Device for measuring defects in pipeline based on pulsed eddy current

Abstract

The invention relates to the technical field of pipeline defect detection, in particular to a device for measuring defects in a pipeline based on pulsed eddy current, which comprises a measurer and a displacement device for driving the measurer to move, the measurer comprises a detection coil wound with a plurality of turns of detection wires and an excitation coil wound with a plurality of turns of excitation wires, the detection coil and the excitation coil are coaxially arranged, the excitation coil is arranged on the detection coil, and the excitation wires are electrically connected with an alternating current source. According to the defect measuring device, in practical application, the designed measuring device based on the eddy current is used for measuring defects in a pipeline, the detection precision of small-area defects can be greatly improved, and specifically, when the height difference between the measuring device and the defects of the pipe wall is within 100 mm, accurate detection of the defects with the length, width and depth being 10 mm * 10 mm * 5 mm can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline defect detection, and in particular to a pipeline defect measurement device based on pulse eddy current. Background Art

[0002] As the main mode of transportation for energy such as oil and natural gas, the safe operation of pipeline transportation is related to the lifeline of the national economy. In this context, it is very important to detect and repair pipeline defects to effectively avoid pipeline accidents.

[0003] At present, due to the late start of research on internal defect positioning of pipelines in China, the relevant pipeline defect measurement equipment usually has the problems of insufficient defect detection accuracy and low detection sensitivity, which makes it difficult to meet the actual detection needs, especially the detection needs of local small area defects.

[0004] Therefore, there is an urgent need for a pipeline defect measurement device based on pulsed eddy current to effectively improve the detection accuracy of pipeline defects, thereby realizing the detection of local small area defects. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that pipeline defect measurement equipment in the prior art usually has insufficient defect detection accuracy and low detection sensitivity, which is difficult to meet actual detection needs, especially difficult to meet the detection needs of local small area defects, and to provide a pipeline defect measurement device based on pulsed eddy current.

[0006] In order to achieve the above-mentioned object, the present invention provides a device for measuring defects in pipelines based on pulsed eddy currents, the device for measuring defects in pipelines based on pulsed eddy currents comprising a measuring device and a displacement device for driving the measuring device to move; The measuring device comprises a detection coil wound with a plurality of turns of detection wire and an excitation coil wound with a plurality of turns of excitation wire. The detection coil and the excitation coil are coaxially arranged and the excitation coil is arranged on the detection coil. The excitation wire is electrically connected to an alternating current source.

[0007] Preferably, the number of turns of the detection wire wound on the detection coil is 40-60 turns, and the number of turns of the excitation wire wound on the excitation coil is 15-35 turns.

[0008] Preferably, the ratio of the number of turns of the detection wire wound on the detection coil to the number of turns of the excitation wire wound on the excitation coil is 2:1.

[0009] Preferably, the diameter of the detection coil is 10-30 mm, and the diameter of the excitation coil is 20-40 mm.

[0010] Preferably, the ratio of the diameter of the detection coil to the diameter of the excitation coil is 2:3.

[0011] Preferably, the height of the excitation coil is 4-12 mm.

[0012] Preferably, the frequency of the pulse current input into the excitation wire by the alternating current source is 6-15 Hz.

[0013] Preferably, the pulse current is 0.5-1.5A.

[0014] Preferably, the displacement device comprises a fixing seat and a telescopic motor disposed on the fixing seat, and the telescopic motor drives the measuring device to move via a telescopic rod.

[0015] According to the above technical solution, based on the pulse eddy current-based pipeline defect measuring device, by setting an eddy current-based measuring device for measuring defects in the pipeline, in actual application, the detection accuracy of small area defects can be greatly improved. Specifically, when the height difference between the measuring device and the pipe wall defect is within 100mm, accurate detection of defects with a length, width and depth of 10mm*10mm*5mm can be achieved.

[0016] At the same time, by setting the number of turns of the detection wire wound on the detection coil to 40-60 turns, the number of turns of the excitation wire wound on the excitation coil to 15-35 turns, the ratio of the number of turns of the detection wire wound on the detection coil to the number of turns of the excitation wire wound on the excitation coil is 2:1, the diameter of the detection coil is 10-30 mm, the diameter of the excitation coil is 20-40 mm, the ratio of the diameter of the detection coil to the diameter of the excitation coil is 2:3, and the height of the excitation coil is 4-12 mm. In practical applications, the detection accuracy of defects in the pipeline can be further effectively improved, thereby better realizing the detection of local small area defects.

