JP2012002513A - Conduit inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conduit inspection device capable of automating inspection of a buried piping and suitable for miniaturization.SOLUTION: A conduit inspection device comprises: position detecting means 7 for detecting the position of the device within a conduit; sound pressure detecting means 5 and water pressure detecting means 6 for detecting a sound pressure and a water pressure in the conduit; a branch determining circuit for determining a branch of a water stream based on a signal from the pressure detecting means; and control means 10 for controlling the position detecting means 7, the sound pressure detecting means 5, the water pressure detecting means 6, and the branch determining circuit. The control means 10 puts the sound pressure detecting means 5, the water pressure detecting means 6, and the position detecting means 7 into operation simultaneously while moving in the conduit to obtain information on a water leakage position.

Description

  The present invention relates to a pipe inspection method such as a water pipe and a pipe inspection device.

  Diagnosis of abnormal locations is difficult for pipes embedded in the ground, such as water pipes, or pipes provided with a heat insulating material or structure on the surface. For this reason, there is a problem in that water leaks and stolen water are overlooked in water supply pipelines, and the yield of water charges decreases. In the world's waterworks, there are many water utilities with an effective rate of 80% or less, and in developing countries there are many cases of 60% or less. If there is a lot of water leakage, the function of the water pump will not function sufficiently and water will be cut off, or there will be a hollow in the ground due to water leakage and the road will collapse, which will have a large impact on society as a whole. Currently, the effective rate of water supply in Japan is about 90%, which is the highest level in the world. However, as the legal service life of water distribution pipes is approaching, there is an increasing demand for quickly detecting the occurrence of abnormalities.

  In general, the number of water leaks is large in the number of pipes and terminal pipes (distribution pipes and water supply pipes) having a long extension distance and their junctions. On the other hand, although there are few cases where water leakage occurs in a pipe with a larger diameter such as a water distribution main, there is a feature that the damage amount per case and the range of influence are large. In the latter case, there are cases where an abnormality occurs in the pipe joint such as an earthquake, and there are cases where the wall thickness is ruptured due to a decrease in the wall thickness due to corrosion.

  Currently, the detection of water leakage points in Japan is performed in the following three steps.

  First stage: The occurrence of abnormalities is detected by water pressure sensors installed at many places in the pipeline. Or get a water leak report from a water user.

  Second stage: Narrow down the points of water leakage.

  Third stage: Insert the inspection tool into the narrowing point and check the water leakage point.

  In the second stage, technicians contact an acoustic sensor with the road surface or a part of the distribution pipe facility to find the location of the leak while listening to high-frequency sound caused by water leak, or leak of tracer gas such as helium dissolved in water There is a method of detecting a spot on the ground and finding a point.

  Both are labor-intensive work by skilled technicians, and the water distribution pipes are buried along the road, so it is necessary to work while considering traffic. It takes time and money. In order to quickly cope with water leakage, it is necessary to develop a technology for enhancing the first-stage sensing network and automating the second-stage work.

  In order to automate the work of the second stage, it is ideal to satisfy the following conditions. 1. Minimize modifications to existing piping equipment and installation of new equipment. 2. The ability to automatically investigate and analyze results without the need for skilled operators. 3. Applicable to end pipes with small inner diameter.

As a prior art with such aim, a camera equipped with a power supply, storage device, and communication device is inserted into the water distribution pipe, the inside of the pipe is photographed while being passively moved by the water flow, and the image is analyzed after being collected There is a method of performing (see Patent Document 1). In addition, there is a method of introducing underwater microphones into water pipes from two or more fire hydrants, receiving high-frequency sound due to water leakage with a plurality of microphones, and estimating the water leakage point from the ratio of the sound intensity received at the plurality of locations (Patent Document) 2).

