A method for accurately locating leakage points of buried gas pipelines using far-field eddy current technology

Abstract

The present invention discloses a method for accurately locating a leakage point of a buried gas pipeline by adopting a far-field eddy current technology. The method comprises the following steps: inserting a far-field eddy current internal inspection device from a reserved gate valve into the interior of the buried gas pipeline, introducing gas into the buried gas pipeline, and using the gas to push the far-field eddy current internal inspection device to move inside the buried gas pipeline. A gyroscope sensor is used to sense the position of the far-field eddy current internal inspection device in the buried gas pipeline in real time. When the far-field eddy current internal inspection device detects that the wall thickness of the buried gas pipeline is between 0 and 0.4 mm, it is determined that a pipeline leakage has occurred at the current position. When the far-field eddy current internal inspection device detects that the wall thickness of the buried gas pipeline is greater than 0.4 mm, no leakage occurs in the pipeline at the current position. The far-field eddy current internal inspection device continues to move in the buried gas pipeline for detection. This method has high detection efficiency and does not require large-scale damage to the road surface. In addition, the far-field eddy current technology is used to improve the accuracy of pipeline leakage position detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of buried gas pipeline leakage point detection, and specifically relates to a method for accurately locating the leakage point of a buried gas pipeline by adopting far-field eddy current technology. Background Art

[0002] As the service life of urban gas pipelines increases, urban gas pipeline leakage is becoming more and more common. In recent years, there have been cases of explosion accidents caused by leakage of urban gas pipelines. The commonly used method for locating the leakage point of buried gas pipelines is the drilling concentration value method. This method drills multiple holes along the buried pipeline from the ground, measures the concentration of the gas in the hole, and judges the point with the highest concentration value as the leakage point. In order to locate the position of the gas pipeline leakage point, it is necessary to drill more holes on the ground above the pipeline. The more the density and number of holes, the higher the positioning accuracy.

[0003] However, this method has the following defects:

[0004] 1. As urban gas pipelines are often laid underground in residential areas and on roads, excavation affects residents’ lives and road traffic, and large-scale overall excavation is not feasible.

[0005] 2. The gas leaking from the pipeline will diffuse along the pipeline into the surrounding signal gate wells or other buried pipelines. It is common that the leakage point cannot be found after excavation based on the concentration value, and the location of the leakage point cannot be accurately located.

[0006] To this end, we need to propose a method of using far-field eddy current technology to accurately locate the leakage point of buried gas pipelines to solve the above-mentioned problems, so that the leakage point of the pipeline can be accurately located through internal detection. Summary of the invention

[0007] The purpose of the present invention is to provide a method for accurately locating the leakage point of a buried gas pipeline by using far-field eddy current technology. The detection efficiency is fast and does not require large-scale damage to the road surface. The far-field eddy current technology is used to improve the accuracy of pipeline leakage position detection to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for accurately locating the leakage point of a buried gas pipeline using far-field eddy current technology includes the following steps:

[0010] S1. Inserting a remote-field eddy current internal inspection device from a reserved gate valve into the interior of the buried gas pipe, wherein the remote-field eddy current internal inspection device is equipped with an odometer and a gyro sensor;

[0011] S2. Introduce gas into the buried gas pipe, and use the gas to push the remote field eddy current internal inspection device to move inside the buried gas pipe;

[0012] S3, using a gyro sensor to sense the position of the remote field eddy current internal inspection device in the buried gas pipe in real time;

[0013] S4. When the remote-field eddy current internal inspection device detects that the wall thickness of the buried gas pipe is between 0 and 0.4 mm, it is determined that a pipeline leak has occurred at the current location;

[0014] S5. When the far-field eddy current internal inspection device detects that the wall thickness of the buried gas pipe is greater than 0.4 mm, there is no leakage in the pipeline at the current position, and the far-field eddy current internal inspection device continues to move inside the buried gas pipe for inspection.

[0015] Preferably, the far-field eddy current internal inspection device includes a detection probe and an instrument compartment, the detection probe includes a transmitting coil and a receiving coil, a guide assembly is installed at one end of the receiving coil, the other end of the receiving coil is connected to one end of the transmitting coil through a PU tube, the other end of the transmitting coil is connected to one end of the instrument compartment through the PU tube, the other end of the instrument compartment is connected to a mileage wheel through the PU tube, and support centering assemblies are installed on the receiving coil, the transmitting coil and the instrument compartment.

