JP2017198576A - Leak testing device and testing method, for underground tanks - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leak testing device and a leak testing method that can accurately determine the presence or absence of any leak from liquid phase parts of underground tanks.SOLUTION: A leak testing device for underground tanks comprises: a vibration sound detector 2 that measures vibration sounds in the liquid phase part of an underground tank 1 for a desired period of time in a state of not reducing the pressure to a required low level necessary for leak testing and also measures vibration sounds for a desired period of time in the liquid phase part of the underground tank in a state of reducing the pressure to the required low level necessary for leak testing; a memory 8 that stores each of the measured vibration sounds as dark noise data and tested leak sound data; and a calculation memory processor 4 having a determining unit 9d that determines the presence or absence of any leak according to whether or not the result of comparison satisfies desired conditions by comparing the stored dark noise data and tested leak sound data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a leakage inspection apparatus and an inspection method for a liquid phase part such as a tank for storing dangerous materials buried underground.

  Underground tanks that store hazardous materials such as gasoline, light oil, and kerosene are required by law to check for leaks once a year in principle. Since tanks to be inspected for leaks store dangerous materials, it is common to inspect the tank without emptying it. The gas phase part above the liquid level in the tank and the underground It is necessary to inspect each liquid phase part of the liquid part below the liquid level in the tank.

  These inspections are stipulated in fire-fighting-related laws and regulations, and specific methods and criteria for gas phase inspection are shown, but specific methods are specified for liquid phase inspection. So, for example, as a method for inspecting the liquid phase part, the tank is sealed, the gas phase part above the liquid level is depressurized, and bubbles are sucked into the liquid phase part in the tank from outside the tank by depressurization There is an inspection method for detecting a vibration sound generated by a microphone or the like inserted in a liquid phase portion.

  However, in the case of an underground tank at a gas station installed along a road, for example, vibration due to a vehicle that randomly passes through the road is measured as noise during measurement. The background-specific background noise other than the sound is mixed during measurement, and the leaked sound cannot be determined.

  Therefore, for example, in the inspection methods of Patent Document 1 and Patent Document 2, frequency analysis of vibration sound obtained by measurement is performed on the basis of the frequency of leaked sound collected in advance, and the frequency corresponding to the reference leaked sound Only the components were extracted to determine the presence or absence of leakage.

Japanese Patent No. 4271006 Japanese Patent No. 4206498

  However, in the conventional inspection method, it is difficult to collect all leaked sounds with different frequencies depending on the shape of the leak port, the size of the leak port, the position of the leak port, etc. Only detected leaks can be detected.

  In addition, when the noise includes a frequency component that overlaps with the reference leakage sound, there is a problem in that noise having a frequency close to the reference leakage sound cannot be removed, resulting in erroneous determination.

  The present invention is intended to solve the above problems.

  In order to achieve the above-mentioned object, the underground tank leakage inspection apparatus of the present invention is a liquid phase part in the underground tank in a state where the underground tank is not depressurized to a desired reduced pressure value necessary for performing the leakage inspection. A vibration sound detector for measuring the vibration sound of a desired time, and the liquid phase part in the underground tank in a state where the inside of the underground tank is depressurized to a desired reduced pressure value necessary for leak inspection A vibration sound detector for measuring the vibration sound for a desired time, a storage unit for storing the measured vibration sounds as background noise data and leakage inspection sound data, and the stored background noise data, respectively. It is characterized by comprising an arithmetic storage processing device having a determination unit that compares the leakage inspection sound data and determines whether or not there is a leakage based on whether or not the comparison result satisfies a desired condition.

  Further, the background noise data stored in the storage unit is divided every desired time, and the background noise data having the maximum vibration sound is extracted from the background noise data in each partition, The extracted background noise data is stored as background noise data in the storage unit, and the leak test time sound data stored in the storage unit is divided at each desired time, and at the time of a leak test in each partition Extracting sound data at the time of leakage inspection with the maximum vibration sound from the sound data, and extracting the extracted sound data at time of leakage inspection as sound data at time of leakage inspection in the storage unit Is further provided in the arithmetic storage processing device.

