Thickness measurement method and thickness measurement apparatus

Abstract

To reduce the measurement error of the thickness of a refractory material.SOLUTION: A thickness measurement method includes: an elastic wave output step of outputting elastic waves to a furnace wall; a reflection wave detection step of detecting reflection waves of the elastic waves reflected by the furnace wall; a frequency characteristic calculation step of executing frequency analysis on a signal based on the reflection waves and calculating frequency characteristics; and a thickness calculation step of, based on the calculated frequency characteristics and a correspondence between frequency characteristics and the thickness of a refractory material which have been previously associated, calculating the thickness of the refractory material. The correspondence between the frequency characteristics and the thickness of the refractory material is previously made by a correspondence step of associating the frequency characteristics with the thickness of the refractory material on the basis of the detected reflection waves detected upon forming the furnace wall.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a thickness measurement method and a thickness measurement device. [Background technology]

[0002] The furnace walls of industrial furnaces such as blast furnaces generally have a multi-layer structure consisting of, from the outside, a steel shell, monolithic refractories, and the main refractory material, firebricks. Because the innermost firebricks wear away from the core, measuring the thickness of the refractory is extremely important for furnace maintenance and management. The hearth of a blast furnace is particularly susceptible to severe wear because it is constantly exposed to molten iron, even when the furnace is not blowing. Furthermore, the hearth of a blast furnace is a part that cannot be directly repaired over the decades the furnace is in operation.

[0003] Accurate measurement of refractory thickness during operation allows for optimization of blast furnace operation. Optimizing blast furnace operation enables extending the life of the blast furnace and accurately predicting its lifespan and the timing of renovation. Therefore, improving the accuracy of refractory thickness measurement is extremely important.

[0004] As a method for measuring the thickness of a refractory material, for example, Patent Document 1 discloses a method for measuring the thickness of a refractory material by an impact acoustic wave resonance method. The method described in Patent Document 1 involves frequency analysis of a measured signal and converting the peak frequency into the thickness of the refractory material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-219751 Summary of the Invention [Problem to be solved by the invention]

[0006] In the impact acoustic wave resonance method, the peak frequency depends not only on the thickness of each layer of the furnace wall but also on the speed of sound. Therefore, the thickness of the refractory contained in the furnace wall depends on the speed of sound in each layer of the furnace wall and the peak frequency. Here, the speed of sound in the monolithic refractory contained in the furnace wall is not determined solely by its physical properties, but also varies depending on the construction. The monolithic refractory contained in the furnace wall is, for example, a stamped material. The density of the stamped material varies depending on the construction, and this variation in the density of the stamped material leads to variation in the speed of sound in the stamped material. The method described in Patent Document 1 does not take into account the difference in speed of sound due to the construction of the monolithic refractory. In other words, when converting the acquired peak frequency to the thickness of the refractory, the error due to the difference in speed of sound in the monolithic refractory is not taken into account.

[0007] An object of the present disclosure is to provide a thickness measurement method and a thickness measurement device that reduce errors in measuring the thickness of refractory materials. [Means for solving the problem]

[0008] [1] A method for measuring the thickness of a refractory material in a furnace having a furnace wall including a steel shell and a refractory material by an impact acoustic wave resonance method, an elastic wave output step of outputting an elastic wave to the furnace wall; a reflected wave detection step of detecting a reflected wave of the elastic wave reflected by the furnace wall; a frequency characteristic calculation step of calculating frequency characteristics by frequency analyzing a signal based on the reflected wave; a thickness calculation step of calculating a thickness of the refractory material based on the calculated frequency characteristics and a correspondence relationship between frequency characteristics and thicknesses of the refractory material that has been previously associated with each other; Including, the correspondence relationship between the frequency characteristics and the thickness of the refractory is established in advance by a correlation step of correlating the frequency characteristics with the thickness of the refractory based on reflected waves detected when the furnace wall is formed.

[0009] [2] The association step the correspondence relationship between the frequency characteristics calculated by the numerical analysis and the thickness of the refractory is corrected for the sound velocity of the refractory based on the reflected waves detected when the furnace wall is formed, and the correspondence relationship between the frequency characteristics and the thickness of the refractory is recalculated; The thickness measurement method according to [1] above.