JP 2007-10513 A JP-A-11-014492

  However, the technique of Patent Document 1 based on image information has the following restrictions. First, it is difficult to detect minute cracks that do not appear in the image or are difficult to confirm. Although micro cracks are sometimes covered with rust on the inner surface of the pipe, they tend to develop into great damage such as pipe rupture starting from such a small crack. Therefore, it cannot be said that detection based only on images has sufficient reliability. Second, it requires illumination means for photographing. For this reason, the power supply tends to be large, making it difficult to handle small-diameter pipes, and limiting the distance that can be investigated at once. Third, since an image has a large amount of information, a large-capacity storage unit and a high-performance analysis unit are required. In reality, it seems that human work is required to confirm the analysis results by skilled technicians.

  In addition, the technique of Patent Document 2 that introduces an underwater microphone to a specific point in a pipe has a restriction that it cannot be estimated in principle when there are a plurality of leaks in the vicinity of the microphone installation point. In addition, the accuracy of the water leak point estimation is higher as the interval between the two microphones is smaller, but the arrangement interval of existing equipment such as a fire hydrant becomes a limiting condition, and the accuracy cannot be increased as necessary. As a result, sufficient position detection accuracy is often not obtained.

  An object of the present invention is to solve the above problems and to realize a pipe inspection method and a pipe inspection apparatus that can automate inspection and are suitable for downsizing.

  In order to solve the above-described conventional problems, a pipe inspection device according to the present invention passively detects a self-position detecting means for detecting a self-position in a pipe through which a liquid flows, and water pressure or sound pressure in the pipe. Pressure detecting means for detecting, a branch determining circuit for determining a branch of a water flow based on a signal from the pressure detecting means, and a control means for controlling the self-position detecting means, the pressure detecting means, and the branch determining circuit. The control means is configured to obtain the position information of water leakage by simultaneously operating the pressure detection means and the self-position detection means while moving in the pipe.

  The inspection method and inspection apparatus of the present invention can detect a high frequency generation point and a water pressure change point due to water leakage with high sensitivity by detecting pressure information while moving the pipe inspection device in the pipe. Yes, it is possible to detect abnormalities with high accuracy. Further, since the power consumption is relatively small and the amount of signal to be detected is small, it is suitable for downsizing the entire apparatus including the power supply unit and the storage device.

Overall configuration diagram of a pipeline inspection apparatus according to Embodiment 1 of the present invention The sketch of the inspection apparatus main body of the pipeline inspection apparatus in Embodiment 1 of this invention Explanatory drawing for demonstrating the inspection method in Embodiment 1 of this invention Explanatory drawing for explaining other inspection methods Explanatory drawing for explaining other inspection methods

  The first invention is based on a self-position detecting means for detecting a self-position in a pipeline through which a liquid flows, a pressure detecting means for detecting a pressure propagating in water in the pipe, and a signal from the pressure detecting means. A leakage detection circuit for detecting the occurrence of leakage, and a control means for controlling the self-position detection means, the pressure detection means, and the leakage detection circuit, and the control means extends in the longitudinal direction in the pipeline. It is a pipe line inspection method in which the leak detection circuit is operated by operating the leak detection circuit based on signals collected by simultaneously operating the pressure detection means and the self-position detection means while moving along the line. . By detecting the pressure information while moving the pipe inspection device in the pipe, it is possible to detect the pressure information peculiar to water leakage with high sensitivity and to detect the occurrence point of water leakage with high accuracy. . Further, since the power consumption is relatively small and the amount of signal to be detected is small, it is suitable for downsizing the entire apparatus including the power supply unit and the storage device.

  In particular, in the pipe inspection method according to the first aspect, the pressure detection means is a sound pressure detection means for detecting an acoustic sound pressure of a predetermined frequency, and the control means is a predetermined sound pressure while moving. The occurrence of water leakage is determined by detecting the above.

  According to a third invention, in particular, in the pipe inspection method according to the first invention, the control means has an input means for inputting a charging position into the pipe and a recovery position from the pipe, and the detected water leakage The position information is corrected based on the input position information and the collection position information to the conduit.

