Inspection system, inspection apparatus, inspection method, and program

Abstract

To measure pipe thickness even when there is an attachment such as rust in a pipe.SOLUTION: An inspection system includes: at least one ultrasonic sensor for transmitting ultrasonic waves inside a pipe and receiving its reflection waves; a detection propriety determination part for determining whether or not both the reflection waves reflected on the surface inside the pipe and the reflection waves reflected on the surface outside the pipe have been detected by transmission of the ultrasonic waves; and a pipe thickness calculation part for determining the thickness of the pipe from the result of the detection when it is determined that the reflection waves have been detected, and determining the thickness of the pipe from the result of detection of both the reflection waves reflected on the surface inside the pipe and the reflection waves reflected on the surface outside the pipe by transmission of the ultrasonic waves having a transmission frequency different from the transmission frequency of the ultrasonic waves, when it is determined that the reflection waves have not been detected.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to an inspection system, an inspection device, an inspection method, and a program.

Background Art

[0002] Pipes such as water pipes are underground. Therefore, when inspecting a pipe, a camera is inserted into the pipe from a fire hydrant or the like, and the presence or absence of rust or deposits on the pipe is investigated through the video taken by the camera. Further, by inserting an ultrasonic sensor into the pipe and detecting the reflected wave of the ultrasonic wave transmitted from the ultrasonic sensor toward the pipe wall, the thickness of the pipe wall (pipe thickness) can also be measured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although it is possible to measure the pipe thickness by inserting an ultrasonic sensor into the pipe, if there are deposits such as rust on the inner surface (pipe inner surface) or the outer surface (pipe outer surface) of the pipe, scattering or the like may occur depending on the frequency of the ultrasonic wave used, and as a result, it may not be possible to measure the pipe thickness.

[0005] An object of the invention is to provide an inspection system, an inspection device, an inspection method, and a program that enable measurement of the pipe thickness even when there are deposits such as rust on the pipe.

Means for Solving the Problems

[0006] The inspection system of the embodiment includes at least one ultrasonic sensor that transmits ultrasonic waves and receives the reflected waves thereof inside the pipe, a detection feasibility determination unit that determines whether it is possible to detect both the reflected wave reflected from the inner surface of the pipe and the reflected wave reflected from the outer surface of the pipe by transmitting the ultrasonic waves, and a pipe thickness calculation unit that, when it is determined that the detection has been performed, obtains the thickness of the pipe from the result of the detection, and when it is determined that the detection cannot be performed, obtains the thickness of the pipe from the result of detecting both the reflected wave reflected from the inner surface of the pipe and the reflected wave reflected from the outer surface of the pipe by transmitting ultrasonic waves having a transmission frequency different from the transmission frequency of the ultrasonic waves.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5

Figure 6A

Figure 6B

Figure 7

Figure 8A

Figure 8B

Figure 8C

Figure 9

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] <First Embodiment> First, the first embodiment will be described.

[0010] (System Configuration) FIG. 1 shows an example of the configuration of an inspection system according to the first embodiment. Note that the configuration example shown in this FIG. 1 is also used in the second embodiment described later.

[0011] The inspection system of this embodiment includes at least one ultrasonic sensor 1 and an information processing device (inspection device) 10. The ultrasonic sensor 1 and the information processing device 10 are connected by a cable C.

[0012] In the inspection of a pipe 2 such as a water pipe, the pipe thickness of the pipe 2 is measured. At least one ultrasonic sensor 1 is used for measuring the pipe thickness.

[0013] The ultrasonic sensor 1 is used in a state where it is inserted into the pipe line of the pipe 2 filled with water from the water outlet of a fire hydrant H, for example, with the cable C connected. The ultrasonic sensor 1 transmits ultrasonic waves S directed toward the pipe wall inside the pipe 2 and receives the reflected waves thereof. The ultrasonic waves S transmitted from the ultrasonic sensor 1 are incident perpendicularly to the wall surface of the pipe 2. The signal obtained by reception is transmitted to the information processing device 10 through the cable C.

[0014] Note that the ultrasonic sensor 1 may be used in a state where it is housed in the sensor head 4, but here, an example in the case where the ultrasonic sensor 1 is mainly used in a state where it is not housed in the sensor head 4 is shown.

[0015] The ultrasonic sensor 1 is attached with a skid or a tire 3. The skid or the tire 3 enables the movement of the ultrasonic sensor 1 in the longitudinal direction of the pipe 2 while maintaining the attitude of the ultrasonic sensor 1 in a stable state. Further, the ultrasonic sensor 1 is provided with a drive unit (not shown) that enables changing the direction of transmitting and receiving ultrasonic waves (for example, rotating the ultrasonic sensor 1 in the circumferential direction of the pipe 2). This drive unit operates, for example, under the control of a control unit 24 described later.

[0016] Furthermore, the ultrasonic sensor 1 is provided with a gyro sensor 11. The gyro sensor 11 measures the angle at which the ultrasonic sensor 1 is tilted in the circumferential direction of the pipe 2 with respect to a reference direction such as the vertical direction, that is, the angle (hereinafter referred to as the "rotation angle") by which the direction in which ultrasonic waves are transmitted and received rotates in the circumferential direction of the pipe 2 with respect to the reference direction. By measuring this rotation angle, the circumferential position in the pipe where the ultrasonic wave transmitted from the ultrasonic sensor 1 is incident on the wall surface can be specified. The data of the rotation angle measured by the gyro sensor 11 is transmitted to the information processing device 10 through the cable C.

