JP2008051776A - Apparatus and method for detecting water leakage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect the leakage location of a water pipe or the like buried under the ground. <P>SOLUTION: A water leakage detector 10 includes vibration detectors 20A and 20B, provided at both end positions A and B of a section to be inspected of a pipe 5, a common frequency component extracting part 34 for extracting the signal of pipe vibration having a frequency component common to that of underwater sound as a common frequency component signal for each of the detectors 20A and 20B, a correlation processing part 35 for mutual correlation-processing of the common frequency component signals of the respective vibration detecting means 20A and 20B, a leakage sensing part 36 for sensing the leakage of the pipe 5, based on the results of the correlation processing, a time difference calculating part 37 for calculating the difference Δτ in the propagation time of the common frequency component signals, corresponding to the respective detectors 20A and 20B, and a leakage position calculating part 38 for detecting the position P of the leakage on the pipe 5, based on the difference Δτ in the propagation time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water leakage detection device that detects a water leakage position of a water pipe or the like buried in the ground with high accuracy.

  Conventionally, water leakage in water pipes (hereinafter also referred to as pipes) buried in the ground has been regarded as a problem. In particular, in urban areas, vibrations caused by automobiles, trains, etc. make cemented pipes fragile and water leakage tends to occur. Under such circumstances, a method for detecting a water leakage position in piping or the like has been studied.

  One of the methods for detecting the position of water leakage in piping and the like is a method in which an investigator confirms vibration by ear. In this method, the investigator listens to the water leak sound from the surface and identifies the position where the water leak sound is best heard. Then, dig the place and check the piping etc. to see if there is any water leakage.

  However, in this method, since the investigator examines vibrations of the pipes or the like with his / her ears, skilled skills are required to detect the water leakage position with high accuracy.

As another method, there is a method of obtaining a leak position by simultaneously capturing vibration signals on the pipe at two positions exposed from the ground surface such as a valve of the pipe and performing a cross-correlation process. Specifically, vibration signals detected at two locations are subjected to cross-correlation processing to determine a difference in propagation time. And a water leak position is calculated from the difference of the propagation time, the distance of the detected position of two places, and the propagation speed of the vibration which propagates piping (for example, refer to patent documents 1).
JP-A-11-201859

  However, in the conventional water leakage detection method, when noise vibration other than vibration due to water leakage is applied to a pipe or the like, it is difficult to determine whether or not the peak value of the waveform subjected to cross-correlation processing is caused by water leakage. Therefore, there is a problem that the detection accuracy of the water leakage position is not necessarily high.

  This invention is made | formed in view of the said situation, and it aims at providing the water leak detection apparatus which detects the water leak position of water pipes etc. which were embed | buried under the ground with high precision.

  The present invention takes the following means in order to solve the above problems.

  The invention corresponding to claim 1 is a water leakage detection device for detecting a water leakage position of a water pipe buried in the ground, comprising an underwater microphone and a vibration sensor installed at both ends of the inspection section of the water pipe. A plurality of vibration detecting means, and means for generating a common frequency component signal having a common frequency component of the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensor for each of the vibration detecting means. Correlation processing means for cross-correlating common frequency component signals of the vibration detection means, water leakage detection means for detecting water leakage in the water pipe based on the result of the cross-correlation processing, and water leakage detection means When it is detected that water leakage has occurred, time difference calculating means for obtaining a difference in propagation time of the common frequency component signal corresponding to each vibration detecting means, and the time difference calculating means Based on the difference between the calculated propagation times Ri is a leak detector and means for detecting the water leakage position of the water pipe.

  The invention corresponding to claim 2 is a water leakage detection device for detecting a water leakage position of a water pipe buried in the ground, the underwater microphone installed at one place in the inspection section of the water pipe, and the inspection A first correlation function is calculated by cross-correlating the plurality of vibration sensors installed at both ends of the section, the underwater sound detected by the underwater microphone, and the pipe vibration detected by each vibration sensor, respectively. Based on the result of the cross-correlation processing by the correlation processing means, the second correlation processing means for cross-correlating the first correlation function corresponding to each vibration sensor, and the second correlation processing means, A water leak detecting means for detecting and a time difference calculating means for obtaining a time difference when the first correlation function corresponding to each vibration sensor has a maximum value when it is detected by the water leak detecting means. If, based on the time difference calculated by the time difference calculating means, a leakage detector and means for detecting the water leakage position of the water pipe.

  The invention corresponding to claim 3 is a water leakage detection device for detecting a water leakage position of a water pipe buried in the ground, and a plurality of underwater microphones installed at both ends of an inspection section of the water pipe, and the inspection A third correlation function is calculated by cross-correlating the vibration sensor installed at one location in the section, the underwater sound detected by each of the underwater microphones and the pipe vibration detected by the vibration sensor, respectively. Based on the results of the cross-correlation processing by the correlation processing means, the fourth correlation processing means for cross-correlating the third correlation function corresponding to each vibration sensor, and the fourth correlation processing means, A time difference calculation for obtaining a time difference when the third correlation function corresponding to each vibration sensor has a maximum value when water leakage is detected by the water leakage detection means for detecting and the water leakage detection means. And stage, based on the time difference calculated by the time difference calculating means, a leakage detector and means for detecting the water leakage position of the water pipe.

