JP2017083292A - Method for determining abnormality of pipe line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for determining the abnormality of a pipe line, enabling the abnormality of the pipe line to be determined on the basis of a calculated determination value.SOLUTION: The method for determining the abnormality of a pipe line according to the present invention includes at least: a vibration data measurement step of measuring the vibration of a pipe line 100 for a prescribed time in at least one inspection position thereby obtaining vibration data; a waveform pattern extraction step of extracting a partial waveform pattern from the vibration data obtained in the vibration data measurement step; a cross-correlation step of obtaining the cross-correlation function of the waveform pattern obtained in the waveform pattern extraction step with the vibration data obtained in the vibration data measurement step; and a determination value calculation step of calculating a determination value using the amplitude of the cross-correlation function obtained in the cross-correlation step, the method determining the abnormality of the pipe line 100 on the basis of the calculated determination value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a determination method for determining an abnormality of a pipeline.

  Conventionally, 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 the presence or absence of water leakage was judged from the cross correlation function.

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

  On the other hand, the invention according to Patent Document 2 (Japanese Patent Application Laid-Open No. 8-121700) collects sound pressure data over a predetermined measurement time at a predetermined sampling time at an appropriate location in the buried conduit, and the collected sound pressure data. A frequency distribution relating to the sound pressure level is formed, and the presence or absence of leakage in the buried pipeline is determined based on the degree of concentration of the sound pressure data in this frequency portion.

Special table 2003-502678 gazette 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 detection of water leakage cannot be performed.

  On the other hand, the invention according to Patent Document 2 measures the sound pressure in the pipe for a predetermined time, and determines that water leakage has occurred when the sound pressure is concentrated at a constant value.

  Therefore, in a quiet environment with little noise, there is a problem that the sound pressure may be constant even if water leakage does not occur, and accurate determination cannot be made.

  In order to solve such problems, a main object of the present invention is to provide a conduit abnormality determination method capable of determining a conduit abnormality based on a calculated determination value. Another object of the present invention is to provide a method for determining an abnormality of a pipeline that can determine an abnormality of the pipeline at one inspection position.

(1)
A method for determining an abnormality in a pipeline according to one aspect is a determination method for determining an abnormality in a pipeline, wherein vibration data measurement is performed by measuring vibration of a pipeline for a predetermined time at at least one inspection position. A waveform pattern extracting step for extracting a part of the waveform pattern from at least one vibration data obtained in the vibration data measuring step, a waveform pattern obtained in the waveform pattern extracting step, and a vibration data measuring step. A cross-correlation step for obtaining a cross-correlation function with vibration data, and a determination value calculation step for calculating a determination value from the amplitude of the cross-correlation function obtained in the cross-correlation step, and a pipeline based on the calculated determination value It is a thing which judges abnormality of.

  For example, when water leakage occurs in a pipeline, the generation source is the same, and thus a unique waveform pattern derived from water leakage occurs. The waveform pattern is continuously generated in time series. That is, a unique waveform pattern derived from water leakage is measured among vibration data in time series.

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

  Therefore, the value (determination value) calculated from the amplitude of the cross-correlation function is a unique value corresponding to the pipeline environment. As a result, it is possible to determine the abnormality of the pipeline based on the calculated determination value.

(2)
A method for determining an abnormality in a pipeline according to another aspect is a determination method for determining an abnormality in a pipeline, and vibration data measurement that obtains vibration data by measuring the vibration of the pipeline for a predetermined time at one inspection position. A waveform pattern extracting step for extracting a plurality of waveform patterns from one vibration data obtained in the vibration data measuring step, a plurality of waveform patterns obtained in the waveform pattern extracting step, and a vibration data measuring step. A cross-correlation step for obtaining a cross-correlation function with one vibration data, and a determination value calculation step for calculating a determination value from the amplitude of the cross-correlation function obtained in the cross-correlation step, based on the calculated determination value The abnormality of the pipeline is determined 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, a portion of the waveform pattern repeated in the vibration data (for example, a unique waveform portion due to water leakage) has a large correlation value.

  Therefore, the value (determination value) calculated from the amplitude of the cross-correlation function is a unique value corresponding to the pipeline environment. As a result, it is possible to determine the abnormality of the pipeline based on the calculated determination value. That is, it is possible to determine the abnormality of the pipeline at one inspection position.

