A non-excavation type buried pipeline damage detection probe and detection method

Abstract

The application belongs to the field of metal pipeline damage detection, and provides a non-excavation type buried pipeline damage detection probe and a detection method. The non-excavation type buried pipeline damage detection probe comprises a detection probe shell, an excitation coil group arranged in the detection probe shell, and a magnetic field measurement sensor group. The magnetic field measurement sensor group comprises a pickup coil and a magnetic field strength detection bridge circuit. The pickup coil is used for sensing the magnetic flux change of the magnetic field generated by the excitation coil group in the axial direction of the excitation coil and converting the magnetic flux change into a first output voltage. The magnetic field strength detection bridge circuit is used for sensing the magnetic field strength of the magnetic field generated by the excitation coil in two mutually perpendicular radial directions of the excitation coil and converting the magnetic field strength into a second output voltage. Then, whether the buried pipeline has damage is judged according to the comparison result of the first output voltage and the second output voltage. The application can effectively detect the damage defects of the in-service buried pipeline without excavation and affecting the normal operation of the pipeline.

Description

Technical Field

[0001] This invention belongs to the field of metal pipeline damage detection, and particularly relates to a trenchless buried pipeline damage detection probe and detection method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] During long-term service, buried pipelines are inevitably affected by various factors such as soil corrosion, third-party intrusion, geological disasters, and corrosive components in the transported medium. These factors can cause various forms of damage to the pipeline body, including cracks, corrosion, and severe deformation, reducing its service life and reliability and posing potential dangers to its safe operation. Failure to detect and warn of these issues in a timely manner often leads to catastrophic consequences. Therefore, regular pipeline inspections, risk assessments, and integrity management are essential to promptly identify potential safety hazards. However, the underground installation method increases the difficulty of detecting pipeline damage.

[0004] Conventional inspection methods involve placing probes on or near the surface of pipes to detect cracks, corrosion, pitting, or other wall thickness defects beneath the anti-corrosion coating. This approach is unsuitable for detecting damage in buried pipelines. Currently, the commonly used ultrasonic guided wave inspection method for buried pipelines requires excavating a section of the pipeline to install the probe, followed by manual re-burying. This method is inefficient, time-consuming, and demands a high level of experience and skill from the personnel, leading to high rates of misjudgment and missed detection. Furthermore, re-burying the pipeline introduces new damage risks, failing to meet the demands of modern pipeline safety operation and inspection. Summary of the Invention

[0005] To address the technical problems mentioned above, this invention provides a trenchless buried pipeline damage detection probe and method, which can effectively detect damage and defects in in-service buried pipelines without excavation or affecting normal pipeline operation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a trenchless buried pipeline damage detection probe.

[0008] A trenchless buried pipeline damage detection probe includes:

[0009] The detection probe housing and the excitation coil assembly and magnetic field measurement sensor assembly housed therein;

[0010] The excitation coil group includes an excitation coil, a compensation coil, and an impedance matching circuit; the excitation coil is used to generate the main excitation magnetic field for detection; the compensation coil is used to provide a compensation excitation magnetic field for the main excitation magnetic field; the impedance matching circuit is used to match the inductive reactance of the excitation coil and the compensation coil.

[0011] The magnetic field measurement sensor group includes a pickup coil and a magnetic field strength detection bridge circuit. The pickup coil is used to sense the change in magnetic flux of the magnetic field generated by the excitation coil group in the direction of the excitation coil axis and convert it into a first output voltage. The magnetic field strength detection bridge circuit is used to sense the magnetic field strength of the magnetic field generated by the excitation coil group in two mutually perpendicular radial directions of the excitation coil and convert it into a second output voltage. Then, the buried pipeline is judged to have damage based on the comparison result of the first output voltage and the second output voltage.

[0012] In one implementation, the impedance matching circuit is composed of a capacitor bank formed by connecting multiple non-polar capacitors in series and parallel. The total capacitance of the capacitor bank is adjusted to match the corresponding operating frequency.

[0013] In one implementation, the excitation coil group is connected to a harmonic excitation source. When the harmonic excitation source consists of two frequency components, the total capacitance of the capacitor group is: ;in ω 1. ω 2 and A 1. A 2 represents the angular frequency and amplitude of the two components of the harmonic excitation source, respectively; when the harmonic consists of more than two frequencies, the total capacitance of the capacitor bank is the average value of the matching capacitance values ​​of any two frequencies.

