WO2024252618A1 - Continuity inspection system for underground buried pipeline - Google Patents

Abstract

The present disclosure is a system comprising: a speaker that outputs sound waves which can propagate through a pipeline; a microphone that detects the sound waves from the pipeline; and a determination device that determines the continuity of the pipeline on the basis of results of the detection by the microphone.

Description

Underground pipeline continuity inspection system

This disclosure relates to technology for testing continuity of underground pipes.

Due to the increasing demand for Internet traffic in recent years, new fiber optic cables capable of faster communication are being installed and replaced. Fiber optic cables are installed on utility poles or in conduits, and are provided from the station to each home, etc.

Because the pipelines are laid underground, dirt and water can accumulate inside them, and cracks can appear. Water that accumulates inside the pipeline or moisture in the ground can also cause corrosion. These factors can cause the electrical conductivity inside the pipeline to deteriorate.

　Previously, pipe cameras were used to check for abnormalities in pipes to check the state of continuity (see, for example, Non-Patent Document 1).

Ito et al., "Method for predicting corrosion on the inner surface of communication pipes using machine learning based on inspection results," AI and Data Science Papers, Vol. 3, No. J2, 2022

　Sometimes, soil, water, etc. may get into the pipeline. For this reason, the camera in Non-Patent Document 1 may not be able to capture clear images, and the condition inside the pipeline may not be properly understood. In addition, the continuity inspection in Non-Patent Document 1 requires a worker to enter a manhole connecting the pipeline to the ground and insert a pipe camera into the pipeline, which requires work.

The purpose of this disclosure is to make it possible to perform continuity testing of a pipeline without inserting a pipe camera into the pipeline.

The system of the present disclosure comprises:
A speaker that outputs a sound wave that can propagate through the pipe;
a microphone for detecting the sound waves from the pipe;
a determination device that determines continuity of the pipeline based on a detection result by the microphone;
and performing the method of the present disclosure.

The system disclosed herein can employ a first aspect in which the speaker and the microphone are installed at both ends of the pipeline. In this aspect, the speaker outputs sound waves that can propagate the entire length of the pipeline. The microphone detects the sound waves after they have propagated the entire length of the pipeline.

The system disclosed herein may adopt a second aspect in which the speaker and the microphone are installed at one end of the pipeline. In this aspect, the speaker outputs sound waves that can travel back and forth through the pipeline. The microphone may detect sound waves reflected by an obstacle in the pipeline.

The determination device may determine the continuity of the pipe based on the sound volume detected by the microphone. In this case, in the first aspect, the continuity is determined when the sound volume detected by the microphone is greater than a predetermined threshold, and the non-continuity is determined when the sound volume detected by the microphone is equal to or less than the threshold. In the second aspect, the continuity is determined when the sound volume detected by the microphone is less than a predetermined threshold, and the non-continuity is determined when the sound volume detected by the microphone is equal to or greater than the threshold.

The above disclosures may be combined whenever possible.

This disclosure makes it possible to inspect the continuity of pipelines between manholes without inserting a pipe camera into the pipeline.

1 is an example embodiment of a system of the present disclosure. 13 shows an example of a determination flow. 1 is an example embodiment of a system of the present disclosure. 1 is an example embodiment of a system of the present disclosure. 13 shows an example of a determination flow. 1 is an example embodiment of a system of the present disclosure. 1 is an example embodiment of a system of the present disclosure.

Below, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These implementation examples are merely illustrative, and the present disclosure can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Note that components with the same reference numerals in this specification and drawings are mutually identical.

(First embodiment)
1 shows an example of a system configuration of this embodiment. The system of this embodiment includes a speaker 91, a microphone 92, a determination device 93, and a display device 95. The speaker 91 is a device that continuously or periodically outputs sound waves that can propagate through the pipeline 82. The microphone 92 is a device that detects sound waves from the pipeline 82. The determination device 93 is a device that determines the continuity of the pipeline 82 based on a detection signal from the microphone 92. The display device 95 is a device that displays the determination result of the determination device 93. The display device 95 may be provided in the determination device 93.

FIG. 2 shows an example of a work flow on site.
S11: A speaker 91 and a microphone 92 are installed in manholes 81-1 and 81-2 located at both ends of a pipeline 82.
S12: The speaker 91 outputs sound waves toward the pipe 82.
S13: The microphone 92 detects the sound waves from the pipe 82. As a result, the microphone 92 detects the sound waves that have passed through the pipe 82.
S 14 : The determination device 93 determines the continuity of the pipe 82 based on the detection signal detected by the microphone 92 .
S15: If there is no continuity (non-continuity in S14), the determination device 93 outputs a message indicating that there is no continuity to the display device 95. This allows the worker to visually confirm that a response to the non-continuity, such as repair or cleaning, is required.
S16: If there is continuity (continuity in S14), the determination device 93 outputs a message indicating that there is continuity to the display device 95. This allows the worker to visually confirm that the cable can be laid.

