JP2022030676A - Pipe internal inspection system and pipe internal inspection method - Google Patents

Abstract

To inspect a development state of rust inside a pipe in a non-destructive manner.SOLUTION: A pipe internal inspection system includes a first sensor 110A mounted on a pipe 120, a second sensor 110B mounted on the pipe 120 so as to be spaced from the first sensor 110A, and an inspection unit 150 that inspects an inside of the pipe 120 by adding vibration signals of the pipe 120 detected by the first sensor 110A and the second sensor 110B, respectively, together.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pipe internal inspection system and a pipe internal inspection method capable of non-destructively inspecting the development state of rust inside a pipe.

The rust on the inner surface caused by the aged deterioration of the water pipe rises like a bump while gradually developing, which is a factor that hinders the predetermined flow rate of the water pipe. In addition, the developed rust hump causes a decrease in pipe thickness, which is also a cause of water leakage. Furthermore, in terms of hygiene, there is concern that rust bumps may cause the development of red water and harmful bacteria.

In order to prevent these cases, or after the occurrence of these cases, regular replacement of water pipes with new pipes is often performed. However, it is burdensome to regularly replace water pipes with new ones because it requires a lot of man-hours and a lot of costs.

In order to reduce this burden, it is desirable to use a device that can non-destructively inspect the occurrence of rust lumps inside the pipe, as shown in Patent Document 1, so that the pipe can be replaced with a new pipe at an appropriate time. ..

Japanese Unexamined Patent Publication No. 61-210946

By using the non-destructive inspection method of Patent Document 1, it is possible to grasp the occurrence state of rust on the inner surface by irradiating ultrasonic waves from the outer wall of the pipe and diagnosing the pipe thickness by echo.

However, as a downside of ultrasonic diagnosis, there are problems of low reproducibility and uncertainty of measurement data due to diffused reflection due to rust in the pipe.

In order to obtain more accurate measurement data at the time of ultrasonic diagnosis, it is necessary to remove rust and paint on the outside of the pipe, or remove the heat insulating material. Is hindering the measurement work, such as being limited.

The present invention applies the phenomenon that a rust bump inside a pipe causes a vortex of water, and the vortex vibrates the pipe. By directly detecting the vibration of the pipe with a sensor, the development of rust inside the pipe can be detected. The purpose is to provide a pipe internal inspection system and a pipe internal inspection method that enable non-destructive inspection.

In the pipe internal inspection system for achieving the above object, the first sensor attached to the pipe, the second sensor attached to the pipe at a distance from the first sensor, and the first sensor and the second sensor detect each other. It has an inspection unit that inspects the inside of the pipe by adding the vibration signal of the pipe and frequency-analyzing the vibration signal after the addition.

The method of inspecting the inside of the pipe to achieve the above purpose is the stage of detecting the vibration of the pipe by the first sensor attached to the pipe and the second sensor attached to the pipe at a distance from the first sensor, and the inspection unit. This includes a step of inspecting the inside of the pipe by adding the vibration signals of the pipe detected by the first sensor and the second sensor and frequency-analyzing the added vibration signal.

According to the pipe internal inspection system configured as described above, the degree of water vortex caused by the rust lump inside the pipe is recognized by directly detecting the vibration of the pipe with the sensor. The development of rust can be inspected non-destructively.

According to the pipe internal inspection method configured as described above, the degree of water vortex caused by the rust lump inside the pipe is recognized by directly detecting the vibration of the pipe with the sensor. The development of rust can be inspected non-destructively.

It is a schematic block diagram of the pipe internal inspection system of this embodiment. It is a figure which shows the state of the inside of a pipe which does not erosion of a rust bump. It is a figure which shows the state inside the pipe where the erosion of a rust bump is seen a little. It is a figure which shows the state inside the pipe where the erosion of a rust is often seen. It is a block diagram of the 1st sensor and the 2nd sensor. It is a block diagram of a repeater. It is an operation flowchart of the pipe internal inspection system of this embodiment. It is a figure which shows the waveform of the pipe which does not erosion of a rust bump. It is a figure which shows the waveform of the pipe where the erosion of a rust bump is slightly seen. It is a figure which shows the waveform of the pipe where the erosion of a rust is often seen. It is a figure which shows the procedure of the pipe internal inspection method.

