JP2015043001A - Water leakage detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the accuracy of a water leakage determination result to surely detect the presence or absence of water leakage.SOLUTION: A water leakage detection device includes a sensor, an A/D conversion unit, a level comparison unit, a counter unit, a water leakage determination unit, and water leakage determination condition input unit. The sensor is installed in a pipeline to capture vibration and sound generated from the pipeline. The A/D conversion unit converts a signal captured by the sensor into a digital signal. The level comparison unit compares the signal level of the digital signal with a determination signal level and outputs a determination result. The counter unit includes a counter for a determination level or higher and a counter for levels lower than the determination level, which increment their count values by +1 on the basis of the determination result. The water leakage determination unit determines water leakage if a ratio of a count value of the counter for the determination level or higher to that of the counter for levels lower than the determination level within a certain time interval is 1 or more. The water leakage determination condition input unit accepts the value of the determination signal level and a water leakage determination criterion to set them to the level comparison unit and the water leakage determination unit.

Description

  The present disclosure relates to a water leakage detection device that detects vibrations and sound generated due to the release of substances in pipes to the ground, such as water leakage, caused by breakage of underground buried objects such as water pipes.

  Conventionally, when detecting the leak position of a pipe, the vibration on the pipe is examined with an ear in an exposed place such as a valve of the pipe to confirm that there is a leak somewhere on the pipe. After checking the vibration at the position where the pipe was likely to be buried in the ground from the surface of the earth, I found the position where the leak sound was best heard, then dug there and examined the pipe. However, it was necessary for skilled workers to perform this method.

  In addition, as another means for detecting the water leakage position, the vibration signal on the pipe is captured and the ratio of the signal above a certain level in the unit time is obtained as a time integral. There is also a way to do it. However, this method is easy to detect when there is a possibility of water leakage, but there is a problem that the determination at a location without water leakage causes ambiguity.

Japanese Patent Laid-Open No. 10-78371

  In the case of leak detection by the above-described conventional method, when a skilled worker performs, or in a single measurement, since it is a method of capturing a leak signal above a certain fixed level, the final leak When the presence / absence determination is performed, there is a problem that it is difficult to determine whether there is a water leak in consideration of the measurement environment depending on the external noise state and the water usage state.

  In order to solve such a conventional problem, the present invention incorporates conditions for the case where there is no water leakage in the final water leakage presence determination, and determines the water leakage determination conditions after measurement according to the environment such as external noise. It is an object of the present invention to provide a water leakage detection device that improves the accuracy of the water leakage determination result and reliably detects no water leakage.

  The water leakage detection device according to the embodiment detects the presence or absence of water leakage by vibration and sound generated by water leakage from a pipe buried in the ground. The water leakage detection device includes a sensor, an A / D conversion unit, a level comparison unit, a counter unit, a water leakage determination unit, and a water leakage determination condition input unit. The sensor is installed in the pipe and captures vibration and sound generated from the pipe. The A / D conversion unit samples the signal captured by the sensor at a predetermined cycle, converts the signal into a digital signal, and outputs the digital signal. The level comparison unit compares a signal level at each sampling timing of the digital signal with a predetermined determination signal level, and outputs a determination result as to whether or not the digital signal has been exceeded. The counter unit is based on the determination result, the counter exceeds a determination level by 1 when the signal level exceeds the determination signal level, and the count value when the signal level is less than the determination signal level. A determination level less than +1 counter is provided. The water leakage determination unit determines water leakage when the ratio of the count value of the counter above the determination level to the count value of the counter below the determination level within a certain time interval is 1 or more. The water leakage determination condition input unit receives the value of the determination signal level and a water leakage determination criterion for a reference when the counter unit counts the count value, and sets the value for the level comparison unit and the water leakage determination unit. .