(3)
A method for determining an abnormality in a pipeline according to a third aspect of the invention is a determination method for determining an abnormality in a pipeline according to one aspect or another aspect, wherein the determination value calculation step includes a cross-correlation obtained in the cross-correlation step. A determination value that relatively indicates 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 pipeline.

  “Relatively indicating 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 thereof. It also includes dividing the average value of the maximum values by the average value of the positive part of the cross-correlation function.

  A value (determination value) that relatively indicates the magnitude of the correlation from the amplitude of the cross-correlation function is a specific value corresponding to the environment of the pipeline. Then, determination values under various environments are calculated in advance (predetermined determination values). Then, the determination value of the pipeline to be examined is calculated.

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

(4)
A method for determining an abnormality in a pipeline according to a fourth invention is a determination method for determining an abnormality in a pipeline according to the third invention, wherein the calculated determination value is an upper limit of a predetermined range of a predetermined determination value. When the value is exceeded, it is determined that the pipeline vibrates due to mechanical vibration.

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

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

  Since the source of leakage is the same, there is a unique waveform pattern. And the water leak has generate | occur | produced continuously. As a result, the correlation value between the waveform pattern and the vibration data increases. That is, although the value is lower than the mechanical vibration, the calculated determination value is increased. Therefore, when it is within the predetermined range of the predetermined determination value, it can be determined that water leakage has occurred.

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 the vibration data and waveform pattern in one Embodiment of this invention. The judgment table arranged in order of the judgment value in one embodiment of the present invention. The judgment table arranged in order of the judgment value in one embodiment of the present invention.

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

  FIG. 1 is a schematic diagram in which a piezoelectric sensor 200 that is a vibration sensor installed in a pipe 100 that is a pipe line detects vibration of the pipe 100. Vibration data detected by the piezoelectric sensor 200 is sent to the control device 300. Note that the transmission method of vibration data from the piezoelectric sensor 200 to the control device 300 may be either a wired or wireless transmission method.

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

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

  Next, the control device 300 stores the vibration data obtained from the piezoelectric sensor 200 in the storage unit 310. Then, the control device 300 extracts a plurality of waveform patterns from the stored vibration data (step S12). Note that the waveform pattern may be extracted while the operator watches the vibration data on the monitor 400.

  The waveform pattern to be extracted is extracted in an arbitrary time zone, but preferably has an average sound pressure level that does not include obvious noise.

  The extracted waveform pattern includes a waveform pattern unique to water leakage if, for example, water leakage occurs. However, there are many cases in which an operator cannot make a judgment by looking at vibration data. Therefore, a cross-correlation function between the waveform pattern and vibration data is obtained.

  Specifically, the control device 300 obtains a cross-correlation function between the vibration data and each waveform pattern at the calculation unit 320 (step S13). The 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 has occurred, the waveform pattern unique to water leakage is included in both the extracted waveform pattern and vibration data. Therefore, if a cross-correlation function between the extracted waveform pattern and vibration data is obtained, the correlation value increases.

  On the other hand, when mechanical vibration is occurring, the mechanical vibration is a unique waveform pattern. The mechanical vibration waveform pattern is included in both the extracted waveform pattern and the vibration data. Furthermore, the regularity is high compared with the case of water leakage. Therefore, if the cross-correlation function between the extracted waveform pattern and the vibration data is obtained, the correlation value becomes larger than that 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, a cross-correlation function is obtained at a large number of points along the time series of the extracted waveform pattern and vibration data. Then, each maximum value is 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 certain value as the calculated number increases. In some cases, the average value of the maximum values 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.

  Thus, by calculating a so-called determination value, it becomes easier to compare with other environments.

  Next, the determined determination value is compared with a predetermined determination value to determine whether or not water leakage has occurred in the pipe 100.

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

  In summary, it is as follows. When there is water leakage, the source is the same, unlike noise. Therefore, there is a unique waveform pattern corresponding to the water leakage. In the case of water leakage, the waveform pattern is continuously generated.

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

  In addition, since water leakage occurs continuously, when this 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 sound generated by the pump or the motor has a strong regularity of the waveform as compared with the vibration of water leakage. As a result, the value of the cross-correlation function is higher than that in the case of water leakage. Therefore, it is possible to distinguish between a case of water leakage and a case of mechanical vibration.