Next, an embodiment of the pipe internal inspection system and the pipe internal inspection method according to the present invention will be described in detail with reference to the drawings.

[Piping internal inspection system configuration]
FIG. 1 is a schematic configuration diagram of the pipe internal inspection system of the present embodiment. The pipe internal inspection system of the present embodiment captures the vortex of water that changes according to the condition of the rust on the inner surface of the pipe as the vibration of the pipe, frequency-analyzes the captured vibration waveform, and obtains a frequency histogram and coherent data. By doing so, the occurrence of rust bumps is visualized.

The pipe internal inspection system 100 of the present embodiment includes a first sensor 110A (sensor A), a second sensor 110B (sensor B), a repeater 130, and a computer 140 (PC) attached to the pipe 120. The repeater 130 and the computer 140 constitute an inspection unit 150.

As shown in FIG. 1, the first sensor 110A is attached to one of the pipes 120. When the first sensor 110A is attached to one of the pipes 120, it may be attached in the middle of the pipe 120 instead of the end, and magnetic force is used for the water control valve, the fire hydrant, and the air bleeding valve provided at the end of the pipe 120. May be attached. The first sensor 110A is preferably attached directly to the outer peripheral portion of the pipe 120 so that the vibration of the pipe 120 can be efficiently captured.

The second sensor 110B is attached to the other side of the pipe 120 so as to be separated from the first sensor 110A. When the second sensor 110B is attached to the other side of the pipe 120, it may be attached in the middle of the pipe 120 instead of the end, like the first sensor 110A, and the water control valve and the fire hydrant provided at the end of the pipe 120 may be attached. Or the air bleeding valve may be attached using magnetic force. The second sensor 110B is preferably attached directly to the outer peripheral portion of the pipe 120 so that the vibration of the pipe 120 can be efficiently captured. The separation distance between the second sensor 110B and the first sensor 110A is, for example, a distance of 100 m to 500 m. The separation distance between the second sensor 110B and the first sensor 110A is not limited to this distance, and may be longer or shorter than this distance.

As will be described later, the first sensor 110A and the second sensor 110B use an acceleration sensor that detects the vibration of the pipe 120 and outputs a vibration signal, and a frequency (RF) that can be used as a carrier wave for wireless communication to generate a vibration signal. It has an RF transmitter that outputs to the outside.

The inspection unit 150 is composed of a repeater 130 and a computer 140, and the repeater 130 relays a vibration signal transmitted from the first sensor 110A and the second sensor 110B to the computer 140. The computer 140 inspects the inside of the pipe 120 by adding the vibration signals of the pipe 120 detected by the first sensor 110A and the second sensor 110B, respectively, and frequency-analyzing the vibration signal after the addition. The result of the frequency analysis is displayed on the display of the computer 140.

FIG. 2A is a diagram showing a state inside the pipe without erosion of the rust bump. FIG. 2B is a diagram showing a state inside a pipe in which erosion of rust bumps is slightly observed. FIG. 2C is a diagram showing a state inside a pipe in which rust hump is often eroded.

According to the pipe internal inspection system 100 of the present embodiment, when many rust bumps 122 are present in the pipe 120 as shown in FIG. 2C, the frequency analysis of the vibration signal accompanying the vortex of water in the pipe 120 is performed. Since the result exceeds a certain value, the existence of the rust bump 122 can be easily grasped. If there is no erosion of the rust bump 122 as shown in FIG. 2A, or if there is some erosion of the rust bump 122 as shown in FIG. 2B, the result of frequency analysis of the vibration signal accompanying the vortex of water in the pipe 120 Does not exceed a certain value, so it can be determined that many rust bumps 122 do not exist in the pipe 120.

