JP2012163524A - Brick thickness measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brick thickness measuring method with which the thickness of a high-temperature brick in a coke oven or a finery can be easily and accurately measured.SOLUTION: A brick thickness measuring method is characterized in filling a gap between an antenna 12 and a brick 13 with a heat insulation layer 16 having a thickness of 4 to 300 mm in the method including radiating an electromagnetic wave from the antenna 12 to the brick 13, receiving the reflection of the electromagnetic wave on a boundary surface of materials 14 having different refraction factors by means of the antenna 12, and measuring a brick thickness through hot working from a time (t) from reflecting the electromagnetic wave on the back of the brick 13 to returning to the receiving antenna 12 and an electromagnetic wave propagation velocity (v).

Description

  The present invention relates to a method for measuring the thickness of a high-temperature brick in a coke oven or a refining furnace.

  In various furnaces used in the steel making process, there are many needs to measure the thickness of the bricks used hot. For example, there is an application in the diagnosis of a coke oven wall, which will be described below.

  FIG. 1 shows a schematic perspective view of a coke oven (here, a chamber-type coke oven). In the coke oven, the coal in the charcoal vehicle 7 is usually charged into the carbonization chamber 1 from 4 to 5 carbonization holes 8 per carbonization chamber, the fuel gas is combusted in the combustion chamber 2, and the heat is generated in the carbonization chamber 1. It is a furnace that carbonizes the coal inside to produce coke. Therefore, the coke oven main body is composed of bricks serving as heat transfer materials that transmit the heat of the combustion chamber 2 to the carbonization chamber 1 side. The coke generated in the carbonization chamber 1 is extruded by the ram 3a of the extruder 3. The side where the extruder 3 is located is called the machine side, and the side where the coke comes out is called the coke side. Since coke generation takes a long time, a coke oven generally performs a continuous operation in which a large number of carbonization chambers 1 and combustion chambers 2 are alternately arranged and coke is sequentially generated in each carbonization chamber 1.

  FIG. 2 is a plan sectional view of the coke oven. During the carbonization, the coal expands, and the expansion pressure acts on the furnace wall 4 (the side wall of the carbonization chamber, which corresponds to the outer wall of the combustion chamber). Further, during the coke extrusion, extrusion shear force and pressure act on the furnace wall 4. Due to the effects of such forces from years of operation, the bricks and joints are cracked and chipped. In addition, the binder 5 connecting the furnace walls may be cut, or the furnace wall 4 may be deformed or collapsed. When the furnace wall 4 protrudes into the inside of the carbonization chamber 1 and is deformed, a load is applied to the furnace wall 4 when the coke is pushed out by the ram 3a, the wear of the furnace wall 4 progresses, and finally the coke extrusion itself becomes impossible. Operation trouble occurs.

  In such a case, measures are taken to eliminate the overhang by cutting the furnace wall 4 so that extrusion is possible. On the other hand, the furnace brick structure is weakened by cutting and thinning the furnace wall 4. If the furnace wall thickness falls below a certain limit, it will not be able to withstand the expansion pressure and extrusion load, so repair such as transshipment of the furnace wall 4 is necessary, but it is difficult to manage the furnace wall thickness and measurement is difficult. If the transshipment repair is not performed at the time, a large furnace body damage such as collapse of the furnace wall 4 may occur. Therefore, a technique for accurately grasping the furnace wall thickness is desired.

  Moreover, many of the furnaces used in the iron making process have refractory bricks attached to the inside of the iron skin container, such as a refining furnace. Since the molten iron or molten steel is placed in the iron-shell container, wear such as cracks due to heat or chemical reaction or reduction in brick thickness gradually occurs. Temporary repairs such as thermal spray repairs are also possible, but in the end, bricks are replaced and repaired. Refurbishment of refractory bricks is expensive, so it is desirable to make furnace repair judgment at an appropriate time. Moreover, if the wear state of the brick is not correctly grasped, it may cause a serious trouble such as leakage steel. Therefore, a technique for measuring the thickness of the brick is necessary as one of the furnace body diagnosis.

JP 2007-127672 A JP-A-9-264735 JP 2006-153845 A

  Many of the conventional in-furnace diagnostic methods measure the furnace width.