<Flowchart 2 of determination method of abnormality of pipeline>
FIG. 3 is a flowchart of a method for determining an abnormality in a pipeline according to another aspect of the present invention. The same parts as those in the flowchart 1 described above are omitted.

  At one inspection position, the piezoelectric sensor 200 measures the vibration of the pipe 100 for a predetermined time 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 stores one vibration data obtained from the piezoelectric sensor 200 in the storage unit 310. Then, the control device 300 extracts a plurality of waveform patterns from one stored vibration data (step S22).

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

  That is, a cross-correlation function between a plurality of waveform patterns in an arbitrary time zone extracted from one vibration data and vibration data before extraction is obtained. For example, if water leaks in the pipeline, the waveform pattern of water leakage is included in both the extracted waveform pattern and the vibration data. For this reason, the correlation value increases in the portion of the vibration data where there is a waveform pattern of water leakage.

  Similarly, in the case of mechanical vibration, the waveform pattern of water leakage is included in both the extracted waveform pattern and the vibration data. For this reason, the correlation value increases in the portion of the vibration data where there is a mechanical vibration waveform pattern. In the case of mechanical vibration, since the regularity is higher than that of water leakage, the correlation value is larger than that of water leakage.

  Next, the computing unit 320 calculates a determination value from the amplitude of the cross-correlation function obtained in step S23 (step S24). The method for obtaining the determination value is as described above.

  From these facts, it is possible to determine the abnormality of the pipeline 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 (A, B, C) of arbitrary 0.1 second waveforms (waveform patterns) are extracted from the 50 second waveforms.

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

  This operation is repeated in the same manner to obtain cross-correlation functions from n1 to n million. If n1 is the first, nk indicates the kth. This operation is similarly performed for the waveform pattern B and the waveform pattern C in addition to the waveform pattern A.

  That is, waveform pattern A obtains 1 million cross-correlation functions. Similarly, 1 million cross-correlation functions are obtained for 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 for all the calculated 3 million cross-correlation functions. Then, the average value of the maximum values of the 3 million cross-correlation functions is calculated. Next, of the 3 million cross-correlation functions, the average value of the portion where the cross-correlation function is positive 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 formula.
Judgment value = [average value of the maximum value of the cross-correlation function] / [average value of the portion where the 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, a range of a portion where water leakage occurs is defined as a predetermined range P1. The predetermined range P1 includes an upper limit value H1 and a lower limit value L1.

  In FIG. 6, the upper limit value H1 of the predetermined range P1 is 0.25, and the lower limit value L1 is 0.10. The determination value higher than the upper limit value H1 is mechanical sound such as pump sound, that is, mechanical vibration. Further, a determination value having a value lower than the lower limit value L1 is determined as having no water leakage.

  Specifically, when the determination value is 0.10 or less, it is determined that water leakage has not occurred. If the determination value is greater than 0.10 and less than or equal to 0.25, it is determined that water leakage has occurred. When the determination value exceeds 0.25, it is determined as mechanical sound, that is, mechanical vibration.

  For example, it is assumed that the determination value is calculated according to the flowcharts shown in FIGS. 2 and 3 in the pipe 100 where it is not known whether or not water leakage has occurred. The calculation method of the determination value follows the above equation (1).

  The determination value is assumed to be 0.15, for example. In this case, since 0.15 is 0.10 exceeding 0.25 and below, 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 or not water leakage has occurred on the spot.

  As a specific example, a piezoelectric sensor was installed on the valve of the water pipe VP50, and vibration was measured. At this time, since the judgment value was 0.21, when the periphery of the valve was drilled by boring, water leakage was actually generated. “VP” means a hard vinyl chloride pipe.

  Next, the piezoelectric sensor was installed on the valve | bulb of another water pipe VP50, and the vibration was measured. At this time, since the judgment value was 0.44, when the periphery was examined, this was the pump sound of the septic tank.

  A piezoelectric sensor was installed on the valve of the water pipe DCIP100, and vibration was measured. At this time, since the judgment value was 0.24, when the periphery of the valve was dug by boring, water leakage actually occurred. “DCIP” refers to a ductile cast iron pipe.

<Example 2>
Parts similar to those in the first embodiment are omitted. In Example 2, the maximum value of the cross-correlation function is calculated for all of the calculated 3 million cross-correlation functions. Then, the average value of the maximum values of the 3 million cross-correlation functions is calculated.

