JP2006313098A - Pipe diagnostic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manage a buried pipe sufficiently by surely and directly grasping the occurrence of a defect such as corrosion or a damage of the buried pipe and its generation position, and to perform measurement simply without requiring a load. <P>SOLUTION: A pipe diagnostic device 100, which is a device for diagnosing existence of a defect caused by corrosion, a damage or the like of the pipe (buried pipe) 20, is characterized by being equipped with two cables 1, 2 arranged on two spots of the buried pipe 20 and having electrode terminals 1a, 2a on the tip, respectively, an impedance measuring means 31 for measuring the impedance between the electrode terminals 1a, 2a by applying an alternating voltage between the electrode terminals 1a, 2a of the two cables 1, 2, and a defect existence estimation means 32 for estimating existence of a defect caused by corrosion, a damage or the like of the buried pipe 20 from measurement results by the impedance measuring means 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pipe diagnostic apparatus that diagnoses the presence or absence of defects due to corrosion, damage, or the like of piping in soil, water, or sea, identifies the position of the defects, and estimates the state of oxidation, corrosion, or damage.

  The gas pipe may be embedded in the soil between the LP gas cylinder and the gas equipment in the house, for example. For this reason, even if corrosion or damage occurs in the soil, it cannot be observed from the outside, causing gas leakage and the like.

The state of corrosion and damage of the buried pipe can be directly observed by excavating the soil up to the buried pipe. However, since this requires cost and labor, a method for observing without digging is, for example, the following patent document 1 is proposed.
Japanese Patent Laid-Open No. 5-128973

  In Patent Document 1, a test piece is embedded in the vicinity of a gas pipe embedded in soil, and an average corrosion rate at the time of measurement is obtained by instantaneous analysis from the measurement result of the AC impedance of the test piece. The tube is managed.

  However, in the above prior art, it is possible to manage corrosion without digging, but since the object to be measured is not a buried gas pipe but a test piece, even if the buried gas pipe is corroded, the corrosion However, there is a problem that it is not always possible to observe with a test piece, and corrosion of the buried gas pipe cannot be grasped directly and surely.

  In addition, because it is a test piece measurement, even if corrosion occurs in the buried gas pipe, the position cannot be specified, and there is a problem that the buried gas pipe cannot be managed sufficiently. .

  Furthermore, when embedding the gas pipe, it is necessary to embed a test piece at the same time, and the cable for connecting the test piece and the measurement circuit must be extended to the ground surface in advance. It was labor intensive in this respect.

  And what can be said for the above gas pipes (buried gas pipes) is the same for various pipes that cannot be directly viewed from the outside in water or underwater, and their maintenance is also difficult.

  The present invention has been proposed in view of the above, and the occurrence of defects such as corrosion and damage of pipes that cannot be directly seen from the outside, and the occurrence position thereof are surely directly grasped, and the pipes are sufficiently managed. It is an object of the present invention to provide a piping diagnostic apparatus that can perform measurement easily without requiring labor.

  In order to achieve the above object, the invention described in claim 1 is arranged at two locations on the piping in a piping diagnostic apparatus for diagnosing the presence or absence of defects due to corrosion, damage, etc. of piping in the soil, water or sea. From the two cables each having an electrode terminal at the tip, an impedance measuring means for measuring an impedance between the electrode terminals by applying an AC voltage between the electrode terminals of the two cables, and a measurement result of the impedance measuring means And a defect presence / absence estimation means for estimating the presence / absence of a defect due to corrosion, damage, or the like of the pipe.

  Further, in the invention described in claim 2, in addition to the configuration of the invention described in claim 1 described above, both of the two cables are arranged in the vicinity of the pipe, or both are in contact with the pipe. One of them is arranged, or one is in contact with the pipe and the other is arranged in the vicinity of the pipe.

  In the invention described in claim 3, in addition to the configuration of the invention described in claim 1 or 2, the impedance measuring means obtains the impedance frequency characteristic of the pipe and corrodes the pipe based on the impedance frequency characteristic. It is characterized by estimating the presence or absence of defects due to damage or the like.

