Symmetrical differential magnetic focusing probe for detecting pipeline without removing coating and implementation method thereof

Abstract

The application discloses a symmetrical differential magnetic focusing probe for detecting pipeline without unpacking coating and a realization method, which comprises a support frame; the support frame is provided with an upper differential magnetic sensor assembly, a first silicon steel sheet assembly, a first excitation coil assembly, a zero magnetic flux point sensor assembly, a second excitation coil assembly, a second silicon steel sheet assembly and a lower differential magnetic sensor assembly from top to bottom; a sliding part is arranged at the lowermost end of the support frame; the first and second excitation coil assemblies are adjusted in position by a lifting mechanism and a fine adjustment mechanism to determine a zero magnetic flux surface and a zero magnetic flux point; the zero magnetic flux point sensor assembly is arranged on the zero magnetic flux point; the upper and lower differential magnetic sensor assemblies and the first and second silicon steel sheet assemblies are symmetrically arranged on the zero magnetic flux surface; and the upper and lower differential magnetic sensor assemblies and the zero magnetic flux point sensor assembly are connected with a signal processing system. The application has the advantages of long detection distance, high sensitivity, simple operation, good penetration and the like, and realizes the detection and positioning of defects of a steel pipeline.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline damage detection, in particular to a symmetric differential magnetic focusing probe for detecting a pipeline without removing the coating layer and an implementation method thereof. BACKGROUND

[0002] In the harmonic magnetic field detection steel pipeline technology, the harmonic excitation source is composed of low-frequency signals and high-frequency signals, which takes into account the characteristics of long propagation distance and strong penetration of low-frequency signals and high sensitivity and sensitivity to small defects of high-frequency signals, and has good application in buried steel pipeline, coated steel pipeline and underground comprehensive pipeline defect detection. However, there are still problems in the detection process, such as the judgment of defect information caused by the interference of excitation magnetic field to induced magnetic field, the difficulty in extracting induced magnetic field signal and the short detection distance.

[0003] The existing patent A (CN112730599A) discloses a buried pipeline damage harmonic magnetic field detection system and implementation method based on FPGA, and specifically proposes a software data processing method, but a complex algorithm program is needed to realize the effective extraction of the induced magnetic field; the existing patent B (CN112730598A) discloses a buried steel pipeline non-excavation harmonic magnetic field focusing detection probe manufacturing method, and specifically proposes a method of using electromagnetic shielding film to exclude external interference, but this method cannot solve the problem of interference of excitation magnetic field to induced magnetic field, therefore, there is an urgent need for a symmetric differential magnetic focusing probe for detecting a pipeline without removing the coating layer, which has strong magnetic field signal, high sensitivity, simple operation and good penetration. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a symmetric differential magnetic focusing probe for detecting a pipeline without removing the coating layer and an implementation method thereof, which can detect defects in a steel pipeline in service without removing the coating layer, can focus the magnetic field, can offset the influence of the excitation magnetic field on defect judgment, and can collect the induced magnetic field containing pipeline information without excitation magnetic field interference, has the advantages of simple operation, convenient adjustment and the like, and can meet the actual engineering detection requirements.

[0005] The present application discloses a symmetric differential magnetic focusing probe for detecting a pipeline without removing the coating layer, comprising a support frame;

[0006] An upper differential magnetic sensor assembly, a first silicon steel sheet assembly, a first excitation coil assembly, a zero magnetic flux point sensor assembly, a second excitation coil assembly, a second silicon steel sheet assembly and a lower differential magnetic sensor assembly are sequentially and spacedly installed on the support frame from top to bottom; a sliding member for sliding on the coated pipeline is installed at the lowermost end of the support frame;

[0007] Both the first excitation coil assembly and the second excitation coil assembly include a coil frame and multiple coil rods. The coil frame is mounted on the support frame in a lifting manner via a lifting mechanism. The multiple coil rods are mounted on the coil frame in a lifting manner via a fine-tuning mechanism, and excitation coils are wound on the multiple coil rods. One end of the upper and lower excitation coils is grounded, and the other end is connected to the harmonic excitation source as an input terminal.

[0008] The upper and lower excitation coils are the same in size, shape and number of turns. The positions of the upper and lower excitation coils can be adjusted by the lifting mechanism and the fine-tuning mechanism to determine the zero flux plane and the zero flux point.

[0009] The zero flux point sensor assembly is mounted on the zero flux surface, and the sensor in the zero flux point sensor assembly is mounted on the zero flux point; the upper differential magnetometer assembly, the first silicon steel sheet assembly, the second silicon steel sheet assembly, and the lower differential magnetometer assembly are symmetrically arranged on the upper and lower surfaces of the zero flux surface;

[0010] The sensors in the upper differential magnetometer assembly, the lower differential magnetometer assembly, and the zero flux point sensor assembly are all connected to the signal processing system.

[0011] As a further improvement of the present invention, the support frame includes 4 uprights, 4 crossbars, 4 support rods and 2 tray frames;

[0012] The four columns are arranged in parallel along the vertical direction to form a support frame with a rectangular cross-section;

[0013] The four horizontal support rods and the four support rods are installed symmetrically in pairs at the top and bottom of two adjacent columns to form two flat end faces; the adjacent horizontal support rods and support rods are connected to the columns by means of dougong groove riveting.

[0014] Two pallet frames are symmetrically installed at both ends of the four uprights. Each pallet frame includes a pallet upright, a pallet crossbar, and a pallet cap holder.