[0014] In one embodiment, the pickup coil consists of two induction coils with the same number of turns but opposite winding directions connected in series. The two induction coils are arranged symmetrically along the radial direction of the excitation coil group. The induction coils are installed near the zero magnetic flux of the excitation coil group to sense changes in the magnetic flux of the magnetic field generated by the excitation coil group.

[0015] In one implementation, the first output voltage obtained by the pickup coil is: ;in, G This is the gain of the preamplifier. V coil+ and V coil- These are the induced electromotive forces of the two induction coils in the pickup coil.

[0016] In one embodiment, the magnetic field strength detection bridge circuit includes a magnetic field sensor, an operational amplifier, and a detection resistor; the magnetic field sensor is arranged radially symmetrically; the second output voltage obtained by the magnetic field strength detection bridge circuit is: ;

[0017] Where R is the sensing resistor; G is the gain of the operational amplifier, R TMR1 R TMR2 and △R TMR1 , △R TMR2 V represents the static resistance value of the two magnetic field sensors and the change in resistance caused by the change in the magnetic field, respectively. s This is the reference median voltage.

[0018] In one implementation, the radius of the excitation coil is larger than that of the compensation coil, and the two are arranged concentrically with the same winding direction, so that the magnetic field vectors generated after energization have the same direction.

[0019] In one embodiment, the probe housing includes a housing component and a probe support component; the housing component is used to fix the probe support component; the probe support component is used to mount and fix the excitation coil assembly and the magnetic field sensor assembly.

[0020] In one implementation, the probe bracket component adjusts the zero magnetic flux position of the excitation coil group via a guide rail, adjusts the installation position of the magnetic field measurement sensor group via double nuts to place it near the zero magnetic field strength plane, and ensures the radial relative position of the sensors within a measurement axis.

[0021] A second aspect of the present invention provides a detection method using a trenchless buried pipeline damage detection probe.

[0022] A detection method using a trenchless buried pipeline damage detection probe, comprising:

[0023] The harmonic excitation source is converted into a magnetic field using an excitation coil group;

[0024] The magnetic flux change along the axis of the excitation coil is converted into a first output voltage by using the pickup coil to induce the excitation coil group.

[0025] The magnetic field strength of the magnetic field generated by the induction excitation coil group of the bridge circuit is detected in two mutually perpendicular radial directions of the excitation coil and converted into a second output voltage.

[0026] The comparison between the first and second output voltages is used to determine whether there is damage to the buried pipeline.

[0027] The beneficial effects of this invention are:

[0028] The trenchless buried pipeline damage detection probe of the present invention consists of a detection probe shell and an excitation coil group and a magnetic field measurement sensor group installed therein. The magnetic field measurement sensor group senses the change in magnetic flux of the magnetic field generated by the excitation coil group in the direction of the excitation coil axis and converts it into a first output voltage. The magnetic field strength in the two mutually perpendicular radial directions of the excitation coil is converted into a second output voltage. The presence of damage to the buried pipeline is determined by comparing the first output voltage and the second output voltage. This enables effective detection of damage defects in in-service buried pipelines without excavation or affecting the normal operation of the pipeline, avoiding economic losses and the risk of secondary damage to the pipeline caused by work stoppage, excavation, and reburying of the pipeline.

[0029] The magnetic field strength detection bridge circuit of the present invention can effectively cancel the interference of power frequency magnetic field and the defect noise interference introduced by jitter during the handheld probe detection process, effectively reducing the false detection rate and the difficulty of operation during the detection process. When using it, there is no need to deliberately avoid high-voltage power transmission networks and high-power electrical equipment. Moreover, the excitation magnetic field has strong focusing performance, which improves the detection accuracy and has wide applicability. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a schematic diagram of the overall structure of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the excitation coil group of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the magnetic field strength detection bridge circuit of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of a set of pickup coils connected in an embodiment of the trenchless buried pipeline damage detection probe disclosed in this invention.

[0035] Figure 5 This is a circuit diagram of a non-excavation buried pipeline damage detection probe according to an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the probe housing of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram of the outer shell components of a trenchless buried pipeline damage detection probe according to an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the probe support component of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the mounting plate of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of a coil winding frame for a trenchless buried pipeline damage detection probe according to an embodiment of the present invention.

[0041] Figure 11 This is a schematic diagram of the data transmission line of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0042] Figure 12 This is a schematic diagram of the coil power supply line of a trenchless buried pipeline damage detection probe disclosed in one embodiment of the present invention;

[0043] Figure 13 This is a schematic diagram illustrating the probe detection process of a trenchless buried pipeline damage detection probe according to an embodiment of the present invention.