  Further, when the background noise data stored in the storage unit is arranged in ascending / descending order based on the magnitude of the vibration sound, the background noise data located in the intermediate range is extracted, and the extracted background noise data is used for determination. As the background noise data to be used, when the leak test is stored in the storage unit and the leak test sound data stored in the storage unit are arranged in the ascending / descending order based on the magnitude of the vibration sound, the leak test is performed in the middle range The arithmetic storage processing device is further provided with a determination data extraction unit that extracts sound data and stores the extracted leakage inspection sound in the storage unit as leakage inspection sound data used for determination. And

  Further, the vibration sound detection device is characterized by comprising a listening pipe whose tip is immersed in a liquid phase part, and a vibration detection sensor provided on the listening pipe.

  In the underground tank leakage inspection method of the present invention, the vibration of the liquid phase portion in the underground tank is not reduced to a desired reduced pressure value necessary for performing the leakage inspection in the underground tank. Necessary for measuring the vibration sound for a desired time, storing the measured vibration sound as background noise data in a storage unit provided in the arithmetic storage processing device, and conducting a leak inspection in the underground tank In a state where the pressure is reduced to a desired reduced pressure value, the vibration sound of the liquid phase portion in the underground tank is measured by a vibration sound detection device for a desired time, and the measured vibration sound is stored as sound data at the time of leakage inspection. It consists of the 1st process memorize | stored in a part.

  In addition, the basic data extraction unit provided in the arithmetic storage processing device divides the background noise data stored in the storage unit in the first step every desired time, and among the background noise data in each partition, The background noise data with the maximum vibration noise is extracted, and the extracted background noise data is stored as background noise data in the storage unit and stored in the storage unit in the first step. The leak test sound data is divided at every desired time, and from among the leak test sound data within each partition, the leak test sound data with the maximum vibration sound is extracted and extracted. The leak test time sound data is further stored in the storage unit as leak test time sound data.

  The background noise data stored in the storage unit in the first step or the second step is arranged in ascending / descending order based on the magnitude of vibration sound by the determination data extraction unit provided in the arithmetic storage processing device. Sometimes, the background noise data located in the intermediate range is extracted, and the extracted background noise data is stored in the storage unit as background noise data used for determination, and the storage unit is used in the first step or the second step. When the leak test sound data stored in is arranged in ascending / descending order based on the magnitude of vibration sound, the leak test sound data located in the middle range is extracted, and the leak test sound data extracted is determined. It further has the 3rd process memorized as the sound data at the time of leak inspection used for the above-mentioned storage part.

  The determination unit provided in the arithmetic storage processing device compares the background noise data stored in the storage unit with the sound data at the time of leakage inspection, and leaks depending on whether or not the comparison result satisfies a desired condition. The method further includes a fourth step of determining the presence or absence.

  Further, the background noise data stored in the storage unit of the fourth step and the sound data at the time of leakage inspection are compared, and whether or not the comparison result satisfies a desired condition is the background noise. The ratio between the average value of the data and the average value of the sound data at the time of leakage inspection is within a desired range.

  The ratio between the average value of the background noise data and the average value of the sound data at the time of leakage inspection may be a logarithmic ratio.

  According to the present invention, a complicated process of collecting a large number of reference sounds each having a different frequency depending on the shape and size of the leak port, the position of the leak port, and the like is unnecessary, and further overlaps with the leak sound included in the background noise. Since it is not affected by the frequency component, it is possible to provide a leakage inspection apparatus that can avoid erroneous determination due to noise having a frequency close to the leakage sound.

