A ferrofluid in-pipe inspection device, system and method for detecting defects in a pipe

Abstract

This invention discloses an internal inspection device, system, and method for pipeline defects in ferromagnetic fluid pipelines, particularly relating to the field of defect detection. The method includes: a fixed assembly, multiple permanent magnet assemblies, and multiple arrayed ferromagnetic conductor detection assemblies. The permanent magnet assemblies are uniformly arranged circumferentially on the outer wall of the fixed assembly, with the south pole of each permanent magnet assembly facing the fixed assembly. The arrayed ferromagnetic conductor detection assemblies are installed at the north pole of each permanent magnet assembly. Each arrayed ferromagnetic conductor detection assembly includes multiple ferromagnetic fluid detection units, each ferromagnetic fluid detection unit comprising an upper electrode plate, a ferromagnetic fluid pore, and a lower electrode plate. The ferromagnetic fluid pore is positioned between the upper and lower electrode plates and is sealed and filled with ferromagnetic fluid. This invention can improve the accuracy of pipeline defect detection.

Description

Technical Field

[0001] This invention relates to the field of defect detection, and in particular to an internal inspection device, system and method for detecting defects in ferromagnetic fluid pipelines. Background Technology

[0002] As vital energy and material transport facilities, the safe operation of pipelines is of paramount importance. Currently, pipeline inspection technologies mainly include magnetic flux leakage detection and eddy current detection.

[0003] Among these technologies, magnetic flux leakage (MFL) detection is the most widely used. However, its detectors typically require a large magnetization structure and sensor array, resulting in bulky, heavy, and poorly maneuverable equipment, which limits its application, especially in small-diameter pipes or complex working conditions. In addition, traditional MFL detection has limited sensitivity in identifying minute defects. Summary of the Invention

[0004] This invention provides an internal inspection device, system, and method for detecting pipeline defects in ferromagnetic fluid pipelines, which can improve the accuracy of pipeline defect detection.

[0005] According to one aspect of the present invention, an internal inspection device for a ferromagnetic fluid pipeline is provided, characterized in that it comprises: a fixed component, a plurality of permanent magnet components, and a plurality of arrayed ferromagnetic conductor detection components. The permanent magnet components are uniformly arranged circumferentially on the outer wall of the fixed component, with the south pole of the permanent magnet components facing the fixed component. The arrayed ferromagnetic conductor detection components are installed at the north pole of the permanent magnet components. The arrayed ferromagnetic conductor detection components include a plurality of ferromagnetic fluid detection units. Each ferromagnetic fluid detection unit includes an upper electrode plate, a ferromagnetic fluid aperture, and a lower electrode plate. The ferromagnetic fluid aperture is located between the upper electrode plate and the lower electrode plate, and the ferromagnetic fluid aperture is sealed and filled with ferromagnetic fluid.

[0006] According to one aspect of the present invention, a ferromagnetic fluid pipeline internal inspection system is provided, comprising a ferromagnetic fluid pipeline internal inspection device and a processing unit as described in the embodiments of the present invention; the processing unit is connected to the upper electrode plate and the lower electrode plate in the ferromagnetic fluid pipeline internal inspection device.

[0007] According to one aspect of the present invention, a pipeline defect detection method is provided, applied to an internal inspection system for ferromagnetic fluid pipelines as described in the embodiments of the present invention, comprising: Obtain the reference voltage value obtained from the calibration of the ferromagnetic fluid pipeline internal inspection system; The voltage signal monitored in real time by the ferromagnetic fluid pipeline internal inspection system during its operation inside the pipeline to be inspected is acquired. The real-time voltage value is determined based on the real-time monitored voltage signal; The real-time voltage value is compared with the reference voltage value to obtain a voltage comparison result; Based on the voltage comparison results, the defect detection results of the pipeline to be inspected are determined.

[0008] The technical solution of this invention involves installing multiple permanent magnet components on a fixed section, and installing a ferrofluid detection array on each permanent magnet component. Each ferrofluid detection array contains multiple ferrofluid detection units, each of which can acquire signals to detect whether defects exist inside the pipeline. Utilizing ferrofluid as a sensitive medium simplifies the detection structure and replaces traditional magnetic leakage detection sections. Furthermore, each ferrofluid detection unit can highly sensitively sense and convert the magnetic field changes near the defect into measurable electrical signals, solving the technical problem of limited sensitivity in identifying minute defects in existing technologies. Based on the arrayed sensor structure, accurate identification and quantification of circumferential and axial defects in the pipeline can be achieved, improving the resolution and reliability of defect detection.