[0044] Figure 14 This is a schematic diagram of the parallel pipeline damage detection results of a trenchless buried pipeline damage detection probe disclosed in an embodiment of the present invention.

[0045] Figure 15 This is a schematic diagram of the parallel pipeline routing detection results of a trenchless buried pipeline damage detection probe disclosed in an embodiment of the present invention.

[0046] Figure 16 This is a schematic diagram illustrating the implementation of pipeline route orientation detection using a trenchless buried pipeline damage detection probe according to an embodiment of the present invention.

[0047] in:

[0048] 1. Excitation coil assembly; 11. Excitation coil; 12. Compensation coil; 13. Impedance matching circuit; 14. 2-pin plastic aviation connector;

[0049] 2. Magnetic field sensor assembly; 21. Pickup coil; 211. Induction coil; 22. Magnetic field strength detection bridge circuit; 23. 16-pin plastic aviation connector; 221. Magnetic field sensor; 222. Operational amplifier; 223. Resistor; 224. Sensor mounting plate; 225. Circuit board mounting plate;

[0050] 3. Detection probe housing; 31. Housing components; 311. Housing; 312. Sealing plate; 32. Probe bracket components; 321. Fixing plate; 322. Circular excitation coil side plate; 323. Circular compensation coil side plate; 324. Coil-shaped induction coil winding frame; 325. Adjusting shims;

[0051] 4. Data transmission line; 41. Connector plug; 42. Data cable;

[0052] 5. Coil power supply wire; 51. Power connector plug; 52. Power cable;

[0053] a1, start of excitation coil; a2, end of excitation coil; b1, start of compensation coil; b2, end of compensation coil; c1, input of impedance matching circuit; c2, output of impedance matching circuit. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0056] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0057] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.

[0058] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0059] according to Figure 1 An embodiment of the present invention provides a trenchless buried pipeline damage detection probe, comprising:

[0060] The detection probe housing 3 and the excitation coil assembly 1 and magnetic field measurement sensor assembly 2 disposed therein;

[0061] Excitation coil group 1 is used to generate a strong focused excitation magnetic field. By loading harmonic current into excitation coil group 1, a strong focused harmonic magnetic field is generated and penetrates the soil to be focused onto the buried pipeline, thereby exciting the pipeline to generate an induction magnetic field that carries the health information of the pipeline body.

[0062] Excitation coil group 1 specifically includes excitation coil 11, compensation coil 12, impedance matching circuit 13, and 2-pin plastic aviation connector 14, such as Figure 2 As shown. The first end a1 of the excitation coil 11 is soldered to the output end c2 of the impedance matching circuit 13, and the last end a2 is soldered to the first end b1 of the compensation coil 12; the last end b2 of the compensation coil 12 is soldered to pin d2 of the 2-pin plastic aviation connector 14; the input end of the impedance matching circuit 13 is soldered to pin d1 of the 2-pin plastic aviation connector 14. The excitation coil 11 is used to generate the main excitation magnetic field for detection; the compensation coil 12 is used to provide a compensation excitation magnetic field for the main excitation magnetic field; the impedance matching circuit 13 is used to match the inductive reactance of the excitation coil and the compensation coil.

[0063] In this embodiment, the excitation coil 11 is a circular coil used to generate the main excitation magnetic field for detection, and its radius determines the radiation range of the excitation magnetic field; the compensation coil 12 is a circular coil used to provide the compensation excitation magnetic field, and its radius determines the radiation range of the focusing magnetic field.

[0064] In this embodiment, the radius of the excitation coil 11 is larger than that of the compensation coil 12. The two coils are concentrically arranged and have the same winding direction. The magnetic field vectors generated after energization are in the same direction. The excitation coil 11 and the compensation coil 12 are uniform multi-turn coils. The material they are made of is insulated wire, preferably enameled copper round wire conforming to the standard specified in GB6109.1-2008. The excitation coil 11 and the compensation coil 12 can be coils of other regular or irregular shapes.

[0065] The impedance matching circuit 13 in this embodiment is used to match the inductive reactance of the excitation coil 11 and the compensation coil 12, so as to reduce the requirements on the output voltage amplitude and power performance of the harmonic excitation source. The impedance matching circuit 13 is composed of an adjustable capacitor group formed by multiple non-polar capacitors connected in series and parallel. The corresponding operating frequency is matched by adjusting the total capacitance of the capacitor group.

