Pipeline leakage detection device and method

Abstract

The present invention relates to a pipeline leakage detection device and method, the pipeline leakage detection device comprises a metal powder storage box, a plurality of ribs and a signal acquisition and processing device, the metal powder storage box is annular, made of insulating material, used to be sleeved on a pipeline, and metal powder is stored inside, the inner peripheral wall and the outer peripheral wall are both mesh structures, and the mesh structure allows the metal powder to be ejected out of the metal powder storage box under the push of the leakage fluid of the pipeline; the plurality of ribs are made of insulating material, evenly distributed along the outer peripheral wall of the metal powder storage box, and respectively fixed on the metal powder storage box, and a plurality of coils arranged in a layer are configured inside; the signal acquisition and processing device connects each coil, is used to collect and monitor the electromagnetic signal of each coil, and obtains leakage parameters based on the abnormal signal when an abnormal signal occurs. The present invention can well detect whether the pipeline is leaking and obtain leakage parameters in the case of leakage, and is efficient, portable and accurate.

Description

Technical Field

[0001] The present invention relates to the field of pipeline leakage detection, and in particular to a pipeline leakage detection device and method. Background Art

[0002] my country is the world's largest developing country and also a major energy consumer. my country's energy consumption structure is still dominated by fossil energy consumption, and this situation will remain for some time. my country is at the forefront of the world in the utilization of gaseous and liquid energy such as oil and natural gas. With the improvement of people's living standards and social development and construction, people's demand for energy extraction and transportation is increasing. Pipeline transportation is an important mode of transportation. It has the advantages of high efficiency, stable operation and low cost. It has become the main mode of oil and gas transportation in various countries and regions. As a major oil and gas consumer, my country is also accelerating the construction of oil and gas transportation pipelines. The scale of long-distance pipeline construction and use is constantly increasing. Pipeline leakage has become a safety issue that needs to be urgently solved for oil and gas pipelines. The leakage problem exists in almost all links of oil and gas energy use, including production, transportation, and use, so it is a safety issue faced by almost everyone.

[0003] At present, there have been many serious safety accidents caused by oil and gas pipeline leakage, resulting in heavy casualties and property losses. Oil and gas pipeline leakage can cause environmental pollution, fire and even explosion, so whether pipeline leakage can be detected in a timely, efficient and accurate manner is of great significance.

[0004] Pipeline leak detection and location refers to the use of various technical principles and tools to detect the working conditions of transport pipelines. When a leak occurs in the transport pipeline, the leakage status of the pipeline can be accurately and quickly identified and the specific location of the leak point can be located, so that people can respond quickly to the leakage accident to avoid harm and loss.

[0005] Current pipeline leakage detection technologies can be roughly divided into three categories: hardware detection, manual inspection, and software detection. The more mainstream detection methods mainly use infrared, sound wave, and negative pressure detection to analyze leaks. Existing detection methods have the problems of cumbersome and complicated operation, long signal processing cycle, low efficiency, poor portability, and inaccurate detection. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a pipeline leakage detection device, which can well detect whether a pipeline is leaking and obtain leakage parameters when there is a leak, and is efficient, portable and accurate.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: a pipeline leakage detection device, comprising:

[0008] The metal powder storage box is annular, made of insulating material, and is used to be put on the pipeline. The metal powder is stored inside, and the inner and outer walls are both mesh structures. The mesh structure allows the metal powder to be ejected out of the metal powder storage box under the impetus of the leaking fluid of the pipeline;

[0009] A plurality of ribs, made of insulating material, are evenly distributed along the outer peripheral wall of the metal powder storage box and are respectively fixed on the metal powder storage box, and a plurality of coils arranged in a layer are arranged inside;

[0010] The signal acquisition and processing device is connected to each coil, and is used to acquire and monitor the electromagnetic signals of each coil, and obtain leakage parameters based on the abnormal signals when abnormal signals appear.

[0011] Furthermore, the coils in each rib plate form a coil plane, and each coil plane diverges along the radial direction of the metal powder storage box and is parallel to the axial direction of the metal powder storage box.

[0012] Furthermore, the leakage parameters include at least one of leakage velocity, leakage volume per unit time, leakage hole shape and leakage position.

[0013] The present invention also provides a pipeline leakage detection method, based on the pipeline leakage detection device, the method comprises:

[0014] Put the metal powder storage box on the pipeline to be inspected, move the metal powder storage box, and monitor the collected electromagnetic signals during the movement;

[0015] If an abnormal signal is detected, the source of the abnormal signal is confirmed. If the abnormal signal comes from interference, it is determined that there is no leakage in the detected pipeline. If the abnormal signal comes from pipeline leakage, the abnormal signal is analyzed and processed to obtain leakage parameters.

[0016] If no abnormal signal is detected, it is determined that there is no leakage in the detected pipeline.

[0017] Further, the confirming the source of the abnormal signal includes:

[0018] Repeatedly move and rotate the metal powder storage box in the pipe section where the abnormal signal appears;

[0019] If the abnormal signal disappears, it is determined that the abnormal signal comes from interference;

[0020] If the abnormal signal appears repeatedly, it is determined that the abnormal signal comes from pipeline leakage.

