An external magnetic flux leakage detection device for subsea pipelines and its detection method

Abstract

The present invention discloses a magnetic flux leakage detection device for submarine pipelines and its detection method, which relates to the field of magnetic flux leakage detection of pipelines. In order to solve the problem that there is no mechanism for detecting and adjusting the relative position between the detection device and the submarine pipeline, when the center line of the detection device is not collinear with the center line of the submarine pipeline, there are data deviations in the magnetic flux leakage detection of the arc-shaped weld or quasi-spiral weld in the same vertical plane, which affects the efficiency of magnetic flux leakage detection. On both sides of the outside of the submarine pipeline, a first side detection housing and a second side detection housing are provided. The first side detection housing and the second side detection housing have the same structure. The first side detection housing and the second side detection housing both include an annular housing part. In the middle of the upper end inside the annular housing part, a fourth driving motor is installed through a motor bracket. The output shaft end of the fourth driving motor is installed with a second driving gear through a keyway.

Description

Technical Field

[0001] The present invention relates to the field related to external magnetic flux leakage detection of pipelines, and specifically to an external magnetic flux leakage detection device for submarine pipelines and its detection method. Background Technique

[0002] A submarine pipeline is a pipeline that continuously transports a large amount of oil (gas) under the sea through a sealed pipeline. It is a main component of the offshore oil (gas) field development and production system and is also the fastest, safest, and most economical and reliable offshore oil and gas transportation method.

[0003] Once perforation, cracking, seal failure, etc. occur in the submarine pipeline, it will lead to major accidents such as major fires or explosions caused by oil leakage, posing a serious threat to people's lives and property safety and the ecological environment. Among the accidents of pipeline leakage and explosion, one of the most important risks affecting its safety is weld defects. Therefore, it is necessary to detect the submarine pipeline after production and before putting it into use; thus, accurately and quickly detecting pipeline welds has very important safety significance and economic value.

[0004] A relatively common in-service detection method for pipeline defects is the magnetic flux leakage detection technology. The principle of magnetic flux leakage detection is that when a ferromagnetic steel pipe is fully magnetized, the magnetic force lines in the pipe wall are blocked by defects on its surface or near the surface, and the magnetic force lines at the defect sites are distorted. Part of the magnetic force lines leak out of the inner and outer surfaces of the steel pipe, forming a magnetic flux leakage field. The magnetic flux leakage signal is acquired and sensed by a magnetic sensitive element, and is converted into a defect electrical signal. These signals are processed through filtering, amplification, analog-to-digital conversion, etc., so as to judge the defects.

[0005] When performing external magnetic flux leakage detection, it is necessary to place the detection device outside the submarine pipeline. Currently, after the detection device is located outside the submarine pipeline, detection can be directly carried out. When the weld is arc-shaped, it is necessary to drive the detection device to rotate for magnetic flux leakage detection, but there is no mechanism for detecting and adjusting the relative position between the detection device and the submarine pipeline. When the center line of the detection device and the center line of the submarine pipeline are not collinear, there are data deviation situations in the magnetic flux leakage detection of arc-shaped welds or quasi-helical welds in the same vertical plane, affecting the magnetic flux leakage detection efficiency. Summary of the Invention

[0006] The purpose of the present invention is to provide an external magnetic flux leakage detection device for submarine pipelines and its detection method to solve the problem proposed in the above background technique that there is currently no mechanism for detecting and adjusting the relative position between the detection device and the submarine pipeline. When the center line of the detection device and the center line of the submarine pipeline are not collinear, there are data deviation situations in the magnetic flux leakage detection of arc-shaped welds or quasi-helical welds in the same vertical plane, affecting the magnetic flux leakage detection efficiency.

[0007] To achieve the above object, the present invention provides the following technical solution: An external magnetic leakage detection device for a subsea pipeline, including a subsea pipeline, on both sides of the outside of the subsea pipeline, a first side detection housing and a second side detection housing are provided. The first side detection housing and the second side detection housing have the same structure. The first side detection housing and the second side detection housing both include an annular housing portion. In the middle of the upper end inside the annular housing portion, a fourth driving motor is installed through a motor bracket. At the output shaft end of the fourth driving motor, a second driving gear is installed through a keyway. On the outer side inside the annular housing portion, a center offset detection driving component is provided. The center offset detection driving component includes a fixed ring and a rotating ring. The fixed ring is fixedly welded to the annular housing portion. The rotating ring includes an upper half ring. On the outer side of the upper half ring close to the second driving gear, a lower outer ring is integrally connected. On the inner side of the upper half ring close to the second driving gear, a lower inner ring is integrally connected. An annular channel is formed between the upper half ring, the lower outer ring and the lower inner ring. The second driving gear is located in the annular channel. The diameter of the second driving gear is smaller than the ring diameter of the annular channel. On the inner side surface of the lower outer ring, an annular tooth portion is provided. The annular tooth portion meshes with the second driving gear. At both ends of the other side of the upper half ring, driving grooves are provided. The driving grooves are inclined. At the position corresponding to the driving grooves on the fixed ring, sliding grooves are provided. In the middle of the inner side of the sliding grooves, limiting grooves are provided. A sliding column is slidably connected in the sliding grooves. The width of the sliding grooves is the same as the diameter of the sliding column. One end of the sliding column extends into the driving grooves. The width of the driving grooves is the same as the diameter of the sliding column. At the position corresponding to the limiting grooves on the outer side of the sliding column, a limiting ring is provided. The width of the limiting grooves is the same as the outer diameter of the limiting ring. The limiting ring is fixed to the sliding column. On the side of the sliding column away from the rotating ring, a center offset detection moving component is provided. The center offset detection moving component includes an L-shaped fixed column. The L-shaped fixed column is fixed to the sliding column. At both ends of the inner side of the L-shaped fixed column, fixed side plates are integrally connected. Between each group of two fixed side plates, inner rolling wheels are rotatably connected through shafts. The inner rolling wheels are in contact with the subsea pipeline. The center offset detection moving component further includes a pressure sensor.