It is the schematic of the leak inspection apparatus of the underground tank of this invention. It is explanatory drawing of the signal converter of the leak inspection apparatus of the underground tank of this invention. It is explanatory drawing of the arithmetic storage processing apparatus of the leakage inspection apparatus of the underground tank of this invention. It is a graph of the A / D conversion value data sampled by the sampling process part of the leakage inspection apparatus of the underground tank of this invention. It is a graph of the background noise data extracted by the basic data extraction part of the leakage inspection apparatus of the underground tank of this invention. It is a graph of the background noise data extracted by the basic data extraction part of the leakage inspection apparatus of the underground tank of this invention, and the measurement sound data at the time of a leakage inspection. It is the graph which rearranged the background noise data extracted by the extraction part as basic data of the leakage inspection apparatus of the underground tank of this invention, and the sound data at the time of leakage inspection in ascending and descending order. It is a determination table | surface determined by the determination part of the leak inspection apparatus of the underground tank of this invention.

  The example of the form for carrying out the present invention is shown below.

  A first embodiment of the underground tank leakage inspection apparatus and leakage inspection method of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the leakage inspection apparatus for a liquid phase part of an underground tank of the present invention includes a liquid phase part L (including an underground tank part in contact with the liquid phase part) of the underground tank 1 buried underground. A vibration sound detection device 2 that detects vibration sound, a signal conversion device 3 that converts a signal detected by the vibration sound detection device 2 into a signal that can be processed by an arithmetic storage processing device such as a personal computer, and the signal conversion device 3 It comprises an arithmetic storage processing device 4 such as a personal computer for calculating / storing the converted signal.

  G represents a gas phase portion of the underground tank 1. In addition, 5 indicates an opening such as a metering port formed in the ceiling portion 1a of the underground tank 1, 10 indicates a leakage port formed in the liquid phase portion of the underground tank, and 11 Indicates a bubble leaking from the leak port.

  The vibration sound detection device 2 includes a sound pipe 6 and a vibration detection sensor 7 such as a piezoelectric element that detects vibration or acceleration from the sound pipe 6.

  The listening pipe 6 is suspended from the outside of the underground tank 1 into the underground tank 1 through the opening 5, and the lower end of the listening pipe 6 is connected to the liquid phase portion L of the underground tank 1. It is immersed and provided in close contact with the bottom surface 1b of the underground tank 1, and the sound pipe 6 detects the vibration sound of the liquid phase part (including the underground tank part in contact with the liquid phase part) in the underground tank. Configured as follows.

The opening 5 is hermetically closed, and the underground tank 1 is hermetically sealed.

  The vibration detection sensor 7 is fixed to the upper end of the listening pipe 6.

  Further, as shown in FIG. 2, the signal conversion device 3 includes an amplification unit 3a that amplifies the voltage detected by the vibration detection sensor 7 of the vibration sound detection device 2, a voltage change amplified by the amplification unit 3a, and the like. The A / D conversion unit 3b that converts the analog signal into a digital signal and the communication circuit unit 3c that communicates the converted digital signal (A / D conversion value) to the arithmetic storage processing device 4.

  The calculation storage processing device 4 includes a storage unit 8 and a calculation unit 9. The storage unit 8 stores A / D conversion values and the like from the communication circuit unit 3c, and the calculation unit 9 Performs various processes, and includes, for example, a sampling processing unit 9a, a basic data extraction unit 9b, a determination data extraction unit 9c, and a determination unit 9d.

  Reference numeral 4a denotes a monitor of the arithmetic storage processing device 4.

  The sampling processing unit 9a samples the A / D conversion value data stored in the storage unit 8 at a desired sampling rate (sampling frequency), and stores the sampled A / D conversion value data in the storage unit 8. Process to memorize.

  Further, the basic data extraction unit 9b divides the sampled A / D conversion values at regular unit times (for example, every 1 second), and the A / D within each division (within each unit time). A maximum A / D conversion value is extracted from the D conversion values, and each value is stored in the storage unit 8 as section maximum A / D conversion value data.