[0017] On the ground, in addition to the information processing device 10, a reel R for winding the cable C and a position measuring device K are provided. The position measuring device K measures the length (hereinafter referred to as the "entry length") that the ultrasonic sensor 1 has entered in the longitudinal direction from the reference position in the pipe from the number of rotations of the roller in contact with the cable C. By measuring the entry length, the longitudinal position of the ultrasonic sensor 1 in the pipe can be specified, and further, the longitudinal position in the pipe where the ultrasonic wave transmitted from the ultrasonic sensor 1 is incident on the wall surface can be specified. The data of the entry length measured by the position measuring device K is transmitted to the information processing device 10 through the cable C'. Note that, not limited to this example, the data of the above entry length may be configured to be transmitted to the information processing device 10 through the cable C.

[0018] Note that the entry length may be obtained by another method without using the position measuring device K. For example, the entry length may be obtained by measuring the number of rotations of the reel R, or the entry length may be obtained by measuring the number of rotations of the skid or the tire 3. Further, as a method for measuring the entry length, predetermined marks may be provided at regular intervals (for example, every 1 m) on the cable C, and the entry length may be configured to be measurable by a predetermined measuring device confirming the marks.

[0019] The direction in which the ultrasonic sensor 1 transmits ultrasonic waves can be rotated 360 degrees in the circumferential direction of the pipe 2 by the above-described drive unit. Therefore, in the measurement of the pipe thickness, the ultrasonic sensor 1 can transmit ultrasonic waves in any direction, not limited to a certain direction, and can receive the reflected waves thereof.

[0020] Further, the measurement of the pipe thickness at each part of the pipe 2 may be continuously performed while moving the ultrasonic sensor 1 in the longitudinal direction of the pipe 2 and rotating it in the circumferential direction of the pipe 2, or alternatively, the pipe thickness may be measured only when it is stopped, and each time, it is moved a certain distance in the longitudinal direction of the pipe 2 or rotated a certain angle in the circumferential direction of the pipe 2, and the process of measuring the pipe thickness again in a stopped state may be repeated.

[0021] (Configuration of the information processing device 10) FIG. 2 shows an example of the configuration of the information processing device 10. Note that the configuration example shown in this FIG. 2 is also used in the second embodiment described later.

[0022] The information processing device 10 is realized by using, for example, a computer, and includes a processor 20, a transmission / reception circuit 21, a data acquisition unit 22, an input unit 23A, a display unit 23B, and the like. The information processing device 10 further includes a memory 27, a data recording unit 28, a known data holding unit 29, and the like.

[0023] Note that the information processing apparatus 10 may be arranged on the ground as shown in FIG. 1. Alternatively, it may be arranged, for example, as a microcomputer in the sensor head 4 that houses the ultrasonic sensor 1. In this case, some elements such as the input unit 23A and the display unit 23B may be arranged on the ground.

[0024] The transmission / reception circuit 21 includes a transmission circuit that applies a transmission frequency and voltage to the ultrasonic sensor 1, a reception circuit that amplifies the signal of the reflected wave received by the ultrasonic sensor 1, and a switching circuit that switches between transmission and reception. The above transmission frequency shall be controllable from the information processing apparatus 10.

[0025] The data acquisition unit 22 converts the signal amplified by the reception circuit of the transmission / reception circuit 21 into a digital value and supplies it to the processor 20. Further, the data acquisition unit 22 acquires the data of the rotation angle measured by the gyro sensor 11 and supplies it to the processor 20.

[0026] The input unit 23A corresponds to an input device such as a keyboard or a pointing device, and performs settings, changes, etc. of various information used by the processor 20 according to the input operation of the user.

[0027] The display unit 23B corresponds to a display device such as a display, and displays various information including the result of determining whether the reflected wave can be detected and the result of pipe thickness calculation processed by the processor 20.

[0028] The processor 20 has various functions such as a control unit 24, a pipe type selection unit 25A, a detection availability determination unit 25B, an ultrasonic change unit 25C, and a pipe thickness calculation unit 26. Various functions of the processor 20 are constructed as, for example, programs for realizing them on a computer.

[0029] The control unit 24 has a function of performing various controls necessary for measuring the pipe thickness, such as controlling the movement of the ultrasonic sensor 1 during pipe thickness measurement and controlling the processing of the transmission / reception circuit 21.

[0030] For example, based on the data of the penetration length measured by the position measuring device K and the data of the rotation angle measured by the gyro sensor 11, the control unit 24 grasps the position of the pipe wall to be measured for the pipe thickness (that is, the position in the pipeline where the ultrasonic wave transmitted from the ultrasonic sensor 1 is incident on the wall surface), and can control the movement of the ultrasonic sensor 1 and measure the pipe thickness. Further, based on the data supplied from the data acquisition unit 22 to the processor 20, the control unit 24 can form an image showing the measurement result by the ultrasonic sensor 1 and display the image on the display unit 23B.

[0031] The pipe type selection unit 25A has a function of selecting the pipe type of the pipe 2 to be measured for the pipe thickness from among a plurality of pipe types. The pipe type includes items such as the type of lining, nominal diameter, and pipe thickness.