[0008] Preferably, a first lower driving and adjusting unit is provided at the lower end of the outside of the first side detection housing, and a second lower driving and adjusting unit is provided at the lower end of the outside of the second side detection housing. The first lower driving and adjusting unit and the second lower driving and adjusting unit have the same structure.

[0009] Preferably, both the first lower drive adjustment unit and the second lower drive adjustment unit include a fixed pier and a lower fixed plate. The fixed pier is located at the upper end of the lower fixed plate. The fixed pier is fixedly welded to the first side detection housing or the second side detection housing. At the front and rear ends of the upper end of the lower fixed plate, fixed bearing seats are fixedly welded. At the rear end of the rear fixed bearing seat, a first drive motor is installed. Between the two fixed bearing seats, a bidirectional screw is installed along the output shaft end of the first drive motor. At the front and rear ends of the outside of the bidirectional screw, threaded sliding blocks are provided. The threaded sliding blocks are threadedly connected to the bidirectional screw and are limitedly slidably connected to the lower fixed plate. On the threaded sliding block, a height adjustment rotating rod is rotatably connected by a shaft. The other end of the height adjustment rotating rod is rotatably connected by a shaft to a first rotating seat, and the first rotating seat is fixedly welded to the fixed pier.

[0010] Preferably, in the middle of the lower end of the lower fixed plate, a fixed vertical plate is fixedly connected. Inside the fixed vertical plate, a second drive motor is installed. On the other side of the fixed vertical plate, along the output shaft end of the second drive motor, a drive worm gear is installed. At the lower end of the drive worm gear, a driven worm is meshed and connected. At both ends of the driven worm, connecting shafts are integrally connected. At both ends of the lower end of the lower fixed plate, installation vertical plates are provided. Between each group of two installation vertical plates, a lower drive wheel is installed. The other end of the connecting shaft passes through the inner installation vertical plate and is connected to the lower drive wheel.

[0011] Preferably, in the middle of the outside of the subsea pipeline, an intermediate detection housing is provided. On both sides of the intermediate detection housing, side sealing rings are fixedly connected. The inner sides of the first side detection housing and the second side detection housing both extend into the interior of the intermediate detection housing. The side sealing rings are rotatably connected to the first side detection housing and the second side detection housing through ball bearings. Inside the intermediate detection housing, on both sides, intermediate fixing rings are fixedly connected. On the inner surface of the intermediate fixing ring, a connecting tooth part is provided. Inside the first side detection housing and the second side detection housing, at the upper end of the inner side, a third drive motor is installed through a motor bracket. At the output shaft end of the third drive motor, a first drive gear is installed. The first drive gear is meshed with the connecting tooth part.

[0012] Preferably, inside the intermediate detection housing, along the outside between the two intermediate fixing rings, a connecting plate is provided. At one end of the connecting plate close to the subsea pipeline, a yoke iron is installed. On one side of the other end of the yoke iron, an N-pole permanent magnet is installed. In the middle of the other end of the yoke iron, a Hall sensor is installed. On the other side of the other end of the yoke iron, an S-pole permanent magnet is installed. On both sides between the connecting plate and the inner wall of the intermediate detection housing, spring rods are provided. Both ends of the spring rods are rotatably connected to the connecting plate and the inner wall of the intermediate detection housing through second rotating seats.

[0013] Preferably, the first-side detection housing and the second-side detection housing further include a horn-shaped housing portion, which is welded and fixed to the outside of the annular housing portion. A circular groove is formed in the middle of the outer side surface of the horn-shaped housing portion, and the diameter of the circular groove is larger than the diameter of the subsea pipeline.

[0014] A detection method includes the following steps:

[0015] Step 1: Lift the middle of the subsea pipeline to move this detection device to the outside of the subsea pipeline, cancel the middle lift, and clamp and fix both ends of the subsea pipeline.

[0016] Step 2: The fourth driving motor drives the second driving gear to rotate. The rotation of the second driving gear drives the rotation ring to rotate through the meshing relationship with the annular tooth portions of the upper and lower half outer rings of the rotation ring. Under the action of the rotation of the rotation ring, the driving groove drives the sliding column to slide along the sliding groove on the fixed ring, and the inner rolling wheels on the center-offset detection moving assembly contact the subsea pipeline.

[0017] Step 3: When the pressure sensor values in the upper two center-offset detection moving assemblies are the same, and the pressure sensor values in the lower two center-offset detection moving assemblies are the same, but the pressure sensor values in the upper two center-offset detection moving assemblies are different from the pressure sensor values in the lower two center-offset detection moving assemblies, it indicates that the center line of the magnetic flux leakage detection device and the center line of the subsea pipeline are not collinear. However, at this time, both the magnetic flux leakage detection device and the subsea pipeline are set horizontally. Synchronously adjust the heights of the first lower driving adjustment unit and the second lower driving adjustment unit and the clamping mechanisms at both ends of the subsea pipeline until the pressure sensor values of the four are the same.

[0018] Step 4: When the pressure sensor values in the upper two center-offset detection moving assemblies are different, and the pressure sensor values in the lower two center-offset detection moving assemblies are different, it indicates that the center line of the magnetic flux leakage detection device and the center line of the subsea pipeline are not collinear, and at least one of the magnetic flux leakage detection device and the subsea pipeline is not set horizontally. Adjust the heights of the first lower driving adjustment unit, the second lower driving adjustment unit, and the clamping mechanisms at both ends of the subsea pipeline respectively until the pressure sensor values of the four are the same.