[0017] The frequency of the pulse current input into the excitation wire through the alternating current source is 6-15 Hz and the magnitude of the pulse current is 0.5-1.5 A. In practical applications, the detection accuracy of defects in the pipeline can be further effectively improved, thereby better realizing the detection of local small area defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of a device for measuring defects in pipelines based on pulsed eddy current; Figure 2 It is a schematic diagram of the structure when the detection coil is wound with the detection wire; Figure 3 It is a schematic diagram of the structure when the excitation coil is wound with an excitation wire.

[0019] Description of Reference Numerals 1. Detection coil; 2. Excitation coil; 3. Detection wire; 4. Excitation wire; 5. Displacement device; 6. Pipeline; 7. Defect; 8. Internal detector. DETAILED DESCRIPTION

[0020] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0021] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, unless otherwise specified, features defined as "first" and "second" may explicitly or implicitly include one or more of the features; "plurality" means two or more. The term "include" and any variation thereof means non-exclusive inclusion, possible presence or addition of one or more other features, units, components and / or combinations thereof.

[0022] In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internally connected between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] The present invention provides a device for measuring defects in pipelines based on pulsed eddy currents, such as Figure 1-3 As shown, the pulsed eddy current based pipeline defect measuring device comprises a measuring device and a displacement device 5 for driving the measuring device to move; The measuring device includes a detection coil 1 wound with a plurality of turns of detection wire 3 and an excitation coil 2 wound with a plurality of turns of excitation wire 4. The detection coil 1 and the excitation coil 2 are coaxially arranged and the excitation coil 2 is arranged on the detection coil 1. The excitation wire 4 is electrically connected to an alternating current source.

[0024] In a preferred embodiment, the detection wire 3 and the excitation wire 4 have the same size.

[0025] According to the above technical solution, based on the pulse eddy current-based pipeline defect measuring device, by setting an eddy current-based measuring device for measuring defects in the pipeline, in actual application, the detection accuracy of small area defects can be greatly improved. Specifically, when the height difference between the measuring device and the pipe wall defect is within 100mm, accurate detection of defects with a length, width and depth of 10mm*10mm*5mm can be achieved.

[0026] In the pulse eddy current based pipeline defect measuring device described in the present invention, preferably, the number of turns of the detection wire 3 wound on the detection coil 1 is 40-60 turns, preferably 45-55 turns, and most preferably 50 turns; the number of turns of the excitation wire 4 wound on the excitation coil 2 is 15-35 turns, preferably 20-30 turns, and most preferably 25 turns.

[0027] In a further preferred embodiment, the ratio of the number of turns of the detection wire 3 wound on the detection coil 1 to the number of turns of the excitation wire 4 wound on the excitation coil 2 is 2:1.

[0028] In the present invention, by limiting the number of turns of the wire wound on the detection coil 1 and the excitation coil 2, and further specifically limiting the ratio of the number of turns of the detection wire 3 wound on the detection coil 1 to the number of turns of the excitation wire 4 wound on the excitation coil 2, in actual application, the detection accuracy of defects in the pipeline can be further effectively improved.

[0029] In the pulse eddy current based pipeline defect measuring device described in the present invention, preferably, the diameter of the detection coil 1 is 10-30 mm, preferably 15-25 mm, most preferably 20 mm, and the diameter of the excitation coil 2 is 20-40 mm, preferably 25-35 mm, most preferably 30 mm.

[0030] In a further preferred embodiment, the ratio of the diameter of the detection coil 1 to the diameter of the excitation coil 2 is 2:3.

[0031] In the present invention, by limiting the diameters of the detection coil 1 and the excitation coil 2, and further specifically limiting the ratio of the diameters of the detection coil 1 and the excitation coil 2, the detection accuracy of defects in the pipeline can be further effectively improved in actual application.

[0032] In the pulse eddy current based pipeline defect measuring device of the present invention, preferably, the height of the excitation coil 2 is 4-12 mm, preferably 8-10 mm, and most preferably 6 mm.

[0033] In the present invention, the height of the excitation coil 2 is experimentally verified, and a series of parameters such as 3mm, 6mm, and 9mm are specifically designed for the height of the excitation coil 2. Finally, it is verified through experiments that the detection sensitivity of the measuring device is reduced as the height of the excitation coil 2 increases. Further considering the actual situation, if the height of the excitation coil 2 is too small, the magnetic field intensity generated will be too small, so that the generated eddy current cannot penetrate thicker pipes and cannot effectively detect pipes with larger wall thicknesses. If the height of the excitation coil 2 is too large, the detection sensitivity will be reduced, and smaller defects cannot be effectively detected. Therefore, the present invention finally selects 6mm as the optimal height of the excitation coil 2, and the corresponding height of the detection coil 1 is 4-12mm at this time, and 6mm is most preferred.

