Pipeline nondestructive testing device and testing method

Abstract

The application relates to the technical field of pipeline detection equipment, and provides a pipeline nondestructive detection device and a detection method, which comprise a rack, a rotating wheel base for supporting a pipeline and driving the pipeline to rotate is arranged on the rack; a moving frame is movably arranged on the rack and can move close to the pipeline; an acoustic wave probe is arranged on the moving frame and can move along with the moving frame and abut against an outer wall of the pipeline; a fence assembly is arranged on the moving frame, the fence assembly is provided with an abutting assembly matched with the outer wall of the pipeline at the bottom, and the abutting assembly is configured to: after the abutting assembly abuts against the outer wall of the pipeline, the outer wall of the pipeline and the fence assembly form a coupling liquid containing cavity, the coupling liquid containing cavity is communicated with a coupling liquid supply assembly, and the acoustic wave probe is located in the coupling liquid containing cavity. The technical problem of a large amount of coupling liquid used in the acoustic wave detection process in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of pipeline inspection equipment technology, specifically to a pipeline non-destructive testing device and testing method. Background Technology

[0002] Non-destructive testing (NDT) equipment for pipelines includes devices for inspecting single sections of pipeline during the pipeline manufacturing stage and devices for inspecting continuous pipelines during installation and operation. Currently, acoustic testing is the most widely used method. Acoustic testing can not only detect internal structural defects in pipelines, but also avoids the radiation effects on personnel compared to X-ray testing.

[0003] In existing technologies, the testing device for a single section of pipe during the pipe manufacturing stage includes a pipe drive wheel base. This base not only supports the pipe but also drives the pipe to rotate in one direction at a set speed through contact with the pipe's outer wall. An acoustic probe is movably mounted on one side of the drive wheel base via a movable frame. The probe is moved by the frame to contact the pipe's outer wall and moves along the pipe's axis. To prevent gaps between the probe and the pipe's outer wall during testing, a coupling fluid outlet is provided on one side of the probe. The coupling fluid flowing out of this outlet forms a liquid film between the probe and the outer wall, thus preventing gaps from causing deviations in the test results.

[0004] However, in actual use, the aforementioned pipeline non-destructive testing device suffers from problems such as coupling fluid splashing due to pipeline rotation, and the need for continuous replenishment of coupling fluid during the movement of the acoustic probe, resulting in a large consumption of coupling fluid. Since coupling fluids are typically lubricating oil, deionized water, or purified water, the excessive use of coupling fluid increases the cost of pipeline non-destructive testing. Summary of the Invention

[0005] To overcome the above-mentioned defects, embodiments of the present invention provide a pipeline non-destructive testing device and testing method, which solves the technical problem of large amount of coupling fluid used in the existing acoustic testing process.

[0006] According to one aspect, at least one embodiment of the present invention provides a pipeline non-destructive testing device, comprising: A frame, on which a rotating wheel base is provided for supporting the pipe and driving the pipe to rotate; A movable frame is movably mounted on the frame, and the movable frame is capable of moving closer to the pipe; An acoustic probe is mounted on the movable frame, and the acoustic probe can move with the movable frame and abut against the outer wall of the pipe. A fencing assembly is mounted on the movable frame. The bottom of the fencing assembly has an abutment component adapted to the outer wall of the pipe. The abutment component is configured such that after the abutment component abuts against the outer wall of the pipe, the outer wall of the pipe and the fencing assembly form a coupling fluid receiving cavity, and the coupling fluid receiving cavity is connected to a coupling fluid supply assembly. The acoustic probe is located inside the coupling fluid containment cavity, which is configured such that the radiating surface of the acoustic probe and the outer wall of the pipe corresponding to the coupling fluid containment cavity are always immersed in the coupling fluid.

[0007] For example, in at least one embodiment of the present invention, a pipeline non-destructive testing device further includes: A baffle is disposed on the inner wall of the coupling fluid receiving cavity. The baffle is configured to divide the coupling fluid receiving cavity into an inlet cavity and an outlet cavity that are connected at the bottom, so that the liquid in the coupling fluid receiving cavity can circulate.

[0008] For example, in a pipeline non-destructive testing device provided by at least one embodiment of the present invention, the enclosure assembly has an inlet communicating with the inlet chamber and an outlet communicating with the outlet chamber. The outlet is lower than the inlet and higher than the emitting surface of the acoustic probe, so that the coupling fluid in the outlet can be continuously discharged and the path of the coupling fluid flowing from the inlet chamber to the outlet chamber is maintained.

[0009] For example, in at least one embodiment of the present invention, a pipeline non-destructive testing device further includes: A porous flow equalization plate is disposed at the liquid inlet, which can disperse the liquid entering the coupling liquid receiving cavity.

[0010] For example, in a pipeline non-destructive testing device provided by at least one embodiment of the present invention, the enclosure assembly includes two longitudinal baffles and two transverse baffles. The length direction of the two longitudinal baffles is parallel to the rotation axis of the rotating wheel base, and the length direction of the two transverse baffles is perpendicular to the rotation axis of the rotating wheel base. The abutment assembly includes: Two flexible sealing strips are provided, one-to-one, at the bottom of the two longitudinal baffles and extending to the bottom of the transverse baffles located on both sides of the longitudinal baffles. The flexible sealing strips are used to slide and seal against the outer wall of the pipe. There are two expansion seals, which are arranged one-to-one at the bottom of the two horizontal baffles. The expansion seals can expand and slide to seal against the outer wall of the pipe.

[0011] For example, in a pipeline non-destructive testing device provided by at least one embodiment of the present invention, the flexible sealing strip includes an abutment portion and a deformable portion. The deformable portion is disposed at the bottom of the longitudinal baffle, and the abutment portion is disposed at the bottom of the deformable portion. The thickness of the deformable portion is smaller than that of the deformable portion, so that after the abutment portion abuts against the pipeline and receives force, the deformable portion can deform and rely on the deformation force to provide the abutment portion with a force close to the outer wall of the pipeline. The expansion seal is positioned on both sides of the deformable portions of the two flexible sealing strips so that the expansion seal can adapt to the deformation of the deformable portions.

[0012] For example, in at least one embodiment of the present invention, a pipeline non-destructive testing device further includes: A dynamic force loading unit is mounted on the movable frame, and the acoustic probe is mounted on the dynamic force loading unit. The dynamic force loading unit can apply an alternating driving force in the vertical direction to the acoustic probe so that the contact force between the acoustic probe and the outer wall of the pipe changes with a preset frequency and amplitude based on a preset bias force. A contact force dynamic measurement unit is disposed between the dynamic force loading unit and the acoustic probe, and is used to measure the pressure applied by the dynamic force loading unit to the acoustic probe; The controller controls the dynamic force loading unit based on the feedback signal from the contact force dynamic measurement unit, so that the instantaneous contact force between the acoustic probe and the outer wall of the pipe changes periodically at a fixed frequency.

[0013] For example, in a pipeline non-destructive testing device provided in at least one embodiment of the present invention, the dynamic force loading unit is a piezoelectric ceramic stack actuator or a voice coil motor, the preset frequency is 50Hz to 1kHz, and the amplitude of the alternating force component does not exceed 50% of the preset bias force.

[0014] For example, in a pipeline non-destructive testing device provided in at least one embodiment of the present invention, the contact force dynamic measurement unit is a PVDF piezoelectric film force sensor.

[0015] According to another aspect, at least one embodiment of the present invention also provides a method for non-destructive testing of pipelines, comprising performing non-destructive testing of pipelines using the aforementioned pipeline non-destructive testing device, including: S100: Place the pipe to be tested on the rotating wheel base so that the rotating wheel base can drive the pipe to rotate; S200: The moving frame moves the acoustic probe and the enclosure assembly to fit against the outer wall of the pipe, and processes the coupling fluid into the coupling fluid receiving cavity so that the coupling fluid completely submerges the emitting surface of the acoustic probe; S300: Activate the acoustic probe and move the moving frame along the axial direction of the pipe.

[0016] The beneficial effects of this invention are as follows: In this invention, a containment assembly 500 is installed on the movable frame 300, and the bottom of the containment assembly 500 has an abutment assembly 600 adapted to the outer wall of the pipe. When the movable frame 300 moves the acoustic probe 400 close to the pipe, the abutment assembly 600 abuts against the outer wall of the pipe, forming a coupling fluid receiving cavity 510 between the outer wall of the pipe and the containment assembly 500. This coupling fluid receiving cavity 510 is connected to the coupling fluid supply assembly, and the radiating surface of the acoustic probe 400 and the outer wall of the pipe corresponding to the coupling fluid receiving cavity 510 are always immersed in the coupling fluid.

[0017] The containment assembly 500 and the abutment assembly 600 enclose a relatively closed space in a localized area of ​​the outer wall of the pipe. After the coupling fluid is injected into this space, the side walls of the containment assembly 500 and the abutment assembly 600 physically block the coupling fluid. When the pipe rotates, the coupling fluid is constrained by the circumferential side walls of the containment assembly 500 and cannot be thrown out of the detection area by centrifugal force. The coupling fluid is confined within the coupling fluid receiving cavity 510 for recycling or slow consumption, avoiding the problem of coupling fluid splashing and loss in the prior art, thereby significantly reducing the amount of coupling fluid consumed during the detection process and lowering the detection cost. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of the present invention and these drawings without any creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 A schematic diagram of the left-side structure of an embodiment; Figure 3 for Figure 2 Enlarged structural diagram at point A in the middle; Figure 4 for Figure 1 A schematic diagram of the main view structure of an embodiment; Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure in the middle BB direction; Figure 6 for Figure 5 Enlarged structural diagram at point C; Figure 7 for Figure 5 A schematic diagram of the structure during detection in an embodiment; Figure 8 for Figure 7Enlarged structural diagram at point D; In the diagram: 100, frame; 200, rotating wheel base; 300, moving frame; 400, acoustic probe. 500. Enclosure assembly; 510. Coupling fluid receiving cavity; 511. Inlet cavity; 512. Outlet cavity; 513. Inlet port; 514. Outlet port; 520. Baffle plate; 530. Porous flow equalization plate; 540. Longitudinal baffle; 550. Transverse baffle. 600, Abutment component; 610, Flexible sealing strip; 611, Abutment part; 612, Deformable part; 620, Expansion seal. 700. Dynamic force loading unit. Detailed Implementation The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0020] To keep the drawings concise, each drawing only schematically shows the parts relevant to the invention; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0021] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] In pipe manufacturing, ultrasonic testing is widely used due to its radiation-free operation and ability to effectively detect internal defects. Typical testing equipment uses a rotating wheel base to drive the pipe to rotate, while the ultrasonic probe moves axially along the pipe and performs a spiral scan against the outer wall. To ensure effective sound wave transmission, a coupling fluid needs to be continuously supplied between the probe and the pipe wall. However, the high-speed rotation of the pipe easily throws out the coupling fluid, leading to an unstable liquid film, high fluid consumption, and high costs. This invention aims to provide a non-destructive testing device and method for pipelines that effectively saves coupling fluid and maintains a stable coupling environment.

[0026] like Figures 1-8 As shown, this invention illustrates a non-destructive testing device for pipelines according to an embodiment of the present invention, including a frame 100, a rotating wheel base 200, a movable frame 300, an acoustic probe 400, and a containment assembly 500. The frame 100 serves as the supporting foundation for the entire device, on which the rotating wheel base 200 is mounted. The rotating wheel base 200 includes at least two sets of parallel supporting rollers, each set of which can be driven to rotate by an independent drive device. Different sets of supporting rollers can also be driven together by a single drive device through chain, sprocket, synchronous belt, synchronous pulley, or gear meshing. The rotating wheel base 200 supports the pipe being tested and drives it to rotate uniformly around its own axis. The movable frame 300 is movably mounted on the frame 100 via guide rails and a drive mechanism, allowing it to move horizontally along the pipe's axial direction towards or away from the pipe. Figure 1 As shown, the movable frame 300 includes a horizontally movable base that can move closer to or further away from the pipeline, driven by a drive unit and a lead screw. A sliding seat that slides along the pipeline axis is mounted on the horizontally movable base, driven by another independent drive unit and lead screw. A lifting seat that slides along the conveying direction is mounted on the sliding seat; the lifting seat can be activated by an electric cylinder. Through three-dimensional movement, the movable frame 300 can move to any position according to the size of the pipeline, and drive the acoustic probe 400 to adhere to the outer wall of the pipeline for detection.

[0027] The acoustic probe 400 is bolted to the lifting seat of the movable frame 300 and can move with it. During testing, the movable frame 300 moves the acoustic probe 400 above the pipe, and then the lifting seat descends, so that the front end of the acoustic probe 400 abuts against the outer wall of the pipe.

[0028] The enclosure assembly 500 is fixed to the lifting seat of the movable frame 300 and surrounds the acoustic probe 400. An abutment assembly 600, adaptable to the outer wall of the pipe, is installed at the bottom of the enclosure assembly 500. When the movable frame 300 descends to its position and the abutment assembly 600 is tightly fitted against the outer wall of the pipe, a relatively closed coupling fluid receiving cavity 510 is formed between the inner wall of the enclosure assembly 500 and the outer wall of the pipe. This cavity is connected to an external coupling fluid supply assembly via a pipeline.

[0029] During testing, the coupling fluid is injected into the coupling fluid receiving cavity 510, completely immersing the emitting surface of the acoustic probe 400 and the corresponding local pipe wall below it. Due to the physical obstruction of the containment assembly 500 and the abutment assembly 600, even if the pipe rotates at high speed, the coupling fluid is confined within the receiving cavity and will not be thrown out. The coupling fluid is deionized water or purified water, and has undergone defoaming treatment. The coupling receiving cavity creates a stable, bubble-free liquid immersion coupling environment between the probe and the pipe wall, ensuring the stability of the detection signal. More importantly, the coupling fluid can be recycled or slowly consumed within the cavity, reducing coupling fluid splash loss and continuous replenishment, thus lowering testing costs.

[0030] To further optimize the utilization efficiency and coupling quality of the coupling fluid, such as Figure 4 , Figure 5 As shown, one or more baffles 520 are provided inside the coupling fluid receiving cavity 510. The baffles 520 divide the receiving cavity into an inlet cavity 511 and an outlet cavity 512 that are connected at the bottom. The enclosure assembly 500 has an inlet port 513 that communicates with the inlet cavity 511 and an outlet port 514 that communicates with the outlet cavity 512. The height of the outlet port 514 is designed to be lower than that of the inlet port 513, but higher than the emitting surface of the acoustic probe 400. In this way, under the drive of gravity or an external pump, fresh coupling fluid enters the inlet cavity 511 from the inlet port 513, flows downward through the gap between the probe and the tube wall, enters the outlet cavity 512 from the bottom connection, and then flows upward through the outlet port 514 to be discharged. This U-shaped flow path forms a liquid circulation, which can continuously remove the heat generated by the operation or friction of the probe and any tiny air bubbles that may intrude, maintaining the optimal acoustic performance of the coupling fluid in the cavity. Meanwhile, the outlet 514 is higher than the probe's radiation surface, ensuring that the probe is always submerged regardless of the flow.

[0031] In this flow path, a porous flow equalization plate 530 is preferably provided at the inlet 513. The liquid flow entering from the inlet 513 may be impactful; if it directly impacts the probe or pipe wall, it may cause splashing or bubbles. The porous flow equalization plate 530 can disperse the incoming liquid into multiple smooth and uniform fine streams, allowing it to be injected into the cavity in a near-laminar state, further ensuring the stability of the liquid field.

[0032] The abutment component 600 is crucial for forming a stable receiving cavity. It must ensure a good seal while allowing the abutment component to slide relative to the pipe without scratching the pipe wall. This invention proposes a combined flexible sealing solution.

[0033] Reference Figure 3 and Figure 5 The sidewalls of the enclosure assembly 500 are mainly composed of two longitudinal baffles 540 and two transverse baffles 550. The length direction of the two longitudinal baffles 540 is parallel to the pipe axis, while the length direction of the two transverse baffles 550 is perpendicular to the pipe axis. Correspondingly, the abutment assembly 600 is composed of two seals with different properties.

[0034] First, a flexible sealing strip 610 is installed at the bottom of each of the two longitudinal baffles 540. The length of this flexible sealing strip 610 not only covers the entire length of the longitudinal baffles 540 but also extends to the bottom of the two transverse baffles 550. The flexible sealing strip 610 is vertically divided into a deformable portion 612 and an abutting portion 611 located at its bottom. The deformable portion 612 is thinner and is directly connected to the baffle by adhesive or fasteners; the abutting portion 611 is thicker and is the actual contact portion with the pipe wall. When the cavity is pressed down, the abutting portion 611 contacts the pipe wall and is compressed. The thinner deformable portion 612 will first undergo elastic bending deformation, and the resulting rebound force will, in turn, gently and consistently press the abutting portion 611 against the pipe wall surface.

[0035] like Figure 7 , Figure 8 As shown, during the descent of the lifting seat, the contact part 611 first contacts the outer wall of the pipe. As the lifting seat continues to descend, the outer wall of the pipe where the contact part 611 contacts the outer wall has curvature. Therefore, the deformable part 612 deforms in the direction away from the acoustic probe. During this process, the contact part 611 is always in close contact with the outer wall of the pipe due to the influence of the deformable part 612, until the emitting surface of the acoustic probe contacts the outer wall of the pipe and is immersed in the coupling fluid.

[0036] Secondly, at the bottom of each of the two transverse baffles 550, an expansion seal 620 is provided. Unlike the flexible sealing strip 610, which relies on its own deformation force for sealing, the expansion seal 620 is an elastic bladder with an internal inflation chamber. It expands after being inflated by an external air source and actively adheres to the pipe wall. The two ends of the expansion seal 620 overlap with the deformed portions 612 of the flexible sealing strips 610 on both sides, and are sealed and fixed together in the overlapping area by methods such as vulcanization. When the expansion seal 620 is inflated, it pulls or moves along with the deformed portions 612, ensuring that a complete, leak-free closed-loop flexible sealing system is formed throughout the entire bottom circumference from the longitudinal baffle to the transverse baffle. This combined structure takes into account both wear-resistant sliding sealing along the pipe axis and active pressure-boosting sealing in the circumferential direction.

[0037] Furthermore, to ensure the service life of the contact component 600, the flexible sealing strip 610 can be made of wear-resistant polyurethane, oil-resistant nitrile rubber, or water-resistant silicone, etc., and the expansion seal 620 is composed of polytetrafluoroethylene (PTFE) fabric or film with a low coefficient of friction.

[0038] The above-described implementation method solves the coupling stability problem, but for highly dangerous closed microcracks in pipes, conventional constant pressure contact ultrasonic testing often fails to effectively identify them due to the tight contact of the crack interface. To address this issue, this invention improves the driving method of the acoustic probe.

[0039] In a preferred embodiment of the present invention, the device further includes a dynamic force loading unit 700, a contact force dynamic measurement unit, and a controller.

[0040] like Figure 6 , Figure 8 As shown, the dynamic force loading unit 700 is connected in series between the movable frame 300 and the acoustic probe 400. It is no longer a simple fixed support, but a power source capable of applying vertical vibrations to the acoustic probe 400. The dynamic force loading unit 700 can be a fast-response piezoelectric ceramic stack actuator or a voice coil motor. The controller instructs it to generate an alternating driving force that dynamically varies in frequency and amplitude from 50Hz to 1kHz based on a preset bias force.

[0041] To ensure precise force control, a contact force dynamic measurement unit is coaxially connected in series between the dynamic force loading unit 700 and the acoustic probe 400. This unit preferentially employs a high-response-frequency PVDF piezoelectric film force sensor, capable of sensing and feeding back the instantaneous contact force waveform between the probe and the pipe wall to the controller in real time. The controller then performs closed-loop fine-tuning based on the feedback signal, ensuring that the actual applied force strictly follows the preset "constant bias force + high-frequency sinusoidal force" curve.

[0042] The bias force provides a stable average coupling pressure, ensuring the probe does not detach from the pipe wall. The amplitude of the superimposed high-frequency alternating force is controlled to not exceed 50% of the bias force, ensuring that the probe maintains positive pressure on the pipe wall at all times (even when vibrating to the trough of minimum force), preventing impact and cavitation bubbles. When this tiny dynamic force acts on a pipe wall with a closed crack, it causes the crack interface to periodically "breathe" open and close. This extremely weak mechanical disturbance modulates the ultrasonic waves penetrating the crack, causing their amplitude or phase to fluctuate at the same frequency. By extracting these modulation features through subsequent signal processing, closed cracks that cannot be detected by conventional methods can be separated from background noise, thereby improving the defect detection capability.

[0043] Regarding the control mode of the dynamic force loading unit 700, the controller can be set to a continuous alternating mode for high-sensitivity scanning of the entire length of the pipe; or it can be set to an intermittent trigger mode, which only activates dynamic force modulation for verification and property determination when a suspicious wall thinning area is detected by the conventional A-scan signal. This working mode can improve the overall detection speed while ensuring the detection rate.

[0044] During the testing process, the ultrasonic pulse repetition frequency of the acoustic probe 400 is much higher than the excitation frequency of the dynamic force loading unit 700. For example, the force modulation frequency is set to 200Hz, while the probe emits 4000 ultrasonic pulses per second. Within one complete force cycle, the probe will perform multiple transmissions and receptions, acquiring a series of time-varying A-scan signals.

[0045] The signal processing unit first extracts the echo amplitude and transit time in real time from the wave packets at specific depth locations within this series of A-scan signals. These two parameters fluctuate slightly with the periodic changes in dynamic contact force. For normal pipe wall regions, the echo amplitude fluctuations mainly exhibit the fundamental frequency component, which is the same as the force frequency, reflecting the linear response of the material within its elastic range. However, for regions with closed microcracks, the crack interface undergoes periodic "opening-closing" motion under alternating force, resulting in asymmetrical changes in contact stiffness within the tensile and compressive half-cycles. This nonlinear mechanical behavior causes significant higher harmonic components, such as second and third harmonic components, to appear in the echo amplitude fluctuations in addition to the fundamental frequency component.

[0046] Based on the aforementioned physical mechanism, the signal processing unit uses the excitation frequency of the dynamic force loading unit 700 as a reference to perform phase-locked demodulation or fast Fourier transform spectrum analysis on the echo amplitude envelope, extracting the DC component A0, the fundamental frequency modulation component A_f, and the higher harmonic modulation components A_{2f} and A_{3f}. Subsequently, a defect nonlinear modulation index η, used to characterize the intensity of defect nonlinear activity, is calculated: η= ×100% This index uses a ratio form, which can eliminate changes in the absolute amplitude of the signal caused by fluctuations in coupling efficiency or surface roughness of the pipe, and has good robustness.

[0047] After obtaining the nonlinear modulation index η, the defect judgment and auxiliary control output unit, combined with the conventional wall thickness measurement value d calculated from the ultrasonic flight time, executes the following comprehensive judgment logic: When the wall thickness d is within the acceptable tolerance range and η is lower than the preset threshold, the inspection location is determined to be in a healthy state, and a first control signal is output, for example, driving the sorting mechanism to classify the pipe into the qualified product channel. When the wall thickness d is lower than the lower limit of the acceptable range, but η is still lower than the threshold, it is determined that there is a volumetric defect at this location, such as corrosion pits, wall thinning, or slag inclusions, and a second control signal is output, indicating that the pipe needs to be downgraded or enter the manual re-inspection process. When η is higher than or equal to the preset threshold, regardless of whether the wall thickness d is acceptable, it is determined that there is a closed microcrack defect at this location. This is because even if the wall thickness is temporarily acceptable, closed cracks are very easy to propagate under subsequent pressure or fatigue conditions, which is extremely harmful. Therefore, a third control signal is output to directly trigger the rejection or isolation action. In particular, when the wall thickness d is too thin and η is higher than the threshold at the same time, it indicates that there is both significant wall thickness loss and active cracks at this location, which is the most dangerous condition. Rejection or isolation actions and alarm signals can be output.

[0048] Another embodiment of the present invention provides a pipeline non-destructive testing method, which utilizes the above-mentioned pipeline non-destructive testing device to perform non-destructive testing on the pipeline, including the following steps: S100: Place the pipe to be tested on the rotating wheel base 200 so that the rotating wheel base 200 can drive the pipe to rotate; S200: The moving frame 300 drives the acoustic probe 400 and the enclosure assembly 500 to fit against the outer wall of the pipe, and processes the coupling fluid into the coupling fluid receiving cavity 510 so that the coupling fluid completely immerses the emitting surface of the acoustic probe 400. S300: Activate the acoustic probe 400 and move the moving frame 300 along the axial direction of the pipe.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A non-destructive testing device for pipelines, characterized in that, include: A frame (100) is provided with a rotating wheel base (200) for supporting the pipe and driving the pipe to rotate. A movable frame (300) is movably mounted on the frame (100), and the movable frame (300) is movable to move closer to the pipe; A fencing assembly (500) is mounted on the movable frame (300). The bottom of the fencing assembly (500) has an abutment assembly (600) adapted to fit the outer wall of the pipe. The abutment assembly (600) is configured to abut against the outer wall of the pipe to form a coupling fluid receiving cavity (510). The coupling fluid receiving cavity (510) is used to communicate with a coupling fluid supply assembly. An acoustic probe (400) is mounted on the movable frame (300) and located in the coupling fluid containment cavity (510). When the outer wall of the pipe is in the detection state, the radiating surface of the acoustic probe (400) and the area to be tested on the outer wall of the pipe are always immersed in the coupling fluid in the coupling fluid containment cavity (510).

2. The pipeline non-destructive testing device according to claim 1, characterized in that, Also includes: A partition (520) is disposed inside the coupling fluid receiving cavity (510), the partition (520) being configured to divide the coupling fluid receiving cavity (510) into a bottom-connected inlet cavity (511) and an outlet cavity (512) so that the liquid in the coupling fluid receiving cavity (510) can circulate.

3. The pipeline non-destructive testing device according to claim 2, characterized in that, The enclosure assembly (500) has an inlet (513) communicating with the inlet chamber (511) and an outlet (514) communicating with the outlet chamber (512). The outlet (514) is lower than the inlet (513) and higher than the emitting surface of the acoustic probe (400) so that the coupling fluid in the outlet (514) can be continuously discharged and the emitting surface of the acoustic probe (400) is kept submerged in the coupling fluid.

4. The pipeline non-destructive testing device according to claim 3, characterized in that, Also includes: A porous flow equalization plate (530) is disposed at the liquid inlet (513), and the porous flow equalization plate (530) can disperse the liquid entering the coupling liquid receiving cavity (510).

5. The pipeline non-destructive testing device according to claim 1, characterized in that, The enclosure assembly (500) includes two longitudinal baffles (540) and two transverse baffles (550). The surfaces of the two longitudinal baffles (540) are parallel to the rotation axis of the rotating wheel base (200), and the surfaces of the two transverse baffles (550) are perpendicular to the rotation axis of the rotating wheel base (200). The abutment assembly (600) includes: Two flexible sealing strips (610) are provided at the bottom of the two longitudinal baffles (540) respectively, and extend to the bottom of the transverse baffles (550) located on both sides of the longitudinal baffles (540). The flexible sealing strips (610) are used to slide and seal against the outer wall of the pipe. Two expansion seals (620) are provided at the bottom of the two transverse baffles (550) respectively. The expansion seals (620) can expand and slide to seal against the outer wall of the pipe.

6. The pipeline non-destructive testing device according to claim 5, characterized in that, The flexible sealing strip (610) includes an abutment portion (611) and a deformable portion (612). The deformable portion (612) is disposed at the bottom of the longitudinal baffle (540), and the abutment portion (611) is disposed at the bottom of the deformable portion (612). The thickness of the deformable portion (612) is less than that of the deformable portion (612) so that after the abutment portion (611) abuts against the pipe and receives force, the deformable portion (612) can deform outward and rely on the deformation force to provide the abutment portion (611) with force close to the outer wall of the pipe. The expansion seal (620) is disposed on both sides inside the deformable portions (612) of the two flexible sealing strips (610) so that the expansion seal (620) can adapt to the deformation of the deformable portions (612).

7. The pipeline non-destructive testing device according to claim 1, characterized in that, Also includes: A dynamic force loading unit (700) is disposed on the movable frame (300), and the acoustic probe (400) is disposed on the dynamic force loading unit (700). The dynamic force loading unit (700) can apply a vertical alternating driving force to the acoustic probe (400) so that the contact force between the acoustic probe (400) and the outer wall of the pipe changes with a preset frequency and amplitude based on a preset bias force. A contact force dynamic measurement unit is disposed between the dynamic force loading unit (700) and the acoustic probe (400) for measuring the pressure applied by the dynamic force loading unit (700) to the acoustic probe (400); The controller controls the dynamic force loading unit (700) according to the feedback signal of the contact force dynamic measurement unit, so that the instantaneous contact force between the acoustic probe (400) and the outer wall of the pipe changes periodically at a fixed frequency.

8. A pipeline non-destructive testing device according to claim 7, characterized in that, The dynamic force loading unit (700) is a piezoelectric ceramic stack actuator or a voice coil motor, the preset frequency is 50Hz to 1kHz, and the amplitude of the alternating force component does not exceed 50% of the preset bias force.

9. A pipeline non-destructive testing device according to claim 7, characterized in that, The contact force dynamic measurement unit is a PVDF piezoelectric film force sensor.

10. A method for non-destructive testing of pipelines, comprising performing non-destructive testing of pipelines using the pipeline non-destructive testing device according to any one of claims 1 to 9, characterized in that, include: S100: Install the pipe to be tested onto the rotating wheel base (200) so that the rotating wheel base (200) can drive the pipe to rotate; S200: The moving frame (300) drives the acoustic probe (400) and the enclosure assembly (500) to fit against the outer wall of the pipe, and processes the coupling fluid into the coupling fluid receiving cavity (510) so that the coupling fluid completely immerses the emitting surface of the acoustic probe (400); S300: Activate the acoustic probe (400) and move the moving frame (300) along the axial direction of the pipe.

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