JP4978870B2 - Leakage pipe inspection method and inspection apparatus - Google Patents

Description

  The present invention relates to a leak pipe inspection method and inspection apparatus suitable for exploring leak points of various pipes from large-diameter pipes to residential gas pipes in agricultural water use facilities.

  Conventionally, a sonic-type pipe leak inspection method is known as means for inspecting leakage of underground pipes such as water pipes and gas pipes (Patent Document 1). This inspection method detects high-frequency sound pressure at two points on a pipe and determines the presence or absence of leakage in comparison with a high-frequency sound pressure as a standard pattern of reference points. This is a method of calculating the leak point from the radio wave time difference. Such means for collating the standard pattern with the high-frequency sound pressure of the measurement sound is known as a pattern recognition method.

  On the other hand, Patent Document 2 describes a water leakage sound identification method using a high-accuracy frequency analysis method as another means for identifying a water leakage sound. In this analysis method, level-to-frequency characteristics are obtained by high-precision frequency analysis, and analysis is performed using moving average characteristics obtained by moving average with a predetermined frequency width.

  Furthermore, as a method for exploring a water leak location outside the building, Patent Document 3 discloses an inspection method for specifying a water leak location by entering ultrasonic waves together with compressed air. According to this inspection method, ultrasonic waves are incident along with compressed air from the water leakage point inside the building, and the ultrasonic waves in the compressed air propagating to the outside of the building through cracks and gaps in the building structure that is the water leakage path are measured. In order to investigate the location of water leakage outside the building.

JP-A-5-87669 Japanese Patent No. 3641817 Japanese Patent Laid-Open No. 2003-65880

  According to the pattern recognition method as disclosed in Patent Document 1, since the amount of water increases as the pipe diameter increases, the difference between the sound pressure or frequency band of the standard pattern and the sound pressure or frequency band of the leaked portion is reduced. It becomes difficult to determine the location and the reference point. Therefore, even if the pipe diameter is small, it is not possible to search for a leak point of a large-diameter pipe in an agricultural irrigation facility or the like. Moreover, since the sound pressure sensor described in Patent Document 1 needs to be in direct contact with the pipe, it is extremely difficult to search for a pipe that is entirely buried in the ground.

  In addition, in the high-accuracy frequency analysis method such as Patent Document 2, when the level-to-frequency characteristic is obtained, a similar data area, an obstacle sound data area, and the like overlap with the leaked sound data area, thereby obtaining an accurate level-to-frequency characteristic. This makes it difficult to identify the leak location.

  Furthermore, in the measurement method as in Patent Document 3, since the ultrasonic wave leaked together with the compressed air is measured, the measurable location is directly the compressed air leaking from the leak location, such as the leak location outside the building. Limited to locations where measurement is possible. Therefore, it is not possible to inspect the leakage of underground pipes such as water pipes and gas pipes.

  Therefore, the present invention was created to solve the above-mentioned problems, and it is possible to easily and accurately detect the leaked portion of the pipe P even at a position away from the pipe P. For example, it is buried in the ground. The purpose of the present invention is to provide a leak pipe inspection method and an inspection apparatus that can accurately detect a leak point of a large diameter pipe.

In order to achieve the above-mentioned object, the first means in the present invention is a leak pipe inspection method for detecting a leak portion of the pipe P, which is compressed by the pressure pump 10 inside the pipe P which is sealed and hollowed in the test section. A compressed air filling process 100 for filling air, a low frequency vibration process 200 for generating a low frequency vibration in the pipe P at a low frequency generated by the low frequency generator 20, and a low frequency in the inspection section to the detector 30. And detecting step 300 for detecting
The low-frequency vibration process 200 applies low-frequency vibration to the compressed air before filling the inside of the pipe P, and fills the inside of the pipe P with the compressed air, thereby generating low-frequency vibration inside the pipe P. Is an inspection method for detecting a low-frequency difference position in the pipe P filled with the gas at a position away from the pipe P.