  For example, Patent Document 1 describes a method for measuring the furnace width because the furnace width is necessary information when repairing the thermal spraying to repair the roughness of the furnace wall. At this time, when the thickness of the furnace wall is reduced from the carbonization chamber side, the furnace width increases and the remaining furnace wall thickness can be estimated.

  However, if the work is performed such that the furnace wall 4 protrudes toward the carbonization chamber 1 by cutting the binder 5, and the furnace wall 4 is cut, the furnace wall thickness may be reduced even if the furnace width is normal. Therefore, the furnace width information alone is not sufficient for grasping the furnace wall thickness for judging the strength of the brick structure.

  On the other hand, there are Patent Literature 2 and Patent Literature 3 as methods for measuring the furnace wall thickness.

  However, Patent Document 2 is a method in which the iron skin is opened and the detector is brought into contact with the brick, and measurement can be performed only at a portion where the detector can be brought into contact with the brick. In fact, it is difficult to implement when the target brick is hot.

  Moreover, although patent document 3 is a non-contact-type brick thickness meter using a microwave, since it is the structure which sandwiches (1) space, (2) microwave passage window, and (3) space between an antenna and a brick, it is a brick. It is difficult to distinguish the reflected waves from the front surface and the back surface, and it is necessary to devise noise error removal.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brick thickness measuring method that can easily and accurately measure the thickness of a high-temperature brick in a coke oven or a refining furnace. It is what.

  In order to solve the above problems, the present invention has the following features.

  [1] The electromagnetic wave is radiated from the transmitting antenna to the brick, and the reflection of the electromagnetic wave at the boundary surface of materials having different refractive indexes is received by the receiving antenna, and the electromagnetic wave is reflected by the back surface of the brick and returns to the receiving antenna. Thickness measurement characterized by filling a heat-insulating layer having a thickness of 4 to 300 mm between a transmitting antenna and a receiving antenna and a brick in a method for measuring the thickness of a brick between heat and the electromagnetic wave propagation speed of the brick. Method.

  [2] The brick thickness measurement method according to [1], wherein the thickness of the brick is corrected according to the thickness of the heat insulating layer filled between the transmission antenna and the reception antenna and the brick.

  [3] The brick thickness measurement according to [1] or [2], wherein a material that does not transmit electromagnetic waves is opened when the brick whose thickness is to be measured is located inside a material that does not transmit electromagnetic waves. Method.

  In the present invention, the thickness of a high-temperature brick in a coke oven or a refining furnace can be easily and accurately measured by using electromagnetic waves.

It is a perspective view of a coke oven. It is a coke oven top view. It is a conceptual diagram which measures the brick thickness in the electromagnetic waves by Embodiment 1 of this invention. It is a conceptual diagram of the waveform of the transmission wave and reception wave at the time of the brick thickness measurement by Embodiment 1 of this invention. It is a conceptual diagram which measures the brick thickness in the electromagnetic waves by Embodiment 2 of this invention. It is a figure which shows the measurement result of the brick thickness in Example 1 of this invention.

  Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 3 is a conceptual diagram for measuring the brick thickness of the electromagnetic wave according to Embodiment 1 of the present invention. In this Embodiment 1, the case where the thickness measurement of the furnace wall brick of a chamber furnace type coke oven is performed is considered.

  As shown in FIG. 3, when an electromagnetic wave (transmitted wave) is radiated to the brick 13 from an antenna (transmitting antenna) 12 attached to the brick thickness measuring device (sensor box) 11, a material 14 having a material having a refractive index different from that of the brick 13. A reflected wave is obtained at the boundary between and the received wave is received by the antenna (receiving antenna) 12. The material 14 having a refractive index different from that of the brick 13 is air or an iron member.

  FIG. 4 is a conceptual diagram of waveforms of a transmission wave and a reception wave when the brick thickness is measured in the first embodiment.

  As shown in FIG. 4, the time difference between the transmission wave and the reception wave is the time required for reflection of the electromagnetic wave (reflection time). That is, the time from when the electromagnetic wave is radiated to the brick 13 from the transmitting antenna 12 and the reflection of the electromagnetic wave at the boundary surface (back surface of the brick 13) of the material 14 having a different refractive index is received by the receiving antenna 12 is the reflection time. . When the reflection time t and the propagation speed of electromagnetic waves are v, the thickness of the brick is calculated by D = tv / 2.

