WO2016197972A1

WO2016197972A1 - Method, device and apparatus for detecting pipeline defect

Info

Publication number: WO2016197972A1
Application number: PCT/CN2016/085425
Authority: WO
Inventors: 于润桥; 张斌; 胡博; 夏桂锁; 程东方; 程强强
Original assignee: 宁波市鄞州磁泰电子科技有限公司
Priority date: 2015-06-12
Filing date: 2016-06-12
Publication date: 2016-12-15
Also published as: CA2952294C; CA2952294A1

Abstract

Provided are a method, device and apparatus for detecting a pipeline defect. A method for detecting a pipeline defect can accurately detect a position and a extent of the pipeline defect, and specifically comprises: detecting, along a length direction of a pipeline, a first parameter related to a magnetic flux density; determining whether the first parameter exceeds a preset threshold; determining a position where the first parameter exceeds the preset threshold as a position of the pipeline defect; and determining a extent of the pipeline defect on the basis of a value of the first parameter exceeding the preset threshold.

Description

Pipeline defect detecting method, pipe defect detecting device and pipe defect detecting device

Technical field

The invention relates to the field of detection technology, in particular to a pipeline defect detecting method, a pipeline defect detecting device and a pipeline defect detecting device.

Background technique

With the advancement of science and technology and the needs of industrial production, the use of transportation pipelines has become increasingly widespread. Long-distance transportation pipelines are the main mode of transportation for oil and gas industry products. Moreover, if there is a leak such as a leak in the long-distance transportation pipeline of oil and gas, in addition to the loss caused by outage and repair, it will also cause pollution. Therefore, how to ensure the safe operation of existing oil and gas long-distance transportation pipelines and new pipelines, reduce the probability of reducing safety accidents, and realize the intrinsic safety of pipeline operation is an urgent task to ensure the safe operation of pipelines.

Since oil and gas long-distance transportation pipelines are usually buried underground, the main work flow for detecting such buried pipeline defects is still: excavation, stripping of anti-corrosion (insulation) layer, detection, coating, and backfilling. Obviously, this is a destructive test method, and the representativeness of the test data and the reliability of the evaluation results are affected by the number of excavation (sampling) points and their distribution range. Therefore, the detection of buried pipelines without excavation and non-stopping becomes a problem worthy of further discussion.

There are various methods for non-destructive testing in the prior art, including ultrasonic testing, eddy current testing, and radiation testing. Ultrasonic testing is realized by the information provided by the interaction of ultrasonic waves and objects. The sound wave can propagate in the metal. The disadvantage of this method is that the ultrasonic wave decays rapidly in the air. Generally, there is a sound wave propagation medium when detecting. Coupling agents such as oil or water are not suitable for the detection of buried pipelines.

Radiographic detection is a non-destructive testing method that uses physical effects (such as changes in radiant intensity, scattering, etc.) generated by the interaction between ionizing radiation and matter to detect discontinuities, structures, or thicknesses within the workpiece. The same applies to the detection of buried pipelines.

The eddy current test method works on the principle of electromagnetic induction, so the eddy current test method can detect the surface of the workpiece. Defects and near surface defects. The remarkable feature of the eddy current testing method is that it acts on the conductive material, not necessarily the ferromagnetic material, but the effect on the ferromagnetic material is poor. Secondly, the surface smoothness, flatness and edge of the workpiece to be inspected have a great influence on the eddy current. Therefore, the eddy current testing method is often used for the detection of non-ferromagnetic workpieces such as copper tubes with regular shapes and smooth surfaces. If the buried pipeline is a ferromagnetic pipeline, the eddy current detection method cannot be realized, and the eddy current detection method also requires an excitation source, and the excavation is still required to detect the buried pipeline.

The invention patent application with the publication number CN102095080A discloses a non-excavation magnetic detection method for a buried pipeline, the principle of which is to utilize the magnetic property of the buried pipeline itself magnetized by the earth magnetic field as the excitation source, and utilize the magnetic induction intensity. A fluxgate sensor with a resolution of 1nT measures the magnetic induction and attenuation above the bottom surface, and simultaneously extends the detection result, and then uses the data processing to detect the quality of the pipeline. However, the document does not specifically disclose how to detect the defects of the buried pipeline, and it is impossible to judge the location of the defect of the buried pipeline and the size of the defect.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art, and to provide a pipe defect detecting method, a pipe defect detecting device and a pipe defect detecting device capable of accurately detecting a defect position and a defect size on a pipe.

In order to solve the above technical problem, an aspect of the present invention provides a pipeline defect detecting method, including: detecting a first parameter related to a magnetic induction intensity along a length direction of the pipeline; determining whether the first parameter exceeds a predetermined threshold; The position at which the first parameter exceeds a predetermined threshold is determined as a defect position of the pipe; and the degree of defect of the pipe is determined based on a value of the first parameter exceeding a predetermined threshold.

In the above pipe defect detecting method, the first parameter is a rate of change of a component of the magnetic induction in a first direction in a three-dimensional coordinate system in a second direction.

In the above pipe defect detecting method, the first direction is the same as the second direction, or the first direction is different from the second direction.

In the above pipeline defect detecting method, determining the degree of defect of the pipeline based on the value of the first parameter exceeding a predetermined threshold value specifically includes: determining a defect size of the pipeline based on an amplitude of the first parameter exceeding a predetermined threshold; and/or based on The length of the first parameter continuously exceeding a predetermined threshold determines the defect length of the pipe.

In the above pipe defect detecting method, the method further includes: plotting a magnitude of the amplitude value of the first parameter with respect to a distance in a length direction of the pipe.

In the above pipeline defect detecting method, the method further includes: detecting a second parameter related to the magnetic induction intensity along a length direction of the pipeline; determining whether the second parameter exceeds a predetermined threshold; determining a position at which the second parameter exceeds a predetermined threshold a defect location of the pipe; and a defect level of the pipe based on the value of the second parameter exceeding a predetermined threshold.

In the above pipe defect detecting method, when the position where the first parameter exceeds the predetermined threshold is the same position as the position where the second parameter exceeds the predetermined threshold, the value of the first parameter based on exceeding the predetermined threshold exceeds a predetermined value The value of the second parameter of the threshold determines the degree of defect in the pipe.

In the above pipe defect detecting method, the second parameter is a rate of change of a component of the third-order direction of the magnetic induction in the three-dimensional coordinate system in the fourth direction.

In the above pipe defect detecting method, the third direction is the same as the fourth direction, or the third direction is different from the fourth direction.

In the above pipe defect detecting method, the first direction, the second direction, the third direction, and the fourth direction are one of an x direction, a y direction, and a z direction in a three-dimensional coordinate system.