[0021] Furthermore, before the metal powder storage box is placed on the inspected pipeline, the method further includes:

[0022] Determine the size parameters of the pipeline leakage detection device according to the characteristics of the pipeline to be tested and the fluid inside the pipeline to be tested;

[0023] The electromagnetic parameters of the pipeline leakage detection device are determined according to the required accuracy of the pipeline being tested.

[0024] Further, the size parameters include the inner radius r2 of the metal powder storage box, the thickness h of the metal powder storage box, the rib width a1, the rib length b1, the rib thickness d and the angle β between adjacent ribs;

[0025] The electromagnetic parameters include current I, current frequency ω, current direction T, coil turns n, coil radius r1, metal magnetic permeability μ, electrical conductivity σ, the distance between adjacent coil centers a2 in the rib width direction, and the distance between adjacent coil centers b2 in the rib length direction.

[0026] Further, the leakage parameter includes a leakage rate, and the leakage rate is obtained by analyzing and processing the obtained abnormal signal, including:

[0027] According to the current data of the coil with abnormal signal changing with time, the time when a certain metal particle passes through the corresponding coil is obtained; wherein the certain metal particle is a particle in the metal powder sprayed out of the metal powder storage box and located in the laminar flow area;

[0028] Based on the distance between the centers of the corresponding coils and the time, the leakage rate is obtained.

[0029] Furthermore, the leakage parameters also include the leakage amount per unit time and the shape of the leakage hole. The abnormal signal obtained by analyzing and processing is used to obtain the leakage amount per unit time and the shape of the leakage hole, including:

[0030] Based on the abnormal signal caused by the turbulent area, the area A of the leakage hole is obtained;

[0031] According to Q = AV, calculate the leakage per unit time Q, where V is the leakage rate;

[0032] When the fluid in the pipeline is gas, according to Calculate the gas leakage coefficient, and obtain the shape of the leakage hole based on the gas leakage coefficient;

[0033] Among them, C d is the gas leakage coefficient, which is 1.00 for a circle, 0.95 for a triangle, and 0.90 for a rectangle; P is the fluid pressure in the pipeline; M is the relative molecular mass of the fluid transported in the pipeline; R g is the universal gas constant; t is the gas temperature; Y is the gas outflow coefficient, and the calculation formula is P is the gas pressure in the pipeline; P0 is the ambient pressure; γ is the adiabatic coefficient, which is a constant.

[0034] Further, the leakage parameter includes a leakage position, and the abnormal signal obtained by analysis and processing is obtained to obtain the leakage position, including:

[0035] First, move the metal powder storage box back and forth along the axial direction of the pipeline at the pipeline leakage section, and stop moving when the number of coils with abnormal signals reaches the maximum value;

[0036] Then the metal powder storage box is rotated, and when the change degrees of the coils in two adjacent ribs are the same, the rotation is stopped, and the midpoint of the area between the two adjacent ribs is the leakage position.

[0037] After adopting the above technical scheme, the present invention uses the leakage medium to cause the metal powder in the metal powder storage box to move in the same pattern as the leakage medium, causing the coil to generate an abnormal signal. The leakage state of the pipeline is analyzed by analyzing the abnormal signal caused by the movement of metal particles in the magnetic field. When used, the present invention has the advantages of high efficiency, portability and accuracy compared with existing detection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic structural diagram of a pipeline leakage device in an embodiment of the present invention;

[0039] Figure 2 It is a structural schematic diagram of a rib plate of a pipeline leakage device in an embodiment of the present invention;

[0040] Figure 3 It is a schematic structural diagram of a coil plane of a pipeline leakage device in an embodiment of the present invention;

[0041] Figure 4 It is a partial enlarged diagram of the working process of the pipeline leakage device in the embodiment of the present invention;

[0042] Figure 5 is a flow chart of a pipeline detection method in an embodiment of the present invention;

[0043] Figure 6 A working condition diagram of a pipeline leakage device in an embodiment of the present invention detecting a pipeline leakage;

[0044] Figure 7 is a current variation diagram of the coil I in the embodiment of the present invention;

[0045] Figure 8 is a current variation diagram of coil II in an embodiment of the present invention;

[0046] Fig. 9 is a current variation diagram of coil III in an embodiment of the present invention;

[0047] Fig.10A diagram showing a current change diagram of the coil I in an embodiment of the present invention in which a special current change is selected and the corresponding time is marked;

[0048] Fig.11 A diagram showing a current change diagram of coil II in an embodiment of the present invention in which a special current change is selected and the corresponding time is marked;

[0049] Fig.12 A diagram showing a current change diagram of coil III in an embodiment of the present invention in which a special current change is selected and the corresponding time is marked;

[0050] Fig.13 It is a schematic diagram of the analysis and calculation principle of the leakage amount per unit time and the shape of the leakage hole in the embodiment of the present invention;

[0051] Fig.14 This is a diagram showing changes in a pipeline leakage detection device that reciprocates along the axial direction of a pipeline in a pipeline leakage section according to an embodiment of the present invention;