  In a fourth aspect of the invention, in particular, in the pipe line inspection method according to any one of the first to third aspects of the invention, the pressure detection means includes a water pressure detection means for detecting a water pressure, and a sound pressure for detecting an acoustic sound pressure of a predetermined frequency. Both of the detection means, the control means, a branch determination circuit that determines the branch of the pipeline based on the water pressure information obtained by the water pressure detection means, and a pipeline that collates with the arrangement information of the pipeline obtained separately And an information collating unit, collating the branch position information of the pipeline determined by the branch determination circuit with the arrangement information of the pipeline, and the branch position of the pipeline so that the degree of coincidence between them is the highest The leak position information is detected after correcting the information.

  According to a fifth aspect of the invention, in particular, in the pipe inspection method according to the fourth aspect of the invention, the pipe information collating unit collates the corrected branch position information of the pipe with the arrangement information of the pipe again, and the inconsistent branch Is determined to be an abnormal branch water flow.

  In a sixth aspect of the invention, in particular, in the pipe inspection method according to the fifth aspect of the invention, the pipe information collating means detects water leakage when a branch of water flow is measured at a position where no branch pipe is described in the pipe information. Alternatively, it is determined that theft has occurred.

  According to a seventh aspect of the invention, in particular, in the pipe inspection method of the fifth aspect, the pipe information verification means is provided when the branch of the water flow is not measured at the position where the branch pipe is described in the pipe information. It is determined that the branch water channel is closed.

  The eighth invention is a pipe inspection device using the pipe inspection method according to any one of the first to seventh inventions, in particular, storage means for storing detection information or determination result information, and information in the storage means Is connected to an external device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is an overall configuration diagram of a pipe line inspection device according to a first embodiment of the present invention.

  In FIG. 1, a pipe inspection apparatus includes an inspection apparatus main body 1, a cable 2 connected to the inspection apparatus main body 1, wireless power feeding means 3 for wirelessly charging the inspection apparatus main body 1, and wireless reception of information with the inspection apparatus main body 1. It is comprised from the radio | wireless transmission / reception means 4 which performs transmission. Further, the inspection apparatus main body 1 detects the angle and acceleration information by detecting the sound pressure detecting means 5 for detecting the frequency and sound pressure of the sound propagating in the water, the water pressure detecting means 6 for detecting the water pressure in the pipeline, and the angle and acceleration information. Information connecting means 9 for receiving and transmitting information between the own position detecting means 7 such as a gyroscope for detecting the own position of the inspection apparatus main body 1, the storage means 8 for storing the detected information, and the wireless transmitting / receiving means 4. And the control means 10 and the secondary battery 11 are accommodated in a waterproof housing. The secondary battery 11 housed in the inspection apparatus main body 1 is charged by the wireless power feeding means 3.

  The inspection apparatus main body 1 is provided with a specific gravity of about 1.0 like water and exhibits neutral buoyancy in water. The size of the inspection apparatus main body 1 in the minor axis direction is about 10 to 20 mm, and is a size that can be put into a general water distribution small pipe having an inner diameter of 75 mm or more.

  First, the inspection procedure for the pipe inspection apparatus configured as described above will be described. As shown in FIG. 3 (a), the inspection apparatus main body 1 is introduced into the water supply pipe 14 from the inlet 13 and is recovered from the pipe 14 at the downstream recovery port 15. A fire hydrant repair valve or the like can be used as the input port 13 and the recovery port 15. Although the water distribution pipe network of the water supply is provided in a mesh shape, the input port 13 and the recovery port 15 can be selected based on the management information of the water pressure and flow velocity in the pipe.

  The line to be introduced is basically assumed to be a straight line, and when the T-shaped branch is downstream, the inspection apparatus main body 1 is collected before the branch. The cable 2 is connected to prevent the location of the inspection apparatus body 1 from becoming unknown in the pipe 14 in case the inspection apparatus body 1 cannot be recovered as scheduled.

