Design method of wireless passive electromagnetic ultrasonic detection system for oil and gas pipeline

Abstract

The present application belongs to the technical field of oil and gas pipeline nondestructive testing, and particularly relates to a design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines. The design method uses mutual inductance effect to directly couple the mapping impedance between coils into the corresponding circuit, without quantifying all electrical parameters in the electromagnetic ultrasonic testing system. Meanwhile, the resonant capacitance parameters are independently calculated and optimized according to the different circuit characteristics of the wireless passive electromagnetic ultrasonic testing system in the excitation stage and the receiving stage, so as to significantly improve the energy conversion efficiency of the wireless passive electromagnetic ultrasonic testing system and improve the signal-to-noise ratio of the signal. The design method comprises the following steps: drawing the equivalent circuit diagrams of the wireless passive electromagnetic ultrasonic testing system in the excitation stage and the receiving stage; determining the resonant circuit of the host receiving end; determining the resonant circuit of the transducer unit in the excitation stage; determining the resonant circuit of the host excitation end in the receiving stage; and determining the resonant circuit of the transducer unit.

Description

Technical Field

[0001] This invention belongs to the field of non-destructive testing technology for oil and gas pipelines, and particularly relates to the design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines. Background Technology

[0002] During the service life of petrochemical equipment, fixed-point thickness monitoring is crucial for ensuring the safety and reliability of storage tanks, pipelines, and other installations. Oil and gas pipelines and pressure vessels, in particular, are susceptible to corrosion under high-temperature and high-humidity conditions, leading to thinning of the metal walls. If the wall thickness thins to a critical range and is not detected and addressed in time, leaks can easily occur, causing significant economic losses and potentially endangering the lives of workers. Therefore, timely and efficient wall thickness monitoring of oil and gas pipelines and pressure vessels is of paramount practical importance.

[0003] As a relatively common thickness measurement technology, wired electromagnetic ultrasonic testing technology can transmit and receive ultrasonic data by connecting the transducer and the handheld device via a cable. However, unlike wired electromagnetic ultrasonic systems, wireless passive electromagnetic ultrasonic systems have characteristics such as three-coil cross-coupling, complex circuit structure, and different equivalent circuit diagrams for the excitation and reception stages. Therefore, existing resonant design methods are difficult to apply directly (due to the complex circuit of wireless passive electromagnetic ultrasonic systems).

[0004] Further research revealed that existing design methods for designing resonant circuits in wireless passive electromagnetic ultrasonic systems require precise quantification of various electrical parameters (such as self-inductance, mutual inductance, and resistance) and calculation of mapped impedance and resonant capacitance, making the design process cumbersome and susceptible to parameter errors. Therefore, there is an urgent need for those skilled in the art to develop a novel design method for wireless passive electromagnetic ultrasonic testing systems to address these technical problems. Summary of the Invention

[0005] This invention provides a design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines. This method utilizes the mutual inductance effect to directly couple the mapped impedance between coils into the corresponding circuits, without needing to quantify all electrical parameters of the electromagnetic ultrasonic testing system. Furthermore, this design method independently calculates and optimizes the resonant capacitance parameters for the different circuit characteristics of the excitation and reception phases of the wireless passive electromagnetic ultrasonic testing system, accurately achieving resonant matching of the multi-coil coupled system. This significantly improves the transduction efficiency of the wireless passive electromagnetic ultrasonic testing system and enhances the signal-to-noise ratio.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines includes the following steps:

[0008] Step S1: Determine the structural composition of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed based on the testing requirements;

[0009] The equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed are drawn.

[0010] Step S2: Based on the equivalent circuit diagram of the excitation stage and the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, the receiving coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed is separated from the host receiving end.

[0011] The equivalent inductance of the receiving coil was measured. With equivalent resistance And calculate the resonant capacitance required to match the host receiver. ;

[0012] Step S3: Based on the resonant capacitance required for the matching host receiver obtained in step S2. Determine the resonant circuit of the host receiver;

[0013] Step S4: Based on the equivalent circuit diagram of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the EMAT coil and the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, and make the EMAT coil tightly attached to the oil and gas pipeline to be tested.