[0066] The method for determining the total capacitance of the adjustable capacitor bank is as follows:

[0067] The detection probe at a frequency of fThe total impedance X under a single-frequency excitation voltage is:

[0068]

[0069] In the formula, R is the resistance value of the excitation coil group; To excite the inductive reactance of the coil group; L is the capacitive reactance of the impedance matching circuit; L is the inductance of the corresponding compensation phase excitation coil group, which can be obtained by measuring with an impedance analyzer; C is the capacitance of the matching capacitor. At this time, the current of the excitation coil group... Furthermore, the magnetic field strength is proportional to the excitation current; if the harmonic excitation source is... ω 1 and ω It consists of two frequency components, with an intensity ratio of 2. A 1: A 2. The capacitance value of the matching capacitor

[0070]

[0071] In the formula ω 1. ω 2 and A 1. A 2 represents the angular frequency and amplitude of the two components of the harmonic excitation source, respectively. Once the components of the harmonic excitation source are determined, the system after impedance matching requires a small total amplitude of the input excitation voltage U, and low requirements for the output voltage and power performance of the harmonic excitation source. Furthermore, when the harmonic consists of more than two frequencies, the capacitance value of the matching capacitor is the average of the capacitance values ​​of any two frequencies.

[0072] In this embodiment, the 2-pin plastic aviation connector 14 is used to connect the harmonic excitation source output and the impedance matching circuit 13 input. It consists of solid copper gold-plated pins and a plastic housing, with a rated circuit current of not less than 10A. Furthermore, input terminals 1 and 2 of the 2-pin plastic aviation connector 14 correspond to the positive and negative terminals of the harmonic excitation source output, respectively, and the harmonic excitation source voltage is:

[0073]

[0074] In the formula, A i , ω i and φ i The first harmonic excitation source i The amplitude, angular frequency, and initial phase angle of the component; n This represents the number of harmonics.

[0075] In this embodiment, the magnetic field measurement sensor group 2 is used to measure the intensity or rate of change of the induced magnetic field generated by the tube, and converts the measurement result into a voltage value output connected to the signal acquisition system, thereby completing the identification of the tube damage target. At the same time, a zero magnetic flux position is constructed to reduce the interference of the excitation magnetic field, thereby improving the dynamic range of the subsequent amplifier circuit; a magnetic field strength detection bridge is designed to cancel power frequency interference and reduce detection noise, thereby improving the accuracy of damage detection.

[0076] The magnetic field measurement sensor group 2 in this embodiment includes a pickup coil 21 and a magnetic field strength detection bridge circuit 22. The pickup coil 21 is used to sense the change in magnetic flux of the magnetic field generated by the excitation coil group in the direction of the excitation coil axis and convert it into a first output voltage. The magnetic field strength detection bridge circuit 22 is used to sense the magnetic field strength of the magnetic field generated by the excitation coil group in two mutually perpendicular radial directions of the excitation coil and convert it into a second output voltage. Then, the buried pipeline is judged to have damage based on the comparison result of the first output voltage and the second output voltage.

[0077] like Figure 3 As shown, the pickup coil 21 and the magnetic field strength detection bridge circuit 22 are soldered to the 16-pin plastic aviation plug 23 respectively; the pickup coil 21 measures the rate of change of magnetic flux in the z-axis direction; the magnetic field strength detection bridge circuit 22 measures the magnetic field strength in the x and y-axis directions.

[0078] In this embodiment, the pickup coil 21 is composed of two circular induction coils 211 connected in series, each with the same number of turns but in opposite directions. The circular induction coil 211 is a uniform multi-turn coil, and its material is an insulated wire, preferably an enameled copper round wire conforming to the standard specified in GB6109.1-2008.

[0079] To address the issue of power frequency magnetic field interference and induced voltage noise introduced by the excitation magnetic field limiting the dynamic performance of the amplifier module in the acquisition system, in this embodiment, the induction coils 211 are all installed near the zero magnetic flux of the excitation coil group 1, and two induction coils 211 arranged radially symmetrically constitute a set of pickup coils 21, such as... Figure 3 As shown in position I.

[0080] In other embodiments, the induction coil 211 can be installed at any position radially in the excitation coil group 1 as needed, but it must be ensured that the magnetic flux of the two induction coils is consistent and they are arranged in a mirror-symmetric manner, such as... Figure 3 Position II is shown; the circular induction coil 211 can also be a coil of other regular or irregular shapes.