  Moreover, when a pipe line has a branch pipe, there exists a possibility that the test | inspection apparatus main body 1 may approach into a branch pipe contrary to prediction before injection | throwing-in. Therefore, as shown in FIG. 2, when the maximum inner diameter φ1 of the known branch pipe is equal to or larger than the outer diameter φ2 of the inspection apparatus main body 1, the intrusion prevention means 12 having an outer diameter φ3 larger than φ1 is provided as the inspection apparatus main body. Install outside of 1. Ingress prevention means 12 having φ3 of various sizes is prepared in accordance with various pipes to be inspected. The intrusion prevention means 12 is covered with silicone rubber or the like so as not to generate acoustic noise even if it touches the inner surface of the conduit 14. Further, by providing a cavity inside the entry preventing means 12, the specific gravity of the entry preventing means 12 alone is made to be about 1.0.

  The inspection apparatus main body 1 thrown into the pipe 14 detects the acoustic signal and the water pressure while passively moving with running water, and stores the detection information in the storage unit 8. After the inspection apparatus main body 1 is collected on the ground, the user takes the detection information into the control means 10 'such as a computer by cooperating the wireless transmission / reception means 4 and the information connection means 9, and detects the water leakage detection circuit on the computer software. And the point of occurrence of abnormality is analyzed by the pipe line information collating means. Hereinafter, the detection method and the analysis method will be described in order for sound pressure and water pressure signals.

  When water leakage occurs in a pipe having a water pressure of 0.1 MPa or more, high-frequency sound in the region of 300 Hz to several tens of kHz is generated at the water leakage point. The same high-frequency sound is also generated by a high-speed water flow that is locally disturbed at a branch point or the like, but can generally be distinguished because the sound pressure is relatively high at a water leakage point.

FIG. 3B shows the sound pressure data detected by the sound pressure detecting means 5 of the inspection apparatus main body 1 as the pipe line 1.
It is an example plotted with the horizontal distance of 4 as the horizontal axis. The horizontal distance is a measured value obtained from the position information obtained by the own position detecting means 7. In this example, the sound exceeding the predetermined threshold T at the point of the distance Lx with the insertion port 13 as the origin of the horizontal axis, and the weak local sound at the points of the distances La, Lb, and Lc were measured. In this case, the water leakage detection circuit determines that water leakage has occurred at the distance Lx. Further, the sudden drop in the sound pressure measured at the point of the distance Ld is due to the inspection apparatus body 1 being recovered from the recovery port 15.

The difference between the actual distance LD between the input port 13 and the recovery port 15 (FIG. 3 (d)) and the measured distance Ld is a result of accumulation of measurement errors by the self-position detecting means 7. The sound pressure information (FIG. 3 (b)) taken into the control means 10 ′ is collated with known pipe line information (FIG. 3 (c)) by the pipe line information collating means, and at the distances La, Lb, Lc. It is determined that the local increase in sound pressure is due to the occurrence of turbulent flow at the branch point of the water flow to the branch pipes A, B, and C. The pipeline information collating means is configured so that the known arrangement distances L _A , L _B , L _C , and L _D of the branch pipes A, B, and C and the recovery port 15 coincide with the measured distances La, Lb, Lc, and Ld. By correcting the horizontal distance information, corrected information (FIG. 3D) is obtained. The user is notified of the corrected leak position Lx.

  FIG. 4 is an example in which water leakage is detected by using the sound pressure detection means 5 and the water pressure detection means 6 in combination. A description will be given centering on differences from the example of FIG. 4 (b) and 4 (c), the horizontal distance (after correction) of the pipe 14 is calculated from the sound pressure data detected by the sound pressure detection means 5 of the inspection apparatus body 1 and the water pressure data detected by the water pressure detection means 6. A graph plotted on the horizontal axis is shown (in this example, the data before correction is omitted).

  As shown in FIG. 4B, an acoustic signal exceeding the sound pressure threshold T specific to water leakage is not detected. On the other hand, a drop in water pressure was detected at a position (distance Lx) that was not assumed from the pipeline information (Fig. 4 (d)) such as a pipeline diagram (Fig. 4 (c)). In such a case, at a distance Lx, it is determined that a relatively large flow rate of water leakage has occurred, for example, the pipe joint has been disconnected, or that water has been stolen.