[0014] Measuring the equivalent inductance of the EMAT coil With equivalent resistance And calculate the resonant capacitance required to match the EMAT coil. ;

[0015] Step S5: Based on the equivalent circuit diagram of the excitation stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, so that the transducer coil is suspended in the air and there is no metal medium around it.

[0016] Measuring the equivalent inductance of the transducer coil With equivalent resistance The resonant capacitance required for the transducer coil during the matching excitation stage was calculated as follows: The resonant capacitance required by the transducer unit during the matching excitation stage is ;in, ;

[0017] Step S6: Based on the resonant capacitance required by the transducer unit in the matching excitation stage obtained in step S5. Determine the resonant circuit of the transducer unit during the excitation phase;

[0018] Step S7: Connect the structural units separated in steps S2, S4, and S5, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the transducer unit in the excitation stage determined in step S6 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; keep the position of the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate it from the host excitation end.

[0019] Measuring the equivalent inductance of the excitation coil With equivalent resistance The resonant capacitance required at the host excitation end during the matching excitation stage was calculated as follows: ;

[0020] Step S8: Based on the equivalent circuit diagram of the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed.

[0021] Measuring the equivalent inductance of the excitation coil With equivalent resistance The parallel resonant capacitance required at the host excitation end during the matching reception stage was calculated as follows: ;

[0022] Step S9: Based on the parallel resonant capacitor required by the host excitation end in the matching reception stage obtained in step S8. Determine the resonant circuit at the host excitation end during the receiving phase;

[0023] Step S10: Connect the structural units separated in steps S7 and S8, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the host excitation end in the receiving stage determined in step S9 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; keep the position of the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate the EMAT coil from the transducer coil.

[0024] Measuring the equivalent inductance of the transducer coil With equivalent resistance And calculate the resonant capacitance required for the transducer coil in the matching receiving stage. and the resonant capacitance required by the transducer unit in the receiving stage ,in, .

[0025] A more preferred approach also includes the following steps:

[0026] Step S11: Calculate the resonant capacitance required for the matching transducer unit. ;in, ;

[0027] Based on the required resonant capacitance of the matched transducer unit Determine the resonant circuit of the transducer unit.

[0028] Preferably, the structure of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed in step S1 includes at least a wireless passive electromagnetic ultrasonic transducer unit, a wireless coupling unit, and an electromagnetic ultrasonic host.

[0029] The wireless passive electromagnetic ultrasonic transducer unit includes an electromagnetic ultrasonic transducer and a transducer coil; the wireless coupling unit includes an excitation coil and a receiving coil; and the electromagnetic ultrasonic host includes an excitation end and a receiving end.

[0030] The electromagnetic ultrasonic transducer includes a permanent magnet, a magnet backplate, an EMAT coil, and a transducer housing; the permanent magnet, the magnet backplate, and the EMAT coil are symmetrical about their central axis and are installed in the transducer housing from top to bottom.

[0031] Preferably, in steps S2, S5, and S8, the first resonant capacitor required for parallel resonance... ,satisfy: ;

[0032] in, The resonant frequency of the wireless passive electromagnetic ultrasonic testing system to be designed for oil and gas pipelines. The measured inductance of the coil is denoted as .

[0033] Preferably, in steps S4, S7, and S10, the second resonant capacitor required for parallel resonance... ,satisfy: ;

[0034] in, The resonant frequency of the wireless passive electromagnetic ultrasonic testing system to be designed for oil and gas pipelines. The measured coil inductance, The measured coil resistance.