[0010] [3] The association step The method for measuring the thickness of refractory material according to the above-mentioned [1] or [2], wherein the sound velocity of the refractory material is corrected so that the difference between a first resonance frequency, which is the frequency at which the amplitude spectrum of the reflected wave detected when the furnace wall is formed is maximized, and a second resonance frequency, which is the frequency at which the amplitude spectrum of the ultrasonic propagation motion simulation using a three-dimensional model having the thickness of the refractory material of the furnace wall when the furnace wall is formed is maximized, is equal to or less than a predetermined threshold value.

[0011] [4] The association step The method for measuring the thickness of a refractory material according to any one of [1] to [3] above, wherein the sound velocity of the refractory material is corrected for each position in the furnace where the reflected wave is detected when the furnace wall is formed.

[0012] [5] The thickness measurement method according to any one of the above [1] to [4], wherein the refractory material is a monolithic refractory material.

[0013] [6] The refractory material is a shaped refractory material, The associating step includes: The method for measuring the thickness of a refractory material according to any one of the above [1] to [5], wherein the correspondence relationship between the frequency characteristics calculated by numerical analysis and the thickness of the refractory material is recalculated by correcting the sound speed of the refractory material by the temperature of the refractory material based on reflected waves detected when the furnace wall is formed.

[0014] [7] A thickness measuring device for measuring the thickness of a refractory material in a furnace having a furnace wall including a steel shell and a refractory material by using an impact acoustic wave resonance method, an elastic wave output device that outputs elastic waves to the furnace wall; a reflected wave detection device that detects the reflected wave of the elastic wave reflected by the furnace wall; a control device; The control device performing frequency analysis on the signal based on the reflected wave to calculate frequency characteristics; calculating a thickness of the refractory material based on the calculated frequency characteristics and a correspondence relationship between frequency characteristics and thicknesses of the refractory material that has been previously associated with each other; a thickness measuring device that previously determines a correspondence relationship between the frequency characteristics and the thickness of the refractory material based on the reflected waves detected by the reflected wave detecting device when the furnace wall is formed. [Effects of the Invention]

[0015] According to the refractory thickness measurement method according to the present disclosure, it is possible to reduce measurement errors in the thickness of the refractory. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram schematically illustrating an example configuration of a thickness measurement device according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a diagram illustrating an example of frequency characteristics calculated according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a diagram showing an example of the correspondence relationship between the resonance frequency and the thickness of the refractory material. [Figure 4] FIG. 10 is a diagram illustrating an example of an error between a resonance frequency based on an actual measurement value and a resonance frequency based on a simulation according to an embodiment of the present disclosure. [Figure 5A] FIG. 10 is a diagram illustrating an example of a frequency characteristic calculated by a control unit of a control device according to an embodiment of the present disclosure. [Figure 5B] FIG. 10 is a diagram showing an example of a result of associating the thickness of a refractory material with frequency characteristics. [Figure 6] 10 is a flowchart illustrating an example of a process performed by a thickness measurement device according to an embodiment of the present disclosure to associate a thickness of a refractory material with a resonance frequency. [Figure 7] 10 is a flowchart illustrating an example of a process for measuring the thickness of a refractory material by a thickness measurement device according to an embodiment of the present disclosure. [Figure 8] FIG. 1 is a schematic diagram illustrating an example of a usage mode of a thickness measurement device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0018] FIG. 1 is a diagram illustrating an example of a thickness measurement device 1 according to an embodiment of the present disclosure.

[0019] The thickness measuring device 1 includes an elastic wave output device 10, a reflected wave detection device 20, and a control device 30. The thickness measuring device 1 is a device that can measure the thickness of refractory material in a furnace having a furnace wall including a steel shell and refractory material by the impact elastic wave resonance method.

[0020] The elastic wave output device 10 outputs elastic waves to the furnace wall of an industrial furnace such as a blast furnace. The elastic wave output device 10 may be, for example, an impact hammer or a vibration exciter. When the elastic wave output device 10 is an impact hammer, for example, an impact hammer having frequency characteristics that allow the maximum value of the expected resonance frequency to be measured is used. The maximum value of the expected resonance frequency can be calculated in advance by simulation.