The second means in the present invention is a leak pipe inspection device for detecting a leaking portion of the pipe P, the pressure pump 10 for filling the inside of the pipe P sealed with the inspection section and filled with compressed air, and the pipe P It consists of a low frequency generator 20 that vibrates the internal compressed air at a low frequency, and a detector 30 that detects the low frequency in the sealed pipe P. The low frequency generator 20 discharges the compressed air from the pressure pump 10. The outlet is connected to the alligator and is configured to give low-frequency vibration to the compressed air before filling the inside of the pipe P. The low-frequency difference position inside the pipe P filled with the compressed air is The inspection apparatus is configured to sense at a position away from the object.

In the third means, the pipe P is a large-diameter water pipe buried in the ground, and the inspection section filled with compressed air by the pressure pump 10 is sealed by a stop cock 40, and the cavity of the pipe P is sealed. Compressed air from the pressure pump 10 is sent into the converted inspection section, and a low frequency is oscillated in the compressed air inside the pipe P by the low frequency generator 20. It is configured to detect the position.

The stop cock 40 of the fourth means includes a support plate 42 whose both end portions are widened via a jack 41 arranged substantially at the center, and a bulge-proof pressure-proof arranged inside the support plate 42. It is comprised with the sealing body 44 made from.

  According to the leak pipe inspection method of the first aspect, a low frequency with a low attenuation factor is generated in the compressed air in the pipe P. And since this low frequency sound pressure is the highest at the leak location, comparing these low frequency waveforms makes it possible to identify the leak location very accurately and easily even at a position away from the pipe P. It can be detected.

Further , according to the low frequency vibration process 200, a standing wave with a low frequency can be generated inside the pipe P without directly connecting the low frequency generator 20 to the pipe P, so that the measurement work can be greatly simplified. it can.

As described in claim 2 , the low frequency generator 20 is connected to the compressed air discharge port of the pressure pump 10 and is configured to give low frequency vibration to the compressed air before filling the pipe P. Therefore , it has become possible to detect the leakage location very easily and accurately.

By using the water stopcock 40 according to claim 3 , it is possible to reliably detect a leak location even with a large-diameter water pipe buried in the ground. And since it can detect correctly in the position away from the piping P, it can detect a leak location cheaply in a short period, without damaging a road surface.

According to the stop cock 40 according to the fourth aspect of the present invention, even when the large-diameter pipe P is filled with compressed air and a low frequency is generated, a sufficient sealing force can be obtained. As a result, the inspection range of the piping P can be set freely.

It is a block diagram which shows the inspection method of this invention. It is the schematic which shows one Example of the test | inspection method of this invention. It is the schematic of the state which measures a low frequency with the inspection method of this invention. It is the schematic of the state which detects a leak position with the inspection method of this invention. It is the schematic which shows a pressure pump and a low frequency generator with the test | inspection apparatus of this invention. It is the schematic which shows the other Example of the test | inspection method of this invention. It is a front view which illustrates the water stop cock in the inspection device of the present invention. It is a longitudinal cross-sectional view which illustrates the support disk of this invention water stop cock. It is a front view which illustrates the support board of this invention water stop cock.

  According to the present invention, it is possible to detect a leak location at a position away from the pipe P very easily and accurately. For example, the leak location of a large-diameter pipe buried in the ground is accurately searched. Realized the purpose of being able to.

  Hereinafter, the present invention will be described based on illustrated examples. The leak pipe inspection method of the present invention is an inspection method for detecting a low frequency fluctuation inside the pipe P filled with compressed air at a position away from the pipe P. The compressed air filling process 100, the low frequency vibration process 200, and the detection The process 300 is a main process (see FIG. 1).

  The compressed air filling process 100 is a process in which the compressed air is filled with the pressure pump 10 inside the piping P that is sealed and sealed in the inspection section. In order to seal the inspection section of the pipe P, the fixed section is usually hollowed by closing the stop valve P1 provided in the pipe P (see FIG. 2). That is, a section in which the pair of stop valves P1 is closed is set as an inspection section, and all the water and gas in the inspection section are discharged and hollowed out. The compressed air generated by the pressure pump 10 is filled into the pipe P using the stop valve P1.