[0035] This invention provides a design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines. Specifically, the design method includes the following steps: Step S1: Determine the structural configuration of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed based on the testing requirements; draw the equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed; Step S2: Based on the equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines obtained in Step S1, separate the receiving coil in the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines from the receiving end of the host machine; measure the equivalent inductance of the receiving coil. With equivalent resistance And calculate the resonant capacitance required to match the host receiver. Step S3: Based on the resonant capacitance required for the matching host receiver obtained in step S2. Step S4: Based on the equivalent circuit diagrams of the excitation and reception stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, obtained in Step S1, separate the EMAT coil and the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, and make the EMAT coil tightly attached to the oil and gas pipeline to be tested; measure the equivalent inductance of the EMAT coil. With equivalent resistance And calculate the resonant capacitance required to match the EMAT coil. Step S5: Based on the equivalent circuit diagram of the excitation stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, separate the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, so that the transducer coil is suspended in the air and there is no metal medium around it; measure the equivalent inductance of the transducer coil. With equivalent resistance The resonant capacitance required for the transducer coil during the matching excitation stage was calculated as follows: The resonant capacitance required by the transducer unit during the matching excitation stage is Step S6: Based on the resonant capacitance required by the transducer unit in the matching excitation stage obtained in step S5. Step S7: Determine the resonant circuit of the transducer unit in the excitation stage; Step S8: Connect the structural units separated in steps S2, S4, and S5, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the transducer unit in the excitation stage determined in step S6 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; Keep the position of the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate it from the host excitation end; Measure the equivalent inductance of the excitation coil. With equivalent resistance The resonant capacitance required at the host excitation end during the matching excitation stage was calculated as follows: Step S8: Based on the equivalent circuit diagram of the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; measure the equivalent inductance of the excitation coil. With equivalent resistance The parallel resonant capacitance required at the host excitation end during the matching reception stage was calculated as follows: Step S9: Based on the parallel resonant capacitor required by the host excitation end in the matching receiving stage obtained in step S8. Step S10: Determine the resonant circuit of the host excitation end in the receiving stage; Step S7: Connect the structural units separated in Step S7 and Step S8, as well as the resonant circuit of the host receiving end determined in Step S3 and the resonant circuit of the host excitation end in the receiving stage determined in Step S9, back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; Keep the position of the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate the EMAT coil from the transducer coil; Measure the equivalent inductance of the transducer coil. With equivalent resistance And calculate the resonant capacitance required for the transducer coil in the matching receiving stage. and the resonant capacitance required by the transducer unit in the receiving stage .

[0036] The design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines, which has the above-mentioned steps, has at least the following technical advantages compared with the prior art:

[0037] (1) This design method directly couples the mapped impedance between each coil to the corresponding circuit. Without quantifying all the electrical parameters of the system, the mapped impedance and resonant capacitance can be calculated. The resonant capacitance parameters are independently calculated and optimized for the different circuit characteristics of the excitation and reception stages in the wireless passive electromagnetic ultrasonic detection process. This achieves accurate resonance matching of the multi-coil coupled system and simplifies the design complexity of the multi-coil parallel resonant network.

[0038] (2) Compared with the existing wireless passive electromagnetic ultrasonic testing system, the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines obtained by the design method has greatly improved the wireless energy transmission efficiency of each resonant circuit, and can selectively amplify signals of specific frequencies; it has expanded the applicable distance range of the testing system and reduced the demand for transmission power.

[0039] (3) The design method provided by the present invention gets rid of the constraints of cables and significantly improves the working efficiency of oil and gas pipeline wall thickness detection. Compared with the existing wireless passive piezoelectric ultrasonic technology, it can work normally in various harsh working conditions of petrochemical equipment and does not require surface treatment of the test piece. Attached Figure Description

[0040] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the following drawings:

[0041] Figure 1 A flowchart illustrating the design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines provided by the present invention;

[0042] Figure 2 A schematic diagram of the structure of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed.

[0043] Figure 3 A simplified equivalent circuit diagram of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines.

[0044] Figure 4 This is a simplified equivalent circuit diagram of the backplate eddy current circuit 18, the specimen eddy current circuit 19, and the EMAT coil 3.

[0045] Figure 5 This is a schematic diagram showing the changes in inductance, resistance, and frequency during the excitation phase at the host receiver.