  In the invention according to claim 4, in addition to the configuration of the invention according to any of claims 3 to 3, when it is estimated that the piping is defective by the impedance measuring means, the electrodes of the two cables One of the terminals is fixed, the impedance is measured while moving the other along the pipe, and it is estimated that there is a pipe defect at the other electrode terminal position when the impedance is minimized. It is said.

  The invention according to claim 5 is characterized in that, in addition to the configuration of the invention according to any one of claims 1 to 4, the pipe is a plastic-coated steel gas pipe or an anticorrosion tape white gas pipe. It is said.

  The invention according to claim 6 is a pipe diagnostic apparatus for diagnosing the state of oxidation, corrosion, and damage of pipes in the soil, water, and sea. Impedance measurement means for applying an AC voltage between the electrode terminals of the two cables and measuring the impedance between the electrode terminals, and the state of oxidation, corrosion and damage of the pipe from the measurement result of the impedance measurement means And a state estimating means for estimating.

  In the seventh aspect of the invention, in addition to the configuration of the sixth aspect of the invention described above, the state estimating means obtains an impedance complex diagram from the impedance obtained by measurement, and the impedance complex diagram is obtained. It is characterized by estimating the state of oxidation, corrosion and damage of piping based on the above.

  The invention described in claim 8 is characterized in that, in addition to the configuration of the invention described in claim 6 or 7, the pipe is a white gas pipe or a galvanized white gas pipe. Yes.

  In the piping diagnostic device of the present invention, an AC voltage is applied between the electrode terminals of the cables arranged at two locations of the piping, the impedance between the electrode terminals is measured, and the presence or absence of defects due to corrosion, damage, etc. of the piping is determined from the measurement results. Since the estimation was made, it was possible to directly and reliably grasp the occurrence of corrosion and damage to the pipes, manage the pipes sufficiently, and perform the measurement easily and without labor. Can do.

  When it is estimated that there is a defect in the piping, when one of the electrode terminals of the two cables is fixed and the impedance is measured while moving the other along the piping, the impedance is minimized Because it was estimated that there was a pipe defect at the other electrode terminal position, the defect position of the pipe could be identified, the defect position could be easily identified, and the repair work, etc. was also accurate. Can be done.

  In the piping diagnostic device of the present invention, an AC voltage is applied between the electrode terminals of the cables arranged at two locations of the pipe, the impedance between the electrode terminals is measured, and the corrosion or damage state of the pipe is estimated from the measurement result. As a result, the occurrence of corrosion and damage to the pipes can be ascertained directly, management of the pipes can be performed sufficiently, and measurement can be easily performed without requiring labor. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram of measurement by the piping diagnostic device of the present invention. The piping diagnostic device 100 according to the present invention is a device for diagnosing the presence or absence of a defective portion 21 due to corrosion, damage, or the like of piping 20 in the soil, underwater or underwater, and has two cables 1 and 2 and a device body 3. is doing. Here, it is assumed that the pipe 20 is a gas supply pipe (buried pipe) buried in the soil.

  The buried pipe 20 is a plastic-coated steel gas pipe or an anticorrosion tape-rolled white gas pipe, and is provided, for example, in the soil between the high-pressure gas container 91 and the gas meter 92. Exposed and piped.

  The two cables 1 and 2 are electrically connected at one end side to the apparatus main body 3, and the electrode terminals 1 a and 2 a at the other end side are arranged at two locations on the buried pipe 20. The electrode terminal 1a of the cable 1 is fixed in contact with the ground exposed portion 22 of the buried pipe 20 on the gas meter 92 side, and the electrode terminal 2a of the cable 2 is disposed in the vicinity of the buried pipe 20 in the soil.