[0019] Step 5: In Steps 3 and 4, when adjusting the heights of the first lower driving adjustment unit and the second lower driving adjustment unit, the first driving motor drives the bidirectional screw to rotate, driving the threaded sliding blocks to move synchronously towards the middle or synchronously towards both ends, and driving the fixed pier to lift or lower through the rotation relationship of the height-adjusting rotating rod.

[0020] Step 6: The second driving motor drives the driving worm gear to rotate. The rotation of the driving worm gear drives the driven worm to rotate through the meshing relationship with the driven worm. The driven worm drives the lower driving wheel to rotate through the connecting shaft, realizing the movement of this device outside the subsea pipeline until it moves to the weld position.

[0021] Step 7: When the weld is horizontal, the second driving motor drives the lower driving wheel to rotate to achieve horizontal movement and uses a Hall sensor for magnetic flux leakage detection; when the weld is an arc on a vertical plane, the third driving motor drives the first driving gear to rotate, and drives the middle fixed ring to move through the meshing relationship between the first driving gear and the connecting tooth part on the middle fixed ring. The middle detection housing is driven to rotate, and a Hall sensor is used for magnetic flux leakage detection; when the weld is a quasi-spiral weld, the second driving motor and the third driving motor jointly drive and cooperate to achieve driving movement along the weld path.

[0022] Step 8: In Step 7, when performing magnetic flux leakage detection, the yoke iron, N-pole permanent magnet, and S-pole permanent magnet are driven and cooperated to fully magnetize the pipe wall of the subsea pipeline to form a closed magnetic field. When reaching the defect position of the pipe wall, the magnetic resistance at the defect and its vicinity increases, causing the magnetic field near the defect to distort and generating magnetic flux leakage, which is sensed by the Hall sensor to detect the defect position of the pipe wall.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. In this invention, the fourth driving motor drives the second driving gear to rotate, and drives the rotating ring to rotate through the meshing relationship between the second driving gear and the annular tooth parts of the upper and lower half outer rings of the rotating ring. Under the action of the rotation of the rotating ring, the driving groove drives the sliding column to slide along the sliding groove on the fixed ring, and the inner rolling wheel on the center offset detection and moving assembly contacts the subsea pipeline. When the pressure sensor values in the upper two center offset detection and moving assemblies are the same, and the pressure sensor values in the lower two center offset detection and moving assemblies are the same, but the pressure sensor values in the upper two center offset detection and moving assemblies are different from the pressure sensor values in the lower two center offset detection and moving assemblies, it indicates that the center line of the magnetic flux leakage detection device and the center line of the subsea pipeline are not collinear, but at this time both the magnetic flux leakage detection device and the subsea pipeline are set horizontally; when the pressure sensor values in the upper two center offset detection and moving assemblies are different, and the pressure sensor values in the lower two center offset detection and moving assemblies are also different, it indicates that the center line of the magnetic flux leakage detection device and the center line of the subsea pipeline are not collinear, and at least one of the magnetic flux leakage detection device and the subsea pipeline is not set horizontally. By judging the relative position relationship between the detection device and the subsea pipeline through the pressure sensor values in the four center offset detection and moving assemblies, subsequent adjustment can be carried out, and the magnetic flux leakage detection for arc-shaped welds is more accurate later, solving the problem that there is currently no mechanism for detecting and adjusting the relative position between the detection device and the subsea pipeline. When the center line of the detection device and the center line of the subsea pipeline are not collinear, there are data deviations in the magnetic flux leakage detection for arc-shaped welds or quasi-spiral welds on the same vertical plane, affecting the magnetic flux leakage detection efficiency.

[0025] 2. In the present invention, the first driving motor drives the bidirectional screw to rotate, driving the threaded sliding blocks to move synchronously towards the middle or synchronously towards both ends. Through the rotational relationship of the height-adjusting rotating rod, the fixed pier is jacked up or lowered. When the heights of the first lower driving adjustment unit and the second lower driving adjustment unit can be adjusted, position correction is achieved in cooperation after detecting the relative position, which is beneficial to improving the detection accuracy and avoiding damage to some structures during the movement due to position deviation.

[0026] 3. In the present invention, when the weld seam is horizontal, the second driving motor drives the lower driving wheel to rotate to achieve horizontal movement and uses a Hall sensor for magnetic flux leakage detection; when the weld seam is an arc on a vertical plane, the third driving motor drives the first driving gear to rotate. Through the meshing relationship between the first driving gear and the connecting tooth part on the middle fixed ring, the middle fixed ring is driven to move, and the middle detection housing is driven to rotate, using a Hall sensor for magnetic flux leakage detection; when the weld seam is a spiral-like weld seam, the second driving motor and the third driving motor jointly drive and cooperate to achieve driving movement along the weld seam path; through the setting of each driving structure, magnetic flux leakage detection of weld seams with different specifications and shapes is realized, making the detection versatility of this detection device wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the front view of an external magnetic flux leakage detection device for a submarine pipeline of the present invention;

[0028] Figure 2 is the internal structure schematic diagram of the first side detection housing, the middle detection housing, and the second side detection housing of an external magnetic flux leakage detection device for a submarine pipeline of the present invention;

[0029] Figure 3 is the partial exploded structure schematic diagram of the center offset detection driving assembly of an external magnetic flux leakage detection device for a submarine pipeline of the present invention;

[0030] Figure 4 is the reverse structure schematic diagram of the rotating ring of an external magnetic flux leakage detection device for a submarine pipeline of the present invention;

[0031] Figure 5 is the three-dimensional structure schematic diagram of the center offset detection moving assembly of an external magnetic flux leakage detection device for a submarine pipeline of the present invention;

[0032] Figure 6 is the side view structure schematic diagram of the first lower driving adjustment unit and the second lower driving adjustment unit of an external magnetic flux leakage detection device for a submarine pipeline of the present invention;

[0033] Figure 7 is the exploded structure schematic diagram of the first side detection housing, the middle detection housing, and the second side detection housing of an external magnetic flux leakage detection device for a submarine pipeline of the present invention.