[0081] like Figure 4 As shown, after passing through the preamplifier stage, the output of a set of pickup coils 21 is...

[0082]

[0083] In the formula, G is the gain of the preamplifier, and Vcoil+ and Vcoil- are the induced electromotive forces of the two induction lines in a set of pickup coils, respectively. During the detection process, since the power grid or high-power electrical equipment is far from the detection probe, the strength of the power frequency magnetic field at the detection probe is basically the same, so the induced voltages generated by the power frequency magnetic field on the two induction coils 211 are basically the same. Therefore, the pickup coils 21 can largely cancel the noise introduced by the power frequency magnetic field.

[0084] The magnetic field strength detection bridge circuit 22 in this embodiment consists of a magnetic field sensor 221, an operational amplifier 222, a resistor 223, a sensor mounting plate 224, and a circuit board mounting plate 225. Figure 5 As shown. Magnetic field sensor 221 is preferably a tunnel magnetoresistive (TMR) sensor; operational amplifier 222 is preferably a high-precision operational amplifier with low input bias current and noise; resistor 223 is preferably a high-precision, low-temperature-drift thin-film resistor; sensor mounting plate 224 is used to mount magnetic field sensor 221, with one magnetic field sensor 221 mounted on its top and one on its bottom to measure the magnetic field strength in the x and y directions, respectively; circuit board mounting plate 225 is used to mount operational amplifier 222 and resistor 223.

[0085] To address the issues of false detections caused by interference from power frequency magnetic fields, interference from excitation magnetic fields, and noise introduced by probe jitter during the detection process, the sensor mounting plate 224 is placed near the zero magnetic field strength plane of the excitation coil group 1, so that the background excitation magnetic field received by the magnetic field sensor 221 is minimized, and the two magnetic field sensors 221 arranged radially symmetrically form a magnetic field strength detection bridge circuit 22 for measuring the axis.

[0086] The magnetic field sensor 221 can be installed at any position in the radial direction of the excitation coil group 1 as needed, but it must be ensured that the magnetic induction intensity of the two magnetic field sensors 221 is consistent and arranged in a mirror symmetrical manner; at the same time, a magnetic field strength detection bridge is designed to suppress the false defect noise caused by the disturbance of the output signal of the magnetic field sensor 221 due to probe jitter during the detection process.

[0087] like Figure 6 As shown, the output of the magnetic field strength detection bridge circuit 22 is a differential signal, and the circuit input reference voltage is Vs. Based on the virtual short and virtual open states of the operational amplifier, the outputs of operational amplifier 222 are respectively...

[0088]

[0089]

[0090] Where vz+ and vz- are the outputs of the operational amplifier, Vs is the reference midpoint voltage, and RTMR1 and RTMR2 are the static resistance values ​​of the two magnetic field sensors; after passing through the preamplifier, the output of a set of magnetic field strength detection bridge circuit 22 is...

[0091]

[0092] Where G is the gain of the preamplifier, and ΔRTMR1 and ΔRTMR2 are the resistance changes of the two magnetic field sensors caused by the change of the magnetic field.

[0093] When probe jitter occurs during detection, the jitter patterns of the two magnetic field sensors 221 within the same group are basically consistent, resulting in essentially identical magnetic field disturbances. At this time, the resistance changes of the magnetic field sensor 221 caused by the disturbed magnetic field are essentially canceled out. Therefore, this circuit can greatly suppress the noise introduced by probe jitter. Furthermore, the magnetic field strength detection bridge circuit 22 can also greatly cancel out the noise introduced by the power frequency magnetic field, with a principle similar to that described for the pickup coil 21.

[0094] The two magnetic field sensors 221 in the magnetic field strength detection bridge circuit 22 are not limited to TMR sensors, but can also be induction coils, other magnetic field measuring devices or products, etc.

[0095] The 16-pin plastic aviation connector 23 is used to connect the pickup coil 21, the magnetic field strength detection bridge circuit 22, and the input and output of the signal acquisition system. It consists of solid copper gold-plated pins and a plastic shell. Pins e1 and e2 of the 16-pin plastic aviation connector 23 are connected to the differential output terminals of one pickup coil 21, and pins e3 and e4 are connected to the differential output terminals of another pickup coil 21. Pins e5 and e6 are connected to the differential output of the x-axis magnetic field strength detection bridge circuit 22, pins e7 and e8 are connected to the differential output of another x-axis magnetic field strength detection bridge circuit 22, pins e9 and e10 are connected to the differential output of the y-axis magnetic field strength detection bridge circuit 22, and pins e11 and e12 are connected to the differential output of another y-axis magnetic field strength detection bridge circuit 22. Pin e13 is connected to the reference voltage Vs of the magnetic field strength detection bridge circuit 22, pin e14 is connected to the positive power supply VCC of the magnetic field strength detection bridge circuit 22, pin e15 is connected to the negative power supply VEE of the magnetic field strength detection bridge circuit 22, and pin e16 is connected to the power ground GND of the magnetic field strength detection bridge circuit 22.