[0052] Fig.15 This is a diagram showing changes when the pipeline leakage detection device is rotated at the pipeline leakage position in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0054] like Figure 1 , 2 , 3, and 4, a pipeline leakage detection device comprises:

[0055] The metal powder storage box 1 is annular and made of insulating material, and is used to be put on the pipe 2. The metal powder is stored inside, and the inner wall and the outer wall are both mesh structures. The mesh structure allows the metal powder to be ejected out of the metal powder storage box 1 under the impetus of the leakage fluid of the pipe 2;

[0056] A plurality of ribs 3, made of insulating material, are evenly distributed along the outer peripheral wall of the metal powder storage box 1 and are respectively fixed on the metal powder storage box 1, and a plurality of coils 4 arranged in a layer are arranged inside;

[0057] The signal acquisition and processing device is connected to each coil 4 and is used to acquire and monitor the electromagnetic signal of each coil 4, and obtain leakage parameters based on the abnormal signal when an abnormal signal occurs.

[0058] In this embodiment, the leakage parameters include at least one of leakage velocity, leakage volume per unit time, leakage hole shape and leakage position.

[0059] In this embodiment, the metal powder storage box 1 and the ribs are both made of insulating materials, which can avoid affecting the required magnetic field and detection results.

[0060] In this embodiment, the mesh structure allows the metal powder to be well stored in the metal powder storage box 1 without being pushed by the leaking fluid. After the metal powder in the metal powder storage box 1 is sprayed, metal powder can continue to be added to the metal powder storage box 1.

[0061] Specifically, this embodiment utilizes the leakage medium to cause the metal powder in the metal powder storage box 1 to move in the same pattern as the leakage medium, thereby causing the coil 4 to generate an abnormal signal. The leakage state of the pipeline 2 is analyzed by analyzing the abnormal signal caused by the movement of metal particles in the magnetic field. When used, the present invention has the advantages of high efficiency, portability and accuracy compared to existing detection devices.

[0062] like Figure 2 , 3 As shown, the coil 4 in each rib plate 3 forms a coil plane, and each coil plane diverges along the radial direction of the metal powder storage box 1 and is parallel to the axial direction of the metal powder storage box 1 .

[0063] like Figure 5 As shown, a pipeline leakage detection method is based on the above pipeline leakage detection device, and the method includes:

[0064] Put the metal powder storage box 1 on the pipeline 2 to be tested, and move the metal powder storage box 1, and monitor the collected electromagnetic signals during the movement;

[0065] If an abnormal signal is detected, the source of the abnormal signal is confirmed. If the abnormal signal comes from interference, it is determined that the detected pipeline 2 has no leakage. If the abnormal signal comes from a leakage in the pipeline 2, the abnormal signal is analyzed and processed to obtain leakage parameters.

[0066] If no abnormal signal is detected, it is determined that the detected pipeline 2 has no leakage.

[0067] In this embodiment, the step of confirming the source of the abnormal signal includes:

[0068] The metal powder storage box 1 is repeatedly moved and rotated in the pipe section of the pipeline 2 where the abnormal signal appears;

[0069] If the abnormal signal disappears, it is determined that the abnormal signal comes from interference;

[0070] If the abnormal signal appears repeatedly, it is determined that the abnormal signal comes from the leakage of pipeline 2.

[0071] In this embodiment, before the metal powder storage box 1 is put on the detected pipeline 2, the following steps are also included:

[0072] Determine the size parameters of the pipeline leakage detection device according to the characteristics of the pipeline 2 to be tested and the fluid inside the pipeline 2 to be tested;

[0073] The electromagnetic parameters of the pipeline leakage detection device are determined according to the required accuracy of the pipeline 2 to be tested.

[0074] In this embodiment, the size parameters include the inner radius r2 of the metal powder storage box 1 , the thickness h of the metal powder storage box 1 , the width a1 of the rib 3 , the length b1 of the rib 3 , the thickness d of the rib 3 and the angle β between adjacent ribs 3 .

[0075] Specifically, the inner radius r2 is affected by the outer diameter of the inspected pipe 2, and the inner radius r2 is equal to or slightly larger than the outer diameter of the inspected pipe 2; the thickness h is affected by the internal fluid characteristics, and the thickness h decreases with the increase of the viscosity coefficient of the internal fluid. When the fluid with a large viscosity coefficient moves, the original motion state is more easily affected. Therefore, the thickness h should be reduced to reduce the movement time of the fluid in the metal powder storage box 1; the size of the rib 3 is affected by the size of the inspected pipe 2 and the characteristics of the fluid, and the angle β between adjacent ribs 3 decreases with the increase of the size of the pipe 2, and the width a1 of the rib 3 should increase with the increase of the fluid pressure. The length b1 of the rib plate is affected by the size of the pipeline 2 to be tested and the actual testing needs. For example, the curvature of the pipeline 2 to be tested represents the bending degree of the pipeline 2. For large-scale pipelines 2, if the value of the length b1 of the rib plate 3 is too large, the device cannot completely fit the outer wall of the pipeline 2, and the device cannot be used normally; the values ​​of a1 and b1 jointly determine the number of coils 4 in the rib plate 3. The setting of the number of coils 4 is related to the detection accuracy. Therefore, the values ​​of a1 and b1 should also consider the needs of detection accuracy. The value of the thickness d of the rib plate 3 should be fixed; the coil is arranged inside the rib plate 3, and the thickness of the rib plate 3 should be reduced as much as possible to reduce the impact on the magnetic field strength and prevent the leaked fluid from changing its original motion state due to the influence of the rib plate 3.