In the above method for detecting a pipeline defect, the method for determining whether the first parameter exceeds a predetermined threshold comprises: performing differential processing on the first parameter; adding or subtracting an average value of n times of the first parameter after the differential processing The variance is taken as a predetermined threshold, where 1 ≤ n ≤ 3; it is determined whether the first parameter exceeds a predetermined threshold.

In the above pipeline defect detecting method, determining whether the first parameter exceeds a predetermined threshold further comprises: detecting, in the absence of the pipeline to be detected, a third parameter related to the magnetic induction intensity along a length direction of the pipeline, wherein the third parameter The parameter is the same parameter as the first parameter; and in the case that the first parameter is greater than the third parameter, the first parameter is optimized with a third parameter, and it is determined whether the optimized first parameter is Exceeded the predetermined threshold.

In the above pipeline defect detecting method, the method further includes: in addition to the first parameter and the second parameter related to the magnetic induction intensity, further detecting the magnetic induction intensity in the three reference directions in the three-dimensional coordinate system along the length direction of the pipe The components H _x , H _y , H _z are respectively changed in the three directions x, y, z of the coordinate system to form a magnetic gradient matrix G comprising a total of nine elements:

Another aspect of the present invention provides a pipe defect detecting apparatus, comprising: a detecting unit configured to detect a first parameter related to a magnetic induction intensity along a length direction of the pipe; and a determining unit configured to determine whether the first parameter is And exceeding a predetermined threshold; and a control unit configured to determine a position at which the first parameter exceeds a predetermined threshold as a defect position of the pipe, and determine a degree of defect of the pipe based on a value of the first parameter exceeding a predetermined threshold.

In the above pipe defect detecting device, the first parameter is a rate of change of a component of the magnetic induction in a first direction in a three-dimensional coordinate system in a second direction.

In the above pipe defect detecting device, the first direction is the same as the second direction, or the first direction is different from the second direction.

In the above pipe defect detecting apparatus, the control unit further includes: a defect size determining module configured to determine a defect size of the pipe based on an amplitude of the first parameter exceeding a predetermined threshold; and/or a defect length determining module configured to be based on the The length of the first parameter continuously exceeding a predetermined threshold determines the defect length of the pipe.

In the above-described pipe defect detecting device, further comprising a drawing unit configured to draw a graph of the amplitude value of the first parameter with respect to the distance in the longitudinal direction of the pipe based on the first parameter detected by the detecting unit.

In the above pipe defect detecting device, the detecting unit is further configured to detect a second parameter related to the magnetic induction intensity along a length direction of the pipe; the determining unit is further configured to determine whether the second parameter exceeds a predetermined threshold; and The control unit is further configured to determine a position at which the second parameter exceeds a predetermined threshold as a defect position of the pipe, and determine a degree of defect of the pipe based on a value of the second parameter exceeding a predetermined threshold.

In the above pipe defect detecting device, the control unit is based on the first parameter exceeding a predetermined threshold when determining that the position where the first parameter exceeds a predetermined threshold and the position where the second parameter exceeds a predetermined threshold are the same position The value of the second parameter and the value of the second parameter exceeding a predetermined threshold determine the degree of defect in the pipe.

In the above pipe defect detecting device, the second parameter is the magnetic induction intensity in a three-dimensional coordinate system The rate of change of the component in the third direction in the third direction.

In the above pipe defect detecting device, the third direction is the same as the fourth direction, or the third direction is different from the fourth direction.

In the above pipe defect detecting device, the first direction, the second direction, the third direction, and the fourth direction are one of an x direction, a y direction, and a z direction in a three-dimensional coordinate system.

In the above pipeline defect detecting apparatus, the determining unit further includes: a differential processing module configured to perform differential processing on the first parameter; and an arithmetic processing module configured to be first after the differential processing by the differential processing module The amplitude mean of the parameter is added or subtracted by n times as a predetermined threshold, wherein 1≤n≤3; and the determining module is configured to determine whether the first parameter exceeds a predetermined threshold.

In the above pipe defect detecting device, the detecting unit is further configured to detect a third parameter related to the magnetic induction intensity along the length direction of the pipe in the absence of the pipe to be detected, wherein the third parameter is the first parameter The same parameter; and, the determining unit is further configured to optimize the first parameter with a third parameter and determine the first of the optimization if the first parameter is greater than the third parameter Whether the parameter exceeds a predetermined threshold.

In the above pipe defect detecting device, the detecting unit is further configured to detect three reference directions of the magnetic induction in the three-dimensional coordinate system along the length direction of the pipe in addition to the first parameter and the second parameter related to the magnetic induction intensity The upper three components H _x , H _y , and H _z are respectively changed in the three directions x, y, and z of the coordinate system to form a magnetic gradient matrix G including a total of nine elements:

In the above-described pipe defect detecting device, the detecting unit specifically includes a first three-component magnetic detecting sensor, and a second three-component magnetic detecting sensor symmetrically arranged with the first three-component magnetic detecting sensor at the center of the detecting unit a third three-component magnetic detecting sensor and a fourth three-component magnetic detecting sensor symmetrically arranged with the third three-component magnetic detecting sensor at a center of the detecting unit, wherein the first, second, third and fourth The three-component magnetic sensor is arranged in a cross on one plane; each of the first, second, third and fourth three-component magnetic sensors detects three of its three-dimensional coordinate systems The magnetic induction value in the reference direction is used to calculate the magnetic field gradient at the center of the cross, thereby measuring the magnetic field gradient matrix G of the center of the cross:

Where Δx is the distance between the first three-component magnetic sensor and the second three-component magnetic sensor, and Δz is between the third three-component magnetic sensor and the fourth three-component magnetic sensor. Distance, B _1x is the magnetic induction component of the x direction measured by the first three-component magnetic sensor, and B _1y is the magnetic induction component of the y direction measured by the first three-component magnetic sensor, and B _1z is the first three The magnetic induction component of the z direction measured by the component magnetic sensor, B _2x is the magnetic induction component of the x direction measured by the second three component magnetic sensor, and B _2y is measured by the second three component magnetic sensor The magnetic induction component of the y direction, B _2z is the magnetic induction component of the z direction measured by the second three component magnetic sensor, and B _0x is the magnetic induction component of the x direction measured by the third three component magnetic sensor, B _0y is the magnetic induction component of the y direction measured by the third three-component magnetic sensor, B _0z is the magnetic induction component of the z direction measured by the third three component magnetic sensor, and B _2x is the fourth three component measurement. component of the magnetic induction measured in the x-direction magnetic sensors, B _2y fourth Y-direction component of the magnetic induction of the magnetic sensor sensing component measured magnetic flux density component _2z z direction is a fourth three-component magnetic measurement measured by the sensor B.

