JP6496181B2 - Ultrasonic measurement method and ultrasonic measurement apparatus - Google Patents

Description

  The present disclosure relates to an ultrasonic measurement method and an ultrasonic measurement apparatus that measure the amount of an adhering layer attached to one surface of an object to be inspected having two opposing surfaces using ultrasonic waves.

  For example, in structures such as the main steam pipe and superheater pipe of a boiler, a fluid component flowing in a pipe such as a steam oxidation scale generated by steam oxidation of the pipe inner surface over time or a furnace wall pipe constituting a combustion chamber An adherent layer is formed by the scale containing the material adhering to and depositing on the tube wall. As described above, the scale generated by oxidizing the inner surface of the tube and the scale attached to the inner surface of the tube are adhered and deposited in the tube. These scales may hinder tube heat transfer, cause abnormal temperature gradients in the tube, increase pressure loss, etc., and cause tube blasting, creep damage, peeling, and causing other equipment to malfunction. There is. Therefore, it is necessary to clean and replace the inner surface of the tube at an appropriate time, and it is necessary to measure the scale of the inner surface of the tube in order to know the appropriate time.

  As an inspection method of this kind of deposit layer, for example, Patent Document 1 discloses an inspection for determining the adhesion state of a scale based on a resistance change between electrodes installed in a pipe.

Japanese Patent Laid-Open No. 10-23559

  However, in the above-mentioned patent document 1, since it is necessary to attach a pipe to which an inspection electrode is attached to an actual machine line, there is a problem that troublesome work takes time and installation costs are required. Further, if the electrode is removed from the pipe during plant operation, the electrode may cause a problem.

  Therefore, non-destructive inspection using ultrasonic waves is known to solve such problems. In the inspection using ultrasonic waves, an ultrasonic probe is arranged on one surface of the object to be inspected, and ultrasonic waves are transmitted toward the other surface on which the adhered layer is formed, and the other surface (inspected object). And the reflection echo reflected at the end of the deposit layer (the boundary surface where the deposit layer and the fluid in the tube contact) are received. Then, the deposit layer is evaluated by converting the reception time difference between the reflection echo on the other surface and the reflection echo at the end of the deposit layer into a distance.

  However, in the conventional ultrasonic inspection technique, it was necessary to change the measurement conditions in accordance with the component, density, and the like of the deposit layer in order to perform an accurate inspection. For this reason, if the state of the deposit layer is not known in advance, the inspection must be performed while trial and error in the measurement conditions by trial and error, so that the burden of time and cost tends to increase. In particular, since the scale adhering to the inner surface of the pipe is often difficult to confirm directly from the outside, such a problem is likely to occur.

  At least one embodiment of the present invention has been made in view of the above-described problems, and provides an ultrasonic measurement method and an ultrasonic measurement apparatus capable of easily and accurately evaluating an adhering layer using an ultrasonic probe. The purpose is to do.

(1) In order to solve the above problems, an ultrasonic measurement method according to at least one embodiment of the present invention transmits a transmission probe among ultrasonic probes on one surface of an object to be inspected having two surfaces facing each other. A receiving probe is arranged in the ultrasonic probe at a position different from the transmitting probe on the one surface, and is made incident on the object to be inspected from the transmitting probe. An ultrasonic measurement method for receiving an ultrasonic wave with the receiving probe and measuring an amount of an adhering layer adhering to the other surface of the object to be inspected, comprising: An ultrasonic detection step of receiving a Lamb wave generated by incidence of ultrasonic waves on an inspection object by the reception probe, and an A-mode attenuation rate among the Lamb waves received in the ultrasonic detection step Attenuation rate calculating step for calculating the A mode attenuation rate and the deposit layer Based on the relationship between, and a determination step of determining the amount of the deposit layer corresponding to the attenuation factor of the A mode that has been calculated by the attenuation rate calculating step.

  According to the configuration of (1) above, the attenuation rate is calculated based on the A mode component of the Lamb wave propagating through the object to be inspected, and the amount of the deposit layer is obtained from the attenuation rate. According to the earnest study of the present inventor, it has been found that there is a close correlation between the attenuation rate and the amount of the deposit layer based on the A mode component. By obtaining the amount of the adherent layer based on the correlation between the amplitude of the A mode and the amount of the adherent, the measurement condition can be easily and accurately attached without changing the measurement conditions for each component or density of the adherent layer. Evaluation of kimono becomes possible. In particular, even when the deposit layer is unevenly distributed on the other surface, a reliable deposit layer amount can be obtained by the above configuration.

(2) In some embodiments, in the configuration of the above (1), a probe installation in which the transmission probe and the reception probe are installed on the one surface at a predetermined distance apart from each other. The method further includes a step.

  According to the configuration of (2) above, by installing the transmission probe and the reception probe at a predetermined distance, it becomes easy to extract the A mode and S mode components from the Lamb wave, and the attenuation is accurate. The rate can be calculated. A Lamb wave includes an S mode and an A mode. Generally, the A mode has a property that the propagation speed is higher than that of the S mode. Therefore, by providing a predetermined distance between the transmission probe and the reception probe, when the Lamb wave propagated from the transmission probe reaches the reception probe, the S mode component and the A mode component are timed. Therefore, the A mode can be easily extracted.

(3) In some embodiments, in the configuration of (2) above, in the probe installation step, the transmission probe is arranged so that the ultrasonic wave is incident obliquely on the one surface of the tube. Set up a child.

  According to the configuration of (3) above, the transmission probe is installed so that the ultrasonic wave is incident obliquely with respect to one surface, so that the Lamb wave used for calculating the attenuation factor is generated in the inspected object. Therefore, more accurate measurement can be performed.