[0009] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of an internal inspection device for a ferromagnetic fluid pipeline according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a ferromagnetic conductor detection array according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the distance detection unit in an internal inspection system for ferromagnetic fluid pipelines according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a processing unit in an internal inspection system for ferromagnetic fluid pipelines according to an embodiment of the present invention; Figure 5 This is a flowchart of a pipeline defect detection method provided according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a processing unit provided according to an embodiment of the present invention. Detailed Implementation

[0012] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0013] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0014] Figure 1 This is a schematic diagram of a ferrofluid pipeline internal inspection device provided in an embodiment of the present invention. This embodiment of the invention is applicable to the internal inspection of pipeline defects, particularly suitable for online and in-service inspection of metal pipelines such as oil and gas pipelines and chemical pipelines, enabling precise identification and quantitative assessment of defects such as corrosion, cracks, and pits.

[0015] The ferromagnetic fluid pipeline internal inspection device includes: a fixed component 101, multiple permanent magnet components 102, and multiple ferromagnetic conductor detection arrays 103. Each permanent magnet component 102 is installed on the outer wall of the fixed component 101, with the south pole of the permanent magnet component 102 facing the fixed component 101. The ferromagnetic conductor detection array 103 is installed at the north pole of the corresponding permanent magnet component 102. The ferromagnetic conductor detection array 103 includes multiple ferromagnetic fluid detection units. Each ferromagnetic fluid detection unit includes an upper electrode plate, a ferromagnetic fluid pore, and a lower electrode plate. The ferromagnetic fluid pore is located between the upper electrode plate and the lower electrode plate, and the ferromagnetic fluid pore is sealed and filled with ferromagnetic fluid.

[0016] The fixing component 101 provides a mounting base for the permanent magnet component 102. Typically, the fixing component 101 can be a pipe with an outer diameter smaller than the inner diameter of the pipe to be tested. For example, the fixing component 101 is made of aluminum alloy with an outer diameter of 195 mm and a thickness of 40 mm.

[0017] The permanent magnet assembly 102 is mounted on the outer wall of the fixed assembly 101, and the permanent magnet assemblies 102 can be arranged as needed. The permanent magnet assemblies 102 are made of neodymium iron boron material to achieve high-intensity magnetic field excitation, and the magnetic poles of all permanent magnet assemblies 102 are aligned in the same direction. The permanent magnet assembly 102 can be an N52 grade neodymium iron boron permanent magnet (20mm × 20mm × 20mm). Here, N represents neodymium magnet, and 52 represents its maximum energy product ((BH)max) of 52 MGOe (mega-golo). The N pole of all permanent magnet assemblies 102 faces the inner wall of the pipe. The S pole of all permanent magnet assemblies 102 faces the outer wall of the fixed assembly 101.

[0018] The ferromagnetic conductor detection array 103 is located above the permanent magnet assembly 102. The fixing assembly 101 is located below the permanent magnet assembly 102. The ferromagnetic conductor detection array 103 and the fixing assembly 101 are located on different sides and at different poles of the permanent magnet assembly 102. The S (south) pole of the permanent magnet assembly 102 faces the fixing assembly 101, and the N (north) pole of the permanent magnet assembly 102 faces the ferromagnetic conductor detection array 103. The ferromagnetic conductor detection array 103 is mounted close to the N pole of the permanent magnet assembly 102.

[0019] The ferromagnetic conductor detection array 103 is an array formed by multiple ferromagnetic fluid detection units. For example... Figure 2 As shown, the ferromagnetic conductor detection array 103 includes ferromagnetic fluid detection units 201 arranged in an array. The ferromagnetic conductor detection array 103 has 16 ferromagnetic fluid detection units 201, which are 4 (circumferential) × 4 (axial). The number of ferromagnetic fluid detection units 201 can be determined according to the actual detection accuracy.

[0020] Meanwhile, the ferrofluid detection unit 201 includes an upper electrode plate 301, a ferrofluid pore 302, and a lower electrode plate 303. The ferrofluid pore 302 contains ferrofluid. Typically, the upper electrode plate 301 and the lower electrode plate 303 are gold-plated copper sheets. Ferrofluids possess superparamagnetic properties; when they encounter pipe defects, the magnetic field lines excited by the permanent magnet are distorted, resulting in a large number of magnetic field lines overflowing around the pipe defect. This alters the shape of the ferrofluid, thereby changing its conductivity. By accurately measuring this change in conductivity, high-precision non-destructive testing of defects can be achieved.

