Buried pipeline defect detection device

Abstract

The invention relates to a buried pipeline defect detection device, which belongs to the buried pipeline nondestructive testing technology, and comprises a magnetic focusing mechanism, the magnetic focusing mechanism comprises a chassis, and each rotating frame unit can slide left and right around a fixed shaft; at least one exciting coil posture adjusting device is arranged on each rotating frame unit in a sliding mode, an exciting coil is arranged in each exciting coil posture adjusting device, and the exciting coils can rotate in the up-down direction and the front-back direction in the exciting coil posture adjusting devices; wherein the exciting coil posture adjuster can slide left and right around the fixed shaft along with the rotating frame unit so as to adjust the position of the exciting coil on the exciting coil posture adjuster, and the exciting coil posture adjuster can slide up and down on the rotating frame unit so as to adjust the height of the exciting coil; the exciting coils can also adjust the postures of the exciting coils by turning over in the up-down direction and the front-back direction in the exciting coil posture adjusting devices, so that the exciting coils in the exciting coil posture adjusting devices on the multiple rotating frame units reach the condition of magnetic focusing.

Description

Technical Field

[0001] The invention belongs to the field of nondestructive testing of buried pipelines, and in particular relates to a device for detecting defects in buried pipelines. Background Art

[0002] Buried pipelines play a vital role in oil and gas transportation, with advantages such as high efficiency, low cost, large operation scale and good stability. However, with the increase of pipeline service life, pipeline corrosion problem is becoming more and more serious. Pipeline corrosion will not only cause environmental pollution but also cause serious pipeline safety accidents. Therefore, the safety and reliability of pipelines have received more and more attention in recent years. A set of efficient and convenient buried pipeline corrosion defect detection equipment is of great significance to the safe operation of buried pipelines.

[0003] Transient electromagnetic detection technology is widely used in underground mineral exploration, groundwater resource investigation, underground pipeline defect detection, environmental geological investigation and other fields. The principle of transient electromagnetic detection is to apply a pulse current signal to the transmitting coil through the transmitter. The transmitting coil generates a stable primary magnetic field in space and diffuses underground, and then instantly turns off the excitation current to make the primary magnetic field disappear. According to the principle of electromagnetic induction, the surface of the underground metal pipeline generates an eddy current effect to form a secondary magnetic field to hinder the disappearance of the primary magnetic field. With the resistance of the pipe body itself and the ohmic consumption of the surrounding medium, the secondary magnetic field will gradually decay to zero. The entire process of the disappearance of the secondary magnetic field is received by the receiving coil and expressed in the form of voltage. The buried pipeline defect information is judged by analyzing the change law of the secondary field received by the receiving coil over time.

[0004] At present, the common buried pipeline detection methods at home and abroad are divided into buried pipeline external detection and buried pipeline internal detection. Most of the buried pipeline internal detection technologies are invasive and destructive detection. This detection method is costly, time-consuming and will affect the pipeline. Some technologies such as weak magnetic detection, metal magnetic memory detection, and close-interval potential detection in the buried pipeline external detection technology have low detection efficiency and low accuracy. Transient electromagnetic detection technology is one of the buried pipeline external detection technologies. It has the advantages of high efficiency, speed, high sensitivity, and no need for excavation detection. It is widely used in the field of pipeline detection. The excitation coil is an extremely important part of the transient electromagnetic detection technology. The current excitation coil has the problems of insufficient excitation magnetic induction intensity and poor focusing performance. These problems will lead to insufficient detection accuracy of buried pipeline defects.

[0005] In short, the current accuracy of detecting buried pipeline defects is relatively low. Summary of the invention

[0006] In view of the above problems, an object of the present invention is to provide a buried pipeline defect detection device to solve the problem of low accuracy in the current detection of buried pipeline defects.

[0007] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a buried pipeline defect detection device, comprising a magnetic signal transmitter, a reflection signal receiver and a transient electromagnetic controller, wherein the magnetic signal transmitter is equipped with at least one excitation coil, the reflection signal receiver is equipped with a receiving coil, the excitation coil of the magnetic signal transmitter and the receiving coil of the reflection signal receiver are respectively connected to the transient electromagnetic controller, the magnetic signal transmitter, the reflection signal receiver and the transient electromagnetic controller are all arranged above the buried pipeline, and the magnetic signal transmitter is a magnetic focusing mechanism. The magnetic focusing mechanism comprises a chassis, the chassis is circular in shape, a fixed axis is arranged on the center line passing through the center of the chassis, a plurality of rotating frame units are arranged on the chassis, the rotating frame units are arc-shaped, each of the rotating frame units can slide left and right around the fixed axis, and the plurality of rotating frame units are sequentially connected in the rotating path of the chassis to form a circular arc surface; At least one excitation coil posture adjuster is slidably provided on each of the rotating frame units, and an excitation coil is provided in each of the excitation coil posture adjusters. The shape of the excitation coil posture adjuster is rectangular, and the excitation coil is a square coil. The excitation coil can rotate in the up-down direction and the front-back direction in the excitation coil posture adjuster respectively; Among them, the excitation coil attitude adjuster can slide left and right around the fixed axis with the rotating frame unit to adjust the position of the excitation coil thereon, the excitation coil attitude adjuster can slide up and down on the rotating frame unit to adjust the height of the excitation coil, and the excitation coil can also adjust the posture of the excitation coil by flipping in the up and down directions and front and back directions within the excitation coil attitude adjuster, so that the excitation coils in the excitation coil attitude adjusters on several rotating frame units meet the conditions of magnetic focusing, and the conditions of magnetic focusing are that the magnetic fields excited by several excitation coils are just focused on the buried pipeline.

[0008] Further, the excitation coil posture adjuster comprises an outer frame, an upper and lower posture adjustment mechanism, a middle frame, a front and rear posture adjuster and an inner frame, wherein the inner frame is a square frame, and the excitation coil is installed in the inner frame; the inner frame is arranged inside the middle frame, and a second posture adjustment axis is arranged between the inner frame and the middle frame as a pivot, and the front and rear posture adjuster is arranged on the second posture adjustment axis; the middle frame is arranged inside the outer frame, and a first posture adjustment axis is arranged between the middle frame and the outer frame as a pivot, and the upper and lower posture adjustment mechanism is arranged on the first posture adjustment axis; the first posture adjustment axis and the second posture adjustment axis are perpendicular to each other; Among them, the up and down posture adjustment mechanism is used to realize the flipping of the excitation coil in the up and down direction by controlling the rotation of the front and back posture adjusters; the front and back posture adjusters are used to realize the flipping of the excitation coil in the left and right direction by controlling the rotation of the inner frame.

