JP6523919B2 - Method of judging abnormality of pipeline - Google Patents

Description

  The present invention relates to a determination method for determining an abnormality in a conduit.

  Conventionally, vibration data was measured by piezoelectric sensors installed at two or more inspection positions, and a cross correlation function was obtained based on the two or more vibration data. And the existence of water leakage was judged from the cross correlation function.

  For example, in the invention according to Patent Document 1 (Japanese Patent Application Publication No. 2003-502678), two input signals are detected from a fluid transport pipe, the phase of the input signal in the frequency domain is determined, and at least one filter is provided. And the input signal is filtered and cross-correlation of the filtered signal is performed.

  On the other hand, in the invention according to Patent Document 2 (Japanese Patent Application Laid-Open No. 8-121700), sound pressure data is collected at a predetermined position in a buried pipe for a predetermined sampling time and for a predetermined measurement time, and sound pressure data collected The frequency distribution related to the sound pressure level is formed, and the presence or absence of leakage in the buried conduit is determined by the degree of concentration of the sound pressure data in this frequency portion.

Japanese Patent Publication No. 2003-502678 JP-A-8-121700

  However, in the invention according to Patent Document 1, vibration data is measured by piezoelectric sensors installed at two or more inspection positions, and a cross correlation function is obtained based on the two or more vibration data. And if the vibration by water leakage is not input from the cross correlation function, there exists a problem that a water leakage can not be detected.

  On the other hand, in the invention according to Patent Document 2, the sound pressure in the conduit is measured for a predetermined time, and it is determined that the water leakage occurs when the sound pressure is concentrated to a constant value.

  Therefore, in a quiet environment with little noise, the sound pressure may be constant even if no water leakage occurs, and there is a problem that accurate determination can not be made.

  The main object of the present invention is to provide a method for judging abnormality of a conduit which can judge the abnormality of the conduit based on the calculated judgment value in order to solve such a problem. Another object of the present invention is to provide a method of judging abnormality of a conduit which can determine abnormality of the conduit at one inspection position.

(1)
A method of judging abnormality of a conduit according to one aspect is a method of judging abnormality of the conduit, wherein vibration data measurement is performed to measure vibration of the conduit for a predetermined time at at least one inspection position to obtain vibration data Process, waveform pattern extraction process of extracting a partial waveform pattern from at least one vibration data obtained in vibration data measurement process, waveform pattern obtained in waveform pattern extraction process, and vibration data measurement process A pipeline including a cross correlation process for obtaining a cross correlation function with vibration data, and a determination value calculation process for calculating a determination value from the amplitude of the cross correlation function obtained in the cross correlation process, and based on the calculated determination value To determine the abnormality of

  For example, if the water leakage is occurring in the pipeline, the generation source is the same, so that a unique waveform pattern derived from the water leakage occurs. And the waveform pattern is generated continuously in time series. That is, of the vibration data in time series, a unique waveform pattern derived from water leakage is measured.

  Therefore, by obtaining the cross-correlation function between the waveform data of a part of the vibration data and the vibration data, which is arbitrarily extracted, a portion of the waveform pattern repeated in the vibration data (for example, a specific waveform part due to water leakage) The correlation value increases.

  Therefore, the value (decision value) calculated from the amplitude of the cross correlation function is a unique value according to the environment of the conduit. As a result, an abnormality in the conduit can be determined based on the calculated determination value.

(2)
According to another aspect of the present invention, there is provided a method of judging abnormality of a conduit, wherein the abnormality of the conduit is judged, and vibration data measurement is performed to measure vibration of the conduit for a predetermined time at one inspection position. Process, waveform pattern extraction process for extracting a plurality of waveform patterns from one vibration data obtained in vibration data measurement process, and a plurality of waveform patterns obtained in the waveform pattern extraction process and vibration data measurement process Based on the calculated determination value, the method includes a cross correlation step of obtaining a cross correlation function with one vibration data, and a determination value calculation step of calculating a determination value from the amplitude of the cross correlation function obtained in the cross correlation step. , Determine the abnormality of the pipeline at one inspection position.