[0076] In this embodiment, the electromagnetic parameters include current I, current frequency ω, current direction T, number of turns n of coil 4, radius r1 of coil 4, metal magnetic permeability μ, electrical conductivity σ, center distance a2 of adjacent coils 4 in the width direction of rib 3, and center distance b2 of adjacent coils 4 in the length direction of rib 3.

[0077] Specifically, after a1 and b1 are determined, the value of r1 determines the number of internal coils 4. The denser the arrangement of coils 4, the more accurate the detection result can be. The induced electromotive force of coil 4 is proportional to the number of coil turns n. The value of n affects the change of magnetic field strength. The current I, current frequency ω, n is the number of coil turns, metal magnetic permeability μ, and electrical conductivity σ, these parameters also affect the magnetic field of the device to detect leakage.

[0078] In this embodiment, the leakage parameter includes the leakage rate, and the leakage rate is obtained by analyzing and processing the obtained abnormal signal, including:

[0079] According to the current data of the coil 4 where the abnormal signal appears, the time when a certain metal particle passes through the corresponding coil 4 is obtained; wherein the certain metal particle is a particle in the metal powder sprayed out of the metal powder storage box 1 and located in the laminar flow area;

[0080] Based on the distance between the centers of the respective coils 4 and the time, the leakage velocity is obtained.

[0081] The calculation process of the leakage rate is described in detail below with reference to a specific example.

[0082] Figure 6 A leakage condition is demonstrated. A pipeline 2 leaks and the internal high-pressure fluid medium sprays out. During the spraying process, the metal powder in the metal powder storage box 1 moves with the fluid medium. The movement trajectory is as follows: Figure 6 As shown. At this time, it is considered that the movement characteristics of the metal powder are the same as the movement characteristics of the ejected fluid medium. During the movement of the metal powder in the laminar flow zone, the metal powder passes through the coil 4 arranged in a certain rib plate 3 in sequence.

[0083] The metal powder in the powder storage box 1 at the leakage point will move outward with the medium under the push of the leaking fluid medium. The movement law of the metal powder is the same as the dynamic law of the movement of the fluid medium when it leaks. The movement of the metal powder in the magnetic field between the ribs 3 causes eddy current inside the metal powder. The eddy current and the current of the coil 4 cause the original magnetic field to change due to the mutual induction phenomenon, resulting in the current of the coil 4 changing and generating an abnormal signal.

[0084] Tables 1, 2 and 3 list the changes in the current of three coils 4 located in the laminar flow area over time when the equipment is running under this condition. It is particularly pointed out that the number of coils 4 varies according to the actual working conditions. Here, three coils 4 can meet the calculation needs. The three coils 4 are sequentially recorded as coil I, coil II and coil III from the near pipeline side to the far pipeline side.

[0085] Table 1: Coil I current variation

[0086] Time t / μs CurrentI / mA Time t / μs CurrentI / mA Time t / μs CurrentI / mA 1 79.19789 42 79.23975 83 79.26162 2 79.21037 43 79.23224 84 79.2641 3 79.20286 44 79.23472 85 79.26658 4 79.21534 45 79.22721 86 79.26907 5 79.20783 46 79.22969 87 79.26155 6 79.21031 47 79.23217 88 79.26404 7 79.2128 48 79.24466 89 79.26652 8 79.20528 49 79.23714 90 79.26901 9 79.21776 50 79.23963 91 79.27149 10 79.22025 51 79.24211 92 79.27398 11 79.21273 52 79.2346 93 79.26646 12 79.22522 53 79.24708 94 79.26894 13 79.2177 54 79.24957 95 79.26143 14 79.23019 55 79.24205 96 79.27391 15 79.21267 56 79.23453 97 79.2664 16 79.21516 57 79.24702 98 79.26888 17 79.21764 58 79.2495 99 79.28137 18 79.22012 59 79.25199 100 79.27385 19 79.22261 60 79.25447 101 79.27634 20 79.21509 61 79.24696 102 79.27882 21 79.21758 62 79.24944 103 79.2713 22 79.22006 63 79.24193 104 79.27379 23 79.22255 64 79.24441 105 79.26627 24 79.22503 65 79.24689 106 79.27876 25 79.21752 66 79.24938 107 79.28124 26 79.23 67 79.25186 108 79.27373 27 79.22248 68 79.25435 109 79.27621 28 79.22497 69 79.24683 110 79.2687 29 79.22745 70 79.24932 111 79.27118 30 79.21994 71 79.2518 112 79.27367 31 79.22242 72 79.25429 113 79.28615 32 79.22491 73 79.25677 114 79.28863 33 79.22739 74 79.25926 115 79.28112 34 79.22988 75 79.26174 116 79.2836 35 79.22236 76 79.26422 117 79.28609 36 79.22485 77 79.26671 118 79.27857 37 79.23733 78 79.25919 119 79.28106 38 79.23981 79 79.26168 120 79.28354 39 79.2323 80 79.26416 121 79.28603 40 79.23478 81 79.26665 122 79.27851 41 79.23727 82 79.25913 …… ……