[0009] Furthermore, the outer frame includes a left guide module, a right guide module, an upper fixed plate and a lower fixed plate, and the left guide module, the upper fixed plate, the right guide module and the lower fixed plate are connected end to end in sequence to form the outer frame; the first posture adjustment axis includes an upper connecting axis and a lower connecting axis, and the extension lines of the upper connecting axis and the lower connecting axis are located on the same straight line, together forming the first posture adjustment axis; the upper side of the middle frame is pivotally connected to the upper fixed plate through the upper connecting axis of the first posture adjustment axis, and the lower side of the middle frame is pivotally connected to the upper fixed plate through the lower connecting axis of the first posture adjustment axis The shaft is pivotally connected to the lower fixed plate, and the up and down posture adjustment mechanism is arranged on the lower connecting shaft of the first posture adjustment shaft; the second posture adjustment shaft includes a left connecting shaft and a right connecting shaft, and the extension lines of the left connecting shaft and the right connecting shaft are located on the same straight line, together forming the second posture adjustment shaft; the left side of the inner frame is pivotally connected to the left side plate of the middle frame through the left connecting shaft of the second posture adjustment shaft, and the right side of the inner frame is pivotally connected to the right side plate of the middle frame through the right connecting shaft of the second posture adjustment shaft, and the front and rear posture adjusters are arranged on the left connecting shaft of the second posture adjustment shaft.

[0010] Furthermore, the middle frame and the inner frame are both square frames, and are both formed by connecting an upper side plate, a right side plate, a lower side plate and a left side plate in sequence end to end; the upper side plate of the middle frame is pivotally connected to the upper fixed plate via an upper connecting shaft, and the lower side plate of the middle frame is pivotally connected to the lower fixed plate via a lower connecting shaft; the up and down posture adjustment mechanism is located in the gap between the lower fixed plate and the lower side plate of the middle frame; the left side of the inner frame is pivotally connected to the left side plate of the middle frame via a left connecting shaft, and the right side plate of the inner frame is pivotally connected to the right side wall of the middle frame; the front and rear posture adjuster is located in the gap between the left side plate of the middle frame and the left side plate of the inner frame.

[0011] Furthermore, the up and down posture adjustment mechanism and the front and back posture adjustment device both include a motor, a coupling and a bevel gear set, the bevel gear set includes a driving wheel, a left transmission wheel, a right transmission wheel and an auxiliary wheel, the driving wheel, the left transmission wheel, the right transmission wheel and the auxiliary wheel are all bevel gears, the left transmission wheel and the right transmission wheel are arranged in pairs on the lower connecting shaft of the first posture adjustment shaft or the left connecting shaft of the second posture adjustment shaft; the driving wheel and the auxiliary wheel are arranged in pairs between the left transmission wheel and the right transmission wheel, and the two ends of the driving wheel are respectively meshed with one end of the left transmission wheel and the right transmission wheel, and the other ends of the left transmission wheel and the right transmission wheel are respectively meshed with the auxiliary wheel; the output shaft of the motor is fixedly connected to the driving wheel of the bevel gear set through the coupling.

[0012] Furthermore, the left transmission wheel and the right transmission wheel are integrally formed with the lower connecting shaft of the first posture adjustment shaft or the left connecting shaft of the second posture adjustment shaft to form a large gear with a shaft.

[0013] Further, the motor is equipped with a motor support, the motor support of the upper and lower posture adjustment mechanism is arranged on the inner side of the lower fixed plate; the motor support of the front and rear posture adjuster is arranged on the inner side of the left side plate of the middle frame; The driving wheel is provided with a driving wheel support, the driving wheel support of the upper and lower posture adjustment mechanism is arranged on the inner side of the lower fixed plate; the driving wheel support of the front and rear posture adjustment device is arranged on the inner side of the left side plate of the middle frame; The auxiliary wheel is provided with an auxiliary wheel support, the auxiliary wheel support of the upper and lower posture adjustment mechanism is arranged on the inner side of the lower fixed plate; the auxiliary wheel support of the front and rear posture adjustment device is arranged on the inner side of the left side plate of the middle frame; The left transmission wheel and the right transmission wheel of the up-down posture adjustment mechanism are arranged in pairs on the lower connecting shaft of the first posture adjustment shaft; The left transmission wheel and the right transmission wheel of the up-and-down posture adjustment mechanism are arranged in pairs on the left connecting shaft of the second posture adjustment shaft.

[0014] Furthermore, a support frame is arranged at the center of the chassis, and the fixed axis is arranged on the support frame; the transient electromagnetic controller is arranged on the back side of the chassis of the magnetic focusing mechanism and is opposite to the support frame.

[0015] Furthermore, the outer ring of the chassis is equally divided into four parts, and an arc-shaped slide rail is provided on the outer ring of each part; Four rotating frame units are arranged on the chassis, and each rotating frame unit is provided with a pivot hole at the top and a slider assembly at the bottom; The pivot hole of the rotating frame unit is penetrated on the fixed shaft, and the slider assemblies of the four rotating frame units are respectively arranged on the four arc-shaped slide rails of the outer ring of the chassis.

[0016] Furthermore, an excitation coil posture adjuster is respectively provided at the upper and lower parts of the two arc-shaped rods of each rotating frame unit. The upper parts of the four rotating frame units form four excitation coil posture adjusters located thereon, and the four excitation coil posture adjusters located thereon are of equal height; The lower parts of the four rotating frame units form four excitation coil posture adjusters located therebelow, and the four excitation coil posture adjusters located therebelow are of the same height.

[0017] Furthermore, the rotating frame unit includes two arc-shaped rods and a transverse plate, the top ends of the two arc-shaped rods are connected together through the transverse plate, the slider assemblies are respectively arranged at the bottom ends of the two arc-shaped rods, and the pivot hole is arranged at the top end of the transverse plate of the rotating frame unit; the left guide module and the right guide module on both sides of the outer frame are respectively arranged on the arc-shaped rods on both sides of the rotating frame unit.

[0018] The camshaft of the second guide wheel assembly is connected to the camshaft of the second guide wheel assembly through a sliding pre-tightening mechanism, and the sliding pre-tightening mechanism comprises a first upper guide wheel, a second upper guide wheel, a first lower guide wheel, a pair of pre-tightening springs and two pairs of clamping sheets, wherein the top surface and the bottom surface of the camshaft of the camshaft unit are respectively provided with sliding grooves, the first upper guide wheel and the second upper guide wheel are respectively arranged in the sliding grooves on the top surface of the camshaft, and the first lower guide wheel is arranged in the sliding grooves on the bottom surface of the camshaft, the first upper guide wheel, the second upper guide wheel and the first lower guide wheel are respectively penetrated by screws, and the screws pass through the side panels of the left guide module and the right guide module, and nuts are respectively arranged at both ends of each screw, and the side panels of the left guide module or the right guide module are locked to the camshaft of the camshaft unit by tightening the nuts at both ends of the screw; Three support columns are respectively arranged on the side panels of the left guide module and the right guide module opposite to the screw rods of the first upper guide wheel, the second upper guide wheel and the first lower guide wheel, and each support column and its corresponding screw rod are pre-tightened by a pair of pre-tightening springs located on both sides of the arc rod; A pair of bolts are disposed across the side panels of the left guide module and the right guide module and the arc-shaped rod of the rotating frame unit, and clamping plates and nuts are respectively passed through the bolts. By tightening the nuts and pushing the clamping plates, the side panels of the left guide module or the right guide module are pressed against the arc-shaped rod of the rotating frame unit.