  At that time, since the propagation velocity v of the electromagnetic wave varies depending on the refractive index of the medium, it is necessary to calibrate with the refractive index of the target brick 13 in the initial stage. Further, since the propagation speed v of electromagnetic waves varies depending on the temperature environment, it is desirable to calculate the thickness in consideration of the temperature dependence of the propagation speed v when measuring the high temperature brick 13. In addition, it is appropriate that the electromagnetic wave is a pulse wave in the range of 100 to 3000 MHz from the measurement accuracy.

  In addition, in the first embodiment, as shown in FIG. 3, a heat insulating layer (heat insulating material: ceramic cloth, for example) 16 is provided between the antenna 12 and the brick 13 without bringing the antenna 12 into contact with the brick 13. I try to fill it. Thereby, compared with the case where a space | gap is simply provided between the antenna 12 and the brick 13, the thermal load to the antenna 12 by the high temperature brick 13 can be reduced significantly.

  In addition, since the heat insulating layer 16 is filled between the antenna 12 and the brick 13, when calculating the thickness of the brick 13, the thickness of the heat insulating material 16 between the antenna 12 and the brick 13 (that is, the antenna 12 and It is necessary to correct the measurement results according to the distance between the bricks 13) and the type (material) of the heat insulating material 16. Here, it is desirable to determine in advance the degree of influence according to the thickness and type of the heat insulating material 16 prior to measurement.

  For example, when a certain type of ceramic cloth having a thickness δ is filled as the heat insulating material 16 between the antenna 12 and the brick 13 under a certain temperature condition, from the measurement value calculated by D = tv / 2, Correction for subtracting, for example, 0.25 times the thickness (distance between the antenna 12 and the brick 13) δ may be performed.

  Incidentally, when a gap is simply provided between the antenna 12 and the brick 13 under a certain temperature condition, for example, 0.15 times the distance δ between the antenna 12 and the brick 13 from the measured value calculated by D = tv / 2. However, depending on the measurement location, it is difficult to accurately detect the distance δ between the antenna 12 and the brick 13, and the measurement value calculated by D = tv / 2 is accurate. It is difficult to correct well. The numbers 0.25 times δ when the ceramic cloth is filled and 0.15 times δ when the gap is provided are not fixed, and differ depending on the filling material, temperature conditions, etc. It is a value set based on experimental results and experience.

  On the other hand, the measurement value calculated by D = tv / 2 can be accurately corrected by previously filling the space between the antenna 12 and the brick 13 with the heat insulating layer 16 capable of measuring the thickness δ.

  The distance δ between the antenna 12 and the brick 13 (thickness of the heat insulating layer 16) δ is suitably 4 to 300 mm from the heat insulating effect and the sensitivity of receiving the reflected wave.

  In addition, the heat insulating layer (heat insulating material) 16 filled between the antenna 12 and the brick 13 is not a material whose thickness varies depending on how it is pressed, such as a blanket, and the thickness of a heat insulating board does not easily change. A material is preferred. However, a non-uniform material that is reinforced with a wire or the like is not desirable.

  If a brick thickness measuring device (sensor box) 11 including an antenna (transmitting antenna, receiving antenna) 12 is attached and scanned, a wide range of brick thicknesses can be measured in a short time. The wheel may have another form, for example, a caterpillar. The brick thickness measuring device 11 may be powered and run on its own, or may be mounted on another mobile device and scanned.

  Here, the brick thickness measuring apparatus 11 according to the first embodiment includes an electromagnetic wave transmitting / receiving antenna 12 and a propagation time measuring means required for electromagnetic wave transmission / reception. Further, it is desirable to include means for calculating the propagation distance from the propagation time and a storage device for measurement data.

[Embodiment 2]
FIG. 5 is a conceptual diagram for measuring the brick thickness in the electromagnetic wave according to Embodiment 2 of the present invention. In this Embodiment 2, the case where the brick thickness measurement of the furnace with which the brick is stuck inside the iron skin container like a refining furnace is performed in mind.