[0087] Table 2: Coil II current variation

[0088] Time t / μs CurrentI / mA Time t / μs CurrentI / mA Time t / μs CurrentI / mA 1 79.70894 42 79.56081 83 80.05621 2 79.66143 43 79.56329 84 80.0587 3 79.63391 44 79.56578 85 80.06118 4 79.6164 45 79.55826 86 80.06367 5 79.60888 46 79.56075 87 80.05615 6 79.64137 47 79.56323 88 80.06863 7 79.64385 48 79.56571 89 80.06112 8 79.60634 49 79.5582 90 80.0736 9 79.58882 50 79.56068 91 80.06609 10 79.5713 51 79.55317 92 80.05857 11 79.56379 52 79.56565 93 80.07106 12 79.55627 53 79.55814 94 80.06354 13 79.54876 54 79.55062 95 80.06603 14 79.54124 55 79.55311 96 80.06851 15 79.52373 56 79.55559 97 80.07099 16 79.52621 57 79.54808 98 80.06348 17 79.5287 58 79.55056 99 80.06596 18 79.53118 59 79.54304 100 80.06845 19 79.52367 60 79.54553 101 80.06093 20 79.52615 61 79.53801 102 80.06342 21 79.52863 62 79.5405 103 80.0659 22 79.54112 63 79.53298 104 80.05839 23 79.5436 64 79.53547 105 80.06087 24 79.53609 65 79.53795 106 80.05335 25 79.54857 66 79.54044 107 80.06584 26 79.55106 67 79.53292 108 80.06832 27 79.55354 68 79.5354 109 80.07081 28 79.54603 69 79.52789 110 80.06329 29 79.55851 70 79.52037 111 80.06578 30 79.55099 71 79.52286 112 80.06826 31 79.55348 72 79.52534 113 80.06075 32 79.55596 73 79.51783 114 80.06323 33 79.54845 74 79.52031 115 80.05571 34 79.55093 75 79.5128 116 80.0682 35 79.56342 76 79.51528 117 80.06068 36 79.5559 77 79.51776 118 80.06317 37 79.55839 78 79.52025 119 80.05565 38 79.56087 79 79.51273 120 80.05814 39 79.56335 80 79.50522 121 80.07062 40 79.56584 81 79.5077 122 80.06311 41 79.55832 82 79.51019 …… ……

[0089] Table 3: Coil III current variation

[0090] Time t / μs CurrentI / mA Time t / μs CurrentI / mA Time t / μs CurrentI / mA 1 80.07248 42 80.06435 83 80.05621 2 80.06497 43 80.06683 84 80.0587 3 80.06745 44 80.06932 85 80.06118 4 80.05994 45 80.0618 86 80.06367 5 80.06242 46 80.06429 87 80.05615 6 80.06491 47 80.06677 88 80.06863 7 80.05739 48 80.06926 89 80.06112 8 80.06988 49 80.06174 90 80.0736 9 80.06236 50 80.06422 91 80.06609 10 80.06485 51 80.06671 92 80.05857 11 80.06733 52 80.06919 93 80.07106 12 80.06981 53 80.06168 94 80.06354 13 80.0723 54 80.06416 95 80.06603 14 80.06478 55 80.05665 96 80.06851 15 80.06727 56 80.05913 97 80.07099 16 80.06975 57 80.06162 98 80.06348 17 80.07224 58 80.0741 99 80.06596 18 80.06472 59 80.06658 100 80.06845 19 80.06721 60 80.05907 101 80.06093 20 80.06969 61 80.06155 102 80.06342 21 80.07217 62 80.07404 103 80.0659 22 80.06466 63 80.06652 104 80.05839 23 80.06714 64 80.07901 105 80.06087 24 80.05963 65 80.06149 106 80.05335 25 80.07211 66 80.06398 107 80.06584 26 80.0646 67 80.06646 108 80.06832 27 80.07708 68 80.05894 109 80.07081 28 80.06957 69 80.06143 110 80.06329 29 80.06205 70 80.06391 111 80.06578 30 80.06453 71 80.0764 112 80.06826 31 80.06702 72 80.06888 113 80.06075 32 80.0595 73 80.07137 114 80.06323 33 80.06199 74 80.06385 115 80.05571 34 80.06447 75 80.06634 116 80.0682 35 80.05696 76 80.06882 117 80.06068 36 80.06944 77 80.0613 118 80.06317 37 80.06193 78 80.05379 119 80.05565 38 80.06441 79 80.06627 120 80.05814 39 80.06689 80 80.05876 121 80.07062 40 80.05938 81 80.07124 122 80.06311 41 80.06186 82 80.06373 …… ……

[0091] In order to intuitively show the change of the current of coil 4, the data in the above three tables are plotted into a graph. Figure 7 is the current variation diagram of coil I, Figure 8 is the current variation diagram of coil II, Fig. 9 The current change diagram of coil III is shown in Figure 2. Compared with the current of coil 4 when no leakage is detected, when metal particles move on the side of coil 4, the current will fluctuate due to the change of magnetic field. By analyzing the fluctuation, the movement state of the metal particles can be obtained, and the current leakage situation can be inferred.