[0034] In the figure: 1, subsea pipeline; 2, first side detection housing; 3, intermediate detection housing; 4, second side detection housing; 5, intermediate fixing ring; 6, connecting tooth part; 7, side sealing ring; 8, ball bearing; 9, annular housing part; 10, flared housing part; 11, circular groove; 12, first lower drive adjustment unit; 13, second lower drive adjustment unit; 14, fixed pier; 15, lower fixing plate; 16, fixed bearing seat; 17, bidirectional screw; 18, first drive motor; 19, threaded sliding block; 20, height adjustment rotating rod; 21, first rotating seat; 22, second drive motor; 23, fixed vertical plate; 24, driving worm gear; 25, driven worm; 26, connecting shaft; 27, mounting vertical plate; 28, lower drive wheel; 29, third drive motor; 30, first drive gear; 31, fourth drive motor; 32, second drive gear; 33, center offset detection drive assembly; 34, center offset detection moving assembly; 35, fixing ring; 36, sliding groove; 37, limiting groove; 38, sliding column; 39, limiting ring; 40, rotating ring; 41, upper half ring; 42, lower outer half ring; 43, lower inner half ring; 44, annular channel; 45, annular tooth part; 46, driving groove; 47, L-shaped fixing column; 48, fixed side plate; 49, inner rolling wheel; 50, connecting plate; 51, yoke; 52, N-pole permanent magnet; 53, Hall sensor; 54, S-pole permanent magnet; 55, spring rod; 56, second rotating seat. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0036] Please refer to Figure 1-7, an embodiment provided by the present invention: a magnetic flux leakage detection device for a subsea pipeline, including a subsea pipeline 1. On both sides outside the subsea pipeline 1, a first side detection housing 2 and a second side detection housing 4 are provided. The first side detection housing 2 and the second side detection housing 4 have the same structure. The first side detection housing 2 and the second side detection housing 4 both include an annular housing portion 9. The first side detection housing 2 and the second side detection housing 4 also include a trumpet-shaped housing portion 10. The trumpet-shaped housing portion 10 is welded and fixed to the outside of the annular housing portion 9. In the middle of the outer side of the trumpet-shaped housing portion 10, a circular groove 11 is opened. The diameter of the circular groove 11 is larger than the diameter of the subsea pipeline 1. In the middle of the upper end inside the annular housing portion 9, a fourth driving motor 31 is installed through a motor bracket. At the output shaft end of the fourth driving motor 31, a second driving gear 32 is installed through a keyway. On the outer side inside the annular housing portion 9, a center offset detection driving component 33 is provided. The center offset detection driving component 33 includes a fixed ring 35 and a rotating ring 40. The fixed ring 35 is welded and fixed to the annular housing portion 9. The rotating ring 40 includes an upper half ring 41. On the outer side of the upper half ring 41 close to the second driving gear 32, a lower half outer ring 42 is integrally connected. On the inner side of the upper half ring 41 close to the second driving gear 32, a lower half inner ring 43 is integrally connected. An annular channel 44 is formed between the upper half ring 41, the lower half outer ring 42, and the lower half inner ring 43. The second driving gear 32 is located in the annular channel 44. The diameter of the second driving gear 32 is smaller than the ring diameter of the annular channel 44. On the inner side surface of the lower half outer ring 42, an annular tooth portion 45 is provided. The annular tooth portion 45 meshes with the second driving gear 32. At both ends of the other side of the upper half ring 41, driving grooves 46 are opened. The driving grooves 46 are inclined. At the corresponding positions on the fixed ring 35 to the driving grooves 46, sliding grooves 36 are provided. In the middle of the inner side of the sliding grooves 36, limiting grooves 37 are opened. In the sliding grooves 36, sliding columns 38 are slidably connected. The width of the sliding grooves 36 is the same as the diameter of the sliding columns 38. One end of the sliding column 38 extends into the driving grooves 46. The width of the driving grooves 46 is the same as the diameter of the sliding columns 38. At the corresponding positions of the sliding columns 38 outside to the limiting grooves 37, limiting rings 39 are provided. The width of the limiting grooves 37 is the same as the outer diameter of the limiting rings 39. The limiting rings 39 are fixed to the sliding columns 38. On the side of the sliding columns 38 away from the rotating ring 40, a center offset detection moving component 34 is provided. The center offset detection moving component 34 includes an L-shaped fixing column 47. The L-shaped fixing column 47 is fixed to the sliding column 38. At both ends of the inner side of the L-shaped fixing column 47, fixing side plates 48 are integrally connected. Between each group of two fixing side plates 48, inner rolling wheels 49 are rotatably connected through shafts. The inner rolling wheels 49 are in contact with the subsea pipeline 1. The center offset detection moving component 34 also includes a pressure sensor. The pressure sensor is blocked in the figure, but since its own installation and connection are not particularly special, no specific description is made here. However, it cooperates with other structures to realize the detection of the relative position between the detection device and the subsea pipeline 1.

[0037] The fourth drive motor 31, the second drive gear 32, and the center offset detection drive assembly 33 are driven and coordinated to achieve the movement of the center offset detection moving assembly 34; if the position of the center offset detection moving assembly 34 is set to be fixed, when the subsea pipeline 1 enters the first-side detection housing 2 and the second-side detection housing 4, it is easy to damage the center offset detection moving assembly 34 due to the deviation of the entry position. Therefore, it is necessary to make the position of the center offset detection moving assembly 34 adjustable; when the detection device is connected to the subsea pipeline 1, it is far away from the subsea pipeline 1 and approaches for position detection after being outside the subsea pipeline 1.