(4) In some embodiments, in any one of the above configurations (1) to (3), in the ultrasonic detection step, the amplitude change of the waveform of the Lamb wave received by the reception probe with respect to the time axis In the attenuation rate calculating step, the A-mode attenuation rate is calculated based on the amplitude in a time range earlier than the minimum value of the line connecting the peak values of the amplitudes included in the waveform of the Lamb wave. .

  According to the configuration of (4) above, in view of the property that the A-mode component of the Lamb wave has a higher propagation speed than the S-mode component, of the Lamb wave acquired as a waveform indicating a temporal amplitude change A component that is early in time (that is, a range that is earlier in time than the local minimum value of the line connecting the peak values of the amplitudes included in the waveform) is extracted as the A mode to calculate the attenuation rate.

(5) In some embodiments, in any one of the configurations (1) to (3), in the ultrasonic detection step, the waveform of the Lamb wave received by the reception probe is changed in amplitude with respect to a time axis. In the attenuation rate calculation step, the attenuation rate of the A mode is based on the time integral of the amplitude in a range earlier in time than the minimum value of the line connecting the peak values of the amplitudes included in the waveform of the Lamb wave. Is calculated.

  According to the configuration of the above (5), in view of the property that the A-mode component of the Lamb wave has a higher propagation speed than the S-mode component, of the Lamb wave acquired as a waveform indicating a temporal amplitude change , Calculating the attenuation rate by extracting the time integral of the amplitude in the early component (that is, the range earlier in time than the minimum value of the line connecting the peak values of the amplitudes included in the waveform) as the A mode. Thus, measurement with higher accuracy becomes possible.

(6) In order to solve the above-described problem, an ultrasonic measurement apparatus according to at least one embodiment of the present invention has a transmission probe among ultrasonic probes on one surface of an object to be inspected having two surfaces facing each other. A receiving probe is arranged in the ultrasonic probe at a position different from the transmitting probe on the one surface, and is made incident on the object to be inspected from the transmitting probe. An ultrasonic measurement apparatus that receives ultrasonic waves with the receiving probe and measures the amount of an adhering layer adhering to the other surface of the object to be inspected, the ultrasonic measuring apparatus comprising: An ultrasonic detector that receives a Lamb wave generated by incidence of ultrasonic waves on an inspection object by the reception probe, and an A-mode attenuation rate among the Lamb waves received by the ultrasonic detector An attenuation rate calculating unit for calculating the A mode attenuation rate and the amount of the deposit layer Based on the engagement, and a determination unit to determine the amount of the deposit layer corresponding to the attenuation factor of the A mode that has been calculated by the attenuation rate calculating unit.

  According to the configuration of (6) above, the above-described ultrasonic measurement method (including the above various forms) can be suitably implemented.

  According to at least one embodiment of the present invention, it is possible to provide an ultrasonic measurement method and an ultrasonic measurement apparatus capable of easily and accurately measuring the amount of the deposit layer using an ultrasonic probe.

It is a schematic diagram which shows the cross-sectional structure of the pipe | tube which is an example of a to-be-inspected object. It is a mimetic diagram showing composition of an ultrasonic measuring device for carrying out an ultrasonic measuring method concerning at least one embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. It is a schematic diagram which shows the transmission probe vicinity of FIG. 2 from the A surface side. It is one structural example of the ultrasonic measurement apparatus of FIG. FIG. 6 is an exploded view showing each member in FIG. FIG. 7 shows another configuration example of the ultrasonic measurement apparatus of FIG. FIG. 8 is an exploded view showing each member in FIG. 7. It is a block diagram which shows the internal structure of the analyzer of FIG. It is a flowchart which shows the ultrasonic measuring method which concerns on at least 1 embodiment of this invention for every process. It is a flowchart which shows the subroutine of step S10 of FIG. It is a schematic diagram which shows the mode of the S mode and A mode in the Lamb wave according to the distance between a transmission probe and a reception probe. It is a schematic diagram which shows each propagation mode in S mode and A mode of a Lamb wave. It is sectional drawing by each numerical analysis in S mode and A mode of a Lamb wave. It is a figure which shows the Lamb waveform of each ultrasonic wave in the pipe | tube with which the scale has not adhered, and the pipe | tube with which the scale has adhered. It is an example of an attenuation rate-adhesion amount map.

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 in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
In addition, for example, expressions representing shapes such as quadrangular shapes and cylindrical shapes not only represent shapes such as quadrangular shapes and cylindrical shapes in a strict geometric sense, but also within the range where the same effect can be obtained. A shape including a chamfered portion or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

First, an inspected object to be measured by the ultrasonic measurement method according to at least one embodiment of the present invention and an ultrasonic measurement apparatus for performing the ultrasonic measurement method will be described. FIG. 1 is a schematic diagram showing a cross-sectional structure of a tube 1 which is an example of an object to be inspected, and FIG. 2 shows a configuration of an ultrasonic measurement apparatus for performing an ultrasonic measurement method according to at least one embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 4 is a schematic view showing the vicinity of the transmission probe 12a in FIG.

  The tube 1 has one surface (A surface) and the other surface (B surface). First, an inner layer formed by oxidizing the inner surface of the tube 1 by high-temperature oxidation or the like on the B surface shown in FIG. A scale or a scale 2 including an outer scale formed by adhering a component of a fluid flowing inside the pipe is attached and deposited. In FIG. 1, as an example, a porous scale 2 having a large number of voids 3 inside the scale 2 (hereinafter referred to as a porous scale) is shown.

  As shown in FIGS. 2 and 3, the ultrasonic measurement apparatus 10 includes an ultrasonic flaw detector 12 capable of transmitting and receiving ultrasonic waves, and the ultrasonic flaw detector 12 is located at different positions on the A surface of the tube 1. The transmission probe 12a and the reception probe 12b are arranged. In the ultrasonic probe 12 arranged in this way, ultrasonic waves are incident on the tube 1 from the transmission probe 12a, and the propagation wave is received by the reception probe 12b. Then, the incident state at the transmission probe 12a and the reception state at the reception probe 12b are sent to the analysis apparatus 100 as electrical signals. In the analysis device 100, calculation is performed based on the received signal, and the amount of the deposit layer adhering to the B surface of the tube 1 is evaluated.