[0032] The detection possibility determination unit 25B has a function of determining whether or not it is possible to detect both the reflected wave reflected from the inner surface (pipe inner surface) of the pipe 2 and the reflected wave reflected from the outer surface (pipe outer surface) of the pipe 2 by transmitting ultrasonic waves from the ultrasonic sensor 1 for the pipe type selected by the pipe type selection unit 25A.

[0033] When it is determined by the detection possibility determination unit 25B that the above detection cannot be performed, the ultrasonic wave change unit 25C has a function of notifying the operator through the display unit 23B or the like that the transmission frequency of the ultrasonic wave should be changed (for example, that the ultrasonic sensor in use should be changed to an ultrasonic sensor with a different transmission frequency). When the transmission frequency of the ultrasonic wave should be changed, for example, the ultrasonic sensor 1 in use is taken out of the pipeline, and an ultrasonic sensor 1 with a different transmission frequency is introduced into the pipeline.

[0034] The types of available transmission frequencies may be, for example, three types (e.g., 5 MHz, 3 MHz, 1 MHz). For example, if the above detection cannot be performed at a transmission frequency of 5 MHz, a change to 3 MHz may be implemented (lowering the transmission frequency). If the above detection cannot be performed at a transmission frequency of 3 MHz, a change to 1 MHz may be implemented (lowering the transmission frequency). Note that the types of available transmission frequencies are not limited to three types, and may be two types (e.g., 5 MHz, 1 MHz) or four or more types.

[0035] For example, the control unit 24 controls the transmission of ultrasonic waves having a first frequency (e.g., 5 MHz) and the reception of the reflected waves thereof. When the detection of both the ultrasonic waves having the first frequency and the reflected waves thereof cannot be performed, the control unit 24 may control the transmission of ultrasonic waves having a second frequency (e.g., 1 MHz) lower than the first frequency and the reception of the reflected waves thereof.

[0036] Also, the control unit 24 controls the transmission of ultrasonic waves having a first frequency (e.g., 5 MHz) and the reception of the reflected waves thereof. When the detection of both the ultrasonic waves having the first frequency and the reflected waves thereof cannot be performed, the control unit 24 controls the transmission of ultrasonic waves having a second frequency (e.g., 3 MHz) lower than the first frequency and the reception of the reflected waves thereof. When the detection of both the ultrasonic waves having the second frequency and the reflected waves thereof cannot be performed, the control unit 24 may control the transmission of ultrasonic waves having a third frequency (e.g., 1 MHz) lower than the second frequency and the reception of the reflected waves thereof.

[0037] When the detection permission determination unit 25B determines that the above detection can be performed, the pipe thickness calculation unit 26 obtains the thickness of the pipe 2 from the result of the above detection. When it is determined that the above detection cannot be performed, the pipe thickness calculation unit 26 is a function of obtaining the thickness of the pipe 2 from the result of detecting both the reflected waves reflected from the inner surface of the pipe 2 and the reflected waves reflected from the outer surface of the pipe by transmitting ultrasonic waves having a transmission frequency different from the above transmission frequency.

[0038] The memory 27 stores programs, data, etc. used by the processor 20 to measure the pipe thickness.

[0039] The data recording unit 28 records data acquired by the data acquisition unit 22 (including data on the rotation angle measured by the gyro sensor 11), data on the penetration length measured by the position measuring device K, data indicating the pipe type selected by the pipe type selection unit 25A, the result determined by the detection possibility determination unit 25B, data on the pipe thickness calculated by the pipe thickness calculation unit 26, and the like.

[0040] The known data holding unit 29 stores known data such as the pipe thickness in a normal state (a state without deposits such as rust) for each pipe type, the arrival time (or reception timing) and signal level of each of the reflected waves on the inner surface and outer surface of the pipe 2 after ultrasonic transmission, the sound velocity of the pipe, and information indicating the relationship between the sound velocity and temperature.

[0041] (Measurement of Pipe Thickness Based on Reflected Waves) Fig. 3 shows the characteristics of various reflected waves received after ultrasonic waves are transmitted from the ultrasonic sensor 1 toward the pipe wall.

[0042] In the graph of Fig. 3, the horizontal axis represents the time after ultrasonic transmission, and the vertical axis represents the signal level of the received reflected wave. The reflected waves W1, W2, and W3 in the graph of Fig. 3 are reflected waves with different arrival times received by the ultrasonic sensor 1 after ultrasonic waves are transmitted from the ultrasonic sensor 1 toward the pipe wall. The reflected wave W1 is a reflected wave reflected from the inner surface of the pipe 2, the reflected wave W2 is a reflected wave reflected from the outer surface of the pipe 2, and the reflected wave W3 is a reflected wave multiply reflected on the outer surface of the pipe 2 (a reflected wave that is reflected from the outer surface of the pipe 2 and then reflected from the inner surface of the pipe 2 and then reflected again from the outer surface of the pipe 2, etc.).

[0043] Here, if the signal levels of the reflected wave W1 and the reflected wave W2 received by the ultrasonic sensor 1 are each equal to or greater than a certain level, the reflected wave W1 and the reflected wave W2 can be detected, and the thickness of the pipe 2 can be measured from the time difference Δt between the arrival time of the reflected wave W1 and the arrival time of the reflected wave W2.