In this embodiment, in step S11, as shown in FIG. 1, an example is shown in which a speaker 91 is installed in manhole 81-1 and a microphone 92 is installed in manhole 81-2. Thus, in this embodiment, in step S11, the speaker 91 and the microphone 92 are installed at both ends of the pipeline 82. Therefore, in step S12, the speaker 91 outputs sound waves that can propagate the entire length of the pipeline 82. Then, in step S13, the microphone 92 receives the sound waves after they have propagated the entire length of the pipeline 82.

In the determination method of the present disclosure, the speaker 91 executes step S12, the microphone 92 executes step S13, and the determination device 93 executes step S14. Here, the determination in step S14 can be made by any method capable of determining the continuity state of sound waves in the pipeline 82. For example, the determination device 93 determines that there is continuity when the volume detected by the microphone 92 is greater than noise, and determines that there is no continuity when the volume is equal to or less than noise.

Furthermore, the loss of the sound waves propagating within the pipe 82 can be found using arithmetic processing. For example, a threshold value can be determined using arithmetic processing, and this can be used to determine continuity. In this case, the determination device 93 determines that there is continuity if the volume detected by the microphone 92 is greater than the threshold value, and determines that there is no continuity if the volume detected by the microphone 92 is equal to or less than the threshold value. Examples of arithmetic processing for finding the threshold value include simulation and calculation of free space propagation loss. In this case, a propagation loss model within the waveguide that also takes into account attenuation due to corrosion can be used, and noise can also be taken into account.

In this way, in this embodiment, since the determination is based on the conduction state of the sound waves propagating through the duct 82, sound waves of any frequency can be used. For example, the frequency of the sound waves may be a single frequency or may include multiple frequencies. Also, the frequency may be discrete frequencies in a predetermined band, or may be a continuous frequency.

The volume used in step S14 may be measured by the microphone 92 or by the determination device 93. When measuring the volume, averaging or statistical processing may be performed.

Furthermore, the determination device 93 may be a separate device from the microphone 92, or may be the same device. If they are separate devices, the output from the microphone 92 to the determination device 93 may be made using a wireless connection such as radio waves, or may be made using a wired connection.

As described above, in this embodiment, continuity determination is performed using sound waves, making it possible to confirm that the conduit 82 between manholes 81-1 and 81-2 is continuum without inserting a pipe camera into the conduit 82.

Second Embodiment
An example of the system configuration of this embodiment is shown in Fig. 3. In this embodiment, in step S11, a speaker 91 and a microphone 92 are both installed in a manhole 81-1 located at one end of a pipeline 82.

In this manner, in this embodiment, in step S11, both the speaker 91 and the microphone 92 are installed at one end of the pipeline 82. Therefore, in step S12, the speaker 91 outputs sound waves that can travel back and forth through the pipeline 82. Then, in step S13, the microphone 92 detects the sound waves reflected within the pipeline 82.

Here, the judgment in step S14 can be made by any method capable of judging the reflection state of sound waves in the pipe 82. For example, if the volume is greater than the noise, it is judged as non-conductive, and if the volume is equal to or less than the noise, it is judged as conductive. Instead of noise, a threshold value or the like may be used as in the first embodiment.

An obstacle 70 is present at the position where the sound waves are reflected in the duct 82. The time from when the speaker 91 outputs the sound waves until the sound waves are reflected by the obstacle 70 corresponds to the distance from the speaker 91 and microphone 92 to the obstacle 70. Therefore, by adopting this embodiment, the position where the obstacle 70 exists can be identified.

If an obstacle 70 is present in the conduit 82, it is necessary to remove the obstacle 70 and clean it before laying the optical fiber cable in the conduit 82. This embodiment can identify the location of such an obstacle 70, so cleaning can be carried out quickly. Furthermore, even when repairing the conduit 82, it is possible to identify again the places where road excavation is required, reducing unnecessary excavation.

The speaker 91, microphone 92, determination device 93, and display device 95 may be separate devices, or may be the same device.

Third Embodiment
An example of a system configuration of this embodiment is shown in Fig. 1. In this embodiment, sound waves of a plurality of different frequencies are used as the sound waves in the first embodiment. The plurality of frequencies include a first frequency and a second frequency that are predetermined, and the first frequency is higher than the second frequency.

The speaker 91 is a device capable of outputting sound waves of multiple frequencies. The microphone 92 is a device capable of detecting sound waves of multiple frequencies.

In this embodiment, in step S12, the speaker 91 outputs sound waves of multiple frequencies, and in step S13, the microphone 92 detects the sound waves of multiple frequencies. In step S14, the determination device 93 determines continuity based on the multiple frequencies.