[0021] The technical solution of this invention involves installing multiple permanent magnet components on a fixed section, and installing a ferrofluid detection array on each permanent magnet component. Each ferrofluid detection array contains multiple ferrofluid detection units, each of which can acquire signals to detect whether defects exist inside the pipeline. Utilizing ferrofluid as a sensitive medium simplifies the detection structure and replaces traditional magnetic leakage detection sections. Furthermore, each ferrofluid detection unit can highly sensitively sense and convert the magnetic field changes near the defect into measurable electrical signals, solving the technical problem of limited sensitivity in identifying minute defects in existing technologies. Based on the arrayed sensor structure, accurate identification and quantification of circumferential and axial defects in the pipeline can be achieved, improving the resolution and reliability of defect detection.

[0022] Optional, such as Figure 3 The longitudinal section of the pipe shown shows that the ferromagnetic fluid pipe internal inspection device also includes: a distance detection unit 104, which is connected to the fixed component 101 and is used to determine the moving distance of the fixed component 101.

[0023] The distance detection unit 104 may include a mileage wheel and an elastic swing arm. The mileage wheel is movably connected to the fixed component 101 via the elastic swing arm, and the mileage wheel is always pressed against the inner wall of the pipe under the action of the spring of the elastic swing arm. When the fixed component 101 is pushed forward by the pipe medium, the mileage wheel rolls against the pipe wall, and the number of its rotations is converted into electrical pulse signals by a sensor. Since each rotation corresponds to a fixed wheel circumference, the moving distance of the fixed component 101 can be accurately calculated. In some embodiments, the structure from the inside to the outside is as follows: fixed component 101, elastic swing arm, mileage wheel, and inner wall of pipe 401.

[0024] To ensure ranging accuracy, 2-4 mileage wheels are typically evenly arranged around the circumference of the fixed component 101 and attached to the frame of the fixed component 101 or the sensor support ring. The spring-loaded clamping mechanism adapts to changes in pipe diameter and uneven pipe walls, ensuring the wheels always roll smoothly and preventing slippage, thus greatly improving the accuracy and reliability of long-distance pipeline defect location.

[0025] As can be seen, by measuring the movement distance of the fixed components using the mileage wheel, the actual mileage of the detection point can be accurately detected, fundamentally eliminating the gaps and elastic deformation errors caused by multi-body connections.

[0026] Optionally, the magnetic fluid pores 302 are filled with ferrofluid wrapped in a polymer film, and an upper electrode plate 301 or a lower electrode plate 303 is mounted on the surface of the high-resolution film.

[0027] The ferromagnetic fluid in the magnetic fluid pore 302 is encapsulated by a polymer film to prevent leakage. The ferromagnetic fluid is water-based. The polymer film can be a polyimide film. The magnetic fluid pore 302 (corresponding to a single ferromagnetic fluid detection unit 201) has a diameter of approximately 3 mm and a depth of 2 mm, is filled with water-based ferromagnetic fluid, and is sealed at the top and bottom by polyimide films.

[0028] It is evident that by reliably isolating the conductive ferrofluid from the electrodes using a polymer thin film, short circuits, electrochemical corrosion, and leakage can be avoided. At the same time, the deformation or permeability change of the ferrofluid under a magnetic field can cause a significant response in the capacitance or resistance between the electrodes, thereby converting magnetic field anomalies into electrical signals with high sensitivity. Furthermore, the thin-film encapsulation allows the sensor unit to be freely arranged within tiny pores and maintain long-term stability, making it ideal for dense and reliable array acquisition of signals such as leakage magnetic field in pipeline detectors.

[0029] Optionally, the spatial shape of the fixing component 101 is a hollow cylindrical structure, and each permanent magnet component 102 is evenly arranged along the circumference of the fixing component 101.

[0030] The hollow cylindrical structure allows the medium transported by the pipeline to pass through the middle of the fixing component 101, while the outer wall of the cylindrical fixing component 101 moves along the inside of the pipeline.

[0031] As can be seen, by adopting a hollow cylindrical structure for the fixed components, the medium transported in the pipeline can pass smoothly through the central flow channel, minimizing operating resistance and throttling effects, and ensuring that the internal detector can be smoothly propelled forward by the fluid without interrupting the flow. At the same time, arranging each permanent magnet component evenly along the circumference can establish a uniform, symmetrical, and closed magnetization field throughout the entire circumference of the pipe wall, achieving 360° saturation magnetization of the pipe body without dead angles. This ensures that defects in any direction can generate characteristic leakage magnetic signals, significantly improving the comprehensiveness of detection coverage, sensitivity, and positioning accuracy, and fundamentally avoiding missed detections or signal distortions caused by uneven magnetic field distribution.

[0032] Figure 4 This is a schematic diagram of the structure of a ferromagnetic fluid pipeline internal inspection system provided in an embodiment of the present invention. The ferromagnetic fluid pipeline internal inspection system includes a ferromagnetic fluid pipeline internal inspection device 100 and a processing unit 105 as described in any embodiment of the present invention; the processing unit 105 is connected to the upper electrode plate and the lower electrode plate in the ferromagnetic fluid pipeline internal inspection device 100.