  The ultrasonic measurement apparatus 10 includes a first support member 16a, a second support member 16b, and a guide member 18. The first support member 16a holds the transmission probe 12a in the direction perpendicular to the A plane so that transmission of ultrasonic waves from the lower surface (the surface facing the A surface) of the transmission probe 12a to the tube 1 is not hindered. It is configured to support at least from the side. The second support member 16b holds the reception probe 12b on the A surface so that the ultrasonic wave propagating through the tube 1 is not obstructed when it is received by the lower surface (the surface facing the A surface) of the reception probe 12b. It is comprised so that it may support from at least a side with respect to the perpendicular | vertical direction. Thus, the transmission probe 12A and the reception probe 12b are stably supported by the first support member 16a and the second support member 16b, respectively.

  The first support member 16a and the second support member 16b that respectively support the transmission probe 12A and the reception probe 12b are provided on a guide member 18 that is installed so as to extend along the axial direction of the tube 1. Each is fixed. The guide member 18 is disposed so as to contact the side surfaces of the first support member 16a and the second support member 16b (that is, at least in the direction crossing the A surface of the tube 1), and the first support member 16a and A plurality of through holes 20 are provided along the axial direction of the tube 1 in a range corresponding to the second support member 16b.

  On the side surface of the transmission probe 12a, there is provided an engagement hole 24 configured such that the tip of a bolt 22 inserted into a through hole 20 provided in a range corresponding to the transmission probe 12a can be engaged. ing. The bolt 22 is inserted from the outside into a through hole 20 provided in the guide member 18, and its tip is engaged with the engagement hole 24, so that the transmission probe 12 a can be fixed to the guide member 18. It is configured. In this embodiment, in particular, the transmission probe 12a is provided with respect to the guide member 18 by providing two engagement holes 24 along the extending direction of the tube 1 on the side surface of the transmission probe 12a and fastening them with bolts 22 respectively. The child 12a is configured to be stably fixed. A plurality of through holes 20 are provided in the guide member 18 along the axial direction. By selecting the through holes 20 into which the bolts 22 are inserted, the fixing position of the transmission probe 12a with respect to the guide member 18 is pivoted. It is configured to be variable along the direction.

  Similarly, the receiving probe 12b is provided with an engaging hole 24 configured to be able to engage the tip of a bolt 22 inserted into a through hole 20 provided in a range corresponding to the receiving probe 12b. ing. The bolt 22 is inserted from the outside into a through hole 20 provided in the guide member 18, and its tip is engaged with the engagement hole 24, so that the receiving probe 12 b can be fixed to the guide member 18. It is configured. Particularly in this embodiment, the receiving probe 12b is provided with two engaging holes 22 along the extending direction of the tube 1 and fixed with bolts 22 respectively, whereby the receiving probe 12b is fixed to the guide member 18. Is configured to be stably fixed. A plurality of through holes 20 are provided in the guide member 18 along the axial direction. By selecting the through holes 20 into which the bolts 22 are inserted, the fixing position of the reception probe 12b with respect to the guide member 18 is set as an axis. It is configured to be variable along the direction. As a result, the distance between the first support member 16a and the second support member 16b is variable while the first support member 16a and the second support member 16b are stably fixed to the guide member 18. The structure can be realized.

  Thus, in some embodiments, the guide member 18 is formed to at least partially cover the first support member 16 a and the second support member 16 b, and the first member is fixed by a fixing means such as a bolt 22. The supporting member 16a and the second supporting member 16b can be fixed from the side. In particular, the distance between the transmission probe 12a and the reception probe 12b is variably configured by variably configuring the fixed positions of the transmission probe 12a and the reception probe 12b with respect to the guide member 18. .

  As shown in FIGS. 3 and 4, a contact sheet 26 is provided on the side facing the A surface of the transmission probe 12a and the reception probe 12b. The contact sheet 26 includes a function as a medium for facilitating transmission / reception of ultrasonic waves between the probe 12 and the tube 1, and is preferably detachable a plurality of times with respect to the A surface or soiled. It may be formed of a material that can be reused by cleaning. Further, by forming the contact sheet 26 with a material such as rubber, the contact state with the A surface is made dense, and the frictional force between the A surface and the A surface is improved, thereby effectively shifting the position during measurement. Can be prevented. Conventionally, in this type of ultrasonic measurement apparatus, a gel-like medium such as glycerin is applied between the probe and the A surface. Instead, by using the contact sheet 26 described above, Since there is no need to apply or remove the gel-like medium as in the prior art, it is possible to efficiently transmit and receive ultrasonic waves while effectively shortening the working time.

  Moreover, the surface which opposes A surface among the 1st support member 16a and the 2nd support member 16b is formed so as to correspond to the surface shape of the pipe | tube 1 which is a to-be-inspected object. Especially in this embodiment, since the cut surface in the surface perpendicular to the axial direction of the tube 1 has a cylindrical shape as shown in FIG. 3, of the first support member 16a and the second support member 16b. The surface facing the A surface also has a curved surface shape. In this way, the surface facing the A surface of the first support member 16a and the second support member 16b is formed so as to correspond to the surface shape of the tube 1, so that the transmission probe 12a and the reception on the tube 1 are formed. When the probe 12b is disposed, the transmission probe 12a and the reception probe 12b can be accurately aligned along a predetermined direction. Since the arrangement accuracy of the transmission probe 12a and the reception probe 12b has a great influence on the ultrasonic measurement result to be described later, more accurate inspection can be performed.