[0044] The signals of each reflected wave with a time difference received by the ultrasonic sensor 1 are transmitted from the ultrasonic sensor 1 to the information processing device 10 and are transmitted to the processor 20 via the transmission / reception circuit 21 and the data acquisition unit 22 shown in FIG. 2.

[0045] In the processor 20, the detection feasibility determination unit 25B determines whether both of the reflected waves W1 and W2 having a signal level equal to or higher than a certain value can be detected for the pipe type selected by the pipe type selection unit 25A.

[0046] For example, the detection feasibility determination unit 25B acquires data on the signal level and arrival time for signals having a signal level equal to or higher than a certain value among the signals received by the ultrasonic sensor 1, and compares the data with the known data in the known data holding unit 29 (specifically, the signal levels and arrival time data of the normal reflected waves W1 and W2 corresponding to the pipe type selected by the pipe type selection unit 25A), and attempts to identify the type of each reflected wave by checking the degree of agreement between the two.

[0047] If the reflected waves W1 and W2 can be identified in this way, the detection feasibility determination unit 25B determines that both of the reflected waves W1 and W2 can be detected. Further, in this case, since the time difference Δt can be obtained from the arrival time of the reflected wave W1 and the arrival time of the reflected wave W2, it is determined that the pipe thickness can be calculated. In this case, the pipe thickness calculation unit 26 obtains the time difference Δt from the arrival time of the reflected wave W1 and the arrival time of the reflected wave W2, and calculates the pipe thickness using the sound speed data (specifically, the sound speed data corresponding to the pipe type selected by the pipe type selection unit 25A) included in the known data in the known data holding unit 29. The pipe thickness is obtained by multiplying the time difference Δt by the sound speed.

[0048] On the other hand, if the reflected wave W2 that should appear after the reflected wave W1 has been identified cannot be identified, the detection determination unit 25B determines that neither of the reflected waves W1 and W2 could be detected. Furthermore, in this case, since the time difference Δt cannot be obtained, the detection determination unit 25B determines that the pipe thickness cannot be calculated. In this case, the ultrasonic wave change unit 25C notifies the operator through the display unit 23B or the like that the transmission frequency of the ultrasonic wave in use should be changed (for example, that the ultrasonic wave sensor in use should be changed to an ultrasonic wave sensor with a different transmission frequency). Note that when the ultrasonic wave sensor 1 in use has a function of individually transmitting a plurality of ultrasonic waves with different transmission frequencies, the ultrasonic wave change unit 25C may instruct the transmission-reception circuit 21 to change the transmission frequency in use.

[0049] FIG. 4A shows an example of an image showing a part of the measurement result when the reflected wave W1 can be detected but the reflected wave W2 cannot be detected. FIG. 4B shows an example of an image showing a part of the measurement result when both of the reflected waves W1 and W2 can be detected.

[0050] Both FIG. 4A and FIG. 4B are examples of images showing a part of the measurement result by the ultrasonic wave sensor 1. In the images of FIG. 4A and FIG. 4B, the horizontal axis indicates the time after the ultrasonic wave is transmitted from the inside to the outside of the pipe 2, and the vertical axis indicates the position in the longitudinal direction of the pipe 2.

[0051] When the transmission frequency of the ultrasonic wave sensor 1 is 5 MHz, as shown in FIG. 4A, a long white band extending in the longitudinal direction of the pipe 2 is confirmed. This corresponds to the reflected wave W1. However, in the region P1 on the right side of this reflected wave W1, a long white band extending in the longitudinal direction of the pipe 2 is expected to appear as the reflected wave W2, but it does not appear.

[0052] In such a case, lower the transmission frequency of the ultrasonic sensor 1 to, for example, 1 MHz. As a result, as shown in FIG. 4B, a white strip corresponding to the reflected wave W1 appears, and a white strip corresponding to the reflected wave W2 appears in the region P2. In this case, since the arrival times of the reflected wave W1 and the reflected wave W2 are known, the time difference Δt between the two can be obtained, and the pipe thickness can be calculated from this time difference Δt and the speed of sound.

[0053] The reason why the reflected wave W2 cannot be detected at 5 MHz is that the ultrasonic waves are scattered due to the presence of rust or the like adhering to the inside and outside of the pipe wall. By lowering the transmission frequency, the influence of scattering by deposits such as rust is reduced, so that the reflected wave W2 can be detected.

[0054] (Modification example of ultrasonic sensor) Next, a modification example of the ultrasonic sensor 1 will be described with reference to FIGS. 5, 6A, and 6B.

[0055] · Focusing type ultrasonic sensor FIG. 5 shows a modification example of the ultrasonic sensor 1.

[0056] As shown in FIG. 5, the ultrasonic sensor 1 may be a focusing type ultrasonic sensor that focuses the beam of ultrasonic waves transmitted. By using a focusing type ultrasonic sensor, the irradiation area of the ultrasonic waves on the pipe wall of the pipe 2 can be narrowed, the irradiation intensity per unit area can be improved, and the reflected wave W2 can be detected more easily.

