JP2005265456A - Wall thickness measuring device and method of high-temperature tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wall thickness measuring device and a method of a high-temperature tank capable of measuring the wall thickness (namely, thickness reduction) in a wide range of the high-temperature tank in a short time without peeling an insulating material of the high-temperature tank (oven), and measuring accurately the actual wall thickness (namely, the thickness reduction) excluding an alloy layer even when the hard alloy layer is formed on the inner surface of the high-temperature tank and the apparent wall thickness is increased. <P>SOLUTION: This device is equipped with a high-temperature ultrasonic sensor for emitting an ultrasonic wave at a higher temperature than high-temperature liquid and capable of detecting its reflected wave, a sensor holding fixture for dipping directly the high-temperature ultrasonic sensor into the high-temperature liquid and holding its test surface toward the wall inner surface of a part to be measured, and a waveform analysis device for analyzing the waveform of the reflected wave detected by the high-temperature ultrasonic sensor and calculating the wall thickness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for measuring a wall thickness of a high-temperature tank used for hot dipping and the like.

Hot dipping is a plating means for forming a coating layer by immersing a material to be processed in molten metal and solidifying the molten metal adhering to the surface by solidification. The material is mainly steel, and the plating metal is zinc (melting point: about 420 ° C), tin (same: about 232 ° C), aluminum (same: about 660 ° C), lead (same: about 328 ° C), etc. Is used.
A side wall of a high-temperature bath (generally called a kettle) used for such hot dipping is made of a metal (for example, iron) having a melting point higher than that of the molten metal. However, since the side wall of the high-temperature tank gradually becomes thinner as a result of long-term use, it has been strongly demanded to measure this periodically and appropriately determine the time for replacing the pot.

Ultrasonic testing (UT), which is one of the nondestructive inspection methods, is widely used for inspection of internal defects and the like, and this is used to measure the thinning amount of a high-temperature pipe from the outside of the pipe. Means are disclosed in Patent Document 2.
Further, Patent Literature 1 is disclosed as a probe for an ultrasonic flaw detection test that can increase the allowable heat-resistant limit temperature to 550 to 600 ° C.

  As shown in FIG. 6, the “probe of an ultrasonic flaw detector” in Patent Document 1 is a vibration sandwiched between a pair of electrodes 56 a and 56 b on an ultrasonic transmission member 54 attached to a flaw detection object 51. In the probe 52 of the ultrasonic flaw detector formed by laminating the elements 55, the vibrator 55 is formed of lithium niobate, and these are directly placed between the vibrator 55 and the ultrasonic transmission member 54 in an aluminum system. An aluminum-based heat-resistant electrode layer A is formed by bonding with a brazing material, and this is used as an electrode. In this figure, reference numeral 53 denotes a contact medium.

  As shown in FIG. 7, the “Method and apparatus for attaching an ultrasonic sensor to a high-temperature structure” in Patent Document 2 is configured such that the tip surface of the sensor head 62 a of the ultrasonic sensor 62 is softly attached to the surface of the high-temperature structure 61. The ultrasonic sensor 62 is placed in a state in which the soft buffer metal plate 69 is plastically deformed and brought into close contact by pressing the sensor head 62a toward the surface of the high temperature structure 1 after being placed in contact with the buffer metal plate 69. Attached.

Japanese Examined Patent Publication No. 07-46095, “Probe for ultrasonic flaw detector” Japanese Patent Application Laid-Open No. 11-304777, “Method and apparatus for attaching an ultrasonic sensor to a high-temperature structure”