[0019] Furthermore, the buried pipeline defect detection device also includes a mobile body, which includes a frame, the frame is equipped with eight shock-absorbing tires, and the reflection signal receiver is arranged inside the frame; the magnetic focusing mechanism is arranged on the mobile body.

[0020] In a second aspect, the present invention discloses a method for detecting defects in a buried pipeline, using the above-mentioned buried pipeline defect detection device, the method comprising the following steps: Step A: Adjust the position and posture of the excitation coil so that the magnetic field excited by the excitation coil in the excitation coil posture adjuster on the plurality of rotating frame units reaches the condition of magnetic focusing, including the following steps: Step A1: adjusting the position of the excitation coil so that the magnetic field excited by the excitation coil in the excitation coil posture adjuster on the plurality of rotating frame units reaches the position under the condition of magnetic focusing, comprising the following steps: the excitation coil posture adjuster slides left and right around the fixed axis along with the rotating frame unit to adjust the position of the excitation coil thereon; the excitation coil posture adjuster slides up and down on the arc rod of the rotating frame unit to adjust the height of the excitation coil; Step A2: Adjust the posture of the excitation coil itself so that the magnetic field excited by the excitation coil in the excitation coil posture adjuster on several rotating frame units reaches the posture when the condition of magnetic focusing is met, including the following specific steps: adjust the posture of the excitation coil by flipping it in the up and down directions and the front and back directions in the excitation coil posture adjuster to achieve a posture that meets the condition of magnetic focusing.

[0021] Step B: the transient electromagnetic controller simultaneously sends a pulse excitation signal to the excitation coils in the excitation coil posture adjusters on the plurality of rotating frame units, so that the plurality of excitation coils simultaneously excite a magnetic field that satisfies the conditions for magnetic focusing; Step C: the magnetic field of the magnetic focusing condition is just focused on the buried pipeline, so that the buried pipeline generates an induced magnetic field, and the receiving coil of the reflection signal receiver receives the induced magnetic field generated by the buried pipeline; Step D: Defects of the buried pipeline are identified based on the induced magnetic field generated by the buried pipeline received by the receiving coil.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a buried pipeline defect detection device, which is suitable for non-destructive detection of buried pipeline defects. The excitation coil posture adjuster can slide left and right around the fixed axis with the rotating frame unit to adjust the position of the excitation coil thereon, and the excitation coil posture adjuster can slide up and down in the rotating frame unit to adjust the height of the excitation coil; the excitation coil can also adjust the posture of the excitation coil by flipping in the up and down direction and the front and back direction in the excitation coil posture adjuster, which can realize the posture adjustment of the excitation coil in multiple directions at any angle in space so that it has an extremely flexible posture, so that the excitation coils in the excitation coil posture adjusters on the rotating frame units reach the condition of magnetic focusing, wherein the condition of magnetic focusing is that the magnetic field excited by the several excitation coils is just focused on the buried pipeline, which not only includes adjusting the position of the several excitation coils, but also includes adjusting the posture of the excitation coil itself. A buried pipeline defect detection device disclosed by the present invention, the magnetic field generated by the several excitation coils is focused on the buried pipeline, and the receiving coil can accurately receive the induced magnetic field generated by the buried pipeline, which helps us to more easily distinguish and quantify the defects of the buried pipeline, improves the accuracy of the defect detection of the buried pipeline, and is more conducive to the realization of non-destructive detection of the defects of the buried pipeline.

[0023] In addition, the present invention also has the following advantages: (1) Currently, most transient electromagnetic methods for detecting buried pipeline defects use a single square coil as the excitation coil. To address the problem of insufficient excitation magnetic induction intensity and poor focusing performance of the excitation coil, the present invention uses four excitation coil attitude adjuster moving slides and eight adjustable moving coils to achieve magnetic induction intensity enhancement and magnetic focusing functions. The excitation coil attitude adjuster can be adjusted at any angle and in multiple directions in space, thereby better adapting to buried pipelines of various sizes and depths.

[0024] (2) The frame is equipped with 8 shock-absorbing tires with independent suspension systems. Each wheel has an independent suspension system and is not directly connected to the suspension systems of other wheels. Compared with the traditional axle suspension system, it has better suspension stability, better road adaptability and better chassis controllability. The independent suspension system enables the overall frame to significantly reduce the bumps and swaying of the chassis when dealing with potholes and uneven roads, improve grip and stability, and be more stable when the chassis turns and changes lanes. The frame of the present invention uses 8 wheels, which can better distribute the weight and have a greater carrying capacity, thereby improving the stability of the vehicle. Since most buried pipelines are buried under harsh roads, using 8 wheels has more grounding points to provide better traction and stability, so it can better pass through complex and rugged terrain and roads. At the same time, more wheels can provide better steering and turning performance and better controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1It is a schematic diagram of the overall structure of the buried pipeline defect detection device provided in Example 1 of the present invention; Figure 2 is a schematic structural diagram of a magnetic focusing mechanism provided in Example 1 of the present invention; Figure 3 is a structural schematic diagram of a chassis of a magnetic focusing mechanism provided in Example 1 of the present invention; Figure 4 is a schematic diagram of the connection between the excitation coil posture adjuster and the rotating frame unit provided in Example 1 of the present invention; Figure 5 is a three-dimensional view of the excitation coil posture adjuster provided in Example 1 of the present invention; Figure 6 is a front view of the excitation coil posture adjuster provided in Example 1 of the present invention; Figure 7 yes Figure 6 Schematic diagram of the up and down posture adjustment mechanism in ; Figure 8 yes Figure 6 Schematic diagram of the front and rear posture adjustment mechanism; Fig. 9 yes Figure 8 The structure of the middle bevel gear set and its connection diagram; Fig.10 is a top view of the rotating frame unit provided in Example 1 of the present invention; Fig.11 It is a three-dimensional view of a rotating frame unit having a side panel of a right guide module provided in Example 1 of the present invention and an upper top panel; Fig.12 yes Fig.11 A partial enlarged view of the middle A; Fig.13 It is a three-dimensional view of the rotating frame unit without the upper top plate of the side panel of the right guide module provided in Example 1 of the present invention; Fig.14 yes Fig.13 A partial enlarged view of point B in the middle; Fig.15 is a schematic diagram of a reflected signal receiver provided in Embodiment 1 of the present invention being arranged on a frame of a moving vehicle; Fig.16 It is a schematic diagram of the structure of the mobile vehicle body provided in Example 1 of the present invention.