[0057] · Wideband type ultrasonic sensor Further, the ultrasonic sensor 1 may be configured as a single broadband ultrasonic sensor capable of transmitting a plurality of ultrasonic waves having different transmission frequencies. The broadband ultrasonic sensor is, for example, a broadband ultrasonic sensor in the range of 1 to 5 MHz that includes a plurality of different transmission frequencies. By using the broadband ultrasonic sensor, ultrasonic waves with different transmission frequencies can be transmitted and received separately or simultaneously by one ultrasonic sensor. Therefore, it is not necessary to prepare a plurality of ultrasonic sensors. Also, when the pipe thickness cannot be measured using a certain transmission frequency, the transmission frequency in use can be changed to another transmission frequency to measure the pipe thickness.

[0058] · An ultrasonic sensor including one transmitting part and a plurality of receiving parts FIGS. 6A and 6B show another modification of the ultrasonic sensor 1.

[0059] As shown in FIG. 6A, the ultrasonic sensor 1 may be configured to include one transmitting part 1a that transmits ultrasonic waves and a plurality of receiving parts 1b that can receive reflected waves of the ultrasonic waves transmitted by the transmitting part 1a. The one transmitting part 1a and the plurality of receiving parts 1b shown in FIG. 6A are in a form in which the plurality of receiving parts 1b are arranged so as to surround the transmitting part 1a as shown in FIG. 6B when viewed in the radial direction of the pipe 2. Note that the number of transmitting parts 1a is not limited to one, and a plurality of transmitting parts 1a may be provided.

[0060] Also, the one transmitting part 1a and the plurality of receiving parts 1b may each be realized by a single ultrasonic sensor 1. In that case, the configuration may be such that the role of each ultrasonic sensor 1 can be individually switched in the transmission / reception circuit 21 or the like. That is, the ultrasonic sensor 1 that was functioning as the transmitting part 1a may be changed to function as the receiving part 1b, or the ultrasonic sensor 1 that was functioning as the transmitting part 1a may be changed to function as the receiving part 1b.

[0061] By adopting such a structure, even if the reflected wave of the ultrasonic wave is scattered on the inner surface or outer surface of the pipe, the reflected wave can be easily detected.

[0062] (Operation example) Next, with reference to the flowchart of FIG. 7, an example of the operation of pipe thickness measurement according to the first embodiment will be described.

[0063] Note that the operation example shown here is just an example and is not limited to this example, and can be appropriately modified and implemented. For example, the measurement of the pipe thickness at each part of the pipe 2 may be continuously performed while moving the ultrasonic sensor 1 in the longitudinal direction of the pipe 2 and rotating it in the circumferential direction of the pipe 2, or the pipe thickness may be measured only when it is stopped, and each time, it is moved a certain distance in the longitudinal direction of the pipe 2 or rotated a certain angle in the circumferential direction of the pipe 2, and the process of measuring the pipe thickness again in the stopped state may be repeated. FIG. 7 shows the latter operation example.

[0064] First, the pipe type selection unit 25A selects the pipe type to be measured (step S10).

[0065] Next, under the control of the control unit 24, the ultrasonic sensor 1 is automatically or manually moved (linear movement in the longitudinal direction of the pipe 2 and / or rotational movement in the circumferential direction) so that ultrasonic waves are irradiated onto the position of the pipe wall to be measured (step S11), and the ultrasonic sensor 1 transmits ultrasonic waves and receives reflected waves (step S12). The signal obtained by the above reception is transmitted to the information processing device 10 through the cable C.

[0066] For example, the control unit 24 grasps the position of the pipe wall to be measured (that is, the position in the pipeline where the ultrasonic wave transmitted from the ultrasonic sensor 1 is incident on the wall surface) from the data of the penetration length measured by the position measuring device K and the data of the rotation angle measured by the gyro sensor 11, and performs control such as rotating the ultrasonic sensor 1 by a predetermined amount so that ultrasonic waves are irradiated onto the position of the pipe wall from which the pipe thickness is to be measured.

[0067] Incidentally, assume that the transmission frequency of the ultrasonic sensor 1 at this time is, for example, 5 MHz. The above transmission frequency may be determined based on, for example, the result of previously inspecting with a camera and visually confirming the rust on the inner surface.

[0068] Next, the detection determination unit 25B acquires the arrival time of each reflected wave indicated in the received signal (step S13), and determines whether or not two reflected waves corresponding to the pipe thickness according to the above pipe type can be detected (step S14).

[0069] When it is determined that the above detection has been performed (Yes in step S14), the pipe thickness calculation unit 26 calculates the time difference between the arrival times of the two reflected waves from the structure of the above pipe type (step S15), and further measures the thickness of the pipe 2 from the time difference and the sound speed (step S16). The data indicating the measured thickness is transmitted to the information processing device 10 through the cable C. Then, the process proceeds to step S18.

[0070] On the other hand, in step S14, when it is determined that the above detection cannot be performed (No in step S14), the ultrasonic change unit 25C notifies the operator through the display unit 23B or the like that the transmission frequency of the ultrasonic wave should be changed (for example, that the ultrasonic sensor in use should be changed to an ultrasonic sensor with a different transmission frequency).

[0071] The change of the ultrasonic sensor 1 is performed after storing the data of the entry length measured by the position measuring device K and the data of the rotation angle measured by the gyro sensor 11 in the data recording unit 28. Assume that the transmission frequency of the changed ultrasonic sensor 1 is, for example, 3 MHz. Then, based on the data of the entry length and the data of the rotation angle stored in the data recording unit 28, the changed ultrasonic sensor 1 is moved to the position where the previous ultrasonic sensor 1 was, and ultrasonic waves are transmitted and reflected waves are received by the changed ultrasonic sensor 1 (step S17). The signal obtained by the above reception is transmitted to the information processing device 10 through the cable C.