  In the present embodiment, the first support member 16a and the second support member 16a and the second support member 16b are formed so that the central axes of the pipe 1 and the first support member 16a and the second support member 16b are parallel to each other. The transmission probe 12a and the reception probe 12b respectively supported by 16b are configured to be stably arranged on the same straight line along the axial direction.

  Further, at least one of the first support member 16a and the second support member 16b has at least one magnet. As shown in FIG. 3 and FIG. 4, in the present embodiment, a substantially cylindrical magnet disposed along both the first support member 16 a and the second support member 16 b along the extending direction of the tube 1. 28a and 28b are provided. These magnets 28a and 28b are respectively provided on both sides of the surface facing the A surface with respect to the central axis of the tube 1, and the first support member 16a and the second support member 16a and the second support member 16 are made of the magnetic material. The support member 16b is stably adsorbed. As will be described later, in the ultrasonic measurement method according to the present embodiment, the first support member 16a and the second support member 16b are positioned on the same straight line along the axial direction, which greatly affects the measurement accuracy. However, highly accurate measurement can be ensured by the above configuration.

  When the tube 1 is formed of a material containing a magnetic body in this way, the first support member 16a and the second support member 16a and the second support member 16b have at least one magnet 28 included in the first support member 16a and the second support member 16b. The support member 16b comes into contact with the A surface stably and densely. As a result, since the distance between the transmission probe 12a and the reception probe 12b can be stably maintained with respect to the A surface in a stable state, ultrasonic measurement with higher accuracy can be performed.

  In the present embodiment, the magnets 28a and 28b have a columnar shape extending along the A direction along the axial direction, and the respective surfaces are the first support member 16a and the second support member. It is configured to be exposed to the A surface side from 16b. Thereby, each magnet will be in line contact with the A surface, and the posture can be stabilized when the first support member 16a and the second support member 16b are brought into contact with the A surface.

  The surfaces of the magnets 28a and 28b may be formed flush with the surface of the first support member 16a and the second support member 16b that faces the A surface. Thereby, it is possible to ensure good adhesion to the A surface of the transmission probe 12a and the reception probe 12b, and it is possible to perform ultrasonic measurement with higher accuracy. Moreover, when the 1st support member 16a and the 2nd support member 16b are made to contact the A surface of the pipe | tube 1 which is a measuring object, the possibility of damaging the pipe | tube 1 can be reduced effectively.

Subsequently, several embodiments of specific configuration examples of the ultrasonic measurement apparatus 10 will be described. 5 is an example of the configuration of the ultrasonic measurement apparatus 10 of FIG. 2, FIG. 6 is an exploded view showing each member in FIG. 5, and FIG. 7 is another view of the ultrasonic measurement apparatus 10 of FIG. FIG. 8 is an exploded view showing each member in FIG.
5 to 8, illustration of the transmission probe 12a supported by the first support member 16a is omitted for easy understanding of the structure of each member. 5 to 8 mainly show the structure in the vicinity of the first support member 16a, but the structure in the vicinity of the second support member 16b has the same configuration unless otherwise specified.

  First, in the configuration example shown in FIGS. 5 and 6, the first support member 16a has a substantially rectangular parallelepiped shape, and the thickness direction of the tube 1 (see FIG. 5) from the side facing the A surface of the tube 1 inside thereof. The transmission probe 1 is formed so as to surround the transmission probe 1 from the side.

  The guide member 18 is connected to the plate portion 30 that contacts the side of the first support member 16a and the upper end portion of the plate portion 30 and is bent so as to cover the first support member 16a from above. And a substantially L-shaped cross-sectional shape. When the plate portion 30 is disposed on the side of the first support member 16a, the front end of the bolt 22 inserted into the through hole 20 is provided in the fitting hole 24 provided on the side of the first support portion 16a. The first support member 16a is configured to be fixable to the plate portion 30 by being fitted to each other.

  As described above, since a plurality of through holes 20 are provided in the plate portion 30 along the extending direction of the guide member 18, by selecting the through hole 20 into which the bolt 22 is inserted, the guide 30 is guided. The position of the first support member 16a with respect to the member 18 is configured to be variable.

  In some embodiments, a buffer member 34 is further provided between the guide member 18 and at least one of the first support member 16a and the second support member 16b. In this embodiment, in particular, when the first support member 16a is fixed to the guide member 18, the space between the transmission probe 12a supported by the first support member 16a and the guide member 18 is in the space. A buffer member 34 for filling is provided. Thereby, the gap which the 1st support member 16a and the 2nd support member 16b have between the inner walls of the guide member 18 is filled up with the buffer member 34, and the play between these members can be reduced. As a result, the structural stability of the ultrasonic measurement device is improved, and more accurate measurement is possible.

  In some embodiments, the buffer member 34 is formed of a highly elastic material compared to the guide member 18 and at least one of the first support member 16a and the second support member 16b. Particularly in the present embodiment, the buffer member 34 is made of a highly elastic material compared to the guide member 18 and the first support member 16a. Thereby, the play between members can be effectively absorbed by the buffer member 34, and the said effect can be exhibited favorably.

  Specifically, the buffer member 34 is formed of a resin material that is a highly elastic material compared to the first support member 16 a and the guide member 18 formed of metal (for example, aluminum, stainless steel, or the like). Further, since the buffer member 34 is a portion that is easily worn by friction when the first support member 16a is moved along the guide member 18, the buffer member 34 is made of such a highly elastic material. It can also be effectively reduced.

  A fixing member 40 is disposed on the opposite side of the first support member 16a from the guide member 18. The fixing member 40 has a plate portion 36 that contacts the first support member 16a, and a bent portion 38 that is connected to the upper end portion of the plate portion 36 and bent so as to cover the first support member 16a from above. It has a cross-sectional shape (substantially L-shaped) similar to that of the guide member 18 described above.