[0096] The excitation magnetic field stimulates the pipe to generate an induced magnetic field containing information about the pipe's health. When there are no defects in the pipe, the changes in magnetic flux of the two induction coils 211 in the pickup coil 21 and the induced magnetic field strength measured by the two magnetic field sensors 221 in the magnetic field strength detection bridge circuit 22 are basically the same and consistent, and the output differential voltage remains unchanged. When there are defects in the pipe, the defect location is equivalent to a magnetic anomaly. At the same time, thanks to the special spatial arrangement of the two induction coils 211 or the two magnetic field sensors 221 in the same group, the changes in the magnetic flux of the induced magnetic field on the two induction coils or the differences in the induced magnetic field strength at the two magnetic field sensors 221 cause the differential voltage output of each measuring axis in the magnetic field sensor group 2 to change. This change can be used to identify defects.

[0097] The detection probe housing 3 is used to install the excitation coil group 1 and the magnetic field sensor group 2, which can ensure the relative position of the excitation coil group 1 and the magnetic field sensor group 2, and facilitate the adjustment of the installation position of the induction coil 211 and the magnetic field sensor 221. It has the advantages of simple structure and convenient installation.

[0098] The probe housing 3 specifically includes a housing component 31 and a probe support component 32, such as... Figure 7 As shown. The outer casing component 31 is used to fix the probe bracket component 32, making it convenient for the operator to hold. The probe bracket component 32 is used to install and fix the excitation coil group 1 and the magnetic field sensor group 2, and is glued to the outer casing component 31; the guide rail design facilitates the adjustment of the zero magnetic flux position of the induction coil 211, and the installation position of the magnetic field sensor 221 is adjusted by double nuts to make it near the zero magnetic field strength plane, and to ensure the radial relative position of the two sensors (induction coil 211 or magnetic field sensor 221) within one measuring axis (pickup coil 21 or magnetic field strength detection bridge circuit 22).

[0099] The outer casing component 31 consists of an outer casing 311 and a sealing plate 312. For example... Figure 8 As shown, the outer shell 311 is a rectangular shell with mounting bases for sealing plates 312 at the four corners and a mounting base for sensor mounting plate 224 at the bottom. Both mounting bases have threaded holes, and the sides have mounting holes for 2-pin plastic aviation connectors 14 and 16-pin plastic aviation connectors 23. The sealing plate 312 is a rectangular plate with through holes at the four corners, which is connected to the outer shell 311 by screws. All connecting parts are made of resin or non-metallic plastic, and can be a 3D printed one-piece structure or can be assembled from multiple parts.

[0100] The probe support component 32 consists of a fixing plate 321, a circular excitation coil side plate 322, a circular compensation coil side plate 323, a coil-shaped induction coil winding frame 324, and an adjusting shim 325. For example... Figure 9As shown, the fixing plate is circular, with a cylindrical excitation coil winding frame and a mounting base for the sensor mounting plate 224 on its top. The mounting base has threaded holes, and the bottom has a mounting guide rail for the coil winding frame 324, which facilitates the adjustment of the induction coil 211 to the zero magnetic flux position and ensures that the two induction coils 211 in a set of pickup coils 21 are located in the same radial direction; as Figure 10 As shown, the bottom of the coil winding frame 324 has a guide rail groove; the excitation coil side plate 322, the compensation coil side plate 323 and the coil winding frame 324 are glued to the fixing plate 321, and the sensor mounting plate 224 is connected to the fixing plate 321 by screws. The adjusting shim 325 is used to adjust the installation position of the sensor mounting plate 224 so that the magnetic field sensor 221 is located near the zero magnetic induction intensity plane; all connecting parts are made of resin or non-metallic plastic, and can be a 3D printed one-piece structure, or can be composed of multiple parts connected together.