[0046] Figure 6 A simplified circuit diagram of a wireless passive electromagnetic ultrasonic testing system during the excitation phase;

[0047] Figure 7 A simplified circuit diagram of a wireless passive electromagnetic ultrasonic testing system in the receiving phase.

[0048] Figure 8a A schematic diagram of the experimental results of the wireless passive electromagnetic ultrasonic testing system before the addition of the resonant circuit;

[0049] Figure 8b A schematic diagram of the experimental results of the wireless passive electromagnetic ultrasonic testing system after adding a resonant circuit.

[0050] Figure label:

[0051] 1. Permanent magnet; 2. Magnet backplate; 3. EMAT coil; 4. Transducer housing; 5. Transducer coil; 6. Excitation coil; 7. Receiving coil; 8. Transducer unit resonant circuit; 9. Main excitation end resonant circuit; 10. Main receiver end resonant circuit; 11. Electromagnetic ultrasonic main unit; 12. Main excitation end; 13. Main receiver end; 14. Oil and gas pipeline under test; 15. Excitation circuit; 16. Receiving circuit; 17. Transducer unit circuit; 18. Backplate eddy current circuit; 19. Specimen eddy current circuit. Detailed Implementation

[0052] This invention provides a design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines. This method utilizes the mutual inductance effect to directly couple the mapped impedance between coils into the corresponding circuits, without needing to quantify all electrical parameters of the electromagnetic ultrasonic testing system. Furthermore, this design method independently calculates and optimizes the resonant capacitance parameters for the different circuit characteristics of the excitation and reception phases of the wireless passive electromagnetic ultrasonic testing system, accurately achieving resonant matching of the multi-coil coupled system. This significantly improves the transduction efficiency of the wireless passive electromagnetic ultrasonic testing system and enhances the signal-to-noise ratio.

[0053] Specifically, this invention provides a design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines, such as... Figure 1 As shown, it includes the following steps:

[0054] Step S1: Determine the structural composition of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed based on the testing requirements.

[0055] The equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed are drawn.

[0056] Among them, as a preferred embodiment of the present invention, such as Figure 2 As shown, the structure of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed in step S1 includes at least a wireless passive electromagnetic ultrasonic transducer unit, a wireless coupling unit, and an electromagnetic ultrasonic host.

[0057] Furthermore, the wireless passive electromagnetic ultrasonic transducer unit includes an electromagnetic ultrasonic transducer and a transducer coil 5; the wireless coupling unit includes an excitation coil 6 and a receiving coil 7; the electromagnetic ultrasonic host 11 includes a host excitation end 12 and a host receiving end 13. The electromagnetic ultrasonic transducer includes a permanent magnet 1, a magnet backplate 2, an EMAT coil 3, and a transducer housing 4; wherein the permanent magnet 1, the magnet backplate 2, and the EMAT coil 3 are symmetrical about their central axis and are installed sequentially from top to bottom inside the transducer housing 4.

[0058] It should be noted that the purpose of this setup is to understand the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed as a whole composed of multiple electromagnetically coupled objects. By determining the parallel resonant circuits (such as transducer unit resonant circuit 8, host excitation end resonant circuit 9, host receiver end resonant circuit 10, etc.) that need to be added to the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines, the specific structure of the required wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines can be finally designed.

[0059] In this process, the circuit of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed is first simplified, as detailed in the following example: Figure 3 As shown. At this time, the main current loops in the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines include the following five: excitation loop 15, receiving loop 16, transducer unit loop 17, backplate eddy current loop 18, and specimen eddy current loop 19. Since the electrical parameters of the backplate eddy current loop 18 and the specimen eddy current loop 19 cannot be measured and do not participate in resonance, the backplate eddy current loop 18, the specimen eddy current loop 19, and the EMAT coil 3 are further considered as a single coil connected to the power supply, thereby... Figure 3 Further simplification and reference as follows: Figure 4 As shown.