[0021] The reflected wave detection device 20 receives the elastic waves output from the elastic wave output device 10 and detects the reflected waves reflected from the furnace wall. The reflected wave detection device 20 may be, for example, an accelerometer. When the reflected wave detection device 20 is an accelerometer, it is preferable to use an accelerometer that can detect acceleration in the normal direction of the steel shell of the furnace wall.

[0022] The control device 30 performs frequency analysis on a signal based on the reflected wave detected by the reflected wave detection device 20, calculates frequency characteristics, and measures the thickness of the refractory material based on the calculated frequency characteristics. The control device 30 is, for example, a general-purpose computer such as a PC (Personal Computer), but may also be realized by a dedicated electronic device. The control device 30 may load a dedicated program to execute the processes of the present disclosure.

[0023] As shown in FIG. 1, the control device 30 includes a control unit 31, a storage unit 32, and an output unit 33.

[0024] The control unit 31 executes various processes related to the operation of the control device 30 and controls each unit of the control device 30. The control unit 31 includes at least one processor, at least one dedicated circuit, or a combination of these. The processor is a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for a specific process. The control unit 31 may realize its control functions by executing a program stored in the storage unit 32.

[0025] The storage unit 32 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The storage unit 32 functions as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 32 stores, for example, programs and data used in the operation of the thickness measurement device 1, and data obtained by the operation of the thickness measurement device 1.

[0026] The output unit 33 includes at least one output device. The output device is, for example, a display. The display is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescent) display. The output unit 33 outputs the calculation results of the control unit 31 and the information stored in the memory unit 32.

[0027] Next, the processing executed by the control unit 31 of the control device 30 will be described.

[0028] (Calculation method of frequency characteristics) The control unit 31 performs frequency analysis on a signal based on the reflected wave detected by the reflected wave detection device 20 to calculate frequency characteristics. The control unit 31 calculates, for example, an amplitude spectrum as the frequency characteristics to be calculated, but is not limited to this. The control unit 31 may also calculate a frequency response function based on the elastic wave output by the elastic wave output device 10 and the reflected wave detected by the reflected wave detection device 20. Examples of frequency analysis methods include a discrete Fourier transform (DFT) and a fast Fourier transform (FFT), which performs a DFT at high speed, but are not limited to these. Analysis using a wavelet transform may also be performed. The control unit 31 may perform frequency analysis on the reflected wave detected by the reflected wave detection device 20 as is to calculate the amplitude spectrum. Alternatively, the control unit 31 may use a band-pass filter to perform frequency analysis on only signals in a specific frequency band to calculate the amplitude spectrum. Furthermore, the control unit 31 may perform frequency analysis on a signal extracted from the detected reflected wave using a window function to calculate the amplitude spectrum.

[0029] Hereinafter, a method using a discrete Fourier transform will be described as a method for the control unit 31 to calculate frequency characteristics. At time t, the sampling number of the acceleration signal detected by the reflected wave detection device 20 is set to n, and the signal obtained by sampling the acceleration signal is set to a(n). In this case, the discrete Fourier transform A(k) of a(n) can be calculated by the following equation (1).

number

number

number

[0030] (Method of Corresponding Frequency Characteristics and Refractory Thickness) The control unit 31 of the control device 30 associates frequency characteristics with refractory thickness in advance based on the reflected waves detected by the reflected wave detection device 20 when the furnace wall is formed. By associating frequency characteristics with refractory thickness in this way based on the reflected waves actually detected when the furnace wall is formed, the control unit 31 can associate frequency characteristics with refractory thickness taking into account the speed of sound of the refractory contained in the formed furnace wall. For example, the control unit 31 can associate the frequency characteristics with refractory thickness calculated by numerical analysis such as the finite element method by correcting the speed of sound of the refractory based on the reflected waves detected by the reflected wave detection device 20 when the furnace wall is formed. The speed of sound of the refractory refers to the speed of sound traveling through the refractory.