[0026] Description of reference numerals: 1- chassis, 10- support frame, 11- fixed axis, 12- arc slide rail; 2-rotating frame unit, 20-transverse plate, 21-arc-shaped rod, 22-slider assembly, 23-pivot hole; 3-excitation coil posture adjuster, 30-excitation coil; 31-outer frame, 311-left guide module, 313-right guide module, 312-upper fixing plate, 314-lower fixing plate; 32-Medium frame; 33-Inner frame; 41-up and down posture adjustment mechanism, 410-first posture adjustment axis; 42-front and rear posture adjusters, 420-second posture adjustment axis; 51-motor, 52-coupling, 53-conical gear set, 531-driving wheel, 532-left transmission wheel, 533-right transmission wheel, 534-auxiliary wheel, 61-first upper guide wheel, 62-second upper guide wheel, 63-first lower guide wheel, 64-preload spring, 640-support column, 65-clamping sheet; 7-mobile vehicle body, 70-reflection signal receiver, 71-vehicle frame, 72-shock-absorbing tire. DETAILED DESCRIPTION

[0027] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0028] Embodiment 1: A buried pipeline defect detection device Embodiment 1 of the present invention provides a buried pipeline defect detection device, and its structure and connection relationship are described in detail below with reference to the accompanying drawings.

[0029] The buried pipeline defect detection device includes a magnetic signal transmitter, a reflection signal receiver 70 and a transient electromagnetic controller, wherein the magnetic signal transmitter is equipped with at least one excitation coil, the reflection signal receiver 70 is equipped with a receiving coil, the excitation coil of the magnetic signal transmitter and the receiving coil of the reflection signal receiver 70 are respectively connected to the transient electromagnetic controller, and the magnetic signal transmitter, the reflection signal receiver 70 and the transient electromagnetic controller are all arranged above the buried pipeline. The magnetic signal transmitter of the present invention is a magnetic focusing mechanism.

[0030] refer to Figure 1 , Fig.15 and Fig.16 The buried pipeline defect detection device includes a mobile body 7, the mobile body 7 includes a frame 71, the frame 71 is equipped with eight shock-absorbing tires 72, the reflection signal receiver 70 is arranged inside the frame 71; the magnetic focusing mechanism is arranged on the mobile body 7.

[0031] refer to Figure 2 and Figure 3 The magnetic focusing mechanism comprises a chassis 1, the chassis 1 is circular in shape, a fixed shaft 11 is arranged on the center line passing through the center of the chassis 1, a plurality of rotating frame units 2 are arranged on the chassis 1, the rotating frame units 2 are arc-shaped, each of the rotating frame units 2 can slide left and right around the fixed shaft 11, and a plurality of rotating frame units 2 are sequentially connected in the rotation path of the chassis 1 to form a circular arc surface; At least one excitation coil posture adjuster 3 is slidably provided on each of the rotating frame units 2, and an excitation coil 30 is provided in each of the excitation coil posture adjusters 3. The shape of the excitation coil posture adjuster 3 is rectangular, and the excitation coil 30 is a square coil. The excitation coil 30 can rotate in the excitation coil posture adjuster 3 in the up-down direction and the front-back direction respectively; Among them, the excitation coil attitude adjuster 3 can slide left and right around the fixed axis 11 with the rotating frame unit 2 to adjust the position of the excitation coil 30 thereon, the excitation coil attitude adjuster 3 can slide up and down on the rotating frame unit 2 to adjust the height of the excitation coil 30, and the excitation coil 30 can also adjust the posture of the excitation coil 30 by flipping in the up and down directions and front and back directions within the excitation coil attitude adjuster 3, so that the excitation coils 30 in the excitation coil attitude adjusters 3 on several rotating frame units 2 can reach the magnetic focusing condition, and the magnetic focusing condition is that the magnetic field excited by several excitation coils 30 is just focused on the buried pipeline.

[0032] Since the excitation coil 30 can be adjusted in multiple directions and postures at any angle in space, it has an extremely flexible posture. Therefore, to achieve the condition of magnetic focusing, that is, to meet the requirement that the magnetic field excited by several excitation coils 30 is focused on the buried pipeline, it not only includes adjusting the positions of several excitation coils 30, but also includes adjusting the posture of the excitation coil 30 itself.

[0033] refer to Figures 4 to 6 The excitation coil posture adjuster 3 includes an outer frame 31, an upper and lower posture adjusting mechanism 41, a middle frame 32, a front and rear posture adjusting device 42 and an inner frame 33. The inner frame 33 is a square frame, and the excitation coil 30 is installed in the inner frame 33; The inner frame 33 is arranged inside the middle frame 32, and a second posture adjustment shaft 420 is arranged between the inner frame 33 and the middle frame 32 as a pivot, and the front and rear posture adjuster 42 is arranged on the second posture adjustment shaft 420; The middle frame 32 is arranged inside the outer frame 31, and a first posture adjustment shaft 410 is arranged between the middle frame 32 and the outer frame 31 as a pivot, and the up and down posture adjustment mechanism 41 is arranged on the first posture adjustment shaft 410; The first posture adjustment axis 410 and the second posture adjustment axis 420 are perpendicular to each other; The up-down posture adjustment mechanism 41 is used to realize the flipping of the excitation coil 30 in the up-down direction by controlling the rotation of the front-back posture adjuster 42; The front-rear posture adjuster 42 is used to realize the flipping of the excitation coil 30 in the left-right direction by controlling the rotation of the inner frame 33 .

[0034] Continue to refer Figure 2 The outer frame 31 includes a left guide module 311, a right guide module 313, an upper fixing plate 312 and a lower fixing plate 314. The left guide module 311, the upper fixing plate 312, the right guide module 313 and the lower fixing plate 314 are connected end to end in sequence to form the outer frame 31; The first posture adjustment shaft 410 includes an upper connecting shaft and a lower connecting shaft, and the extension lines of the upper connecting shaft and the lower connecting shaft are located on the same straight line, and together constitute the first posture adjustment shaft 410; the upper side of the middle frame 32 is pivotally connected to the upper fixing plate 312 through the upper connecting shaft of the first posture adjustment shaft 410, and the lower side of the middle frame 32 is pivotally connected to the lower fixing plate 314 through the lower connecting shaft of the first posture adjustment shaft 410, and the upper and lower posture adjustment mechanism 41 is arranged on the lower connecting shaft of the first posture adjustment shaft 410; The second posture adjustment axis 420 includes a left connecting axis and a right connecting axis, and the extension lines of the left connecting axis and the right connecting axis are located on the same straight line, together constituting the second posture adjustment axis 420; the left side of the inner frame 33 is pivotally connected to the left side plate of the middle frame 32 through the left connecting axis of the second posture adjustment axis 420, and the right side of the inner frame 33 is pivotally connected to the right side plate of the middle frame 32 through the right connecting axis of the second posture adjustment axis 420, and the front and rear posture adjusters 42 are arranged on the left connecting axis of the second posture adjustment axis 420.