[0015] The bottom of each of the four pallet uprights is connected to the top and bottom of the corresponding uprights via the pallet cap seat, and the four pallet crossbars are respectively arranged between two adjacent pallet uprights;

[0016] The upper differential magnetic sensor assembly, the first silicon steel sheet assembly, the lower differential magnetic sensor assembly, and the second silicon steel sheet assembly are respectively fixed on the upper and lower tray columns;

[0017] The bottom end of the lowest tray column is fixedly equipped with the sliding component, which includes a caster wheel.

[0018] As a further improvement of the present application, the coil holder is an "X"-shaped coil holder, four ends of the "X"-shaped coil holder are provided with a hanging sleeve for sleeving on the column of the support frame, and the hanging sleeve is detachably connected with the column.

[0019] The outer side of each hanging sleeve is detachably provided with the fine adjustment mechanism.

[0020] As a further improvement of the present application, the fine adjustment mechanism comprises a sleeve, a fine adjustment screw, a hand rotating adjusting rod, a sleeve cover and a fixing cover.

[0021] A plurality of guide rails are arranged on the inner wall of the sleeve along the axial direction of the sleeve, and an insertion plate is protruded from the outer side of the sleeve for insertion into the hanging sleeve, and the hanging sleeve is provided with an insertion slot corresponding to the insertion plate.

[0022] One end of the sleeve is detachably provided with the sleeve cover and the fixing cover in sequence, and the other end of the sleeve is telescopically provided with the coil rod.

[0023] The coil rod comprises an integrated excitation coil winding column and a base, the base and part of the excitation coil winding column are arranged in the sleeve, and a plurality of guide grooves matched with the guide rails are arranged on the outer side of the base along the axial direction of the base; the end of the excitation coil winding column is protruded from the end of the sleeve by a distance for winding the excitation coil.

[0024] The hand rotating adjusting rod is clamped in the clamping groove of the sleeve cover through a limiting shaft shoulder after passing through the fixing cover.

[0025] One end of the fine adjustment screw is connected with the hand rotating adjusting rod through a reverse thread pair after passing through the coil rod and the sleeve cover, the other end of the fine adjustment screw is protruded from the excitation coil winding column, and the inner wall of the base is provided with an inner thread matched with the fine adjustment screw.

[0026] The other end of the hand rotating adjusting rod is protruded from the fixing cover to serve as a handle part of the fine adjustment mechanism.

[0027] As a further improvement of the present application, the lifting mechanism comprises an adjusting right-angle gear shaft, a right-angle gear screw, a left locking frame, a right locking frame and a fastening strip.

[0028] The right-angle gear shaft is horizontally passed through the reserved hole of the cross rod of the tray frame to be positioned by the shaft shoulder thereof.

[0029] The left locking frame and the right locking frame are both "N"-shaped locking frames, and the two "N"-shaped locking frames are symmetrically arranged, and the two sides of the two "N"-shaped locking frames are hung on the corresponding cross rods.

[0030] The abutting position of the two 'N' shaped locking frames is provided with a semicircular groove, the right angle gear screw rod passes through the semicircular groove and the 'X' shaped coil frame in sequence along the vertical direction, and the intersection of the 'X' shaped coil frame is provided with a threaded hole matched with the right angle gear screw rod;

[0031] The semicircular groove at the abutting position of the two 'N' shaped locking frames clamps the right angle gear screw rod through the fastening strip to limit the freedom degree of movement of the right angle gear screw rod, so that the right angle gear screw rod can only rotate, and the adjusting right angle gear shaft and the right angle gear screw rod are engaged through the bevel gear.

[0032] As a further improvement of the present application, the upper differential magnetic sensor assembly is used to collect excitation magnetic field information, and the lower differential magnetic sensor assembly is used to collect coupling magnetic field signals of the excitation magnetic field and the pipeline induced magnetic field;

[0033] The upper differential magnetic sensor assembly and the lower differential magnetic sensor assembly each include a first high-sensitivity TMR magnetic sensor, a first sensor circuit board and a first 'X' shaped sensor holder;

[0034] The four ends of the first 'X' shaped sensor holder are sleeved on the tray stand column and detachably connected with the tray stand column, the center of the first 'X' shaped sensor holder is detachably provided with the first sensor circuit board, and the first high-sensitivity TMR magnetic sensor is inserted into the first sensor circuit board;

[0035] The upper and lower first high-sensitivity TMR magnetic sensors are connected with the signal processing system through high-speed real-time acquisition cards;

[0036] The distance between the lower differential magnetic sensor assembly and the pipeline to be detected is not greater than 500 mm.

[0037] As a further improvement of the present application, the zero magnetic flux point sensor assembly includes a second high-sensitivity TMR magnetic sensor, a second sensor circuit board and a second 'X' shaped sensor holder;

[0038] The second 'X' shaped sensor holder is installed on the zero magnetic flux surface, the four ends of the second 'X' shaped sensor holder are detachably connected with the stand column of the support frame, and the center of the second 'X' shaped sensor holder is detachably provided with the second sensor circuit board, and the second high-sensitivity TMR magnetic sensor is inserted into the second sensor circuit board;

[0039] The second high-sensitivity TMR magnetic sensor is located at the position of the magnetic field zero magnetic flux point, so as to ensure that the excitation magnetic field has a magnetic field strength of zero at the position, and the induced magnetic field signal containing the pipeline defect information and free from the excitation magnetic field interference can be collected;

[0040] The second high-sensitivity TMR magnetic sensor is connected with the signal processing system through a high-speed real-time acquisition card.