  Arbitrary plural waveform patterns are extracted from one vibration data. Then, a cross correlation function between the plurality of waveform patterns and one vibration data before extraction is obtained. As a result, in the portion of the waveform pattern repeated in the vibration data (for example, the inherent waveform portion due to water leakage), the correlation value becomes large.

  Therefore, the value (decision value) calculated from the amplitude of the cross correlation function is a unique value according to the environment of the conduit. As a result, an abnormality in the conduit can be determined based on the calculated determination value. That is, it is possible to determine the abnormality of the pipeline at one inspection position.

(3)
The method for determining a pipe line abnormality according to the third invention is a method for determining a pipe line abnormality according to one aspect or another aspect, wherein the determination value calculating step includes cross correlation obtained in the cross correlation step. The determination value relatively indicating the magnitude of the correlation is calculated from the amplitude of the function, and the calculated determination value is compared with a predetermined determination value to determine an abnormality in the conduit.

  “To relatively indicate the magnitude of correlation” means, for example, calculating the maximum value of each of a plurality of cross correlation functions and taking the average value. It also includes dividing the average value of the maximum values by the average value of the positive part of the cross correlation function.

  The value (decision value) relatively indicating the magnitude of the correlation from the amplitude of the cross correlation function is a unique value according to the environment of the conduit. Then, determination values under various environments are calculated in advance (predetermined determination values). Then, the judgment value of the conduit to be examined is calculated.

  Then, by comparing the calculated determination value with a predetermined determination value, it can be known which value of the predetermined determination value the calculated determination value corresponds to. As a result, it is possible to determine an abnormality in the conduit.

(4)
The method of determining pipe line abnormality according to the fourth invention is a method of judging pipe line abnormality according to the third invention, wherein the calculated judgment value is the upper limit of the predetermined range of the judgment value determined in advance. If the value is exceeded, it is determined that the conduit is vibrating due to mechanical vibration.

  In the case of mechanical vibration, since the regularity of the vibration is strong, the correlation value between the vibration data and the waveform pattern becomes large. As a result, the judgment value also increases. From this, when the calculated determination value is a value exceeding the upper limit value of the predetermined range, it is possible to determine that the vibration is mechanical vibration. If the mechanical vibration can be determined, the cause of the abnormality of the conduit can be estimated.

(5)
The method of determining a conduit abnormality according to the fifth invention is the method of determining a conduit abnormality according to the third invention or the fourth invention, wherein the calculated determination value is within a predetermined range, It is determined that water leakage has occurred in the pipeline.

  Since the leak source is the same source, there is an inherent waveform pattern. And, water leakage occurs continuously. As a result, the correlation value between the waveform pattern and the vibration data becomes large. That is, although the value is lower than the mechanical vibration, the calculated determination value becomes large. Therefore, when it is in the predetermined range of the judgment value defined beforehand, it can be judged that water leakage has arisen.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram in one Embodiment of this invention. The flowchart of the determination method of the pipe line abnormality in one Embodiment of this invention. The flowchart of the determination method of the pipe line abnormality in one Embodiment of this invention. The schematic diagram which extracts the waveform pattern in one Embodiment of this invention. The schematic diagram which calculates the value of the cross correlation of vibration data and waveform pattern in one Embodiment of this invention. The determination table arranged in order of the determination value in one Embodiment of this invention. The determination table arranged in order of the determination value in one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed description about them will not be repeated.

  FIG. 1 is a schematic view in which a piezoelectric sensor 200 which is a vibration sensor installed in a pipe 100 which is a pipe line detects a vibration of the pipe 100. The vibration data detected by the piezoelectric sensor 200 is sent to the control device 300. The method of transmitting vibration data from the piezoelectric sensor 200 to the control device 300 may be wired or wireless.