[0035] Specifically, the middle frame 32 and the inner frame 33 are both square frames, and are formed by connecting an upper side plate, a right side plate, a lower side plate and a left side plate end to end in sequence; The upper side plate of the middle frame 32 is pivotally connected to the upper fixing plate 312 via an upper connecting shaft, and the lower side plate of the middle frame 32 is pivotally connected to the lower fixing plate 314 via a lower connecting shaft; the upper and lower posture adjustment mechanism 41 is located in the gap between the lower fixing plate 314 and the lower side plate of the middle frame 32; The left side of the inner frame 33 is pivotally connected to the left side plate of the middle frame 32 via a left connecting shaft, and the right side plate of the inner frame 33 is pivotally connected to the right side wall of the middle frame 32; the front and rear posture adjuster 42 is located in the gap between the left side plate of the middle frame 32 and the left side plate of the inner frame 33.

[0036] refer to Figures 7 to 9 The up-down posture adjustment mechanism 41 and the front-back posture adjustment device 42 both include a motor 51, a coupling 52 and a bevel gear set 53. The bevel gear set 53 includes a driving wheel 531, a left transmission wheel 532, a right transmission wheel 533 and an auxiliary wheel 534. The driving wheel 531, the left transmission wheel 532, the right transmission wheel 533 and the auxiliary wheel 534 are all bevel gears. The left transmission wheel 532 and the right transmission wheel 533 are arranged in pairs on the lower connecting shaft of the first posture adjustment shaft 410 or the left connecting shaft of the second posture adjustment shaft 420; The driving wheel 531 and the auxiliary wheel 534 are arranged in pairs between the left transmission wheel 532 and the right transmission wheel 533, and both ends of the driving wheel 531 are respectively meshed with one end of the left transmission wheel 532 and the right transmission wheel 533, and the other ends of the left transmission wheel 532 and the right transmission wheel 533 are respectively meshed with the auxiliary wheel 534; The output shaft of the motor 51 is fixedly connected to the driving wheel 531 of the bevel gear set 53 through the coupling 52 .

[0037] Preferably, the left transmission wheel 532 and the right transmission wheel 533 are integrally formed with the lower connecting shaft of the first posture adjustment shaft 410 or the left connecting shaft of the second posture adjustment shaft 420 to form a large gear with a shaft.

[0038] Specifically, the motor 51 is provided with a motor support. The motor support of the up-down posture adjustment mechanism 41 is arranged on the inner side of the lower fixing plate 314; The motor support of the front and rear posture adjuster 42 is arranged on the inner side of the left side plate of the middle frame 32; The driving wheel 531 is provided with a driving wheel support. The driving wheel support of the up-down posture adjustment mechanism 41 is arranged on the inner side of the lower fixing plate 314; The driving wheel support of the front and rear posture adjuster 42 is arranged on the inner side of the left side plate of the middle frame 32; The auxiliary wheel 534 is provided with an auxiliary wheel support. The auxiliary wheel support of the up-and-down posture adjustment mechanism 41 is arranged on the inner side of the lower fixing plate 314; The auxiliary wheel support of the front and rear posture adjuster 42 is arranged on the inner side of the left side plate of the middle frame 32; The left transmission wheel 532 and the right transmission wheel 533 of the up-down posture adjustment mechanism 41 are arranged in pairs on the lower connecting shaft of the first posture adjustment shaft 410; The left transmission wheel 532 and the right transmission wheel 533 of the up-and-down posture adjustment mechanism 41 are arranged in pairs on the left connecting shaft of the second posture adjustment shaft 420 .

[0039] In order to ensure the strength and stability of the magnetic focusing mechanism, a support frame 10 is provided at the center of the chassis 1, and the fixed shaft 11 is provided on the support frame 10. Figure 3 shown.

[0040] Specifically, the transient electromagnetic controller is arranged on the back side of the chassis 1 of the magnetic focusing mechanism and is opposite to the support frame 10 .

[0041] Continue to refer Figure 3 The outer ring of the chassis 1 is equally divided into four parts, and an arc-shaped slide rail 12 is provided on the outer ring of each part; Four rotating frame units 2 are arranged on the chassis 1, and each rotating frame unit 2 is provided with a pivot hole 23 at the top and a slider assembly 22 at the bottom; The pivot hole 23 of the rotating frame unit 2 is penetrated on the fixed shaft 11 , and the slider assemblies 22 of the four rotating frame units 2 are respectively arranged on the four arc-shaped slide rails 12 of the outer ring of the chassis 1 .

[0042] The arc-shaped slide rail 12 is a circular dovetail groove slide rail, and when installing the slider assembly 22, an angle that adapts to the curvature of the dovetail groove slide rail is selected for installation.

[0043] The dovetail groove can improve the stability of the circular slide rail, reduce friction, and is easy to install and disassemble, and the connection is firm and not easy to loosen. The dovetail groove slider adopts a combination of a cylinder and a truncated cone to cooperate with the dovetail groove. The slider assembly 22 includes a slider, which has a smaller friction area than the traditional fully wrapped slider, reduces the friction between the slider and the slide rail, prolongs the life of the components, and reduces energy loss.

[0044] refer to Fig.10 The upper and lower parts of the two arc-shaped rods 21 of each rotating frame unit 2 are respectively provided with an excitation coil posture adjuster 3, The upper parts of the four rotating frame units 2 form four excitation coil posture adjusters 3 located thereon, and the four excitation coil posture adjusters 3 located thereon are of the same height; The lower parts of the four rotating frame units 2 form four excitation coil posture adjusters 3 located thereunder, and the four excitation coil posture adjusters 3 located thereunder are of the same height.

[0045] Among them, adjusting the slider assembly 22 of the rotating frame unit 2 to be set on the curvature radius of the arc-shaped slide rail 12 of the outer ring of the chassis 1 and adjusting the slider assembly 22 of the rotating frame unit 2 to achieve equal heights on the side panels of the left guide module 311 and the right guide module 313 are conventional technical means in this field and will not be repeated here.