FIG. 3 is a block diagram of the first sensor 110A and the second sensor 110B. As shown in FIG. 3, the first sensor 110A and the second sensor 110B have an acceleration sensor 112 and an RF transmitter 114.

The accelerometer 112 detects the vibration of the pipe 120 and outputs a vibration signal. There are various types of accelerometers such as capacitive accelerometers, heat detection type accelerometers, and piezo resistance type accelerometers. Is used.

The RF transmitter 114 outputs a vibration signal to the outside using a frequency (RF) that can be used as a carrier wave for wireless communication. As described above, the first sensor 110A and the second sensor 110B are separated from each other by a distance of 100 m to 500 m, and the distance from the first sensor 110A and the second sensor 110B to the repeater 130 is also separated by a distance of 100 m. As the carrier frequency of wireless communication, a frequency in a frequency band capable of medium-range wireless communication is used. If a wireless LAN environment is prepared at the site, an IoT capable of wireless LAN connection may be used instead of the RF transmission unit 114.

The repeater 130 shown in FIG. 1 relays vibration signals output from RF transmission units 114 of the first sensor 110A and the second sensor 110B, respectively. Further, the computer 140 shown in FIG. 1 adds the respective vibration signals relayed by the repeater 130 and frequency-analyzes the added vibration signals to generate a rust bump 122 inside the pipe 20 (erosion state). To inspect.

FIG. 4 is a configuration diagram of the repeater 130. As shown in FIG. 4, the repeater 130 has an RF receiving unit 132 and a BT transmitting unit 134. The RF receiving unit 132 receives vibration signals output from the RF transmitting units 114 of the first sensor 110A and the second sensor 110B, respectively. The BT transmission unit 134 transmits the vibration signal received by the RF reception unit 132 to the computer 140 (see FIG. 1) using short-range wireless communication (Bluetooth (registered trademark)).

Communication is performed between the RF receiving unit 132 of the repeater 130 and the RF transmitting unit 114 of the first sensor 110A and the second sensor 110B using a frequency (RF) that can be used as a carrier wave for wireless communication. Communication is performed between the BT transmitter 134 of the repeater 130 and the computer 140 using short-range wireless communication (Bluetooth®). In the present embodiment, the repeater 130 and the computer 140 are provided separately, but the repeater 130 and the computer 140 may be integrated. In this case, short-range wireless communication (Bluetooth®) between the repeater 130 and the computer 140 becomes unnecessary.

[Operation of piping internal inspection system]
Next, the operation of the pipe internal inspection system of the present embodiment will be described in detail with reference to FIGS. 5 to 8.

In the pipe internal inspection system 100 of the present embodiment, a high-sensitivity gravity acceleration sensor that captures the vortex flow generated in the pipe 120 as vibration of the pipe 120 is installed at points A and B on the pipe 120, respectively, and a rust bump. By measuring the frequency characteristics of the vibration level data due to the eddy current that changes due to the difference in the occurrence status of 122, and comparing it with the prior vibration level data measured by the same type of piping 120 or by comparing it with the threshold value, the progress status of the rust aneurysm 122 can be checked. We are focusing on being able to diagnose. The vibration level data in advance is obtained by many experiments and used as a threshold value (constant value) for inspection.

FIG. 5 is an operation flowchart of the pipe internal inspection system of the present embodiment. FIG. 6 is a diagram showing a waveform of a pipe without erosion of rust bumps. FIG. 7 is a diagram showing a waveform of a pipe in which rust lump erosion is slightly observed. FIG. 8 is a diagram showing a waveform of a pipe in which rust hump is often eroded.

As shown in FIG. 5, first, the computer 140 receives the vibration signal of the pipe 120 detected by the first sensor 110A (sensor A) and the second sensor 110B (sensor B) via the repeater 130 (S100). ).