[0072] In the subsequent steps S13’ to S17’, the same processing as the above-described steps S13 to S17 is performed. However, in step S17’, the ultrasonic sensor 1 in use is changed to the ultrasonic sensor 1 with a transmission frequency of 1 MHz. In the subsequent steps S13” to S16” as well, the same processing is performed.

[0073] In step S18, if the inspection is not terminated (No in step S18), the processing from step S11 is repeated. If the inspection is terminated (Yes in step S18), all processing is terminated.

[0074] According to the first embodiment, when the pipe thickness cannot be measured using a certain ultrasonic sensor, by changing to an ultrasonic sensor with a different transmission frequency and measuring the pipe thickness, it becomes possible to measure the pipe thickness even when there are deposits such as rust on the pipe.

[0075] <Second Embodiment> Next, the second embodiment will be described. Hereinafter, the description will focus on the parts different from the first embodiment.

[0076] (System Configuration) The configuration of the inspection system according to the second embodiment and the configuration of the information processing apparatus 10 are the same as those shown in FIG. 1.

[0077] FIGS. 8A and 8B show an example of the configuration of the sensor head 4 according to the second embodiment. In FIGS. 8A and 8B, the same reference numerals are given to the elements common to the above-described first embodiment.

[0078] In the second embodiment, the ultrasonic sensor 1 described above is configured as a plurality of ultrasonic sensors 1A, 1B, and 1C that transmit a plurality of ultrasonic waves with different transmission frequencies. The structures and functions of the ultrasonic sensors 1A, 1B, and 1C are the same as those of the ultrasonic sensor 1 described above. Also, in the second embodiment, the gyro sensor 11 is used. The transmission frequencies of the ultrasonic sensors 1A, 1B, and 1C are, for example, 5 MHz, 3 MHz, and 1 MHz, respectively. The gyro sensor 11 measures the rotation angle of the sensor head 4 or the rotation angle of the ultrasonic sensor in use.

[0079] In the second embodiment, the ultrasonic sensors 1A, 1B, and 1C are used in a state of being housed in the sensor head 4.

[0080] As shown in Fig. 8A, the sensor head 4 includes a plurality of ultrasonic sensors 1A, 1B, and 1C, a bearing 5, a rotation motor (drive unit) 6, a gear 7, a temperature sensor 8, a rotating part 9, and a gyro sensor 11. The ultrasonic sensors 1A, 1B, and 1C shown in Fig. 8A are arranged as shown in Fig. 8B when viewed from the longitudinal direction of the tube 2. The ultrasonic sensors 1A, 1B, and 1C are arranged on a rotating part 9 that can perform a rotating operation. The rotating part 9 is held by the bearing 5. Also, a rotary connector or the like may be additionally provided on the support part of the rotating part 9 so that the rotating operation can be performed smoothly. Also, the forward and reverse rotations of the rotating part 9 may be repeatedly performed electrically by the rotation motor 6 through a robot cable or the like.

[0081] Of the three positions where the ultrasonic sensors 1A, 1B, and 1C are arranged in Fig. 8B, it is assumed that the position where the ultrasonic sensor 1C is arranged is the only position (reference position) where ultrasonic wave transmission and reception can be performed. In the example of Fig. 8B, the ultrasonic sensor 1C is in a state where ultrasonic wave transmission and reception can be performed.

[0082] The ultrasonic wave transmitted from the ultrasonic sensor located at the reference position is incident perpendicularly to the wall surface of the pipe 2. In this case, the ultrasonic wave transmitted from the ultrasonic sensor may proceed in the longitudinal direction of the pipe 2 and be reflected by 90° by a mirror (not shown) so as to be incident perpendicularly to the wall surface of the pipe 2, or the ultrasonic wave transmitted from the ultrasonic sensor may be configured to be directly incident perpendicularly to the wall surface of the pipe 2.

[0083] The rotation motor 6 can obtain information on the rotation angle of the rotating part 9 with an origin switch or a rotary encoder, and can rotate the rotating part 9 via the gear 7 so that any one of the plurality of ultrasonic sensors 1A, 1B, 1C can transmit and receive ultrasonic waves at the above reference position. The rotation motor 6 is controlled by a control unit 24 in a processor 20 of the information processing device 10.

[0084] The temperature sensor 8 measures the water temperature. A pipe thickness calculation unit 26 in the processor 20 of the information processing device 10 has a function of obtaining the speed of sound of ultrasonic waves according to the temperature measured by the temperature sensor 8 and obtaining the thickness of the pipe 2 using this speed of sound. When obtaining the speed of sound, information (such as information indicating the relationship between the speed of sound and temperature) stored in the known data holding unit 29 is used.

[0085] (Modification example of ultrasonic sensor) FIG. 8C shows a modification example of the ultrasonic sensor 1.

[0086] As shown in FIG. 8C, the ultrasonic sensors 1A, 1B, 1C are arranged side by side in the longitudinal direction of the pipe 2. The ultrasonic sensors 1A, 1B, 1C may be configured to transmit and receive ultrasonic waves at different timings, or may be configured to transmit and receive ultrasonic waves at the same timing.