  Further, the determination data extraction unit 9c rearranges the section maximum A / D conversion value data in ascending order (or descending order), and from the rearranged data, for example, suddenly due to vehicle passage or the like. This is considered as vibration data that has been attenuated due to the action of background noise or vibration in the opposite phase to the sound at the time of leakage inspection, while excluding those that have a large range of maximum A / D conversion values that may contain significant vibrations. Processing that excludes the range having a small section maximum A / D conversion value, extracts only the A / D conversion value data in the intermediate range of the data, and stores the extracted data in the storage unit 8 Do.

  The determination unit 9d compares A / D conversion values of the stored determination data, and performs a process of determining whether there is a leak depending on whether the comparison result satisfies a desired condition.

  Next, a leakage inspection method using the underground tank leakage inspection apparatus of the present invention and the effects thereof will be described.

(Installation of leak inspection equipment)

  As shown in FIG. 1, a leak inspection device is installed in the underground tank 1.

  That is, first, the listening pipe 6 is suspended through the opening 5 of the underground tank 1, the lower end of the listening pipe 6 is immersed in the liquid phase portion L of the underground tank 1, and the underground tank 1 Is attached to the underground tank 1 in close contact with the bottom surface 1b.

  Further, the opening 5 is hermetically closed, and the inside of the underground tank 1 is hermetically sealed.

  Further, the vibration detection sensor 7 is attached to the upper part of the listening pipe 6, the vibration detection sensor 7 and the signal conversion device 3 are connected, and the signal conversion device 3 and the arithmetic storage processing device 4 are connected. To do.

  As a result, a leak inspection device is installed in the underground tank 1, and then the background noise is measured and the sound during the leak inspection is measured.

(Measurement of background noise)

  First, background noise is measured.

  The background noise is vibration sound that does not include leakage sound when the inside of the underground tank is not depressurized, and the vibration sound is mainly composed of vibration due to the installation environment that is constantly generated inside and outside the underground tank 1, and It is a sound that sudden noise such as traffic of vehicles is sometimes added.

  Specifically, the background noise 1 is measured by detecting the vibration from the sound pipe 6 by the vibration detection sensor 7 for a desired measurement time, for example, 180 seconds without decompressing the underground tank 1.

  The state where the pressure is not reduced is a state where the pressure in the underground tank is such that air outside the tank is not sucked into the tank even when the liquid phase portion of the underground tank has a leakage port ( (A state in which the pressure is not reduced to a desired reduced pressure value necessary for the generation of the leaking sound).

  Then, an analog signal such as voltage fluctuation output from the vibration detection sensor 7 is amplified by the signal conversion device 3, converted into a digital signal, read into the arithmetic storage processing device 4, and the arithmetic storage processing The sampling processing unit 9a of the calculation unit 9 of the apparatus 4 performs sampling at a desired sampling rate (sampling frequency), and the sampled A / D conversion value data is stored in the storage unit 8 as background noise data.

  The sampling rate of the sampling processing unit 9a is set to a frequency sufficiently higher than the frequency band of the vibration sound so that the vibration sound can be reproduced as waveform data.

  FIG. 4 is a schematic diagram in which each sampled A / D conversion value data is connected to form a waveform. The horizontal axis represents time, the vertical axis represents voltage A / D converted values, an oscilloscope, etc. You can see it.

(Measurement of sound during leak inspection)

  Next, the sound during leakage inspection is measured. Note that the sound at the time of leakage inspection may be measured before the background noise is measured.

  The specific measurement of sound during a leak test is as follows. First, the gas phase G of the underground tank 1 can suck air outside the underground tank even when it is assumed that there is a leak opening at the bottom of the underground tank 1 The pressure in the gas phase part G is reduced to a value -3 kPa lower than the pressure at the bottom of the tank due to the liquid level in the tank and the water level outside the tank, for example. Reduce the pressure so that

  Then, in the state where the underground tank 1 is decompressed, the vibration detection sensor detects vibration from the listening pipe 6 during the same measurement time (180 seconds) as the measurement of the background noise, similarly to the measurement of the background noise. 7, and an analog signal such as a voltage fluctuation output by the vibration detection sensor 7 is amplified by the signal converter 3, converted into a digital signal, and read into the arithmetic storage processor 4. The sampling processing unit 9a of the arithmetic storage processing device 4 performs sampling at a desired sampling rate (sampling frequency), and the sampled A / D conversion value data is stored in the storage unit 8 as leakage inspection time sound data.