  Control device 300 includes at least storage unit 310 and operation unit 320. The controller 300 is connected to the monitor 400. The controller 300 can graph the vibration data sent from the piezoelectric sensor 200, and the monitor 400 can display the graph.

<Flowchart 1 of method of judging abnormality of pipeline>
FIG. 2 is a flow chart of a method of determining a conduit abnormality according to one aspect of the present invention. First, the piezoelectric sensor 200 detects the vibration of the pipe 100. The piezoelectric sensor 200 measures vibration of the pipe 100 for a predetermined time to obtain vibration data (step S11). The piezoelectric sensor 200 transmits the detected vibration data to the control device 300.

  Next, the control device 300 causes the storage unit 310 to store the vibration data obtained from the piezoelectric sensor 200. Then, the control device 300 extracts a plurality of waveform patterns from the stored vibration data (step S12). The extraction of the waveform pattern may be performed while the operator looks at the vibration data on the monitor 400.

  The waveform pattern to be extracted is one for an arbitrary time zone, but it is preferable that the sound pressure level is average without an obvious noise.

  The extracted waveform pattern includes, for example, a waveform pattern unique to water leakage if water leakage occurs. However, there are many cases where the operator can not judge even if they look at vibration data. Therefore, a cross correlation function between the waveform pattern and the vibration data is obtained.

  Specifically, control device 300 obtains a cross-correlation function from vibration data and each waveform pattern in operation unit 320 (step S13). Control device 300 moves each waveform pattern little by little according to a time series (time axis), and obtains a cross correlation function for each time. The obtained cross correlation function is graphed and displayed on the monitor 400.

  When water leakage occurs, the waveform pattern unique to the water leakage is included in both the extracted waveform pattern and the vibration data. Therefore, if the cross correlation function between the extracted waveform pattern and the vibration data is determined, the correlation value becomes large.

  On the other hand, when mechanical vibration is occurring, the mechanical vibration is an inherent waveform pattern. The waveform pattern of the mechanical vibration is included in both the extracted waveform pattern and the vibration data. Furthermore, regularity is higher than in the case of water leakage. Therefore, if the cross correlation function between the extracted waveform pattern and the vibration data is determined, the correlation value becomes larger than in the case of water leakage. That is, it is possible to distinguish between water leakage and mechanical vibration.

  Next, the calculation unit 320 calculates a determination value from the amplitude of the cross correlation function obtained in step S13 (step S14).

  Specifically, cross correlation functions are obtained at many points along the time series of the extracted waveform pattern and vibration data. Then, the respective maximum values are calculated, and an average value of the maximum values is obtained. This value may be used as the determination value. The average value approaches a constant value as the calculated number increases. Also, in some cases, the average value of the maximum value is divided by the average value of the portion where the cross correlation function is positive. This value may be used as the determination value.

  By calculating so-called judgment values in this way, comparison with other environments becomes easier.

  Next, it is determined whether water leakage has occurred in the pipe 100 by comparing the determined determination value with a predetermined determination value.

  Thus, the presence or absence of water leakage can be determined by comparing the determined determination value with a predetermined determination value. Moreover, it can be determined by this determination method whether the abnormality of the pipeline is mechanical vibration or not.

  In summary, it is as follows. Unlike the case of noise etc, when the water leakage is occurring, the source is the same. Therefore, there is a unique waveform pattern corresponding to the water leakage. And, in the case of water leakage, the waveform pattern is generated continuously.

  Therefore, when part of the vibration data obtained by the same piezoelectric sensor 200 is extracted and the cross correlation function between the waveform pattern and the vibration data is calculated, the value of the cross correlation function becomes large.

  Further, since the water leakage occurs continuously, when the cross correlation function is calculated a plurality of times, the value of the cross correlation function tends to be a constant value.

