JP6912899B2 - Film thickness measurement method and film thickness measurement device - Google Patents

Description

The present disclosure relates to a film thickness measuring method for measuring the film thickness of a scale formed on the inner surface of a pipe by a probe arranged inside the pipe, and a film thickness measuring device.

For example, in the piping of a land boiler installed in a thermal power plant, the inner surface of the piping is steam-oxidized by aged use, and a steam oxidation scale (hereinafter referred to as scale) is formed on the inner surface of the piping. There is. If the film thickness of this scale is increased, heat transfer of the pipe may be hindered, an abnormal temperature gradient may be generated in the pipe, and pressure loss may be increased. Therefore, it is necessary to measure the film thickness of the scale.

As a method of measuring the film thickness of the scale, for example, in Patent Document 1, a probe is applied to the outer surface of the pipe from the outside of the pipe to emit ultrasonic waves, which are reflected at the boundary between the pipe and the scale (inner surface of the pipe). A technique for calculating the scale film thickness from the time difference between receiving the boundary surface echo to be performed and the surface echo reflected from the surface of the scale is disclosed.

Japanese Unexamined Patent Publication No. 10-253340

However, in the method of measuring the film thickness of the scale described in Patent Document 1, since the probe is applied to the outer surface of the pipe, a pretreatment for removing the outer surface scale formed on the outer surface of the pipe is performed. There is a need. Therefore, it is difficult to continuously measure the film thickness of the scale along the outer surface of the pipe. In addition, it may be difficult to hit the probe on the outer surface of the pipe because of the presence of metal fittings and intersections in the pipe.

Further, according to the findings of the present inventors, in the method of measuring the film thickness of the scale described in Patent Document 1, when the film thickness of the scale becomes thin, the time difference between the boundary surface echo and the surface echo becomes small. Therefore, it is difficult to separate the interface echo and the surface echo, and it has been found that the film thickness of the scale may not be calculated.

At least some embodiments of the present invention have been made in view of the above-mentioned problems, and a film thickness measuring method capable of continuously measuring the film thickness of the scale formed on the inner surface of the pipe from the inside of the pipe, and a film thickness measuring method. An object of the present invention is to provide a film thickness measuring device.

(1) The film thickness measuring method according to at least one embodiment of the present invention is a film thickness for measuring the film thickness of the scale formed on the inner surface of the pipe by a probe arranged inside the pipe. In the measurement method, an ultrasonic transmission step of transmitting ultrasonic waves from the inside of the pipe to the inner surface of the pipe by the probe and the ultrasonic waves incident on the surface of the scale of the pipe are used in the pipe. A first bottom surface echo reflected on the outer surface, which propagates through a first propagation path that repeatedly reciprocates from the outer surface of the pipe to the surface of the scale n times (where n is a natural number of 1 or more). The bottom surface echo is a first bottom surface echo receiving step in which the bottom surface echo is received by the probe, and a second bottom surface echo in which the ultrasonic waves incident on the surface of the scale are reflected by the outer surface of the pipe. The search for a second bottom surface echo that propagates through a second propagation path that reciprocates from the outer surface of the pipe to the inner surface of the pipe at least once and reflects the second bottom surface echo n times on the outer surface of the pipe. The second bottom surface echo receiving step received by the tentacle, the first propagation time when the first bottom surface echo was received by the probe in the first bottom surface echo receiving step, and the probe in the second bottom surface echo receiving step. It includes a film thickness calculation step of calculating the film thickness of the scale based on the difference from the second propagation time when the second bottom surface echo is received by the child.

According to the method (1) above, the film thickness of the scale formed on the inner surface of the pipe is measured by the probe arranged inside the pipe. Therefore, it is not necessary to perform pretreatment such as removing the outer surface scale formed on the outer surface of the pipe, and the film thickness of the scale can be continuously measured. In addition, even in places such as attached hardware or intersections where it is difficult to hit the probe on the outer surface of the pipe, the probe is placed inside the pipe, so the film thickness of the scale is measured. be able to.

Further, according to the method (1) above, the first bottom surface echo receiving step receives the first bottom surface echo propagating in the first propagation path, and the second bottom surface echo receiving step receives the second bottom surface echo propagating in the second propagation path. Receive bottom echo. The first propagation path reciprocates n times repeatedly from the outer surface of the pipe to the surface of the scale, and this second propagation path reciprocates at least once from the outer surface of the pipe to the inner surface of the pipe and the second. This is a path that reflects the bottom echo n times on the outer surface of the pipe. Therefore, the first propagation path is longer than the second propagation path so as to correspond to the length from the inner surface of the pipe to the surface of the scale (the size of the film thickness of the scale). Therefore, the film thickness of the scale can be calculated based on the difference between the first propagation time when the first bottom surface echo is received and the second propagation time when the second bottom surface echo is received.

Each of the first bottom surface echo and the second bottom surface echo has a large amplitude immediately after the start of reception, and the amplitude gradually decreases toward the completion of reception. Further, the amplitude of the first bottom surface echo is larger than the amplitude of the second bottom surface echo. According to the method (1) above, since the first propagation path is longer than the second propagation path, reception of the first bottom surface echo is started after the second bottom surface echo. Therefore, even if reception of the first bottom surface echo is started while the probe is receiving the second bottom surface echo, it becomes easy to separate the first bottom surface echo and the second bottom surface echo. Therefore, even if a scale having a thin film thickness is formed on the inner surface of the pipe, the film thickness of the scale can be calculated by the first bottom surface echo and the second bottom surface echo that can be easily separated.