[0087] By adopting such a structure, it is not necessary to provide mechanisms such as the bearing 5, the rotation motor 6, the gear 7, and the rotating part 9 described above.

[0088] (Operation example) Next, with reference to the flowchart of FIG. 9, an example of the operation of pipe thickness measurement according to the second embodiment will be described.

[0089] Note that the same reference numerals are given to the steps that are the same as the operation of pipe thickness measurement according to the first embodiment described above. The steps that are significantly different from the first embodiment are steps S27, S27' and steps S26, S26', S26".

[0090] It is assumed that among the ultrasonic sensors 1A, 1B, and 1C, the ultrasonic sensor 1A with a transmission frequency of 5 MHz is located at the above reference position.

[0091] First, in the same manner as in the first embodiment described above, the pipe type selection unit 25A selects the pipe type to be measured (step S10).

[0092] Next, under the control of the control unit 24, the sensor head 4 is moved automatically or manually so that ultrasonic waves are irradiated onto the position of the pipe wall to be measured (step S11). For example, transmission of ultrasonic waves and reception of reflected waves are performed by the ultrasonic sensor 1A (step S12). The signal obtained by the above reception is transmitted to the information processing device 10 through the cable C.

[0093] For example, the control unit 24 grasps the position of the pipe wall to be measured (that is, the position in the pipeline where the ultrasonic waves transmitted from the ultrasonic sensor 1A are incident on the wall surface) from the data of the penetration length measured by the position measuring instrument K and the data of the rotation angle measured by the gyro sensor 11, and controls the sensor head 4 to rotate by a predetermined amount so that ultrasonic waves are irradiated onto the position of the pipe wall from which the pipe thickness is to be measured.

[0094] Next, the detection availability determination unit 25B acquires the arrival time of each reflected wave indicated by the received signal (step S13), and determines whether or not two reflected waves corresponding to the pipe thickness corresponding to the above pipe type can be detected (step S14).

[0095] When it is determined that the above detection has been performed (Yes in step S14), the pipe thickness calculation unit 26 calculates the time difference between the arrival times of the two reflected waves from the structure of the above pipe type (step S15), and further measures the thickness of pipe 2 from the time difference and the sound velocity corresponding to the temperature measured by the temperature sensor 8 (step S26). The data indicating the measured thickness is transmitted to the information processing device 10 through the cable C. Then, the process proceeds to step S18.

[0096] On the other hand, in step S14, when it is determined that the above detection cannot be performed (No in step S14), the ultrasonic wave change unit 25C notifies the operator through the display unit 23B or the like that the transmission frequency of the ultrasonic wave should be changed (for example, that the currently used ultrasonic sensor should be changed to an ultrasonic sensor with a different transmission frequency).

[0097] The change of the ultrasonic sensor 1A may be realized by the control unit 24 automatically judging and controlling the rotation motor 6, or may be realized by the operation of the user.

[0098] Assume that the ultrasonic sensor after the change is the ultrasonic sensor 1B with a transmission frequency of 3 MHz.

[0099] For example, under the control of the control unit 24, when the rotation motor 6 rotates the rotating part 9 so that the ultrasonic sensor located at the reference position becomes the ultrasonic sensor 1B, the ultrasonic wave is transmitted by the changed ultrasonic sensor 1B and the reflected wave is received (step S27). The signal obtained by the above reception is transmitted to the information processing device 10 through the cable C.

[0100] In the subsequent steps S13’~S15’, S26’, S27’, the same processing as that in the above steps S13’~S15’, S26’, S27’ is performed. However, in step S27’, the rotating part 9 is rotated so that the ultrasonic sensor located at the reference position becomes the ultrasonic sensor 1C with a transmission frequency of 1 MHz. In the subsequent steps S13”~S15”, S26” as well, the same processing is performed.

[0101] In step S18, if the inspection is not completed (No in step S18), the process from step S11 is repeated. If the inspection is completed (Yes in step S18), all processes are terminated.

[0102] According to the second embodiment, when the pipe thickness cannot be measured using a certain ultrasonic sensor, there is no need to perform a process of taking out the ultrasonic sensor 1 in use outside the pipeline and introducing an ultrasonic sensor 1 with a different transmission frequency into the pipeline. Instead of using ultrasonic sensors with different transmission frequencies, the pipe thickness can be measured, and it is possible to measure the pipe thickness even when there are deposits such as rust on the pipe.

[0103] As described in detail above, according to the embodiment, it is possible to measure the pipe thickness even when there are deposits such as rust on the pipe.

[0104] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0105] 1... Ultrasonic sensor, 2... Pipe, 3... Skid (or tire), 4... Sensor head, 5... Bearing, 6... Rotation motor (drive unit), 7... Gear, 8... Temperature sensor, 9... Rotating part, 10... Information processing device (inspection device), 11... Gyro sensor, 20... Processor, 21... Transceiver circuit, 22... Data acquisition unit, 23A... Input unit, 23B... Display unit, 24... Control unit, 25A... Pipe type selection unit, 25B... Detection availability determination unit, 25C... Ultrasonic change unit, 26... Pipe thickness calculation unit, 27... Memory, 28... Data recording unit, 29... Known data holding unit, C... Cable.