[0060] It should be noted that, to facilitate understanding of the present invention by those skilled in the art, the inventors further provide a wireless passive electromagnetic ultrasonic testing system for reference. In this system, the permanent magnet 1 is a cylindrical permanent magnet made of neodymium iron boron. To keep the overall volume of the electromagnetic ultrasonic transducer relatively small, the diameter of the cylindrical permanent magnet is approximately 30 mm, and the height is 10 mm. The EMAT coil 3 is a helical coil. The ratio of the diameter of the helical coil to the diameter of the cylindrical permanent magnet is 1:1.2, and the wire diameter is 0.2 mm. Furthermore, the transducer coil 5, the excitation coil 6, and the receiving coil 7 are all made of Litz wire with identical parameters, having a coil diameter of 40 mm, an inner diameter of 20 mm, and a wire diameter of 0.35 mm.

[0061] Step S2: Based on the equivalent circuit diagram of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, the receiving coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed is separated from the host receiver.

[0062] The equivalent inductance L1 and equivalent resistance R1 of the receiving coil were measured, and the resonant capacitance required to match the receiver of the host was calculated. .

[0063] Step S3: Based on the resonant capacitance required for the matching host receiver obtained in step S2. Determine the resonant circuit of the host receiver.

[0064] After completing step S1, proceed to steps S2 and S3. It is worth noting that, unlike existing wireless power transmission systems, the wireless passive electromagnetic ultrasonic detection system designed by the method provided in this invention has fundamentally different circuit characteristics in its excitation and reception phases. Specifically, in the excitation phase, the host excitation end generates a high-frequency electrical signal, which is transmitted along the direction of excitation coil-transducer coil-electromagnetic ultrasonic transducer; then the electromagnetic ultrasonic transducer converts the alternating current into ultrasonic waves. In the reception phase, when the ultrasonic wave reflects back to the electromagnetic ultrasonic transducer, it is first converted into alternating current, and then transmitted along the direction of electromagnetic ultrasonic transducer-transducer coil-receiving coil to the host receiving end.

[0065] Therefore, the changes in inductance, resistance, and frequency during the excitation phase at the host receiver can be referenced as follows: Figure 5 As shown. For the wireless passive electromagnetic ultrasonic testing system, during the excitation phase, the host excitation terminal 12 serves as the power supply for the system, and the EMAT coil 3 is equivalent to a load. See reference [example missing]. Figure 6 As shown. During the receiving phase, the EMAT coil 3 is used to receive weak ultrasonic echo signals, functioning equivalently as a power source, while the host excitation terminal 12 is considered as a load, as shown in the figure. Figure 7 As shown.

[0066] Furthermore, during wireless power transmission, the compensation capacitor in the secondary circuit is used to ensure the secondary circuit is in a resonant state, therefore the mapped impedance of the primary circuit does not need to be considered. Conversely, the compensation capacitor in the primary circuit is used to eliminate reactive power from the power supply, thus the mapped impedance of the secondary circuit needs to be considered. Based on this, when the receiving circuit 16 containing the receiving coil 7 is used as a secondary circuit, the influence of the transducer unit circuit 17 and the excitation circuit 15 does not need to be considered. In other words, when measuring the inductance and resistance of the receiving coil 7, there is no need for electromagnetic coupling between the receiving coil 7 and the excitation coil 6 or the transducer coil 5.

[0067] One point that needs further explanation is that when measuring the receiving coil in step S2, the electromagnetic coupling of the receiving coil 7 needs to be considered. This is because in actual thickness measurement work, the receiving coil 7 may have a metal backplate, and its location may be close to other components in the system or the oil and gas pipeline 14 to be measured. Therefore, it is necessary to measure its equivalent inductance L1 and equivalent resistance R1 at the actual working position of the receiving coil 7.

[0068] It is worth noting that, due to meeting Therefore, as a preferred embodiment of the present invention, during the measurement process in step S2, the first resonant capacitor required for parallel resonance is... ,satisfy: Where f is the resonant frequency of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, and L is the measured coil inductance.