  When the underground tank 1 leaks, the vibration of the leak inspection sound is a vibration in which a bubble sound due to leakage is regularly added to the vibration of the background noise, and the underground tank 1 If there is no leakage, the vibration is the same as that in the background noise.

  Next, the background noise data and the sound data at the time of leakage inspection are compared to determine the presence or absence of leakage.

  However, since each of the data includes sudden noise and the like, before the comparison of the data, for extracting the data for determination, which excludes the noise and the like from each of the data, respectively. Perform processing.

(Judgment data extraction process)

  Since it takes a processing time to extract determination data based on all data of the sampled A / D conversion value data, first, it is necessary to extract from the sampled A / D conversion value data. Basic data is extracted, and determination data is extracted based on the extracted basic data.

  Specifically, the basic data extraction work is performed by the basic data extraction unit 9b of the arithmetic storage processing device 4 and the stored background noise data measured for a desired measurement time (180 seconds), that is, as shown in FIG. In addition, the sampled A / D conversion value is divided every fixed unit time (for example, divided every second), and the maximum A among the A / D conversion values within each division (within each unit time). / D conversion values are extracted (for example, A / D conversion values surrounded by circles in FIG. 4), and these values are used as background noise basic data (background noise maximum A / D conversion value data). The data is stored in the storage unit 8.

  In FIG. 5, the measurement time of the background noise data of 180 seconds is divided every second, the maximum value of each section is extracted, and the extracted 180 section noise maximum A / D conversion value data of the background noise is dotted. Is a graph.

  Further, the stored sound data at the time of leakage inspection measured for a desired measurement time (180 seconds), that is, the sampled A / D conversion value is also converted by the basic data extraction unit 9b of the arithmetic storage processing device 4 into the dark data. As with the noise data, it is divided at the same unit time (for example, 1 second) as above, and the maximum A / D conversion value is extracted from the A / D conversion values within each division (within each unit time). Such values are stored in the storage unit 8 as section maximum A / D conversion value data of the sound at the time of leakage inspection.

  FIG. 6 is a graph showing the background maximum A / D conversion value data of the background noise (dotted line) and a graph showing the section maximum A / D conversion value data of the sound at the time of leakage inspection (solid line). Are superimposed and displayed.

  Then, the extracted maximum value of each section is a characteristic measurement value that most clearly captures the vibration state of each section.

  Next, a determination data extraction operation is performed.

  Sudden vibration must be excluded as noise. Therefore, first, the background noise maximum section A / D conversion value data and the leak maximum sound section A / D conversion value data are obtained by the determination data extraction unit 9c of the arithmetic storage processing device 4. Sorted in ascending order (or descending order), respectively, and from the sorted data, for example, a value with a large section maximum A / D conversion value that may include sudden vibration due to vehicle passing etc. In addition, the data having a small section maximum A / D conversion value, which is considered to be vibration data that is attenuated by the action of the vibration having the opposite phase to the background noise or the sound at the time of leakage inspection, is excluded. Only the / D conversion value data is extracted, and the extracted data is stored in the storage unit 8 as leakage determination data for background noise and leakage determination data for leakage inspection sound, respectively.