Claims

1. At least one ultrasonic sensor that transmits ultrasonic waves and receives the reflected waves thereof inside the pipe, A detection feasibility determination unit that determines whether it is possible to detect both the reflected wave reflected by the inner surface of the pipe and the reflected wave reflected by the outer surface of the pipe by transmitting the ultrasonic waves, A pipe thickness calculation unit that, when it is determined that the detection has been performed, obtains the thickness of the pipe from the result of the detection, and when it is determined that the detection cannot be performed, transmits ultrasonic waves having a transmission frequency different from the transmission frequency of the ultrasonic waves, and obtains the thickness of the pipe from the result of detecting both the reflected wave reflected by the inner surface of the pipe and the reflected wave reflected by the outer surface of the pipe An inspection system comprising.

2. The inspection system according to claim 1, wherein the ultrasonic sensor includes an ultrasonic sensor that focuses the ultrasonic beam to be transmitted.

3. The inspection system according to claim 1 or 2, wherein the ultrasonic sensor is configured as a single ultrasonic sensor capable of transmitting a plurality of ultrasonic waves having different transmission frequencies.

4. The inspection system according to any one of claims 1 to 3, wherein the ultrasonic sensor includes a transmission unit that transmits ultrasonic waves and a plurality of reception units capable of receiving reflected waves with respect to the ultrasonic waves transmitted by the transmission unit.

5. The inspection system according to claim 1 or 2, wherein the ultrasonic sensor is configured as a plurality of ultrasonic sensors that transmit a plurality of ultrasonic waves having different transmission frequencies.

6. A rotating unit on which the plurality of ultrasonic sensors are arranged, A drive unit that rotates the rotating unit so that any one of the plurality of ultrasonic sensors transmits and receives ultrasonic waves at a predetermined position, The inspection system according to claim 5, further comprising.

7. The inspection system according to claim 5, wherein the plurality of ultrasonic sensors are arranged side by side in the longitudinal direction of the pipe.

8. Further comprising a temperature sensor that measures the temperature of the medium flowing inside the pipe, The inspection system according to any one of claims 1 to 7, wherein the pipe thickness calculation unit obtains the speed of sound of ultrasonic waves according to the temperature measured by the temperature sensor, and obtains the thickness of the pipe using the speed of sound.

9. A control unit that controls the operation of at least one ultrasonic sensor to transmit ultrasonic waves and receive the reflected waves thereof inside the pipe, A detection feasibility determination unit that determines whether both a reflected wave reflected from the inner surface of the pipe and a reflected wave reflected from the outer surface of the pipe can be detected by transmitting the ultrasonic wave; a pipe thickness calculation unit that, when it is determined that the detection has been performed, obtains the thickness of the pipe from the result of the detection, and when it is determined that the detection cannot be performed, transmits an ultrasonic wave having a transmission frequency different from the transmission frequency of the ultrasonic wave, and obtains the thickness of the pipe from the result of detecting both a reflected wave reflected from the inner surface of the pipe and a reflected wave reflected from the outer surface of the pipe; An inspection device comprising:

10. The control unit controls the transmission of ultrasonic waves having a first frequency and the reception of the reflected waves thereof, and when both the ultrasonic waves having the first frequency and the reflected waves thereof cannot be detected, controls the transmission of ultrasonic waves having a second frequency lower than the first frequency and the reception of the reflected waves thereof. The inspection device according to claim 9.

11. The control unit controls the transmission of ultrasonic waves having a first frequency and the reception of the reflected waves thereof, and when both the ultrasonic waves having the first frequency and the reflected waves thereof cannot be detected, controls the transmission of ultrasonic waves having a second frequency lower than the first frequency and the reception of the reflected waves thereof, and when both the ultrasonic waves having the second frequency and the reflected waves thereof cannot be detected, controls the transmission of ultrasonic waves having a third frequency lower than the second frequency and the reception of the reflected waves thereof. The inspection device according to claim 9.

12. Controlling, by a control unit, an operation in which at least one ultrasonic sensor transmits and receives ultrasonic waves inside a pipe; determining whether both a reflected wave reflected from the inner surface of the pipe and a reflected wave reflected from the outer surface of the pipe can be detected by transmitting the ultrasonic wave; when it is determined that the detection has been performed, obtaining the thickness of the pipe from the result of the detection by a pipe thickness calculation unit, and when it is determined that the detection cannot be performed, obtaining the thickness of the pipe from the result of detecting both a reflected wave reflected from the inner surface of the pipe and a reflected wave reflected from the outer surface of the pipe by transmitting an ultrasonic wave having a transmission frequency different from the transmission frequency of the ultrasonic wave; An inspection method comprising:

13. On a computer A function for controlling the operation of at least one ultrasonic sensor to transmit ultrasonic waves and receive the reflected waves thereof inside the pipe, A function for determining whether both the reflected wave reflected from the inner surface of the pipe and the reflected wave reflected from the outer surface of the pipe can be detected by the transmission of the ultrasonic waves, When it is determined that the detection can be performed, the thickness of the pipe is obtained from the result of the detection, and when it is determined that the detection cannot be performed, the ultrasonic waves having a transmission frequency different from the transmission frequency of the ultrasonic waves are transmitted, and the thickness of the pipe is obtained from the result of detecting both the reflected wave reflected from the inner surface of the pipe and the reflected wave reflected from the outer surface of the pipe A program for realizing the above.

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