[0041] As a further improvement of the application, the silicon steel sheet assembly comprises a silicon steel sheet and an "X"-shaped silicon steel sheet holder;

[0042] The four ends of the "X"-shaped silicon steel sheet holder are sleeved on the tray stand columns, and the center of the "X"-shaped silicon steel sheet holder is detachably mounted with the silicon steel sheet.

[0043] The application further discloses an implementation method of a symmetric differential magnetic focusing probe for pipeline detection without removing a coating layer, comprising the following steps:

[0044] S1, taking out TMR magnetic sensors from a magnetic shielding barrel, and respectively inserting the sensors into the bases of sensor circuit boards in the upper differential magnetic sensor assembly, the lower differential magnetic sensor assembly and the zero magnetic flux point sensor assembly;

[0045] S2, connecting a harmonic excitation source to the excitation coils of the symmetrically-installed first excitation coil assembly and the second excitation coil assembly of the stand column of the support frame, and connecting a plurality of TMR magnetic sensors with a real-time display acquisition device;

[0046] S3, moving the coil frame with the upper and lower excitation coils by adjusting the lifting mechanism, and observing whether the data collected by the zero magnetic flux point sensor assembly and displayed on the real-time display acquisition device is a data band or a data curve with a narrow range and small values, if not, continue to adjust the lifting mechanism;

[0047] S4, moving the plurality of coil rods to drive the excitation coils to move up and down by adjusting the fine adjustment mechanism, so as to compensate for the difference of the manually-wound coils, and observing whether the zero magnetic flux point sensor data displayed on the real-time display acquisition device is approximately zero;

[0048] S5, after the zero magnetic flux surface and the zero magnetic flux point are determined, adjusting the positions of the upper and lower differential magnetic sensor assemblies and the first and second silicon steel sheet assemblies, and fixing them on the support frame through bolts;

[0049] S6, attaching the sliding member at the bottom of the support frame of the probe to the pipeline coating layer, and starting to scan and detect the pipeline from one end of the pipeline until the scanning ends at the other end, and collecting data in real time during the detection process;

[0050] S7, repeating the above step S6 to scan and detect the pipeline according to different sides of the pipeline, so as to complete the scanning and detection of the entire pipeline;

[0051] S8, analyze the collected experimental data, and difference the coupling magnetic field data and the excitation magnetic field data collected in the upper and lower differential sensor assemblies, and compare with the data collected by the zero flux point sensor assembly;

[0052] S9, after the experiment, the TMR sensor is taken off and put back into the magnetic shielding barrel to avoid the influence of the external environment on the sensor and to avoid inaccurate data collection.

[0053] As a further improvement of the application, in the step S6 and the step S7, the scanning detection times for each side of the cladding pipe are not less than 3 times.

[0054] Compared with the prior art, the application has the following beneficial effects:

[0055] The application has the advantages of simple structure, convenient operation, damage detection of steel pipes with different thickness claddings in service, avoidance of economic loss caused by equipment shutdown and cladding removal, and prevention of damage to the pipe caused by cladding removal.

[0056] The application can change the positions of the upper and lower excitation coils by adjusting the lifting mechanism, so that the zero flux point is generated, the sensor in the zero flux point sensor assembly can collect the induced magnetic field containing pipe defect information and free from excitation magnetic field interference, and the fine adjustment structure in the application can adjust the upper and lower excitation coils by lifting and avoiding rotation, so as to compensate for the manufacturing error of the upper and lower excitation coils and improve the sensitivity of the probe.

[0057] The upper differential magnetic sensor assembly in the application is used for collecting excitation magnetic field information, and the lower differential magnetic sensor assembly is used for collecting coupling magnetic field signals of the excitation magnetic field and the pipe induced magnetic field, so that the interference of the excitation magnetic field on the pipe defect information judgment can be offset after the two signals are differentiated.

[0058] The first silicon steel sheet assembly and the second silicon steel sheet assembly in the application can focus the magnetic field and enhance the magnetic field signal, and at the same time, the silicon steel sheet form can avoid the generation of eddy current pollution magnetic field, which affects the measurement result and improves the accuracy of the measurement result. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 The structure diagram of the symmetric differential magnetic focusing probe for cladding pipe detection without disassembly disclosed by an embodiment of the application is shown in the figure.

[0060] Figure 2 The structure diagram of the support frame of the symmetric differential magnetic focusing probe for cladding pipe detection without disassembly disclosed by an embodiment of the application is shown in the figure.

[0061] Figure 3The structural diagram of the first and second excitation coil assemblies and the lifting mechanism of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0062] Figure 4 The structural diagram of the left and right locking frames of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0063] Figure 5 The structural diagram of the fine adjustment mechanism of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0064] Figure 6 The structural diagram of the coil frame of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0065] Figure 7 The structural diagram of the upper and lower differential magnetic sensor assemblies of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0066] Figure 8 The structural diagram of the zero magnetic flux point sensor assembly of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0067] Figure 9 The structural diagram of the first and second silicon steel sheet assemblies of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0068] Figure 10 The schematic diagram of the pipeline detection of the probe of the symmetrical differential magnetic focusing probe for detecting the pipeline without unpacking the coating is disclosed for an embodiment of the present application.