[0034] In the pulsed eddy current based pipeline defect measuring device of the present invention, preferably, the frequency of the pulse current input by the alternating current source into the excitation wire 4 is 6-15 Hz, preferably 8-12 Hz, and most preferably 10 Hz.

[0035] In a further preferred embodiment, the pulse current is 0.5-1.5A, preferably 0.8-1.2A, and most preferably 1A.

[0036] In the present invention, for the frequency of the excitation signal, a series of frequencies are tested through experiments: 10Hz, 100Hz and 1000Hz, etc., and some related images are drawn according to the obtained detection signal, and it is verified that the greater the frequency, the lower the detection depth, and the voltage signal that can be induced by the detection coil 1 is reduced. In order to have a better detection effect, a lower excitation frequency should be selected for detection. However, in the actual detection process, a frequency that is too low will cause the power consumption of the coil to increase, and the detection time is too long. Therefore, when selecting the frequency, the frequency of the pulse current should be appropriately reduced while maintaining a certain detection efficiency and not damaging the detection equipment. Therefore, the most preferred frequency of the pulse current finally selected by the present invention is 10Hz. The size of the pulse current is further limited to 0.5-1.5A to ensure that the detection coil 1 can better receive the induced voltage.

[0037] In the pulsed eddy current based pipeline defect measuring device of the present invention, preferably, the detection coil 1 and the excitation coil 2 are both circular, so as to further improve the detection accuracy of pipeline defects.

[0038] In the pulsed eddy current based pipeline defect measuring device of the present invention, the displacement device 5 can be of various structures, as long as it can move the measuring device, so as to adjust the vertical height between the measuring device and the pipe wall as needed. In a specific embodiment, the displacement device 5 includes a fixed seat and a telescopic motor disposed on the fixed seat, and the telescopic motor drives the measuring device to move through a telescopic rod.

[0039] The working principle and implementation process of the present invention for obtaining the induced voltage based on the detection coil 1 are as follows: the excitation current is passed through the excitation wire 4 to the excitation coil 2, and the alternating pulse electric signal will establish an alternating excitation magnetic field space around it and act on the entire space, and a part of the magnetic field will diverge and act on the pipe wall of the pipeline. At the moment when the pulse signal has not been turned off, the magnetic field signal in the space maintains a stable state. When the pulse electric signal is instantly turned off and returns to zero in a short period of time, the metal pipe and the surrounding medium environment will still maintain an initial magnetic field environment at the moment when the excitation signal is disconnected. At the same time, the magnetic field signal acting on the pipe body will generate eddy currents. The magnetic field at this time is called the primary magnetic field; the primary magnetic field will decay rapidly, and at the same time, a time-varying induced eddy current will be generated inside the metal pipe. The induced eddy current will generate an alternating magnetic field space in the space, which is called the secondary magnetic field; then the detection coil 1 is used to receive the signal of the secondary magnetic field, and the received magnetic field signal is converted into a voltage signal, thereby obtaining the induced voltage.

[0040] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0041] Example 1 Use Figure 1-3 The pulsed eddy current based pipeline defect measuring device is implemented as shown, specifically, the pulsed eddy current based pipeline defect measuring device comprises a measuring device and a displacement device 5 for driving the measuring device to move; The measuring device comprises a detection coil 1 wound with a plurality of turns of detection wire 3 and an excitation coil 2 wound with a plurality of turns of excitation wire 4, wherein the detection coil 1 and the excitation coil 2 are coaxially arranged and the excitation coil 2 is arranged on the detection coil 1, and the excitation wire 4 is electrically connected to an alternating current source; Specifically, the detection coil 1 and the excitation coil 2 are both circular, and the displacement device 5 includes a fixing seat and a telescopic motor disposed on the fixing seat, and the telescopic motor drives the measuring device to move through a telescopic rod.

[0042] In actual application, step 1: wind a certain number of turns of wire around the excitation coil 2 and the detection coil 1 respectively, fix them coaxially, and integrate them on the pipeline internal detector 8 based on the fixing base; step 2: detect defects by configuring the internal detector 8, wherein a certain magnitude of alternating current is passed through the excitation coil 2; step 3: when the internal detector 8 moves along the inside of the pipeline 6, when there is no defect, the voltage signal obtained by the detection coil 1 is relatively flat without much fluctuation, but when the internal detector 8 passes through the defect 7 on the pipeline 6, the obtained voltage signal will have an obvious downward trend; step 4: according to the result obtained from step 3, the specific location of the defect can be obtained.