[0069] Then, the internal resistance of the host receiver must be considered during the calculation. Finally, the determined host receiver resonant circuit 10 is connected in parallel with the receiving coil 7, and the location of the resonance peak is measured and observed to verify whether it matches the target resonant frequency. The results can be referenced as follows: Figure 5 As shown. Based on the above steps, the equivalent inductance and equivalent resistance of the receiving coil 7 are obtained as (5.73). 1.32 The resonant capacitor required for matching the host receiver 13 is: .

[0070] Step S4: Based on the equivalent circuit diagram of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, separate the EMAT coil and the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, and make the EMAT coil tightly attached to the oil and gas pipeline to be tested.

[0071] Measure the equivalent inductance L2 and equivalent resistance R2 of the EMAT coil, and calculate the resonant capacitance required to match the EMAT coil. .

[0072] After completing steps S2 and S3, proceed to step S4. It is worth noting that during the measurement of the equivalent inductance and equivalent resistance of the EMAT coil, due to… Not much smaller Therefore, as a preferred embodiment of the present invention, during the measurement process in step S4, the second resonant capacitor required for parallel resonance is... ,satisfy: Where f is the resonant frequency of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, L is the measured coil inductance, and R is the measured coil resistance.

[0073] Based on the above steps, the equivalent inductance and equivalent resistance of EMAT coil 3 are obtained as (465) 1.27 The resonant capacitor required to match EMAT coil 3 is: .

[0074] Step S5: Based on the equivalent circuit diagram of the excitation stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, so that the transducer coil is suspended in the air and there is no metal medium around it.

[0075] The equivalent inductance L3 and equivalent resistance R3 of the transducer coil were measured, and the resonant capacitance required for the transducer coil during the matching excitation stage was calculated. The resonant capacitance required by the transducer unit during the matching excitation stage is ;in, .

[0076] Step S6: Based on the resonant capacitance required by the transducer unit in the matching excitation stage obtained in step S5. The resonant circuit of the transducer unit during the excitation phase is determined.

[0077] Step S7: Connect the structural units separated in steps S2, S4, and S5, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the transducer unit in the excitation stage determined in step S6 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; keep the position of the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate it from the host excitation end.

[0078] The equivalent inductance L4 and equivalent resistance R4 of the excitation coil were measured, and the resonant capacitance required at the host excitation terminal during the matching excitation stage was calculated. .

[0079] After completing step S4, steps S5-S7 are then performed. Steps S5-S7 aim to determine the resonant circuits during the excitation phase. During the excitation phase, the transducer unit circuit 17 operates as a secondary circuit. Furthermore, when measuring the equivalent inductance L3 and equivalent resistance R3 of the transducer coil, electromagnetic coupling between the transducer coil 5 and the excitation coil 6 and receiving coil 7 is unnecessary. This is because the transducer coil has minimal coupling with other metal materials between the excitation coil 6 and the receiving coil 7; therefore, it is preferable to suspend it in the air to avoid interference from other metals during the measurement process.

[0080] Then, the resonant capacitance required by the transducer coil in the matched excitation stage is calculated as follows: The resonant capacitance required by the transducer unit during the matching excitation stage is Connect it in parallel with transducer coil 5, measure the overall inductance and resistance, and verify whether it matches the target resonant frequency.

[0081] Based on the above steps, the calculated equivalent inductance and equivalent resistance of transducer coil 5 are (4.17) 617 The resonant capacitance required for transducer coil 5 during the matching excitation stage is... The resonant capacitance required for the transducer unit in the matching excitation stage is: Finally, based on the obtained resonant capacitance of the matched transducer unit... 8. Determine the resonant circuit of the transducer unit during the excitation phase.

[0082] Then, the structural units separated in steps S2, S4, and S5, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the transducer unit in the excitation stage determined in step S6 are connected back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; and the excitation coil 6 is separated from the host excitation end 12 and fixed in its original position (above the transducer coil 5). The equivalent inductance L4 and equivalent resistance R4 of the excitation coil are measured, and the resonant capacitance required for matching the host excitation end in the excitation stage is calculated. .