(2) In some embodiments, in one method described in (1) above, a water immersion step of filling the inside of the pipe with water is further provided before the ultrasonic wave transmission step.

It is known that if ultrasonic waves are transmitted and received after the probe and the test piece are filled with water, the influence of the surface roughness of the test piece on the echo detection accuracy is reduced. According to the method (2) above, the space between the probe and the pipe is filled with water. Therefore, the film thickness of the scale can be easily measured as compared with the case where the space between the probe and the pipe is not filled with water.

(3) In some embodiments, in the method described in (1) or (2) above, the probe is placed in the radial direction of the main body with respect to the main body supporting the probe. Further provided with a radial movement step to move along.

According to the method (3) above, the probe can transmit and receive ultrasonic waves to the inner surface of the pipe by changing the radial length from the probe to the inner surface of the pipe. Therefore, the length from the probe to the inner surface of the pipe is optimized (the separability of the first bottom surface echo and the second bottom surface echo received by the probe is optimized, and the pipe from the probe is optimized. The radial length to the inner surface of the scale) and the film thickness of the scale can be measured.

(4) In some embodiments, in one of the methods (1) to (3) above, the pipe is constructed based on the film thickness of the scale calculated by the film thickness calculation step. A wall thickness calculation step for calculating the wall thickness is further provided.

According to the method (4) above, the film thickness of the scale formed on the inner surface of the pipe and the wall thickness of the pipe can be calculated at the same time.

(5) The film thickness measuring device according to at least one embodiment of the present invention is a film thickness measuring device for measuring the film thickness of the scale formed on the inner surface of the pipe from the inside of the pipe. The ultrasonic waves are configured to be able to be transmitted from the inside of the pipe toward the inner surface of the pipe, and the ultrasonic waves transmitted from the probe and incident on the surface of the scale are reflected by the outer surface of the pipe. The first bottom surface echo is a first bottom surface echo that propagates through a first propagation path that repeatedly reciprocates from the outer surface of the pipe to the surface of the scale n times (where n is a natural number of 1 or more). A second bottom surface echo in which the ultrasonic waves transmitted from the probe and incident on the surface of the scale are reflected on the outer surface of the pipe, from the outer surface of the pipe to the inner surface of the pipe. A film having a probe that reciprocates at least once and is configured to receive a second bottom surface echo that propagates on a second bottom surface echo that reflects the second bottom surface echo n times on the outer surface of the pipe. The scale is based on the difference between the thickness sensor and the first propagation time when the first bottom surface echo is received by the probe and the second propagation time when the second bottom surface echo is received by the probe. A controller capable of executing a film thickness calculation process for calculating the film thickness is provided.

According to the configuration of (5) above, the film thickness of the scale formed on the inner surface of the pipe is measured by the probe arranged inside the pipe. Therefore, it is not necessary to perform a pretreatment such as removing the outer surface scale formed on the outer surface of the pipe, and the film thickness of the scale can be measured. In addition, even in places such as attached hardware or intersections where it is difficult to apply the probe to the outer surface of the pipe, the probe is placed inside the pipe, so the film thickness of the scale can be easily increased. Can be measured.

Further, according to the configuration of (5) above, the film thickness sensor is configured to be able to receive the first bottom surface echo propagating in the first propagation path and the second bottom surface echo propagating in the second propagation path. Has a tentacle. The first propagation path reciprocates n times repeatedly from the outer surface of the pipe to the surface of the scale, and this second propagation path reciprocates at least once from the outer surface of the pipe to the inner surface of the pipe and the second. This is a path that reflects the bottom echo n times on the outer surface of the pipe. Therefore, the first propagation path is longer than the second propagation path so as to correspond to the length from the inner surface of the pipe to the surface of the scale. Therefore, the controller can calculate the film thickness of the scale based on the difference between the first propagation time when the first bottom surface echo is received and the second propagation time when the second bottom surface echo is received.

Each of the first bottom surface echo and the second bottom surface echo has a maximum peak immediately after the start of reception, and the peak gradually decreases toward the completion of reception. Further, the peak of the first bottom surface echo is larger than the peak of the second bottom surface echo. According to the configuration of (5) above, since the first propagation path is longer than the second propagation path, the reception of the first bottom surface echo is started after the second bottom surface echo. Therefore, even if the receiver starts receiving the first bottom surface echo while the probe is receiving the second bottom surface echo, it is easy to separate the first bottom surface echo and the second bottom surface echo. Therefore, even if a scale having a thin film thickness is formed on the inner surface of the pipe, the controller can calculate the film thickness of the scale by the first bottom surface echo and the second bottom surface echo that can be easily separated.

(6) In some embodiments, in the configuration described in (5) above, the film thickness sensor further has a main body portion that supports the probe, and the film thickness sensor is the main body portion. A first-row probe group consisting of a plurality of the probes arranged along the circumferential direction of the main body, and a second-row probe consisting of a plurality of the probes arranged along the circumferential direction of the main body. A group of tentacles, including the first row probe group and a second probe group adjacent to the first row probe group, the probe of the first row probe group, and the second row probe. The probes of the child group are arranged so as to be offset from each other in the circumferential direction.