[0101] like Figure 11 As shown in Figure 11, the data transmission line 4 is used to connect the magnetic field sensor group 2 and the acquisition system. One data transmission line includes two connector plugs 41 and a data cable 42. One end of the data transmission line 4 is connected to the 16-pin plastic aviation plug 23 on the detection probe, and the other end is connected to the data acquisition card. The connector plugs 41 are preferably connectors with non-magnetic housings to reduce the impact on the detected magnetic field. The data cable 42 is a 16-core shielded data cable, preferably a twisted-pair shielded cable, to suppress interference from environmental factors on the transmission of weak magnetic field signals.

[0102] like Figure 12 The coil power supply line 5 is used to connect the excitation coil group 1 and the harmonic excitation source. It includes two power connectors 51 and a power cable 52, as shown in Figure 12. One end of the coil power supply line 5 is connected to the 2-pin plastic aviation connector 14 on the detection probe, and the other end is connected to the harmonic excitation source. The power connectors 51 are preferably industrial power quick connectors with non-magnetic material shells, with a rated voltage of not less than 100V and a rated current of not less than 15A. The power cable 52 is a 2-core pure copper core sheathed cable that conforms to GB / T5023-2008 standard, with a cross-sectional area of ​​not less than 1 square millimeter.

[0103] Figure 13 This diagram illustrates the use of a detection probe for damage detection in parallel buried pipelines. View A shows the relative position of the magnetic field sensor group 2 of the detection probe to the parallel pipelines. As shown, pipelines I and II each have a defect at a different location. Above pipeline I is the Coil I+ coil of pickup coil I, and above pipeline II is the Coil I- coil of pickup coil I. The detection steps are as follows:

[0104] (1) Take the magnetic field sensor 221 out of the magnetic shielding barrel, insert the sensor into the straight plug socket on the sensor mounting plate 224, fix the sensor mounting plate and install the probe sealing plate 312;

[0105] (2) Connect the acquisition system and the detection probe with data transmission line 4, and connect the harmonic excitation source and the detection probe with coil power supply line 5;

[0106] (3) Install and fix one end of the position sensor on the detection probe and connect the line, and connect the other end to the acquisition system to synchronously record the probe position, so as to ensure that the acquired magnetic field data corresponds one-to-one with the detection probe position data;

[0107] (4) Move the detection probe to the area to be detected, turn on the detection equipment, and move the detection probe at a constant speed multiple times in the same direction above the pipeline to complete the detection;

[0108] (5) After the test is completed, remove the TMR magnetic sensor and put it back in the shielding bucket to avoid the external environment from interfering with the sensor accuracy and affecting the next test.

[0109] The detection method using a trenchless buried pipeline damage detection probe includes:

[0110] Step 1: Use an excitation coil group to convert the harmonic excitation source into a magnetic field;

[0111] Step 2: Utilize the pickup coil to induce the change in magnetic flux of the magnetic field generated by the excitation coil group along the axis of the excitation coil and convert it into the first output voltage;

[0112] Step 3: Detect the magnetic field strength of the magnetic field generated by the induction excitation coil group of the bridge circuit in two mutually perpendicular radial directions of the excitation coil and convert it into a second output voltage;

[0113] Step 4: Determine whether there is damage to the buried pipeline based on the comparison results of the first output voltage and the second output voltage.

[0114] Specifically, the excitation magnetic field stimulates the pipe to generate an induced magnetic field containing information about the pipe's health. When there are no defects in the pipe, the changes in magnetic flux of the induced magnetic field experienced by the two induction coils 211 in the pickup coil 21 and the induced magnetic field strength measured by the two high-sensitivity magnetic field sensors 221 in the magnetic field strength detection bridge circuit 22 are basically the same and consistent, and the output differential voltage remains unchanged. When there are defects in the pipe, the defect location is equivalent to a magnetic anomaly. At the same time, thanks to the special spatial arrangement of the two induction coils 211 or the two high-sensitivity magnetic field sensors 221 in the same group, the changes in the magnetic flux of the induced magnetic field experienced by the two induction coils or the differences in the induced magnetic field strength at the two high-sensitivity magnetic field sensors 221 cause the differential voltage output of each measuring axis in the magnetic field sensor group 2 to change. This change can be used to identify defects.

[0115] After the acquired probe data is processed for denoising (or target enhancement), the result is as follows: Figure 14 As shown: when there is a defect or damage in pipe I, the waveform of the collected data is in the form of a trough; when there is a defect or damage in pipe II, the waveform of the collected data is in the form of a peak.