The vibration signal of the pipe 120 received by the computer 140 is a waveform as shown by the waveform A and the waveform B shown at the lower side of each of the drawings of FIGS. 6 to 8.

The waveform shown in FIG. 6 shows the waveform of the pipe without erosion of the rust bump 122. The waveform A shown in FIG. 6 is a waveform of a vibration signal detected by the first sensor 110A, and has a large fluctuation in a low frequency region of 300 Hz or less. The waveform B shown in FIG. 6 is the waveform of the vibration signal detected by the second sensor 110B, and like the waveform A, the fluctuation in the low frequency region of 300 Hz or less is large.

The waveform shown in FIG. 7 shows the waveform of the pipe in which the rust bump 122 is slightly eroded. The waveform A shown in FIG. 7 is a waveform of a vibration signal detected by the first sensor 110A, and has a large fluctuation in a low frequency region of 150 Hz or less. The waveform B shown in FIG. 7 is a waveform of a vibration signal detected by the second sensor 110B, and has a large fluctuation in a low frequency region of 100 Hz or less.

The waveform shown in FIG. 8 shows the waveform of the pipe in which erosion of the rust bump 122 is frequently observed. The waveform A shown in FIG. 8 is a waveform of a vibration signal detected by the first sensor 110A, and has a large fluctuation in a low frequency region of 100 Hz or less. The waveform B shown in FIG. 8 is the waveform of the vibration signal detected by the second sensor 110B, and the fluctuation in the low frequency region of 50 Hz or less is large.

Looking at the waveforms of FIGS. 6 to 8, it can be seen that as the erosion state of the rust aneurysm 122 increases, the fluctuation of the waveform shifts to the lower frequency side.

Next, the computer 140 adds the received vibration signals of the first sensor 110A (sensor A) and the second sensor 110B (sensor B), and frequency-analyzes the added vibration signal.

The waveforms of the pipe 120 frequency-analyzed by the computer 140 are the lower waveform C and the upper waveform D of the respective drawings of FIGS. 6 to 8.

The waveform shown in FIG. 6 shows the waveform of the pipe without erosion of the rust bump. The waveform C shown in FIG. 6 is a waveform representing the coherent (interference) of both vibration signals by adding the vibration signals of the first sensor 110A (sensor A) and the second sensor 110B (sensor B) and performing frequency analysis. It is a thing. The waveform C shown in FIG. 6 has large peaks near 700 Hz and around 900 Hz. Further, in the waveform D shown in FIG. 6, only a large peak is observed near the intermediate point between the first sensor 100A and the second sensor 100B, and the waveforms in the other portions are not so disturbed.

The waveform shown in FIG. 7 shows the waveform of the pipe in which rust lump erosion is slightly observed. The waveform C shown in FIG. 7 is a waveform representing the coherent (interference) of both vibration signals by adding the vibration signals of the first sensor 110A (sensor A) and the second sensor 110B (sensor B) and performing frequency analysis. It is a thing. In the waveform C shown in FIG. 7, the waveform is distorted in various frequency bands of 1700 Hz or less. Further, in the waveform D shown in FIG. 7, the waveform is disturbed at various points between the first sensor 100A and the second sensor 100B.

The waveform shown in FIG. 8 shows the waveform of a pipe in which rust hump is often eroded. The waveform C shown in FIG. 8 is a waveform representing the coherent (interference) of both vibration signals by adding the vibration signals of the first sensor 110A (sensor A) and the second sensor 110B (sensor B) and performing frequency analysis. It is a thing. The waveform C shown in FIG. 8 has a large peak near 150 Hz, and the waveform is distorted in various frequency bands over the high frequency band of 2000 Hz. Further, in the waveform D shown in FIG. 8, the waveform is disturbed at various points between the first sensor 100A and the second sensor 100B.
Looking at the waveforms of FIGS. 6 to 8, it can be seen that as the erosion of the rust aneurysm 122 increases, the degree of disorder between the waveform C and the waveform D becomes characteristic. In the present embodiment, the optimum threshold value for appropriately determining the erosion state of the rust aneurysm 122 is set by grasping such a feature. By comparing the waveform C and the waveform D after the frequency analysis with the optimum threshold value (constant value), it can be inferred how many rust bumps 122 are present inside the current pipe 120.