The judgment value is calculated by the following formula.
Judgment value = average of the maximum value of the cross-correlation function (2)

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

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

  Specifically, when the determination value is 0.40 or less, it is determined that water leakage has not occurred. If the determination value is greater than 0.40 and less than or equal to 0.70, it is determined that water leakage has occurred. When the determination value exceeds 0.70, it is determined as mechanical sound, that is, mechanical vibration.

  For example, it is assumed that the determination value is calculated according to the flowcharts shown in FIGS. 2 and 3 in the pipe 100 where it is not known whether or not water leakage has occurred. The calculation method of the determination value follows the above equation (2). If the determination value is 0.45, for example, it is not less than 0.40 and not more than 0.70, which corresponds to 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 the water pipe VP100, and vibration was measured. At this time, the judgment value was 0.61, so when the bore around the valve was drilled, water leakage actually occurred.

  Next, the piezoelectric sensor was installed on the valve | bulb of another water pipe VP50, and the vibration was measured. At this time, since the judgment value became 0.88, when the periphery was investigated, there was a vending machine on the pipeline, which was vibrating.

  A piezoelectric sensor was installed on the valve of the water pipe DCIP100, and vibration was measured. At this time, since the judgment value became 0.64, when the periphery of the valve was dug by boring, water leakage actually occurred.

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

  Further, by comparing the calculated determination value with a predetermined determination value, it is possible to know which value of the predetermined determination value corresponds to the calculated determination value. That is, it is possible to determine whether or not water leakage has occurred depending on which value in the first determination table or the second determination table is near the calculated determination value.

  Further, when the calculated determination value exceeds the upper limits H1 and H2 of the predetermined ranges P1 and P2 of the predetermined determination value, it can be determined that the pipeline 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.

  Moreover, when the calculated determination value is within the predetermined ranges P1 and P2 of the predetermined determination value, 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 value H is the “upper limit value”. The lower limit L corresponds to the “lower limit value”.

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

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

  A preferred embodiment of the present invention is as described above, but the present invention is not limited thereto. By combining with an existing determination method such as the degree of concentration of sound pressure data, it is possible to determine abnormality from a plurality of indices. It will be appreciated that various other embodiments may be made without departing from the spirit of the invention. Furthermore, in this embodiment, although the effect | action and effect by the structure of this invention are described, these effect | actions and effects are examples and do not limit this invention.

100 piping (pipe)
200 Piezoelectric sensor (vibration sensor)
300 Control Device 310 Storage Unit 320 Operation Unit 400 Monitor 500 First Determination Table 600 Second Determination Table

Claims (5)

A determination method for determining an abnormality in a pipeline,
A vibration data measurement step for obtaining vibration data by measuring vibrations of a pipe line for a predetermined time at at least one inspection position;
A waveform pattern extracting step of extracting a part of the waveform pattern from at least one of the vibration data obtained in the vibration data measuring step;
A cross-correlation step for obtaining a cross-correlation function between the waveform pattern obtained in the waveform pattern extraction step and the 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,
An abnormality determination method for a pipeline, wherein an abnormality of the pipeline is determined based on the calculated determination value. A determination method for determining an abnormality in a pipeline,
A vibration data measurement process for obtaining vibration data by measuring the vibration of a pipe for a predetermined time at one inspection position;
A waveform pattern extraction step of extracting a plurality of waveform patterns from one vibration data obtained in the vibration data measurement step;
A cross-correlation step for obtaining a cross-correlation function between the plurality of waveform patterns obtained in the waveform pattern extraction step and 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,
A method for determining an abnormality of a pipeline, wherein an abnormality of the pipeline is determined at one inspection position based on the calculated determination value. The determination value calculation step calculates a determination value relatively indicating the magnitude of the correlation from the amplitude of the cross-correlation function obtained in the cross-correlation step,
The pipeline abnormality determination method according to claim 1 or 2, wherein the calculated determination value is compared with a predetermined determination value to determine abnormal vibration of the pipeline.   The pipe line abnormality determination method according to claim 3, wherein when the calculated determination value exceeds an upper limit value of a predetermined range of a predetermined determination value, it is determined that the pipe vibrates due to mechanical vibration. . The pipe line abnormality determination method according to claim 3 or 4, wherein when the calculated determination value is within the predetermined range, it is determined that water leaks in the pipe line.

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