[0116] like Figure 13 Parallel pipeline routing is performed in the direction shown in the middle view A. The data collected by the probe is denoised (or target augmented) and then subjected to gradient processing. The result is as follows. Figure 15 As shown: The detection probe can not only determine the number of pipes based on the number of troughs in the gradient waveform of the collected data, but also determine the spacing between pipes based on the zero-crossing distance of the gradient waveform. Figure 16 This diagram illustrates the implementation of a trenchless buried pipeline damage detection probe for pipeline route orientation detection.

[0117] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A trenchless buried pipeline damage detection probe, characterized in that, include: The detection probe housing and the excitation coil assembly and magnetic field measurement sensor assembly housed therein; The excitation coil group includes an excitation coil, a compensation coil, and an impedance matching circuit; The excitation coil is used to generate the main excitation magnetic field for detection; the compensation coil is used to provide a compensation excitation magnetic field for the main excitation magnetic field; the impedance matching circuit is used to match the inductive reactance of the excitation coil and the compensation coil. The magnetic field measurement sensor group includes a pickup coil and a magnetic field strength detection bridge circuit. The pickup coil is used to sense the change in magnetic flux of the magnetic field generated by the excitation coil group in the direction of the excitation coil axis and convert it into a first output voltage. The magnetic field strength detection bridge circuit is used to sense the magnetic field strength of the magnetic field generated by the excitation coil group in two mutually perpendicular radial directions of the excitation coil and convert it into a second output voltage. Then, the buried pipeline is judged to have damage based on the comparison result of the first output voltage and the second output voltage. The impedance matching circuit consists of a capacitor bank formed by multiple non-polar capacitors connected in series and parallel. The total capacitance of the capacitor bank is adjusted to match the corresponding operating frequency. The excitation coil group is connected to the harmonic excitation source. When the harmonic excitation source consists of two frequency components, the total capacitance of the capacitor group is: ;in ω 1. ω 2 and A 1. A 2 represents the angular frequency and amplitude of the two components of the harmonic excitation source, respectively; when the harmonic is composed of more than two frequencies, the total capacitance of the capacitor bank is the average value of the matching capacitance values ​​of any two frequencies; The pickup coil consists of two induction coils with the same number of turns but opposite winding directions connected in series. The two induction coils are arranged symmetrically along the radial direction of the excitation coil group. The induction coil is installed near the zero magnetic flux of the excitation coil group to sense the change in magnetic flux of the magnetic field generated by the excitation coil group. The magnetic field strength detection bridge circuit includes a magnetic field sensor, an operational amplifier, and a detection resistor; the magnetic field sensor is arranged radially symmetrically; the second output voltage obtained by the magnetic field strength detection bridge circuit is: ; Where R is the sensing resistor; G is the gain of the operational amplifier, R TMR1 R TMR2 and △R TMR1 , △R TMR2 V represents the static resistance value of the two magnetic field sensors and the change in resistance caused by the change in the magnetic field, respectively. s Reference median voltage; The radius of the excitation coil is larger than that of the compensation coil. The two are arranged concentrically and the coils are wound in the same direction. The magnetic field vectors generated after energization are in the same direction.

2. The trenchless buried pipeline damage detection probe as described in claim 1, characterized in that, The first output voltage obtained by the pickup coil is: ;in, G This is the gain of the preamplifier. V coil+ and V coil- These are the induced electromotive forces of the two induction coils in the pickup coil.

3. The trenchless buried pipeline damage detection probe as described in claim 1, characterized in that, The probe housing includes a housing component and a probe support component; the housing component is used to fix the probe support component; the probe support component is used to install and fix the excitation coil group and the magnetic field sensor group.

4. The trenchless buried pipeline damage detection probe as described in claim 3, characterized in that, The probe bracket component adjusts the zero magnetic flux position of the excitation coil group via the guide rail, and adjusts the installation position of the magnetic field measurement sensor group via double nuts to place it near the zero magnetic field strength plane, while ensuring the radial relative position of the sensors within one measurement axis.

5. A detection method using a trenchless buried pipeline damage detection probe as described in any one of claims 1-4, characterized in that, include: The harmonic excitation source is converted into a magnetic field using an excitation coil group; The magnetic flux change along the axis of the excitation coil is converted into a first output voltage by using the pickup coil to induce the excitation coil group. The magnetic field strength of the magnetic field generated by the induction excitation coil group of the bridge circuit is detected in two mutually perpendicular radial directions of the excitation coil and converted into a second output voltage. The comparison between the first and second output voltages is used to determine whether there is damage to the buried pipeline.

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