That is, when both the histogram of the vibration level and the coherent show low levels, it can be seen that the rust bump 122 is not formed and the new pipe state has less eddy current. If both the vibration level histogram and the coherent show an upward trend, it can be seen that the rust bump 122 is in a moderate state of occurrence. If both the vibration level histogram and coherent show a high level of large turbulence, the rust bump 122 is increasing in the pipe 120 and high level vibration is generated by the eddy current, and it is necessary to update to a new pipe. It turns out that it is a degree.

The computer 140 determines whether or not the waveform analyzed in the process of S110 has a disturbance of a certain value or more (S120). As described above, the frequency band and position where the waveform C and the waveform D are disturbed change according to the occurrence of the rust bump 122. This is determined by the threshold value.

As a result of the judgment by the computer 140, if the analyzed waveform does not have a disturbance of a certain value or more (S120: NO), there are not many rust bumps 122 inside the pipe 120, so it is judged whether or not the diagnosis is completed. (S130). If the diagnosis is not completed (S130: NO), the process returns to S100. On the other hand, when the diagnosis is completed (S130: YES), the process is terminated.

On the other hand, if the analyzed waveform has a turbulence of a certain value or more (S120: YES), it is determined that there are many rust bumps 122 inside the pipe 120 (S140). If it is determined that there are many rust bumps 122 inside the pipe 120, a display to that effect is displayed on the display of the computer 140, and the process is terminated.

As described above, according to the pipe internal inspection system 100 of the present embodiment, the frequency characteristics of the vibration level data due to the vortex changing due to the difference in the occurrence state of the rust bump 122 are measured, and the frequency characteristics of the vibration level data are measured in advance by the pipe 120 of the same type. The progress of the rust aneurysm 122 can be diagnosed by collating or comparing with the vibration level data of the above.

In the present embodiment, the progress of the rust bump 122 is diagnosed by measuring the frequency characteristic of the vibration level data associated with the vortex that changes depending on the difference in the occurrence status of the rust bump 122 and comparing it with the threshold value. However, the frequency characteristics of the prior vibration level data measured by the same type of pipe 120 and the vibration level data actually measured may be collated, and the progress of the rust bump 122 may be diagnosed according to the similarity.

In the present embodiment, the frequency histogram and coherent are obtained as the frequency analysis method, but the frequency analysis may be performed by using another method. This is because the optimal analysis method to use depends on the situation at the site.

In the present embodiment, the computer 140 determines whether or not there are many rust bumps 122 inside the pipe 120, but the display of the computer 140 displays a graph as shown in FIGS. 6 to 8. The final judgment may be made by the measurer as an auxiliary judgment by looking at this displayed graph. For very complex waveforms, the judgment of the measurer's experience can be of great help.

[Processing of piping internal inspection method]
Next, the processing of the pipe internal inspection method of the present embodiment will be described. FIG. 9 is a diagram showing a procedure of a pipe internal inspection method.

As shown in FIG. 9, first, the vibration of the pipe 120 is detected by the first sensor 110A attached to the pipe 120 and the second sensor 110B attached to the pipe 120 at a distance from the first sensor 110A (first step). ).

Next, the inspection unit 150 inspects the inside of the pipe 120 by adding the vibration signals of the pipe 120 detected by the first sensor 110A and the second sensor 110B, respectively, and frequency-analyzing the vibration signal after the addition (second). step).