[0016] Preferably, the receiving coil is configured as a detection coil, and the transmitting coil is configured as an excitation coil. The magnetic force emitted by the excitation coil diffuses outward through the wall of the buried gas pipe, and diffuses inward through the wall of the buried gas pipe again in the far field to be received by the detection coil. The signal amplitude and phase received by the detection coil are measured by acquisition software to calculate the thickness of the pipe wall. When the thickness of the wall of the buried gas pipe where the detection coil is located is less than 0.4 mm, it is determined that a leakage occurs in the wall of the buried gas pipe where the detection coil is located.

[0017] Preferably, each group of the supporting centering components includes two centering leather cups, and a plurality of triangular protrusions are fixed at equal angles on the outer wall of the centering leather cups. The two centering leather cups of multiple groups of the supporting centering components are respectively installed at both ends of the receiving coil, both ends of the transmitting coil and both ends of the instrument compartment.

[0018] Preferably, the guide assembly includes a bracket and a guide wheel mounted on the bracket, and the bracket is fixed at a center position of one end of the receiving coil.

[0019] Preferably, the mileage wheel comprises a fixed seat and a plurality of movable rollers, the plurality of movable rollers are mounted at equal angles around the fixed seat, and a mounting cavity for mounting the plurality of movable rollers is provided on a side wall of the fixed seat.

[0020] Preferably, the movable roller includes a first connecting rod, a second connecting rod and a movable wheel installed at one end of the second connecting rod, the other end of the second connecting rod is rotatably connected to one end of the first connecting rod, and the other end of the second connecting rod and the other end of the first connecting rod are respectively rotatably connected to both sides of the mounting cavity.

[0021] Preferably, a battery holder and a gyro sensor are installed in the instrument compartment, a lithium battery is installed in the battery holder, a controller is installed on one side of the battery holder, and the controller is respectively connected to the receiving coil, the transmitting coil and the gyro sensor through wires.

[0022] Preferably, the PU tube is configured as a soft PU tube, and the PU tube between the receiving coil and the transmitting coil, the PU tube between the transmitting coil and the instrument compartment, and the PU tube between the instrument compartment and the mileage wheel are connected in sequence.

[0023] Preferably, when gas is introduced into the buried gas pipe, the air pump is first connected to the gas source through the gate valve to the buried gas pipe, and then the pressure value of the introduced gas is set according to the diameter and length of the buried gas pipe, so that the gas can push the far-field eddy current internal inspection device to move in the buried gas pipeline.

[0024] The method for accurately locating the leakage point of a buried gas pipeline using the far-field eddy current technology proposed in the present invention has the following advantages compared with the prior art:

[0025] 1. The present invention inserts the far-field eddy current internal inspection device from the reserved gate valve into the interior of the buried gas pipe, and then introduces gas into the buried gas pipe. The gas is used to push the far-field eddy current internal inspection device to move inside the buried gas pipe, and a gyroscope sensor is used to sense the position of the far-field eddy current internal inspection device in the buried gas pipe in real time. When the far-field eddy current internal inspection device detects that the pipe wall thickness of the buried gas pipe is between 0-0.4mm, it is determined that a pipeline leakage has occurred at the current position. The detection efficiency is fast, and there is no need to damage the road surface on a large scale. In addition, the far-field eddy current technology is used to improve the accuracy of pipeline leakage position detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the remote field eddy current internal inspection device of the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the guide assembly and the receiving coil of the far-field eddy current internal inspection device of the present invention;

[0029] Figure 4 It is a schematic diagram of the cross-sectional structure of the mileage wheel of the remote field eddy current internal inspection device of the present invention;

[0030] Figure 5 It is a schematic diagram of the working principle of the detection coil and the excitation coil of the present invention;

[0031] Figure 6 This is a waveform comparison diagram of the electromagnetic wave emitted by the excitation coil of the present invention passing through the pipe wall.