[0038] When the pressure sensor values in the two upper center offset detection moving assemblies 34 are the same, and the pressure sensor values in the two lower center offset detection moving assemblies 34 are the same, but the pressure sensor values in the two upper center offset detection moving assemblies 34 are different from the pressure sensor values in the two lower center offset detection moving assemblies 34, it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline 1, but at this time both the magnetic flux leakage detection device and the subsea pipeline 1 are set horizontally; when the pressure sensor values in the two upper center offset detection moving assemblies 34 are different, and the pressure sensor values in the two lower center offset detection moving assemblies 34 are different, it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline 1, and at least one of the magnetic flux leakage detection device and the subsea pipeline 1 is not set horizontally. The relative position relationship between the detection device and the subsea pipeline 1 is judged by the pressure sensor values in the four center offset detection moving assemblies 34, so that subsequent adjustment can be carried out, and the detection of air leakage in the arc weld will be more accurate during subsequent detection.

[0039] Please refer to Figure 1 and Figure 6, a first lower drive and adjustment unit 12 is provided at the lower end outside the first-side detection housing 2, and a second lower drive and adjustment unit 13 is provided at the lower end outside the second-side detection housing 4. The first lower drive and adjustment unit 12 and the second lower drive and adjustment unit 13 have the same structure. Both the first lower drive and adjustment unit 12 and the second lower drive and adjustment unit 13 include a fixed pier 14 and a lower fixed plate 15. The fixed pier 14 is located at the upper end of the lower fixed plate 15. The fixed pier 14 is fixedly welded to the first-side detection housing 2 or the second-side detection housing 4. At the front and rear ends of the upper end of the lower fixed plate 15, fixed bearing seats 16 are fixedly welded. A first drive motor 18 is installed at the rear end of the rear fixed bearing seat 16. A bidirectional screw 17 is installed between the two fixed bearing seats 16 along the output shaft end of the first drive motor 18. Threaded sliding blocks 19 are provided at the front and rear ends outside the bidirectional screw 17. The threaded sliding blocks 19 are threadedly connected to the bidirectional screw 17. The threaded sliding blocks 19 are in limiting sliding connection with the lower fixed plate 15. A height-adjusting rotating rod 20 is rotatably connected to the threaded sliding block 19 through a shaft. The other end of the height-adjusting rotating rod 20 is rotatably connected to a first rotating seat 21 through a shaft. The first rotating seat 21 is fixedly welded to the fixed pier 14. The first drive motor 18 drives the bidirectional screw 17 to rotate, driving the threaded sliding blocks 19 to move synchronously towards the middle or synchronously towards the two ends. Through the rotation relationship of the height-adjusting rotating rod 20, the fixed pier 14 is jacked up or lowered. When the heights of the first lower drive and adjustment unit 12 and the second lower drive and adjustment unit 13 can be adjusted, position correction can be achieved in cooperation after detecting the relative positions, which is beneficial to improving the detection accuracy and avoiding the situation of partial structural damage during the movement due to position deviation. A fixed vertical plate 23 is fixedly connected to the middle of the lower end of the lower fixed plate 15. A second drive motor 22 is installed inside the fixed vertical plate 23. A driving worm gear 24 is installed on the other side of the fixed vertical plate 23 along the output shaft end of the second drive motor 22. A driven worm 25 is meshed and connected to the lower end of the driving worm gear 24. Connecting shafts 26 are integrally connected to both ends of the driven worm 25. Installation vertical plates 27 are provided at both ends of the lower end of the lower fixed plate 15. A lower drive wheel 28 is installed between each group of two installation vertical plates 27. The other end of the connecting shaft 26 passes through the inner installation vertical plate 27 and is connected to the lower drive wheel 28. The second drive motor 22 drives the driving worm gear 24 to rotate, driving the driven worm 25 to rotate through the meshing relationship between the driving worm gear 24 and the driven worm 25. The driven worm 25 drives the lower drive wheel 28 to rotate through the connecting shaft 26, realizing the movement of the device outside the submarine pipeline 1.

[0040] Please refer to Figure 1 , Figure 2 and Figure 7, an intermediate detection housing 3 is provided in the middle outside the subsea pipeline 1. Side sealing rings 7 are fixedly connected to both sides of the intermediate detection housing 3. The inner sides of the first side detection housing 2 and the second side detection housing 4 both extend into the interior of the intermediate detection housing 3. The side sealing rings 7 are rotatably connected to the first side detection housing 2 and the second side detection housing 4 through ball bearings 8. Intermediate fixing rings 5 are fixedly connected to both sides inside the intermediate detection housing 3. Connecting tooth portions 6 are provided on the inner surface of the intermediate fixing rings 5. Third drive motors 29 are installed at the upper inner sides inside the first side detection housing 2 and the second side detection housing 4 through motor brackets. First drive gears 30 are installed at the output shaft ends of the third drive motors 29. The first drive gears 30 are meshed with the connecting tooth portions 6.