Yet another aspect of the present invention provides a pipe defect detecting apparatus comprising: a shelf placed above a pipe to be inspected; a sliding track disposed on the shelf and slidable along a length of the shelf; The defect detecting device is slidably coupled to the sliding track by a slider to detect a pipe defect of the pipe to be detected.

In the above pipe defect detecting apparatus, further comprising an actuating means for causing the pipe defect to slide at a uniform speed on the sliding track.

In the above pipe defect detecting apparatus, the actuating means employs an actuating mode including any one of manpower, air pressure, and hydraulic pressure.

According to the pipe defect detecting method, the pipe defect detecting device and the pipe defect detecting device of the present invention, it is possible to determine whether the pipe has a defect based on a parameter related to the magnetic induction strength, and to determine the defect position of the pipe according to the abnormal position of the parameter, and The degree of defect of the pipe is determined based on the value of the parameter having the abnormality. In this way, the position of defects and the degree of defects on the pipe can be accurately detected.

DRAWINGS

1 is a schematic flow chart showing a pipe defect detecting method according to a first embodiment of the present invention;

2 is a schematic diagram of a graph drawn by detecting five elements of a magnetic gradient matrix;

3 is a schematic diagram of a curve obtained by performing differential processing on a curve in FIG. 2;

4 is a schematic view showing an abnormal region after the five curves shown in FIG. 2 are processed;

FIG. 5 is a schematic diagram of the abnormal region shown after the processing shown in FIG. 4 is integrated; FIG.

6 is a schematic view of a pipe defect made based on the integrated abnormal region shown in FIG. 5;

Figure 7 is a schematic block diagram illustrating a pipe defect detecting device according to a second embodiment of the present invention;

Figure 8 is a schematic illustration of a magnetic field gradient detecting component in accordance with an embodiment of the present invention;

Fig. 9 is a schematic view showing a pipe defect detecting apparatus according to a third embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

According to a first embodiment of the present invention, there is provided a pipeline defect detecting method comprising the steps of: detecting a first parameter related to a magnetic induction intensity along a length direction of the pipeline; determining whether the first parameter exceeds a predetermined threshold; The position at which the first parameter exceeds a predetermined threshold is determined as a defect position of the pipe; and the degree of defect of the pipe is determined based on a value of the first parameter exceeding a predetermined threshold.

With the pipe defect detecting method according to the first embodiment of the present invention, it is possible to judge whether or not the pipe has a defect based on the first parameter related to the magnetic induction intensity, and further, the defect position of the pipe can be determined according to the position at which the parameter exceeds the predetermined threshold value And determining the degree of defect of the pipe based on the value of the parameter exceeding a predetermined threshold. Thus, the pipe defect detecting method of the present invention can accurately detect defects on the pipe and accurately determine the position of the defect and the degree of the defect.

1 is a schematic flow chart showing a pipe defect detecting method according to a first embodiment of the present invention. As shown in FIG. 1, a pipe defect detecting method according to a first embodiment of the present invention includes: S1, detecting a first parameter related to a magnetic induction intensity along a length direction of the pipe; S2, determining whether the first parameter exceeds a predetermined threshold; S3, determining a position at which the first parameter exceeds a predetermined threshold as a defect position of the pipe; and S4, determining a defect degree of the pipe based on a value of the first parameter exceeding a predetermined threshold.

Here, those skilled in the art can understand that when the first parameter is detected in the length direction of the pipe, the first parameter can be continuously detected at each point in the longitudinal direction of the pipe, or can be selectively in the length direction of the pipe. The plurality of points discretely detect the first parameter. That is, by detecting at one or several points on the pipe, it can be determined whether or not there is a defect at the detected position.

Specifically, the pipe defect detecting method according to the first embodiment of the present invention may include the steps of: detecting a first parameter related to the magnetic induction intensity at a first point on the pipe; determining whether the first parameter exceeds a predetermined threshold; The first parameter is determined to exceed a predetermined threshold, the first point is determined as a defect location on the pipeline, and the degree of defect at the first point is determined based on a value of the first parameter that exceeds a predetermined threshold.

However, those skilled in the art will appreciate that in order to ensure the accuracy and comprehensiveness of the detection, embodiments of the present invention preferably employ a continuous detection method. Moreover, those skilled in the art will appreciate that the following description can be equally applied to continuous detection and discrete detection of pipeline defects, and the embodiments of the present invention are not intended to be any limitation.

In the pipe defect detecting method according to the first embodiment of the present invention, the first parameter is a rate of change of a component of the magnetic induction in a first direction in a three-dimensional coordinate system in a second direction. Preferably, the first parameter is a rate of change of a component of the magnetic induction in a first reference direction in a three-dimensional coordinate system in a second reference direction. Also, in the three-dimensional coordinate system, the first direction may be the same as the second direction or may be different from the second direction.

Here, the reference direction in the three-dimensional coordinate system refers to the x direction, the y direction, or the z direction in the three-dimensional coordinate system, and the first reference direction may be the same as the second reference direction or may be different from the second reference direction. For example, the first parameter may be a rate of change of the component H _x of the magnetic induction in the x direction in the three-dimensional coordinate system in the y direction, ie,

Abbreviated as g _xy . In this case, the first parameter is usually referred to as a magnetic field gradient, so g _xy is also referred to as the magnetic field gradient of the component of the magnetic induction in the x direction in the y direction. However, those skilled in the art can understand that the first parameter may also be a rate of change of the component of the magnetic induction in a certain direction in the other coordinate system along the direction or the other direction. Also, even in a three-dimensional coordinate system having x, y, and z directions, the first reference direction and the second reference direction are not limited to the x, y, or z directions, and may be, for example, an xy direction, a yz direction, or the like. Also, the first direction may be the same direction as the second direction, or may be a different direction. For example, correspondingly, the first parameter may also be a rate of change of the component H _x of the magnetic induction in the x direction in the three-dimensional coordinate system in the x direction, ie,

Abbreviated as g _xx . Therefore, the first parameter relating to the magnetic induction strength is not intended to be any limitation as long as it can reflect the defect position and the degree of defect of the pipe.

In the pipe defect detecting method according to the first embodiment of the present invention, after detecting the first parameter related to the magnetic induction intensity along the length direction of the pipe, the amplitude value of the first parameter can be plotted relative to the length direction of the pipe. The distance of the graph. Specifically, taking the detected end of the pipe as the origin, taking the distance of the detected point from the origin as the x coordinate, and plotting the amplitude of the first parameter as the y coordinate, plot the curve in the xy coordinate system, for example, as shown in picture 2. In this way, by observing the graph, the defect position and defect degree of the pipeline can be visually judged, so that the result display is more intuitive.