  The apparatus main body 3 includes an impedance measuring unit 31 that measures an impedance between the electrode terminals 1a and 2a by applying an AC voltage between the electrode terminals 1a and 2a of the two cables 1 and 2, and a measurement result of the impedance measuring unit 31. And a defect presence / absence estimation means 32 for estimating the presence / absence of the defect portion 21 due to corrosion, damage or the like of the buried pipe 20.

  The impedance measuring means 31 and the defect presence / absence estimating means 32 are constructed around a microcomputer, for example, and include a function for operating the CPU in accordance with the software according to the present invention stored in a memory.

  FIG. 2 is a diagram showing the result of impedance measurement by the piping diagnostic device. The impedance measuring means 31 of the pipe diagnostic device 3 measures the impedance between the electrode terminals 1a and 2a based on the alternating voltage applied between the electrode terminals 1a and 2a of the two cables 1 and 2 as described above. Then, the impedance frequency characteristic when the frequency of the AC voltage is changed as shown in FIG. 2 is obtained. In FIG. 2, the horizontal axis represents frequency and the vertical axis represents impedance absolute value.

  In this impedance frequency characteristic, when the buried pipe 20 is normal without a defect, a locus close to a straight line with a slope of substantially “−1” is drawn as shown by a measurement line A in FIG. On the other hand, if the buried pipe 20 has a defect due to corrosion, damage, or the like, as shown by measurement lines B and C in FIG. 2, a locus close to flat is drawn in a low frequency region. Such a trajectory is drawn for the following general reason.

FIG. 3 is a diagram showing an equivalent circuit of the buried pipe, and FIG. 4 is a diagram for explaining the concept of impedance frequency characteristic measurement. Here, if the buried pipe 20 is a plastic-coated steel gas pipe and has a defect, the equivalent circuit of the buried pipe 20 has a floating capacity (electric capacity between the pipe diagnostic device 3 and the buried pipe 20). , The serial body M and the parallel body of the serial body N. Here, the serial body M is configured by connecting in series the electric resistance C _H of the plastic coating when there is no defect and the soil resistance R _S1 at the shortest distance from the electrode terminal 2 a to the buried pipe 20. In addition, the serial body N has a parallel body N1 in which the polarization resistance R _P at the defective portion 21 and the electric capacity C _P of the defective portion 21 when there is a defect, and the buried tube 20 from the electrode terminal 2a. The soil resistance R _S2 at the shortest distance to the defective portion 21 is connected in series.

In the measurement of impedance frequency characteristics, in the region where the frequency is high, the impedance [{1 / (ωC _H )} + R _S1 ] composed of the electric capacity C _H and the soil resistance R _S1 of the equivalent circuit is measured, and the frequency is low. In the region where (R _S2 )> [{1 / (ωC _H )} + R _S1 ] is established, the impedance due to the series body N caused by the defect portion 21 is measured, and as a result, the impedance frequency characteristic is measured in FIG. As shown by lines B and C, a locus close to flat is drawn in a low frequency region.

If the impedance absolute value is 10 ⁶ Ω or more in the low frequency region, for example, between 1 and 100 Hz, the above defect presence / absence estimation means 32 is defective in the buried pipe 20. If the absolute value of impedance is 10 ⁶ Ω or less, it is determined that there is a defect in the buried pipe 20.

  When it is determined that the buried pipe 20 has a defective portion 21 due to corrosion, damage, or the like, the position of the defective portion 21 is specified as follows.

FIG. 5 is an explanatory diagram when the position of a defective portion of the buried pipe is specified. The horizontal axis in the figure indicates the position of the buried pipe in the length direction, and the vertical axis indicates the impedance absolute value. When it is determined that the defective portion 21 exists in the buried pipe 20, the electrode terminal 2a is moved at a predetermined interval (for example, 1 m interval or 2 m interval) along the length direction (pipe) of the buried tube 20 in FIG. And measure the impedance at each position. The frequency in this case is set to a low value, for example, a constant value between 1 and 100 Hz. When the defect portion 21 exists, when measured at a low frequency, the impedance is dominated by the soil resistance R _S2 between the electrode terminal 2 a and the defect portion 21, and the electrode terminal 2 a is located immediately above the position where the defect portion 21 exists. As the soil moves, its soil resistance R _S2 is minimized. Therefore, when the impedance is measured while moving the electrode terminal 2a along the pipe line of the buried pipe 20, the defect portion 21 exists at a position where the absolute value of the impedance is minimum (point P in FIG. 5). Will be.