[0041] Please refer to Figure 2 , a connecting plate 50 is provided on the outer side between the two intermediate fixing rings 5 inside the intermediate detection housing 3. An armature 51 is installed at one end of the connecting plate 50 close to the subsea pipeline 1. An N - pole permanent magnet 52 is installed on one side of the other end of the armature 51. A Hall sensor 53 is installed in the middle of the other end of the armature 51. An S - pole permanent magnet 54 is installed on the other side of the other end of the armature 51. By driving and moving to cooperate with the armature 51, the N - pole permanent magnet 52 and the S - pole permanent magnet 54, the pipe wall of the subsea pipeline 1 is fully magnetized to form a closed magnetic field. When reaching the position of the pipe wall defect, the magnetic resistance at the defect and its vicinity increases, causing the magnetic field distortion near the defect and generating leakage magnetic flux, which is sensed by the Hall sensor 53 to detect the position of the pipe wall defect; Spring rods 55 are provided on both sides between the connecting plate 50 and the inner wall of the intermediate detection housing 3. Both ends of the spring rods 55 are rotatably connected to the connecting plate 50 and the inner wall of the intermediate detection housing 3 through second rotating seats 56. The setting of the spring rods 55 enables the N - pole permanent magnet 52 and the S - pole permanent magnet 54 to always contact the subsea pipeline 1, thus forming a closed magnetic field.

[0042] A detection method includes the following steps:

[0043] Step 1: Lift the subsea pipeline 1 in the middle to move this detection device to the outside of the subsea pipeline 1, cancel the middle lift, and clamp and fix both ends of the subsea pipeline 1.

[0044] Step 2: The fourth drive motor 31 drives the second drive gear 32 to rotate. Driven by the meshing relationship between the second drive gear 32 and the annular tooth portions 45 of the upper and lower half outer rings 42 of the rotating ring 40, the rotating ring 40 rotates. Under the rotation of the rotating ring 40, the drive groove 46 drives the sliding column 38 to slide along the sliding groove 36 on the fixed ring 35, and the inner rolling wheel 49 on the centroid offset detection moving assembly 34 contacts the subsea pipeline 1.

[0045] Step 3: When the pressure sensor values in the upper two center offset detection moving components 34 are the same, and the pressure sensor values in the lower two center offset detection moving components 34 are the same, but the pressure sensor values in the upper two center offset detection moving components 34 are different from those in the lower two center offset detection moving components 34, it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline 1. However, at this time, both the magnetic flux leakage detection device and the subsea pipeline 1 are set horizontally. Synchronously adjust the heights of the first lower drive adjustment unit 12, the second lower drive adjustment unit 13, and the clamping mechanisms at both ends of the subsea pipeline 1 until the pressure sensor values of the four are the same;

[0046] Step 4: When the pressure sensor values in the upper two center offset detection moving components 34 are different, and the pressure sensor values in the lower two center offset detection moving components 34 are different, it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline 1, and at least one of the magnetic flux leakage detection device and the subsea pipeline 1 is not set horizontally. Respectively adjust the heights of the first lower drive adjustment unit 12, the second lower drive adjustment unit 13, and the clamping mechanisms at both ends of the subsea pipeline 1 until the pressure sensor values of the four are the same;

[0047] Step 5: In Steps 3 and 4, when adjusting the heights of the first lower drive adjustment unit 12 and the second lower drive adjustment unit 13, the first drive motor 18 drives the bidirectional screw 17 to rotate, driving the threaded sliding block 19 to move synchronously towards the middle or synchronously towards both ends. Through the rotation relationship of the height adjustment rotating rod 20, the fixed pier 14 is jacked up or lowered;

[0048] Step 6: The second drive motor 22 drives the drive worm wheel 24 to rotate. Through the meshing relationship between the drive worm wheel 24 and the driven worm 25, the driven worm 25 is driven to rotate. The driven worm 25 drives the lower drive wheel 28 to rotate through the connecting shaft 26, realizing the movement of the device outside the subsea pipeline 1 until it moves to the weld position;

[0049] Step 7: When the weld is horizontal, the second drive motor 22 drives the lower drive wheel 28 to rotate to achieve horizontal movement and uses the Hall sensor 53 for magnetic flux leakage detection; when the weld is an arc in a vertical plane, the third drive motor 29 drives the first drive gear 30 to rotate. Through the meshing relationship between the first drive gear 30 and the connecting tooth part 6 on the middle fixed ring 5, the middle fixed ring 5 is driven to move, and the middle detection housing 3 is driven to rotate, using the Hall sensor 53 for magnetic flux leakage detection; when the weld is a spiral-like weld, the second drive motor 22 and the third drive motor 29 jointly drive and cooperate to achieve driving movement along the weld path; through the setting of each drive structure, magnetic flux leakage detection of welds with different specifications and shapes is realized, making the detection versatility of this detection device wider;

[0050] Step Eight: In Step Seven, when performing magnetic flux leakage detection, the moving mating yoke 51, the N-pole permanent magnet 52, and the S-pole permanent magnet 54 are driven to fully magnetize the pipe wall of the subsea pipeline 1, forming a closed magnetic field. When reaching the position of the pipe wall defect, the magnetic resistance at the defect and its vicinity increases, causing the magnetic field near the defect to distort and generating magnetic flux leakage, which is sensed by the Hall sensor 53 to detect the position of the pipe wall defect.

[0051] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claims concerned.