[0031] Below, we will explain how to associate frequency characteristics with refractory thickness using the results of vibration simulation using the finite element method. The finite element method is a numerical analysis method for approximately solving differential equations, and performs calculations by dividing a continuum into elements of finite size. The propagation of ultrasonic waves in a continuum is expressed by the differential equation shown in equation (4).

number

[0032] When equation (4) is divided into elements of finite size, the ultrasonic wave propagation motion at time tn is expressed by equation (5).

number

number

[0033] The control unit 31 generates a 3D model of the furnace divided into elements of finite size. The 3D model of the furnace may be the entire furnace. Alternatively, the 3D model of the furnace may be only the refractory material whose thickness is to be measured and the outer layer region of the refractory material. The control unit 31 generates multiple 3D models, each with a different refractory thickness.

[0034] The control unit 31 sequentially calculates the ultrasonic wave propagation motion of Equation (5) using each of the generated three-dimensional models. As a result of simulating the ultrasonic wave propagation motion (ultrasonic wave propagation simulation) using the three-dimensional model of the refractory thickness T, the acceleration signal observed at the acceleration measurement position {xp} is calculated as a Txp (n). In this case, a Txp Discrete Fourier transform of (n) A Txp (k) can be calculated using equation (6).

number

[0035] Figure 2 shows the frequency characteristic A calculated using equation (6). T In the example shown in FIG. 2, the frequency characteristic A T (k) is the frequency f T The control unit 31 controls the T From (k), f at the thickness T of the refractory T is calculated using equation (7) and used as the resonant frequency.

number

[0036] The control unit 31 calculates equation (7) for each refractory thickness T to derive a function that converts between the refractory thickness T and the resonance frequency f. FIG. 3 is an example of a graph in which the resonance frequency is calculated for each refractory thickness T. The circles in FIG. 3 indicate the resonance frequencies obtained by performing an ultrasonic propagation simulation for each refractory thickness. The control unit 31 may perform a simulation using a representative refractory thickness and derive an approximate equation that converts between the refractory thickness and the resonance frequency, as shown by the dotted line in FIG. 3. The control unit 31 may perform a simulation using a refractory thickness for each desired thickness resolution and derive a function that provides a one-to-one correspondence between the refractory thickness and the resonance frequency.

[0037] (Method for correcting the sound velocity of monolithic refractories) When numerically analyzing the propagation of elastic waves using the finite element method, the sound velocity along the propagation path is taken into account in equations (4) and (5). The stamped material used as monolithic refractory in the furnace wall structure is compacted using a rammer. The shape of the stamped material changes depending on how it is compacted, which affects the propagation velocity of elastic waves. The stamped material is sandwiched between the refractory bricks and the cooling staves (CS) or steel shell, so the propagation velocity cannot be measured.

[0038] Therefore, the control unit 31 corrects the sound velocity of the monolithic refractory. Hereinafter, the method for correcting the sound velocity of the monolithic refractory will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of the resonance frequency fMTmax calculated by measuring a refractory having a thickness Tmax using the thickness measuring device 1 when the furnace wall is formed, and the resonance frequency fCTmax of the thickness Tmax calculated by the control unit 31 using the finite element method.

[0039] Here, the thickness Tmax is the thickness of the refractory of the furnace wall when the furnace wall is formed. The resonance frequency fMTmax is the frequency (first resonance frequency) at which the amplitude spectrum |A(k)| is maximum. The amplitude spectrum |A(k)| is calculated by outputting an elastic wave from the elastic wave output device 10 toward the furnace wall having a refractory thickness Tmax, detecting a reflected wave based on the elastic wave by the reflected wave detection device 20, and then calculating the amplitude spectrum |A(k)| by the control unit 31 based on the reflected wave. The resonance frequency fCTmax is calculated by outputting an elastic wave from the elastic wave output device 10 toward the furnace wall having a refractory thickness Tmax. Txp (k)| is the frequency (second resonance frequency) at which the amplitude spectrum |A Txp (k)| is the amplitude spectrum of the vibration propagating through the refractory material of thickness Tmax calculated by the control unit 31 using a three-dimensional model of a furnace having refractory material of thickness Tmax to simulate the ultrasonic propagation motion using the finite element method (ultrasonic propagation simulation).