  The invention corresponding to claim 4 includes an underwater microphone installed in a water pipe buried in the ground, a vibration sensor installed at the same location as the installation location of the underwater microphone, and an underwater detected by the underwater microphone. Correlation processing means for performing cross-correlation processing between sound and pipe vibration detected by the vibration sensor, and water leakage position detection means for detecting a water leakage position of the water pipe based on the result of the cross-correlation processing. This is a leak detection device.

  According to a fifth aspect of the present invention, there is provided the water leakage detection device according to the fourth aspect, wherein the water leakage position detection means includes a water leakage detection means for detecting water leakage in the water pipe and water leakage caused by the water leakage detection means. When a difference is detected, a time difference calculating means for obtaining a difference in propagation time between the underwater sound and the pipe vibration, and a water leak position of the water pipe based on the difference in propagation time calculated by the time difference calculating means. And a means for detecting water leakage.

  The invention corresponding to claim 6 is the water leakage detection device corresponding to any one of claims 1 to 5, wherein the low-pass filter processing is performed on the waveform of the cross-correlation function obtained by the correlation processing means. Is a water leakage detection device.

  The invention corresponding to claim 7 is the water leakage detection device corresponding to any one of claims 1 to 6, which is preset with respect to the value of the cross-correlation function obtained by the correlation processing means. It is a water leak detection apparatus provided with the means to output the value more than a value.

  In the invention corresponding to claim 8, the data of the underwater sound and the pipe vibration are obtained from a plurality of vibration detecting means having an underwater microphone and a vibration sensor installed at both ends of the inspection section of the water pipe buried in the ground. A data collection step for collecting, a step of generating a common frequency component signal having a common frequency component of underwater sound detected by the underwater microphone and pipe vibration detected by the vibration sensor for each of the vibration detecting means, A correlation processing step for cross-correlating the common frequency component signal of each vibration detection means, a water leakage detection step for detecting water leakage in the water pipe based on the result of the cross-correlation processing, and water leakage by the water leakage detection step A time difference calculating step for obtaining a difference in propagation time of the common frequency component signal corresponding to each vibration detecting means, Based on the difference in propagation time calculated by the time difference calculating step, a water leakage detection method comprising the steps of detecting a water leakage position of the water pipe.

  The invention corresponding to claim 9 is a step of collecting underwater sound data from an underwater microphone installed at one place in an inspection section of a water pipe buried in the ground, and installed at both ends of the inspection section. Collecting pipe vibration data from a plurality of vibration sensors, cross-correlating the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensors, respectively, to calculate a first correlation function Based on the results of the first correlation processing step, the second correlation processing step for cross-correlating the first correlation function corresponding to each vibration sensor, and the cross-correlation processing by the second correlation processing step, When a water leakage detection step for detecting water leakage and the occurrence of water leakage are detected by the water leakage detection step, the first correlation function corresponding to each vibration sensor has a maximum value. A time difference calculating step of obtaining a time difference between the time that, based on the time difference calculated by the time difference calculating step, a water leakage detection method comprising the steps of detecting a water leakage position of the water pipe.

  The invention corresponding to claim 10 is a step of collecting underwater sound data from a plurality of underwater microphones installed at both ends of an inspection section of a water pipe buried in the ground, and is installed at one place in the inspection section Collecting a pipe vibration data from the vibration sensor, a cross-correlation process between the underwater sound detected by each underwater microphone and the pipe vibration detected by the vibration sensor to calculate a third correlation function. Based on the results of the third correlation processing step, the fourth correlation processing step for cross-correlating the third correlation function corresponding to each vibration sensor, and the cross-correlation processing by the fourth correlation processing step, When a water leakage detection step for detecting water leakage and the occurrence of water leakage is detected by the water leakage detection step, a third correlation function corresponding to each vibration sensor is A time difference calculating step of obtaining the time difference when having a large value, based on the time difference calculated by the time difference calculating step, a water leakage detection method comprising the steps of detecting a water leakage position of the water pipe.

  The invention corresponding to claim 11 includes a step of collecting underwater sound data from an underwater microphone installed in a water pipe buried in the ground, and a vibration sensor installed at the same location as the installation location of the underwater microphone. A result of cross-correlation processing by the step of collecting pipe vibration data, a correlation processing step of cross-correlating the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensor, and the correlation processing step And a step of detecting a water leak position of the water pipe based on the method.

  The present invention may be expressed as “device” or “program” for each device, and may be expressed as “method” for each system or device. That is, the present invention can be expressed in any category.

<Action>
Therefore, the present invention has the following effects by taking the above-described means.