In the pipe defect detecting method according to the first embodiment of the present invention, determining the degree of defect of the pipe based on the value of the first parameter exceeding a predetermined threshold value specifically includes determining a defect of the pipe based on an amplitude of the first parameter exceeding a predetermined threshold Size; and/or determining the defect length of the conduit based on the length of the first parameter continuously exceeding a predetermined threshold.

As shown in FIG. 2, while determining that there is a defect in the pipeline, the specific condition of the pipeline defect can also be determined based on the value of the first parameter. For example, the magnitude of the first parameter exceeding a predetermined threshold may reflect the defect size of the pipe, ie, the greater the magnitude of the first parameter exceeding the predetermined threshold, indicating that the defect of the pipe is greater. Moreover, the length of the first parameter continuously exceeding the predetermined threshold may reflect the length of the defect of the pipe, that is, the longer the length of the first parameter continuously exceeding the predetermined threshold, indicating that the defect of the pipe is longer. In addition, based on the specific nature of the first parameter and the different data processing methods, other cases of pipeline defects may also be reflected, which are not enumerated herein.

In the pipe defect detecting method according to the first embodiment of the present invention, the method further includes: detecting a second parameter related to the magnetic induction intensity along a length direction of the pipe; determining whether the second parameter exceeds a predetermined threshold; The position where the second parameter exceeds the predetermined threshold is determined as the defect position of the pipe; The degree of defect of the pipe is determined by the value of the second parameter exceeding a predetermined threshold.

Here, in order to further improve the detection accuracy of defects in the pipe, the pipe defect detecting method according to the first embodiment of the present invention may detect the first parameter related to the magnetic induction intensity along the length direction of the pipe while along the pipe The length direction detects a second parameter related to the magnetic induction. And, preferably, the second parameter is a parameter related to the first parameter, that is, the second parameter may be a third-party component of the magnetic induction in a three-dimensional coordinate system in a fourth direction. Rate of change. For example, the third direction and the fourth direction are also reference directions in a three-dimensional coordinate system, and the second parameter is a rate of change of the component H _y of the magnetic induction in the y direction in the three-dimensional coordinate system in the z direction, that is, ,

Abbreviated as g _yz . Similarly, the third direction may be the same direction as the fourth direction, or a different direction. In this way, it will help to assist the first parameter to further determine the location of the defect and the extent of the defect on the pipe. Certainly, those skilled in the art can understand that, like the first parameter, the second parameter in the pipeline defect detecting method according to the first embodiment of the present invention is not limited to the third-party component of the magnetic induction intensity in the three-dimensional coordinate system. The rate of change in the fourth direction, but as long as the second parameter reflects the defect in the detected pipe. Moreover, the second parameter does not need to be related to the first parameter, so that the defect of the pipeline can be detected from multiple angles, and the detection of a certain parameter is invalid due to some special circumstances.

In the process of assisting the first parameter to further determine the defect position and the defect degree on the pipeline, when the position where the first parameter exceeds the predetermined threshold is the same position as the position where the second parameter exceeds the predetermined threshold, then determining The position is a position where the defect exists on the pipe, and when the position where the first parameter exceeds the predetermined threshold is different from the position where the second parameter exceeds the predetermined threshold, the position and the position where the first parameter exceeds the predetermined threshold The position where the second parameter exceeds the predetermined threshold is determined as the position where the defect exists on the pipe. And, when the position where the first parameter exceeds the predetermined threshold and the position where the second parameter exceeds the predetermined threshold are different positions, the pipeline may be determined based on the value of the first parameter and the value of the second parameter, respectively. Defect situation. Preferably, when the position where the first parameter exceeds the predetermined threshold is the same position as the position where the second parameter exceeds the predetermined threshold, the value of the first parameter exceeding the predetermined threshold and the number exceeding the predetermined threshold The larger of the two parameter values determines the degree of defect in the pipe. Specifically, determining a defect size of the pipeline based on a larger one of an amplitude of the first parameter exceeding a predetermined threshold and an amplitude of the second parameter exceeding a predetermined threshold, and based on the first parameter exceeding a predetermined threshold The larger of the length and the length of the second parameter exceeding the predetermined threshold determines the defect length of the conduit. Of course, according to the specific properties of the first parameter and the second parameter, such as the first parameter and the second parameter The actual selection of the number, and the correlation between the first parameter and the second parameter, etc., may also be when the position where the first parameter exceeds a predetermined threshold is the same position as the position where the second parameter exceeds a predetermined threshold Other ways to determine the degree of defect of the pipe at the location based on the value of the first parameter and the value of the second parameter, for example, in the form of a weighted sum of the value of the first parameter and the value of the second parameter. Those skilled in the art will appreciate that the embodiments of the present invention are not intended to be limited in any way.

Moreover, those skilled in the art can understand that the pipe defect detecting method according to the first embodiment of the present invention can further detect another one related to the magnetic induction intensity along the length direction of the pipe, in addition to the first parameter and the second parameter. Or multiple parameters. For example, by taking the rate of change of the component of the magnetic induction in a certain reference direction in the three-dimensional coordinate system in another reference direction, it is possible to detect three components of the three reference directions of the magnetic induction in the three-dimensional coordinate system ( The rate of change of H _x , H _y , H _z ) in the three directions (x, y, z) of the coordinate system, respectively. In this way, a magnetic gradient matrix comprising a total of nine elements can be constructed, denoted as G, which is expressed as follows:

Moreover, in the passive space, the divergence and the curl of the magnetic induction are 0, that is,

Thus, among the nine elements in the magnetic gradient matrix, only the values of five mutually independent elements are needed to calculate the values of all the elements in the matrix; of course, in practical applications, the operator can select six The value of 7, 9 or even all 9 elements is detected, but in fact only 5 values need to be measured and other values can be obtained after calculation, thereby obtaining the above magnetic gradient matrix.

When detecting one or more parameters related to magnetic induction, as described above, the defect map can be drawn, making the condition of the pipeline defect more intuitive. 2 is a schematic diagram of a graph drawn by detecting five elements of a magnetic gradient matrix. As shown in FIG. 2, by detecting the values of five independent elements of the nine elements in the magnetic field gradient matrix, and plotting the values of the five elements with respect to the distance in the x-y coordinate system The curve gives the five curves as shown.

In the pipe defect detecting method according to the first embodiment of the present invention, the predetermined threshold value may be selected empirically by a person skilled in the art, or may be set to a fixed value, for example, an average value of the first parameter over the length of the entire pipe, etc. And so on, as long as the defect and the degree of defect can be relatively accurately determined by comparing the first parameter with the predetermined threshold.