[0083] Specifically, during the excitation phase, excitation circuit 15, acting as the primary circuit, requires electromagnetic coupling between excitation coil 6, transducer coil 5, and receiving coil 7 when measuring the inductance and resistance of the excitation coil. For receiving coil 7, it can be connected either to the host receiver 13 or in series with an impedance identical to the internal resistance of the host receiver 13. The second resonant capacitor required for parallel resonance during this measurement process... The calculation formula has been recorded in step S4 and will not be elaborated on here.

[0084] Based on the above steps, the equivalent inductance and equivalent resistance of the excitation coil 6 are obtained as (2.2) 14.5 The resonant capacitance required for excitation coil 6 during the matching excitation stage is... .

[0085] Step S8: Based on the equivalent circuit diagram of the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed is separated.

[0086] The equivalent inductance L5 and equivalent resistance R5 of the excitation coil were measured, and the parallel resonant capacitance required at the host excitation end for the matching receiving stage was calculated. .

[0087] Step S9: Based on the parallel resonant capacitor required by the host excitation end in the matching reception stage obtained in step S8. Determine the resonant circuit at the host excitation end during the receiving phase.

[0088] Step S10: Connect the structural units separated in steps S7 and S8, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the host excitation end of the receiving stage determined in step S9 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; keep the position of the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate the EMAT coil from the transducer coil.

[0089] The equivalent inductance L6 and equivalent resistance R6 of the transducer coil are measured, and the resonant capacitance required for the transducer coil in the matching receiving stage is calculated. and the resonant capacitance required by the transducer unit in the receiving stage ,in, .

[0090] After completing steps S5-S7, proceed to steps S8-S10. Steps S8-S10 aim to determine the resonant circuits in the receiving phase. Specifically, in the receiving phase, the excitation circuit 15 serves as the primary circuit; therefore, the electromagnetic coupling of the excitation coil 6 must be considered during its measurement.

[0091] It is worth noting that in actual thickness measurement work, the excitation coil 6 may have a metal backplate, and its position may be close to other components in the system or the oil / gas pipeline 14 to be measured; therefore, the equivalent inductance L5 and equivalent resistance R5 of the excitation coil are measured at the actual working position of the excitation coil 6. In the receiving stage, the excitation circuit 15 acts as a secondary circuit, and when measuring inductance and resistance, it is not necessary for the excitation coil 6 to be electromagnetically coupled to the transducer coil 5 and the receiving coil 7. The first resonant capacitor required for parallel resonance... The calculation formula has been recorded in step S2 and will not be elaborated on here.

[0092] Based on the above steps, the equivalent inductance and equivalent resistance of the excitation coil 6 are calculated to be (6.42) 1.62 The resonant capacitance required for the excitation coil 6 in the matching receiving stage is... Then, based on the calculated resonant capacitance required for the excitation coil 6 in the matching receiving stage, The host excitation end resonant circuit 9 in the receiving stage was determined.

[0093] Then, in the receiving stage, transducer unit circuit 17 serves as the primary circuit. When measuring the equivalent inductance and equivalent resistance of the transducer coil, electromagnetic coupling is required between the transducer coil 5, the excitation coil 6, and the receiving coil 7. For the receiving coil 7, an impedance with the same internal resistance as the host receiver terminal 13 can be connected in series. The second resonant capacitor required for parallel resonance... The calculation formula has been recorded in step S4 and will not be elaborated on here.

[0094] Based on the above steps, the equivalent inductance and equivalent resistance of the transducer coil 5 are obtained as (1.53) 10.54 The resonant capacitance required for the transducer coil 5 in the matching receiving stage is... The resonant capacitance required for the transducer unit in the matching receiving stage is .

[0095] On the other hand, as a preferred embodiment of the present invention, the design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines provided by the present invention further includes the following steps:

[0096] Step S11: Calculate the resonant capacitance required for the matching transducer unit. ;in, ;

[0097] Based on the required resonant capacitance of the matched transducer unit Determine the resonant circuit of the transducer unit.

[0098] It is worth noting that the aforementioned steps calculated the resonant capacitance of the host receiver's resonant circuit as follows: The resonant capacitance of the host excitation end resonant circuit is In step S11, the resonant capacitance required to match the transducer unit is further calculated. .