According to the configuration of (6) above, the probe of the first row probe group and the probe of the second row probe group are displaced from each other in the circumferential direction (for example, in a staggered pattern). ) Are arranged. Therefore, by moving the main body in the direction orthogonal to the circumferential direction (axial direction), the range of the inner surface of the pipe where ultrasonic waves cannot be transmitted / received by the probes of the first row probe group. On the other hand, ultrasonic waves can be transmitted and received by the probes of the second row probe group. Therefore, the film thickness measuring device can measure the film thickness of the scale over the entire circumference of the inner surface of the pipe.

(7) In some embodiments, in one configuration according to (5) or (6) above, the film thickness sensor further has a main body that supports the probe, and the probe is , The position of the main body in the radial direction is variably configured.

According to the configuration of (7) above, the probe can transmit and receive ultrasonic waves to the inner surface of the pipe by changing the radial length from the probe to the inner surface of the pipe. Therefore, the film thickness measuring device can measure the film thickness of the scale by optimizing the radial length from the probe to the inner surface of the pipe.

(8) In some embodiments, in one configuration according to any one of (5) to (7) above, a rod-shaped member that can be inserted into the inside of the pipe and to which the film thickness sensor is attached. Further, a centering jig attached to the rod-shaped member at a position different from that of the film thickness sensor in the axial direction of the rod-shaped member is provided.

According to the configuration (8) above, the alignment jig attached to the rod-shaped member adjusts the inclination of the film thickness sensor with respect to the inner surface of the pipe, so that the first bottom surface echo and the first bottom surface echo received by the probe are received. 2 The signal level of the bottom echo can be improved.

According to at least one embodiment of the present invention, it is possible to provide a film thickness measuring method and a film thickness measuring device capable of continuously measuring the film thickness of the scale formed on the inner surface of the pipe from the inside of the pipe. ..

It is a schematic block diagram which shows the film thickness measuring apparatus which concerns on one Embodiment of this invention. It is a flowchart of the film thickness measurement method of the film thickness measuring apparatus which concerns on one Embodiment of this invention. It is a figure which showed the state of transmitting and receiving ultrasonic waves by the probe which concerns on one Embodiment of this invention. The detection waveforms of the surface echo and the boundary surface echo of FIG. 3A are shown. It is a figure which showed the state of transmitting and receiving ultrasonic waves by the probe which concerns on one Embodiment of this invention. The detection waveforms of the first primary reflection bottom echo, the second primary reflection bottom echo, and the third primary reflection surface echo of FIG. 4A are shown. It is a figure which showed the state of transmitting and receiving ultrasonic waves by the probe which concerns on one Embodiment of this invention. The detection waveforms of the first bottom surface echo, the second bottom surface echo, the third secondary reflection bottom surface echo, and the fourth secondary reflection bottom surface echo of FIG. 5A are shown. It is explanatory drawing for demonstrating the radial movement step of the film thickness measuring method which concerns on one Embodiment of this invention. It is a block diagram which shows the internal structure of the controller which concerns on one Embodiment of this invention.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, and are merely explanatory examples. do not have.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
Further, for example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also includes a concavo-convex portion or a concavo-convex portion within a range in which the same effect can be obtained. The shape including the chamfered portion and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 is a schematic configuration diagram showing a film thickness measuring device according to an embodiment of the present invention.

As shown in FIG. 1, the film thickness measuring device 1 is a device for measuring the film thickness of the scale 54 formed on the inner surface 52 of the pipe 50 from the inside 51 of the pipe 50. Such a film thickness measuring device 1 includes a film thickness sensor 2 including a main body portion 6 that supports a probe 4 arranged inside 51 of the pipe 50.

FIG. 2 is a flowchart of a film thickness measuring method of the film thickness measuring device according to the embodiment of the present invention. FIG. 3A is a diagram showing a state in which ultrasonic waves are transmitted and received by a probe according to an embodiment of the present invention. FIG. 3A (a) shows how a surface echo is received. FIG. 3A (b) shows how the interface echo is received. FIG. 3B shows the detection waveforms of the surface echo and the boundary surface echo of FIG. 3A. FIG. 4A is a diagram showing a state in which ultrasonic waves are transmitted and received by a probe according to an embodiment of the present invention. FIG. 4A (a) shows how the first primary reflection bottom echo is received. FIG. 4A (b) shows how the second primary reflection bottom echo is received. FIG. 4A (c) shows how the third primary reflection bottom echo is received. FIG. 4B shows the detection waveforms of the first primary reflection bottom echo, the second primary reflection bottom echo, and the third primary reflection surface echo of FIG. 4A. FIG. 5A is a diagram showing a state in which ultrasonic waves are transmitted and received by a probe according to an embodiment of the present invention. FIG. 5A (a) shows how the first secondary reflection bottom echo (first bottom echo) is received. FIG. 5A (b) shows how the second secondary reflection bottom echo (second bottom echo) is received. FIG. 5A (c) shows how the third secondary reflection bottom echo is received. FIG. 5A (d) shows how the fourth secondary reflection bottom echo is received. FIG. 5B shows the detection waveforms of the first bottom surface echo, the second bottom surface echo, the third secondary reflection bottom surface echo, and the fourth secondary reflection bottom surface echo of FIG. 5A.

In the film thickness measuring method according to the embodiment of the present invention, the film thickness of the scale 54 formed on the inner surface 52 of the pipe 50 described above is measured by the probe 4 arranged inside 51 of the pipe 50 described above. This is a film thickness measurement method for this purpose. Then, as shown in FIG. 2, this film thickness measurement method includes an ultrasonic wave transmission step S3, a first bottom surface echo reception step S4, a second bottom surface echo reception step S5, and a film thickness calculation step S6. ..