Claims

1. An external magnetic flux leakage detection device for a subsea pipeline, comprising a subsea pipeline (1), characterized in that: On both sides outside the subsea pipeline (1), a first side detection housing (2) and a second side detection housing (4) are provided. The first side detection housing (2) and the second side detection housing (4) have the same structure. The first side detection housing (2) and the second side detection housing (4) both include an annular housing portion (9). In the middle of the upper end inside the annular housing portion (9), a fourth driving motor (31) is installed through a motor bracket. At the output shaft end of the fourth driving motor (31), a second driving gear (32) is installed through a keyway. On the outer side inside the annular housing portion (9), a center offset detection driving component (33) is provided. The center offset detection driving component (33) includes a fixed ring (35) and a rotating ring (40). The fixed ring (35) is welded and fixed to the annular housing portion (9). The rotating ring (40) includes an upper half ring (41). On the outer side of the upper half ring (41) close to the second driving gear (32), a lower half outer ring (42) is integrally connected. On the inner side of the upper half ring (41) close to the second driving gear (32), a lower half inner ring (43) is integrally connected. An annular channel (44) is formed between the upper half ring (41), the lower half outer ring (42), and the lower half inner ring (43). The second driving gear (32) is located inside the annular channel (44). The diameter of the second driving gear (32) is smaller than the ring diameter of the annular channel (44). On the inner side surface of the lower half outer ring (42), an annular tooth portion (45) is provided. The annular tooth portion (45) meshes with the second driving gear (32). At both ends of the other side of the upper half ring (41), driving grooves (46) are opened. The driving grooves (46) are inclined. At the position corresponding to the driving grooves (46) on the fixed ring (35), sliding grooves (36) are provided. In the middle of the inner side of the sliding groove (36), a limiting groove (37) is opened. A sliding column (38) is slidably connected inside the sliding groove (36). The width of the sliding groove (36) is the same as the diameter of the sliding column (38). One end of the sliding column (38) extends into the driving groove (46). The width of the driving groove (46) is the same as the diameter of the sliding column (38). At the position corresponding to the limiting groove (37) on the outside of the sliding column (38), a limiting ring (39) is provided. The width of the limiting groove (37) is the same as the outer diameter of the limiting ring (39). The limiting ring (39) is fixed to the sliding column (38). On the side of the sliding column (38) away from the rotating ring (40), a center offset detection moving component (34) is provided. The center offset detection moving component (34) includes an L-shaped fixed column (47). The L-shaped fixed column (47) is fixed to the sliding column (38). At both ends of the inner side of the L-shaped fixed column (47), fixed side plates (48) are integrally connected. Between each group of two fixed side plates (48), an inner rolling wheel (49) is rotatably connected through a shaft. The inner rolling wheel (49) is in contact with the subsea pipeline (1). The center offset detection moving component (34) further includes a pressure sensor; When the pressure sensor values in the two upper center - offset detection moving components (34) are the same, and the pressure sensor values in the two lower center - offset detection moving components (34) are the same, but the pressure sensor values in the two upper center - offset detection moving components (34) are different from those in the two lower center - offset detection moving components (34), it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline (1). However, at this time, both the magnetic flux leakage detection device and the subsea pipeline (1) are set horizontally; When the pressure sensor values in the two upper center - offset detection moving components (34) are different, and the pressure sensor values in the two lower center - offset detection moving components (34) are different, it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline (1), and at least one of the magnetic flux leakage detection device and the subsea pipeline (1) is not set horizontally. By judging the relative position relationship between the detection device and the subsea pipeline (1) through the pressure sensor values in the four center - offset detection moving components (34), subsequent adjustment can be carried out, making the subsequent arc - shaped weld air leakage detection more accurate.

2. The magnetic flux leakage detection device for submarine pipelines according to claim 1, wherein: A first lower driving and adjusting unit (12) is arranged at the lower end outside the first - side detection housing (2), and a second lower driving and adjusting unit (13) is arranged at the lower end outside the second - side detection housing (4). The first lower driving and adjusting unit (12) and the second lower driving and adjusting unit (13) have the same structure.

3. The magnetic flux leakage detection device for submarine pipelines according to claim 2, wherein: Both the first lower driving and adjusting unit (12) and the second lower driving and adjusting unit (13) include a fixed pier (14) and a lower fixing plate (15). The fixed pier (14) is located at the upper end of the lower fixing plate (15). The fixed pier (14) is welded and fixed to the first - side detection housing (2) or the second - side detection housing (4). At the front and rear ends of the upper end of the lower fixing plate (15), fixed bearing seats (16) are welded and fixed. A first driving motor (18) is installed at the rear end of the rear fixed bearing seat (16). A bidirectional screw (17) is installed between the two fixed bearing seats (16) along the output shaft end of the first driving motor (18). Threaded sliding blocks (19) are arranged at the front and rear ends of the outside of the bidirectional screw (17). The threaded sliding blocks (19) are thread - connected to the bidirectional screw (17), and the threaded sliding blocks (19) are in limit sliding connection with the lower fixing plate (15). A height - adjusting rotating rod (20) is rotatably connected to the threaded sliding block (19) through a shaft. The other end of the height - adjusting rotating rod (20) is rotatably connected to a first rotating seat (21) through a shaft. The first rotating seat (21) is welded and fixed to the fixed pier (14).

4. The magnetic flux leakage detection device for submarine pipelines according to claim 3, wherein: A fixed vertical plate (23) is fixedly connected to the middle of the lower end of the lower fixing plate (15). A second driving motor (22) is installed inside the fixed vertical plate (23). A driving worm gear (24) is installed along the output shaft end of the second driving motor (22) on the other side of the fixed vertical plate (23). A driven worm (25) is meshed and connected to the lower end of the driving worm gear (24). Connecting shafts (26) are integrally connected to both ends of the driven worm (25). Mounting vertical plates (27) are arranged at both ends of the lower end of the lower fixing plate (15). A lower driving wheel (28) is installed between each group of two mounting vertical plates (27). The other end of the connecting shaft (26) passes through the inner mounting vertical plate (27) and is connected to the lower driving wheel (28).