[0033] The processing unit 101 can be integrated with the ferromagnetic fluid pipeline internal inspection device 100, and moves synchronously within the pipeline 401 along with the ferromagnetic fluid pipeline internal inspection device. The surface of the ferromagnetic fluid detection unit 201 is provided with miniature induction electrodes. The upper electrode plate 301 or the lower electrode plate 303 is connected to the processing unit via micro-wires.

[0034] The technical solution of this invention, by directly connecting the processing unit to the upper and lower electrode plates of the ferrofluid pipeline internal inspection device, enables the local acquisition and real-time transmission of electrode sensing signals, shortens the signal routing length, effectively reduces the interference of complex media inside the pipeline and external electromagnetic environment on weak detection signals, and reduces signal attenuation and noise interference. At the same time, it is easy to integrate the layout based on the hollow cylindrical structure of the ferrofluid pipeline internal inspection device, without the need for external wiring, with a compact structure and high integration. It can condition, convert analog to digital and store the ferrofluid sensing signals acquired by the electrodes in real time, ensuring the integrity, stability and detection accuracy of pipeline defect detection signals, and is suitable for the closed and confined working environment of pipelines with complex operating conditions.

[0035] Optionally, the processing unit 105 includes: an analog-to-digital conversion module, a signal conditioning module, and a storage module.

[0036] The processing unit 105 is capable of reading and recording the electrode voltages of the ferromagnetic conductor detection array 103, including the arrayed ferrofluid detection units 201. It also incorporates a signal processing algorithm to measure defect size by changing the electrode voltage. The processing unit 105 uses a low-power ARM (Advanced RISC Machine) microcontroller as its core, integrating a 24-bit ADC (Analog-to-Digital Converter), signal conditioning circuitry, and 8GB of Flash memory.

[0037] As can be seen, the signal conditioning module filters, amplifies, and reduces the noise of the weak ferrofluid induction signals collected by the upper and lower electrode plates. Then, the analog-to-digital conversion module accurately converts the analog detection signal into a digital signal. Finally, the storage module saves the detection data locally in real time. The collaborative work of each module can effectively suppress electromagnetic interference and signal attenuation caused by the complex working conditions inside the pipeline, improve the integrity of the detection signal and the sampling accuracy. No external processing equipment is required. The structure is highly integrated and the wiring is simple, which is suitable for the use of pipeline inspection devices that are in a confined and narrow space and require low power consumption for autonomous operation.

[0038] Figure 5 This is a flowchart illustrating a pipeline defect detection method provided by an embodiment of the present invention. This embodiment is applicable to situations where a ferromagnetic fluid pipeline internal inspection system detects defects within a pipeline. The method can be executed by the processing unit of the ferromagnetic fluid pipeline internal inspection system, which can be implemented in hardware and / or software.

[0039] See Figure 5 The pipeline defect detection method shown includes: S501. Obtain the voltage signal monitored in real time by the ferromagnetic fluid pipeline internal inspection system during its operation inside the pipeline to be inspected; the ferromagnetic fluid pipeline internal inspection system is driven to move by the medium inside the pipeline to be inspected.

[0040] The process involves placing a ferrofluid pipeline inspection system inside the pipeline to be inspected and introducing a transmission medium, such as oil or gas, into the pipeline. This medium drives the ferrofluid pipeline inspection system to move. As the ferrofluid pipeline inspection device within the system moves continuously, its upper and lower electrodes continuously sense and generate voltage changes. The real-time monitored voltage signal is the electrode voltage that fluctuates due to pipeline defects and changes in the magnetic field. The ferrofluid pipeline inspection device slowly moves inside the pipeline, establishing a stable background magnetic field with the permanent magnet. When the device moves to a defect location on the pipeline wall, such as corrosion or cracks, the magnetic field at that defect is distorted. The ferrofluid detection unit senses this change in the magnetic field at its location and accordingly changes its shape and conductivity. This change in the ferrofluid conductivity causes a change in its resistance, which in turn leads to a change in the voltage value on its two micro-electrodes. At this time, the upper and lower electrode plates of the ferrofluid pipeline internal detection device induce a constantly changing weak voltage, and transmit the induced voltage signal to the processing unit. The processing unit collects the voltage signals of all ferrofluid detection units in real time and synchronously.

[0041] The processing unit acquires and records the voltage signals induced by the upper and lower electrode plates of the ferrofluid pipeline internal inspection device. The processing unit obtains the voltage signals monitored in real time by the upper and lower electrode plates of the ferrofluid pipeline internal inspection device. Specifically, the processing unit acquires the original analog signal, performs signal conditioning to obtain a pre-processed signal, and then performs analog-to-digital conversion to obtain a digital signal, which is then identified as a voltage signal. Signal conditioning may include amplification, filtering and noise reduction, impedance matching, and waveform normalization.