  The basic configuration of the second embodiment is the same as that of the first embodiment described above. However, as shown in FIG. 5, an electromagnetic wave is transmitted from an antenna (transmitting antenna) 12 attached to a brick thickness measuring device (sensor box) 11. When (transmitted wave) is radiated to the brick 13, since the electromagnetic wave does not pass through the iron skin 15, the opening 17 is provided in the iron skin 15 portion where the electromagnetic wave is desired to pass. When an electromagnetic wave is radiated from the antenna (transmission antenna) 12 to the brick 13 via the opening 17, a reflected wave is obtained at the boundary with the material 14 made of a material having a refractive index different from that of the brick 13, and the reflected wave is The signal is received by the antenna (reception antenna) 12. The material 14 having a refractive index different from that of the brick 13 is air or an iron member.

  In addition, the conceptual diagram of the waveform of the transmission wave at the time of brick thickness measurement in this Embodiment 2 and a reception wave is the same as that of above-mentioned FIG. 4, Since embodiment is also the same, description is abbreviate | omitted.

  Here, the brick thickness measuring apparatus 11 according to the second embodiment includes an electromagnetic wave transmitting / receiving antenna 12 and a propagation time measuring means required for electromagnetic wave transmission / reception. Further, it is desirable to include means for calculating the propagation distance from the propagation time and a storage device for measurement data.

  As Example 1 of the present invention, the thickness of a furnace wall brick of a coke oven was measured with reference to Embodiment 1 of the present invention.

  At that time, a sensor box 11 having a size of 150 mm width × 140 mm height × 200 mm length on which the electromagnetic wave transmitting / receiving antenna 12 is mounted is manufactured, and the thickness of the coke oven furnace wall brick is about 1000 ° C. hot. It was measured. The measured brick was later removed from the coke oven and the thickness was confirmed to be 69 mm. Table 1 shows measurement conditions and measurement results.

  First, in condition 1, the sensor box 11 (antenna 12) was measured 4 mm away from the brick 13 for measurement. The thickness of the brick 13 was calculated using the refractive index, that is, the propagation speed of the electromagnetic wave, at a room temperature.

  In condition 2, as in condition 1, the sensor box 11 (antenna 12) was measured 4 mm away from the brick 13, and the thickness was calculated using the refractive index value at 1000 ° C.

  Further, in condition 3, as in condition 1, the sensor box 11 (antenna 12) is separated from the brick 13 by 4 mm, and between the sensor box 11 (antenna 12) and the brick 13, the heat resistant material 16 has a heat resistance of 1200 ° C. Measurement was made by filling a ceramic cloth of 4 mm. Refractive index calibration with temperature was also performed.

  The measurement results (measurement waveforms) under conditions 1 to 3 are shown in FIG. In this measurement, since the reflected wave returns at the boundary between the brick and the air, since the refractive index of air is lower than that of the brick, the intensity of the reflected wave is detected on the minus side.

  First, in condition 1, it was able to measure with 63 mm. The error was measured within 10% for a true value of 69 mm. Note that when the distance between the sensor box 11 (antenna 12) and the brick 13 was gradually increased and the measurement was continued, the peak value of the reflected wave could not be discriminated when the distance exceeded 300 mm.

  Next, in condition 2, it could be measured as 70 mm, which is almost the same as the true value.

  Furthermore, even under condition 3, it was possible to measure 70 mm, which is almost the same as the true value. In addition, while gradually increasing the distance between the sensor box 11 (antenna 12) and the brick 13 and gradually increasing the thickness of the heat insulating material 16 to be filled, if the thickness of the heat insulating material 16 exceeds 300 mm, the reflection is reflected. The peak value of the wave can no longer be determined.

  As can be seen from this Example 1, it is desirable that the brick thickness can be measured by electromagnetic waves, the temperature of the refractive index should be calibrated, and a distance of 4 to 300 mm between the sensor box 11 (antenna 12) and the brick 13. It was shown that the heat insulating layer 16 may be filled between the sensor box 11 (antenna 12) and the brick 13.

  As Example 2 of the present invention, the thickness of the furnace wall brick of the coke oven was measured with reference to Embodiment 1 of the present invention.

  At that time, a sensor box 11 having a size of 150 mm width × 140 mm height × 200 mm length on which the electromagnetic wave transmitting / receiving antenna 12 is mounted is manufactured, and the thickness of the coke oven furnace wall brick is about 1000 ° C. hot. It was measured. The measured brick was later removed from the coke oven and the thickness was confirmed to be 69 mm. Table 2 shows measurement conditions and measurement results.

  First, in condition 4a, measurement was performed by separating the sensor box 11 (antenna 12) from the brick 13 by 4 mm, and in condition 4b, measurement was performed by separating the sensor box 11 (antenna 12) from the brick 13 by 300 mm.