  The invention corresponding to claims 1 and 8 includes a plurality of vibration detecting means having an underwater microphone and a vibration sensor installed at both ends of an inspection section of a water pipe buried in the ground, underwater sound, and pipe vibration. Generating a common frequency component signal for each vibration detecting means, a correlation processing means for cross-correlating the common frequency component signal of each vibration detecting means, and a water pipe leak position based on the result of the cross-correlation processing Because it is possible to perform cross-correlation processing after obtaining the common frequency component of underwater sound and pipe vibration by the configuration equipped with the means for detecting, the position of water leakage in water pipes buried underground is highly accurate Can be detected.

  The invention corresponding to claims 2 and 9 includes an underwater microphone installed at one place in an inspection section of a water pipe buried in the ground, a plurality of vibration sensors installed at both ends of the inspection section, and underwater sound. First correlation processing means for calculating a first correlation function by cross-correlating the pipe vibration and the pipe vibration, a second correlation processing means for cross-correlating the first correlation function corresponding to each vibration sensor, and a second correlation Based on the result of the cross-correlation processing by the processing means, the configuration including the means for detecting the water leakage position of the water pipe cross-correlates the underwater sound and the pipe vibration. Can be detected with high accuracy.

  The invention corresponding to claims 3 and 10 includes a plurality of underwater microphones installed at both ends of the inspection section buried in the ground, a vibration sensor installed at one place in the inspection section, and each underwater microphone. A third correlation processing means for calculating a third correlation function by cross-correlating the detected underwater sound and pipe vibration detected by the vibration sensor, and a cross-correlation processing for the third correlation function corresponding to each vibration sensor The correlation between the pipe vibration and the underwater sound is provided by a configuration comprising a fourth correlation processing means for detecting the leakage position of the water pipe based on the result of the cross-correlation processing by the fourth correlation processing means. Since it is processed, it is possible to detect the leakage position of water pipes and the like with high accuracy.

  The invention corresponding to claims 4 and 11 includes an underwater microphone installed in a water pipe buried in the ground, a vibration sensor installed at the same location as the installation location of the underwater microphone, an underwater sound and pipe vibration. Cross-correlation processing is performed between underwater sound and pipe vibration with a configuration that includes correlation processing means for cross-correlation processing and water leakage position detection means for detecting the water leakage position of water pipes based on the results of the cross-correlation processing. Therefore, it is possible to detect the water leakage position in piping buried in the ground with high accuracy. Moreover, since the water leak detection apparatus calculates | requires a water leak position from the signal of the vibration by the underwater microphone and vibration sensor which were installed in one place of water supply piping, it can obtain | require a water leak position easily.

The invention corresponding to claim 5 is the water leakage detection device corresponding to claim 4, wherein the water leakage position detection means is a water leakage detection means for detecting water leakage in the water pipe, and the case where the occurrence of water leakage is detected. A time difference calculating means for obtaining a difference in propagation time between the underwater sound and the pipe vibration, and a means for detecting a leakage position of the water pipe based on the difference in propagation time calculated by the time difference calculating means. Therefore, the water leakage position can be obtained from the cross-correlation function between the underwater sound and the pipe vibration.

The invention corresponding to claim 6 is the water leakage detection device corresponding to any one of claims 1 to 5, comprising means for low-pass filtering the waveform of the cross-correlation function obtained by the correlation processing means. Therefore, the noise component can be removed from the cross correlation function.

  The invention corresponding to claim 7 is the water leakage detection device corresponding to any one of claims 1 to 6, wherein the value of the cross-correlation function obtained by the correlation processing means is not less than a preset value. Since a means for outputting a value is provided, the peak value of the waveform of the cross correlation function can be easily determined.

  According to the present invention, it is possible to detect a water leakage position such as a water pipe buried in the ground with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic diagram showing a configuration of a water leakage detection device 10 according to the first embodiment of the present invention.

  The water leakage detection device 10 includes a vibration detection device 20 and a data processing device 30.

  The vibration detection device 20 includes an underwater microphone 21 and a vibration sensor 22, and is installed in a fire hydrant or the like provided on the pipe 5 at regular intervals.

  The underwater microphone 21 is attached in the pipe 5 and detects underwater sound. The underwater microphone 21 also sends “underwater sound data” indicating the detected underwater sound to the underwater sound data collection unit 31.

  The vibration sensor 22 is attached to the pipe 5 and detects pipe vibration of the pipe 5. Further, the vibration sensor 22 sends “pipe vibration data” indicating the detected pipe vibration to the pipe vibration data collection unit 32.

  In the present embodiment, for convenience, subscripts A and B are added to those corresponding to position A and position B. For example, when water leaks in the pipe 5, the vibration detection devices installed at the positions A and B that sandwich the water leak position P are denoted as 20A and 20B, respectively.

  The data processing device 30 includes an underwater sound data collection unit 31, a pipe vibration data collection unit 32, a common frequency component analysis unit 33, a common frequency component extraction unit 34, a correlation processing unit 35, a water leak detection unit 36, a time difference calculation unit 37, and a water leak. A position calculation unit 38 and a storage unit 39 are provided, and a water leak position P of the pipe 5 is detected based on a signal detected by the vibration detection device 20.