As mentioned above, the side walls of high-temperature tanks (pots) used for hot dipping, etc., gradually become thin with long-term use. Has been strongly demanded.
In order to satisfy this demand, it is possible in principle to measure the thinning amount from the outside of the high-temperature tank using the means disclosed in Patent Document 2. However, since the outside of the high-temperature bath (pot) is usually covered with a thick heat insulating material, it is necessary to peel off the heat insulating material to measure the wall thickness. There was a problem that it was practically impossible to measure a wide range of wall thickness (namely, thinning amount) of the high-temperature bath.
For this reason, a slender bar (palpation bar) is inserted into the tank from the top of the high-temperature tank and its lower end is brought into contact with the inner surface. It was not possible to accurately determine the replacement period.
Furthermore, as in the case of galvanization, when the molten metal and the metal constituting the side wall (for example, iron) form an alloy, a hard alloy layer is formed on the inner surface of the high-temperature tank, and the apparent wall thickness is increased. Judging with a palpation stick, the amount of thinning was underestimated, and there was even a risk of missing the pot replacement time.
Therefore, accurate measurement of the wall thickness (that is, the amount of thinning) of the high-temperature tank (kettle) has been a technology close to a dream until now.

The present invention has been developed to solve such a demand. That is, the first object of the present invention is to provide a high-temperature tank capable of measuring a wide range of wall thicknesses (that is, thickness reduction) in a short time without peeling off the heat insulation material of the high-temperature tank (kettle). It is to provide a wall thickness measuring method and apparatus.
The second purpose is to accurately measure the actual wall thickness excluding the alloy layer (that is, the amount of thinning) even when a hard alloy layer is formed on the inner surface of the high-temperature bath and the apparent wall thickness is increased. An object of the present invention is to provide an apparatus and method for measuring the wall thickness of a high-temperature vessel.

According to the present invention, a wall thickness measuring device for measuring the wall thickness of a high-temperature tank having a high-temperature liquid therein,
An ultrasonic sensor for high temperature capable of emitting an ultrasonic wave at a temperature higher than that of the high temperature liquid and detecting the reflected wave;
A sensor holder that directly immerses the high-temperature ultrasonic sensor in the high-temperature liquid and holds the flaw detection surface toward the wall inner surface of the measurement target part; and
There is provided a wall thickness measuring apparatus for a high-temperature tank, comprising: a waveform analyzing apparatus that analyzes a waveform of a reflected wave detected by a high-temperature ultrasonic sensor and calculates a wall thickness.

Moreover, according to the present invention, a wall thickness measuring method for measuring the wall thickness of a high-temperature tank having a high-temperature liquid therein,
A sensor holding step for directly immersing the ultrasonic sensor for high temperature in the high temperature liquid and holding the flaw detection surface toward the wall inner surface of the measurement target part;
There is provided a method for measuring a wall thickness of a high-temperature tank, comprising: a waveform analysis step for analyzing a waveform of a reflected wave detected by a high-temperature ultrasonic sensor and calculating a wall thickness.

According to the apparatus and method of the present invention described above, in the sensor holding step using the sensor holder, the high-temperature ultrasonic sensor is directly immersed in the high-temperature liquid, and the flaw detection surface is held toward the wall inner surface of the measurement target portion. Therefore, without peeling off the heat insulation material of the high-temperature tank (kettle), ultrasonic waves are emitted in the high-temperature liquid, the ultrasonic waves are propagated through the wall inner surface into the wall of the high-temperature tank, and the reflected wave reflected from the outer surface of the wall is detected by the sensor. Can be detected.
Moreover, since the waveform analysis step analyzes the waveform of the reflected wave detected and calculates the wall thickness in the waveform analysis step, it is possible to measure the wall thickness (that is, the thickness reduction) in a wide range of the high-temperature tank in a short time. .

According to a preferred embodiment of the present invention, in the waveform analysis step, the first reflected wave B1 from the wall outer surface and the second second reflected wave that is re-reflected by the wall inner surface and the wall outer surface in the waveform analysis step. B2 is detected, and the wall thickness is calculated from the time difference and the ultrasonic wave propagation velocity.
By this means, the first reflected wave B1 and the second reflected wave B2 can be detected with a high S / N ratio, and the temperature of the wall material (for example, iron) constituting the high-temperature tank (for example, the speed of ultrasonic propagation (that is, the speed of sound)). The wall thickness can be easily calculated from the relationship.