  When the area of the water leakage location is large to some extent, the water leakage does not become a high-pressure fountain and does not generate a specific high frequency, so that it is difficult to detect the sound system alone despite a serious abnormality. In addition, the acoustic system alone is difficult to detect even when the water pressure is 0.1 MPa or less due to the performance or problems of the pumping equipment in other countries. As described above, both detection means have advantages and disadvantages. Therefore, when a problem occurring in a pipeline can be assumed in advance, it is preferable to use either according to the problem or to investigate using both detection means in combination.

FIG. 5 shows another application example when the water pressure detecting means 6 and the pipe line information collating means are used in combination. The pipe line information matching means corrects the horizontal distance information so that the known arrangement distances L _A , L _C , and L _D of the branch pipes A and C and the recovery port 15 coincide with the measured distances La, Lc, and Ld. Thus, the corrected information (FIG. 5D) is obtained. Furthermore conduit information collating means compares the conduit information (FIG. 5 (c)) and the corrected information (FIG. 5 (d)), the water pressure changes that are contemplated by the presence of a branch pipe B is L _B It finds that it cannot be seen in the position, and determines the closing abnormality Y of the branch pipe B.

  As described above, the pipe inspection method and pipe inspection apparatus according to the present invention can detect an abnormal part with high sensitivity and accuracy while moving the inspection apparatus main body in the pipe, so that the heat insulating material and the soundproofing material It can also be applied to inspection of liquid pipes that are difficult to inspect from the outside.

DESCRIPTION OF SYMBOLS 1 Inspection apparatus main body 2 Cable 3 Wireless power supply means 4 Wireless transmission / reception means 5 Sound pressure detection means 6 Water pressure detection means 7 Self-position detection means 8 Storage means 9 Information connection means 10 Control means 10 'Control means 11 Secondary battery 12 Invasion prevention Means 13 Input port 14 Pipe line 15 Recovery port 16 Confirmation point

Claims (8)

Self-position detecting means for detecting its own position in the pipe through which the liquid flows, pressure detecting means for detecting the pressure propagating in the water in the pipe, and detecting the occurrence of water leakage based on a signal from the pressure detecting means And a control means for controlling the self-position detection means, the pressure detection means, and the water leakage detection circuit, and the control means moves while moving along the longitudinal direction in the pipeline. A pipeline inspection apparatus that operates the water leakage detection circuit based on signals collected by simultaneously operating the pressure detection unit and the self-position detection unit, and obtains the water leakage occurrence position information. The pressure detection means is a sound pressure detection means for detecting an acoustic sound pressure of a predetermined frequency, and the control means determines the occurrence of water leakage by detecting the predetermined sound pressure while moving. Pipe inspection device. The control means has an input means for inputting the input position to the pipe line and the collection position from the pipe line, and corrects the detected water leakage position information based on the input position information and the collection position information to the pipe line. The pipe line inspection method device according to claim 1 or 2, wherein the apparatus is used. The pressure detection means includes both a water pressure detection means for detecting a water pressure and a sound pressure detection means for detecting an acoustic sound pressure of a predetermined frequency, and the control means is a pipe based on the water pressure information obtained by the water pressure detection means. A branch determination circuit for determining a branch of the road, and pipe information collating means for collating with separately obtained pipe arrangement information, the branch position information of the pipe determined by the branch judgment circuit and the pipe In any one of Claims 1-3 which collated with the arrangement information of a road, and detected water leak position information after correcting the branch position information of the said pipe | tube so that both coincidence might become the highest. The pipe line inspection device described. 5. The pipe inspection according to claim 4, wherein the pipe information collating means collates the corrected branch position information with the pipe arrangement information again, and determines that the inconsistent branch is an abnormal branch water flow. apparatus. The pipe line information collating means judges that water leakage or stealing has occurred when a branch of water flow is measured at a position where no branch pipe line is described in the pipe line information. Pipe inspection device. The pipe line information collating means judges that the branch water path is closed when the branch of the water flow is not measured at the position where the branch pipe line is described in the pipe line information. Pipe inspection device. The pipe line inspection device according to any one of claims 1 to 7, further comprising: a storage unit that stores detection information or determination result information; and an information connection unit that outputs information to an external device in the storage unit.