[0032] In the figure: 1. guide assembly; 11. bracket; 12. guide wheel; 2. receiving coil; 3. transmitting coil; 4. instrument compartment; 5. mileage wheel; 51. fixed seat; 52. movable roller; 521. first connecting rod; 522. second connecting rod; 523. moving wheel; 53. installation cavity; 6. PU tube; 7. support centering assembly; 71. centering leather cup; 72. protrusion. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] The present invention provides Figure 1-4 The method for accurately locating the leakage point of a buried gas pipeline using the far-field eddy current technology shown in the figure includes the following steps:

[0035] S1. Insert the remote-field eddy current internal inspection device from the reserved gate valve into the interior of the buried gas pipe, wherein the remote-field eddy current internal inspection device is equipped with an odometer 5 and a gyro sensor;

[0036] S2. Introduce gas into the buried gas pipe, and use the gas to push the remote field eddy current internal inspection device to move inside the buried gas pipe;

[0037] When gas is introduced into the buried gas pipe, the air pump is first used to connect the gas source to the buried gas pipe through the gate valve, and then the pressure value of the introduced gas is set according to the diameter and length of the buried gas pipe, so that the gas can push the far-field eddy current internal inspection device to move in the buried gas pipeline.

[0038] S3, using a gyro sensor to sense the position of the remote field eddy current internal inspection device in the buried gas pipe in real time;

[0039] Gyroscope sensors measure angular velocity by detecting the amount of rotation of an object around its axis and using the law of conservation of angular momentum. When an object rotates, the gyroscope sensor senses the inertial force and measures the change in angular velocity. Gyroscope sensors usually output analog or digital signals to represent the angular velocity of the object. Analog signals are continuously changing voltage or current signals; digital signals represent angular velocity in discrete values. Gyroscope sensors usually have three axes, namely x, y, and z. The angular velocity measured in each axis can represent the rotation of the object around the x, y, and z axes respectively. The gyroscope sensor can accurately sense the location of the far-field eddy current internal inspection device.

[0040] S4. When the remote-field eddy current internal inspection device detects that the wall thickness of the buried gas pipe is between 0 and 0.4 mm, it is determined that a pipeline leak has occurred at the current location;

[0041] At present, there are three types of gas pipes in use on the market, namely common gas pipes, medium-thick wall gas pipes and thick-wall gas pipes. The wall thickness of common gas pipes is 0.8-4.0mm, such as DN15, DN20, DN25, etc.; the wall thickness of medium-thick wall gas pipes is 4.5-7.0mm, such as DN32, DN40, DN50, etc.; the thickness of thick-wall gas pipes is 7.5-12mm, such as DN65, DN80, DN100, etc. Therefore, the thinnest gas pipe wall is also 0.8mm. When the gas pipe wall thickness is less than half of the thinnest gas pipe wall thickness, the gas pipe will present a greater risk during use. Therefore, the gas pipeline leakage judgment standard is set to be less than half of the thinnest gas pipe wall thickness to improve the safety of gas transportation by gas pipes.

[0042] S5. When the far-field eddy current internal inspection device detects that the wall thickness of the buried gas pipe is greater than 0.4 mm, there is no leakage in the pipeline at the current position, and the far-field eddy current internal inspection device continues to move inside the buried gas pipe for inspection.

[0043] Among them, the far-field eddy current internal inspection device includes a detection probe and an instrument compartment 4, the detection probe includes a transmitting coil 3 and a receiving coil 2, one end of the receiving coil 2 is equipped with a guide component 1, the other end of the receiving coil 2 is connected to one end of the transmitting coil 3 through a PU tube 6, the other end of the transmitting coil 3 is connected to one end of the instrument compartment 4 through the PU tube 6, the other end of the instrument compartment 4 is connected to a mileage wheel 5 through the PU tube 6, and the receiving coil 2, the transmitting coil 3 and the instrument compartment 4 are all equipped with a support centering component 7.

[0044] The receiving coil 2 is set as a detection coil, and the transmitting coil 3 is set as an excitation coil. The detection probe composed of the detection coil and the excitation coil is convenient for realizing low-frequency eddy current detection of the pipe wall by using the far-field eddy current technology. The magnetic force emitted by the excitation coil spreads outward through the wall of the buried gas pipe, and spreads inward through the wall of the buried gas pipe again in the far-field area to be received by the detection coil. The signal amplitude and phase received by the detection coil are measured by the acquisition software to calculate the thickness of the pipe wall, such as Figure 5 As shown in the figure, the excitation coil is located in the direct coupling area, the detection coil is located in the far field area, and in the transition area between the far field area and the direct coupling area, the excitation coil emits electromagnetic waves that pass through the pipe wall, and then enters the detection coil from the pipe wall. The waveform of the electromagnetic waves passing through the pipe wall (the pipe wall is usually a steel plate) is shown in the figure below. Figure 6 As shown, the left side is the waveform when the thickness enters normally, and the right side is the waveform when the thickness enters thinly. By comparing the waveforms, we know that the amplitude is attenuated and the phase is shifted. The thicker the steel plate, the greater the amplitude attenuation. The amplitude attenuation is used to calculate the pipe wall thickness. When the wall thickness of the buried gas pipe where the detection coil is located is less than 0.4mm, it is determined that there is a leakage in the wall of the buried gas pipe where the detection coil is located.