  The underwater sound data collection unit 31 collects the underwater sound data detected by the underwater microphone 21. The underwater sound data collection unit 31 sends the collected underwater sound data to the common frequency component analysis unit 33.

  The pipe vibration data collection unit 32 collects pipe vibration data detected by the vibration sensor 22. Further, the pipe vibration data collection unit 32 sends the collected pipe vibration data to the common frequency component analysis unit 33.

  Based on the underwater sound data sent from the underwater sound data collection unit 31 and the pipe vibration data sent from the pipe vibration data collection unit 32, the common frequency component analysis unit 33 uses the common frequency component of the underwater sound and the pipe vibration. (Cross spectrum) is obtained. Further, the common frequency component analysis unit 33 sends the common frequency component data to the common frequency component extraction unit 34.

  When receiving the common frequency component data from the common frequency component analyzing unit 33, the common frequency component extracting unit 34 generates a “common frequency component signal Y (t)” using the common frequency component as a filter coefficient. Specifically, a pipe vibration signal having a frequency component common to the underwater sound is extracted as a common frequency component signal. Further, the common frequency component extraction unit 34 sends the data of the common frequency component signal Y (t) to the correlation processing unit 35.

  The correlation processing unit 35 performs cross-correlation processing on the common frequency component signals of the vibration detection devices installed at both ends of the inspection sections that are sequentially selected in the batch processing.

Specifically, when the section of position A and position B is selected as the inspection section, the correlation processing unit 35 outputs the common frequency component signal Y _A (t) at the position A and the common frequency component signal at the position B as Y. _{From B} (t), a cross-correlation function Φ _AB (τ) is obtained by the following equation (1).

Further, the correlation processing unit 35 sends the data of the cross correlation function Φ _AB (τ) to the water leakage detection unit 36.

The water leakage detection unit 36 detects water leakage in the pipe 5 based on the data of the cross-correlation function Φ _AB (τ) sent from the correlation processing unit 35. Specifically, if the cross-correlation function Φ _AB (τ) corresponding to the inspection section between the position A and the position B is equal to or larger than a preset set value T, it is determined that water leakage has occurred in the inspection section. If it is smaller than the set value T, it is determined that no water leakage has occurred. Then, the water leakage detection unit 36 sends these determination results to the time difference calculation unit 37.

The time difference calculation unit 37 obtains the time difference Δτ when the cross-correlation function Φ _AB (τ) has the maximum value when the water leakage detection unit 36 detects that water leakage has occurred.

That is, when water leakage occurs, the common frequency component signals Y _A (t) and Y _B (t) corresponding to the vibration detection devices 20A and 20B installed at the positions A and B sandwiching the water leakage position P are inserted. ) Have waveforms having peak values as shown in FIGS. 2A and 2B, respectively. These waveforms arrive after a propagation time depending on the distance between the water leakage position P and the positions A and B. Therefore, when the cross-correlation processing is performed on the common frequency component signals Y _A (t) and Y _B (t) of the vibration detection devices 20A and 20B, the cross-correlation function Φ _AB ( τ) is obtained (see FIG. 2C). Therefore, the time difference calculation unit 37 can obtain the time difference Δτ between the common frequency component signals Y _A (t) and Y _B (t) by obtaining the peak value of the cross-correlation function Φ _AB (τ).

The water leakage position calculation unit 38 obtains the water leakage position P when the water leakage detection unit 36 detects that water leakage has occurred in the inspection section. Specifically, when it is detected that water leakage has occurred in the inspection section between the position A and the position B, the value of the distance L _AB between the position A and the position B and the value of the propagation speed Ck of the pipe vibration Are read from the storage unit 39. Then, the value of the time difference Δτ calculated by the time difference calculation unit 37 is substituted into the following equation (2) to calculate the distance l _A from the position A where the vibration detection device 20A is installed to the water leakage position P.

l _A = (L _AB −Ck · Δτ) / 2 (2)
Further, the water leakage position calculation unit 38 outputs the position information of the water leakage position P from the information of the distance l _A to an external output device or the like.

The storage unit 39 stores data such as the value of the distance L _AB between the position A and the position B, the value of the propagation speed Ck of the piping vibration, and the piping diagram.

  Next, operation | movement of the water leak detection apparatus 10 which concerns on this embodiment is demonstrated using the flowchart of FIG.

  As a premise, it is assumed that the position P where water leakage is estimated is selected in advance. Thereby, the water tap etc. which exist in the position A-N of the vicinity of the position P are selected as a test object.

  Under such a premise, underwater sound data and pipe vibration data are collected by the underwater sound data collection unit 31 and the pipe vibration data collection unit 32 at each position A to N (step S1).