Preferably, in the pipe defect detecting method according to the first embodiment of the present invention, in order to make the comparison of the first parameter with the predetermined threshold value accurately reflect whether or not there is a defect, and the numerical value of the first parameter can accurately reflect the defect To the extent, the first parameter is processed as follows and a predetermined threshold is set. Specifically, determining whether the first parameter exceeds a predetermined threshold comprises: performing differential processing on the first parameter; adding, subtracting, and subtracting a variance of a magnitude of a first parameter after the differential processing as a predetermined threshold, where 1≤ n ≤ 3; and determining whether the first parameter exceeds a predetermined threshold.

The following is an example of differential processing of magnetic induction intensity. When performing differential processing, the magnetic induction intensity of adjacent points is derived, as shown in the following formula 3:

Where: E(x) represents the magnetic induction at the x position, and E(x+Δx) represents the magnetic induction at the x+Δx position. In this way, the result E'(x) after the differential processing can be obtained, which can indicate the magnitude of the change in the magnetic field at the front and rear positions, and can be used to determine whether the defect exists and where it is located.

Here, in determining whether a defect exists, the variance of the magnetic induction intensity change can be obtained for the detected magnetic induction intensity according to the principle of mathematical statistics, as shown in the following formula 4:

among them,

Moreover, according to the principle of mathematical statistics, when E'(x)>|nD(x)|, it can be determined as a defect, and the value of n is determined according to the size of the defect to be detected, generally 1≤n≤3.

Of course, those skilled in the art can understand that the above description has been made by taking the magnetic induction intensity as an example. When the first parameter is other parameters related to the magnetic induction, the differential processing can also be performed in a similar manner and the corresponding threshold is determined. Therefore, in order not to obscure the essential features of this application, it will not be carried out here. Said.

FIG. 3 is a schematic diagram of a curve obtained by performing differential processing on one of the curves in FIG. 2. FIG. As shown in FIG. 3, after the differential processing of one of the graphs in FIG. 2, the upper and lower defect threshold lines indicating the predetermined threshold are further set in the graph of FIG. In FIG. 3, the variance of the amplitude of the first parameter after the differential processing is added and subtracted by a factor of three, and is set as the upper and lower defect threshold lines. Thus, it can be visually seen from FIG. 3 that the first parameter after the differential processing exceeds a predetermined threshold.

By intercepting the portion of the first parameter after the differential processing in FIG. 3 that exceeds the predetermined threshold, it is possible to intuitively indicate that the first parameter relating to the magnetic induction intensity has an abnormal abnormal region over the entire length of the pipe. Fig. 4 is a schematic view showing an abnormal region shown after the five curves shown in Fig. 2 are processed. As shown in FIG. 4, three of the curves are processed to indicate an abnormality, and the two curves do not indicate an abnormality after being processed.

After that, the abnormal regions indicated by the plurality of curves can be integrated according to the above method. That is, the abnormal regions having the same position in the x-axis direction are combined and the maximum value thereof is taken, and the abnormal regions having different positions in the x-axis direction are retained. Thus, the abnormal regions indicated by the five curves shown in Fig. 4 are integrated into one image, thereby clearly showing the defect position and the degree of defects on the pipe, as shown in Fig. 5. Fig. 5 is a schematic view showing the integration of the abnormal regions shown after the processing shown in Fig. 4.

In the pipe defect detecting method according to the first embodiment of the present invention, determining whether the first parameter exceeds a predetermined threshold further comprises: detecting at each point along a length direction of the pipe in the case where there is no pipe to be detected a third parameter related to the magnetic induction intensity, wherein the third parameter is the same parameter as the first parameter; and, in a case where the first parameter is greater than the third parameter, the first parameter is the third parameter Optimization is performed and it is determined whether the optimized first parameter exceeds a predetermined threshold.

In reality, even in the absence of a pipeline to be inspected, there may be a background field having a certain magnetic induction intensity in the space to be detected, so that the first parameter related to the magnetic induction intensity cannot accurately represent the pipeline. abnormal. Therefore, preferably, when it is determined whether the first parameter exceeds a predetermined threshold, the first parameter can be optimized by the data obtained by detecting the background field, thereby enabling the first parameter to more accurately represent the abnormality of the pipe. For example, the first parameter is the rate of change of the component H _x in the y direction of the magnetic induction in the three-dimensional coordinate system, that is, g _xy . In the case where the pipe to be inspected is not present, the component H _x in the x direction in the three-dimensional coordinate system at the respective points can be measured in the y direction in the same manner along the length direction of the pipe. The rate of change is recorded as g' _xy . Then, the value of g _xy -g' _xy is taken as the optimized g _xy and it is determined whether it exceeds a predetermined threshold. Certainly, those skilled in the art can understand that the first parameter can be optimized by using the third parameter in other manners. For example, whether the amplitude of the first parameter is greater than the maximum amplitude of the third parameter can be determined, thereby determining the detected Whether a parameter is greater than the data of the background field, and the first parameter of the data larger than the background field is used as a reference for judging whether it is a pipe defect. In addition, the step of optimizing the first parameter with the data of the background field may be performed before the data of the first parameter is processed and compared with a predetermined threshold, or after the data of the first parameter is processed and compared with a predetermined threshold. However, if the first parameter is optimized with the data of the background field after the data of the first parameter is processed and compared with the predetermined threshold, the data of the background field should also be processed corresponding to the first parameter and compared with a predetermined threshold. . For example, the third parameter of the background field is differentially processed and the upper and lower defect threshold lines are set. In this case, the abnormal area caused by the background place may be directly removed from the abnormal area indicated by the first parameter, or the abnormal area indicated by the first parameter may be optimized by the abnormal area caused by the background place.

In the pipe defect detecting method according to the first embodiment of the present invention, after the abnormal region indicating the magnetic abnormality is optimized according to the background field, the abnormal characteristics of each magnetic abnormal region may be included, including the magnetic abnormality start and end positions. And the magnetic anomaly amplitude to specifically determine the defect position, the defect length and the defect size in the pipeline, thereby obtaining the final defect display result. By determining the position of the defect in the abscissa, determining the length of the defect by the length of the abscissa of the magnetic anomaly zone, and determining the size of the defect by the ordinate, the defect diagram of the pipe can be further fabricated, for example, as shown in FIG. . Fig. 6 is a schematic view of a pipe defect produced based on the integrated abnormal region shown in Fig. 5. In this way, the defects of the pipeline can be more intuitively understood than the graph, so that the maintenance of the pipeline can be repaired and maintained for the pipeline defects, which reduces the cost and facilitates the convenience.