[0040] If there is a difference between the sound velocity of the actual stamp material and the sound velocity of the stamp material used in the ultrasonic propagation simulation, an error will occur between the first resonance frequency fMTmax and the second resonance frequency fCTmax, as shown in Fig. 4. If the difference between the first resonance frequency fMTmax and the second resonance frequency fCTmax is equal to or greater than a threshold, the control unit 31 changes the sound velocity of the stamp material taken into account in equations (4) and (5), performs the calculations of equations (5) to (7) again, and recalculates the second resonance frequency fCTmax. If the difference between the second resonance frequency fCTmax and the first resonance frequency fMTmax is less than the threshold, the sound velocity of the stamp material used in the ultrasonic propagation simulation when the second resonance frequency fCTmax is recalculated is determined to be the sound velocity of the actual stamp material.

[0041] The sound velocity of the monolithic refractory may be corrected for each thickness measurement position of the furnace wall using the thickness measurement device 1. Because the stamped material is tamped using a rammer, the sound velocity of the stamped material may vary depending on the position, even within the same furnace. Therefore, since the first resonance frequency fMTmax may differ depending on the thickness measurement position, the sound velocity of the monolithic refractory may be corrected for each thickness measurement position.

[0042] For more accurate calculation, the control unit 31 may correct the sound velocity based on the temperature of the shaped refractory. For example, the temperature inside the shaped refractory may be interpolated by taking the temperature of the furnace inner end of the shaped refractory as the molten iron temperature and the temperature of the furnace outer end of the shaped refractory as the value measured by a side plate thermometer in contact with the surface of the shaped refractory, assuming that the temperature decreases linearly from the furnace inner side to the furnace outer side.

[0043] (Calculation method for refractory thickness) The control unit 31 calculates the thickness of the refractory material based on the frequency characteristics calculated by frequency analysis of the signal based on the reflected wave detected by the reflected wave detection device 20 and the correspondence relationship between the frequency characteristics and the thickness of the refractory material that was previously associated when the furnace wall was formed. The correspondence relationship between the frequency characteristics and the thickness of the refractory material that was previously associated when the furnace wall was formed may be expressed, for example, as an approximate equation for converting the thickness of the refractory material to the resonance frequency. Hereinafter, a method for calculating the thickness of the refractory material using the approximate equation for converting the thickness of the refractory material to the resonance frequency will be described with reference to FIGS. 5A and 5B.

[0044] Fig. 5A is a diagram showing an example of frequency characteristics calculated by the control unit 31 by performing frequency analysis on a signal based on a reflected wave detected by the reflected wave detection device 20. Fig. 5B is a diagram showing an example of an approximate formula for converting the thickness of the refractory material to the resonant frequency, and the approximate formula is indicated by a dashed line. In the example shown in Fig. 5A, the frequency f0 at which the amplitude of the frequency characteristics is maximum is obtained as the resonant frequency using equation (8).

number

[0045] In the above description, an example has been disclosed in which the control device 30 executes the process of previously associating the frequency characteristics with the thickness of the refractory material based on the reflected waves detected by the reflected wave detection device 20 when the furnace wall is formed, but this is not limiting. For example, the process of previously associating the frequency characteristics with the thickness of the refractory material based on the reflected waves detected by the reflected wave detection device 20 when the furnace wall is formed may be executed by a device other than the control device 30.

[0046] An example of control processing of the thickness measuring device 1 according to this embodiment having the above configuration will be described below with reference to Figs. 6 to 8. Fig. 6 is a flowchart showing an example of the flow of a first process, which is a process for previously associating frequency characteristics with the thickness of the refractory material based on the reflected waves detected by the reflected wave detecting device 20 when the furnace wall 2 is formed. Fig. 7 is a flowchart showing an example of the flow of a second process, which is a process for calculating the thickness of the refractory material. Fig. 8 is a schematic diagram showing an example of a usage mode of the thickness measuring device 1 according to this embodiment.