  Note that FIG. 7 shows the section maximum A / D conversion value data at the time of background noise and the section maximum A / D of the sound at the time of leakage inspection in order to remove abnormally large vibration and abnormally small vibration unnecessary as noise. FIG. 5 is a graph in which conversion value data is rearranged in descending order, and the rearranged maximum background noise A / D conversion value data of the background noise and the rearranged maximum A / D conversion of leakage inspection sound. The portion obtained by removing the data of the abnormally large area and the data of the abnormally small area that are noises, that is, the A / D conversion value data of the intermediate range from the value data, respectively, is used as the leakage determination data. .

  As the intermediate range data used as the determination data, for example, out of 180 A / D conversion value data rearranged in ascending / descending order, the tenth data before and after the middle 90th data, That is, the 21st data from the 80th data to the 100th data are used as determination data.

(Leakage determination process)

  Next, the A / D conversion value of the determination data in the background noise is compared with the A / D conversion value of the determination data in the leakage inspection sound by the determination unit 9d of the arithmetic storage processing device 4, and this comparison is performed. Whether or not there is a leak is determined based on whether or not the result satisfies a desired condition.

  Specifically, for example, by the determination unit 9d of the arithmetic and storage processing device 4, the average value of the A / D conversion values of the obtained determination data in the background noise and the A of the determination data in the leakage inspection sound Each of the average values of the D / D conversion values is obtained, and the ratio of the average value of the judgment data of the sound at the time of leakage inspection to the average value of the judgment data of the background noise is obtained, and the ratio is, for example, a desired value If it is within the range, it is determined that there is no leakage, and if it is out of the range, it is determined that there is leakage.

  As described above, the difference in determination due to the difference in background noise that differs for each underground tank can be removed by obtaining the average value ratio.

  Table 1 shows the 80th to 100th data of the rearranged background noise maximum A / D conversion value data and the rearranged leak inspection sound maximum A / D conversion value data. The average value is 459 for the former and 1700 for the latter.

  Moreover, as a formula for obtaining the ratio, there is, for example, the number 1 that represents the ratio of the average values as a logarithmic ratio.

  Further, as a determination as to whether or not the ratio D is within a desired range, for example, there is a determination table as shown in FIG. 8, and leakage is obtained by classifying the obtained ratio D by the determination table. It is possible to determine whether or not there is any.

  In the present invention, noise is not identified by frequency, but is performed by the magnitude of vibration, and the obtained data is rearranged in ascending / descending order, and the abnormally loud vibration sound stored as noise and By excluding abnormally low vibration noise, it is possible to compare background noise and noise at the time of leak inspection excluding sudden noise, etc., so that the presence or absence of leakage in the liquid phase part of the underground tank can be accurately captured regardless of frequency. Will be able to.

  The underground tank leakage inspection apparatus and inspection method of the present invention can be used for an underground tank having a liquid phase portion.

DESCRIPTION OF SYMBOLS 1 Underground tank 1a Ceiling part 1b Bottom face 2 Vibration sound detection apparatus 3 Signal conversion apparatus 3a Amplification part 3b A / D conversion part 3c Communication circuit part 4 Arithmetic storage processing apparatus 4a Monitor 5 Opening part 6 Hearing pipe 7 Vibration detection sensor 8 Storage part 9 Calculation Unit 9a Sampling Processing Unit 9b Basic Data Value Extraction Unit 9c Determination Data Extraction Unit 9d Determination Unit 10 Leakage Port 11 Bubble

Claims (10)