[0069] 1, support frame; 1-1, vertical column; 1-2, horizontal rack rod; 1-3, support rod; 1-4, tray frame; 1-41, tray cap seat; 1-42, tray vertical column; 1-43, tray horizontal rod; 2-1, first excitation coil assembly; 2-2, second excitation coil assembly; 3, zero flux point sensor assembly; 4-1, upper differential magnetic sensor assembly; 4-2, lower differential magnetic sensor assembly; 5-1, first silicon steel sheet assembly; 5-2, second silicon steel sheet assembly; 6, lifting mechanism; 6-1, right angle gear shaft; 6-2, right angle gear screw; 6-3, left and right locking frame; 6-31, notch; 6-32, semicircular groove; 6-4, fastening strip; 7, fine adjustment mechanism; 7-1, sleeve; 7-11, guide rail; 7-12, plug plate; 7-2, sleeve cover; 7-3, fixed cover; 7-4, hand rotating adjustment rod; 7-41, limiting shaft shoulder; 7-5, fine adjustment screw; 8, universal wheel; 9-1, first "X" shaped sensor holder; 9-2, second "X" shaped sensor holder; 10-1, first sensor circuit board; 10-2, second sensor circuit board; 11-1, first high sensitivity TMR magnetic sensor; 11-2, second high sensitivity TMR magnetic sensor; 12, "X" shaped silicon steel sheet holder; 13, silicon steel sheet; 14, "X" shaped coil holder; 14-1, threaded through hole; 15, coil rod; 15-1, base; 15-2, excitation coil winding column; 16, hanging sleeve; 16-1, insertion slot; 17, pipe; 18, cladding layer. DETAILED DESCRIPTION

[0070] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of the present application.

[0071] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance.

[0072] In the description of the present application, it is also necessary to explain that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0073] The present application will be further described in detail below with reference to the accompanying drawings:

[0074] As shown in Figures 1-9 The present application provides a symmetrical differential magnetic focusing probe for detecting coated pipe without disassembly, comprising a support frame 1; an upper differential magnetic sensor assembly 4-1, a first silicon steel sheet assembly 5-1, a first excitation coil assembly 2-1, a zero flux point sensor assembly 3, a second excitation coil assembly 2-2, a second silicon steel sheet assembly 5-2 and a lower differential magnetic sensor assembly 4-2 are sequentially and spacedly mounted on the support frame 1 from top to bottom; a sliding member for sliding on the coated pipe 18 is mounted at the lowermost end of the support frame 1; the first excitation coil assembly 2-1 and the second excitation coil assembly 2-2 each comprise a coil frame and a plurality of coil rods 15, the coil frame is mounted on the support frame 1 by a lifting mechanism 6, the plurality of coil rods 15 are mounted on the coil frame by a fine adjustment mechanism 7, and the plurality of coil rods 15 are wound with excitation coils, one end of the upper and lower excitation coils is grounded, and the other end is connected with a harmonic excitation source as an input terminal;

[0075] The size, shape and number of turns of the upper and lower excitation coils are the same, the position of the upper and lower excitation coils can be adjusted by the lifting mechanism 6 and the fine adjustment mechanism 7 to determine the zero flux plane and the zero flux point; the zero flux point sensor assembly 3 is installed on the zero flux plane, and the sensors in the zero flux point sensor assembly 3 are installed on the zero flux point; the upper differential magnetic sensor assembly 4-1, the first silicon steel sheet assembly 5-1 and the second silicon steel sheet assembly 5-2, and the lower differential magnetic sensor assembly 4-2 are symmetrically arranged above and below the zero flux plane; the sensors in the upper differential magnetic sensor assembly 4-1, the lower differential magnetic sensor assembly 4-2 and the zero flux point sensor assembly 3 are connected with a signal processing system.

[0076] Specifically:

[0077] As shown in Figures 1-2As shown, the support frame 1 in the present application comprises 4 vertical columns 1-1, 4 horizontal frame rods 1-2, 4 support rods 1-3 and 2 tray frames 1-4; the 4 vertical columns 1-1 are arranged in parallel in the vertical direction to form a support frame 1 with a rectangular cross section; the 4 horizontal frame rods 1-2 and the 4 support rods 1-3 are respectively installed at the top and bottom ends of the adjacent 2 vertical columns 1-1 in a two-by-two symmetrical manner to form two flat end faces; the adjacent horizontal frame rods 1-2 and support rods 1-3 are connected with the vertical columns 1-1 in a corbel slot riveting manner; and the 2 tray frames 1-4 are respectively symmetrically installed at the two ends of the 4 vertical columns 1-1.

[0078] Further, the tray frame 1-4 in the present application comprises a tray vertical column 1-42, a tray horizontal rod 1-43 and a tray cap seat 1-41; the bottom of the 4 tray vertical columns 1-42 is sleeved on the top and bottom ends of the corresponding vertical columns 1-1 through the tray cap seat 1-41, and the 4 tray horizontal rods 1-43 are respectively arranged between the adjacent 2 tray vertical columns 1-42; the upper differential magnetic sensor assembly 4-1 and the first silicon steel sheet assembly 5-1 and the lower differential magnetic sensor assembly 4-2 and the second silicon steel sheet assembly 5-2 are respectively fixed on the upper and lower tray vertical columns 1-42; the bottom end of the lowermost tray vertical column 1-42 is fixedly installed with a sliding member, and the sliding member comprises one of a universal wheel 8 and a ball.

[0079] As shown in Figure 3 , 4 , 6, the coil frame in the present application is an "X" shaped coil frame 14, and the four ends of the "X" shaped coil frame 14 are each installed with a hanging sleeve 16 for sleeving on the vertical column 1-1 of the support frame 1, and the hanging sleeve 16 is detachably connected with the vertical column 1-1, and the outer side of each hanging sleeve 16 is each detachably installed with a fine adjustment mechanism 7.

