.

As shown in FIG. 3, it is shown that the speed of a sound wave traveling in each steel material changes with temperature. For example, if the temperature changes from 900 degrees to 500 degrees, about 400 degrees, the sound wave velocity increases by 8.8 percent. Steel containing slabs is present in 100% austenite phase at high temperature, phase transformation occurs in the middle, and exists in 100% ferrite phase at low temperature. Except for the temperature range at which the phase transformation takes place. That is, the line A represents the temperature-sound wave velocity linear relationship of the austenite phase in the two temperature-sound wave velocity measurement curves of the two steels, and the line B represents the ferrite phase in the temperature-sound wave velocity curve of the two steels. Temperature-sound wave velocity linear relationship.

When the temperature of the material to be treated is high, for example, the high temperature furnace outlet will follow the temperature-sound velocity linear relationship of the 100% austenite region before the transformation takes place. The inverse linear relationship between the sound velocity and the temperature can be expressed by a function of the following linear equation (the second equation).

Where a1 and b1 are the correlation coefficients of the function of temperature and sound velocity and may vary depending on the type of steel. Therefore, the correlation coefficient can be obtained when the sound wave velocity according to the temperature change is measured in various objects to be processed, as shown in FIG. For example, the speed of sound waves is measured in various objects to be processed and the speed correlation coefficients a1 and b1 are calculated using the inverse linear relationship of the sound wave speed V and the temperature T, Can be stored in advance in the storage unit of the temperature calculator described above.

On the other hand, the thickness L of the object to be processed S may vary with temperature. FIG. 4 is a graph showing a thickness variation according to an embodiment of the present invention. FIG. For example, FIG. 4 shows measured thickness / thickness expansion rates while increasing the temperature of a given steel.

As shown in Fig. 4, the thickness of the steel material changes with temperature. d For example, if the temperature is reduced by about 400 degrees, the thickness decreases by about 1%. As with the sound wave speed, a linear relationship is shown except for the transformation period. That is, the line A represents the temperature-thickness linear relationship of the austenite phase in the temperature-thickness measurement curve of the steel and the line B represents the temperature-thickness linear relationship of the ferrite phase in the temperature-thickness measurement curve of the steel . At this time, the thickness may be the thickness itself or the expansion ratio of the thickness. If the temperature of the article to be treated is high, for example, the high temperature furnace outlet will follow the thickness expansion ratio-temperature linear relationship of the austenite region.

The proportional linear relationship between thickness and temperature can be expressed as a function of the following first order equation (the third equation).

Where a2 and b2 are the correlation coefficients of the temperature and thickness functions, which can vary depending on the type of steel. Therefore, the correlation coefficient can be obtained when the thickness or the thickness expansion rate according to the temperature change is measured in various articles to be processed, as shown in FIG. For example, the thicknesses are measured in various articles to be processed, the velocity correlation coefficients a2 and b2 are calculated using the proportional linear relationship between the thickness L and the temperature T, Can be stored in advance in the storage unit of the temperature calculator.

As the temperature decreases, the sonic velocity increases and the thickness decreases, so that the old frequency of the longitudinal wave can rise somewhat. For example, referring to FIGS. 3 and 4, when the temperature changes by 400 degrees, the speed increases by 8.8% and the length decreases by 1%, resulting in a temperature of 1000 degrees and a thickness of 0.3 m For slabs, the temperature rises to 8.15 kHz at a fundamental frequency of about 8 kHz when the temperature drops to 900 degrees.

The internal temperature of the object to be processed can be calculated by applying the above-described measurement results of the sound wave velocity and the thickness and the frequency formula of the standing wave. First, a standing wave is generated in the article to be processed by using a sound generator. At this time, if a sound wave measuring means, that is, a wave measuring instrument is provided around the object to be processed, some of the energy of the standing wave corresponding to the longitudinal wave is measured through the air. The frequency of the sound wave measured in this manner can be derived by the following equation using the above-described first to third expressions. That is, a function formula of the temperature with respect to the frequency of the standing wave is derived.

Here, the correlation coefficients a1, b1, a2 and b2 can be obtained by the above-mentioned method and stored as the first and second setting data. Therefore, when the frequency of the standing wave emitted from the object to be processed S is measured, the temperature can be calculated by using the function formula. Fig. 5 shows the wave spectrum measured in the low carbon steel. The temperature can be calculated by selecting the frequency from these measurement results.

When n is 1, the frequency is referred to as a fundamental frequency, and an arbitrary frequency is represented by a multiple of the fundamental frequency. From the measurement of the frequency, it is possible to select the fundamental frequency (n = 1) or any other frequency to be used for calculating the temperature. For example, in a given environment, there are a variety of ways, such as using the frequencies at which the signal is most pronounced among the frequencies of the emission wave, or taking an average of several frequencies.

The obtained temperature value is derived from the frequency of a standing wave formed by reciprocating the inside of the object to be processed using the formula using the frequency, and thus can be understood as an average result of the internal temperature distribution of the object to be processed. That is, it can be estimated as the internal average temperature of the object to be processed.

On the other hand, in order to further increase the accuracy of the calculated temperature, a plurality of values may be utilized. For example, the temperature can be calculated using a plurality of frequencies. That is, a plurality of temperature values are calculated using different frequency values (n = 1, 2, 3, ...) and angular frequencies (F1, F2, F3 ...) The average value is calculated from the temperature value. That is, a plurality of temperature values can be arithmetically averaged and calculated as a final temperature value.