When the underwater sound data and the pipe vibration data are collected, the common frequency component analysis unit 33 analyzes the common frequency component at each position A to N of the underwater sound and the pipe vibration. Further, common frequency component signals Y _A (t) to Y _N (t) at the respective positions _{A to N} are generated by the common frequency component extraction unit 34 using the filter coefficients (step S2). At this time, the magnitude of the amplitude is normalized.

  Subsequently, the correlation processing unit 35 sequentially performs cross-correlation processing on the common frequency component signals between the two points set as the examination section among the positions A to N (step S3). For example, in FIG. 4, the common frequency component signal at each of the position A and the positions B to E is subjected to cross-correlation processing.

Next, the water leakage detection unit 36 determines whether or not the value of the cross-correlation function Φ _AB (τ) obtained by the cross-correlation process is larger than the set value T. As a result of the determination, if the cross-correlation function has a value (peak value) greater than the set value T, it is determined that water leakage has occurred (steps S4-Yes, S5). For example, in FIG. 4, the cross-correlation function Φ _AB (τ) of the common frequency component signal at the position A and the position B has a peak value, and water leakage has occurred between the position A and the position B. Detected.

When it is detected that water leakage has occurred, the difference Δτ in propagation time between the common frequency component signals Y _A (t) and Y _B (t) is calculated by the time difference calculation unit 37 (step S6).

Subsequently, the water leakage position P is calculated by the water leakage position calculation unit 38 (step S7). Specifically, among the positions A to N, a distance l _A from the position A set as the reference position to the water leakage position P is calculated. Then, based on the distance l _A , position information and the like of the water leakage position P on the piping diagram is output to the outside. Thereby, a water leak detection process is complete | finished.

On the other hand, if the value of the cross-correlation function Φ _AB (τ) by the cross-correlation process is smaller than the set value T in step S4, it is determined that no water leakage has occurred. Thereby, a water leak detection process is complete | finished (step S4-No, S8).

  As described above, the water leakage detection device 10 according to the present embodiment has the vibration detection devices 20A and 20B installed at the positions A and B at both ends of the inspection section of the pipe 5, and the vibration detection devices 20A and 20B. A common frequency component extraction unit 34 that extracts a pipe vibration signal having a frequency component common to the underwater sound as a common frequency component signal, and a correlation processing unit 35 that cross-correlates the common frequency component signals of the vibration detection units 20A and 20B. Based on the result of the cross-correlation processing, the time difference calculation for obtaining the difference Δτ of the propagation time of the water leakage detection unit 36 for detecting the water leakage of the pipe 5 and the common frequency component signal corresponding to each of the vibration detection devices 20A and 20B. Unit 37 and a water leak position calculation unit 38 for detecting the water leak position P of the pipe 5 based on the propagation time difference Δτ, and a common frequency component signal of underwater sound and pipe vibration Since the cross-correlation process from seeking (t), it can detect the water leakage position P in the pipe 5 or the like which is embedded in the ground with high accuracy.

  That is, since the common frequency component signal of both the underwater sound and the pipe vibration at the position A is obtained, and the cross-correlation process and the result of the cross-correlation process at the position B are further performed, the influence on noise can be reduced. The detection accuracy of the water leakage position P can be improved. Thereby, the breakage position of the pipe 5 in which water leakage has occurred can be identified and promptly treated, which contributes to protecting social assets such as water resources.

  Needless to say, the same argument holds even if the common frequency component extraction unit 34 extracts an underwater sound signal having a frequency component common to the pipe vibration as the common frequency component signal.

<Second Embodiment>
FIG. 5 is a schematic diagram showing the configuration of the water leakage detection device 10 according to the second embodiment of the present invention. Note that the same parts as those already described are denoted by substantially the same reference numerals, and redundant description is omitted. In addition, the following description is also omitted in the following embodiments.

  In the present embodiment, a first correlation processing unit 40 and a second correlation processing unit 41 are provided instead of the common frequency component analysis unit 33, the common frequency component extraction unit 34, and the correlation processing unit 35 in the first embodiment.

  The first correlation processing unit 40 uses the underwater sound detected by the underwater microphone 21A attached to one position of the pipe 5 as a reference, and mutually interacts with each of the pipe vibrations detected by the plurality of vibration sensors 22A and 22B. Correlation processing is performed. Thereby, it is possible to extract only the pipe vibration signal correlated with the underwater sound.

Specifically, the underwater sound of the underwater microphone 21 is W _A (t), and the pipe vibrations of the two vibration sensors 22A and 22B are K _A (t) and K _B (t). 4) The cross correlation functions φ _AA (τ) and φ _AB (τ) are obtained.

The second correlation processing unit 41 further performs cross-correlation processing on the two cross-correlation functions φ _AA (τ) · φ _AB (τ) obtained by the first correlation processing unit 40. That is, the second correlation processing unit 41 calculates the cross-correlation function Φ _AB (τ) from the cross-correlation functions φ _AA (τ) · φ _AB (τ) corresponding to the pipe vibration of the vibration sensors 22A and 22B based on the following equation (5). τ) is obtained.