The block diagram of the water leak detection apparatus which concerns on one Embodiment. The characteristic view which shows the relationship between the frequency | count of sampling by the water leak detection apparatus of FIG. 1, a voltage, and a counter value. The characteristic view which shows the relationship between the frequency | count of sampling by the water leak detection apparatus which concerns on 2nd Embodiment, a voltage, and a counter value. The characteristic view which shows the relationship between the frequency | count of sampling by the water leak detection apparatus which concerns on 3rd Embodiment, and a voltage. The block diagram for demonstrating the effect | action from the measurement start of a voltage by the water leak detection apparatus which concerns on 3rd Embodiment to the end of measurement. The characteristic view which shows the relationship between the frequency | count of sampling by the water leak detection apparatus which concerns on 4th Embodiment, and a voltage. The block diagram for demonstrating the effect | action from the measurement start of a voltage by the water leak detection apparatus which concerns on 4th Embodiment to the end of measurement.

Hereinafter, a water leakage detection device according to an embodiment of the present disclosure will be described.
FIG. 1 is a block diagram of a water leakage detection device according to an embodiment.
The water leakage detection device includes a sensor 1, an amplification unit 2, an A / D conversion unit 3, a central control unit 4, and a water leakage determination condition input unit 5. The sensor 1 is installed in a pipe buried in the ground, detects vibration and sound caused by water leakage from the pipe, and converts them into an electrical signal (sensor signal). For example, an acceleration sensor, a vibration sensor, and a microphone Can be mentioned.

The amplifying unit 2 has a function of amplifying the electric signal. The A / D converter 3 receives a sensor signal, converts it into a digital signal sampled at a predetermined frequency (cycle) generated by a clock from an internal clock supply means (not shown), and outputs the digital signal.
From the water leakage determination condition input unit 5, a water leakage determination condition for determining a combination of determination signal levels is input to the water leakage determination unit 8 described later, and a setting condition for setting the value of the determination signal level L is input to the level comparison unit 10.

  The central control unit 4 includes a waveform shaping unit 9, a level comparison unit 10, a counter unit 11, a calculation result recording unit 7, and a water leakage determination unit that operate based on common timing information such as a clock from an internal clock supply unit (not shown). 8.

  The waveform shaping unit 9 has a function of removing noise from the signal acquired by the sensor 1 and extracting only a signal frequency component required by the level comparison unit 10, and includes a low-pass filter (LPF), a high-pass filter (HPF), a band A filter such as a pass filter (BPF) is used. Here, the waveform shaping unit 9 is composed of a digital filter that processes a digital signal that has been A / D converted, but may be placed in front of the A / D conversion unit 3. Further, a detection process or the like that extracts the envelope of the sensor signal may be performed.

The level comparison unit 10 compares the signal level at each sampling timing of the digital signal input from the waveform shaping unit 9 with a predetermined determination signal level, and determines whether the determination result exceeds or does not exceed the counter unit 11. Output.
The counter unit 11 counts the number of times that the signal level input to the level comparison unit 10 exceeds a predetermined determination signal level. The counter unit 11 counts the number of times that the signal level is less than the determination signal level. It includes a counter-determination level counter (not shown) for counting, and outputs the count values of both counters to the calculation result recording unit 7.

The calculation result recording unit 7 sets a fixed time interval T that is a predetermined measurement period from the clock, and calculates the ratio of the number of times exceeding the determination signal level in the total number of samplings obtained during that time as the calculation result. The calculation result is recorded in a recording medium such as an internal memory of the apparatus or a memory card that can be mounted from the outside.
The water leakage determination unit 8 has a function of estimating the presence / absence of water leakage from the ratio of the number of times each determination signal level is exceeded and the number of times the determination signal level falls below, and the ratio of the number of times the determination signal level exceeds the total sampling number. Have.