  On the other hand, the mechanical vibration of the sound generated by the pump or the motor is stronger in the regularity of the waveform compared to the vibration of the leakage water. As a result, the value of the cross-correlation function exhibits a higher value than in the case of water leakage. Therefore, the case of water leakage and the case of mechanical vibration can be distinguished.

<Flowchart 2 of method of judging abnormality of pipeline>
FIG. 3 is a flow chart of a method of determining a conduit abnormality according to another aspect of the present invention. The same parts as the flowchart 1 described above will be omitted.

  The piezoelectric sensor 200 measures the vibration of the pipe 100 for a predetermined time at one inspection position to obtain vibration data (step S21). The piezoelectric sensor 200 transmits the detected vibration data to the control device 300.

  Next, the control device 300 causes the storage unit 310 to store one vibration data obtained from the piezoelectric sensor 200. Then, control device 300 extracts a plurality of waveform patterns from one stored vibration data (step S22).

  Control device 300 obtains a cross-correlation function from one vibration data and each waveform pattern in operation unit 320 (step S23). The control device 300 moves each waveform pattern little by little according to the time series (time axis), and calculates the cross correlation function for each time.

  That is, a cross-correlation function is obtained between a plurality of waveform patterns in an arbitrary time zone extracted from one vibration data and the vibration data before extraction. For example, if leakage occurs in the pipeline, the waveform pattern of the leakage is included in the extracted waveform pattern as well as in the vibration data. Therefore, the correlation value becomes large in a portion where there is a waveform pattern of water leakage in the vibration data.

  Similarly, in the case of mechanical vibration, the waveform pattern of water leakage is included in the extracted waveform pattern as well as in the vibration data. Therefore, the correlation value becomes large in the portion where the waveform pattern of the mechanical vibration of the vibration data is present. In the case of mechanical vibration, the correlation value is larger than in the case of water leakage because the regularity is higher than the water leakage.

  Next, the calculation unit 320 calculates a determination value from the amplitude of the cross correlation function obtained in step S23 (step S24). How to obtain the determination value is as described above.

  From these facts, it is possible to determine an abnormality in the conduit even at one detection position.

Examples (Examples 1 and 2) will be described below.
Example 1
As shown in FIG. 4, the vibration of the pipe 100 is measured for 50 seconds by the piezoelectric sensor 200 attached to the pipe 100. Then, three arbitrary waveform (waveform patterns) of 0.1 second are extracted (A, B, C) from the 50-second waveform.

  Next, as shown in FIG. 5, for each of the extracted waveform patterns A (B, C), vibration data of 0 sec or more and 0.1 sec or less and a cross correlation function are obtained (n1). Next, the waveform pattern A (B, C) moves by 0.05 msec. Then, a cross correlation function is obtained with the waveform pattern A (B, C) and vibration data of 0.05 msec or more and 100.05 msec or less (n2, not shown).

  This operation is similarly repeated to obtain cross correlation functions from n1 to n1,000,000. When n1 is the first, nk indicates the k-th. This operation is similarly performed on the waveform pattern B and the waveform pattern C other than the waveform pattern A.

  That is, the waveform pattern A obtains one million cross correlation functions. Similarly, 1 million cross-correlation functions are calculated for each of the waveform patterns B and C, respectively. As a result, a total of 3 million cross correlation functions are obtained.

  As described above, the maximum value of the cross correlation function is calculated in all of the calculated 3,000,000 cross correlation functions. Then, the average value of the maximum values of the three million cross correlation functions is calculated. Next, the average value of the portion where the cross correlation function is positive among the three million cross correlation functions is calculated. The determination value is calculated from the average value of the maximum values and the average value of the positive part.

The judgment value is calculated by the following equation.
Judgment value = [average value of maximum values of cross correlation function] / [average value of portions where cross correlation function is positive] (1)

  As shown in FIG. 6, determination values are calculated under various conditions, and a first determination table 500 is created. In the first determination table 500, the range of the portion where water leakage is generated is taken as a predetermined range P1. Further, the predetermined range P1 includes the upper limit value H1 and the lower limit value L1.