As described above, the water leakage detection apparatus 10 according to the present embodiment includes the underwater microphone 21A installed at one place of the pipe 5, the plurality of vibration sensors 22A and 22B installed at a plurality of positions of the pipe 5, and the underwater _A first correlation processing unit 40 that performs cross-correlation processing between the underwater sound W _A (t) detected by the microphone 21A and the pipe vibrations K _A (t), K _B (t) detected by the vibration sensors 22A and 22B. And a second correlation processing unit 41 that further performs cross-correlation processing on the cross-correlation functions φ _AA (τ) and φ _AB (τ) obtained by the first correlation processing unit 40. Since the cross correlation processing is performed, the water leakage position P of the pipe 5 can be detected with high accuracy.

  That is, after performing the cross-correlation process using both the underwater sound and the pipe vibration at the position A, and further performing the cross-correlation process with the result of the cross-correlation process at the position B, the influence on noise can be reduced. It is possible to improve the detection accuracy of the water leakage position P.

  As shown in FIG. 6, the underwater sound detected by the underwater microphones 21A and 21B attached to a plurality of locations on the basis of the piping vibration detected by the vibration sensor 22B attached to one location of the piping 5. The water leakage position can also be detected by performing cross-correlation processing with each other. In this case, instead of the first correlation processing unit 40 and the second correlation processing unit 41, a third correlation processing unit 42 and a fourth correlation processing unit 43 are provided, and only the underwater sound signal correlated with the pipe vibration is extracted. Then, the peak value of the cross correlation function is detected.

  In other words, a plurality of underwater microphones 21A and 21B installed at a plurality of positions, a vibration sensor 22B installed at one location, and underwater sound detected by each of the underwater microphones 21A and 21B and piping detected by the vibration sensor 22B By providing a third correlation processing unit 42 that performs cross-correlation processing with vibrations, and a fourth correlation processing unit 43 that further performs cross-correlation processing on the cross-correlation function obtained by the third correlation processing unit 42, piping vibration and underwater Since the sound and the cross correlation process are performed, the water leakage position P of the pipe 5 can be detected with high accuracy.

<Third Embodiment>
FIG. 7 is a schematic diagram showing the configuration of the water leakage detection device 10 according to the third embodiment of the present invention.

  In the present embodiment, the water leakage position P is obtained based on signals detected at one place, not signals detected at a plurality of places of the pipe 5.

  The correlation processing unit 35 performs a cross-correlation process between the underwater sound detected by the underwater microphone 21 and the vibration sensor 22 installed at the same position of the pipe 5 and the pipe vibration.

For example, assuming that the underwater sound detected by the underwater microphone 21 is W (t) and the pipe vibration detected by the vibration sensor 22 is K (t), the cross-correlation function Φ (τ) is obtained by the following equation (6).

  The water leakage detection unit 36 detects water leakage in the pipe 5 based on the cross-correlation function Φ (τ) obtained by the correlation processing unit 35. Specifically, when the cross-correlation function Φ (τ) corresponding to the inspection section between the position A and the position B has a value that is equal to or greater than a preset setting value T, water leaks in the inspection section. If it is smaller than the set value T, it is determined that no water leakage has occurred. Then, the water leakage detection unit 36 sends these determination results to the time difference calculation unit 37.

  The time difference calculation unit 37 obtains a time difference Δτ when the cross-correlation function Φ (τ) has a maximum value when the water leakage detection unit 36 detects that water leakage has occurred. Further, the time difference calculation unit 37 sends the obtained time difference Δτ to the water leakage position calculation unit 38.

The water leakage position calculation unit 38 obtains the water leakage position P when the water leakage detection unit 36 detects that water leakage has occurred in the inspection section. Specifically, when it is detected that water leakage has occurred in the inspection section between the position A and the position B, the value of the propagation speed Cw of the underwater sound and the value of the propagation speed Ck of the pipe vibration are stored in the storage unit. Read from 39. Then, a distance l _A from the position A where the underwater microphone 21 and the vibration sensor 22 are installed to the water leakage position P is calculated based on the following equation (6).

l _A = Δτ · (Cw−Ck) (6)
The storage unit 39 stores data such as the value of the underwater sound propagation speed Cw and the value of the pipe vibration propagation speed Ck.

  As described above, the water leakage detection device 10 according to the present embodiment includes the underwater microphone 21 installed in the pipe 5 embedded in the ground, and the vibration sensor 22 installed at the same location as the installation location of the underwater microphone 21. And a correlation processing unit 35 that performs a cross-correlation process between the underwater sound detected by the underwater microphone 21 and the pipe vibration detected by the vibration sensor 22, and the result of the cross-correlation process by the correlation processing unit 35. A water leak detection unit 36 for detecting water leak, a time difference calculation unit 37 for obtaining a propagation time difference Δτ between the underwater sound and the pipe vibration when the water leak detection unit 36 detects the occurrence of water leak, and a time difference calculation A leakage position calculation unit 38 for detecting the leakage position P of the pipe 5 based on the propagation time difference Δτ calculated by the unit 37 is provided. Place Since detecting the can detect the water leakage position in the pipe 5 which is buried in the ground with high accuracy.