  In the central control unit 4, when the signal level in the digital signal exceeds a predetermined determination signal level by the level comparison unit 10, the counter unit 11, or the like, the counter count count (hereinafter referred to as the count value) is greater than the determination level. When the determination signal level falls below a predetermined determination signal level, the count value of the less than determination level counter is set to +1. Further, the count ratio F between the counter value above the determination level and the counter value below the determination level is calculated from the number of counts exceeding the determination signal level within the fixed time interval T and the count value below the determination signal level. When the value of the count ratio F is 1 or more as a water leak determination condition, it is determined that water leaks.

Next, specific embodiments will be described.
(First embodiment)
A first embodiment will be described with reference to FIGS. 1 and 2A to 2C. In 1st Embodiment, the signal component resulting from a water leak is applied to the water leak generation | occurrence | production state which is simply added to the amplitude of a sensor signal.
Here, FIG. 2 (A) is a characteristic diagram showing the signal level (voltage) of the sensor signal at a fixed time interval (T) as the measurement time, and FIG. 2 (B) is a signal level corresponding to FIG. 2 (A). FIG. 2C is a characteristic diagram showing a count value when (voltage) exceeds the determination voltage level ± L, and FIG. 2C corresponds to FIG. 2A, and the signal level (voltage) does not exceed the determination voltage level ± L. The characteristic figure which shows the count value in a case is shown.

  In the case of the first embodiment, the setting of adopting a water leak judgment criterion that counts according to whether the value of the judgment signal level ± L and the input signal are within the range of the judgment signal level ± L or exceeded is the water leakage This is performed from the determination condition input unit 5. As the value of L itself, several candidate values are stored in advance in the water leakage determination condition input unit 5 as adjustment values, and the values are notified to the level comparison unit 10.

  In addition, although not shown, the counter unit 11 is a counter greater than a determination level (counter greater than L) that counts the number of times that the determination signal level (+ side: + L, − side: −L) is exceeded, and is lower than the determination signal level. And a determination level less than counter (less than L counter).

First, a digital signal obtained by performing A / D conversion on a signal acquired on a pipe by a sensor 1, for example, a microphone, by sampling at a frequency of 10 kHz, for example, is input to the level comparison unit 10 through the waveform shaping unit 9. .
In the level comparison unit 10, when the input signal level exceeds the determination signal level (+ side: + L,-side: -L), the count value of the counter is incremented by +1 as L or more, and the signal level changes the determination signal level. If it falls below, the count value of the less than L counter is incremented by +1. This count value is notified to the calculation result recording unit 7.

  Then, the calculation result recording unit 7 finally counts the counter L or more at which the signal level exceeds the determination signal level when a predetermined time interval T as a measurement time elapses such as 10 seconds elapses. The ratio (count ratio F) between the value Lu and the count value L1 of the less-L counter whose signal level is lower than the determination signal level is obtained from the following equation (1) and notified to the water leakage determination unit 8.

Here, the water leakage determination unit 8 determines that there is water leakage when the count ratio F is 1 or more based on the water leakage determination condition input and set in advance from the water leakage determination condition input unit 5. Judged as none.
F = number of samplings exceeding L / number of samplings not exceeding L
= L or more Count value Less than Lu / L Count value L1 (1)
According to the first embodiment, the sensor 1, the amplification unit 2, the A / D conversion unit 3, the central control unit 4, and the like are provided, and a sensor signal including a signal component caused by water leakage taken in by the sensor 1 is sampled in a predetermined manner. Sampling is performed at a period, and the digital signal is converted by the A / D converter 3.

  Each count value is obtained when the signal level exceeds a predetermined determination signal level ± L by the digital signal value and when the signal level falls below the determination signal level ± L, and the ratio is determined to be 1 or more and less than 1 Thus, the presence or absence of water leakage can be estimated. That is, when it exceeds the signal level for judgment, it contains many signals due to water leakage, and when it falls below the signal level for judgment, it contains many signals other than those caused by water leakage. It is easy to detect the location where there is water leakage as well as the location where there is no water leakage.