Thus, with the pipe defect detecting method according to the first embodiment of the present invention, the defect position on the pipe can be accurately detected, and the degree of defect can be accurately determined, thereby saving the cost of pipe inspection and maintenance and facilitating the user's convenience. .

A second embodiment of the present invention provides a pipeline defect detecting apparatus, comprising: a detecting unit configured to detect a first parameter related to a magnetic induction intensity along a length direction of the pipeline; and a determining unit configured to determine the first parameter Whether a predetermined threshold is exceeded; and a control unit configured to determine a position at which the first parameter exceeds a predetermined threshold as a defect position of the pipe, and determine a degree of defect of the pipe based on a value of the first parameter exceeding a predetermined threshold.

Fig. 7 is a schematic block diagram illustrating a pipe defect detecting device according to a second embodiment of the present invention. As shown in FIG. 7, a pipe defect detecting apparatus 100 according to a second embodiment of the present invention includes: a detecting unit 101 configured to detect a first parameter related to a magnetic induction intensity along a length direction of the pipe; and a determining unit 102 configured to Determining whether the first parameter exceeds a predetermined threshold based on the first parameter detected by the detecting unit 101; and the control unit 103 is configured to determine, based on the result of the determining unit 102 whether the first parameter exceeds a predetermined threshold, The position at which the first parameter exceeds the predetermined threshold is determined as the defect position of the pipe, and the degree of defect of the pipe is determined based on the value of the first parameter exceeding a predetermined threshold.

In the above-described pipe defect detecting device, the second parameter is a rate of change of the component of the third-order direction of the magnetic induction in the three-dimensional coordinate system in the fourth direction.

As described above, in the pipe defect detecting method according to the first embodiment of the present invention, and the pipe defect detecting device according to the second embodiment of the present invention, the component of the magnetic induction intensity in a certain reference direction in the three-dimensional coordinate system can be used. The rate of change in the other reference direction serves as a first parameter related to the magnetic induction, and in this case the first parameter is generally referred to as a magnetic field gradient, and the parameter is detected using a corresponding magnetic field gradient detecting device. Figure 8 is a schematic illustration of a magnetic field gradient detecting component in accordance with an embodiment of the present invention. As shown in Fig. 8, a magnetic field gradient detecting section 200 according to an embodiment of the present invention includes four three-component magnetic detecting sensors B ₀ , B ₁ , B ₂ and B ₃ arranged in a cross on one plane, and four of them are detected. The magnetic induction values of the three directions in each of the three-component magnetic sensors are used to calculate the magnetic field gradient at the center of the cross, thereby measuring the magnetic gradient matrix of the center of the cross. Of course, those skilled in the art can understand that the magnetic field gradient value measured by the magnetic field gradient detecting component 200 shown in FIG. 8 is more accurate, but in the pipeline defect detecting method and the pipeline defect detecting device according to the embodiment of the present invention, Other types of magnetic field gradient detecting components can be used for detection.

As shown in FIG. 8, the magnetic field gradient measuring device 100 using the four magnetic detecting sensors B ₀ , B ₁ , B ₂ and B ₃ arranged in a cross shape can detect the magnetic field gradient, wherein the magnetic measuring sensors B ₀ , B ₁ , Each of B ₂ and B ₃ is a three-component magnetic measuring sensor, that is, capable of measuring magnetic induction components in the x, y, and z directions. As shown in Fig. 8, in one plane, B ₀ and B _{2 are} symmetrically arranged, B ₁ and B _{3 are} symmetrically arranged, and the distance from B ₀ to the center, the distance from B ₂ to the center, the distance from B ₁ to the center, and B The distance from ₃ to the center is the same. Of course, those skilled in the art can understand that in practical applications, as long as B ₀ and B _{2 are} symmetrically arranged, B ₁ and B ₃ can be symmetrically set, and the distance between B ₀ and B ₂ can also be compared with B ₁ to B _{3 .} The distance between them is different, and the same is set only to facilitate the calculation of the magnetic field gradient. Then, by the magnetic field gradient measuring device 100, the magnetic field gradient matrix of the center point is obtained as follows:

Δx in the above formula 3 is the distance between the B ₁ sensor and the B ₃ sensor, Δz is the distance between the B ₀ sensor and the B ₂ sensor, and B _1x is the magnetic induction component of the x direction measured by the B ₁ sensor. B _3x is the magnetic induction component of the x direction measured by the B ₃ sensor, B _1y is the magnetic induction component of the y direction measured by the B ₁ sensor, and B _3y is the magnetic induction component of the y direction measured by the B ₃ sensor, in turn analogy. The values of the nine elements of the magnetic field gradient matrix G can be obtained by measurement, but as in the above, in practical applications, since the formula 2 is also satisfied, it is only necessary to obtain the values of five elements to extract all nine elements. Value. Further, from the above formula 3, a value of any component H _x , H _y or H _{z of the} magnetic induction in three reference directions in the three-dimensional coordinate system in any reference direction can be obtained, for example, g _xy = (B _1x -B _3x ) / Δx. Therefore, the values of the required elements can be calculated as needed.

Moreover, those skilled in the art can understand that when the first parameter related to the magnetic induction intensity is not the magnetic field gradient, for example, the attenuation amount of the magnetic induction intensity, different devices can be used for detection, and the embodiment of the present invention is not intended to Make any restrictions.

A third embodiment of the present invention provides a pipe defect detecting apparatus comprising: a shelf placed above a pipe to be inspected; a sliding track disposed on the shelf and slidable along a length of the shelf; The pipe defect detecting device is slidably connected to the sliding track by a slider to detect a pipe defect of the pipe to be detected.

Fig. 9 is a schematic view showing a pipe defect detecting apparatus according to a third embodiment of the present invention. As shown in FIG. 9, the pipe defect detecting apparatus 10 includes a rack 1, a slide rail 2, and a duct defect detecting device 3. The pipe defect detecting device 3 is placed above the pipe by providing a rack 1, and the frame 1 is provided with a slide rail 2. The pipe defect detecting device 3 is slidably coupled to the slide rail 2 by a slider. At the time of detection, the shelf 1 is left stationary, and the pipe defect detecting device 3 slides at a uniform speed on the slide rail 2 to perform detection. The pipeline defect detecting device 3 can be uniformly slid on the sliding rail 2 by the actuating device, and the actuating device can control the moving of the object uniformly on the sliding rail by using human, air pressure, hydraulic pressure or the like. In the case where the length of the shelf is smaller than the length of the pipe to be inspected, after the detection of the position at which the shelf 1 is completed, the position of the shelf 1 is moved to start the next detection. In this way, the pipeline defect detecting device can minimize the problem of the moving track sway or the moving speed caused by the artificially controlled movement, so that the external interference is minimized and the detection result is more accurate.