[0042] S502. Determine the defect detection result of the pipeline to be inspected based on the real-time monitored voltage signal.

[0043] This process involves detecting defects in the pipeline based on real-time monitored voltage signals. Specifically, it involves detecting the presence and location of defects. The defect detection results can include the presence and location of defects.

[0044] The technical solution of this invention involves real-time sensing and acquisition of voltage signals caused by defects in the inner wall of a pipeline using a ferrofluid pipeline internal inspection system. Specifically, defect detection is achieved by sensing the magnetic field of the defect through ferrofluid, which is extremely sensitive to changes in magnetic fields. Through a finely arrayed array of ferrofluid pores, minute defects can be precisely identified and quantified with high spatial resolution, facilitating accurate defect identification and contour reconstruction. Simultaneously, the ferrofluid pipeline internal inspection device can replace the bulky coil and iron core structure of traditional pipeline internal detectors, achieving lightweight internal inspection equipment. The ferrofluid pipeline internal inspection system then processes the acquired signals to obtain the defect... The defect detection system enables on-site signal acquisition, real-time processing, and autonomous identification, eliminating the need for external pipeline equipment. This significantly shortens the signal transmission path, effectively avoids interference from complex electromagnetic environments and media within the pipeline, and improves the stability and accuracy of defect signal acquisition. Furthermore, it integrates detection acquisition and data processing into a compact and highly automated system. It can autonomously complete pipeline defect identification, parameter analysis, and result storage, making it suitable for confined and enclosed pipeline environments where real-time external wiring is not feasible. The system can also accurately locate defects, determine defect types and damage levels based on the detection results, thereby enhancing the overall efficiency and reliability of pipeline internal inspections.

[0045] In an optional embodiment, determining the defect detection result of the pipeline under inspection based on the real-time monitored voltage signal includes: acquiring a real-time voltage sequence based on the real-time monitored voltage signal; acquiring a reference voltage value obtained from the calibration of the ferrofluid pipeline internal inspection system; comparing each real-time voltage value in the real-time voltage sequence with the reference voltage value to obtain a voltage comparison result of the real-time voltage value; determining that the pipeline under inspection has a defect when the voltage comparison result of a real-time voltage value meets the voltage anomaly condition; and determining the location and degree of the defect in the pipeline under inspection based on the voltage comparison results of each real-time voltage value.

[0046] The real-time voltage sequence can be voltage values ​​arranged in chronological order of acquisition. The reference voltage value can be the voltage value of a defect-free pipeline obtained through calibration. In some embodiments, preparation and calibration of the device are required before defect detection. The assembled ferrofluid pipeline internal inspection system is installed on the corresponding section of the pipeline internal detector. The ferrofluid pipeline internal inspection system is run on a defect-free standard pipe section or test block, and the reference voltage value of each ferrofluid detection unit is recorded to complete the system calibration.

[0047] The difference between the real-time voltage value and the reference voltage value is calculated as the voltage comparison result. If the absolute value of the difference is greater than a preset difference threshold, the voltage anomaly condition is determined to be met. If the absolute value of the difference is less than or equal to the preset difference threshold, the voltage anomaly condition is determined not to be met. The voltage anomaly condition is used to detect whether there is a defect at the point corresponding to the real-time voltage value; specifically, it determines whether the difference is greater than the difference threshold. If the difference of a certain real-time voltage value is greater than or equal to the difference threshold, the difference of that real-time voltage value is obtained, and the size and direction of the defect are determined as the defect severity. The distance from the time point corresponding to the real-time voltage value to the data collected by the detection unit is obtained, and the defect location is determined.

[0048] It is evident that by using the standard voltage value of a defect-free pipeline as a reference, systematic errors caused by the environment, magnetic field, and installation deviations can be offset. The voltage comparison results can accurately quantify the size and damage level of defects such as corrosion or dents, improving the accuracy and comparability of defect severity assessment. At the same time, the distance detection unit can record the travel distance in real time, accurately mapping each voltage anomaly signal to the actual axial position of the pipeline. This achieves a combination of quantitative analysis of defect severity and precise location of defect points, eliminating the need for subsequent additional retesting and verification, simplifying the data analysis process, and improving the efficiency and accuracy of pipeline defect investigation, operation, and maintenance.