(Second Embodiment)
A second embodiment will be described with reference to FIGS. 1 and 3A to 3C. The second embodiment is basically the same as the first embodiment, but the determination signal level has hysteresis.
Here, FIG. 3A is a characteristic diagram showing a sensor signal in a fixed time interval (T), that is, a measurement period, and FIG. 3B is a determination voltage corresponding to FIG. FIG. 3C is a characteristic diagram showing the counter value when the level does not exceed the determination signal level voltage level ± L2, and FIG.

  In FIG. 3, the signal acquired on the pipe by the sensor is subjected to A / D conversion while sampling at a constant interval, and the level of the signal is the upper limit determination signal level (+ side: + L1, -Side: When -L1) is exceeded, the count of L1 or more is incremented as +1, and when the signal level falls below the lower limit judgment signal level (+ side: + L2,-side: -L2), Increment as +1. Then, sampling is performed for a predetermined time interval T, and when the predetermined time interval T finally elapses, the number of counters above the upper limit L1 at which the signal level exceeds the upper limit determination signal level Then, the sampling ratio F of the number of times of the lower limit L2 counter that the signal level is lower than the lower limit determination signal level is obtained from the following formula (2), and based on the result, water leakage is determined based on the water leakage determination condition.

F = number of sampling times exceeding L1 / number of sampling times not exceeding L2 = count value greater than or equal to L1 / count value less than L2 (2)
According to the second embodiment, when a predetermined fixed time interval T elapses, the counter more than the upper limit determination level is determined by the number of sampling times exceeding the upper limit determination signal level and the number of sampling times lower than the lower limit determination signal level. The count ratio F of the count value with the lower limit determination level counter is calculated, and when the value of this ratio is 1 or more, it can be determined that there is water leakage. Therefore, according to the second embodiment, it is possible to obtain the advantage of having a hysteresis effect by suppressing L2 to be smaller than L1, and suppressing malfunction when the amount of leaked water fluctuates. The same effect can be obtained.

(Third embodiment)
A third embodiment will be described with reference to FIG. 1, FIG. 4, and FIG. In the third embodiment, it is possible to cope with a case where the signal component due to water leakage affects the sensor signal generated from the surroundings in the normal state in a reverse phase and cancels out.
Here, FIG. 4 is a characteristic diagram showing the relationship between the constant time interval T and the signal level, and FIG. 5 is a flowchart showing the process from the start of measurement of water leakage to the end of measurement using the water leakage detection device of FIG.

  First, after the sampling value (measurement value) is input (step S1 in FIG. 5), the signal acquired on the pipe by the sensor 1 is A / D converted, and the level of the signal with respect to the digital signal has a plurality of determination signal levels. When each of (± L1, ± L2, ± L3, ± L4) is exceeded, each count value of each L1 counter to L4 counter is incremented by +1 (steps S2 to S5 in FIG. 5).

  That is, when the level of the signal exceeds the determination signal level (± L1), the count value of the L1 counter is incremented by +1 (step S2 in FIG. 5). When the level of the signal exceeds the determination signal level (± L2), the count value of the L2 counter is incremented by +1 (step S3 in FIG. 5). When the level of the signal exceeds the determination signal level (± L3), the count value of the L3 counter is incremented by +1 (step S3 in FIG. 5). When the level of the signal exceeds the determination signal level (± L4), the count value of the L4 counter is incremented by +1 (step S4 in FIG. 5). Each of the determination signal levels (± L1, ± L2, ± L3, ± L4) is input and set from the water leakage determination condition input unit 5 to the level comparison unit 10.

  Then, while performing this processing for a single sampling, sampling is performed for a predetermined time interval T. Finally, when the predetermined time interval T elapses, the signal level is changed. A plurality of count values of an L1 counter to an L4 counter that count the number of times when a plurality of determination signal levels (± L1 to ± L4) are exceeded, and a total number of samplings Q during a predetermined fixed time interval T The ratio is obtained (step S7 in FIG. 5). Here, when the total number of sampling times becomes equal to or greater than Q, the count ratios F1 to F4 of the L1 counter to L4 counter are calculated. If the total number of sampling times is less than Q (step S6 in FIG. 5), sampling is repeated (sampling data). Continue to input).