  In FIG. 6, the upper limit H1 of the predetermined range P1 is 0.25, and the lower limit L1 is 0.10. The determination value of a value higher than the upper limit value H1 is a mechanical noise such as a pump noise, that is, a mechanical vibration. In addition, a judgment value of a value lower than the lower limit L1 is judged to be no water leakage.

  Specifically, when the determination value is 0.10 or less, it is determined that water leakage has not occurred. If the judgment value is more than 0.10 and not more than 0.25, it is judged that water leakage has occurred. If the judgment value exceeds 0.25, it is judged as mechanical noise, that is, mechanical vibration.

  For example, it is assumed that the determination value is calculated in accordance with the flowcharts shown in FIGS. The calculation method of the determination value follows the equation (1) above.

  Then, it is assumed that the determination value is, for example, 0.15. In this case, since 0.15 exceeds 0.10 and is 0.25 or less, it corresponds to the predetermined range P1. That is, it can be determined that water leakage has occurred in the pipe 100.

  In this case, it is not necessary to obtain vibration data at two or more locations of the pipe 100, and it can be determined whether water leakage has occurred at that location.

  As a specific example, a piezoelectric sensor was installed on the valve of water pipe VP50, and vibration was measured. At this time, since the judgment value was 0.21, when drilling was carried out by boring around the valve, water leakage was actually generated. In addition, "VP" means a rigid vinyl chloride pipe.

  Next, a piezoelectric sensor was installed on the valve of another water pipe VP50, and vibration was measured. At this time, since the judgment value was 0.44, when the surroundings were examined, this was the pump noise of the septic tank.

  A piezoelectric sensor was installed on the valve of the water pipe DCIP 100, and the vibration was measured. At this time, since the judgment value was 0.24, when drilling around the valve was conducted by drilling, water leakage was actually generated. In addition, "DCIP" means a doug tile cast iron pipe.

Example 2
The same parts as in the first embodiment are omitted. In the second embodiment, the maximum value of the cross correlation function is calculated in all of the calculated 3,000,000 cross correlation functions. Then, the average value of the maximum values of the three million cross correlation functions is calculated.

The determination value is calculated by the following equation.
Judgment value = average of maximum value of cross correlation function (2)

  As shown in FIG. 7, determination values are calculated under various conditions, and a second determination table 600 is created. In the second determination table 600, the range of the portion where water leakage is generated is taken as a predetermined range P2. Further, the predetermined range P2 includes the upper limit value H2 and the lower limit value L2.

  In FIG. 7, the upper limit H2 of the predetermined range P2 is 0.70, and the lower limit L2 is 0.40. The determination value of a value higher than the upper limit value H2 is mechanical noise such as pump noise, that is, mechanical vibration. Further, the judgment value of a value lower than the lower limit value L2 is judged to be no water leakage.

  Specifically, when the determination value is 0.40 or less, it is determined that water leakage has not occurred. If the judgment value is more than 0.40 and not more than 0.70, it is judged that water leakage has occurred. If the judgment value exceeds 0.70, it is judged as mechanical noise, that is, mechanical vibration.

  For example, it is assumed that the determination value is calculated in accordance with the flowcharts shown in FIGS. The method of calculating the determination value follows the equation (2) above. Then, if the determination value is, for example, 0.45, it is 0.40 or more and 0.70 or less, and thus falls within the predetermined range P2. That is, it can be determined that water leakage has occurred in the pipe 100.

  A piezoelectric sensor was installed on the valve of water pipe VP100, and vibration was measured. At this time, since the judgment value was 0.61, drilling was carried out by boring around the valve, and water leakage was actually generated.

  Next, a piezoelectric sensor was installed on the valve of another water pipe VP50, and vibration was measured. At this time, as the judgment value was 0.88, the surroundings were examined. As a result, there was a vending machine on the pipeline and it was vibrating.