[0046] As a specific implementation, the rotating frame unit 2 includes two arc-shaped rods 21 and a transverse plate 20, the top ends of the two arc-shaped rods 21 are connected together through the transverse plate 20, the slider assembly 22 is respectively arranged at the bottom ends of the two arc-shaped rods 21, and the pivot hole 23 is arranged at the top end of the transverse plate 20 of the rotating frame unit 2; The left guide module 311 and the right guide module 313 on both sides of the outer frame 31 are respectively arranged on the arc-shaped rods 21 on both sides of the rotating frame unit 2 .

[0047] refer to Figures 11 to 14 The left guide module 311 and the right guide module 313 are both provided with side panels, and the side panels of the left guide module 311 and the right guide module 313 are connected to the arc rod 21 of the rotating frame unit 2 via a sliding pre-tightening mechanism. The sliding preload mechanism includes a first upper guide wheel 61, a second upper guide wheel 62, a first lower guide wheel 63, a pair of preload springs 64 and two pairs of clamping plates 65. The top and bottom surfaces of the arc-shaped rod 21 of the rotating frame unit 2 are respectively provided with sliding grooves, the first upper guide wheel 61 and the second upper guide wheel 62 are respectively provided in the sliding grooves on the top surface of the arc-shaped rod 21, and the first lower guide wheel 63 is provided in the sliding grooves on the bottom surface of the arc-shaped rod 21, the first upper guide wheel 61, the second upper guide wheel 62, and the first lower guide wheel 63 are respectively penetrated with screws, and the screws pass through the side panels of the left guide module 311 and the right guide module 313, and nuts are respectively arranged at both ends of each screw, and the side panels of the left guide module 311 or the right guide module 313 are locked with the arc-shaped rod 21 of the rotating frame unit 2 by tightening the nuts at both ends of the screws; Support columns 640 are respectively provided on the side panels of the left guide module 311 and the right guide module 313 opposite to the screw rods of the first upper guide wheel 61, the second upper guide wheel 62 and the first lower guide wheel 63, and each support column 640 and its corresponding screw rod are pre-tightened by a pair of pre-tightening springs 64 located on both sides of the arc rod 21; A pair of bolts are disposed across the side panels of the left guide module 311 and the right guide module 313 and the arc rod 21 of the rotating frame unit 2. A clamping plate 65 and a nut are respectively passed through the bolts. By tightening the nut and pushing the clamping plate 65, the side panel of the left guide module 311 or the right guide module 313 is pressed against the arc rod 21 of the rotating frame unit 2.

[0048] Specifically, an upper top plate is disposed on the top of the side panels of the left guide module 311 and the right guide module 313 , and the side edges of the upper top plate are fixedly connected to the side edges of the side panels, and the two intersect vertically and are integrally formed.

[0049] Specifically, the first upper guide wheel 61, the second upper guide wheel 62, and the first lower guide wheel 63 are made of polyurethane material, which makes them elastic and has a pre-tightening effect.

[0050] The first upper guide wheel 61 , the second upper guide wheel 62 , and the first lower guide wheel 63 enable the left guide module 311 and the right guide module 313 to run smoothly on the slide grooves on the top and bottom surfaces of the arc rod 21 of the rotating frame unit 2 .

[0051] The preload spring 64 tensions the three guide wheels to provide better preload between the guide wheels and the slide slots, and also provides a good shock-absorbing effect.

[0052] The support column 640 can prevent the side panels of the left guide module 311 and the right guide module 313 from being deformed during the sliding process.

[0053] Among them, the arbitrary angle and multiple orientation adjustment of the excitation coil 30 is the result of the joint action of the motor, the motor seat, the coupling and the gear set, and the overall lateral size of this part is too large. If the gear set is not set for reversing rotation, the space occupied by this part in the excitation coil attitude adjuster 3 will be too large, and the space utilization rate is extremely low. Therefore, the patent of the present invention adopts the form of a gear set to change the rotation direction of the coil, so that its space utilization rate is greatly improved. In addition, the form of using a small gear to drive the large gear to rotate also increases the motor torque to better drive the coil to rotate. The gear set adopts a gear symmetrical structure, which also solves the dynamic balance problem between the gears.

[0054] Furthermore, the frame 71 is equipped with shock-absorbing tires 72 of 8 independent suspension systems, so that it can perform dynamic and stable detection when detecting defects in buried pipelines.

[0055] In order to facilitate the receiving coil of the reflected signal receiver 70 to receive the magnetic signal, the frame 71 includes an upper layer and a lower layer, and both the upper layer and the lower layer adopt a hollow structure.

[0056] In order to minimize the impact of the magnetic material used in the overall structure of the movable excitation coil magnetic focusing mechanism and the magnetic signals and stray currents in the external environment on the receiving coil, the receiving coil of the reflection signal receiver 70 is provided with a shielding cover.

[0057] Specifically, each frame 71 has an independent suspension system and is not directly connected to the suspension of other wheels. Compared with the traditional axle suspension system, it has better suspension stability, better road adaptability and better chassis controllability. The independent suspension system enables the entire frame to significantly reduce the bumps and swaying of the chassis when dealing with bumpy roads, improve grip and stability, and be more stable when the chassis turns and changes lanes.

[0058] Among them, the material used for the frame 71 is mostly carbon fiber material, which has high strength and high modulus and is light and corrosion-resistant. In addition, the carbon fiber material will not produce magnetic signal interference to the receiving coil receiving signal. The upper and lower layers of the frame 71 adopt a hollow structure, which can reduce the weight as much as possible without affecting the stability and strength of the overall structure.

[0059] Example 2: A method for detecting defects in buried pipelines Embodiment 2 of the present invention provides a method for detecting defects in a buried pipeline, using the device for detecting defects in a buried pipeline provided in Embodiment 1. The method comprises the following steps: Step A: adjusting the position and posture of the excitation coil 30 so that the magnetic field excited by the excitation coil 30 in the excitation coil posture adjuster 3 on the plurality of rotating frame units 2 reaches the condition of magnetic focusing, including the following steps: Step A1: adjusting the position of the excitation coil 30 so that the magnetic field excited by the excitation coil 30 in the excitation coil posture adjusters 3 on the plurality of rotating frame units 2 reaches the position under the condition of magnetic focusing, comprising the following steps: the excitation coil posture adjuster 3 slides left and right around the fixed axis 11 along with the rotating frame unit 2 to adjust the position of the excitation coil 30 thereon; the excitation coil posture adjuster 3 slides up and down on the arc rod 21 of the rotating frame unit 2 to adjust the height of the excitation coil 30; Step A2: Adjust the posture of the excitation coil 30 so that the magnetic field excited by the excitation coil 30 in the excitation coil posture adjuster 3 on the plurality of rotating frame units 2 reaches a posture that satisfies the magnetic focusing condition, including the following specific steps: adjust the posture of the excitation coil 30 by flipping it in the up-down direction and the front-back direction in the excitation coil posture adjuster 3 so as to achieve a posture that satisfies the magnetic focusing condition.