  Moreover, the water leak detection apparatus 10 calculates | requires the water leak position P based on the signal detected by the vibration detection apparatus 20 installed in one place. Therefore, since it is not necessary to install the vibration detection devices 20 at a plurality of locations in the pipe 5, the water leakage position P can be easily obtained.

  That is, even if the pipe 5 does not know the distance of the inspection section between two points, the water leakage position P can be obtained.

  In addition, in the water leak detection apparatus 10 according to the present embodiment, since the vibration detection apparatus 20 is installed only in one place, it may be difficult to obtain the propagation direction of the underwater sound and the pipe vibration. Even in this case, the propagation direction can be easily obtained by examining the waveform after slightly shifting the vibration detection device 20.

  Note that, when performing the cross-correlation process by the correlation processing unit 35, a “low-pass filter process” for passing only a signal in a low frequency band may be executed. In general, the result of cross-correlation processing of detection signals by an underwater microphone or vibration sensor includes noise and the like, so it is difficult to determine the maximum value. Therefore, by performing low-pass filter processing that passes only signals in the low frequency band, it is possible to eliminate fine jagged waveforms due to noise components from the cross-correlation function, and it is possible to obtain only the original correlation processing result. Specifically, the waveform of the cross-correlation function as shown in FIG. 8A becomes a smooth waveform as shown in FIG. Thereby, when obtaining the time difference Δτ when the value of the cross-correlation function becomes the maximum value, the maximum value can be easily determined, and the water leakage position P can be detected with higher accuracy.

  Further, the correlation processing unit 35 may perform “threshold filter processing” for outputting a value equal to or greater than a preset threshold Th. Thereby, all values lower than the threshold Th are filtered. Specifically, the waveform of the cross-correlation function as shown in FIG. 8A becomes a waveform having a peak as shown in FIG. As a result, the maximum value can be easily determined, so that water leakage can be detected with higher accuracy.

<Others>
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine a component suitably in different embodiment.

It is a schematic diagram which shows the structure of the water leak detection apparatus 10 which concerns on the 1st Embodiment of this invention. It is a figure which shows the waveform of the common frequency component signal which concerns on the same embodiment, and the waveform of a cross correlation function. It is a flowchart for demonstrating operation | movement of the water leak detection apparatus 10 which concerns on the same embodiment. It is a figure which shows the concept of the test area which concerns on the embodiment. It is a schematic diagram which shows the structure of the water leak detection apparatus 10 which concerns on the 2nd Embodiment of this invention. It is a figure which shows the modification of the water leak detection apparatus 10 which concerns on the same embodiment. It is a schematic diagram which shows the structure of the water leak detection apparatus 10 which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the low-pass filter process and threshold value filter process of the water leak detection apparatus which concern on the embodiment.

Explanation of symbols

5 ... pipe, 10 ... water leakage detection device, 20 ... vibration detection device, 21 ... underwater microphone,
22 ... Vibration sensor, 30 ... Data processing device, 31 ... Underwater sound data collection unit,
32 ... Piping vibration data collection unit, 33 ... Common frequency component analysis unit,
34 ... Common frequency component extraction unit, 35 ... Correlation processing unit, 36 ... Water leakage detection unit,
37 ... time difference calculation unit, 38 ... water leakage position calculation unit, 39 ... storage unit,
40 ... 1st correlation processing part, 41 ... 2nd correlation processing part, 42 ... 3rd correlation processing part,
43: Fourth correlation processing unit.

Claims (11)