The water leakage determination unit 8 counts the ratios of the L1 counter to the L4 counter measured in the same procedure as described above on the piping to be investigated when there is no water leakage or no abnormality in the surroundings when the fixed time interval T elapses and the measurement ends. Compare with F1-F4. At least one or more count ratio arrangement patterns or typical ratio data are stored in the internal memory of the water leakage determination unit 8 as determination criteria. Then, the water leakage determination unit 8 sets which of the determination reference patterns is adopted in the water leakage determination condition input unit 5 (the determination reference data is stored in the water leakage determination condition input unit 5 and the data is stored in the water leakage determination unit 8. (It may be input as a judgment criterion.)
For example, when normal, the count ratio is F1>F3>F2> F4 at the end of the measurement for investigating water leakage, as compared to the case where the count ratios are arranged in the order of F1>F2>F3> F4 as a reference pattern. If the patterns are different as in the case of, it is determined that there is water leakage.
Moreover, if it is known in advance that the count ratio F2 will be the largest at the time of water leakage instead of the arrangement pattern of the determination criteria, the presence or absence of water leakage can be determined by examining the maximum count ratio. .

  According to the third embodiment, when each of the predetermined determination signal levels (± L1, ± L2, ± L3, ± L4) is exceeded, the count value for each determination signal level is set to +1, and the final The count ratios F1 to F4 between the respective count values exceeding the determination signal level within the predetermined time interval T and the total number of samplings Q are obtained, and which of the plurality of determination levels is determined from the ambient environment conditions at the time of measurement. It is possible to determine whether there is a water leak by selecting whether to perform the determination using the count ratio of the determination signal level, and to improve the detection probability of water leakage.

(Fourth embodiment)
The fourth embodiment relates to automatic determination signal level setting processing.

  A fourth embodiment will be described with reference to FIGS. Here, FIG. 6 is a characteristic diagram showing a signal level at a measurement time and a fixed time interval (T), and FIG. 7 is a flowchart showing a process from the start of measurement of water leakage to the end of measurement using the water leakage detection device of FIG. . In the fourth embodiment, the leakage signal is detected by automatically acquiring and storing the determination signal level at the place where the sensor is installed in the pipe where it is already known that the leakage point exists. Applied to the detection device.

  Here, in the water leak detection device to which the third embodiment is applied, first, after inputting a sampling value (step S10 in FIG. 7), for example, in a water pipe that has already been found to have water leak, a sensor 1 to obtain a sensor signal (step S11 in FIG. 7). Then, while sampling at a predetermined sampling cycle, if the level of the signal that has been A / D converted and the digital signal exceeds the determination signal level L at the initially set determination signal level, the count value of the L counter is set. Increment as +1 (step S12 in FIG. 7). Then, sampling is performed until a predetermined time interval T is reached, and when the predetermined time interval T finally elapses, the number of times when the signal level exceeds the determination signal level L is counted. The ratio between the count value of the counter to be used and the total number of samplings Q during a predetermined time interval T is determined (step S14 in FIG. 7). Here, the count ratio Fa1 is calculated when the total number of samplings is equal to or greater than the above, but when the total number of samplings is less than Q (step S13 in FIG. 7), the input of the sampling value is repeated.

  Further, if the count ratio Fa1 is equal to or greater than a predetermined value determined in advance as 0.6 (step S15 in FIG. 7), the determination signal level value L is stored (FIG. 7). In step S17), the measurement ends. On the contrary, if the count ratio Fa1 is less than the specified value, the value of the determination signal level L is measured while adjusting the determination signal level value L so that it is further lowered (step S16 in FIG. 7). The value of the determination signal level L from which the specified value is obtained is written and stored in the memory means of the water leakage determining unit 8.