[0060] Step B: the transient electromagnetic controller simultaneously sends a pulse excitation signal to the excitation coils 30 in the excitation coil posture adjusters 3 on the plurality of rotating frame units 2, and the plurality of excitation coils 30 simultaneously excite a magnetic field that satisfies the conditions for magnetic focusing; Step C: The magnetic field of the magnetic focusing condition is just focused on the buried pipeline, so that the buried pipeline generates an induced magnetic field, and the receiving coil of the reflection signal receiver 70 receives the induced magnetic field generated by the buried pipeline; Step D: Defects of the buried pipeline are identified based on the induced magnetic field generated by the buried pipeline received by the receiving coil.

[0061] Among them, since the magnetic field generated by several excitation coils 30 is focused on the buried pipeline, the receiving coil can accurately receive the induced magnetic field generated by the buried pipeline, which helps us to more easily distinguish and quantify the defects of the buried pipeline, thereby improving the accuracy of buried pipeline defect detection.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A buried pipeline defect detection device, comprising a magnetic signal transmitter, a reflection signal receiver (70) and a transient electromagnetic controller, wherein the magnetic signal transmitter is equipped with at least one excitation coil, the reflection signal receiver (70) is equipped with a receiving coil, the excitation coil of the magnetic signal transmitter and the receiving coil of the reflection signal receiver (70) are respectively connected to the transient electromagnetic controller, the magnetic signal transmitter, the reflection signal receiver (70) and the transient electromagnetic controller are all arranged above the buried pipeline, characterized in that: The magnetic signal transmitter is a magnetic focusing mechanism. The magnetic focusing mechanism comprises a chassis (1), the chassis (1) is circular in shape, a fixed shaft (11) is arranged on a center line passing through the center of the chassis (1), a plurality of rotating frame units (2) are arranged on the chassis (1), the rotating frame units (2) are arc-shaped, each of the rotating frame units (2) can slide left and right around the fixed shaft (11), and the plurality of rotating frame units (2) are connected in sequence on the rotation path of the chassis (1) to form a circular arc surface; At least one excitation coil posture adjuster (3) is slidably disposed on each of the rotating frame units (2), an excitation coil (30) is disposed inside each of the excitation coil posture adjusters (3), the excitation coil posture adjuster (3) has a rectangular shape, the excitation coil (30) is a square coil, and the excitation coil (30) can rotate in the excitation coil posture adjuster (3) in the up-down direction and the front-back direction respectively; The excitation coil posture adjuster (3) can slide left and right around the fixed axis (11) along with the rotating frame unit (2) to adjust the position of the excitation coil (30) thereon; the excitation coil posture adjuster (3) can slide up and down on the rotating frame unit (2) to adjust the height of the excitation coil (30); the excitation coil (30) can also adjust the posture of the excitation coil (30) by flipping in the up-down direction and the front-back direction inside the excitation coil posture adjuster (3), so that the excitation coils (30) inside the excitation coil posture adjusters (3) on the rotating frame units (2) meet the condition of magnetic focusing, wherein the condition of magnetic focusing is that the magnetic field excited by the excitation coils (30) is just focused on the buried pipeline.

2. The buried pipeline defect detection device according to claim 1, characterized in that: The excitation coil posture adjuster (3) comprises an outer frame (31), an upper and lower posture adjustment mechanism (41), a middle frame (32), a front and rear posture adjuster (42) and an inner frame (33). The inner frame (33) is a square frame, and the excitation coil (30) is arranged in the inner frame (33); The inner frame (33) is arranged inside the middle frame (32), and a second posture adjustment shaft (420) is arranged between the inner frame (33) and the middle frame (32) as a pivot, and the front and rear posture adjusters (42) are arranged on the second posture adjustment shaft (420); The middle frame (32) is arranged inside the outer frame (31), and a first posture adjustment axis (410) is arranged between the middle frame (32) and the outer frame (31) as a pivot, and the up and down posture adjustment mechanism (41) is arranged on the first posture adjustment axis (410); The first posture adjustment axis (410) and the second posture adjustment axis (420) are perpendicular to each other; Wherein, the up-down posture adjustment mechanism (41) is used to achieve the flipping of the excitation coil (30) in the up-down direction by controlling the rotation of the front-back posture adjuster (42); The front-rear posture adjuster (42) is used to achieve the flipping of the excitation coil (30) in the left-right direction by controlling the rotation of the inner frame (33).

3. The buried pipeline defect detection device according to claim 2, characterized in that: The outer frame (31) comprises a left guide module (311), a right guide module (313), an upper fixing plate (312) and a lower fixing plate (314); the left guide module (311), the upper fixing plate (312), the right guide module (313) and the lower fixing plate (314) are connected end to end in sequence to form the outer frame (31); The first posture adjustment shaft (410) comprises an upper connecting shaft and a lower connecting shaft, and the extension lines of the upper connecting shaft and the lower connecting shaft are located on the same straight line, and together constitute the first posture adjustment shaft (410); the upper side of the middle frame (32) is pivotally connected to the upper fixing plate (312) via the upper connecting shaft of the first posture adjustment shaft (410), and the lower side of the middle frame (32) is pivotally connected to the lower fixing plate (314) via the lower connecting shaft of the first posture adjustment shaft (410), and the upper and lower posture adjustment mechanism (41) is arranged on the lower connecting shaft of the first posture adjustment shaft (410); The second posture adjustment axis (420) comprises a left connecting axis and a right connecting axis, and the extension lines of the left connecting axis and the right connecting axis are located on the same straight line, and together constitute the second posture adjustment axis (420); the left side of the inner frame (33) is pivotally connected to the left side plate of the middle frame (32) via the left connecting axis of the second posture adjustment axis (420), and the right side of the inner frame (33) is pivotally connected to the right side plate of the middle frame (32) via the right connecting axis of the second posture adjustment axis (420), and the front and rear posture adjusters (42) are arranged on the left connecting axis of the second posture adjustment axis (420).

4. The buried pipeline defect detection device according to claim 3, characterized in that: The middle frame (32) and the inner frame (33) are both square frames, and are formed by connecting an upper side plate, a right side plate, a lower side plate and a left side plate end to end in sequence; The upper side plate of the middle frame (32) is pivotally connected to the upper fixed plate (312) via an upper connecting shaft, and the lower side plate of the middle frame (32) is pivotally connected to the lower fixed plate (314) via a lower connecting shaft; the upper and lower posture adjustment mechanism (41) is located in a gap between the lower fixed plate (314) and the lower side plate of the middle frame (32); The left side of the inner frame (33) is pivotally connected to the left side plate of the middle frame (32) via a left connecting shaft, and the right side plate of the inner frame (33) is pivotally connected to the right side wall of the middle frame (32); the front and rear posture adjuster (42) is located in the gap between the left side plate of the middle frame (32) and the left side plate of the inner frame (33).