As shown in FIGS. 3A, 4A and 5A, in the ultrasonic wave transmission step S3, the probe 4 transmits ultrasonic waves U from the inside 51 of the pipe 50 toward the inner surface 52 of the pipe 50, and the surface of the scale 54. 55, the reflected wave reflected by the inner surface 52 of the pipe 50 or the outer surface 53 of the pipe 50 is received. The reflected wave includes a surface echo S, a boundary surface echo I, and a bottom surface echo B. The surface echo S is shown in FIG. 3A (a), the boundary surface echo I is shown in FIG. 3A (b), and the bottom surface echo B is shown in FIGS. 4A and 5A.
The probe 4 can simultaneously receive the surface echo S, the boundary surface echo I, and the bottom surface echo B.

In the surface echo S, as shown in FIG. 3A (a), the ultrasonic wave U transmitted from the probe 4 toward the inner surface 52 of the pipe 50 is not incident on the scale 54, and the surface 55 of the scale 54 is not incident. It is a reflected wave reflected by.

In the boundary surface echo I, as shown in FIG. 3A (b), the ultrasonic wave U transmitted from the probe 4 toward the inner surface 52 of the pipe 50 is not incident on the thick portion of the pipe 50, and the pipe is connected. It is a reflected wave reflected by the inner surface 52 of 50 (the interface between the scale 54 and the pipe 50).

In the bottom echo B, as shown in FIGS. 4A and 5A, the ultrasonic wave U transmitted from the probe 4 toward the inner surface 52 of the pipe 50 is incident on the inner surface 52 of the pipe 50, and is incident on the inner surface 52 of the pipe 50 by the outer surface 53 of the pipe 50. It is a reflected reflected wave. Of the bottom echo B, the primary reflection bottom echo that reflects once with the outer surface 53 of the pipe 50 is shown in FIG. 4A, and the secondary reflection bottom echo that reflects twice with the outer surface 53 of the pipe 50 is shown in FIG. 5A. ing.

In FIG. 4A (a), the first is received by the probe 4 without being reflected even once on the inner surface 52 of the pipe 50 or the surface 55 of the scale 54 after being reflected with the outer surface 53 of the pipe 50. The primary reflection bottom echo B01 (B) is shown. In FIG. 4A (b), a second second surface is reflected by the outer surface 53 of the pipe 50, then reflected by the surface 55 of the scale 54, reflected by the inner surface 52 of the pipe 50, and then received by the probe 4. The primary reflection bottom echo B02 (B) is shown. In FIG. 4A (c), the third is reflected by the inner surface 52 of the pipe 50, then reflected by the surface 55 of the scale 54, reflected by the outer surface 53 of the pipe 50, and then received by the probe 4. The primary reflection bottom echo B03 (B) is shown.

In FIG. 5A (a), the first reflection is reflected on the outer surface 53 of the pipe 50, is reflected on the surface 55 of the scale 54, is reflected again on the outer surface 53 of the pipe 50, and is received by the probe 4. Secondary reflection bottom echo B11 (B) is shown. In FIG. 5A (b), after reflecting off the outer surface 53 of the pipe 50, it is reflected on the inner surface 52 of the pipe 50, reflected again on the outer surface 53 of the pipe 50, and then received by the probe 4. Secondary reflection bottom echo B12 (B) is shown. In FIG. 5A (c), after reflecting off the outer surface 53 of the pipe 50, the reflection is reflected on the surface 55 of the scale 54, is reflected again on the outer surface 53 of the pipe 50, is reflected again on the surface 55 of the scale 54, and is reflected on the surface 55 of the scale 54. A third secondary reflection bottom echo B13 (B) is shown, which is reflected by the inner surface 52 of the surface and then received by the probe 4. In FIG. 5A (d), after reflecting off the inner surface 52 of the pipe 50, the surface 55 of the scale 54 reflects, the outer surface 53 of the pipe 50 reflects, the surface 55 of the scale 54 reflects again, and the pipe 50 again. A fourth secondary reflection bottom echo B14 (B) is shown, which is reflected by the outer surface 53 of the surface and then received by the probe 4.

As shown in FIG. 5A (a), in the first bottom surface echo receiving step S4, the ultrasonic wave U incident on the surface 55 of the scale 54 is the first bottom surface echo B11 reflected by the outer surface 53 of the pipe 50. The probe 4 receives the first bottom surface echo B11 propagating the first propagation path A11 that repeatedly reciprocates from the outer surface 53 of the pipe 50 to the surface 55 of the scale 54 n times (where n is a natural number of 1 or more). .. In the embodiment shown in FIG. 5A (a), the case of n = 1 is shown, and the first secondary reflection bottom echo B11 propagating in the first propagation path A11 corresponds to the first bottom echo B11. ing.

As shown in FIG. 5A (b), in the second bottom surface echo receiving step S5, the ultrasonic wave U incident on the surface 55 of the scale 54 is the second bottom surface echo B12 reflected by the outer surface 53 of the pipe 50. 2. Is received by the probe 4. In the embodiment shown in FIG. 5A (b), the case of n = 1 is shown, and the second secondary reflection bottom echo B12 propagating in the second propagation path A12 corresponds to the second bottom echo B12. ing.

As shown in FIG. 5B, in the film thickness calculation step S6, the search is performed in the first propagation time T11 and the second bottom echo reception step S5 in which the first bottom echo B11 is received by the probe 4 in the first bottom echo reception step S4. The film thickness h1 of the scale 54 is calculated based on the difference ΔT from the second propagation time T12 that received the second bottom surface echo B12 by the tentacle 4.