  However, the guide member 18 extends along the axial direction of the tube 1 so as to include the first support member 16 a and the second support member 16 b, whereas the fixing member 40 is the first support member 16. Alternatively, the axial length is shorter than that of the guide member 18 so as to include only the second support member 16b. That is, the fixing member 40 has a function of fixing the first support member 16 or the second support member 16b to the guide member 18, respectively, and between the first support member 16 and the second support member 16b. Is adjusted by moving the corresponding fixing member 40 together with the first support member 16 and the second support member 16b with respect to the guide member 18 together.

  As described above, in some embodiments, when at least one of the first support member 16a and the second support member 16b is composed of a plurality of members, the members can be disassembled so that maintenance can be easily performed. Therefore, a configuration capable of exhibiting the various effects can be realized at low cost.

  In addition, when the first support member 16a is fixed to the fixing member 40, the gap between the transmission probe 12a supported by the first support member 16a and the fixing member 18 is the same as that of the buffer member 34 described above. In order to fill the space, a buffer member 34 having a shape corresponding to the space shape is provided. The buffer member 34 is made of a highly elastic material compared to the guide member 18 and the first support member 16a. Specifically, the buffer member 34 is formed of a resin material, and is formed with higher elasticity than the first support member 16a and the fixing member formed of metal (for example, aluminum, stainless steel, or the like).

  As shown in FIG. 6, the buffer member 34 has through holes 20 through which the bolts 22 inserted from the guide member 18 side can pass, and the tip of the inserted bolt 22 is the plate of the fixing member 40. By being fitted into the fitting hole 24 provided in the portion 36, these members can be fixed integrally. In the present embodiment, the plurality of bolts 22 are provided along the extending direction of the guide member 18, thereby improving the stability at the time of fixing.

  Subsequently, in the configuration example shown in FIGS. 7 and 8, the guide member 18 has a substantially L shape similarly to the configuration examples shown in FIGS. 5 and 6, while the fixing member 40 has a plate shape. It is different in having it. In this case, since the fixing member 40 can be completed with a simple shape, manufacturing effort and cost can be effectively suppressed.

  As described above, according to some of the above-described embodiments, the first support member 16a and the second support member 16b are supported by the guide member 18 so that the first support member 16a and the second support member 16b are supported. The transmission probe 12a and the reception probe 12b supported by the member 16a and the second support member 16b can be stably and accurately arranged on the tube 1. In particular, since the fixed positions of the first support member 16a and the second support member 16b with respect to the guide member 18 are variably configured, the transmission probes supported by the first support member 16a and the second support member 16b, respectively. The distance between the probe 12a and the reception probe 12b can be adjusted flexibly. Thus, as will be described later, when measuring the amount of the deposit layer based on the A mode included in the Lamb wave received by the receiving probe 12a, the A mode is temporally changed from the S mode having a low propagation speed. In order to detect them separately, it is necessary to adjust the distance between the transmission probe 12a and the reception probe 12b. However, such a request can be suitably met.

Next, the configuration of the analysis apparatus 100 (see FIG. 2) will be described. FIG. 9 is a block diagram showing an internal configuration of the analysis apparatus 100 of FIG.
The analysis apparatus 100 is realized by installing software relating to an ultrasonic measurement method according to at least one embodiment of the present invention in an electronic arithmetic processing apparatus such as a computer. Specifically, as shown in FIG. 9, the analysis device 100 includes an input device 110 configured to be able to input various data by an operator, and a memory configured to be able to store data and software necessary for various processes. Device 120, arithmetic device 130 configured to be able to perform arithmetic processing on information acquired from input device 110 and storage device 120, input content of input device 110, storage content of storage device 120, arithmetic result of arithmetic device 130, and the like. And an output unit 140 configured to be capable of outputting.

The input device 110 is configured to be able to input various types of information such as letters, numbers, and symbols. Specifically, the input device 110 is a human interface device that can be operated by an operator such as a keyboard, a mouse, and a touch panel. You may be comprised so that input is possible from other apparatuses, such as a medium and an arithmetic unit.
The storage device 120 is preinstalled with a program for executing the ultrasonic measurement method according to at least one embodiment of the present invention, and is configured to be appropriately executed by being read by the arithmetic device 130. The storage device 120 can use any storage device that can store a program, and may be an external medium such as a CD, a DVD, or a flash memory, and may be a RAM or a ROM.
The arithmetic device 130 executes an ultrasonic measurement method according to a program read from the storage device 120 and performs an operation using information acquired from the input device 110 and the storage device 120 in the processing. Specifically, a semiconductor device such as a microprocessor is used.
The output device 140 is a human interface device that can output various contents acquired from the input device 110 and the storage device 120, the calculation result of the calculation device 130, and the like in a format that can be recognized by the operator. The output device 140 is typically a display that appeals to the operator's vision, but may be any other device that appeals to the other five senses. Moreover, the input device 110 and the output device 140 may be integrally configured like a touch display.

In FIG. 9, the configuration of the arithmetic device 130 is particularly shown as a functional block configuration diagram. The arithmetic device 130 includes an ultrasonic detector 132 that receives ultrasonic waves from the transmission probe to the object to be inspected and receives Lamb waves generated by the ultrasonic waves by the reception probe, and the ultrasonic detector. The attenuation rate calculation unit 134 that calculates the attenuation rate of the A mode among the Lamb waves received in the sound wave detection step, and the attenuation rate calculation based on the relationship between the attenuation rate of the S mode and the amount of the deposit layer. A determination unit 136 that obtains the amount of the adhering material layer from the attenuation rate of the A mode calculated in the process.

  Next, an ultrasonic measurement method executed by the ultrasonic measurement apparatus 1 having the above configuration will be described in detail. FIG. 10 is a flowchart showing an ultrasonic measurement method according to at least one embodiment of the present invention for each process, and FIG. 11 is a flowchart showing a subroutine of step S10 in FIG.