The continuity determination in step S14 is performed, for example, in the following order.
Step S21: If the volume is greater than noise at all frequencies, it is determined that there is continuity.
Step S22: If the volume is greater than noise at frequencies equal to or greater than a first frequency and is equal to or less than noise at frequencies less than the first frequency, it is determined that there is continuity.
Step S23: If the volume is greater than noise at frequencies equal to or greater than the second frequency and is equal to or less than noise at frequencies less than the second frequency, it is determined that there is no continuity.
Step S24: If the volume is equal to or less than noise at all frequencies, it is determined that there is no continuity.

Here, the first frequency and the second frequency are set to values that depend on the diameter of the pipeline 82 and the size of the gap within the pipeline 82. By setting the first frequency and the second frequency, the determination device 93 can determine the size of the gap within the pipeline 82.

In addition, by checking the continuity in step S14 from high frequencies, it is possible to quickly confirm that continuity exists.

In addition, the first frequency and the second frequency may be values that depend on noise, instead of or in addition to the values that depend on the diameter of the pipe 82 and the size of the gap within the pipe 82.

In addition, the present disclosure is not limited to steps S21 to S24, and the continuity/non-continuity index may be calculated by weighting according to frequency and adding up the volume at all frequencies.

As described above, in this embodiment, the determination device 93 can determine the size of the gap inside the pipeline 82. Therefore, it can determine whether or not the inside of the pipeline 82 needs to be cleaned.

(Fourth embodiment)
An example of the system configuration of this embodiment is shown in Fig. 4. In this embodiment, a plurality of pipes 82-1 to 82-N are connected in parallel between manholes 81-1 and 81-2.

Figure 5 shows an example of the judgment flow. In this embodiment, steps S11 to S13 are repeatedly executed for each pipeline 82. Then, when steps S11 to S13 are completed for all pipelines 82, step S14 is executed. In step S14, the judgment device 93 judges the pipeline 82 with the highest conductivity. Here, the pipeline 82 with the highest conductivity is, for example, the pipeline 82 with the loudest volume, or the pipeline 82 whose volume is farthest from noise or a threshold value.

As described above, in this embodiment, it is possible to determine the conduit 82 with the highest conductivity. This makes it possible to identify on-site the conduit 82 in which cable installation work is easy.

Fifth Embodiment
An example of the system configuration of this embodiment is shown in Fig. 6. In this embodiment, a speaker 91 is disposed on the ground outside a manhole 81-1.

The sound waves output from the speaker 91 are repeatedly reflected and propagate through the pipe 82. Therefore, by detecting the sound waves with the microphone 92, the same action and effect as in the first embodiment can be obtained.

In this embodiment, there is no need to install the speaker 91 inside the manhole 81-1 in step S11, which simplifies the work in step S11.

Instead of using the speaker 91, as shown in FIG. 7, sound waves may be generated in the manhole 81-1 by, for example, hitting the lid 83 of the manhole 81-1 with a hammer 94. Also, instead of using the speaker 91, the sound generated when a vehicle passes over the lid 83 of the manhole 81-1 may be used.

In this embodiment, an example is shown in which only the speaker 91 is placed on the ground outside the manhole 81-1, but in step S11, the microphone 92 may also be placed on the ground outside the manhole 81-1.

Other Embodiments
The determination device 93 of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided through a network. The program of the present disclosure is a program for causing a computer to realize each function of the determination device 93 according to the present disclosure, and is a program for causing a computer to execute each procedure of the method executed by the determination device 93 according to the present disclosure. In addition, the configuration aspects of the third to fifth embodiments may be adopted in the second embodiment.

81-1, 81-2: Manhole 82: Pipe 83: Lid 91: Speaker 92: Microphone 93: Determining device 94: Hammer 95: Display device

Claims (7)

A speaker that outputs a sound wave that can propagate through the pipe;
a microphone for detecting the sound waves from the pipe;
a determination device that determines continuity of the pipeline based on a detection result by the microphone;
A system comprising: The determination device determines the continuity of the pipe based on the volume detected by the microphone.
The system of claim 1 . The speaker and the microphone are installed at both ends of the pipe,
The speaker outputs a sound wave capable of propagating along the entire length of the pipe,
The microphone detects sound waves after propagation through the entire length of the conduit.
The system of claim 1 . The determination device determines continuity when the volume detected by the microphone is greater than a predetermined threshold, and determines non-conduction when the volume detected by the microphone is equal to or less than the threshold.
The system of claim 3. The speaker and the microphone are installed at one end of the pipe,
The speaker outputs a sound wave that can travel back and forth through the pipe,
The microphone detects sound waves reflected by an obstacle in the pipeline.
The system of claim 1 . The determination device determines continuity when the volume detected by the microphone is smaller than a predetermined threshold, and determines non-conduction when the volume detected by the microphone is equal to or greater than the threshold.
The system of claim 5. A step of outputting a sound wave capable of propagating through a pipe by a speaker;
a microphone detecting the sound waves from the conduit;
A procedure in which a determination device determines continuity of the pipeline based on a detection result by the microphone;
A method for providing the above.

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