To measure the vibration sound of the liquid phase in the underground tank for a desired time without depressurizing the underground tank to the desired depressurization value necessary for leak inspection. In a state where the pressure is reduced to a desired desired reduced pressure value, a vibration sound detection device that measures the vibration sound of the liquid phase portion in the underground tank for a desired time;
Each of the measured vibration sounds is stored as background noise data and leakage inspection sound data, and the storage unit stores the stored background noise data and leakage inspection sound data, and the comparison result is desired. An underground tank leakage inspection device comprising: an arithmetic storage processing device having a determination unit that determines whether there is leakage depending on whether or not the above condition is satisfied. The background noise data stored in the storage unit is divided every desired time, and among the background noise data in each partition, the background noise data with the maximum vibration sound is extracted and extracted. The background noise data is stored in the storage unit as background noise data,
Leakage inspection sound data stored in the storage unit is divided at each desired time, and among the leakage inspection sound data in each partition, leakage inspection sound data with the maximum vibration sound is obtained. 2. The arithmetic storage processing device according to claim 1, further comprising: a basic data extraction unit that extracts each of the extracted leak test sound data and stores the extracted leak test sound data in the storage unit as leak test sound data. Leak inspection device for underground tanks as described in 1. When the background noise data stored in the storage unit is arranged in ascending / descending order based on the magnitude of vibration sound, the background noise data located in the intermediate range is extracted, and the extracted background noise data is used as background noise data. And storing in the storage unit,
When the leak test sound data stored in the storage unit is arranged in the ascending / descending order based on the magnitude of the vibration sound, the leak test sound data located in the intermediate range is extracted, and the leak check sound data is extracted. The underground tank leakage inspection apparatus according to claim 1, further comprising a determination data extraction unit that is stored in the storage unit as sound data at the time of leakage inspection.   4. The vibration sound detection device according to claim 1, wherein the vibration sound detection device includes a sound pipe whose tip is immersed in a liquid phase portion, and a vibration detection sensor provided on the sound pipe. 5. Underground tank leak inspection device. While the underground tank is not depressurized to the desired depressurization value necessary for the leak inspection, the vibration sound of the liquid phase part in the underground tank is measured for a desired time by the vibration sound detector, and the measurement is performed. The underground tank is stored as a background noise data in a storage unit provided in the arithmetic storage processing device, and the underground tank is decompressed to a desired decompression value necessary for performing a leak test. A first step of measuring the vibration sound of the liquid phase portion in the storage unit for a desired time, measured by the vibration sound detection device, and storing the measured vibration sound as sound data at the time of leakage inspection,
An underground tank leakage inspection method characterized by comprising: By the basic data extraction unit provided in the arithmetic storage processing device,
The background noise data stored in the storage unit in the first step is divided every desired time, and the background noise data having the maximum vibration sound is extracted from the background noise data in each partition. The extracted background noise data is stored in the storage unit as background noise data,
Leakage inspection sound data stored in the storage unit in the first step is divided every desired time, and among the leakage inspection sound data in each division, the leakage with the largest vibration sound level 6. The underground according to claim 5, further comprising a second step of extracting the inspection sound data and storing the extracted leakage inspection sound data in the storage unit as leakage inspection sound data. Tank leak inspection method. By the data extraction unit for determination provided in the arithmetic storage processing device,
When the background noise data stored in the storage unit in the first step or the second step is arranged in ascending / descending order based on the magnitude of vibration sound, the background noise data located in the intermediate range is extracted and extracted. The background noise data is stored in the storage unit as background noise data,
When the leak test sound data stored in the storage unit in the first step or the second step is arranged in ascending / descending order based on the magnitude of vibration sound, the leak test sound data located in the intermediate range is extracted. The underground tank leakage inspection according to claim 5 or 6, further comprising a third step of storing the extracted leakage inspection sound data in the storage unit as leakage inspection sound data. Method. By the determination unit provided in the arithmetic storage processing device,
A fourth step of comparing the background noise data stored in the storage unit and the sound data at the time of leakage inspection, and determining whether there is leakage based on whether or not the comparison result satisfies a desired condition; The underground tank leakage inspection method according to any one of claims 5 to 7. Comparing the background noise data stored in the storage unit of the fourth step and the sound data at the time of leakage inspection, whether the comparison result satisfies a desired condition,
9. The underground tank leakage inspection according to claim 8, wherein a ratio between an average value of the background noise data and an average value of the sound data at the time of leakage inspection is within a desired range. Method. The underground tank leakage inspection method according to claim 9, wherein a ratio between an average value of the background noise data and an average value of the leakage inspection sound data is a logarithmic ratio.

Images