The ultrasonic measurement method shown in FIG. 10 includes a probe installation step (step S10) in which the transmission probe 12a and the reception probe 12b are installed on a surface A at a predetermined distance, and the transmission probe. The ultrasonic wave is incident on the tube 1 from the child 12a and the Lamb wave generated by the ultrasonic wave is received by the receiving probe 12b (Step S20), and the ram received in the ultrasonic wave detecting step. the attenuation rate calculating step of calculating the attenuation rate of the a mode of the wave (step S30), based on the relationship between the amount of attenuation factor and the scale 2 of the a mode, the attenuation of a mode calculated by the attenuation rate calculating step And a determination step (S40) for obtaining the amount of scale 2 from the rate.

  First, in the probe installation step (step S10), the transmission probe 12a and the reception probe 12b are installed on the surface A so as to be positioned at a predetermined distance (see FIG. 2). As described above, the transmission probe 12a and the reception probe 12b are installed at a predetermined distance, so that the S-mode component used for calculating the attenuation rate can be effectively extracted from the Lamb wave, and an accurate inspection can be performed. Is possible.

  As shown in FIG. 11, in the subroutine of the probe installation step (step S10), the thickness of the tube 1 that is the measurement target is measured (step S11), and transmission is performed based on the measured thickness. A distance between the probe 12a and the reception probe 12b is set (step S12). The distance between the transmission probe 12a and the reception probe 12b is determined as a distance at which the S mode and the A mode, which are included in the Lamb wave and have different propagation speeds, can be sufficiently separated. Lamb waves generally include an S mode and an A mode, but the A mode has a property that the propagation speed is higher than that of the S mode. Here, when the distance between the transmission probe 12a and the reception probe 12b is sufficiently secured, the A mode with a high propagation speed is detected earlier in time than the S mode with a low propagation speed. As shown in FIG. 12 (a), measurement results that are separable from each other are obtained. On the other hand, when the distance between the transmission probe 12a and the reception probe 12b is not sufficiently secured, the S mode and the A mode are mixed as shown in FIG.

  Thus, it has been found that the distance between the transmission probe 12a and the reception probe 12b that can sufficiently separate the S mode and the A mode has a correlation with the thickness of the tube 1. Therefore, it is preferable to obtain a correlation between the distance and the thickness in advance using a sample having the same specifications as the tube 1 to be measured. In step S12, the distance between the transmission probe 12a and the reception probe 12b is determined by applying the actual measurement value measured in step S11 to the correlation acquired in advance in this way. In step S13, ultrasonic waves are actually transmitted / received in a state where the measuring device is set to the distance between the transmission probe 12a and the reception probe 12b set in step S12, and FIG. Make sure that the S and A modes are well separated as shown.

  Referring back to FIG. 10 again, in the ultrasonic detection step (step S20), the ultrasonic detection unit 132 makes an ultrasonic wave incident on the tube 1 from the transmission probe 12a, and generates a Lamb wave generated by the ultrasonic wave. Received by the receiving probe 12b. Here, the Lamb wave is a kind of elastic wave propagating through a flat plate that is sufficiently thinner than the wavelength of the incident plane wave, and is generated by propagating longitudinal ultrasonic waves in an oblique direction with respect to the flat plate. The ultrasonic wave incident on the flat plate reaches the B surface of the flat plate, and a part of the ultrasonic wave is reflected inside the flat plate while the B surface partially transmits at the boundary surface with the internal space of the tube 1. A part of the reflected ultrasonic wave is mode-converted into a transverse ultrasonic wave and propagates in the flat plate. Such mode conversion occurs in the process of repeated reflection even on the A plane of the flat plate, and a part thereof is converted into a longitudinal wave and propagated. By repeating mode conversion in the process of propagating in this way, Lamb waves are generated as a propagation behavior in which the flat plate surface undulates when the entire flat plate is viewed. In the ultrasonic detection step, in order to effectively generate such a Lamb wave, ultrasonic waves are transmitted from the transmission probe 12a arranged on the A surface which is the outer peripheral surface of the tube 1 to the thickness direction of the tube 1. The ultrasonic waves are transmitted and received so as to be incident obliquely.

  FIGS. 13A and 13B show the propagation modes in the S mode and A mode of the Lamb wave, and FIGS. 14A and 14B show the numerical values in the S mode and A mode of the Lamb wave. A sectional view by analysis is shown. In the S mode, the A surface and the B surface of the tube 1 have a propagation behavior that repeatedly expands and contracts and bends symmetrically, and propagates along the axial direction of the tube 1 while vibrating symmetrically in the thickness direction. Such an S mode has a slow propagation speed and hardly reacts to a porous scale. On the other hand, the A mode has a propagation behavior that repeats expansion and contraction and bending asymmetrically, and propagates along the axial direction of the tube 1 while vibrating antisymmetrically in the thickness direction. Such an A mode is characterized by a high propagation speed and a large attenuation due to the porous scale.

  Subsequently, in the attenuation factor calculation step (step S30), the attenuation factor calculator 134 calculates the A-mode attenuation factor among the Lamb waves received by the ultrasonic detector 132. Here, the attenuation rate refers to the ratio of amplitude reduction accompanying the propagation of ultrasonic waves, and in the same tube 1, it varies depending on the presence or absence of a scale on the inner surface of the tube.

  A specific example of calculating the attenuation rate will be described below with reference to FIG. In the attenuation rate calculation step, first, an A mode that is a calculation reference for the attenuation rate is extracted based on the Lamb wave. The extraction of the A mode is performed, for example, by specifying a range earlier in time than the minimum value of the line connecting the peak values of the amplitudes included in the waveform of the Lamb wave acquired in the waveform acquisition process. When the waveform of the Lamb wave is acquired as an amplitude change with respect to the time axis when there is a scale, as shown in FIG. 12A, the A mode having a higher propagation speed is detected earlier than the S mode. A waveform with two peaks each corresponding to the mode is obtained. Here, a range earlier in time than the minimum value 60 of the line 50 connecting the peak values of the amplitudes included in the waveform (that is, the valley between the peaks corresponding to the S mode and the A mode) is specified as the A mode waveform. To do. As described above, this is because the A-mode component of the Lamb wave has a higher propagation speed than the S-mode component.