  In condition 5a, as in condition 4a, the sensor box 11 (antenna 12) is separated from the brick 13 by 4 mm, and a ceramic cloth 4 mm having a heat resistant temperature of 1200 ° C. is filled between the sensor box 11 (antenna 12) and the brick 13. In the condition 5b, the sensor box 11 (antenna 12) is separated from the brick 13 by 300 mm as in the condition 4b, and a ceramic cloth having a heat resistant temperature of 1200 ° C. between the sensor box 11 (antenna 12) and the brick 13 is measured. Measurement was performed by filling 300 mm.

  In all cases of conditions 4a, 4b, 5a, and 5b, the refractive index was calibrated with temperature.

  As a result, it was measured as 70 mm under condition 4a, and as 114 mm under condition 4b. And, as described above, when there is a space between the sensor box 11 (antenna 12) and the brick 13, it has been known that correction should be made by subtracting 0.15 times the spatial distance δ from the measured value. Condition 4a was corrected to be 70−4 × 0.15 = 69.4 mm, and condition 4b was 114−300 × 0.15 = 69 mm.

  Moreover, in condition 5a, it measured with 70 mm, and in condition 5b, it measured with 144 mm. And as mentioned above, when the heat insulating material (ceramic cloth) 16 is filled between the sensor box 11 (antenna 12) and the brick 13, the correction is made by subtracting 0.25 times the thickness δ of the ceramic cloth from the measured value. Therefore, it was found that 70-4 × 0.25 = 69 mm under condition 5a and 144−300 × 0.25 = 69 mm under condition 5b.

  As can be seen in the second embodiment, when there is a space or a heat insulating layer (heat insulating material) 16 between the sensor box 11 (antenna 12) and the brick 13, it is necessary to make a correction according to the material and thickness. It was shown that.

  As Example 3 of the present invention, the thickness of the furnace wall brick of the smelting furnace was measured with reference to Embodiment 2 of the present invention.

  At that time, a sensor box 11 having a size of 150 mm width × 140 mm height × 200 mm length on which the electromagnetic wave transmitting / receiving antenna 12 is mounted is manufactured, and a slag line iron skin 15 that is thinned in a refining furnace is 150 mm wide × The opening was 200 mm long, the sensor box 11 was attached, and the brick thickness was measured hot at about 1000 ° C. The measured brick was later removed from the smelting furnace and the thickness was confirmed to be 295 mm.

  Table 3 shows the measurement conditions and measurement results.

  First, in condition 6, the sensor box 11 (antenna 12) was measured 4 mm away from the brick 13. Refractive index calculated thickness using the value in normal temperature.

  In condition 7, as in condition 6, the sensor box 11 (antenna 12) was measured 4 mm away from the brick 13, and the thickness was calculated using the refractive index value at 1000 ° C.

  In condition 8, as in condition 6, the sensor box 11 (antenna 12) was measured 4 mm away from the brick 13 and then measured between the sensor box 11 (antenna 12) and the brick 13 and the ceramic cloth 16 having a heat resistant temperature of 1200 ° C. Was measured by filling 4 mm. Refractive index calibration with temperature was also performed.

  As a result, first, under condition 6, it could be measured as 272 mm. The error could be measured within 10% against the true value of 295 mm. Note that when the distance between the sensor box 11 (antenna 12) and the brick 13 was gradually increased and the measurement was continued, the peak value of the reflected wave could not be discriminated when the distance exceeded 300 mm.

  In condition 7, the thickness was calculated using the refractive index at 1000 ° C., so that the measurement was performed at 296 mm, which was almost the same as the true value.

  In condition 8, the heat insulation layer (ceramic cloth) 16 was filled 4 mm between the sensor box 11 (antenna 12) and the brick 13, and the refractive index was calibrated by temperature. did it. In addition, while gradually increasing the distance between the sensor box 11 (antenna 12) and the brick 13 and gradually increasing the thickness of the heat insulating material 16, when the thickness of the heat insulating material 16 exceeds 300 mm, The peak value can no longer be determined.