  As described above, in the piping diagnostic device 100 according to the present invention, an AC voltage is applied between the electrode terminals 1a and 2a of the cables 1 and 2 arranged at two locations of the buried pipe 20 to reduce the impedance between the electrode terminals 1a and 2a. Since measurement was performed and the presence or absence of defects due to corrosion, damage, or the like of the buried pipe 20 was estimated from the measurement results, the occurrence of corrosion or damage of the buried pipe 20 can be ascertained directly and directly. The tube 20 can be sufficiently managed, and the measurement can be easily performed without requiring labor.

  When it is estimated that the buried pipe 20 is defective, the position of one of the electrode terminals 1a and 2a of the two cables 1 and 2 is fixed, and the other electrode terminal 2a is fixed to the buried pipe. 20, the impedance is measured while moving along the line 20, and it is estimated that there is a defect in the buried pipe 20 at the position of the other electrode terminal 2 a when the impedance absolute value is minimized. The defect position can be easily identified, and the repair work can be accurately performed.

  Next, a second embodiment of the piping diagnostic device of the present invention will be described with reference to FIGS.

  FIG. 6 is an explanatory view of the measurement according to the second embodiment of the piping diagnostic apparatus of the present invention. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The piping diagnostic device 100A in this second embodiment is a device for diagnosing the state of oxidation, corrosion, and damage of the buried pipe 20 made of a white gas pipe or a galvanized white gas pipe. This is different from the first embodiment. The apparatus body 3A includes an impedance measuring means 31A for measuring an impedance between the electrode terminals 1a and 2a by applying an AC voltage between the electrode terminals 1a and 2a of the two cables 1 and 2, and a measurement result of the impedance measuring means 31A. And a state estimating means 32A for estimating the state of oxidation, corrosion, and damage of the buried pipe 20.

  The state estimation means 32A obtains an impedance complex diagram from the impedance obtained by measurement, and estimates the state of oxidation, corrosion, and damage of the buried pipe based on the impedance complex diagram.

  The impedance measuring unit 31A and the state estimating unit 32A are constructed including, for example, a microcomputer, and include a function for operating the CPU in accordance with software according to the present invention stored in a memory.

  FIG. 7 is a diagram illustrating an impedance measurement result obtained by the piping diagnosis apparatus according to the second embodiment. The impedance measuring means 31A of the piping diagnostic device 3A measures the impedance between the electrode terminals 1a and 2a based on the alternating voltage applied between the electrode terminals 1a and 2a of the two cables 1 and 2 as described above. Then, as shown in FIG. 7, an impedance complex diagram when changing the value of the AC voltage is obtained. The horizontal axis in FIG. 7 is the real part of impedance, and the vertical axis is the imaginary part of impedance.

  In this impedance complex diagram, when the buried pipe 20 is normal without defects such as oxidation, corrosion, damage, etc., as shown by the measurement line X in FIG. Become. On the other hand, if oxidation has occurred in the buried pipe 20, as shown by the measurement line Y in FIG. Also, if corrosion has occurred in the buried pipe 20, as shown by the measurement line Z in FIG. 7, a trace that once rises and then drops with a steep slope is drawn, and both the real impedance part and the impedance imaginary part are both small. The result will remain in value. As described above, the impedance complex diagram of the buried pipe 20 draws a characteristic trajectory according to the state of the buried pipe such as oxidation.