  In the illustrated example, the atmospheric pressure gauge 50 is attached to another stop valve P1 within the inspection section, and the compressed air from the pressure pump 10 is filled into the pipe P through the atmospheric pressure gauge 50 (FIG. 2). Further, when the stop valve P1 is not attached to the pipe P, it is also possible to attach a sealing plug (not shown) having a compressed air filling port to the pipe P and fill the compressed air from the sealing plug. is there. In FIG. 2, reference numeral 51 denotes a pipe pressure measuring device 51 that measures the pressure inside the pipe P.

  If the interval between the stop valves P1 of the pipe P is extremely long, or if the pipe P is not provided with the stop valve P1, a stop cock 40 or the like replacing the stop valve P1 as described later can be used ( (See FIG. 6).

  The low frequency vibration step 200 is a step of vibrating the compressed air inside the pipe P at a low frequency generated by the low frequency generator 20. At this time, as the low frequency vibration process 200, the vibration in the pipe P can be maintained for a long time by applying the low frequency vibration to the compressed air before filling the inside of the pipe P. Further, in the low frequency vibration process 200, after the compressed air is filled in the pipe P, the low frequency vibration process 200 can be vibrated in the pipe P through the pipe P.

  The detection step 300 is a step of detecting a low frequency difference position in the sealed pipe P at a position away from the pipe P (see FIG. 3). The detection means can be arbitrarily selected such as making a determination from a low frequency waveform and converting a low frequency difference into an audible sound.

  When the low frequency difference position in the pipe P is detected in the detection step 300, it is confirmed that this position is a leaking point of the pipe P. For example, in the case where the pipe P is an embedded pipe, the reliability of the detection process 300 can be improved by boring the relevant part and the surroundings and inserting an electronic hearing device 60, a fiber scope, or the like for checking the leaked part of the pipe P. Yes (see FIG. 4). Moreover, in the case of other piping P, a leak location is confirmed according to the condition of the piping P.

  Next, the inspection apparatus of the present invention will be described. The main configuration of the inspection apparatus of the present invention includes a pressure pump 10, a low frequency generator 20, a detector 30, a stop cock 40, and the like.

  The pressure pump 10 sends compressed air into the pipe P, and adjusts the pressure according to the diameter of the pipe P (see FIG. 2). For example, a pipe P having a diameter of 900 to 1000 mm, such as a large-diameter pipe in an agricultural irrigation facility or the like, is filled with compressed air of about 0.08 to 0.09 Mpa. Moreover, since the pipe P used in buildings, factories, houses, etc. is a smaller diameter pipe than the pipe P for agricultural water use facilities, the air pressure of the compressed air is reduced in accordance with the diameter of the pipe.

  The low frequency generator 20 is used to vibrate the compressed air inside the pipe P at a low frequency. The low frequency generator 20 shown in the figure has a compressed air discharge port of the pressure pump 10 connected to a trap, and applies low frequency vibration to the compressed air before filling the inside of the pipe P (see FIG. 5). As described above, it has been clarified through experiments that low-frequency vibration is generated continuously in the pipe P by filling the pipe P with the compressed air to which the low frequency is applied. Moreover, the duration of the low-frequency vibration once given in this way is about 2 hours in the case of a pipe P with a diameter of 1,000 mm and a length of 1 km filled with compressed air of about 0.08 to 0.09 Mpa. Has been. In addition, it is known that when the pipe P under the same conditions is set to 500 m, the low frequency remaining time is about one hour.

  The detector 30 is an instrument that detects a low frequency in the sealed pipe P (see FIG. 3). As this detector 30, for example, a pickup sensor 31 that detects a leak location, a preamplifier 32 that amplifies the detected low frequency, a level meter 33 that visualizes this low frequency, and a headphone 34 that an inspector wears. Consists of. However, this type of detector 30 may be any device as long as it can detect a low frequency in the pipe P and detect a different location, that is, a leak location.