[0092] The same metal particle will pass through the coil 4 on the motion track in sequence, so the same metal particle will have similar effects on the magnetic field of the coil 4 on the motion track. Figure 7 , Figure 8 , Fig. 9 Analysis shows that the metal particles' movement in the magnetic field affects the magnetic field of coil 4, and the direct reaction is the impact on the current of coil 4. Figure 7 , Figure 8 , Fig. 9 By analyzing the fluctuations on the curve and combining factors such as the rate of change, peak value, and period of the curve, it is believed that the waveforms with the same characteristics in the current changes of different coils are caused by the movement of the same particle.

[0093] Combined with the relative distance position of coil 4 on rib 3 and the time when waveforms with the same characteristics appear on different coils, we follow Calculate the velocity of the particle.

[0094] Among them, ΔL is the distance between the centers of the two coils 4; Δt is the time to sequentially pass through the distance between the centers of the two coils 4; v is the speed of the metal particles between the distances between the centers of the two coils 4. The more coils 4 are arranged on the ribs 3 of the same size, the higher the accuracy of the obtained data.

[0095] Combination Figure 7 , Figure 8 and Fig. 9 It can be concluded that the same metal particle will cause fluctuations with the same characteristics when passing through different coils 4. Fig.10 A diagram showing a current change diagram of the coil I in an embodiment of the present invention in which a special current change is selected and the corresponding time is marked; Fig.11 A diagram showing a current change diagram of coil II in an embodiment of the present invention in which a special current change is selected and the corresponding time is marked; Fig.12 The diagram is a diagram of the current variation of coil III in the embodiment of the present invention, in which a special current variation is selected and the corresponding time is marked. Fig.10 , Fig.11 and Fig.12 The similar waveforms and corresponding moments selected for this calculation are shown.

[0096] like Figure 6 As shown, L1 is the center distance between coil I and coil II, L2 is the center distance between coil II and coil III, and L1+L2 is the center distance between coil II and coil III, which can all be obtained by measurement.

[0097] Table 4: Center positions of three coils 4 and center distance between two coils 4

[0098]

[0099] Table 5: The time when the metal particles pass through the center of the coil 4 and the time taken to pass the distance between the centers of the two coils 4

[0100]

[0101] After calculation, the speed of metal particle movement can be obtained, as shown in Table 6.

[0102] Table 6: Speed ​​of metal particles passing through different coil center distances

[0103]

[0104] It can be seen that the speed of the metal particles within the center distance between coils I and II is 26.585m / s; the speed within the center distance between coils II and III is 25.946m / s; the speed within the center distance between coils 1 and III is 26.265m / s. Because the speed of the metal particles is consistent with the speed of the fluid medium due to leakage, the leakage speed takes the average of the above three speeds, and the pipeline leakage speed V is 26.265m / s.

[0105] In this embodiment, the leakage parameters also include the leakage amount per unit time and the shape of the leakage hole. The abnormal signal obtained by analyzing and processing to obtain the leakage amount per unit time and the shape of the leakage hole includes:

[0106] Based on the abnormal signal caused by the turbulent area, the area A of the leakage hole is obtained;

[0107] According to Q = AV, calculate the leakage per unit time Q;

[0108] When the fluid in the pipeline 2 is gas, according to Calculate the gas leakage coefficient, and obtain the shape of the leakage hole based on the gas leakage coefficient;

[0109] Among them, C d is the gas leakage coefficient, which is 1.00 for a circle, 0.95 for a triangle, and 0.90 for a rectangle; P is the fluid pressure in pipe 2; M is the relative molecular mass of the fluid transported in the pipe; R gis the universal gas constant; t is the gas temperature; Y is the gas outflow coefficient, and the calculation formula is P is the gas pressure in pipeline 2; P0 is the ambient pressure; γ is the adiabatic coefficient, which is a constant.

[0110] In this embodiment, for the fluid in the pipeline 2, if the fluid is gas, the gas may cause different consequences through different leakage hole shapes, so it is necessary to roughly judge the leakage hole shape. However, if the fluid in the pipeline 2 is liquid, it is usually not necessary to consider.

[0111] In this embodiment, when the fluid in the pipeline 2 is gas, the calculated C d The value is compared with the three values ​​of 1.00, 0.95 and 0.90. The value that the value is closer to can roughly determine the shape corresponding to which value the shape of the leakage hole is closer to, thereby determining the possible consequences of the leakage hole of this shape.