In the embodiment shown in FIG. 5B, in the film thickness calculation step S6, the first bottom surface echo B11 detected by the probe 4 receiving the first bottom surface echo B11 has the maximum peak. Scale based on the difference ΔT between the propagation time T11 and the second propagation time T12 at which the detection waveform of the second bottom surface echo B12 detected by the probe 4 receiving the second bottom surface echo B12 has the maximum peak. The film thickness h1 of 54 is calculated. For example, the film thickness h1 of the scale 54 is calculated by multiplying this difference ΔT by the speed at which the first bottom surface echo B11 passes through the scale 54.

According to the film thickness measuring method according to the embodiment of the present invention, the film thickness h1 of the scale 54 formed on the inner surface 52 of the pipe 50 by the probe 4 arranged inside the pipe 50. To measure. Therefore, it is not necessary to perform a pretreatment such as removing the outer surface scale formed on the outer surface 53 of the pipe 50, and the film thickness of the scale 54 can be continuously measured. Further, even in a place such as an attached metal fitting or an intersection where it is difficult to hit the probe 4 on the outer surface 53 of the pipe 50, the probe 4 is arranged inside the pipe 50, so that the scale is reached. The film thickness h1 of 54 can be easily measured.

Further, according to the film thickness measuring method according to the embodiment of the present invention, in the first bottom surface echo receiving step S4, the first bottom surface echo B11 propagating in the first propagation path A11 is received, and the second bottom surface echo is received. In the reception step S5, the second bottom surface echo B12 propagating along the second propagation path A12 is received. The first propagation path A11 is a path that repeatedly reciprocates from the outer surface 53 of the pipe 50 to the surface 55 of the scale 54 one (n = 1) times, and the second propagation path A12 is a pipe from the outer surface 53 of the pipe 50. This is a path that reciprocates to the inner surface 52 of the 50 at least once and reflects the second bottom surface echo B12 1 (n = 1) times on the outer surface 53 of the pipe 50.

Therefore, the first propagation path A11 is longer than the second propagation path A12 so as to correspond to the length from the inner surface 52 of the pipe 50 to the surface 55 of the scale 54 (the film thickness h1 of the scale 54). Therefore, the film thickness h1 of the scale 54 is set based on the difference ΔT between the first propagation time T11 when the probe 4 receives the first bottom surface echo B11 and the second propagation time T12 when the probe 4 receives the second bottom surface echo B12. Can be calculated. For example, in the embodiment shown in FIG. 5A, the first propagation path A11 is longer than the second propagation path A12 by a size twice the film thickness h1 of the scale 54. Therefore, the film thickness h1 of the scale 54 can be calculated based on the difference ΔT.

Further, as shown in FIG. 5B, each of the first bottom surface echo B11 and the second bottom surface echo B12 has a maximum peak immediately after the start of reception, and the peak gradually decreases toward the completion of reception. Further, the maximum peak of the first bottom surface echo B11 is larger than the maximum peak of the second bottom surface echo B12. Then, according to the film thickness measurement method according to the embodiment of the present invention, since the first propagation path A11 is longer than the second propagation path A12, the first bottom surface echo B11 is received after the second bottom surface echo B12. Is started.

Therefore, even if the probe 4 starts receiving the first bottom surface echo B11 while receiving the second bottom surface echo B12, for example, the first bottom surface echo B11 and the third bottom surface echo B11 as shown in FIG. 5B. Compared with the case of separating the secondary reflection bottom surface echo B13, it becomes easier to separate the first bottom surface echo B11 and the second bottom surface echo B12. Therefore, even if the scale 54 having a thin film thickness is formed on the inner surface 52 of the pipe 50, the film thickness h1 of the scale 54 is calculated by the first bottom surface echo B11 and the second bottom surface echo B12 that can be easily separated. be able to.

As shown in FIG. 3B, the probe 4 receives the boundary surface echo I after the surface echo S. The peak of the surface echo S is larger than the peak of the boundary surface echo I. Further, the difference between the time for receiving the surface echo S and the time for receiving the boundary surface echo I is smaller than the difference ΔT between the first propagation time T11 and the second propagation time T12 described above. Therefore, it is not easy to separate the surface echo S and the boundary surface echo I, and it is difficult to calculate the film thickness h1 of the scale 54 from the surface echo S and the boundary surface echo I.
Similarly, as shown in FIG. 4B, it is not easy to separate the first primary reflection bottom echo B01 and the second primary reflection bottom echo B02, and the first primary reflection bottom echo B01 and the second primary reflection B01 are not easy to separate. It is difficult to calculate the film thickness h1 of the scale 54 by the reflection bottom echo B02.

In some embodiments, as shown in FIG. 2, the film thickness measuring method further comprises a water immersion step S1 prior to the ultrasonic transmission step S3. Then, in this water immersion step S1, the inside 51 of the pipe 50 is filled with water.

When ultrasonic waves U are transmitted / received after the probe 4 and the test body (for example, the pipe 50) are filled with water, the scale 54 formed on the surface of the test body (inner surface 52 of the pipe 50) It is known that the roughness of the surface 55) has a small effect on the detection accuracy of the echo.

According to such a method, the space between the probe 4 and the pipe 50 is filled with water. Therefore, the film thickness h1 of the scale 54 can be easily measured as compared with the case where the probe 4 and the pipe 50 are not filled with water.