[0080] Further, the lifting mechanism 6 in the application comprises an adjusting right-angle gear shaft 6-1, a right-angle gear screw 6-2, a left locking frame 6-3, a right locking frame 6-3, and a fastening strip 6-4; the right-angle gear shaft 6-1 horizontally passes through the reserved hole of the tray horizontal rod 1-43 of the tray frame to be positioned by the shaft shoulder thereof; the left locking frame 6-3 and the right locking frame 6-3 are both "R" type locking frames 6-3, and the two "R" type locking frames 6-3 are symmetrically installed, and the two "R" type locking frames 6-3 are provided with notches 6-31 for being hung on the corresponding horizontal frame rods; the abutting portions of the two "R" type locking frames 6-3 are both provided with semicircular grooves 6-32, the right-angle gear screw 6-2 sequentially passes through the semicircular grooves 6-32 and the "X" type coil frame 14 in the vertical direction, and the intersection of the "X" type coil frame 14 is provided with a threaded hole 14-1 matched with the right-angle gear screw 6-2; the semicircular grooves 6-32 of the abutting portions of the two "R" type locking frames 6-3 clamp the right-angle gear screw 6-2 through the fastening strip 6-4 to limit the freedom degree of movement thereof, so that the right-angle gear screw 6-2 can only rotate, the adjusting right-angle gear shaft 6-1 and the right-angle gear screw 6-2 are engaged by the conical gears, the right-angle gear screw 6-2 in the application adopts two-section shaft shoulders to position the clamping positions of the left and right locking frames 6-3 at the semicircular grooves 6-32, and the end of the right-angle gear screw 6-2 is a screw structure.

[0081] As shown in the figure, Figure 5 the fine adjustment mechanism 7 in the application comprises a sleeve 7-1, a fine adjustment screw 7-5, a hand rotation adjusting rod 7-4, a sleeve cover 7-2, and a fixed cover 7-3; a plurality of guide rails are arranged on the inner wall of the sleeve 7-1 along the sleeve axial direction, the outer side of the sleeve 7-1 extends a plug plate 7-12 for being inserted into the hanging sleeve 16, the hanging sleeve 16 is provided with a plug groove 16-1 corresponding to the plug plate 7-12; the sleeve 7-1 is detachably installed with the sleeve cover 7-2 and the fixed cover 7-3 in sequence at one end thereof, and the sleeve 7-1 is telescopically installed with the coil rod 15 at the other end thereof.

[0082] Further, the coil rod 15 in the application comprises an integrated excitation coil winding column 15-2 and a base 15-1, the base 15-1 and part of the excitation coil winding column 15-2 are arranged in the sleeve 7-1, the outer side of the base 15-1 is provided with a plurality of guide grooves matched with the guide rails 7-11 along the axial direction of the base 15-1; the end of the excitation coil winding column 15-2 extends out of the end of the sleeve 7-1 by a distance to provide a winding space for the excitation coil; one end of the hand rotation adjusting rod 7-4 passes through the fixed cover 7-3 and is clamped in the clamping groove of the sleeve cover 7-2 by the limiting shaft shoulder 7-41;

[0083] Further, one end of the fine adjustment screw rod 7-5 in the application passes through the coil rod 15 and the sleeve cover 7-2 and is connected with the hand rotation adjusting rod 7-4 through a reverse thread pair, the other end of the fine adjustment screw rod 7-5 extends out of the coil winding column 15-2, and the inner wall of the base 15-1 is provided with an inner thread matched with the fine adjustment screw rod 7-5; the center of the coil rod 15 is provided with an inner threaded hole matched with the fine adjustment screw rod 7-5 for lifting movement; the other end of the hand rotation adjusting rod 7-4 extends out of the fixed cover 7-3 to serve as a handle part of the fine adjustment mechanism. The fine adjustment mechanism 7 in the application can compensate for the manufacturing difference of the symmetrical excitation coil by more flexible adjustment of the coil position, and ensure the probe sensitivity.

[0084] In use, the hand rotation adjusting rod 7-4 is rotated to drive the fine adjustment screw rod 7-5 to rotate, the base 15-1 of the coil rod 15 is matched with the fine adjustment screw rod through an inner threaded hole to rotate, and then the coil rod 15 moves forward and backward in the sleeve 7-1 to drive the upper and lower excitation coils to be fine adjusted, so as to compensate for the manufacturing error of the upper and lower excitation coils and improve the sensitivity of the probe.

[0085] Further, in the upper and lower differential magnetic sensor assemblies in the application, the excitation coils are loaded with harmonic signals of equal size and opposite direction, so that a zero magnetic flux point is generated in space, which facilitates the positioning and installation of the subsequent zero magnetic flux sensor assembly 3, so as to ensure that the excitation magnetic field has a magnetic field strength of zero at this position and can collect an induced magnetic field signal containing pipeline defect information and without excitation magnetic field interference.

[0086] As shown in the drawings, Figure 7 The upper differential magnetic sensor assembly 4-1 in the application is used for collecting excitation magnetic field information, and the lower differential magnetic sensor assembly 4-2 is used for collecting a coupling magnetic field signal of the excitation magnetic field and the pipeline induced magnetic field; the upper differential magnetic sensor assembly 4-1 and the lower differential magnetic sensor assembly 4-2 each include a first high-sensitivity TMR magnetic sensor 11-1, a first sensor circuit board 10-1 and a first "X"-shaped sensor holder 9-1; the four ends of the first "X"-shaped sensor holder 9-1 are sleeved on the tray column 1-42 and are detachably connected with the tray column 1-42, the center of the first "X"-shaped sensor holder 9-1 is detachably installed with the first sensor circuit board 10-1, and the first sensor circuit board 10-1 is inserted with the first high-sensitivity TMR magnetic sensor 11-1; the upper and lower first high-sensitivity TMR magnetic sensors 11-1 are connected with a signal processing system through a high-speed real-time acquisition card;

[0087] Further, the distance between the lower differential magnetic sensor assembly 4-2 in the application and the pipeline 17 to be measured is not greater than 500 mm.