The second stage is a stage of determining whether or not the analyzed waveform has a turbulence of a certain value or more as a result of frequency analysis, and a stage of determining whether or not the analyzed waveform has a turbulence of a certain value or more. If it is determined that there are many rust lumps inside and the analyzed waveform has only a disturbance of less than a certain value, it includes a step of determining that there are not many rust lumps inside the pipe 120.

The specific processing in the above stages is the same as the processing of the pipe internal inspection system 100.

As described above, according to the pipe internal inspection system 100 and the pipe internal inspection method of the present invention, the degree of water vortex caused by the rust lump inside the pipe is recognized by directly detecting the vibration of the pipe with the sensor. Therefore, the development of rust inside the pipe can be inspected non-destructively.

In addition, since the development status of rust inside the pipe can be accurately grasped, the predetermined flow rate of the water pipe is not obstructed, and there is no risk of water leakage caused by the developed rust bump. Furthermore, the outbreak of red water and harmful bacteria can be suppressed.

Furthermore, since the occurrence status of the rust bump 122 can be grasped, maintenance in the pipe and replacement of the pipe 120 can be performed at an appropriate time, and the optimum maintenance and management of the pipe 120 can be performed while minimizing the cost burden. ..

The sensor may be brought into close contact with the magnetic force from the pipe or the water control valve to acquire sound pressure data. In this case, in order to acquire more detailed sound pressure data, a water sound gravity acceleration microphone that is installed in a fire extinguishing plug or an air bleeding valve to directly acquire the underwater sound propagating to the water in the pipe may be installed.

Although the pipe internal inspection system 100 and the pipe internal inspection method of the present invention have been described above by exemplifying embodiments, the technical scope of the pipe internal inspection system 100 and the pipe internal inspection method of the present invention is the above-mentioned embodiment. It is clear that it is not limited to the range of.

100 Piping internal inspection system 110A 1st sensor 110B 2nd sensor 112 Accelerometer 114 RF transmitter 120 Piping 122 Rust
130 Repeater 132 RF Receiver 134 BT Transmitter 140 Computer 150 Inspection Unit

Claims (6)

The first sensor attached to the pipe and
A second sensor attached to the pipe at a distance from the first sensor,
An inspection unit that inspects the inside of the pipe by adding the vibration signals of the pipe detected by the first sensor and the second sensor and frequency-analyzing the vibration signal after the addition.
Has a piping internal inspection system. The first sensor and the second sensor are
An accelerometer that detects the vibration of the pipe and outputs a vibration signal,
An RF transmitter that outputs the vibration signal to the outside using a frequency (RF) that can be used as a carrier wave for wireless communication.
The piping internal inspection system according to claim 1. The inspection unit
A repeater that relays vibration signals output from the RF transmitters of the first sensor and the second sensor, respectively.
A computer that inspects the erosion state inside the pipe by adding the vibration signals relayed by the repeater and frequency-analyzing the vibration signal after the addition.
2. The pipe internal inspection system according to claim 2. The repeater is
An RF receiving unit that receives vibration signals output from the RF transmitting units of the first sensor and the second sensor, respectively.
A BT transmitter that transmits a vibration signal received by the RF receiver to the computer using short-range wireless communication (Bluetooth®).
The piping internal inspection system according to claim 3. The first step of detecting the vibration of the pipe by the first sensor attached to the pipe and the second sensor attached to the pipe at a distance from the first sensor.
The second stage in which the inspection unit inspects the inside of the pipe by adding the vibration signals of the pipe detected by the first sensor and the second sensor and frequency-analyzing the vibration signal after the addition.
Internal inspection method for piping, including. The second step is
As a result of the frequency analysis, the stage of determining whether or not the analyzed waveform has a disturbance of a certain value or more, and
If the analyzed waveform has a turbulence of a certain value or more, it is judged that there are many rust bumps inside the pipe, and if the analyzed waveform has a turbulence of less than a certain value, it is inside the pipe. At the stage of judging that there are not many rust bumps,
5. The method for inspecting the inside of a pipe according to claim 5.

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