FIG. 6 is an explanatory diagram for explaining a radial movement step of the film thickness measuring method according to the embodiment of the present invention.

In some embodiments, as shown in FIG. 2, the film thickness measuring method further comprises a radial movement step S2. Then, in the radial movement step S2, as shown in FIG. 6, the probe 4 is moved along the radial direction of the main body 6.

In the embodiment shown in FIG. 6, the probe 4 is supported by the main body 6 via a support 8 described later. Then, as the support portion 8 moves along the radial direction, the probe 4 moves in the radial direction with respect to the main body portion 6. Further, the radial direction of the main body 6 and the direction in which the probe 4 transmits the ultrasonic wave U toward the inner surface 52 of the pipe 50 are substantially the same direction.

According to such a method, the probe 4 transmits and receives ultrasonic waves U to the inner surface 52 of the pipe 50 by changing the radial length from the probe 4 to the inner surface 52 of the pipe 50. can do. Therefore, the length of the first bottom surface echo B11 and the second bottom surface echo B12 received by the probe 4 in the radial direction (the length of the water distance d) from the probe 4 to the inner surface 52 of the pipe 50. The film thickness h1 of the scale 54 formed on the inner surface 52 of the pipe 50 can be measured by adjusting so that the separability is optimized.

In some embodiments, as shown in FIG. 2, the film thickness measuring method further comprises a wall thickness calculation step S7. Then, in the wall thickness calculation step S7, the wall thickness h2 of the pipe 50 is calculated based on the film thickness h1 of the scale 54 calculated in the film thickness calculation step S6.

The distance H from the outer surface 53 of the pipe 50 to the surface 55 of the scale 54 is calculated based on, for example, the time difference between receiving the surface echo S described above and the first primary reflection bottom echo B01. Further, as described above, in the film thickness calculation step S6, the size of the film thickness h1 of the scale 54 is calculated. Then, in the wall thickness calculation step S7, the wall thickness h2 of the pipe 50 is calculated by subtracting the film thickness h1 of the scale 54 from the calculated distance H.

According to such a method, the film thickness h1 of the scale 54 formed on the inner surface 52 of the pipe 50 and the wall thickness h2 of the pipe 50 can be calculated at the same time.

In some embodiments, as shown in FIG. 2, the film thickness measuring method further includes a film thickness calculation step S6 followed by a determination step S8 to determine whether to end the measurement of the film thickness h1 on the scale 54. Be prepared. In the embodiment shown in FIG. 2, the determination step S8 is executed after the wall thickness calculation step S7. Whether or not the measurement of the film thickness h1 of the scale 54 is finished is determined by, for example, whether or not the worker can separate the first bottom surface echo B11 and the second bottom surface echo B12 via a monitor (not shown). It is done by. When the first bottom surface echo B11 and the second bottom surface echo B12 are separable, it is determined that the measurement of the film thickness h1 of the scale 54 is finished (determination step S8: Yes), and the measurement of the film thickness h1 of the scale 54 is finished. do. On the other hand, when the first bottom surface echo B11 and the second bottom surface echo B12 are not separable, the measurement of the film thickness h1 of the scale 54 is continued (determination step S8: No), and the process returns to the radial movement step S2. Then, in the radial movement step S2, the first bottom surface echo B11 and the second bottom surface echo B12 are adjusted to a water distance d different from the water distance d that could not be separated, and the first bottom surface echo is received again. Step S4 and second bottom echo reception step S5 are executed.

According to such a configuration, when the film thickness h1 of the scale 54 or the wall thickness h2 of the pipe 50 cannot be calculated due to the failure to acquire an appropriate detection waveform, the radial movement step S2 In, the water distance d can be changed, and the first bottom surface echo receiving step S4 and the second bottom surface echo receiving step S5 can be executed again. Therefore, since the first bottom surface echo receiving step S4 and the second bottom surface echo receiving step S5 are executed at a more appropriate water distance d, the film thickness h1 of the scale 54 or the wall thickness h2 of the pipe 50 is appropriately adjusted. Can be measured.

Although the case where n = 1 has been described with reference to FIGS. 5A and 5B, the film thickness h1 of the scale 54 is measured by the film thickness measuring method as described above even if n is a natural number of 2 or more. be able to. However, as n increases, the peak of the detection waveform detected by the probe 4 becomes smaller, and it becomes difficult to separate the first bottom surface echo B11 and the second bottom surface echo B12. Therefore, it is desirable to measure the film thickness h1 of the scale 54 by the first bottom surface echo B11 and the second bottom surface echo B12.

FIG. 7 is a block diagram showing an internal configuration of a controller according to an embodiment of the present invention.

The film thickness measuring device 1 according to the embodiment of the present invention is a device for measuring the film thickness h1 of the scale 54 formed on the inner surface 52 of the pipe 50 from the inside 51 of the pipe 50. Then, as shown in FIG. 1, the film thickness measuring device 1 includes a film thickness sensor 2 and a controller 3.

As shown in FIG. 1, the film thickness sensor 2 is configured to be capable of transmitting ultrasonic waves U from the inside 51 of the pipe 50 toward the inner surface 52 of the pipe 50, and has the above-mentioned first bottom surface echo B11 and second bottom surface. It has a probe 4 capable of receiving echo B12.

As shown in FIG. 7, the controller 3 has a first propagation time T11 that receives the first bottom surface echo B11 by the probe 4 and a second propagation time T12 that receives the second bottom surface echo B12 by the probe 4. It is possible to execute the film thickness calculation process for calculating the film thickness h1 of the scale 54 based on the difference ΔT.