  The stop cock 40 is mainly used for a pipe P of a large-diameter pipe having a diameter of 900 to 1000 mm in an agricultural water use facility or the like. For example, the leakage investigation range of the pipe P is arbitrarily set by installing it detachably in a place where the end of the pipe P cannot be sealed with the water stop valve P1 (see FIG. 6). The stop cock 40 in the illustrated example is provided with a support plate 42 whose upper and lower ends are widened via a jack 41 disposed substantially at the center (see FIG. 7). The support plate 42 is a member that is formed so as to be freely assembled inside the pipe P, and the upper and lower end portions are crimped and fixed inside the pipe P by extending a jack 41 located in the center. The support plate 42 is robustly made of a metal material such as aluminum.

  A holding plate 43 is disposed inside the support plate 42 fixed in the pipe P. The pressing plate 43 is a circular plate whose outer peripheral surface is in close contact with the inner peripheral surface of the pipe P, and is configured to be assembled inside the pipe P. The press plate 43 is preferably made of a metal material such as an aluminum plate, but can be changed to other materials. The holding plate 43 in the illustrated example is divided into an upper part 43A, a middle part 43B, and a lower part 43C (see FIG. 8), and is configured to connect these with a bolt 43D inside the pipe P (see FIG. 9). ).

  On the other hand, a sealing body 44 made of a pressure-resistant rubber tube is disposed inside the holding plate 43 (see FIG. 6). By inflating the sealing body 44 inside the pipe P, when the compressed air is sealed, the sealing body 44 is compressed and deformed and pressed tightly inside the pipe P, thereby providing a sealing effect. is there. Further, since the sealing plate 45 in the illustrated example uses a rubber tube, a sealing plate 45 for sealing the central opening is provided. And by arranging such a stop cock 40 in the pipe P, it becomes possible to freely set an inspection section of the pipe P composed of a large-diameter pipe particularly in an agricultural water use facility.

  According to the present invention, it is possible to detect leaks in all distribution pipes and gas pipes, and leakage detection of pipes in all fields such as agricultural water pipes, office and household pipes, power generation pipes, and blast furnace pipes. Can be used.

P Piping P1 Stop valve 10 Pressure pump 20 Low frequency generator 30 Detector 31 Pickup sensor 32 Preamplifier 33 Level meter 34 Headphone 40 Stop cock 41 Jack 42 Support plate 43 Press plate 43A Upper part 43B Middle part 43C Lower part 43D Bolt 44 Sealing body 50 barometer 51 In-pipe pressure measuring device 100 Compressed air filling process 200 Low frequency vibration process 300 Detection process

Claims (4)

A leak pipe inspection method for detecting leaked parts of pipes, which is a method of filling compressed air with a pressure pump inside a pipe that has been hollowed by sealing the inspection section, and a low frequency generated by a low frequency generator. It consists of a low-frequency vibration process that causes low-frequency vibration inside the pipe at a frequency and a detection process that detects the low frequency in the inspection section with a detector,
In the low frequency vibration process, low frequency vibration is given to the compressed air before filling the inside of the pipe, and the compressed air is filled inside the pipe, thereby generating low frequency vibration inside the pipe and the compressed air is filled. A leak pipe inspection method characterized by detecting a low frequency difference position inside a pipe at a position away from the pipe. A leak pipe inspection device that detects leaking parts of pipes, which is a pressure pump that fills the inside of the pipe with the inspection section sealed and filled with compressed air, and low frequency generation that vibrates the compressed air inside the pipe at a low frequency And a detector that detects low frequencies in the sealed pipe,
The low frequency generator is connected to the compressed air discharge port of the pressure pump, and is configured to give low frequency vibration to the compressed air before filling the inside of the pipe. A leak pipe inspection device characterized in that a low frequency difference position is sensed at a position away from the pipe.   The pipe is a large-diameter water distribution pipe buried in the ground, the inspection section filled with compressed air by the pressure pump is sealed with a stop cock, and the pressure pump is placed inside the inspection section where the pipe is hollowed The compressed air according to claim 2, wherein the low frequency generator vibrates the low frequency in the compressed air inside the pipe, and detects the low frequency difference position on the ground surface portion of the pipe. Leak pipe inspection device.   The stop cock is composed of a support plate whose both end portions are expanded via a jack disposed at a substantially central portion, and a bulging pressure-resistant sealing body disposed inside the support plate. The leak pipe inspection device according to claim 3.

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