[0047] In this embodiment, the thickness measuring device 1 performs a first process when the furnace wall 2 shown in Fig. 8 is formed. Thereafter, a second process is performed when measuring the thickness of the refractory material included in the furnace wall 2. The first process will be described below with reference to Fig. 6.

[0048] When the furnace wall 2 is formed, the control unit 31 instructs the elastic wave output device 10 to output elastic waves. Upon receiving the instruction from the control unit 31, the elastic wave output device 10 outputs elastic waves to the furnace wall 2 (step S101).

[0049] The reflected wave detecting device 20 receives the elastic wave output in step S101 and detects the reflected wave reflected from the furnace wall 2. The reflected wave detecting device 20 transmits signal information based on the detected reflected wave to the control unit 31 (step S102).

[0050] The control unit 31 calculates the first resonant frequency from the signal information based on the reflected wave received in step S102 (step S103).

[0051] The control unit 31 performs an ultrasonic wave propagation simulation based on the thickness of the refractory material used in the furnace wall 2 and sound speed information in each layer of the furnace wall 2, and calculates the second resonance frequency (step S104).

[0052] The control unit 31 compares the first resonance frequency calculated in step S103 with the second resonance frequency calculated in step S104, and determines whether the difference is less than a threshold value (step S105). If the difference is not less than the threshold value (step S105: No), the control unit 31 corrects the sound speed in each layer of the furnace wall 2 (step S106), and returns to step S104.

[0053] If the difference between the first resonance frequency and the second resonance frequency is less than the threshold value (step S105: Yes), the control unit 31 determines the sound speed in each layer of the furnace wall 2 to be the currently set value and stores it in the memory unit 32 (step S107).

[0054] Thereafter, the control unit 31 performs an ultrasonic wave propagation simulation for a plurality of refractory thicknesses using the sound speed determined in step S107, associates the refractory thickness with the resonance frequency, and stores the generated association information in the storage unit 32 (step S108). In this way, the control unit 31 corrects the sound speed of the refractory based on the reflected wave detected when the furnace wall 2 is formed, and recalculates the correspondence between the refractory thickness and the resonance frequency.

[0055] Next, the second process will be described with reference to Fig. 7. When measuring the thickness of the refractory material, the control unit 31 instructs the elastic wave output device 10 to output an elastic wave. Upon receiving the instruction from the control unit 31, the elastic wave output device 10 outputs an elastic wave to the furnace wall 2 (step S201).

[0056] The reflected wave detecting device 20 receives the elastic wave output in step S201 and detects the reflected wave reflected from the furnace wall 2. The reflected wave detecting device 20 transmits signal information based on the detected reflected wave to the control unit 31 (step S202).

[0057] The control unit 31 calculates the third resonant frequency from the signal information based on the reflected wave received in step S202 (step S203).

[0058] The control unit 31 calculates the thickness of the refractory material based on the third resonance frequency calculated in step S203 and the association information generated in step S108 (step S204).

[0059] As described above, the refractory thickness measurement method according to this embodiment includes the following steps: an elastic wave output step of outputting an elastic wave to the furnace wall 2; a reflected wave detection step of detecting a reflected wave of the elastic wave reflected by the furnace wall 2; a frequency characteristic calculation step of calculating frequency characteristics by performing frequency analysis on a signal based on the detected reflected wave; and a thickness calculation step of calculating the thickness of the refractory based on the calculated frequency characteristics and a correspondence relationship between the frequency characteristics and the refractory thickness that has been previously associated with each other. The correspondence relationship between the frequency characteristics and the refractory thickness is previously associated with each other in the correspondence step of associating the frequency characteristics with the refractory thickness by numerical analysis based on the speed of sound detected when the furnace wall 2 is formed. In this way, the refractory thickness measurement method according to this embodiment previously associates the frequency characteristics with the refractory thickness based on the reflected wave actually detected when the furnace wall 2 is formed. Therefore, the refractory thickness measurement method according to this embodiment can measure the thickness of the refractory taking into account the actual speed of sound in the refractory, thereby reducing measurement errors in the refractory thickness.