[0049] In an optional embodiment, determining the location of a defect in the pipeline to be inspected based on the voltage comparison results of each of the real-time voltage values ​​includes: acquiring a mileage data sequence corresponding to the real-time voltage sequence; the mileage data sequence is obtained by mileage wheel detection in the ferrofluid pipeline internal inspection system; and acquiring mileage data corresponding to real-time voltage values ​​whose voltage comparison results satisfy the voltage anomaly conditions from the mileage data sequence to determine the location of a defect in the pipeline to be inspected.

[0050] The system integrates a distance detection unit and a ferrofluid detection unit, which synchronously collect data in real time. Based on the distance detected by the distance detection unit and the timing of the data acquisition, a distance sequence corresponding to the test voltage sequence is generated, with each real-time voltage value corresponding to a specific distance. This distance represents the travel distance of the ferrofluid pipeline inspection system within the pipeline. When an abnormal voltage value is found, the corresponding distance can be retrieved from the distance sequence and used as the location of the pipeline defect.

[0051] In one example, voltage is sampled every 0.5 meters, resulting in a real-time voltage sequence: [0.82V, 0.83V, 1.25V, 0.81V, 0.82V]. The distance detection unit synchronously records the corresponding travel distance, generating a distance sequence: [10m, 10.5m, 11m, 11.5m, 12m]. If 1.25V is the real-time voltage value that meets the voltage anomaly condition, and the distance corresponding to 1.25V is 11m, it indicates that there is an inner wall defect at the 11-meter mark of the pipeline under inspection.

[0052] It can be seen that by filtering the distances corresponding to the actual voltage values ​​that meet the voltage anomaly conditions from the distance sequences corresponding to the real-time voltage sequences, the abnormal voltage signals and mileage distances can be bound together. The defects can be identified from the voltage anomalies, and the specific locations of the defects in the pipeline can be identified from the corresponding distances, thus achieving defect qualitative and precise location.

[0053] In an optional embodiment, determining the degree of defect in the pipeline to be inspected based on the voltage comparison results of each of the real-time voltage values ​​includes: determining the degree of defect in the pipeline to be inspected based on the difference between the real-time voltage value that satisfies the voltage anomaly condition and the reference voltage value.

[0054] Generally, the larger the difference, the greater the defect severity; the smaller the difference, the less severe the defect. For example, a difference ≤ 0.1V indicates a minor defect; 0.1V < difference ≤ 0.3V indicates a moderate defect; and a difference > 0.3V indicates a severe defect. A real-time voltage value of 0.85V with a voltage difference of 0.05V indicates a minor corrosion defect; a real-time voltage value of 1.00V with a voltage difference of 0.20V indicates a moderate pitting defect; and a real-time voltage value of 1.20V with a voltage difference of 0.40V indicates a severe crack or large-area corrosion defect.

[0055] Furthermore, since the permanent magnet components are evenly arranged along the circumference of the fixed components, these multiple permanent magnet components divide the circumference into several detection sectors. Each sector corresponds to an independent set of ferrofluid detection units, each outputting a separate voltage signal. If a defect is found in a particular location, only the electrode voltage corresponding to that location will show a significant shift, while the voltage in other normal locations will remain essentially unchanged.

[0056] The circumferential profile of a defect can be determined by detecting circumferential differences using a ferromagnetic conductor detection array: by comparing the voltage difference distribution of all electrodes around the circumference: only a small segment of the voltage is abnormal, indicating a point-like small defect; all electrodes on a continuous half-circumference are abnormal, indicating arc-shaped and strip-shaped defects; synchronous voltage changes throughout the circumference indicate an annular circumferential defect.

[0057] The longitudinal length can also be determined by continuous scanning along the axial (length direction): the ferromagnetic fluid pipeline inspection device moves forward and continuously samples, and the length of the abnormal voltage is the corresponding length of the defect along the pipeline.

[0058] In summary, by combining the circumferential range, axial length, and difference magnitude, a two-dimensional profile or even an approximate three-dimensional shape of the defect can be fitted.

[0059] For example, six sets of permanent magnet components, numbered 1-6, are evenly arranged around the circumference of the pipe. The reference voltage value is 0.8V for all of them. During testing, the voltage of electrodes 2 and 3 jumps to 1.15V, while the voltage of electrodes 1, 4, 5, and 6 remains close to 0.8V. This indicates that the defect is concentrated on the side of the pipe corresponding to electrodes 2 and 3, with a relatively small circumferential range. As the ferrofluid pipe inspection device moves forward, this abnormal voltage persists for a distance of 1.2 meters. A large voltage difference indicates a large corrosion depth. Based on this, a strip-shaped localized corrosion defect approximately 1.2 meters long on the side of the pipe is determined, directly identifying the defect's location, length, width, approximate shape, and severity.