In the waveform analysis step, it is preferable that the waveform of the reflected wave detected is frequency-analyzed and the alloy reflected wave G1 is identified from the noise echo in the waveform analysis step.
By this means, even when the S / N ratio of the alloy reflected wave G1 is low, the alloy reflected wave G1 can be identified from the noise echo. Therefore, even when a hard alloy layer is formed on the inner surface of the high-temperature tank and the apparent wall thickness is increased, the actual wall thickness (that is, the amount of thinning) excluding the alloy layer can be accurately measured.

In addition, in the waveform analysis step, the waveform analysis apparatus detects the alloy reflected wave G1 in which the first reflected wave B1 is re-reflected at the alloy layer interface and the wall outer surface, and the time difference between the second reflected wave B2 and the alloy reflected wave G1 is detected. The wall thickness is corrected.
By this means, the thickness of the alloy layer can be easily calculated from the relationship between the composition of the alloy layer growing on the inner surface of the high-temperature tank (for example, Zn—Fe) and its temperature-ultrasonic propagation velocity (ie, sound velocity).

According to a preferred embodiment of the present invention, the high-temperature ultrasonic sensor includes an ultrasonic transducer, a pair of electrode plates brazed with the ultrasonic transducer interposed therebetween, and a wetted high-temperature liquid brazed to one of the electrodes. It consists of a shoe plate with high characteristics,
Signal lines are directly attached to the electrodes, and the flaw detection surface of the shoe plate is plated with high wettability of high temperature liquid.
With this configuration, the heat resistance temperature of the entire sensor when the ultrasonic sensor for high temperature is directly immersed in the high-temperature liquid can be increased, the wettability of the high-temperature liquid on the flaw detection surface can be increased, and the ultrasonic transmission can be increased. Can do.

The sensor holder includes a vertical bar member that holds a high-temperature ultrasonic sensor at a lower end and extends upward, and the vertical bar member is suspended so as to be swingable about a horizontal axis, and can be attached to an upper portion of a high-temperature tank. A lower holding member.
With this configuration, the suspended holding member is attached to the upper part of the high-temperature tank, the vertical bar member is suspended from the suspended holding member, and the vertical bar member is swung around the horizontal axis to maintain the high temperature held at the lower end. The ultrasonic sensor can be pressed toward the wall inner surface of the measured part or held at a predetermined interval.

It is preferable that the vertical bar member has a counterweight and dross intrusion prevention block for reducing buoyancy due to the high-temperature liquid.
With this counterweight / dross intrusion prevention block, the buoyancy of the vertical bar member due to the high-temperature liquid can be reduced or eliminated, and the position of the high-temperature ultrasonic sensor can be easily changed.

The vertical bar member preferably has a positioning member for positioning the flaw detection surface of the high-temperature ultrasonic sensor toward the wall inner surface at a certain distance.
With this configuration, the flaw detection surface of the high-temperature ultrasonic sensor can be positioned at a certain distance toward the wall inner surface simply by pressing the positioning member toward the wall inner surface.

  As described above, the apparatus and method for measuring the wall thickness of a high-temperature tank according to the present invention can increase the wall thickness (that is, the amount of thinning) in a wide range of the high-temperature tank in a short time without peeling off the heat insulating material of the high-temperature tank (kettle). Even if a hard alloy layer is formed on the inner surface of the high-temperature bath and the apparent wall thickness is increasing, the actual wall thickness excluding the alloy layer (that is, the amount of thinning) can be accurately measured. It has excellent effects such as being able to.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1A is an overall configuration diagram of a wall thickness measuring apparatus for a high-temperature tank according to the present invention. In this example, the high temperature liquid 1 is molten zinc and is maintained in a molten state of about 450 ° C. Moreover, the high temperature tank 2 is a high temperature tank for hot dipping, and is made of iron in this example. The wall thickness measuring apparatus 10 according to the present invention is an apparatus for measuring the wall thickness of a hot bath 2 for hot dipping that contains a high temperature liquid 1 therein.
When the alloy layer 3 grows on the inner surface of the high-temperature tank 2, the inner surface 2a of the high-temperature tank 2 is apparently thicker by the amount of the alloy layer. In this case, the interface of the alloy layer is 3a.