[0045] Each group of the support centering components 7 includes two centering leather cups 71, and the outer wall of the centering leather cups 71 is fixed with multiple triangular protrusions 72 at equal angles. The two centering leather cups 71 of multiple groups of the support centering components 7 are respectively installed at both ends of the receiving coil 2, both ends of the transmitting coil 3 and both ends of the instrument compartment 4. Through the restriction of the protrusions 72, the receiving coil 2, the transmitting coil 3 and the instrument compartment 4 are located in the middle position of the buried gas pipe.

[0046] The guide assembly 1 includes a bracket 11 and a guide wheel 12 installed on the bracket 11. The bracket 11 is fixed at the center position of one end of the receiving coil 2. The guide wheel 12 is used to drive the far-field eddy current internal inspection device to move in a directional manner in the buried gas pipe.

[0047] The mileage wheel 5 includes a fixed seat 51 and a plurality of movable rollers 52. The plurality of movable rollers 52 are installed at equal angles around the fixed seat 51, and a mounting cavity 53 for installing the plurality of movable rollers 52 is provided on the side wall of the fixed seat 51. The moving wheel 523 is used to reduce the friction between the far-field eddy current internal inspection device and the inner wall of the buried gas pipe, so as to facilitate the use of a gas source to push the far-field eddy current internal inspection device to move in the buried gas pipe.

[0048] The movable roller 52 includes a first connecting rod 521, a second connecting rod 522 and a moving wheel 523 installed at one end of the second connecting rod 522. The other end of the second connecting rod 522 is rotatably connected to one end of the first connecting rod 521, and the other end of the second connecting rod 522 and the other end of the first connecting rod 521 are respectively rotatably connected to two sides of the installation cavity 53. The first connecting rod 521 and the second connecting rod 522 form a crank connecting rod, so that the movable roller 52 has a certain moving space in the installation cavity 53, which is convenient for use with buried gas pipes of different diameters.

[0049] A battery holder and a gyroscope sensor are installed in the instrument compartment 4, a lithium battery is installed in the battery holder, a controller is installed on one side of the battery holder, the controller is respectively connected to the receiving coil 2, the transmitting coil 3 and the gyroscope sensor through wires, the lithium battery provides power to the receiving coil 2, the transmitting coil 3 and the gyroscope sensor, and the controller controls the operation of the receiving coil 2, the transmitting coil 3 and the gyroscope sensor.

[0050] The PU tube 6 is configured as a soft PU tube, and the PU tube 6 between the receiving coil 2 and the transmitting coil 3, the PU tube 6 between the transmitting coil 3 and the instrument compartment 4, and the PU tube 6 between the instrument compartment 4 and the mileage wheel 5 are connected in sequence. The soft PU tube 6 is used to make the far-field eddy current internal inspection device have a bending effect, which is convenient for passing through the gas bend position.

[0051] In summary, the far-field eddy current internal inspection device is inserted into the interior of the buried gas pipe from the reserved gate valve, and gas is introduced into the buried gas pipe. The gas is used to push the far-field eddy current internal inspection device to move inside the buried gas pipe. The gyroscope sensor is used to sense the position of the far-field eddy current internal inspection device in the buried gas pipe in real time. When the far-field eddy current internal inspection device detects that the pipe wall thickness of the buried gas pipe is between 0-0.4mm, it is judged that a pipeline leakage has occurred at the current position. The detection efficiency is fast, and there is no need to damage the road surface on a large scale. The far-field eddy current technology is used to improve the accuracy of pipeline leakage position detection.