  As described above, in the piping diagnostic apparatus 100A according to the second embodiment of the present invention, an AC voltage is applied between the electrode terminals 1a and 2a of the cables 1 and 2 disposed at two locations of the buried pipe 20 to thereby form the electrode terminal 1a. , 2a is measured, and the state of oxidation, corrosion, and damage of the buried pipe 20 is estimated from the measurement result, so that the occurrence of oxidation, corrosion, and damage of the buried pipe 20 can be grasped directly and directly. Therefore, the buried pipe can be sufficiently managed, and the measurement can be easily performed without requiring labor.

  In the above description, the pipe is a gas pipe embedded in the soil, but the present invention can be applied not only to the gas pipe but also to various pipes in water and underwater. . In the case of underwater or seawater, the same result was obtained by substituting the resistance of soil with the resistance of water or seawater.

  Further, the present invention can be similarly applied not only to gas pipes but also to pipes extending from a kerosene tank, a gasoline tank, a water tank, and the like and embedded therein.

It is explanatory drawing of the measurement by the piping diagnostic apparatus of this invention. It is a figure which shows the impedance measurement result by a piping diagnostic apparatus. It is a figure which shows the equivalent circuit of a buried pipe. It is a figure for demonstrating the concept of an impedance frequency characteristic measurement. FIG. 5 is an explanatory diagram when the position of a defective portion of the buried pipe is specified. It is explanatory drawing of the measurement by 2nd Embodiment of the piping diagnostic apparatus of this invention. It is a figure which shows the impedance measurement result by the piping diagnostic apparatus of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cable 1a Electrode terminal 2 Cable 2a Electrode terminal 3 Apparatus main body 3A Apparatus main body 20 Buried pipe 21 Defect part 22 Exposed surface part 31 Impedance measurement means 31A Impedance measurement means 32 Defect existence estimation means 32A State estimation means 91 High pressure gas container 92 Gas meter 100 Piping diagnostic device 100A Piping diagnostic device

Claims (8)

In piping diagnostic equipment that diagnoses the presence or absence of defects due to corrosion, damage, etc. of piping in the soil, water, and sea,
Two cables arranged at two locations of the pipe, each having an electrode terminal at the tip;
Impedance measuring means for applying an alternating voltage between the electrode terminals of the two cables and measuring the impedance between the electrode terminals;
Defect presence / absence estimation means for estimating the presence / absence of defects due to corrosion, damage, etc. of piping from the measurement result of the impedance measurement means,
A piping diagnostic device comprising:   The two cables are either arranged in the vicinity of the pipe, both are arranged in contact with the pipe, or one is in contact with the pipe and the other is arranged in the vicinity of the pipe. Item 2. The piping diagnostic device according to Item 1.   The pipe diagnostic apparatus according to claim 1 or 2, wherein the impedance measuring means obtains impedance frequency characteristics of the pipe and estimates the presence or absence of a defect due to corrosion, damage or the like of the pipe based on the impedance frequency characteristic.   When it is estimated that the piping has a defect by the impedance measuring means, the impedance is minimized by fixing one position of the electrode terminals of the two cables and moving the other along the pipe. The piping diagnostic device according to any one of claims 1 to 3, wherein the other electrode terminal position is estimated to have a piping defect.   The piping diagnosis device according to any one of claims 1 to 4, wherein the piping is a plastic-coated steel gas tube or a corrosion-resistant tape-wound gas tube. In piping diagnostic equipment that diagnoses the state of oxidation, corrosion, and damage of piping in soil, water, and sea,
Two cables arranged at two locations of the pipe, each having an electrode terminal at the tip;
Impedance measuring means for applying an alternating voltage between the electrode terminals of the two cables and measuring the impedance between the electrode terminals;
State estimation means for estimating the state of oxidation, corrosion and damage of the pipe from the measurement result of the impedance measurement means;
A piping diagnostic device comprising:   The pipe diagnosis according to claim 6, wherein the state estimation means obtains an impedance complex diagram from the impedance obtained by measurement, and estimates the state of oxidation, corrosion, and damage of the pipe based on the impedance complex diagram. apparatus.   The pipe diagnosis apparatus according to claim 6 or 7, wherein the pipe is a white gas pipe or a galvanized white gas pipe.

Images