[0088] As shown in the drawings, Figure 8As shown, the zero flux point sensor assembly 3 in the application comprises a second high-sensitivity TMR magnetic sensor 11-2, a second sensor circuit board 10-2 and a second "X"-shaped sensor holder 9-2; the second "X"-shaped sensor holder 9-2 is installed on the zero flux surface, four ends of the second "X"-shaped sensor holder 9-2 are detachably connected to the column 1-1 of the support frame 1, the center of the second "X"-shaped sensor holder 9-2 is detachably installed with the second sensor circuit board 10-2, and the second high-sensitivity TMR magnetic sensor 11-2 is inserted into the second sensor circuit board 10-2.

[0089] Further, the second high-sensitivity TMR magnetic sensor 11-2 in the application is located at the position of the magnetic field zero flux point, which ensures that the excitation magnetic field has a zero magnetic field strength at this position, and can collect the induced magnetic field signal containing the defect information of the pipeline 17 without the interference of the excitation magnetic field; the second high-sensitivity TMR magnetic sensor 11-2 is connected to the signal processing system through a high-speed real-time acquisition card.

[0090] As shown in the drawings, Figure 9 The silicon steel sheet assembly in the application comprises a silicon steel sheet 13 and an "X"-shaped silicon steel sheet holder 12; four ends of the "X"-shaped silicon steel sheet holder 12 are sleeved on the tray column 1-42, and the center of the "X"-shaped silicon steel sheet holder 12 is detachably installed with the silicon steel sheet 13; the number of the silicon steel sheet 13 in the application is at least two groups.

[0091] Further, all the detachable connections in the application are connected by non-magnetic material bolts, and the upper and lower first "X"-shaped sensor holders 9-1, the second "X"-shaped sensor holder 9-2, the "X"-shaped silicon steel sheet holder 12, the lifting mechanism 6, the fine adjustment mechanism 7 and the support frame 1 in the application are all made of non-magnetic material, which ensures the accuracy of the probe detection result.

[0092] As shown in the drawings, Figure 10 The application further discloses an implementation method of a symmetric differential magnetic focusing probe for detecting a pipeline without removing a coating layer, and the implementation method comprises the following steps:

[0093] S1, taking out TMR magnetic sensors from a magnetic shielding barrel, and inserting the TMR magnetic sensors into the bases of the sensor circuit boards in the upper differential magnetic sensor assembly 4-1, the lower differential magnetic sensor assembly 4-2 and the zero flux point sensor assembly 3 respectively;

[0094] S2, connecting a harmonic excitation source to the excitation coils of the symmetrically installed first excitation coil assembly 2-1 and second excitation coil assembly 2-2 of the column 1-1 of the support frame 1, and connecting the plurality of TMR magnetic sensors to a real-time display acquisition device;

[0095] S3, by adjusting the lifting mechanism 6, the "X" coil holder 14 moves with the upper and lower excitation coils, and whether the data collected by the zero flux point sensor assembly 3 displayed in real time on the real-time display acquisition device is a narrow range and small value data band or data curve is observed, if not, continue to adjust the lifting mechanism 6;

[0096] S4, by adjusting the fine adjustment mechanism 7, the plurality of coil rods 15 are lifted and moved to drive the excitation coils to move up and down, and the difference of manual winding coils is compensated. Whether the zero flux point sensor data displayed in real time on the real-time display acquisition device is approximately zero is observed;

[0097] S5, after the zero flux surface and the zero flux point are determined, the positions of the upper and lower differential magnetic sensor assemblies and the first and second silicon steel sheet assemblies are adjusted, and are fixed on the support frame 1 through bolts;

[0098] S6, the sliding member at the bottom of the support frame 1 of the probe is attached to the cladding layer 18 of the pipeline 17, and the pipeline 17 is scanned and detected from one end of the pipeline 17 to the other end, and the acquisition device collects in real time during the detection process;

[0099] S7, the probe is repeatedly scanned and detected according to the different sides of the pipeline 17 according to the above step S6 to complete the scanning and detection of the entire pipeline 17;

[0100] S8, analyze the collected experimental data, and difference the coupled magnetic field data and the excitation magnetic field data collected in the upper and lower differential sensor assemblies, and compare with the data collected by the zero flux point sensor assembly 3;

[0101] S9, after the experiment is finished, the TMR sensor is taken off and put back into the magnetic shielding barrel to avoid the influence of the external environment on the sensor and to avoid inaccurate data collection.

[0102] Further, in the steps S6 and S7, the scanning and detection times of each side of the cladding layer pipeline 17 are not less than 3 times.