Alternatively, the temperature may be calculated using the average value of the frequencies. That is, the frequency at which n is 1 is selected as the fundamental frequency. In addition, the number of oscillations (n = 2, 3, etc.) when n exceeds 1 is selected and converted into a frequency at the time when n is 1, and is calculated as the auxiliary frequency. For example, when n is 2, the frequency F2 is selected, and the frequency value is divided by 2 to virtually convert the frequency to the frequency when n is 1. These frequency conversions can be performed at various values of n, and each reporting frequency can be obtained by dividing by n values of each frequency. Then, an average value of the fundamental frequency and the auxiliary frequency is calculated and obtained as average frequency data. Next, the temperature of the object to be processed is calculated using the average frequency data.

In the above description, the temperature is calculated using the temperature-thickness correlation coefficient of the object to be processed, but the temperature can also be calculated by directly measuring the thickness of the object to be processed at a high temperature. That is, using the first and second equations described above, the function formula of the temperature with respect to the frequency of the standing wave is derived as follows.

Here, the correlation coefficients a1 and b1 can be obtained by the above-described method and stored as the first setting data, and the thickness L of the object to be processed S can be measured and used. Therefore, when the frequency of the standing wave emitted from the object to be processed S is measured, the temperature can be calculated by using the function formula. In the case of using this formula, all of the n value, frequency selection, and various temperature calculation methods described above can be applied.

It should be noted that the above-described embodiments of the present invention are for the purpose of illustrating the present invention and not for the purpose of limitation of the present invention. In addition, it should be noted that the configurations and the methods disclosed in the above embodiments of the present invention may be combined with each other or applied cross-over to form a variety of different forms, and these variations may be regarded as the scope of the present invention. As a result, the present invention may be embodied in various other forms without departing from the scope of the appended claims and equivalents thereof, and various modifications may be made within the scope of the technical idea of the present invention. .

10: Sound generator
20: Wave Meter
30: Temperature calculator

Claims (20)

A sound generator capable of generating sound waves in the object to be processed;
A wave measuring device capable of measuring a discharge wave emitted from an object to be processed and measuring a frequency of an object to be processed from the discharge wave; And
Calculating a speed correlation coefficient (a1, b1) by using the inverse relationship between the sound wave speed and the temperature of the object to be processed; calculating a speed correlation coefficient (a1, b1) based on the thickness, the speed correlation coefficient, And a temperature calculator for calculating the temperature of the object to be processed by using the temperature sensor. The method according to claim 1,
Wherein the sound generator generates at least one of an audible sound wave and an ultrasonic wave in the object to be processed. The method of claim 2,
And the emission wave includes a standing wave formed while reciprocating inside the object to be processed. The method according to claim 1,
Wherein the emission wave includes a longitudinal wave emitted to the outside of the object to be processed,
Wherein the temperature of the object to be processed includes an internal temperature of the object to be processed. The method according to claim 1,
Wherein the sound generator generates sound waves and applies the sound waves to the object to be processed or applies an impact to the object to cause sound waves in the object to be processed. The method according to any one of claims 1 to 5,
And a thickness measuring device for measuring a thickness of the object to be processed. The method of claim 6,
The temperature calculator includes:
A transceiver receiving the frequency data from the wave measuring device or receiving the frequency data and the thickness data from the thickness measuring device;
A storage unit for storing predetermined data related to a sound wave speed and a thickness of the object to be processed; And
And a calculation unit for calculating a temperature of the object to be processed by using the frequency data and the setting data,
And the setting data includes the velocity correlation coefficient. Generating a sound wave on the object to be processed;
Measuring a discharge wave emitted from the object to be measured and measuring a frequency of the object to be processed from the discharge wave;
Calculating a velocity correlation coefficient (a1, b1) using the inverse relationship between the sound wave speed and temperature of the object to be processed and storing the same as first setting data; And
And calculating the temperature of the object to be processed by using the thickness of the object to be processed, the first setting data, the speed and frequency of the sound wave of the object to be processed. The method of claim 8,
Wherein the temperature of the object to be treated includes an internal temperature of the object to be processed. The method of claim 8,
And the emission wave includes a standing wave formed while reciprocating inside the object to be processed. delete delete delete The method of claim 8,
Before the process of calculating the temperature,
Calculating a thickness correlation coefficient (a2, b2) by using a proportional relationship between the thickness and the temperature of the object to be processed, and storing the correlation coefficient as a second setting data. The method of claim 8,
The step of calculating the temperature includes:
(T) is calculated by the following equation using the frequency (Fn) data of the measured object to be processed, the thickness (L) data of the measured object to be processed and the first setting data of the speed correlation coefficients (a1, b1) Wherein the temperature is measured by a temperature sensor.

n is a natural number of 1, 2, 3 ... 15. The method of claim 14,
The step of calculating the temperature includes:
(Tn) by using the following equation using the frequency setting data of the measured object to be processed (Fn), the first setting data of the speed correlation coefficients (a1, b1) and the second setting data of the thickness correlation coefficients ) ≪ / RTI >

n is a natural number of 1, 2, 3 ... The method according to claim 15 or 16,
Wherein a frequency at which n is 1 is selected as the frequency Fn data or a frequency at which the signal is most distinct among the frequencies of the emission wave is selected. The method according to claim 15 or 16,
The step of calculating the temperature includes:
Calculating a plurality of temperature values using angular frequency (Fn) data according to different n values and n values; And
And calculating an average value from the plurality of temperature values. The method according to claim 15 or 16,
The step of calculating the temperature includes:
selecting a frequency as a fundamental frequency when n is 1;
converting the frequency at which n exceeds 1 into a frequency at which n is 1 and calculating the frequency as an auxiliary frequency;
Calculating an average value of the basic frequency and the auxiliary frequency to obtain average frequency data; And
And calculating a temperature of the object to be processed using the average frequency data. The method of claim 10,
Wherein the object to be treated includes a slab discharged from the hot-rolling furnace.

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