A water leakage detection device for detecting a water leakage position of a water pipe buried in the ground,
A plurality of vibration detection means installed at both ends of the inspection section of the water pipe, having an underwater microphone and a vibration sensor,
Means for generating a common frequency component signal having a common frequency component of underwater sound detected by the underwater microphone and pipe vibration detected by the vibration sensor for each of the vibration detection means;
Correlation processing means for performing cross-correlation processing on the common frequency component signal of each vibration detection means;
Based on the result of the cross-correlation process, water leakage detection means for detecting water leakage of the water pipe,
A time difference calculating means for obtaining a difference in propagation time of the common frequency component signal corresponding to each vibration detecting means when it is detected that water leakage has occurred by the water leak detecting means;
A water leak detection device comprising: means for detecting a water leak position of the water pipe based on a difference in propagation time calculated by the time difference calculation means. A leak detection device that detects the leak position of a water pipe buried in the ground,
An underwater microphone installed in one place in the inspection section of the water pipe;
A plurality of vibration sensors installed at both ends of the inspection section;
First correlation processing means for calculating a first correlation function by cross-correlating the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensors;
Second correlation processing means for cross-correlating the first correlation function corresponding to each vibration sensor;
Based on the result of cross-correlation processing by the second correlation processing means, water leakage detection means for detecting water leakage in the water pipe;
A time difference calculating means for obtaining a time difference when the first correlation function corresponding to each vibration sensor has a maximum value when it is detected by the water leakage detecting means that water leakage has occurred;
And a means for detecting a leak position of the water pipe based on the time difference calculated by the time difference calculating means. A water leakage detection device for detecting a water leakage position of a water pipe buried in the ground,
A plurality of underwater microphones installed at both ends of the inspection section of the water pipe;
A vibration sensor installed at one location in the inspection section;
Third correlation processing means for calculating a third correlation function by cross-correlating the underwater sound detected by each of the underwater microphones and the pipe vibration detected by the vibration sensor;
A fourth correlation processing means for cross-correlating the third correlation function corresponding to each vibration sensor;
Based on the result of cross-correlation processing by the fourth correlation processing means, water leakage detection means for detecting water leakage in the water pipe;
A time difference calculating means for obtaining a time difference when the third correlation function corresponding to each vibration sensor has a maximum value when it is detected by the water leakage detecting means that water leakage has occurred;
And a means for detecting a leak position of the water pipe based on the time difference calculated by the time difference calculating means. An underwater microphone installed in a water pipe buried underground,
A vibration sensor installed at the same location as the installation location of the underwater microphone;
Correlation processing means for cross-correlating the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensor;
A water leak detection device comprising: a water leak position detection means for detecting a water leak position of the water pipe based on the result of the cross correlation process. In the water leak detection device according to claim 4,
The water leakage position detecting means includes
Water leakage detection means for detecting water leakage in the water pipe;
A time difference calculating means for obtaining a difference in propagation time between the underwater sound and the pipe vibration when it is detected by the water leakage detection means;
A water leak detection device comprising: means for detecting a water leak position of the water pipe based on a difference in propagation time calculated by the time difference calculation means. The water leakage detection device according to any one of claims 1 to 5,
A water leakage detection apparatus comprising: means for performing low-pass filter processing on the waveform of the cross-correlation function obtained by the correlation processing means. The water leakage detection device according to any one of claims 1 to 6,
A water leakage detection apparatus comprising: means for outputting a value equal to or greater than a preset value with respect to the value of the cross-correlation function obtained by the correlation processing means. A data collection step for collecting data of underwater sound and pipe vibration from a plurality of vibration detecting means having an underwater microphone and a vibration sensor installed at both ends of an inspection section of a water pipe buried in the ground;
Generating a common frequency component signal having a common frequency component of the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensor for each of the vibration detection means;
A correlation processing step of cross-correlating the common frequency component signal of each vibration detecting means;
Based on the result of the cross-correlation process, a water leakage detection step for detecting water leakage in the water pipe,
When it is detected that water leakage has occurred in the water leakage detection step, a time difference calculation step for obtaining a difference in propagation time of the common frequency component signal corresponding to each vibration detection unit;
And a step of detecting a leak position of the water pipe based on a difference in propagation time calculated by the time difference calculating step. Collecting underwater sound data from an underwater microphone installed at one location in the inspection section of a water pipe buried underground;
Collecting piping vibration data from a plurality of vibration sensors installed at both ends of the inspection section;
A first correlation processing step of calculating a first correlation function by cross-correlating the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensors;
A second correlation processing step for cross-correlating the first correlation function corresponding to each vibration sensor;
Based on the result of the cross-correlation process in the second correlation process step, a water leak detection step for detecting water leak in the water pipe;
A time difference calculating step for obtaining a time difference when the first correlation function corresponding to each vibration sensor has a maximum value when it is detected that water leakage has occurred in the water leakage detecting step;
And a step of detecting a water leak position of the water pipe based on the time difference calculated by the time difference calculating step. Collecting underwater sound data from a plurality of underwater microphones installed at both ends of an inspection section of a water pipe buried underground;
Collecting pipe vibration data from a vibration sensor installed at one location in the inspection section;
A third correlation processing step of calculating a third correlation function by cross-correlating the underwater sound detected by each of the underwater microphones and the pipe vibration detected by the vibration sensor;
A fourth correlation processing step of cross-correlating a third correlation function corresponding to each vibration sensor;
Based on the result of the cross-correlation process in the fourth correlation process step, a water leak detection step for detecting water leak in the water pipe;
A time difference calculating step for obtaining a time difference when the third correlation function corresponding to each vibration sensor has a maximum value when it is detected that water leakage has occurred in the water leakage detecting step;
And a step of detecting a water leak position of the water pipe based on the time difference calculated by the time difference calculating step. Collecting underwater sound data from underwater microphones installed in underground water pipes;
Collecting pipe vibration data from a vibration sensor installed at the same location as the installation location of the underwater microphone;
A correlation processing step for cross-correlating the underwater sound detected by the underwater microphone and the pipe vibration detected by the vibration sensor;
And a step of detecting a water leak position of the water pipe based on a result of the cross-correlation processing in the correlation processing step.

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