  Conversely, when it is desired to reduce the count ratio, the value of the determination signal level L is adjusted to be further increased. Similarly, the determination signal level L may be set for a plurality of L counters.

  Further, in order to obtain the value of the determination signal level L corresponding to the first embodiment, the count ratio Fa of the count value L / total sampling Q may be set to 0.5 ± 0.5.

  According to the fourth embodiment, the central control unit 4 sets the count value to +1 when the signal level of the input sampling value exceeds a predetermined determination signal level L, and is finally constant. The number of times that the determination signal level is exceeded within the time interval T is counted, and the count ratio Fa1 of the number of times that the determination signal level is exceeded with respect to the total sampling number Q is obtained and stored.

  In the fourth embodiment, the leak detection in the first to third embodiments is performed by notifying the stored determination signal level from the leak detection unit 8 to the level comparison unit 10 after the above initial setting work. Is possible.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Sensor, 2 ... Amplification part, 3 ... A / D conversion part, 4 ... Central control part, 5 ... Water leak determination condition input part, 7 ... Calculation result recording part, 8 ... Water leak determination part, 9 ... Waveform shaping part, 10: level comparison unit, 11: counter unit.

Claims (4)

A water leakage detection device for detecting the presence or absence of water leakage by vibration or sound caused by water leakage from a pipe buried in the ground,
A sensor that is installed in a pipe and captures vibration and sound generated from the pipe;
An A / D converter that samples the signal captured by the sensor at a predetermined period, converts the signal into a digital signal, and outputs the digital signal;
A level comparison unit that compares a signal level for each sampling timing of the digital signal with a predetermined determination signal level, and outputs a determination result of whether or not exceeded,
Based on the determination result, when the signal level exceeds the determination signal level, a counter that is greater than or equal to a determination level that increments the count value, and when the signal level is less than the determination signal level, the determination level that increments the count value by 1 A counter unit comprising a less than counter,
A water leakage determination unit that determines water leakage when the ratio of the count value of the counter above the determination level to the count value of the counter below the determination level within a certain time interval is 1 or more;
Receiving a value of the determination signal level and a water leakage determination criterion for a reference when the counter unit counts the count value, and a water leakage determination condition input unit set for the level comparison unit and the water leakage determination unit; A water leakage detection device comprising: The determination level or higher counter and the determination level less than counter each have a function of detecting a predetermined upper limit determination signal level and a predetermined lower limit determination signal level lower than the upper limit determination signal level,
When the signal level in the digital signal exceeds the upper limit determination signal level, the counter above the determination level is set to +1, and when the signal level falls below the lower limit determination signal level, the less than determination level counter is set. When +1 is set and the ratio of the counter above the judgment level to the counter below the judgment level based on the number of samplings exceeding the upper limit judgment signal level and the number of samplings below the lower judgment signal level within a certain time interval is 1 or more The water leakage detection device according to claim 1, wherein The determination level or higher counter and the determination level less than counter each have a function of detecting three or more determination signal levels,
When the signal level in the digital signal exceeds each determination signal level, the counter above each determination level is set to +1, and the number of sampling times exceeding the respective determination signal level within a predetermined time interval and the total number of sampling times The leak detection according to claim 1, wherein a plurality of ratios are obtained, and a determination signal level sampling ratio is selected from among a plurality of determination signal levels based on ambient environmental conditions at the time of measurement. apparatus. It is a water leak detection device in which the sensor is installed in a pipe that is known to have water leak in advance,
When the signal level in the digital signal exceeds the judgment signal level, the counter above the judgment level is set to +1, and the number of sampling times exceeding the judgment signal level within a predetermined time interval is calculated by the counter above the judgment level, and total sampling is performed. The ratio of the number of sampling times exceeding the judgment signal level in the number of times was obtained and measured while varying the judgment signal level until the sampling ratio became a certain value or more, and the sampling ratio became a certain value or more. The leak detection device according to claim 1, wherein the determination signal level for determining leakage is automatically determined based on the determination signal level in the case.

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