[0112] In this embodiment, if the fluid transported in the pipeline 2 is a mixed gas, the C corresponding to each gas is first calculated. d value, and then calculate the final C according to the proportion of various gases in the mixed gas and the corresponding weights. d value, with the final C d The value is used to determine the shape of the leak hole.

[0113] Specifically, Fig.13 The schematic diagram of the analysis and calculation of the leakage volume per unit time and the shape of the leakage hole shows that the fluid medium is ejected from the leakage point of the pipeline 2, and the metal powder in the metal powder storage box 1 moves between the ribs 3 with the same movement characteristics as the fluid medium. The fluid medium ejected from the center of the leakage point will be less affected by the outside world, so it can maintain laminar flow at a longer distance, such as Fig.13 In the laminar flow area 5 shown in the figure, the flow state of the fluid medium in this part is close to the motion state of the leaking part, so the metal powder in this area is used to calculate the leakage rate of the pipeline. At the same time, the fluid medium around the laminar flow area 5 is easily affected by the outside world during the outward spraying process, and the original motion state cannot be maintained continuously due to the disturbance. According to the knowledge of fluid mechanics, a Fig.13 The turbulence phenomena shown in Fig.13In the turbulent zone 6 shown in the figure, when turbulence is formed, the coil 4 on the side of the turbulent zone 6 is affected by the metal particles that maintain the same motion state as the fluid medium in the turbulent zone 6, and an abnormal signal will be generated. By analyzing the abnormal signal, the degree of turbulence in the medium between the ribs 3 can be obtained. The determining factors of the degree of turbulence are the leakage velocity at the leakage point, the area of ​​the leakage hole, and the density of the external medium. By analyzing the abnormal signal generated by the turbulence between the ribs 3, we can obtain the area A of the leakage hole, and then calculate the leakage per unit time Q at the leakage point of the pipeline 2. When the present device analyzes and calculates the pipeline leakage, it is equivalent to a circular leakage hole, and then the shape of the leakage hole is further analyzed based on the leakage per unit time Q.

[0114] Depend on,

[0115] get,

[0116] In this embodiment, the leakage parameter includes the leakage position, and the abnormal signal obtained by analysis and processing to obtain the leakage position includes:

[0117] First, the metal powder storage box 1 is reciprocated along the axial direction of the pipeline 2 at the leakage section of the pipeline 2, and the movement is stopped when the number of coils 4 with abnormal signals reaches the maximum value;

[0118] Then, the metal powder storage box 1 is rotated, and when the change degrees of the coils 4 in two adjacent ribs 3 are the same, the rotation is stopped, and the midpoint of the area between the two adjacent ribs 3 is the leakage position.

[0119] Specifically, after determining that the abnormal signal comes from a pipeline leak, the pipeline leak detection device is reciprocated along the axial direction of the pipeline 2 at the leaking section of the pipeline 2. When the moving rib passes through the pipeline leak, it will pass through Fig.14 In the three processes shown in FIG, when the movement reaches the moment t1, the current of the coil 4 in the corresponding rib plate 3 will have an abnormal signal, and when the middle position of the rib plate 3 passes the leakage point, the number of coils 4 with abnormal signals will reach the maximum value, that is, Fig.14 In the case shown at time t2, if the rib plate 3 continues to move, the number of coils 4 generating abnormal signals will decrease, that is, Fig.14 Therefore, when the device moves to the position at time t2, the leakage position is on the circumference of the line connecting the midpoints of the bottom of the rib 3.

[0120] After determining the leak location within the 2nd circumference of the pipeline, if Fig.15 As shown, the specific position of the leakage position on the circumference can be determined. The specific principle is as follows:

[0121] according to Fig.15Rotate the device as shown in the figure. The position of the leak point will experience three moments t`1, t`2, and t`3 in sequence. When rotating the device, the change of current should be observed at the same time. When the device moves to the moment t`2, the change of the current of the coil 4 on the two ribs 3 on both sides of the leak point should be the same, that is, the device is in Fig.15 At the middle t`2 position, the leakage point is at the midpoint of the part of the circle passing through the two ribs 3.

[0122] This will allow us to determine the exact location of the leak. Fig.14 T2 and Fig.15 At the position shown at time t`2, the leakage point is located at the midpoint of the area between the roots of the two ribs 3 shown.

[0123] This embodiment can accurately and conveniently obtain the leakage velocity, leakage volume per unit time, leakage hole shape and leakage position, and has precise positioning.

[0124] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A pipeline leakage detection device, characterized in that: include: The metal powder storage box (1) is annular and made of insulating material, and is used to be sleeved on the pipeline (2). The metal powder is stored inside, and the inner wall and the outer wall are both mesh structures. The mesh structure allows the metal powder to be ejected out of the metal powder storage box (1) under the impetus of the leaking fluid of the pipeline (2); A plurality of ribs (3) are made of insulating material and are evenly distributed along the outer peripheral wall of the metal powder storage box (1) and are respectively fixed on the metal powder storage box (1), and a plurality of coils (4) arranged in a layer are arranged inside the box; The signal acquisition and processing device is connected to each coil (4) and is used to acquire and monitor the electromagnetic signal of each coil (4), and to obtain leakage parameters based on the abnormal signal when an abnormal signal occurs.