[0060] By arranging multiple sets of ferromagnetic conductor detection arrays and electrode plates evenly along the circumference of the pipeline, induced voltage signals in each circumferential direction can be collected independently. The distribution of voltage difference between electrodes in different directions is used to characterize the circumferential coverage of the defect. Combined with the axial length of the voltage abnormality zone during the movement of the internal inspection device, and then matching the voltage difference amplitude to characterize the depth of defect damage, the contour size, extension shape and overall shape of the pipeline defect to be inspected can be accurately restored.

[0061] The processed defect information, along with the original voltage data, is stored in the storage module of the processing unit. After the inspection is completed, the ferrofluid pipeline internal inspection system is retrieved, the data is read, and further analysis is performed using the inversion algorithm.

[0062] It can be seen that by using the magnitude of the voltage difference to characterize the severity of the magnetic field distortion and ferrofluid distribution changes in the inner wall of the pipeline, the larger the difference, the more obvious the damage and deformation of the inner wall of the pipeline, thereby quantitatively determining the defect level and damage degree of the pipeline to be inspected.

[0063] This invention addresses the problems of bulky equipment and insufficient detection capability for minute defects in existing pipeline inspection technologies by providing a compact and lightweight pipeline inspection device. It simplifies the inspection structure by utilizing ferrofluid as the sensitive medium, replacing or partially replacing traditional magnetic flux leakage (MFL) detection sections. Furthermore, it provides a defect detection method based on the coupling effect of ferrofluid morphology and electrical properties. When a defect in the pipeline causes local magnetic field distortion, the shape of the ferrofluid changes, its conductivity changes, and the voltage of the electrodes on both sides changes. This allows for highly sensitive sensing and conversion of the magnetic field change near the defect into a measurable electrical signal. Through an arrayed sensor design, it achieves accurate identification and quantification of circumferential and axial defects in the pipeline, improving the resolution and reliability of the inspection.

[0064] Figure 6This is a schematic diagram of a pipeline defect detection device provided in an embodiment of the present invention. This embodiment of the present invention is applicable to the signal processing of a processing unit in a ferromagnetic fluid pipeline internal inspection system. The device can execute pipeline defect detection methods and can be implemented in hardware and / or software. The device can be configured within the processing unit of a ferromagnetic fluid pipeline internal inspection system.

[0065] See Figure 6 The video data transmission device shown includes: The voltage acquisition subunit 601 is used to acquire the voltage signal monitored in real time by the ferromagnetic fluid pipeline internal inspection system during its operation inside the pipeline to be inspected; the ferromagnetic fluid pipeline internal inspection system is driven to move by the medium inside the pipeline to be inspected. The defect detection subunit 602 is used to determine the defect detection result of the pipeline to be inspected based on the voltage signal monitored in real time.

[0066] The technical solution of this invention involves real-time sensing and acquisition of voltage signals caused by defects in the inner wall of a pipeline using a ferrofluid pipeline internal inspection system. Specifically, defect detection is achieved by sensing the magnetic field of the defect through ferrofluid, which is extremely sensitive to changes in magnetic fields. Through a finely arrayed array of ferrofluid pores, minute defects can be precisely identified and quantified with high spatial resolution, facilitating accurate defect identification and contour reconstruction. Simultaneously, the ferrofluid pipeline internal inspection device can replace the bulky coil and iron core structure of traditional pipeline internal detectors, achieving lightweight internal inspection equipment. The ferrofluid pipeline internal inspection system then processes the acquired signals to obtain the defect... The defect detection system enables on-site signal acquisition, real-time processing, and autonomous identification, eliminating the need for external pipeline equipment. This significantly shortens the signal transmission path, effectively avoids interference from complex electromagnetic environments and media within the pipeline, and improves the stability and accuracy of defect signal acquisition. Furthermore, it integrates detection acquisition and data processing into a compact and highly automated system. It can autonomously complete pipeline defect identification, parameter analysis, and result storage, making it suitable for confined and enclosed pipeline environments where real-time external wiring is not feasible. The system can also accurately locate defects, determine defect types and damage levels based on the detection results, thereby enhancing the overall efficiency and reliability of pipeline internal inspections.

[0067] Optionally, the defect detection subunit 602 is specifically used for: Obtain the real-time voltage sequence based on the real-time monitored voltage signal; Obtain the reference voltage value obtained from the calibration of the ferromagnetic fluid pipeline internal inspection system; For each real-time voltage value in the real-time voltage sequence, the real-time voltage value is compared with the reference voltage value to obtain the voltage comparison result of the real-time voltage value; When the voltage comparison result of the real-time voltage value meets the voltage anomaly condition, it is determined that the pipeline to be tested has a defect; Based on the voltage comparison results of each real-time voltage value, the location and degree of defects in the pipeline to be inspected are determined.

[0068] Optionally, the defect detection subunit 602 is specifically used for: Obtain the distance sequence corresponding to the real-time voltage sequence; the distance sequence is obtained by the distance detection unit in the ferromagnetic fluid pipeline internal inspection system. The distances corresponding to the real-time voltage values ​​that meet the voltage anomaly conditions are obtained from the distance sequence to determine the location of defects in the pipeline to be inspected.

[0069] Optionally, the defect detection subunit 602 is specifically used for: The degree of defect in the pipeline to be inspected is determined based on the difference between the real-time voltage value that meets the voltage anomaly condition and the reference voltage value, according to the voltage comparison results.

[0070] The pipeline defect detection device provided in this embodiment of the invention can execute the pipeline defect detection method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0071] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0072] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An internal inspection device for ferromagnetic fluid pipelines, characterized in that, include: The system comprises a fixed assembly, multiple permanent magnet assemblies, and multiple ferromagnetic conductor detection arrays. Each permanent magnet assembly is mounted on the outer wall of the fixed assembly, with its south pole facing the fixed assembly. The ferromagnetic conductor detection arrays are mounted at the north pole of the corresponding permanent magnet assembly. Each ferromagnetic conductor detection array includes multiple ferrofluid detection units, each ferrofluid detection unit comprising an upper electrode plate, a ferrofluid pore, and a lower electrode plate. The ferrofluid pore is positioned between the upper and lower electrode plates and is sealed and filled with ferrofluid.

2. The ferromagnetic fluid pipeline internal inspection device according to claim 1, characterized in that, Also includes: A distance detection unit is connected to the fixed component and is used to determine the movement distance of the fixed component.

3. The internal inspection device for ferromagnetic fluid pipelines according to claim 1, characterized in that, The magnetic fluid pores are filled with ferromagnetic fluid wrapped in a polymer film, and an upper or lower electrode sheet is mounted on the surface of the high-resolution film.

4. The internal inspection device for ferromagnetic fluid pipelines according to claim 1, characterized in that, The fixed component has a hollow cylindrical structure, and the permanent magnet components are evenly arranged along the circumference of the fixed component.

5. An internal inspection system for ferromagnetic fluid pipelines, characterized in that, It includes a ferromagnetic fluid pipeline internal inspection device and a processing unit as described in any one of claims 1-4; the processing unit is connected to the upper electrode plate and the lower electrode plate in the ferromagnetic fluid pipeline internal inspection device.

6. The ferromagnetic fluid pipeline internal inspection system according to claim 5, characterized in that, The processing unit includes: an analog-to-digital conversion module, a signal conditioning module, and a storage module.

7. A method for detecting pipeline defects, characterized in that, The system applied to the ferromagnetic fluid pipeline internal inspection system as described in claim 5 or 6 includes: The voltage signal monitored in real time by the ferromagnetic fluid pipeline internal inspection system during its operation inside the pipeline to be inspected is acquired; the ferromagnetic fluid pipeline internal inspection system is driven to move by the medium inside the pipeline to be inspected. The defect detection result of the pipeline under test is determined based on the real-time monitored voltage signal.

8. The method according to claim 7, characterized in that, The step of determining the defect detection result of the pipeline under inspection based on the real-time monitored voltage signal includes: Obtain the real-time voltage sequence based on the real-time monitored voltage signal; Obtain the reference voltage value obtained from the calibration of the ferromagnetic fluid pipeline internal inspection system; For each real-time voltage value in the real-time voltage sequence, the real-time voltage value is compared with the reference voltage value to obtain the voltage comparison result of the real-time voltage value; When the voltage comparison result of the real-time voltage value meets the voltage anomaly condition, it is determined that the pipeline to be tested has a defect; Based on the voltage comparison results of each real-time voltage value, the location and degree of defects in the pipeline to be inspected are determined.

9. The method according to claim 8, characterized in that, The step of determining the location of defects in the pipeline to be inspected based on the voltage comparison results of each of the real-time voltage values ​​includes: Obtain the distance sequence corresponding to the real-time voltage sequence; the distance sequence is obtained by the distance detection unit in the ferromagnetic fluid pipeline internal inspection system. The distances corresponding to the real-time voltage values ​​that meet the voltage anomaly conditions are obtained from the distance sequence to determine the location of defects in the pipeline to be inspected.

10. The method according to claim 8, characterized in that, The step of determining the degree of defect in the pipeline to be inspected based on the voltage comparison results of each of the real-time voltage values ​​includes: The degree of defect in the pipeline to be inspected is determined based on the difference between the real-time voltage value that meets the voltage anomaly condition and the reference voltage value, according to the voltage comparison results.

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