5. The buried pipeline defect detection device according to claim 3, characterized in that: The up-and-down posture adjustment mechanism (41) and the front-and-rear posture adjustment device (42) both comprise a motor (51), a coupling (52), and a bevel gear set (53). The bevel gear set (53) comprises a driving wheel (531), a left transmission wheel (532), a right transmission wheel (533) and an auxiliary wheel (534); the driving wheel (531), the left transmission wheel (532), the right transmission wheel (533) and the auxiliary wheel (534) are all bevel gears. The left transmission wheel (532) and the right transmission wheel (533) are arranged in pairs on the lower connecting shaft of the first posture adjustment shaft (410) or the left connecting shaft of the second posture adjustment shaft (420); The driving wheel (531) and the auxiliary wheel (534) are arranged in pairs between the left transmission wheel (532) and the right transmission wheel (533), and two ends of the driving wheel (531) are respectively meshed with one end of the left transmission wheel (532) and the right transmission wheel (533), and the other ends of the left transmission wheel (532) and the right transmission wheel (533) are respectively meshed with the auxiliary wheel (534); The output shaft of the motor (51) is fixedly connected to the driving wheel (531) of the bevel gear set (53) via the coupling (52); The left transmission wheel (532) and the right transmission wheel (533) are integrally formed with the lower connecting shaft of the first posture adjustment shaft (410) or the left connecting shaft of the second posture adjustment shaft (420) to form a large gear with a shaft.

6. The buried pipeline defect detection device according to claim 5, characterized in that: The motor (51) is provided with a motor support. The motor support of the up-and-down posture adjustment mechanism (41) is arranged on the inner side of the lower fixing plate (314); The motor support of the front and rear posture adjuster (42) is arranged on the inner side of the left side plate of the middle frame (32); The driving wheel (531) is provided with a driving wheel support. The driving wheel support of the up-and-down posture adjustment mechanism (41) is arranged on the inner side of the lower fixing plate (314); The driving wheel support of the front and rear posture adjuster (42) is arranged on the inner side of the left side plate of the middle frame (32); The auxiliary wheel (534) is provided with an auxiliary wheel support. The auxiliary wheel support of the up-and-down posture adjustment mechanism (41) is arranged on the inner side of the lower fixing plate (314); The auxiliary wheel support of the front and rear posture adjuster (42) is arranged on the inner side of the left side plate of the middle frame (32); The left transmission wheel (532) and the right transmission wheel (533) of the up-and-down posture adjustment mechanism (41) are arranged in pairs on the lower connecting shaft of the first posture adjustment shaft (410); The left transmission wheel (532) and the right transmission wheel (533) of the up and down posture adjustment mechanism (41) are arranged in pairs on the left connecting shaft of the second posture adjustment shaft (420).

7. The buried pipeline defect detection device according to claim 1, characterized in that: A support frame (10) is arranged at the center of the chassis (1), and the fixed shaft (11) is arranged on the support frame (10); The outer ring of the chassis (1) is equally divided into four parts, and an arc-shaped slide rail (12) is provided on the outer ring of each part; Four rotating frame units (2) are arranged on the chassis (1), and each rotating frame unit (2) is provided with a pivot hole (23) at the top end and a slider assembly (22) at the bottom end; The pivot hole (23) of the rotating frame unit (2) is penetrated on the fixed shaft (11), and the slider assemblies (22) of the four rotating frame units (2) are respectively arranged on the four arc-shaped slide rails (12) of the outer ring of the chassis (1).

8. The buried pipeline defect detection device according to claim 7, characterized in that: An excitation coil posture adjuster (3) is respectively provided at the upper and lower parts of the two arc-shaped rods (21) of each rotating frame unit (2). The upper parts of the four rotating frame units (2) form four excitation coil posture adjusters (3) located thereon, and the four excitation coil posture adjusters (3) located thereon are of the same height; The lower parts of the four rotating frame units (2) form four excitation coil posture adjusters (3) located thereunder, and the four excitation coil posture adjusters (3) located thereunder are of the same height.

9. The buried pipeline defect detection device according to claim 3, characterized in that: The rotating frame unit (2) comprises two arc-shaped rods (21) and a transverse plate (20), the top ends of the two arc-shaped rods (21) are connected together via the transverse plate (20), the slider assembly (22) is respectively arranged at the bottom ends of the two arc-shaped rods (21), and the pivot hole (23) is arranged at the top end of the transverse plate (20) of the rotating frame unit (2); The left guide module (311) and the right guide module (313) on both sides of the outer frame (31) are respectively arranged on the arc-shaped rods (21) on both sides of the rotating frame unit (2).

10. The buried pipeline defect detection device according to claim 9, characterized in that: The left guide module (311) and the right guide module (313) are both provided with side panels, and the side panels of the left guide module (311) and the right guide module (313) are connected to the arc-shaped rod (21) of the rotating frame unit (2) via a sliding pre-tightening mechanism. The sliding pre-tightening mechanism comprises a first upper guide wheel (61), a second upper guide wheel (62), a first lower guide wheel (63), a pair of pre-tightening springs (64) and two pairs of clamping plates (65). The top and bottom surfaces of the arc-shaped rod (21) of the rotating frame unit (2) are respectively provided with sliding grooves, the first upper guide wheel (61) and the second upper guide wheel (62) are respectively arranged in the sliding grooves on the top surface of the arc-shaped rod (21), and the first lower guide wheel (63) is arranged in the sliding grooves on the bottom surface of the arc-shaped rod (21), and the first upper guide wheel (61), the second upper guide wheel (62), and the first lower guide wheel (63) are respectively penetrated by screws, and the screws pass through the side panels of the left guide module (311) and the right guide module (313), and nuts are respectively arranged at both ends of each screw, and the side panels of the left guide module (311) or the right guide module (313) are locked with the arc-shaped rod (21) of the rotating frame unit (2) by tightening the nuts at both ends of the screws; Three support columns (640) are respectively arranged on the side panels of the left guide module (311) and the right guide module (313) opposite to the screw rods of the first upper guide wheel (61), the second upper guide wheel (62) and the first lower guide wheel (63), and each support column (640) and its corresponding screw rod are pre-tightened by a pair of pre-tightening springs (64) located on both sides of the arc rod (21); A pair of bolts are disposed transversely between the side panels of the left guide module (311) and the right guide module (313) and the arc-shaped rod (21) of the rotating frame unit (2); clamping plates (65) and nuts are respectively passed through the bolts; by tightening the nuts and pushing the clamping plates (65), the side panels of the left guide module (311) or the right guide module (313) are pressed against the arc-shaped rod (21) of the rotating frame unit (2).

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