[0103] The beneficial effects of the present application are:

[0104] The present application has the advantages of simple structure, convenient operation, and can detect the damage of the steel pipeline 17 under the cladding layer 18 of different thicknesses in service, avoid the economic loss of equipment downtime and removal of the cladding layer, and prevent the damage of the pipeline 17 caused by removal of the cladding layer 18;

[0105] The present application can change the position of the upper and lower excitation coils by adjusting the lifting mechanism 6, so that the zero flux point is generated, the sensor in the zero flux point sensor assembly 3 can collect the induced magnetic field containing the pipeline defect information and without the interference of the excitation magnetic field, and the fine adjustment structure 7 in the present application can adjust the upper and lower excitation coils in a flexible way by lifting itself and avoiding rotation, so as to compensate for the manufacturing error of the upper and lower excitation coils and improve the sensitivity of the probe.

[0106] The upper differential magnetic sensor assembly 4-1 in the present application is used for collecting excitation magnetic field information, and the lower differential magnetic sensor assembly 4-2 is used for collecting the coupling magnetic field signal of the excitation magnetic field and the pipeline induced magnetic field, so that the interference of the excitation magnetic field on the pipeline defect information judgment can be offset after the two signals are differentiated;

[0107] The first silicon steel sheet assembly 5-1 and the second silicon steel sheet assembly 5-2 in the present application can focus the magnetic field and enhance the magnetic field signal, and at the same time, the silicon steel sheet 13 can avoid generating eddy current pollution magnetic field and affecting the measurement result, so as to improve the accuracy of the measurement result.

[0108] The above is only the preferred embodiment of the present application and is not used to limit the present application, and for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer casing, characterized in that, Including support frame; The support frame is provided with, from top to bottom, an upper differential magnetic sensor assembly, a first silicon steel sheet assembly, a first excitation coil assembly, a zero flux point sensor assembly, a second excitation coil assembly, a second silicon steel sheet assembly, and a lower differential magnetic sensor assembly; a sliding element for sliding on the cladding pipe is installed at the bottom of the support frame. Both the first excitation coil assembly and the second excitation coil assembly include a coil frame and multiple coil rods. The coil frame is mounted on the support frame in a lifting manner via a lifting mechanism. The multiple coil rods are mounted on the coil frame in a lifting manner via a fine-tuning mechanism, and excitation coils are wound on the multiple coil rods. One end of the upper and lower excitation coils is grounded, and the other end is connected to the harmonic excitation source as an input terminal. The upper and lower excitation coils are the same in size, shape and number of turns. The positions of the upper and lower excitation coils can be adjusted by the lifting mechanism and the fine-tuning mechanism to determine the zero flux plane and the zero flux point. The zero flux point sensor assembly is mounted on the zero flux surface, and the sensor in the zero flux point sensor assembly is mounted on the zero flux point; the upper differential magnetometer assembly, the first silicon steel sheet assembly, the second silicon steel sheet assembly, and the lower differential magnetometer assembly are symmetrically arranged on the upper and lower surfaces of the zero flux surface; The sensors in the upper differential magnetometer assembly, the lower differential magnetometer assembly, and the zero flux point sensor assembly are all connected to the signal processing system.

2. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 1, characterized in that, The support frame includes 4 uprights, 4 horizontal bars, 4 support rods, and 2 tray frames; The four columns are arranged in parallel along the vertical direction to form a support frame with a rectangular cross-section; The four horizontal support rods and the four support rods are installed symmetrically in pairs at the top and bottom of two adjacent columns to form two flat end faces; the adjacent horizontal support rods and support rods are connected to the columns by means of dougong groove riveting. Two pallet frames are symmetrically installed at both ends of the four uprights. Each pallet frame includes a pallet upright, a pallet crossbar, and a pallet cap holder. The bottom of each of the four pallet uprights is connected to the top and bottom of the corresponding uprights via the pallet cap seat, and the four pallet crossbars are respectively arranged between two adjacent pallet uprights; The upper differential magnetic sensor assembly, the first silicon steel sheet assembly, the lower differential magnetic sensor assembly, and the second silicon steel sheet assembly are respectively fixed on the upper and lower tray columns; The bottom end of the lowest tray column is fixedly equipped with the sliding component, which includes a caster wheel.

3. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 2, characterized in that, The coil frame is an "X" shaped coil frame, and each of the four ends of the "X" shaped coil frame is equipped with a hanging sleeve for fitting onto the column of the support frame. The hanging sleeve is detachably connected to the column, and the fine-tuning mechanism can be installed on the outside of each hanging sleeve in a removable manner.

4. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 3, characterized in that, The fine-tuning mechanism includes a sleeve, a fine-tuning screw, a hand-rotating adjustment rod, a sleeve cover, and a fixed cover; The inner wall of the sleeve is provided with multiple guide rails along the sleeve axis, and the outer side of the sleeve extends out a plate for inserting the hanging sleeve. The hanging sleeve is provided with a slot corresponding to the plate. One end of the sleeve is detachably installed with the sleeve cover and the fixed cover in sequence, and the other end of the sleeve is telescopically installed with the coil rod; The coil rod includes an excitation coil winding column and a base integrally connected. The base and part of the excitation coil winding column are placed inside the sleeve. A plurality of guide grooves cooperating with the guide rails are provided on the outer side of the base along the axial direction of the base; the end of the excitation coil winding column extends out of the end of the sleeve for a certain distance for winding the excitation coil; One end of the hand-rotating adjusting rod passes through the fixed cover and is stuck in the card slot of the sleeve cover through a limiting shoulder; One end of the fine-tuning screw passes through the coil rod and the sleeve cover and is connected with the hand-rotating adjusting rod through a reverse thread pair. The other end of the fine-tuning screw extends out of the excitation coil winding column, and an internal thread cooperating with the fine-tuning screw is provided on the inner wall of the base; The other end of the hand-rotating adjusting rod extends out of the fixed cover to serve as the handle part of the fine-tuning mechanism.

5. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 3, characterized in that, The lifting mechanism includes an adjusting right-angle gear shaft, a right-angle gear screw, a left locking frame, a right locking frame, and a fastening strip; The right-angle gear shaft horizontally passes through the reserved hole of the cross bar of the tray frame and is positioned by its own shoulder; Both the left locking frame and the right locking frame are "丄”-shaped locking frames. The two "丄”-shaped locking frames are symmetrically installed, and the two sides of the two "丄”-shaped are hung on the corresponding cross bars; Semicircular grooves are provided at the docking places of the two "丄”-shaped locking frames. The right-angle gear screw sequentially passes through the semicircular grooves and the "X”-shaped coil frame in the vertical direction. A threaded through hole cooperating with the right-angle gear screw is provided at the intersection of the "X”-shaped coil frame; The semicircular grooves at the docking places of the two "丄”-shaped locking frames clamp the right-angle gear screw through the fastening strip to limit its freedom of movement, making it only rotatable. The adjusting right-angle gear shaft and the right-angle gear screw are engaged through bevel gears.

6. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 2, characterized in that, The upper differential type magnetic sensor assembly is used to collect excitation magnetic field information, and the lower differential type magnetic sensor assembly is used to collect the coupled magnetic field signal of the excitation magnetic field and the pipeline induction magnetic field; Both the upper differential type magnetic sensor assembly and the lower differential type magnetic sensor assembly include a first high-sensitivity TMR magnetic sensor, a first sensor circuit board, and a first "X”-shaped sensor support; The four ends of the first "X”-shaped sensor support are sleeved on the tray columns and are detachably connected to the tray columns. The first sensor circuit board is detachably installed at the center of the first "X”-shaped sensor support, and the first high-sensitivity TMR magnetic sensor is plugged on the first sensor circuit board; The upper and lower first high-sensitivity TMR magnetic sensors are both connected to the signal processing system through a high-speed real-time acquisition card; The distance between the lower differential type magnetic sensor assembly and the pipeline to be measured is not greater than 500 mm.

7. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 2, characterized in that, The zero-flux point sensor assembly includes a second high-sensitivity TMR magnetic sensor, a second sensor circuit board, and a second "X”-shaped sensor support; The second "X"-shaped sensor holder is mounted on the zero magnetic flux surface. The four ends of the second "X"-shaped sensor holder are detachably connected to the columns of the support frame. The second sensor circuit board is detachably mounted in the center of the second "X"-shaped sensor holder. The second high-sensitivity TMR magnetic sensor is inserted into the second sensor circuit board. The second high-sensitivity TMR magnetic sensor is located at the zero magnetic flux point, ensuring that the magnetic field strength of the excitation magnetic field is zero at this point, and can collect the induced magnetic field signal containing pipeline defect information without interference from the excitation magnetic field. The second high-sensitivity TMR magnetic sensor is connected to the signal processing system via a high-speed real-time acquisition card.

8. The symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in claim 2, characterized in that, The silicon steel sheet assembly includes silicon steel sheets and an "X"-shaped silicon steel sheet holder; The four ends of the "X"-shaped silicon steel sheet holder are sleeved on the tray column, and the silicon steel sheet is detachably installed in the center of the "X"-shaped silicon steel sheet holder.

9. A method for implementing a symmetrical differential magnetic focusing probe for pipeline inspection without removing the outer coating as described in any one of claims 1-8, characterized in that, include: S1. Take the TMR magnetic sensor out of the magnetic shielding barrel and insert it into the base of the sensor circuit board in the upper differential magnetic sensor assembly, the lower differential magnetic sensor assembly and the zero flux point sensor assembly respectively. S2. Connect a harmonic excitation source to the excitation coils of the first excitation coil assembly and the second excitation coil assembly, which are symmetrically installed on the columns of the support frame, and connect multiple TMR magnetic sensors to a real-time display and acquisition device. S3. By adjusting the lifting mechanism, the coil frame moves with the upper and lower excitation coils. Observe whether the data collected by the zero flux point sensor component displayed in real time on the real-time display acquisition device is a data band or data curve with a narrow range and small value. If not, continue to adjust the lifting mechanism. S4. By adjusting the fine-tuning mechanism, multiple coil rods are raised and lowered to drive the excitation coil to rise and fall, thus compensating for the differences in manually wound coils. Observe whether the zero flux point sensor data displayed in real time on the real-time display acquisition device is approximately zero. S5. After the zero flux plane and zero flux point are determined, adjust the positions of the upper and lower differential magnetic sensor assemblies and the first and second silicon steel sheet assemblies, and fix them to the support frame with bolts. S6. Attach the sliding part at the bottom of the support frame of the probe to the pipe covering layer, and start scanning the pipe from one end until the other end of the scan. The acquisition device collects data in real time during the detection process. S7. Repeat step S6 above with the probe to scan and inspect different sides of the pipe to complete the scanning and inspection of all pipes. S8. Analyze the collected experimental data, differentiate the coupled magnetic field data and excitation magnetic field data collected from the upper and lower differential sensor components, and compare them with the data collected from the zero flux point sensor component. S9. After the experiment, remove the TMR sensor and put it back into the magnetic shielding container to avoid the influence of the external environment on the sensor and to avoid inaccurate data collection.

10. The implementation method according to claim 9, characterized in that, In steps S6 and S7, the scanning detection number for each side of the cladding pipe is no less than 3 times.

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