[0052] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for accurately locating the leakage point of a buried gas pipeline using far-field eddy current technology, characterized in that: The steps include: S1. Inserting a remote-field eddy current internal inspection device from a reserved gate valve into the interior of a buried gas pipe, wherein the remote-field eddy current internal inspection device is equipped with a mileage wheel (5) and a gyroscope sensor; S2. Gas is introduced into the buried gas pipe, and the gas is used to drive the remote field eddy current internal inspection device to move inside the buried gas pipe; S3, using a gyro sensor to sense the position of the remote field eddy current internal inspection device in the buried gas pipe in real time; S4. When the remote-field eddy current internal inspection device detects that the wall thickness of the buried gas pipe is between 0 and 0.4 mm, it is determined that a pipeline leak has occurred at the current location; S5. When the remote-field eddy current internal inspection device detects that the wall thickness of the buried gas pipe is greater than 0.4 mm, there is no leakage in the pipeline at the current position, and the remote-field eddy current internal inspection device continues to move inside the buried gas pipe for inspection; The remote-field eddy current internal inspection device comprises a detection probe and an instrument compartment (4); the detection probe comprises a transmitting coil (3) and a receiving coil (2); one end of the receiving coil (2) is equipped with a guide assembly (1); the other end of the receiving coil (2) is connected to one end of the transmitting coil (3) via a PU tube (6); the other end of the transmitting coil (3) is connected to one end of the instrument compartment (4) via the PU tube (6); the other end of the instrument compartment (4) is connected to a mileage wheel (5) via the PU tube (6); and the receiving coil (2), the transmitting coil (3) and the instrument compartment (4) are all equipped with a support centering assembly (7); Each group of the support centering components (7) comprises two centering leather cups (71), and the outer wall of the centering leather cups (71) is fixed with a plurality of triangular protrusions (72) at equal angles. The two centering leather cups (71) of the plurality of groups of the support centering components (7) are respectively installed at two ends of the receiving coil (2), two ends of the transmitting coil (3), and two ends of the instrument compartment (4); The guide assembly (1) comprises a bracket (11) and a guide wheel (12) mounted on the bracket (11); the bracket (11) is fixed at a central position of one end of the receiving coil (2); The mileage wheel (5) comprises a fixed seat (51) and a plurality of movable rollers (52), wherein the plurality of movable rollers (52) are mounted at equal angles around the fixed seat (51), and a mounting cavity (53) for mounting the plurality of movable rollers (52) is provided on a side wall of the fixed seat (51); The movable roller (52) comprises a first connecting rod (521), a second connecting rod (522) and a moving wheel (523) mounted on one end of the second connecting rod (522); the other end of the second connecting rod (522) is rotatably connected to one end of the first connecting rod (521); and the other end of the second connecting rod (522) and the other end of the first connecting rod (521) are rotatably connected to two sides of the mounting cavity (53), respectively.

2. The method for accurately locating the leakage point of a buried gas pipeline using far-field eddy current technology according to claim 1 is characterized in that: The receiving coil (2) is configured as a detection coil, and the transmitting coil (3) is configured as an excitation coil. The magnetic force emitted by the excitation coil diffuses outward through the wall of the buried gas pipe, and diffuses inward through the wall of the buried gas pipe again in the far field to be received by the detection coil. The signal amplitude and phase received by the detection coil are measured by acquisition software to calculate the thickness of the pipe wall. When the thickness of the wall of the buried gas pipe where the detection coil is located is less than 0.4 mm, it is determined that the wall of the buried gas pipe where the detection coil is located has a leakage phenomenon.

3. The method for accurately locating the leakage point of a buried gas pipeline using far-field eddy current technology according to claim 1 is characterized in that: A battery holder and the gyro sensor are installed in the instrument compartment (4), a lithium battery is installed in the battery holder, a controller is installed on one side of the battery holder, and the controller is respectively connected to the receiving coil (2), the transmitting coil (3) and the gyro sensor via wires.

4. The method for accurately locating the leakage point of a buried gas pipeline using far-field eddy current technology according to claim 3 is characterized in that: The PU tube (6) is configured as a soft PU tube, and the PU tube (6) between the receiving coil (2) and the transmitting coil (3), the PU tube (6) between the transmitting coil (3) and the instrument compartment (4), and the PU tube (6) between the instrument compartment (4) and the mileage wheel (5) are sequentially connected.

5. The method for accurately locating the leakage point of a buried gas pipeline using far-field eddy current technology according to claim 4 is characterized in that: When gas is introduced into the buried gas pipe, the air pump is first used to connect the gas source to the buried gas pipe through the gate valve, and then the pressure value of the introduced gas is set according to the diameter and length of the buried gas pipe, so that the gas can push the far-field eddy current internal inspection device to move in the buried gas pipeline.

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