[0060] The present disclosure is not limited to the above-described embodiments. For example, multiple blocks shown in the block diagrams may be integrated, or one block may be divided. Instead of executing multiple steps shown in the flowcharts in chronological order as described, the steps may be executed in parallel or in a different order depending on the processing capabilities of the device executing each step, or as needed. Other modifications are possible within the scope of the present disclosure.

[0061] For example, in the above-described embodiment, the elastic wave output device 10, the reflected wave detection device 20, and the control device 30 are configured as separate devices, but the elastic wave output device 10, the reflected wave detection device 20, and the control device 30 may be configured as a single device.

[0062] For example, in the above embodiment, the control unit 31 performs frequency analysis of the signal based on the reflected wave detected by the reflected wave detection device 20 , but the frequency analysis may be performed by the reflected wave detection device 20 . [Explanation of symbols]

[0063] 1 Thickness measurement device 10 Elastic wave output device 20 Reflected wave detection device 30 Control device 31 Control Unit 32 Storage section 33 Output section 2 Furnace wall

Claims

1. A method for measuring the thickness of a refractory material in a furnace having a furnace wall including a steel shell and a refractory material by an impact acoustic wave resonance method, comprising: an elastic wave output step of outputting an elastic wave to the furnace wall; a reflected wave detection step of detecting a reflected wave of the elastic wave reflected by the furnace wall; a frequency characteristic calculation step of calculating frequency characteristics by frequency analyzing a signal based on the reflected wave; a thickness calculation step of calculating a thickness of the refractory material based on the calculated frequency characteristics and a correspondence relationship between frequency characteristics and thicknesses of the refractory material that has been previously associated with each other; Including, the correspondence relationship between the frequency characteristics and the thickness of the refractory is established in advance by a correlation step of correlating the frequency characteristics with the thickness of the refractory based on reflected waves detected when the furnace wall is formed.

2. The associating step includes:

2. The method for measuring the thickness of a refractory material according to claim 1, wherein the correspondence relationship between the frequency characteristics calculated by numerical analysis and the thickness of the refractory material is recalculated by correcting the sound speed of the refractory material based on reflected waves detected when the furnace wall is formed.

3. The associating step includes:

3. The method for measuring the thickness of a refractory material according to claim 2, wherein the sound velocity of the refractory material is corrected so that a difference between a first resonance frequency, which is a frequency at which an amplitude spectrum of a reflected wave detected when the furnace wall is formed is maximized, and a second resonance frequency, which is a frequency at which an amplitude spectrum of an ultrasonic wave propagation motion simulation using a three-dimensional model having a thickness of the refractory material of the furnace wall when the furnace wall is formed is maximized, is equal to or less than a predetermined threshold value.

4. The associating step includes:

4. The method for measuring the thickness of a refractory material according to claim 3, wherein the sound velocity of the refractory material is corrected for each position in the furnace where the reflected wave is detected when the furnace wall is formed.

5. The method for measuring the thickness of a refractory material according to any one of claims 1 to 4, wherein the refractory material is a monolithic refractory material.

6. The refractory material is a shaped refractory material, The associating step includes:

2. The method for measuring the thickness of a refractory according to claim 1, further comprising the steps of: correcting the sound speed of the refractory by a temperature of the refractory based on a reflected wave detected when the furnace wall is formed; and recalculating the correspondence relationship between the frequency characteristics calculated by the numerical analysis and the thickness of the refractory.

7. A thickness measurement device for measuring the thickness of a refractory material of a furnace having a furnace wall including a steel shell and a refractory material by using an impact acoustic wave resonance method, an elastic wave output device that outputs elastic waves to the furnace wall; a reflected wave detection device that detects the reflected wave of the elastic wave reflected by the furnace wall; a control device; The control device performing frequency analysis on the signal based on the reflected wave to calculate frequency characteristics; calculating a thickness of the refractory material based on the calculated frequency characteristics and a correspondence relationship between frequency characteristics and thicknesses of the refractory material that has been previously associated with each other; a thickness measuring device that previously determines a correspondence relationship between the frequency characteristics and the thickness of the refractory material based on the reflected waves detected by the reflected wave detecting device when the furnace wall is formed.

Images