  A piezoelectric sensor was installed on the valve of the water pipe DCIP 100, and the vibration was measured. At this time, since the judgment value was 0.64, drilling was carried out by boring around the valve, and water leakage was actually generated.

  As described above, according to the method of determining a pipe line abnormality according to the present embodiment, the abnormality of the pipe 100 can be determined based on the calculated determination value. Moreover, the abnormality of the piping 100 can be determined even at one inspection position.

  Further, by comparing the calculated determination value with a predetermined determination value, it can be known which value of the predetermined determination value the calculated determination value corresponds to. That is, it can be determined whether water leakage has occurred based on which value of the first determination table or the second determination table the calculated determination value is in.

  When the calculated determination value exceeds the upper limit values H1 and H2 of the predetermined ranges P1 and P2 of the determination values determined in advance, it can be determined that the pipe is vibrating due to mechanical vibration. As a result, if the mechanical vibration can be determined, the cause of the vibration of the pipe 100 can be estimated.

  In addition, when the calculated determination value is within predetermined ranges P1 and P2 of the determination values determined in advance, it can be determined that water leakage has occurred.

  In the present invention, the pipe 100 corresponds to the "pipe", the piezoelectric sensor 200 corresponds to the "vibration sensor", the predetermined ranges P1 and P2 correspond to the "predetermined range", and the upper limit H is the "upper limit". And the lower limit L corresponds to the “lower limit”.

  In the present invention, step S11 corresponds to the "vibration data measurement step", step S12 corresponds to the "waveform pattern extraction step", step S13 corresponds to the "cross-correlation step", and step S14 corresponds to the "determination value It corresponds to "calculation process".

  In the present invention, step S21 corresponds to the "vibration data measurement step", step S22 corresponds to the "waveform pattern extraction step", step S23 corresponds to the "cross-correlation step", and step S24 corresponds to "determination value It corresponds to "calculation process".

  Although a preferred embodiment of the present invention is as described above, the present invention is not limited thereto. It is also possible to determine an abnormality from a plurality of indicators by combining with an existing determination method such as the degree of concentration of sound pressure data. It will be understood that various other embodiments may be made without departing from the scope of the spirit of the invention. Furthermore, in the present embodiment, actions and effects according to the configuration of the present invention are described, but these actions and effects are only examples and do not limit the present invention.

100 Piping (pipe line)
200 Piezoelectric sensor (vibration sensor)
300 control device 310 storage unit 320 operation unit 400 monitor 500 first judgment table 600 second judgment table

Claims (4)

It is a determination method for determining an abnormality in a pipeline,
A vibration data measurement step of measuring vibration of a conduit for a predetermined time at one inspection position to obtain vibration data;
A waveform pattern extraction step of extracting a plurality of waveform patterns from one piece of the vibration data obtained in the vibration data measurement step;
Obtaining a cross-correlation function between the plurality of waveform patterns obtained in the waveform pattern extraction step and the one vibration data obtained in the vibration data measurement step;
A determination value calculation step of calculating a determination value from the amplitude of the cross correlation function obtained in the cross correlation step;
The abnormality determination method of a pipe line which determines the abnormality of the said pipe line at one test position based on the calculated said judgment value. The determination value calculation step is to calculate a determination value indicating the magnitude of the correlation relatively from the amplitude of the cross correlation function obtained in the cross correlation step.
The pipe line abnormality judging method according to claim 1, wherein the abnormal vibration of the pipe line is judged by comparing the calculated judgment value with a predetermined judgment value. The pipe line abnormality judgment according to claim 2 , wherein the pipe line is judged to be vibrating due to mechanical vibration when the calculated judgment value exceeds an upper limit value of a predetermined range of the judgment value set in advance. Method. The method for determining abnormality of a conduit according to claim 2 or 3 , wherein it is determined that water leakage has occurred in the conduit if the calculated determination value is within the predetermined range.

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