  As can be seen in Example 3, even in the case of a furnace in which a brick is stuck inside the iron skin container, such as a refining furnace, it is possible to measure the thickness of the brick by electromagnetic waves, and temperature calibration of the refractive index. It is preferable that a distance of 4 to 300 mm be provided between the sensor box 11 (antenna 12) and the brick 13, and a heat insulating layer 16 is filled between the sensor box (antenna 12) and the brick 13. Also shown to be good.

  As Example 4 of this invention, with reference to said Embodiment 2 of this invention, the thickness measurement of the furnace wall brick of a smelting furnace was performed.

  At that time, a sensor box 11 having a size of 150 mm width × 140 mm height × 200 mm length on which the electromagnetic wave transmitting / receiving antenna 12 is mounted is manufactured, and a slag line iron skin 15 that is thinned in a refining furnace is 150 mm wide × The opening was 200 mm long, the sensor box 11 was attached, and the brick thickness was measured hot at about 1000 ° C. The measured brick was later removed from the smelting furnace and the thickness was confirmed to be 295 mm.

  Table 4 shows the measurement conditions and measurement results.

  First, in condition 9a, the sensor box 11 (antenna 12) was measured 4 mm away from the brick 13 and in condition 9b, the sensor box 11 (antenna 12) was measured 300 mm away from the brick 13.

  In condition 10a, as in condition 9a, the sensor box 11 (antenna 12) is separated from the brick 13 by 4 mm, and a ceramic cloth 4 mm having a heat resistant temperature of 1200 ° C. is filled between the sensor box 11 (antenna 12) and the brick 13. In condition 10b, the sensor box 11 (antenna 12) is separated from the brick 13 by 300 mm as in the condition 9b, and a ceramic cloth having a heat resistant temperature of 1200 ° C. is interposed between the sensor box 11 (antenna 12) and the brick 13. Measurements were taken across 300 mm.

  In all cases of conditions 9a, 9b, 10a, and 10b, the refractive index was calibrated with temperature.

  As a result, it was measured as 296 mm under condition 9a, and as 340 mm under condition 9b. And, as described above, when there is a space between the sensor box 11 (antenna 12) and the brick 13, it has been known that correction should be made by subtracting 0.15 times the spatial distance δ from the measured value. Condition 9a was corrected to 296-4 × 0.15 = 295.4 mm, and condition 9b was corrected to 340−300 × 0.15 = 295 mm.

  Further, it was measured as 296 mm under the condition 10a, and as 370 mm under the condition 10b. And as mentioned above, when the heat insulating material (ceramic cloth) 16 is filled between the sensor box 11 (antenna 12) and the brick 13, the correction is made by subtracting 0.25 times the thickness δ of the ceramic cloth from the measured value. Since it was known that it was sufficient to perform the above, it was possible to correct the condition 10a to 296-4 × 0.25 = 295 mm and the condition 10b to 370−300 × 0.25 = 295 mm.

  As can be seen from the fourth embodiment, when there is a space or a heat insulating layer (heat insulating material) 16 between the sensor box 11 (antenna 12) and the brick 13, it is necessary to perform correction according to the material and thickness. It was shown that.

DESCRIPTION OF SYMBOLS 1 Carbonization chamber 2 Combustion chamber 3 Extruder 3a Ram 4 Furnace wall 5 Binder 6 Combustion chamber flue 7 Charcoal vehicle 8 Charging hole 11 Brick thickness measuring device (sensor box)
12 Antenna (transmit / receive antenna)
13 Brick 14 Member made of a material having a refractive index different from that of brick 15 Member made of a material that does not transmit electromagnetic waves such as an iron skin 16 Heat insulation layer 17 Opening

Claims (3)

  The time from when the electromagnetic wave is radiated from the transmitting antenna to the brick, the reflection of the electromagnetic wave at the boundary surface of the material with different refractive index is received by the receiving antenna, and the electromagnetic wave is reflected at the back of the brick and returns to the receiving antenna And a brick thickness measurement method, wherein a heat insulating layer having a thickness of 4 to 300 mm is filled between the transmitting antenna and the receiving antenna and the brick.   The brick thickness measuring method according to claim 1, wherein the thickness of the brick is corrected according to the thickness of the heat insulating layer filled between the transmitting antenna and the receiving antenna and the brick.   The brick thickness measuring method according to claim 1 or 2, wherein a material that does not transmit electromagnetic waves is opened when a brick whose thickness is to be measured is located inside a material that does not transmit electromagnetic waves.

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