[0043] It has been tested that the pulse eddy current based pipeline defect measurement device described in the present invention can effectively improve the detection accuracy of small area defects in practical applications.

[0044] Example 2 The embodiment is implemented with reference to Example 1, except that the number of turns of the detection wire 3 wound on the detection coil 1 is 40-60 turns, and the number of turns of the excitation wire 4 wound on the excitation coil 2 is 15-35 turns; the ratio of the number of turns of the detection wire 3 wound on the detection coil 1 to the number of turns of the excitation wire 4 wound on the excitation coil 2 is 2:1; the diameter of the detection coil 1 is 10-30 mm, and the diameter of the excitation coil 2 is 20-40 mm; the ratio of the diameter of the detection coil 1 to the diameter of the excitation coil 2 is 2:3; the height of the excitation coil 2 is 4-12 mm.

[0045] Specifically, the number of turns of the detection wire 3 wound on the detection coil 1 is 50 turns, the number of turns of the excitation wire 4 wound on the excitation coil 2 is 25 turns, the diameter of the detection coil 1 is 20 mm, the diameter of the excitation coil 2 is 30 mm, and the height of the excitation coil 2 is 6 mm.

[0046] It has been tested that the pulse eddy current based pipeline defect measurement device described in the present invention can further effectively improve the detection accuracy of small area defects in practical applications.

[0047] Example 3 Refer to Example 2 for implementation, except that the frequency of the pulse current input by the alternating current source into the excitation wire 4 is 10 Hz, and the magnitude of the pulse current is 1A.

[0048] After testing, it is found that the pulse eddy current based pipeline defect measuring device described in the present invention can further effectively improve the detection accuracy of small area defects in actual application. Specifically, when the height difference between the measuring device and the pipe wall defect is within 100mm, accurate detection of defects with a length, width and depth of 10mm*10mm*5mm can be achieved.

[0049] The pulse eddy current-based pipeline defect measuring device provided by the present invention can greatly improve the detection accuracy of small-area defects in actual application by setting an eddy current-based measuring device for measuring defects in the pipeline. Specifically, when the height difference between the measuring device and the pipe wall defect is within 100 mm, accurate detection of defects with a length, width and depth of 10 mm*10 mm*5 mm can be achieved.

[0050] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A device for measuring defects in pipelines based on pulsed eddy current, characterized in that: The pulsed eddy current based pipeline defect measuring device comprises a measuring device and a displacement device (5) for driving the measuring device to move; The measuring device comprises a detection coil (1) wound with a plurality of turns of detection wire (3) and an excitation coil (2) wound with a plurality of turns of excitation wire (4), the detection coil (1) and the excitation coil (2) being coaxially arranged and the excitation coil (2) being arranged on the detection coil (1), and the excitation wire (4) being electrically connected to an alternating current source.

2. The device for measuring defects in pipelines based on pulsed eddy current according to claim 1, characterized in that: The number of turns of the detection wire (3) wound on the detection coil (1) is 40-60 turns, and the number of turns of the excitation wire (4) wound on the excitation coil (2) is 15-35 turns.

3. The device for measuring defects in pipelines based on pulsed eddy current according to claim 2, characterized in that: The ratio of the number of turns of the detection wire (3) wound on the detection coil (1) to the number of turns of the excitation wire (4) wound on the excitation coil (2) is 2:

1.

4. The device for measuring defects in pipelines based on pulsed eddy current according to any one of claims 1 to 3, characterized in that: The diameter of the detection coil (1) is 10-30 mm, and the diameter of the excitation coil (2) is 20-40 mm.

5. The device for measuring defects in pipelines based on pulsed eddy current according to claim 4, characterized in that: The ratio of the diameter of the detection coil (1) to the diameter of the excitation coil (2) is 2:

3.

6. The device for measuring defects in pipelines based on pulsed eddy current according to claim 1 or 5, characterized in that: The height of the excitation coil (2) is 4-12 mm.

7. The device for measuring defects in pipelines based on pulsed eddy current according to claim 1, characterized in that: The frequency of the pulse current inputted into the excitation wire (4) by the alternating current source is 6-15 Hz.

8. The device for measuring defects in pipelines based on pulsed eddy current according to claim 1 or 7, characterized in that: The magnitude of the pulse current is 0.5-1.5A.

9. The device for measuring defects in pipelines based on pulsed eddy current according to claim 1, characterized in that: The detection coil (1) and the excitation coil (2) are both circular.

10. The device for measuring defects in pipelines based on pulsed eddy current according to claim 1, characterized in that: The displacement device (5) comprises a fixing seat and a telescopic motor arranged on the fixing seat, and the telescopic motor drives the measuring device to move via a telescopic rod.

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