According to the pipe defect detecting method, the pipe defect detecting device and the pipe defect detecting device of the present invention, it is possible to determine whether the pipe has a defect based on a parameter related to the magnetic induction strength, and to determine the defect position of the pipe according to the abnormal position of the parameter, and Determine the tube based on the value of the parameter with the abnormality The extent of the defect. In this way, the position of defects and the degree of defects on the pipe can be accurately detected.

The invention may, of course, be embodied in a variety of other embodiments and various modifications and changes can be made in accordance with the present invention without departing from the spirit and scope of the invention. Corresponding changes and modifications are intended to be included within the scope of the appended claims.

Claims

A method for detecting pipeline defects, comprising:

Detecting a first parameter related to magnetic induction along a length direction of the pipe;

Determining whether the first parameter exceeds a predetermined threshold;

Determining the position where the first parameter exceeds a predetermined threshold as a defect position of the pipe; and

The degree of defect of the pipe is determined based on the value of the first parameter exceeding a predetermined threshold.
The pipe defect detecting method according to claim 1, wherein the first parameter is a rate of change of a component of the magnetic induction in a first direction in a three-dimensional coordinate system in a second direction.
The pipe defect detecting method according to claim 2, wherein the first direction is the same as the second direction, or the first direction is different from the second direction.
The pipe defect detecting method according to claim 1, wherein determining the degree of defect of the pipe based on the value of the first parameter exceeding a predetermined threshold specifically comprises:

Determining a defect size of the conduit based on the magnitude of the first parameter exceeding a predetermined threshold; and/or

The defect length of the pipe is determined based on the length of the first parameter continuously exceeding a predetermined threshold.
The pipeline defect detecting method according to claim 1, further comprising:

A plot of the amplitude value of the first parameter versus the distance in the length direction of the conduit is plotted.
The pipeline defect detecting method according to claim 1, further comprising:

Detecting a second parameter related to the magnetic induction along the length of the pipe;

Determining whether the second parameter exceeds a predetermined threshold; determining a position at which the second parameter exceeds a predetermined threshold as a defect location of the pipeline; and

The degree of defect of the pipe is determined based on the value of the second parameter exceeding a predetermined threshold.
The pipe defect detecting method according to claim 6, wherein when the position where the first parameter exceeds a predetermined threshold and the position where the second parameter exceeds a predetermined threshold are the same position, the first is based on exceeding a predetermined threshold The value of the parameter and the value of the second parameter exceeding a predetermined threshold determine the degree of defect in the pipe.
The pipe defect detecting method according to claim 7, wherein the second parameter is a rate of change of a component of the magnetic induction in a third direction in a three-dimensional coordinate system in a fourth direction.
The pipeline defect detecting method according to claim 8, wherein said third direction and fourth party The same, or the third direction is different from the fourth direction.
The pipe defect detecting method according to claim 9, wherein the first direction, the second direction, the third direction, and the fourth direction are one of an x direction, a y direction, and a z direction in a three-dimensional coordinate system.
The method for detecting a pipeline defect according to claim 1, wherein the method for determining whether the first parameter exceeds a predetermined threshold comprises:

Performing differential processing on the first parameter;

The variance of the amplitude mean value of the first parameter after the differential processing is added or subtracted by n times as a predetermined threshold, wherein 1≤n≤3;

Determining whether the first parameter exceeds a predetermined threshold.
The pipeline defect detecting method according to claim 1, wherein determining whether the first parameter exceeds a predetermined threshold further comprises:

In the absence of the pipeline to be inspected, a third parameter related to the magnetic induction is detected along the length direction of the pipeline, wherein the third parameter is the same parameter as the first parameter;

In case the first parameter is greater than the third parameter, the first parameter is optimized with a third parameter, and it is determined whether the optimized first parameter exceeds a predetermined threshold.
The pipe defect detecting method according to claim 10, further comprising: in addition to the first parameter and the second parameter related to the magnetic induction, further detecting three references of the magnetic induction in the three-dimensional coordinate system along the length direction of the pipe The three components H x , H y , H z in the direction are respectively changed in the three directions x, y, z of the coordinate system to form a magnetic gradient matrix G comprising a total of 9 elements:
A pipeline defect detecting device includes:

a detecting unit configured to detect a first parameter related to the magnetic induction intensity along a length direction of the pipe;

a determining unit, configured to determine whether the first parameter exceeds a predetermined threshold; and

And a control unit configured to determine a position at which the first parameter exceeds a predetermined threshold as a defect position of the pipe, and determine a degree of defect of the pipe based on a value of the first parameter exceeding a predetermined threshold.
The pipe defect detecting device according to claim 14, wherein said first parameter is said The rate of change of the component of the magnetic induction in the first direction in the three-dimensional coordinate system in the second direction.
The pipe defect detecting device according to claim 15, wherein the first direction is the same as the second direction, or the first direction is different from the second direction.
The pipe defect detecting device according to claim 14, wherein the control unit further comprises:

a defect size determining module configured to determine a defect size of the pipeline based on an amplitude of the first parameter exceeding a predetermined threshold; and/or

A defect length determination module configured to determine a defect length of the pipe based on a length of the first parameter continuously exceeding a predetermined threshold.
The pipe defect detecting apparatus according to claim 14, further comprising:

a drawing unit configured to plot a magnitude of the amplitude value of the first parameter relative to a distance in a length direction of the pipe based on the first parameter detected by the detecting unit.
The pipe defect detecting device according to claim 14, wherein

The detecting unit is further configured to detect a second parameter related to the magnetic induction intensity along a length direction of the pipe;

Determining that the power source is further configured to determine whether the second parameter exceeds a predetermined threshold; and

The control unit is further configured to determine a position at which the second parameter exceeds a predetermined threshold as a defect position of the pipe, and determine a degree of defect of the pipe based on a value of the second parameter exceeding a predetermined threshold.
The pipe defect detecting apparatus according to claim 19, wherein said control unit is based on exceeding a predetermined threshold when determining that said first parameter exceeds a predetermined threshold and said second parameter exceeds a predetermined threshold The value of the first parameter and the value of the second parameter exceeding a predetermined threshold determine the degree of defect in the pipe.
The pipe defect detecting device according to claim 19, wherein said second parameter is a rate of change of a component of said magnetic induction in a third direction in a three-dimensional coordinate system in a fourth direction.
The pipe defect detecting device according to claim 21, wherein the third direction is the same as the fourth direction, or the third direction is different from the fourth direction.
The duct defect detecting apparatus according to claim 22, wherein the first direction, the second direction, the third direction, and the fourth direction are one of an x direction, a y direction, and a z direction in the three-dimensional coordinate system.
The pipe defect detecting device according to claim 14, wherein the determining unit further comprises:

a differential processing module configured to perform differential processing on the first parameter;