In the embodiment shown in FIG. 1, the controller 3 is arranged outside the pipe 50, and the controller 3 and the film thickness sensor 2 are electrically connected via a cable (not shown).
As shown in FIG. 7, the controller 3 is composed of, for example, a central processing unit (CPU30) including a processor, a random access memory (RAM31), a read-only memory (ROM32), an I / O interface 33, and the like. .. Then, the controller 3 calculates the film thickness h1 of the scale 54 by executing, for example, a program (film thickness calculation process) stored in the ROM 32 by the CPU 30.

According to the film thickness measuring device 1 according to the embodiment of the present invention, the film thickness of the scale 54 formed on the inner surface 52 of the pipe 50 by the probe 4 arranged inside the pipe 50. Measure h1. Therefore, it is not necessary to perform a pretreatment such as removing the outer surface scale formed on the outer surface 53 of the pipe 50, and the film thickness h1 of the scale 54 can be continuously measured. Further, even in a place such as an attached metal fitting or an intersection where it is difficult to hit the probe 4 on the outer surface 53 of the pipe 50, the probe 4 is arranged inside the pipe 50, so that the scale is reached. The film thickness h1 of 54 can be measured.

Further, according to the film thickness measuring device 1 according to the embodiment of the present invention, the film thickness sensor 2 transmits the first bottom surface echo B11 propagating the first propagation path A11 and the second propagation path A12. It has a probe 4 configured to be able to receive the propagating second bottom surface echo B12. The first propagation path A11 is a path that repeatedly reciprocates from the outer surface 53 of the pipe 50 to the surface 55 of the scale 54 one (n = 1) times, and the second propagation path A12 is a pipe from the outer surface 53 of the pipe 50. This is a path that reciprocates to the inner surface 52 of the 50 at least once and reflects the second bottom surface echo B12 1 (n = 1) times on the outer surface 53 of the pipe 50. Therefore, the first propagation path A11 is longer than the second propagation path A12 so as to correspond to the length from the inner surface 52 of the pipe 50 to the surface 55 of the scale 54. Therefore, the controller 3 calculates the film thickness h1 of the scale 54 based on the difference ΔT between the first propagation time T11 that received the first bottom surface echo B11 and the second propagation time T12 that received the second bottom surface echo B12. can do.

Further, according to such a configuration, since the first propagation path A11 is longer than the second propagation path A12, the reception of the first bottom surface echo B11 is started after the second bottom surface echo B12. Therefore, even if the probe 4 starts receiving the first bottom surface echo B11 while the probe 4 is receiving the second bottom surface echo B12, the first bottom surface echo B11 and the second bottom surface echo B12 are separated. Becomes easier. Therefore, even if the scale 54 having a thin film thickness is formed on the inner surface 52 of the pipe 50, the controller 3 has the film thickness of the scale 54 by the first bottom surface echo B11 and the second bottom surface echo B12 which can be easily separated. h1 can be calculated.

In some embodiments, as shown in FIG. 1, the film thickness sensor 2 further comprises a body 6 that supports the probe 4, and the film thickness sensor 2 is along the circumferential direction of the body 6. A first-row probe group 12 composed of a plurality of probes 4 arranged, and a second-row probe group 14 composed of a plurality of probes 4 arranged along the circumferential direction of the main body 6. including. The second probe group 14 is adjacent to the first row probe group 14. The probe 4 of the first row probe group 12 and the probe 4 of the second row probe group 14 are arranged so as to be displaced from each other in the circumferential direction.

In the embodiment shown in FIG. 1, the first row probe group 12 is located on the tip side in the axial direction from the second row probe group 14. Then, in the circumferential direction, the first-row probe group 12 and the second-row probe group 14 are the center positions of the plurality of probes 4 included in the first-row probe group 12 and the second-row probe. The center positions of the plurality of probes 4 included in the tentacle group 14 are arranged so as to be offset from each other.
As shown in FIG. 1, the film thickness sensor 2 may further include a third row probe group 16 composed of a plurality of probes 4 arranged along the circumferential direction of the main body 6. Then, the third row probe group 16 is adjacent to the second row probe group 14 so as to be on the opposite side of the second row probe group 14 with the first row probe group 12 in between. is doing. Then, the probe 4 of the first row probe group 12, the probe 4 of the second row probe group 14, and the probe 4 of the third row probe group 14 surround each other. They are arranged so that they are offset in the direction.

According to such a configuration, the probe 4 of the first row probe group 12 and the probe 4 of the second row probe group 14 are displaced from each other in the circumferential direction (for example, staggered). (Like) are arranged. Therefore, by moving the main body 6 in the axial direction, the probe 4 of the first row probe group 12 cannot transmit / receive ultrasonic waves U with respect to the range of the inner surface 52 of the pipe 50. , The ultrasonic wave U can be transmitted and received by the probe 4 of the second row probe group 14. Therefore, the film thickness measuring device 1 can measure the film thickness h1 of the scale 54 over the entire circumference of the inner surface 52 of the pipe 50.

As shown in FIG. 6, in some embodiments, as described above, the film thickness sensor 2 further includes a body portion 6 that supports the probe 4. The position of the probe 4 in the radial direction of the main body 6 is variably configured.

In the embodiment shown in FIG. 6, the main body 6 is formed with a recess 9 on the outer peripheral surface 6a of the main body 6. The film thickness sensor 2 further includes a support portion 8 that moves in the radial direction inside the recess 9. A probe 4 is attached to the radial outer tip of the support portion 8, whereby the probe 4 is supported by the main body portion 6 via the support portion 8 and the main body portion. The position of 6 in the radial direction is variably configured.

According to such a configuration, the probe 4 changes the radial length (water distance d) from the probe 4 to the inner surface 52 of the pipe 50, and ultrasonic waves are applied to the inner surface 52 of the pipe 50. U can be sent and received. Therefore, the film thickness measuring device 1 can measure the film thickness h1 of the scale 54 by optimizing the radial length (water distance d) from the probe 4 to the inner surface 52 of the pipe 50.

In some embodiments, as shown in FIG. 1, the film thickness measuring device 1 can be inserted into the inner 51 of the pipe 50, and the rod-shaped member 20 to which the film thickness sensor 2 is attached and the shaft of the rod-shaped member 20 are attached. Further, a centering jig 22 attached to the rod-shaped member 20 at a position different from that of the film thickness sensor 2 in the direction is provided. In the embodiment shown in FIG. 1, the film thickness measuring device 1 is attached to the tip of the rod-shaped member 20, and further includes a tip guide 26 for guiding the film thickness sensor 2 to be inserted into the inside 51 of the pipe 50. ..

In the embodiment shown in FIG. 1, the centering jig 22 is attached with a brush 24 extending radially toward the inner surface 52 of the pipe 50. The centering jig 22 is attached to the tip of the main body 6, the rear end of the main body 6, and the rear end of the tip guide 26 in the axial direction.

According to such a configuration, the inclination of the film thickness sensor 2 with respect to the inner surface 52 of the pipe 50 is adjusted by the centering jig 22 attached to the rod-shaped member 20. For example, the inclination of the film thickness sensor 2 is adjusted so that the ultrasonic wave U is vertically incident on the inner surface 52 of the pipe 50. Therefore, the signal levels of the first bottom surface echo B11 and the second bottom surface echo B12 received by the probe 4 can be improved.

Although the film thickness measuring method and the film thickness measuring device according to the embodiment of the present invention have been described above, the present invention is not limited to the above-described embodiment, and various types within a range not deviating from the object of the present invention. Can be changed.

1 Thickness measuring device 2 Thickness sensor 3 Controller 4 Detector 6 Main body 8 Support 9 Recess 12 First row probe group 14 Second row probe group 16 Third row probe group 20 Rod-shaped member 22 Alignment jig 24 Brush 26 Tip guide 30 CPU
31 RAM
32 ROM
33 I / O interface 50 Piping 51 Inside 52 Inner surface 53 Outer surface 54 Scale 55 Surface A11 First propagation path A12 Second propagation path B Bottom echo B01 First primary reflection Bottom echo B02 Second primary reflection Bottom echo B03 Third Primary reflection bottom echo B11 First secondary reflection bottom echo (first bottom echo)
B12 Second secondary reflection bottom echo (second bottom echo)
B13 Third secondary reflection bottom echo B14 Fourth secondary reflection bottom echo I Boundary surface echo S Surface echo S1 Water immersion step S2 Radial movement step S3 Ultrasonic transmission step S4 First bottom echo reception step S5 Second bottom Echo reception step S6 Thickness calculation step S7 Wall thickness calculation step S8 Determination step T11 First propagation time T12 Second propagation time U Ultrasonic d Water distance h1 Scale thickness h2 Pipe wall thickness

Claims (2)

This is a film thickness measuring method for measuring the film thickness of a scale formed on the inner surface of a pipe by a probe arranged inside the pipe.
A water immersion step of filling the inside of the pipe with water,
It is a radial movement step of moving the probe along the radial direction of the main body supporting the probe, and is a distance between the inner surface of the pipe and the probe along the radial direction. A radial movement step that moves the probe so that the water distance is the first distance,
After the water immersion step, an ultrasonic transmission step of transmitting ultrasonic waves from the inside of the pipe toward the inner surface of the pipe by the probe moved in the radial movement step.
The ultrasonic wave incident on the surface of the scale is a first bottom surface echo reflected on the outer surface of the pipe, and n times (where n is 1 or more) from the outer surface of the pipe to the surface of the scale. (Natural number) The first bottom surface echo receiving step of receiving the first bottom surface echo propagating in the first propagation path that repeatedly reciprocates by the probe, and the first bottom surface echo receiving step.
The ultrasonic waves incident on the surface of the scale are second bottom surface echoes reflected by the outer surface of the pipe, and reciprocate at least once from the outer surface of the pipe to the inner surface of the pipe. A second bottom surface echo receiving step of receiving the second bottom surface echo propagating through the second propagation path that reflects the second bottom surface echo on the outer surface of the pipe n times by the probe, and
The first propagation time when the first bottom surface echo was received by the probe in the first bottom surface echo receiving step and the second propagation time when the second bottom surface echo was received by the probe in the second bottom surface echo receiving step. A film thickness calculation step for calculating the film thickness of the scale based on the difference from time, and
After the film thickness calculation step, a determination step for determining whether to end the measurement of the film thickness of the scale, and
When it is determined in the determination step that the measurement of the film thickness is not completed, the radial re-movement step of moving the probe so that the water distance becomes a second distance different from the first distance, and
A film thickness measurement method comprising. The film thickness measuring method according to claim 1, further comprising a wall thickness calculation step of calculating the wall thickness of the pipe based on the film thickness of the scale calculated by the film thickness calculation step.

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