  The wall thickness measurement apparatus 10 of the present invention includes a high-temperature ultrasonic sensor 12, a sensor holder 20, and a waveform analysis apparatus 30.

  The high-temperature ultrasonic sensor 12 has a function of emitting an ultrasonic wave at a temperature higher than that of the high-temperature liquid 1 and detecting the reflected wave. As shown in FIG. 1B, the high-temperature ultrasonic sensor 12 includes an ultrasonic transducer 13, a pair of electrode plates 14 brazed with the ultrasonic transducer 13, and a wettability of a high-temperature liquid brazed to one of them. And a high shoe plate 15. Further, the signal wire 16 (in this example, a platinum lead wire) is directly attached to the electrode 14, and the flaw detection surface 15a of the shoe plate 15 is plated with high wettability plating 17 (in this example, zinc plating). . In this case, brazing and direct soldering use a brazing material (for example, nickel) having a melting point higher than that of the high-temperature liquid. The high temperature ultrasonic sensor 12 is preferably housed entirely in a watertight container. The signal line 16 transmits detection data to the waveform analysis device 30 through the heat-resistant protective tube 18. Furthermore, it is preferable that the high-temperature ultrasonic sensor 12 is provided with a thermocouple and the temperature of the high-temperature liquid 1 is measured.

The sensor holder 20 has a function of directly immersing the high-temperature ultrasonic sensor 12 in the high-temperature liquid 1 and holding the flaw detection surface 15a toward the wall inner surface 2a of the measured portion.
In this example, the sensor holder 20 includes a vertical bar member 22 and a suspended holding member 24. The vertical bar member 22 is an elongated bar member that holds the high-temperature ultrasonic sensor 12 at the lower end and extends upward, and is made of, for example, a stainless angle material. The suspension holding member 24 suspends the vertical bar member 22 so as to be swingable about a horizontal axis 23, and is attached to the upper portion (for example, the upper end portion of the wall) of the high-temperature tank with a fixture 25 such as a bolt.

In this example, a counterweight / dross intrusion prevention block 21 is attached to the lower end of the vertical bar member 22 to reduce buoyancy due to the high-temperature liquid 1.
The vertical bar member 22 has a positioning member 26 for positioning the flaw detection surface 15a of the high-temperature ultrasonic sensor 12 toward the wall inner surface 2a at a certain distance. In this example, the positioning member 26 is three bars (only two are shown in the figure) arranged so as to surround the high-temperature ultrasonic sensor 12, and a plane passing through the tip (right end in the figure) It is set to coincide with the surface 15a or separated by a certain distance.
With this configuration, the flaw detection surface 15a of the high-temperature ultrasonic sensor 12 can be positioned at a certain distance toward the wall inner surface simply by pressing the tip of the positioning member 26 toward the wall inner surface 2a.

  The waveform analyzer 30 includes a power source, a storage device, an arithmetic device, and the like for the ultrasonic sensor, and analyzes the waveform of the reflected wave detected by the high-temperature ultrasonic sensor 12 to calculate the wall thickness.

FIG. 2 is an overall flowchart of the method for measuring the wall thickness of the high-temperature tank of the present invention. As shown in this figure, the wall thickness measuring method of the present invention comprises a sensor holding step S1 and a waveform analyzing step S2.
In the sensor holding step S1, the high-temperature ultrasonic sensor 12 is directly immersed in the high-temperature liquid 1 using the sensor holder 20 described above, and the flaw detection surface 15a is held toward the wall inner surface 2a of the measurement target portion.
In the waveform analysis step S2, the waveform of the reflected wave detected by the high temperature ultrasonic sensor 12 is analyzed to calculate the wall thickness.

In this example, the waveform analysis step S2 includes a wall thickness calculation step S21, an alloy layer identification step S22, and a wall thickness correction step S23.
In the wall thickness calculation step S21, the first first reflected wave B1 from the wall outer surface and the second second reflected wave B2 reflected again by the wall inner surface and the wall outer surface are detected, and the time difference and the ultrasonic wave propagation speed are detected. Calculate the wall thickness.
In the alloy layer identification step S22, the detected reflected wave waveform is frequency-analyzed to identify the alloy reflected wave G1 from the noise echo.
In the wall thickness correction step S23, the alloy reflected wave G1 that is reflected again by the first reflected wave B1 at the alloy layer interface and the wall outer surface is detected, and the wall thickness is corrected by the time difference between the second reflected wave B2 and the alloy reflected wave G1. .

  FIG. 3 is a diagram showing a first embodiment of the present invention. In this figure, (A) is a schematic view when the alloy layer does not grow or can be ignored, and (B) is a detected reflected wave (echo) detected. 3B, the horizontal axis represents time, the vertical axis represents the waveform of the reflected wave sound pressure, and the echo has a waveform that oscillates up and down around zero.

3A and 3B, B1 is the first first reflected wave from the outer wall surface, and B2 is the second reflected wave for the second time when the first reflected wave is re-reflected by the inner wall surface and the outer wall surface.
As apparent from FIG. 3B, the detected reflected wave (echo) immediately after emitting the ultrasonic wave has a large fluctuation and it is difficult to identify the reflected wave from the inner surface of the wall, whereas the first reflected wave B1 The second reflected wave B2 has a relatively high S / N ratio and can be easily detected. Therefore, in the wall thickness calculation step S21, the first first reflected wave B1 from the wall outer surface and the second second reflected wave B2 reflected again by the wall inner surface and the wall outer surface are detected, and the time difference Δt1 and the wall ( The wall thickness L1 can be calculated from, for example, L1 = v1 × Δt1 / 2 (Equation 1) from the ultrasonic wave propagation velocity v1 in (iron).
When the alloy layer does not grow or can be ignored, the value obtained by Equation 1 is the wall thickness L1 of the measured portion, and the difference ΔL from the thickness at the time of new installation is the thickness reduction.

  FIG. 4 is a diagram showing a second embodiment of the present invention. In this figure, (A) is a schematic view when the alloy layer cannot be ignored, and (B) is a detected reflected wave (echo) detected. 4B, similarly to FIG. 3B, the horizontal axis represents time, and the vertical axis represents the waveform of the reflected wave sound pressure.

When the alloy layer 3 cannot be ignored, the alloy reflected wave G1 shown in FIG. 4B, that is, the alloy reflected wave G1 in which the first reflected wave B1 is re-reflected at the alloy layer interface 3a and the outer wall surface has a small S / N ratio and is generated from noise echo. Is difficult to identify.
Therefore, in this case, in the alloy layer identifying step S22, the detected reflected wave waveform is subjected to frequency analysis, and the alloy reflected wave G1 is identified from the noise echo. 4B, when the frequency analysis of the waveform before the second reflected wave B2 is performed with a narrow time width, if it is a noise echo, it shows an unstable peak frequency, and the echo at the alloy interface In this case, a stable peak frequency (for example, a value close to the natural frequency of the ultrasonic sensor) is shown. Therefore, the alloy reflected wave G1 can be identified from the noise echo by gradually changing the frequency analysis position.

In FIG. 4A, the time difference Δt2 between the second reflected wave B2 and the alloy reflected wave G1 is the time for the ultrasonic wave to pass through the alloy layer once. Therefore, in the wall thickness correction step S23, the alloy reflected wave G1 that is reflected again by the first reflected wave B1 at the alloy layer interface and the wall outer surface is detected, and a time difference Δt2 between the second reflected wave B2 and the alloy reflected wave G1 is obtained. The wall thickness L1 obtained in the wall thickness calculation step S21 is corrected with the time difference Δt2.
For example, L2 = v1 × (Δt1−Δt2) / 2 (Equation 2) can be calculated, and the difference ΔL from the thickness at the time of new installation is the amount of thinning.

FIG. 5 shows the wall thickness measurement results obtained in Examples 1 and 2 of the present invention. In this figure, the horizontal axis is the wall thickness of the high-temperature tank, and the vertical axis is the depth (liquid depth). Further, Δ and ○ in the figure are the results of Example 1 in which the alloy layer is ignored, and □ are the results of Example 2 in which the alloy layer is corrected.
This example is the result of measuring the wall thickness of molten zinc (about 450 ° C.) made of iron.

  From the results of Example 1 in FIG. 5, the wall thickness (that is, the amount of thinning) in a wide range of the high-temperature tank is measured in a short time without peeling off the heat insulating material of the high-temperature tank (kettle) by the apparatus and method of the present invention. Confirmed that you can.

  However, the wall thickness made of iron was 60 mm when newly installed, and from the results of Example 1, it was newly revealed from Example 1 that an alloy layer was formed on the inner surface. Therefore, the position of the alloy layer interface 3a was detected according to Example 2 described above, and the correction was made accordingly. As a result, as shown in Example 2 of FIG. 5, the thickness of the alloy layer has reached about 5 to 6 mm, the true value of the wall thickness is about 58 mm, and the thickness reduction is about 2 mm from the time of new installation. I found out that

As described above, according to the present invention, compared with a qualitative measurement method that relies on the conventional human sense, the amount of thinning can be measured quantitatively, and the life of the plating pot can be accurately predicted. become.
Further, since the platinum lead wire is directly attached to the high-temperature ultrasonic sensor, it can be measured by being immersed in molten zinc at about 450 ° C. without cooling.
As a result, in the above examples, no deterioration in the sensor performance was observed even after continuous use for a long time (about 7 hours).
In addition, by making the shoe material of the ultrasonic sensor for high temperature iron and galvanizing the flaw detection surface in advance, the ultrasonic permeability to molten zinc is increased and the thickness can be measured.
In addition, in the case of ultrasonic wall thickness measurement, the sound speed varies depending on the temperature of the object to be measured, and the apparent wall thickness value increases, but the relationship between the temperature of Fe and the sound speed is obtained, and a temperature / sound speed table is created to create the sound speed. By performing the correction, the correct wall thickness could be measured.
Furthermore, the relationship between the temperature of the Zn-Fe alloy and the speed of sound is obtained, the temperature / sound speed table is created and the speed of sound is corrected, and the thickness of the pot body is correctly determined by subtracting the thickness of the alloy layer from the measured thickness. did it.

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

It is a whole block diagram of the wall thickness measuring apparatus of the high temperature tank of this invention. It is a whole flowchart of the wall thickness measuring method of the high temperature tank of this invention. It is a detection reflected wave (echo) in 1st Example of this invention. It is a detection reflected wave (echo) in 2nd Example of this invention. It is the wall thickness measurement result obtained in the Example of this invention. 6 is a schematic diagram of “a probe of an ultrasonic flaw detector” in Patent Document 1. FIG. 10 is a schematic diagram of “Method and apparatus for attaching ultrasonic sensor to high-temperature structure” in Patent Document 2. FIG.

Explanation of symbols

1 high temperature liquid, 2 high temperature bath, 2a wall inner surface, 3 alloy layer, 3a alloy layer interface,
10 Wall thickness measuring device, 12 High temperature ultrasonic sensor,
13 ultrasonic transducer, 14 electrode plate, 15 shoe plate, 15a flaw detection surface,
16 signal wire (platinum lead wire), 17 plating, 18 protective tube,
20 sensor holder, 21 counterweight and dross prevention block,
22 vertical bar member, 23 horizontal axis,
24 suspension holding member, 25 fixture, 26 positioning member, 30 waveform analyzer

Claims (12)

A wall thickness measuring device for measuring the wall thickness of a high-temperature tank having a high-temperature liquid therein,
An ultrasonic sensor for high temperature capable of emitting an ultrasonic wave at a temperature higher than that of the high temperature liquid and detecting the reflected wave;
A sensor holder that directly immerses the high-temperature ultrasonic sensor in the high-temperature liquid and holds the flaw detection surface toward the wall inner surface of the measurement target part; and
A wall thickness measuring apparatus for a high-temperature tank, comprising: a waveform analyzing apparatus that analyzes a waveform of a reflected wave detected by an ultrasonic sensor for high temperature and calculates a wall thickness.   The waveform analysis apparatus detects the first reflected wave B1 from the outer wall surface and the second reflected wave B2 which is reflected again by the inner wall surface and the outer wall surface, and determines the wall from the time difference and the ultrasonic propagation velocity. The apparatus for measuring a wall thickness of a high-temperature tank according to claim 1, wherein the thickness is calculated.   The apparatus for measuring a wall thickness of a high-temperature tank according to claim 1, wherein the waveform analysis apparatus performs frequency analysis on the waveform of the detected reflected wave, and identifies the alloy reflected wave G1 from the noise echo.   The waveform analysis apparatus detects the alloy reflected wave G1 in which the first reflected wave B1 is re-reflected at the alloy layer interface and the wall outer surface, and corrects the wall thickness by the time difference between the second reflected wave B2 and the alloy reflected wave G1. The apparatus for measuring a wall thickness of a high-temperature tank according to claim 2. The high-temperature ultrasonic sensor comprises an ultrasonic transducer, a pair of electrode plates brazed with the ultrasonic transducer interposed therebetween, and a shoe plate brazed to one of them and having high wettability with high-temperature liquid,
The apparatus for measuring a wall thickness of a high-temperature tank according to claim 1, wherein a signal line is directly attached to the electrode, and the flaw detection surface of the shoe plate is plated with high wettability of high-temperature liquid.   The sensor holder includes a vertical bar member that holds a high-temperature ultrasonic sensor at a lower end and extends upward, and the vertical bar member is suspended so as to be swingable about a horizontal axis and can be attached to an upper portion of a high-temperature tank. The apparatus for measuring a wall thickness of a high-temperature tank according to claim 1, further comprising a lower holding member.   The wall thickness measuring device for a high-temperature tank according to claim 6, wherein the vertical bar member has a counterweight and dross intrusion prevention block for reducing buoyancy due to high-temperature liquid.   The wall thickness measurement of a high-temperature tank according to claim 6, wherein the vertical bar member has a positioning member for positioning the flaw detection surface of the high-temperature ultrasonic sensor toward the wall inner surface at a certain distance. apparatus. A wall thickness measurement method for measuring the wall thickness of a high-temperature tank having a high-temperature liquid therein,
A sensor holding step for directly immersing the ultrasonic sensor for high temperature in the high temperature liquid and holding the flaw detection surface toward the wall inner surface of the measurement target part;
A waveform analysis step of analyzing a waveform of a reflected wave detected by a high-temperature ultrasonic sensor and calculating a wall thickness, and a method for measuring a wall thickness of a high-temperature tank.   In the waveform analysis step, the first reflected wave B1 from the wall outer surface and the second second reflected wave B2 reflected again by the wall inner surface and the wall outer surface are detected, and the wall is determined from the time difference and the ultrasonic propagation velocity. The method for measuring the wall thickness of a high-temperature tank according to claim 9, wherein the thickness is calculated.   10. The method for measuring a wall thickness of a high-temperature tank according to 9, wherein, in the waveform analysis step, the detected reflected wave waveform is frequency-analyzed to identify the alloy reflected wave G1 from a noise echo. In the waveform analysis step, the first reflected wave B1 detects the alloy reflected wave G1 re-reflected at the alloy layer interface and the wall outer surface, and the wall thickness is corrected by the time difference between the second reflected wave B2 and the alloy reflected wave G1. The method for measuring a wall thickness of a high-temperature tank according to claim 10.

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