  Here, the solid line graph in FIG. 15 is a diagram showing the ultrasonic ram waveform of the pipe with the scale attached thereto, and the broken line graph is a diagram showing the ultrasonic ram waveform of the pipe with no porous scale attached thereto. is there. As shown in FIG. 2, this waveform is transmitted and received in the longitudinal direction using a two-probe type ultrasonic probe 12 composed of a transmission probe 12a and a reception probe 12b. Is detected. As shown in FIG. 15, when the S-mode and A-mode of the Lamb wave can be separated in time by having a sufficient inter-probe distance, the amplitude of the A-mode changes greatly depending on the presence or absence of the scale (control). Thus, the amplitude of the S mode is almost unaffected by the presence or absence of the scale).

ここで、Ａｍａｘはスケールが付着していない管のＡモード波形の振幅最大値であり、Ｂｍａｘはスケールが付着している管のＡモード波形の振幅最大値である。
なお、スケールが付着していない管１のＡモード波形は、予め実験的に取得しておくことが好ましい。
Here, the A- mode attenuation rate is calculated based on the maximum amplitude in the A- mode waveform specified as described above. For example, the amplitude of the ultrasonic wave propagated through the pipe with the scale attached (the peak amplitude of the A mode waveform in the solid line graph of FIG. 15) and the amplitude of the ultrasonic wave propagated through the pipe without the scale attached (FIG. 15). The attenuation rate is calculated from the ratio to the peak amplitude of the A mode waveform in the broken line graph. In this case, the attenuation rate P is calculated by the following calculation formula (1).

Here, Amax is the maximum amplitude value of the A-mode waveform of the pipe without the scale attached, and Bmax is the maximum amplitude value of the A-mode waveform of the pipe with the scale attached.
In addition, it is preferable to acquire experimentally the A mode waveform of the pipe | tube 1 which has not adhered the scale beforehand.

  Although the calculation formula (1) shows an example in which the attenuation rate is calculated based only on the maximum amplitude value, the attenuation rate is similarly applied to at least one adjacent peak value of the amplitude in addition to the maximum amplitude value. May be calculated. In this case, more accurate evaluation can be performed by calculating the attenuation rate based on a plurality of amplitudes of the A mode waveform.

ここで、

はスケールが付着していない管１のＡモード波形の時間積分であり、

はスケールが付着している管１のＡモード波形の時間積分である。またｔ１及びｔ２は、ラム波から抽出されたＡモード波形の時間領域を規定するための時間パラメータである。ｔ１及びｔ２は、例えば波形取得工程で取得されたラム波の波形に含まれる各振幅のピーク値を結ぶラインのうち少なくともＡモードにおける最大振幅を含む時間領域を含むように選択され、好ましくは、ラム波の波形に含まれる各振幅のピーク値を結ぶラインの極小値より時間的に早い範囲を特定するように選択されてもよい。 As another method for calculating the attenuation rate of the A mode, the attenuation rate P may be calculated by the following calculation (2) based on the integral value of the A mode waveform.

here,

Is the time integral of the A-mode waveform of tube 1 with no scale attached,

Is the time integration of the A-mode waveform of the tube 1 to which the scale is attached. T1 and t2 are time parameters for defining the time domain of the A mode waveform extracted from the Lamb wave. t1 and t2 are selected so as to include, for example, a time region including at least the maximum amplitude in the A mode among the lines connecting the peak values of the amplitudes included in the waveform of the Lamb wave acquired in the waveform acquisition step. It may be selected so as to specify a range earlier in time than the minimum value of the line connecting the peak values of the amplitudes included in the waveform of the Lamb wave.

  Subsequently, in the determination step (step S40), the determination unit 136 determines the amount of scale based on the relationship between the A-mode attenuation rate calculated in step S30 and the amount of the deposit layer. Here, the relationship between the attenuation rate of the A mode and the amount of the deposit layer is preferably acquired in advance, and is stored in the storage device 120 as the attenuation rate-attachment amount map 70. The attenuation rate-adhesion amount map 70 may be obtained experimentally, empirically, or may be obtained by simulation or calculation. For example, the attenuation rate-attachment amount map 70 may be input from the input device 110 and stored. May be.

  FIG. 16 shows an example of the attenuation rate-adhesion amount map 70. In this attenuation rate-adhesion amount map 70, the vertical axis represents the attenuation rate and the horizontal axis represents the adhesion amount, and the tendency that the attenuation rate increases as the adhesion amount increases is shown. The determination unit 136 determines the amount of the corresponding deposit layer by applying the S-mode attenuation rate calculated in step S30 to the attenuation rate-adhesion amount map 70 acquired from the storage device 120.

  As described above, according to the present embodiment, the attenuation rate is calculated based on the A mode component of the Lamb wave propagated by the ultrasonic wave transmitted by the ultrasonic probe, and the deposit layer is calculated from the attenuation rate. Find the amount of. According to the earnest study of the present inventor, in the ultrasonic measurement method described above, the amplitude in the A mode component of the Lamb wave detected along the object to which the deposit is attached closely matches the amount of the deposit. It was found to have a strong correlation. By obtaining the amount of the deposit layer based on the correlation between the amplitude of the A mode and the amount of the deposit, it is possible to perform an accurate inspection under a wide range of conditions regardless of the component and density of the deposit layer. Become. In particular, the deposit layer on the other surface of the object to be inspected may be unevenly distributed, but even in such a case, the above configuration calculates the amount of deposit layer, Reliable inspection is possible even under various measurement conditions.