An arithmetic processing module configured to: add, subtract, or subtract a variance of the amplitude mean of the first parameter after the differential processing of the differential processing module by a variance by a predetermined threshold, wherein 1≤n≤3;

The determining module is configured to determine whether the first parameter exceeds a predetermined threshold.
The pipe defect detecting device according to claim 14, wherein

The detecting unit is further configured to detect a third parameter related to the magnetic induction intensity along a length direction of the pipeline in the absence of the pipeline to be detected, wherein the third parameter is the same parameter as the first parameter;

The determining unit is further configured to optimize the first parameter with a third parameter if the first parameter is greater than the third parameter, and determine whether the optimized first parameter exceeds a predetermined threshold.
The pipe defect detecting apparatus according to claim 22, wherein said detecting unit is further configured to detect the magnetic induction in the three-dimensional coordinate system along the length direction of the pipe in addition to the first parameter and the second parameter related to the magnetic induction The three components H x , H y , H z in the three reference directions are in the three directions x, y, z of the coordinate system, respectively, to form a magnetic gradient matrix G comprising a total of nine elements:
A pipe defect detecting apparatus according to claim 26, wherein said detecting unit specifically comprises a first three-component magnetic detecting sensor, and a second symmetrically arranged with said first three-component magnetic detecting sensor at a center of said detecting unit a three-component magnetic sensor, a third three-component magnetic sensor, and a fourth three-component magnetic sensor symmetrically arranged with the third three-component magnetic sensor at the center of the detecting unit,

Wherein the first, second, third and fourth three-component magnetic sensors are arranged in a cross on one plane; each of the first, second, third and fourth three-component magnetic sensors The magnetic sensor calculates the magnetic field ladder at the center of the cross by detecting the value of the magnetic induction in three reference directions of the three-dimensional coordinate system. Degree, thus measuring the magnetic field gradient matrix G of the center of the cross:

Where Δx is the distance between the first three-component magnetic sensor and the second three-component magnetic sensor, and Δz is between the third three-component magnetic sensor and the fourth three-component magnetic sensor. Distance, B 1x is the magnetic induction component of the x direction measured by the first three-component magnetic sensor, and B 1y is the magnetic induction component of the y direction measured by the first three-component magnetic sensor, and B 1z is the first three The magnetic induction component of the z direction measured by the component magnetic sensor, B 2x is the magnetic induction component of the x direction measured by the second three component magnetic sensor, and B 2y is measured by the second three component magnetic sensor The magnetic induction component of the y direction, B 2z is the magnetic induction component of the z direction measured by the second three component magnetic sensor, and B 0x is the magnetic induction component of the x direction measured by the third three component magnetic sensor, B 0y is the magnetic induction component of the y direction measured by the third three-component magnetic sensor, B 0z is the magnetic induction component of the z direction measured by the third three component magnetic sensor, and B 2x is the fourth three component measurement. component of the magnetic induction measured in the x-direction magnetic sensors, B 2y fourth Y-direction component of the magnetic induction of the magnetic sensor sensing component measured magnetic flux density component 2z z direction is a fourth three-component magnetic measurement measured by the sensor B.
A pipeline defect detecting device includes:

a shelf placed above the pipe to be tested;

a sliding track that is placed on the shelf and slidable along the length of the shelf; and

The pipe defect detecting device as described above is slidably coupled to the sliding rail by a slider to detect a pipe defect of the pipe to be detected.
A pipe defect detecting apparatus according to claim 28, further comprising an actuating means for causing said pipe defect to slide at a uniform speed on said sliding track.
A pipe defect detecting apparatus according to claim 29, wherein said actuating means employs an actuating mode including any one of manpower, air pressure, and hydraulic pressure.
A method for detecting pipeline defects, comprising:

Measuring a first parameter related to the magnetic induction intensity at a first point on the pipeline;

Determining whether the first parameter exceeds a predetermined threshold;

If the first parameter exceeds a predetermined threshold, the first point is determined to be a defect location of the pipeline, and a defect level of the first point is determined based on a value of the first parameter that exceeds a predetermined threshold.
The pipe defect detecting method according to claim 31, wherein said first parameter is a rate of change of a component of said magnetic induction in a first direction in a three-dimensional coordinate system in a second direction.
The pipe defect detecting method according to claim 32, wherein the first direction is the same as the second direction, or the first direction is different from the second direction.
The pipeline defect detecting method according to claim 31, further comprising:

Measuring a second parameter related to the magnetic induction intensity at a first point on the pipeline;

Determining whether the second parameter exceeds a predetermined threshold;

If the second parameter exceeds a predetermined threshold, the defect level of the pipe is determined based on the value of the first parameter exceeding a predetermined threshold and the value of the second parameter exceeding a predetermined threshold.
The pipe defect detecting method according to claim 34, wherein said second parameter is a rate of change of a component of said magnetic induction in a third direction in a three-dimensional coordinate system in a fourth direction.
The pipe defect detecting method according to claim 35, wherein the third direction is the same as the fourth direction, or the third direction is different from the fourth direction.
The pipe defect detecting method according to claim 36, wherein the first direction, the second direction, the third direction, and the fourth direction are one of an x direction, a y direction, and a z direction in the three-dimensional coordinate system.
The method for detecting a pipeline defect according to claim 31, wherein the method for determining whether the first parameter exceeds a predetermined threshold comprises:

Performing differential processing on the first parameter;

The variance of the amplitude mean of the first parameter after the differential processing is added or subtracted by n times as a predetermined threshold. Where 1 ≤ n ≤ 3;

Determining whether the first parameter exceeds a predetermined threshold.
The pipeline defect detecting method according to claim 31, wherein determining whether the first parameter exceeds a predetermined threshold further comprises:

And detecting, in the absence of the pipeline to be detected, a third parameter related to the magnetic induction intensity at the first point, wherein the third parameter is the same parameter as the first parameter; and

In case the first parameter is greater than the third parameter, the first parameter is optimized with a third parameter, and it is determined whether the optimized first parameter exceeds a predetermined threshold.
A pipe defect detecting method according to claim 37, further comprising: in addition to the first parameter and the second parameter related to the magnetic induction, further detecting three references of the magnetic induction in the three-dimensional coordinate system at the first point The three components H x , H y , H z in the direction are respectively changed in the three directions x, y, z of the coordinate system to form a magnetic gradient matrix G comprising a total of 9 elements: