An online inspection device for oil pipeline welds based on magnetic particle testing

Abstract

This invention relates to the technical field of magnetic particle testing and discloses an online inspection device for oil pipeline welds based on magnetic particle testing. The device includes a flaw detector body with an internal electromagnetic yoke for generating a magnetic field, and contact rollers rotatably mounted on the bottom of the flaw detector body's support legs. A mounting groove is formed on the bottom surface of the flaw detector body, and a fixing rod is fixedly mounted on the inner wall of the mounting groove. A telescopic rod is elastically mounted on the wall of the fixing rod, and a sealing cylinder is fixedly mounted on the bottom surface of the telescopic rod. Two guide wheels for locating the weld are located at the bottom of the sealing cylinder, and elastic contact plates are fixedly mounted on the opposite surfaces of the two guide wheels. A pressure regulating component is installed inside the mounting groove. This device effectively improves the detection sensitivity of welds by actively utilizing the weld as a physical track for the flaw detector body's automatic tracking mechanism.

Description

Technical Field

[0001] This invention relates to the technical field of magnetic particle testing, and more particularly to an online inspection device for oil pipeline welds based on magnetic particle testing. Background Technology

[0002] As the "arteries" of national energy transportation, the safe and reliable operation of oil and gas pipelines is of paramount importance. Pipeline welded joints are the weakest link in the entire pipeline, and their quality directly determines the load-bearing capacity and service life of the pipeline system. Especially in high-pressure, harsh environments such as through-passage oil and gas pipelines, deep-sea oil and gas pipelines, and projects crossing major rivers, the pipelines face extremely high transmission pressures, complex stress states, and corrosive environments, placing almost stringent requirements on weld quality. These pipelines typically employ large-diameter, thick-walled designs, with weld widths reaching 40mm to 60mm or even wider, making them the most technically demanding and expensive type of pipeline to manufacture.

[0003] Currently, magnetic particle testing is widely used in quality control during pipeline manufacturing and construction due to its advantages such as ease of operation, intuitive display, and high sensitivity for detecting surface and near-surface cracks and incomplete penetration in ferromagnetic material pipelines. Among these technologies, the electromagnetic yoke method of magnetic particle testing is one of the mainstream techniques. Its core principle is based on electromagnetic induction: a magnetic field is generated by energizing the coil windings inside the equipment, and the iron core guides the concentrated output of the magnetic field, which is then introduced into the weld area being inspected through magnetic pole contacts. When a defect exists in the weld, the magnetic lines of force are distorted, creating a leakage magnetic field that attracts magnetic particles, forming visible magnetic traces, thereby locating the defect.

[0004] like Figure 1 As shown, a roller-type electromagnetic yoke flaw detector is characterized by its integrated design of the magnetic pole contact and the roller. The roller at the bottom of the device is not a simple walking wheel; its interior or the roller itself is made of a highly permeable magnetic material, directly serving as the output end of the magnetic field. This ingenious design combines magnetization and movement, enabling the device to roll stably on the surface of the inspected pipe, achieving continuous and efficient magnetization operations.

[0005] It is worth noting that, such as Figure 2 As shown, in pipeline welding practice, to ensure welding quality, bevels of specific shapes (such as V-shaped or U-shaped) are pre-machined on the contact surfaces of the two pipes to be welded. After welding, the filler metal (welding fluid) completely covers the bevel area, and due to the need to compensate for metal shrinkage and enhance joint strength, a raised structure significantly higher than the original surface of the base material is formed on the pipe surface, namely the "weld reinforcement". This continuous and smooth weld reinforcement forms a clear physical boundary between its two sides and the base material, naturally providing a "physical track" for detection equipment to identify and track.

[0006] However, even with this optimized equipment, magnetic particle testing of the aforementioned welds presents significant challenges, particularly the precise alignment and stable tracking of the testing equipment with the weld's "physical trajectory." Theoretically, the maximum leakage magnetic field is generated when the magnetic field lines are perpendicular to the defect's extension direction, resulting in the clearest defect indication. For pipe circumferential welds, the electromagnetic yoke device generates a magnetic field perpendicular or parallel to the weld direction via its roller-type magnetic poles to detect longitudinal and transverse defects. Regardless of the magnetization method used, the core prerequisite is that the line connecting the centers of the two roller magnetic poles must essentially coincide with the center of the weld reinforcement to ensure a uniform and ideally oriented magnetic field across the weld width.

[0007] In actual online inspection, because the rollers of a roller-type flaw detector only serve as support and movement components and cannot accurately sense and follow the center trajectory of the weld, the rollers are prone to positional deviation due to factors such as pipeline vibration and irregular weld width. When the flaw detector deviates from the weld center, the magnetic field it generates will be unevenly distributed along the weld width. The magnetic field strength under one roller may be too high, leading to excessive accumulation of magnetic powder and creating an undetectable background; while the magnetic field strength under the other roller will be significantly weakened, falling below the minimum sensitivity value required for detection, causing tiny defects in that area to fail to form effective magnetic traces and resulting in missed detections. Furthermore, the effective detection range of ultra-wide welds (such as 40-60mm+) itself places higher demands on the coverage width of the flaw detection equipment. Once the flaw detector deviates excessively, its effective magnetic field area may only cover a portion of the weld, while the other side or the central area of ​​the weld will be completely in the detection blind zone.

[0008] In summary, while traditional roller-type electromagnetic yoke flaw detectors possess the capability for mobile inspection, they fail to effectively utilize the inherent physical characteristic of weld reinforcement to achieve high-precision automatic tracking. When applied to online inspection of ultra-wide welds in pipelines operating under high pressure and harsh environments, they are prone to technical problems such as misalignment of the weld seam, leading to difficulties in aligning the magnetic field lines perpendicular to the weld defect extension direction and resulting in decreased detection sensitivity. Summary of the Invention

[0009] Given that existing technologies are prone to problems such as misalignment of the weld seam, which can lead to the magnetic field lines being difficult to align with the direction of weld defect extension and a decrease in detection sensitivity, an online inspection device for oil pipeline weld seams based on magnetic particle testing is proposed.

[0010] This application provides an online inspection device for oil pipeline welds based on magnetic particle testing. Its purpose is to actively utilize the "physical track" of the weld reinforcement height for automatic tracking of the flaw detector body, thereby effectively improving the detection sensitivity of the device for welds.

[0011] The technical solution of this invention is as follows: an online inspection device for oil pipeline welds based on magnetic particle testing, comprising a flaw detector body with an internal electromagnetic yoke device for generating a magnetic field, and contact rollers rotatably mounted on the bottom of the flaw detector body's support legs. An installation groove is formed on the bottom surface of the flaw detector body, a fixing rod is fixedly mounted on the inner wall of the installation groove, a telescopic rod is elastically mounted on the wall of the fixing rod, a sealing cylinder is fixedly mounted on the bottom surface of the telescopic rod, and two guide wheels for locating the weld are provided at the bottom of the sealing cylinder. Elastic contact plates are fixedly mounted on the opposite surfaces of the two guide wheels. A pressure regulating component is provided inside the installation groove. During weld inspection, when relative sliding occurs between the flaw detector body and the telescopic rod, the pressure regulating component increases the pressure between the guide wheels and the pipeline wall and weld surface.

[0012] Furthermore, a movable rod is slidably arranged inside the sealing cylinder, a piston is fixedly mounted at the top of the movable rod, and a connecting cylinder with a partition is fixedly mounted at the bottom of the movable rod. A channel is opened inside the movable rod to connect the sealing cylinder and the connecting cylinder. Two T-shaped rods are slidably arranged inside the connecting cylinder, and the outer wall of the vertical circular plate of the T-shaped rod slides against the inner wall of the connecting cylinder. The opposite ends of the horizontal rods of the two T-shaped rods are respectively connected to two guide wheels. A screw is rotatably mounted on the top surface of the piston, and the top of the screw passes through the top surface of the telescopic rod. The screw and the telescopic rod are threaded together.

[0013] Furthermore, a supporting inner cylinder is fixedly installed on the inner wall of the guide wheel, a first locking block is fixedly installed on the inner wall of the supporting inner cylinder, a connecting plate is slidably installed inside the supporting inner cylinder, a second locking block is fixedly installed on the side of the connecting plate near the first locking block, a damping element is installed between the guide wheel and the connecting plate, and the side of the connecting plate near the first locking block is rotatably connected to the end of the transverse rod of the T-shaped rod, and a through hole is opened on the outer wall of the elastic contact plate for the T-shaped rod to pass through.

[0014] Furthermore, the vertical cross-section of the guide wheel on the side away from the connecting cylinder is a narrow-mouthed convex frustum, and the vertical cross-section of the elastic contact plate on the side closer to the connecting cylinder is also a narrow-mouthed convex frustum.

[0015] Furthermore, the damping component is a damping spring.

[0016] Furthermore, the outer wall of the guide wheel is provided with a trumpet-shaped air hole, the top of the trumpet-shaped air hole is provided with an air passage, and the air passage penetrates the side of the guide wheel away from the connecting cylinder. In addition, there are multiple trumpet-shaped air holes, which are evenly distributed on the outer wall of the guide wheel.

[0017] Furthermore, the telescopic rod includes a hinge plate sleeved on the wall of the fixed rod, a sliding plate slidably disposed on the outer wall of the hinge plate, a first threaded hole opened on the top surface of the hinge plate, a second threaded hole opened on the top surface of the sliding plate, and fasteners connecting the hinge plate and the sliding plate, wherein the bottom surface of the sliding plate is fixedly connected to the top surface of the sealing cylinder.

[0018] Furthermore, a ring is fitted on the wall of the fixing rod, and the ring is connected to the hinge plate by a torsion spring. The outer wall of the ring is connected to the inner wall of the mounting groove by a return spring.

[0019] Furthermore, the pressure regulating assembly includes a steering rod fixedly mounted on the outer wall of the ring, a fixing plate fixedly mounted on the inner wall of the mounting groove, and a steering groove opened on the outer wall of the fixing plate for the steering rod to slide. The steering groove is a V-shape with a large bottom space, and the inner diameter of its two inclined sections gradually decreases. In the initial state, the steering rod is located at the bottom of the steering groove.

[0020] Furthermore, a light is provided on the bottom surface of the flaw detector body, and a handle is provided on the top surface of the flaw detector body.

[0021] The beneficial effects of this invention are:

[0022] By using guide wheels and elastic contact plates elastically mounted on the bottom of the flaw detector body, elastic buffering with the pipe surface and dynamic positioning with the weld are achieved, ensuring that the elastic contact plate fits against both sides of the weld during inspection, significantly improving weld tracking accuracy. Furthermore, the design of the elastic contact plate and damping spring allows the equipment to adapt to variations in weld width and irregular surfaces. The narrow-mouthed, protruding frustum-shaped structure of the guide wheels and elastic contact plate further enhances the fit with the weld edge, thereby improving overall inspection sensitivity and operational efficiency. It is particularly suitable for online inspection of curved pipes, reducing the frequency of manual intervention. When applied to online inspection of ultra-wide welds in high-pressure, harsh environment pipelines, it effectively solves the technical problem of traditional roller-type electromagnetic yoke flaw detectors, where misalignment of the weld leads to difficulties in aligning the magnetic field lines perpendicular to the weld defect extension direction.

[0023] By using the pressure regulating components (including the steering rod, the fixed plate, and the steering groove), the torque force of the torsion spring can be increased when the flaw detector body and the telescopic rod slide relative to each other. This increases the contact pressure between the guide wheel, the elastic contact plate, and the surface of the pipe and weld, enhancing contact stability and further effectively reducing the problem of uneven magnetic field distribution caused by the equipment deviating from the weld center. Attached Figure Description

[0024] Figure 1 This is a three-dimensional view of the flaw detector body in the existing technology;

[0025] Figure 2 This is a schematic diagram showing the location of weld reinforcement in the prior art;

[0026] Figure 3 This is an overall perspective view of the present invention;

[0027] Figure 4 This is a schematic diagram showing the state of the pipe weld being held by two guide wheels in this invention;

[0028] Figure 5 This is a schematic diagram of the installation of the fixing plate in this invention;

[0029] Figure 6 This is a schematic diagram of the interior of the sealing cylinder in this invention;

[0030] Figure 7 For the present invention Figure 6 Enlarged view of point A in the middle;

[0031] Figure 8 This is an exploded view of the interior of the guide wheel in this invention;

[0032] Figure 9 This is a schematic diagram of the installation of the ring in this invention;

[0033] Figure 10 This is a schematic diagram of the installation of the steering rod in this invention;

[0034] Figure 11 This is a schematic diagram showing the position between the steering groove and the steering rod in this invention.

[0035] In the picture:

[0036] 1. Flaw detector body; 2. Contact roller; 3. Handle; 4. Lighting lamp; 5. Mounting slot; 6. Telescopic rod; 7. Sealing cylinder; 8. Movable rod; 9. Connecting cylinder; 10. Guide wheel; 11. Piston; 12. Channel; 13. Screw; 14. T-shaped rod; 15. Support inner cylinder; 16. First locking block; 17. Connecting plate; 18. Second locking block; 19. Elastic contact plate; 20. Damping spring; 21. Horn-shaped air hole; 22. Air passage; 23. Fixing rod; 24. Ring; 25. Torsion spring; 26. Return spring; 27. Steering rod; 28. Fixing plate; 29. ​​Steering groove; 30. Hinge plate; 31. Sliding plate; 32. First threaded hole; 33. Second threaded hole; 34. Fastener; 35. Through hole. Detailed Implementation

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0038] Example 1, referring to Figures 3-11This invention provides a first embodiment of an online inspection device for oil pipeline welds based on magnetic particle testing. The device includes a flaw detector body 1 with an internal electromagnetic yoke for generating a magnetic field, and contact rollers 2 rotatably mounted on the bottom of the flaw detector body 1's support legs. The bottom surface of the flaw detector body 1 has an installation groove 5. A fixing rod 23 is fixedly connected to the inner wall of the installation groove 5. A telescopic rod 6 is elastically mounted on the wall of the fixing rod 23. A sealing cylinder 7 is fixedly mounted on the bottom surface of the telescopic rod 6. Two guide wheels 10 for locating the weld are provided at the bottom of the sealing cylinder 7. Elastic contact plates 19 are fixedly connected to the opposite surfaces of the two guide wheels 10. A pressure regulating component is provided inside the installation groove 5. During weld inspection, when relative sliding occurs between the flaw detector body 1 and the telescopic rod 6, the pressure regulating component increases the pressure between the guide wheels 10 and the pipeline wall and weld surface. A lighting lamp 4 is provided on the bottom surface of the flaw detector body 1, and a handle 3 is fixedly mounted on the top surface of the flaw detector body 1.

[0039] Specifically, the telescopic rod 6 and two guide wheels 10, elastically installed at the bottom of the flaw detector body 1, achieve elastic buffering and dynamic positioning between the flaw detector body 1 and the pipe surface. This ensures that the two guide wheels 10 can fit against both sides of the weld during weld inspection, thereby improving weld tracking accuracy. Simultaneously, the pressure regulating component inside the mounting groove 5 increases the pressure between the guide wheels 10 and the pipe wall and weld surface when relative sliding occurs between the flaw detector body 1 and the telescopic rod 6 during inspection. This enhances the contact stability of the guide wheels 10, effectively reducing the flaw detector's deviation from the weld center and the uneven distribution of the magnetic field along the weld width during magnetic particle inspection. This improves overall inspection reliability and operational efficiency, making it particularly suitable for online inspection of curved pipes and reducing the frequency of manual intervention.

[0040] When ambient light is insufficient, the lighting lamp 4 provides a white light / ultraviolet light source to assist in the observation of fluorescent magnetic particles, ensuring real-time identification of weld defects. It is suitable for low-light oil pipeline sites. The handle 3 is ergonomically designed to reduce operator fatigue and improve handheld stability.

[0041] Reference Figure 6 Inside the sealing cylinder 7, a movable rod 8 is slidably installed. A piston 11 is fixedly installed at the top of the movable rod 8, and a connecting cylinder 9 with a partition is fixedly installed at the bottom of the movable rod 8. A channel 12 is opened inside the movable rod 8, through which the sealing cylinder 7 and the connecting cylinder 9 are interconnected. Inside the connecting cylinder 9, two T-shaped rods 14 are slidably installed, and the outer wall of the vertical circular plate of the T-shaped rod 14 slides against the inner wall of the connecting cylinder 9. The opposite ends of the horizontal rods of the two T-shaped rods 14 are respectively connected to two guide wheels 10. A screw 13 is rotatably installed on the top surface of the piston 11, and the top of the screw 13 passes through the top surface of the telescopic rod 6. The screw 13 and the telescopic rod 6 are threadedly connected.

[0042] Specifically, hydraulic oil is filled between the sealing cylinder 7 and the connecting cylinder 9. By rotating the screw 13, the piston 11 is driven to rise, and the hydraulic oil above the piston 11 is pressed into the connecting cylinder 9 through the channel 12. The hydraulic oil pushes the two guide wheels 10 away from each other until the two elastic contact plates 19 can be locked on both sides of the weld and contact the side of the weld reinforcement. When the flaw detector body 1 slides along the outer wall of the pipe, the two elastic contact plates 19 slide and track along the weld trajectory, effectively ensuring the accuracy of the magnetic particle flaw detection range.

[0043] Reference Figures 7-8 A supporting inner cylinder 15 is fixedly installed on the inner wall of the guide wheel 10. A first locking block 16 is fixedly installed on the inner wall of the supporting inner cylinder 15. A connecting plate 17 is slidably installed inside the supporting inner cylinder 15. A second locking block 18 is fixedly installed on the side of the connecting plate 17 near the first locking block 16. A damping element is provided between the guide wheel 10 and the connecting plate 17. The side of the connecting plate 17 near the first locking block 16 is rotatably connected to the end of the transverse rod of the T-shaped rod 14. A through hole 35 is provided on the outer wall of the elastic contact plate 19 for the T-shaped rod 14 to pass through. The damping element is a damping spring 20.

[0044] Specifically, the first locking block 16 and the second locking block 18 limit the sliding range of the connecting plate 17 to prevent derailment caused by excessive offset. The damping spring 20 provides progressive resistance. First, when the weld width changes slightly, the damping spring 20 provides damping force, allowing the guide wheel 10 and the elastic contact plate 19 to slide within a small range, actively adapting to changes in the weld width. Second, when the guide wheel 10 and the elastic contact plate 19 encounter impacts caused by uneven welds, the guide wheel 10 and the elastic contact plate 19 are made of polyurethane (PU), which has high elasticity and is non-magnetic, and can adapt to the irregular surface of the weld, enhancing the fit.

[0045] It should be noted that the T-shaped rod 14 is flexibly connected to the elastic contact plate 19 through the through hole 35, ensuring that the guide wheel 10 maintains low friction when sliding, thereby improving tracking stability, enhancing the overall adaptability of the equipment on tortuous welds, and reducing operator fatigue.

[0046] Reference Figures 6-8 The guide wheel 10 has a narrow-mouthed, convex frustum-shaped vertical section on the side away from the connecting cylinder 9, and the elastic contact plate 19 has a narrow-mouthed, convex frustum-shaped vertical section on the side close to the connecting cylinder 9.

[0047] Specifically, the narrow-mouth protruding frustum design of the guide wheel 10 and the elastic contact plate 19 enhances the fit between the guide wheel 10 and the elastic contact plate 19 and the weld edge. The narrow mouth (opening angle 15-30°) allows the wheel to self-lock in the weld groove, improving positioning accuracy.

[0048] Reference Figure 10The telescopic rod 6 includes a hinge plate 30 sleeved on the wall of the fixed rod 23, a sliding plate 31 slidably installed on the outer wall of the hinge plate 30, a first threaded hole 32 opened on the top surface of the hinge plate 30, a second threaded hole 33 opened on the top surface of the sliding plate 31, and a fastener 34 connecting the hinge plate 30 and the sliding plate 31. The bottom surface of the sliding plate 31 is fixedly connected to the top surface of the sealing cylinder 7, and the fastener 34 is a bolt and a nut.

[0049] Specifically, the sliding between the sliding plate 31 and the hinge plate 30 allows for length adjustment of the telescopic rod 6 via the first threaded hole 32 and the second threaded hole 33. The fastener 34 provides quick assembly and disassembly, thereby enabling it to adapt to pipes of different diameters and improving the applicability of the device.

[0050] Reference Figures 9-11 A ring 24 is fitted on the wall of the fixed rod 23. The ring 24 is connected to the hinge plate 30 by a torsion spring 25. The outer wall of the ring 24 is connected to the inner wall of the mounting groove 5 by a return spring 26.

[0051] Specifically, the torsion spring 25 provides a spring force to the hinge plate 30 to rotate towards the pipe, so that the guide wheel 10 and the elastic contact plate 19 can remain in close contact with the pipe and weld throughout the inspection process. In the initial state, the reset spring 26 fixes the position of the hinge plate 30. During the inspection process, the reset spring 26 allows relative sliding between the flaw detector body 1 and the hinge plate 30 within a certain range.

[0052] Reference Figures 10-11 The pressure regulating assembly includes a steering rod 27 fixedly installed on the outer wall of the ring 24, a fixing plate 28 fixedly installed on the inner wall of the mounting groove 5, and a steering groove 29 opened on the outer wall of the fixing plate 28 for the steering rod 27 to slide. The steering groove 29 is a V-shaped groove with a large bottom space, and the inner diameter of its two inclined sections gradually decreases. In the initial state, the steering rod 27 is located at the bottom of the steering groove 29.

[0053] Specifically, through the V-shaped guide design of the steering groove 29, during the inspection process, when relative sliding occurs between the flaw detector body 1 and the ring 24 due to external vibration or operator hand misoperation, the position of the ring 24 is not easily changed under the tracking and positioning of the guide wheel 10, the elastic contact plate 19 and the weld. Therefore, the flaw detector body 1 will compress the return spring 26, and the fixing plate 28 will move synchronously with the flaw detector body 1. Then, under the action of the steering groove 29, the steering rod 27 moves along the inclined section of the steering groove 29. The inclined section of the steering groove 29 gradually applies pressure to the steering rod 27, realizing dynamic self-locking of the flaw detector body 1 and preventing the position of the flaw detector body 1 from continuing to deviate. Finally, under the elastic force of the return spring 26, the trajectory of the flaw detector body 1 is pushed back to its original position.

[0054] Example 2, refer to Figures 6-7 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that: the outer wall of the guide wheel 10 is provided with a trumpet-shaped air hole 21, the top of the trumpet-shaped air hole 21 is provided with an air passage 22, and the air passage 22 penetrates the side of the guide wheel 10 away from the connecting cylinder 9, and multiple trumpet-shaped air holes 21 are provided, and multiple trumpet-shaped air holes 21 are evenly distributed on the outer wall of the guide wheel 10.

[0055] Specifically, during the movement of the guide wheel 10, a local negative pressure zone is easily formed at the flared air hole 21, which to a certain extent increases the adsorption force between the guide wheel 10 and the pipe and weld surfaces, further reducing the risk of the equipment shifting due to vibration or changes in pipe curvature. Furthermore, since the air passage 22 is connected to the external environment, it facilitates the separation of the flared air hole 21 from the pipe and weld surfaces, without affecting the normal movement and rotation of the guide wheel 10.

[0056] In addition, an external air pump and a vent pipe can be connected to the side of the guide wheel 10 away from the connecting cylinder 9. The external air pump blows air into the air passage 22, and the gas is blown out from the trumpet-shaped air hole 21, which can clean impurities on the surface of the pipe and weld before magnetic particle inspection.

[0057] The remaining structure is the same as that in Example 1.

[0058] Working principle:

[0059] First, the operator rotates screw 13, causing piston 11 to rise. Hydraulic oil above piston 11 is then forced into connecting cylinder 9 through channel 12. The hydraulic oil pushes two guide wheels 10 away from each other until two elastic contact plates 19 are engaged on both sides of the weld and contact the side of the weld reinforcement. Then, the operator places the flaw detector body 1 entirely on the pipe wall. When ambient light is insufficient, illumination lamp 4 provides white / ultraviolet light to assist magnetic particle observation, ensuring real-time identification of weld defects.

[0060] The operator holds a spray bottle filled with magnetic particle testing fluid in one hand and moves the flaw detector body 1 along the pipe wall at the center of the weld with the other. During the inspection, under the tracking action of the two guide wheels 10 and the elastic contact plate 19, the center line connecting the two contact rollers 2 on both sides of the flaw detector body 1 basically coincides with the center of the weld. Then, the magnetic particle testing fluid is sprayed onto the local inspection area between the two contact rollers 2. When a defect exists in the weld in this area, the magnetic lines of force are distorted, forming a leakage magnetic field, which attracts magnetic particles and forms visible magnetic traces, thereby locating the defect. After the inspection and observation of this area is completed, the flaw detector body 1 is moved to the next inspection area until the weld inspection of the entire pipeline is completed.

[0061] It should be noted that during the inspection process, if relative sliding occurs between the flaw detector body 1 and the ring 24 due to external vibration or operator error, the pressure regulating component can increase the torque force of the torsion spring 25, increase the contact pressure between the guide wheel 10, the elastic contact plate 19 and the surface of the pipe and weld, enhance contact stability, and effectively reduce the problem of uneven magnetic field distribution caused by the equipment deviating from the weld center. At the same time, the inclined section of the steering groove 29 gradually applies pressure to the steering rod 27, realizing dynamic self-locking of the flaw detector body 1 and preventing the position of the flaw detector body 1 from continuing to deviate. Finally, under the elastic force of the return spring 26, the trajectory of the flaw detector body 1 is pushed back to its original position.

[0062] 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 magnetic particle inspection based on-line oil pipeline weld detection device, comprising an inspection instrument body (1) with an electromagnetic yoke device for generating a magnetic field inside, and a contact roller (2) rotatably arranged at the bottom of the inspection instrument body (1) foot, characterized in that: The bottom surface of the flaw detector body (1) is provided with a mounting groove (5), the inner wall of the mounting groove (5) is fixedly provided with a fixed rod (23), the rod wall of the fixed rod (23) is elastically provided with a telescopic rod (6), the bottom surface of the telescopic rod (6) is fixedly provided with a sealing cylinder (7), the bottom of the sealing cylinder (7) is provided with two guide wheels (10) for positioning the weld, and the opposite surfaces of the two guide wheels (10) are fixedly provided with elastic touch plates (19). The inside of the mounting groove (5) is provided with a pressure adjusting assembly, when the flaw detector body (1) and the telescopic rod (6) slide relative to each other during the weld detection process, the pressure adjusting assembly increases the pressure between the guide wheels (10) and the pipe wall and the weld surface. The inside of the sealing cylinder (7) is slidably provided with a movable rod (8), the top end of the movable rod (8) is fixedly provided with a piston (11), the bottom end of the movable rod (8) is fixedly provided with a connecting cylinder (9) with a partition plate, the inside of the movable rod (8) is provided with a channel (12), the sealing cylinder (7) and the connecting cylinder (9) are communicated with each other through the channel (12), the inside of the connecting cylinder (9) is slidably provided with two T-shaped rods (14), the vertical plate outer wall of the T-shaped rod (14) is slidably attached to the inner wall of the connecting cylinder (9), and the opposite ends of the horizontal rods of the two T-shaped rods (14) are respectively connected with the two guide wheels (10). The top surface of the piston (11) is rotatably provided with a screw rod (13), the top end of the screw rod (13) penetrates through the top surface of the telescopic rod (6), and the screw rod (13) is threadedly connected with the telescopic rod (6). The inner wall of the guide wheel (10) is fixedly provided with a supporting inner cylinder (15), the inner wall of the supporting inner cylinder (15) is fixedly provided with a first clamping block (16), the inside of the supporting inner cylinder (15) is slidably provided with a connecting plate (17), the side surface of the connecting plate (17) close to the first clamping block (16) is fixedly provided with a second clamping block (18), a damping member is arranged between the guide wheel (10) and the connecting plate (17), the side surface of the connecting plate (17) close to the first clamping block (16) is rotatably connected with the end portion of the horizontal rod of the T-shaped rod (14), and the outer wall of the elastic touch plate (19) is provided with a through hole (35) for the T-shaped rod (14) to pass through. The side vertical section of the guide wheel (10) away from the connecting cylinder (9) is a narrow-mouthed convex circular truncated cone, and the side vertical section of the elastic touch plate (19) close to the connecting cylinder (9) is a narrow-mouthed convex circular truncated cone.

2. The magnetic particle inspection based on-line oil pipeline weld inspection apparatus according to claim 1, characterized in that: The damping member is a damping spring (20).

3. The magnetic particle inspection based on-line oil pipeline weld inspection apparatus according to claim 1, characterized in that: The outer wall of the guide wheel (10) is provided with a horn-shaped air hole (21), the top of the horn-shaped air hole (21) is provided with an air channel (22), the air channel (22) penetrates through the side surface of the guide wheel (10) away from the connecting cylinder (9), and a plurality of horn-shaped air holes (21) are arranged on the outer wall of the guide wheel (10).

4. The magnetic particle inspection based on-line oil pipeline weld inspection apparatus according to claim 1, characterized in that: The telescopic rod (6) comprises a hinged plate (30) sleeved on the rod wall of the fixed rod (23), a sliding plate (31) slidingly arranged on the outer wall of the hinged plate (30), a first threaded hole (32) formed on the top surface of the hinged plate (30), a second threaded hole (33) formed on the top surface of the sliding plate (31), and a fastener (34) connecting the hinged plate (30) and the sliding plate (31), and the bottom surface of the sliding plate (31) is fixedly connected with the top surface of the sealing cylinder (7).

5. The magnetic particle inspection based on-line oil pipeline weld inspection apparatus according to claim 4, characterized in that: The rod wall of the fixed rod (23) is sleeved with a circular ring (24), the circular ring (24) and the hinged plate (30) are connected through a torsion spring (25), and the outer wall of the circular ring (24) and the inner wall of the mounting groove (5) are connected through a reset spring (26).

6. The magnetic particle inspection based on-line oil pipeline weld inspection apparatus according to claim 5, characterized in that: The pressure adjusting assembly comprises a steering rod (27) fixedly arranged on the outer wall of the circular ring (24), a fixed plate (28) fixedly arranged on the inner wall of the mounting groove (5), and a steering groove (29) formed on the outer wall of the fixed plate (28) for the sliding of the steering rod (27), and the steering groove (29) is a V-shaped groove with a large bottom space, the inner diameters of the two inclined sections gradually decrease, and the steering rod (27) is located at the bottom of the steering groove (29) in the initial state.

7. The magnetic particle inspection based on-line oil pipeline weld inspection apparatus according to claim 1, characterized in that: The bottom surface of the flaw detector body (1) is provided with an illuminating lamp (4), and the top surface of the flaw detector body (1) is provided with a handle (3).

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