2. The pipeline leakage detection device according to claim 1, characterized in that: The coil (4) in each rib plate (3) forms a coil plane, and each coil plane diverges along the radial direction of the metal powder storage box (1) and is parallel to the axial direction of the metal powder storage box (1).

3. The pipeline leakage detection device according to claim 1, characterized in that: The leakage parameters include at least one of leakage velocity, leakage volume per unit time, leakage hole shape and leakage position.

4. A pipeline leakage detection method, characterized in that: Based on the pipeline leakage detection device according to any one of claims 1 to 3, the method comprises: Putting a metal powder storage box (1) on the pipeline (2) to be inspected, and moving the metal powder storage box (1), and monitoring the collected electromagnetic signals during the movement; If an abnormal signal is detected, the source of the abnormal signal is confirmed; if the abnormal signal is caused by interference, it is determined that the detected pipeline (2) has no leakage; if the abnormal signal is caused by leakage of the pipeline (2), the abnormal signal is analyzed and processed to obtain leakage parameters; If no abnormal signal is detected, it is determined that the detected pipeline (2) has no leakage.

5. The pipeline leakage detection method according to claim 4, characterized in that: The confirming the source of the abnormal signal comprises: Repeatedly moving and rotating the metal powder storage box (1) in the pipe section of the pipeline (2) where the abnormal signal appears; If the abnormal signal disappears, it is determined that the abnormal signal comes from interference; If the abnormal signal appears repeatedly, it is determined that the abnormal signal comes from a leak in the pipeline (2).

6. The pipeline leakage detection method according to claim 4, characterized in that: Before the metal powder storage box (1) is placed on the pipeline (2) to be inspected, the method further comprises: Determining the size parameters of the pipeline leakage detection device according to the characteristics of the pipeline (2) to be tested and the fluid inside the pipeline (2); The electromagnetic parameters of the pipeline leakage detection device are determined according to the accuracy required by the pipeline (2) to be tested.

7. The pipeline leakage detection method according to claim 6, characterized in that: The size parameters include the inner radius r2 of the metal powder storage box (1), the thickness h of the metal powder storage box (1), the width a1 of the ribs (3), the length b1 of the ribs (3), the thickness d of the ribs (3), and the angle β between adjacent ribs (3); The electromagnetic parameters include current I, current frequency ω, current direction T, number of turns n of the coil (4), radius r1 of the coil (4), metal magnetic permeability μ, electrical conductivity σ, distance a2 between the centers of adjacent coils (4) in the width direction of the rib plate (3), and distance b2 between the centers of adjacent coils (4) in the length direction of the rib plate (3).

8. The pipeline leakage detection method according to claim 4, characterized in that: The leakage parameter includes a leakage rate, and the leakage rate is obtained by analyzing and processing the abnormal signal, including: The time at which a certain metal particle passes through the corresponding coil (4) is obtained based on the current data of the coil (4) that generates the abnormal signal and changes with time; wherein the certain metal particle is a particle in the metal powder that is ejected from the metal powder storage box (1) and is located in the laminar flow area; Based on the distance between the centers of the corresponding coils (4) and the time, the leakage rate is obtained.

9. The pipeline leakage detection method according to claim 8, characterized in that: The leakage parameters also include the leakage amount per unit time and the shape of the leakage hole. The abnormal signal obtained by analyzing and processing the leakage amount per unit time and the shape of the leakage hole include: Based on the abnormal signal caused by the turbulent area, the area A of the leakage hole is obtained; According to Q = AV, calculate the leakage per unit time Q, where V is the leakage rate; When the fluid in the pipe (2) is gas, according to Calculate the gas leakage coefficient, and obtain the shape of the leakage hole based on the gas leakage coefficient; Among them, C d is the gas leakage coefficient, which is 1.00 for a circle, 0.95 for a triangle, and 0.90 for a rectangle; P is the fluid pressure in the pipeline (2); M is the relative molecular mass of the fluid transported in the pipeline; R g is the universal gas constant; t is the gas temperature; Y is the gas outflow coefficient, and the calculation formula is P is the gas pressure in the pipeline (2); P0 is the ambient pressure; γ is the adiabatic coefficient, which is a constant.

10. The pipeline leakage detection method according to claim 4, characterized in that: The leakage parameters include the leakage location, and the abnormal signal obtained by analyzing and processing to obtain the leakage location includes: First, the metal powder storage box (1) is reciprocated along the axial direction of the pipeline (2) at the leakage section of the pipeline (2), and the movement is stopped when the number of coils (4) with abnormal signals reaches a maximum value; The metal powder storage box (1) is then rotated, and when the extent of change of the coils (4) in two adjacent ribs (3) is the same, the rotation is stopped, and the midpoint of the area between the two adjacent ribs (3) is the leakage position.

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