5. The magnetic flux leakage detection device for submarine pipelines according to claim 4, wherein: A middle detection housing (3) is arranged in the middle of the outside of the submarine pipeline (1). Side sealing rings (7) are fixedly connected to both sides of the middle detection housing (3). The inner sides of the first side detection housing (2) and the second side detection housing (4) both extend into the inside of the middle detection housing (3). The side sealing rings (7) are rotatably connected to the first side detection housing (2) and the second side detection housing (4) through ball bearings (8). Middle fixing rings (5) are fixedly connected to both sides inside the middle detection housing (3). Connecting tooth parts (6) are arranged on the inner surface of the middle fixing rings (5). A third driving motor (29) is installed on the upper inner side of the first side detection housing (2) and the second side detection housing (4) through a motor bracket. A first driving gear (30) is installed at the output shaft end of the third driving motor (29). The first driving gear (30) is meshed with the connecting tooth parts (6).

6. The magnetic flux leakage detection device for submarine pipelines according to claim 5, characterized in that: A connecting plate (50) is arranged on the outside between the two middle fixing rings (5) inside the middle detection housing (3). An armature (51) is installed at one end of the connecting plate (50) close to the submarine pipeline (1). An N - pole permanent magnet (52) is installed on one side of the other end of the armature (51). A Hall sensor (53) is installed in the middle of the other end of the armature (51). An S - pole permanent magnet (54) is installed on the other side of the other end of the armature (51). Spring rods (55) are arranged on both sides between the connecting plate (50) and the inner wall of the middle detection housing (3). Both ends of the spring rods (55) are rotatably connected to the connecting plate (50) and the inner wall of the middle detection housing (3) through second rotating seats (56).

7. The magnetic flux leakage detection device for submarine pipelines according to claim 1, characterized in that: The first side detection housing (2) and the second side detection housing (4) further include a horn - shaped housing part (10). The horn - shaped housing part (10) is welded and fixed to the outside of the annular housing part (9). A circular groove (11) is opened in the middle of the outer surface of the horn - shaped housing part (10). The diameter of the circular groove (11) is larger than the diameter of the submarine pipeline (1).

8. A detection method, implemented based on the magnetic flux leakage detection device for submarine pipelines described in claim 6, characterized in that, It includes the following steps: Step 1: Lift the middle of the submarine pipeline (1) to move this detection device to the outside of the submarine pipeline (1), cancel the middle lift, and clamp and fix both ends of the submarine pipeline (1). Step 2: The fourth driving motor (31) drives the second driving gear (32) to rotate. Through the meshing relationship between the second driving gear (32) and the annular tooth part (45) of the upper and lower half outer rings (42) of the rotating ring (40), the rotating ring (40) is driven to rotate. Under the action of the rotation of the rotating ring (40), the driving groove (46) drives the sliding column (38) to slide along the sliding groove (36) on the fixed ring (35), and the inner rolling wheel (49) on the center offset detection and moving component (34) contacts the subsea pipeline (1). Step 3: When the pressure sensor values in the upper two center offset detection and moving components (34) are the same, and the pressure sensor values in the lower two center offset detection and moving components (34) are the same, but the pressure sensor values in the upper two center offset detection and moving components (34) are different from the pressure sensor values in the lower two center offset detection and moving components (34), it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline (1). However, at this time, both the magnetic flux leakage detection device and the subsea pipeline (1) are set horizontally. Synchronously adjust the heights of the first lower driving adjustment unit (12), the second lower driving adjustment unit (13), and the clamping mechanisms at both ends of the subsea pipeline (1) until the pressure sensor values of the four are the same. Step 4: When the pressure sensor values in the upper two center offset detection and moving components (34) are different, and the pressure sensor values in the lower two center offset detection and moving components (34) are different, it indicates that the center line of the magnetic flux leakage detection device is not collinear with the center line of the subsea pipeline (1), and at least one of the magnetic flux leakage detection device and the subsea pipeline (1) is not set horizontally. Adjust the heights of the first lower driving adjustment unit (12), the second lower driving adjustment unit (13), and the clamping mechanisms at both ends of the subsea pipeline (1) respectively until the pressure sensor values of the four are the same. Step 5: In Steps 3 and 4, when adjusting the heights of the first lower driving adjustment unit (12) and the second lower driving adjustment unit (13), the first driving motor (18) drives the bidirectional screw (17) to rotate, driving the threaded sliding block (19) to move synchronously towards the middle or synchronously towards both ends. Through the rotation relationship of the height adjustment rotating rod (20), the fixed pier (14) is jacked up or lowered. Step 6: The second driving motor (22) drives the driving worm gear (24) to rotate. Through the meshing relationship between the driving worm gear (24) and the driven worm (25), the driven worm (25) is driven to rotate. The driven worm (25) drives the lower driving wheel (28) to rotate through the connecting shaft (26), realizing the movement of the device outside the subsea pipeline (1) until it moves to the weld position. Step Seven: When the weld seam is horizontal, the second drive motor (22) drives the lower drive wheel (28) to rotate to achieve horizontal movement and uses the Hall sensor (53) for magnetic flux leakage detection; when the weld seam is an arc on a vertical plane, the third drive motor (29) drives the first drive gear (30) to rotate, and drives the intermediate fixed ring (5) to move through the meshing relationship between the first drive gear (30) and the connecting tooth part (6) on the intermediate fixed ring (5), the intermediate detection housing (3) is driven to rotate, and the Hall sensor (53) is used for magnetic flux leakage detection; when the weld seam is a spiral-like weld seam, the second drive motor (22) and the third drive motor (29) jointly drive and cooperate to achieve driving movement along the weld seam path. Step Eight: In Step Seven, when performing magnetic flux leakage detection, the yoke iron (51), the N-pole permanent magnet (52) and the S-pole permanent magnet (54) are driven and cooperated to fully magnetize the pipe wall of the subsea pipeline (1) to form a closed magnetic field. When reaching the defect position of the pipe wall, the magnetic resistance at the defect and its vicinity increases, causing the magnetic field near the defect to distort, generating magnetic flux leakage, which is sensed by the Hall sensor (53) to detect the defect position of the pipe wall.

Images