  In at least one embodiment of the present invention, an ultrasonic measurement method and an ultrasonic measurement apparatus that measure the amount of an adhering layer adhering to one surface of an object to be inspected having two opposing surfaces using ultrasonic waves Is available.

1 tube 2 scale (adhesion layer)
3 Air gap (porous)
DESCRIPTION OF SYMBOLS 10 Ultrasonic measuring device 12 Ultrasonic probe 12a Transmission probe 12b Reception probe 16a 1st support member 16b 2nd support member 18 Guide member 20 Through-hole 22 Bolt 24 Engagement hole 26 Contact sheet 28 Magnet 30 plate portion 32 bent portion 34 buffer member 36 plate portion 38 bent portion 40 fixing member 50 lines (approximate line passing between peaks)
60 Local Minimum Value 70 Attenuation Rate-Adhesion Amount Map 100 Analysis Device 110 Input Device 120 Storage Device 130 Computing Device 132 Ultrasonic Detection Unit 134 Attenuation Rate Calculation Unit 136 Determination Unit 140 Output Device

Claims (6)

Of the ultrasonic probe, a transmission probe is arranged on one surface of an object to be inspected having two opposing surfaces, and the ultrasonic probe is located at a position different from the transmission probe on the one surface. A receiving probe is arranged, and an ultrasonic wave incident on the object to be inspected from the transmitting probe is received by the receiving probe and attached to the other surface of the object to be inspected. An ultrasonic measurement method for measuring the amount of a deposit layer,
A probe installation step of installing the transmission probe and the reception probe at a predetermined distance on the one surface; and
An ultrasonic detection step of receiving a Lamb wave generated by incident ultrasonic waves from the transmission probe to the object to be inspected by the reception probe;
An attenuation rate calculating step of calculating an A mode attenuation rate of the Lamb waves received in the ultrasonic detection step;
A determination step of obtaining an amount of the deposit layer corresponding to the attenuation rate of the A mode calculated in the attenuation rate calculation step based on a relationship between the attenuation rate of the A mode and the amount of the deposit layer; Prepared ,
Wherein the predetermined distance is an ultrasonic measuring method in which the A mode included the in Lamb wave received by the receiving probe is characterized Rukoto is set to be separable from the S mode. 2. The ultrasonic wave according to claim 1 , wherein, in the probe installation step, the transmission probe is installed so that the ultrasonic wave is obliquely incident on the one surface of the tube. Measuring method. In the ultrasonic detection step, the waveform of the Lamb wave received by the reception probe is detected as an amplitude change with respect to the time axis,
In the attenuation rate calculating step, the A mode attenuation rate is calculated based on an amplitude in a time range earlier than a minimum value of a line connecting peak values of amplitudes included in the waveform of the Lamb wave. The ultrasonic measurement method according to claim 1 or 2 . In the ultrasonic detection step, the waveform of the Lamb wave received by the reception probe is detected as an amplitude change with respect to the time axis,
In the attenuation factor calculation step, the attenuation factor of the A mode is calculated based on the time integration of the amplitude in a range earlier in time than the minimum value of the line connecting the peak values of the amplitudes included in the waveform of the Lamb wave. The ultrasonic measurement method according to any one of claims 1 to 3, wherein:   Of the ultrasonic probe, a transmission probe is arranged on one surface of an object to be inspected having two opposing surfaces, and the ultrasonic probe is located at a position different from the transmission probe on the one surface. A receiving probe is arranged, and an ultrasonic wave incident on the object to be inspected from the transmitting probe is received by the receiving probe and attached to the other surface of the object to be inspected. An ultrasonic measurement method for measuring the amount of a deposit layer,
  An ultrasonic detection step of receiving a Lamb wave generated by incident ultrasonic waves from the transmission probe to the object to be inspected by the reception probe;
  An attenuation rate calculating step of calculating an A mode attenuation rate of the Lamb waves received in the ultrasonic detection step;
  A determination step of obtaining an amount of the deposit layer corresponding to the attenuation rate of the A mode calculated in the attenuation rate calculation step based on a relationship between the attenuation rate of the A mode and the amount of the deposit layer; Prepared,
  In the ultrasonic detection step, the waveform of the Lamb wave received by the reception probe is detected as an amplitude change with respect to the time axis,
  In the attenuation factor calculation step, the attenuation factor of the A mode is calculated based on the time integration of the amplitude in a range earlier in time than the minimum value of the line connecting the peak values of the amplitudes included in the waveform of the Lamb wave. An ultrasonic measurement method characterized by the above. Of the ultrasonic probe, a transmission probe is arranged on one surface of an object to be inspected having two opposing surfaces, and the ultrasonic probe is located at a position different from the transmission probe on the one surface. A receiving probe is arranged, and an ultrasonic wave incident on the object to be inspected from the transmitting probe is received by the receiving probe and attached to the other surface of the object to be inspected. An ultrasonic measuring device for measuring the amount of the deposited layer,
An ultrasonic detection unit that receives a Lamb wave generated by incident ultrasonic waves from the transmission probe to the object to be inspected by the reception probe;
An attenuation rate calculation unit for calculating an attenuation rate of the A mode among the Lamb waves received by the ultrasonic detection unit;
A determination unit that obtains the amount of the deposit layer corresponding to the attenuation factor of the A mode calculated by the attenuation rate calculation unit based on the relationship between the attenuation rate of the A mode and the amount of the deposit layer; Prepared ,
The transmission probe and the reception probe are installed at a predetermined distance on the one surface,
Wherein the predetermined distance is an ultrasonic measuring apparatus in which the A mode included the in Lamb wave received by the receiving probe is characterized Rukoto is set to be separable from the S mode.

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