[0099] The experimental results of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines designed by the design method of this invention before and after adding a resonant circuit were compared. (The experimental results of the wireless passive electromagnetic ultrasonic testing system before adding the resonant circuit can be referred to as follows...) Figure 8a As shown; the experimental results of the wireless passive electromagnetic ultrasonic testing system after adding the resonant circuit can be referenced as follows. Figure 8b As shown in the figure, it can be seen that the design method of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines provided by the present invention simplifies the design and calculation of parallel resonance of complex electrical systems, significantly improves the energy conversion efficiency and improves the signal-to-noise ratio.

[0100] This invention provides a design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines. Specifically, the design method includes the following steps: Step S1: Determine the structural configuration of the wireless passive electromagnetic ultrasonic testing system to be designed for oil and gas pipelines based on the testing requirements; draw the equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system to be designed for oil and gas pipelines; Step S2: Based on the equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system to be designed for oil and gas pipelines obtained in Step S1, separate the receiving coil in the wireless passive electromagnetic ultrasonic testing system to be designed for oil and gas pipelines from the host receiver; measure the equivalent inductance L1 and equivalent resistance R1 of the receiving coil, and calculate the resonant capacitance required to match the host receiver. Step S3: Based on the resonant capacitance required for the matching host receiver obtained in step S2. Step S4: Based on the equivalent circuit diagrams of the excitation and reception stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, obtained in Step S1, separate the EMAT coil and the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, and make the EMAT coil tightly attached to the oil and gas pipeline to be tested; measure the equivalent inductance L2 and equivalent resistance R2 of the EMAT coil, and calculate the resonant capacitance required to match the EMAT coil. Step S5: Based on the equivalent circuit diagram of the excitation stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, separate the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, so that the transducer coil is suspended in the air and there is no metal medium around it; measure the equivalent inductance L3 and equivalent resistance R3 of the transducer coil, and calculate the resonant capacitance required for the transducer coil in the matching excitation stage. The resonant capacitance required by the transducer unit during the matching excitation stage is Step S6: Based on the resonant capacitance required by the transducer unit in the matching excitation stage obtained in step S5. Step S7: Determine the resonant circuit of the transducer unit in the excitation stage; Step S8: Connect the structural units separated in steps S2, S4, and S5, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the transducer unit in the excitation stage determined in step S6 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; Keep the position of the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate it from the host excitation end; Measure the equivalent inductance L4 and equivalent resistance R4 of the excitation coil, and calculate the resonant capacitance required for the host excitation end in the matching excitation stage. Step S8: Based on the equivalent circuit diagram of the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed is separated; the equivalent inductance L5 and equivalent resistance R5 of the excitation coil are measured, and the parallel resonant capacitance required for the matching receiving stage host excitation end is calculated. Step S9: Based on the parallel resonant capacitor required by the host excitation end in the matching receiving stage obtained in step S8. Step S10: Determine the resonant circuit of the host excitation end in the receiving stage; Step S7: Connect the structural units separated in steps S7 and S8, the resonant circuit of the host receiving end determined in step S3, and the resonant circuit of the host excitation end in the receiving stage determined in step S9 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; Keep the position of the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate the EMAT coil from the transducer coil; Measure the equivalent inductance L6 and equivalent resistance R6 of the transducer coil, and calculate the resonant capacitance required to match the transducer coil in the receiving stage. and the resonant capacitance required by the transducer unit in the receiving stage .

[0101] The design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines, which has the above-mentioned steps, has at least the following technical advantages compared with the prior art:

[0102] (1) This design method directly couples the mapped impedance between each coil to the corresponding circuit. Without quantifying all the electrical parameters of the system, the mapped impedance and resonant capacitance can be calculated. The resonant capacitance parameters are independently calculated and optimized for the different circuit characteristics of the excitation and reception stages in the wireless passive electromagnetic ultrasonic detection process. This achieves accurate resonance matching of the multi-coil coupled system and simplifies the design complexity of the multi-coil parallel resonant network.

[0103] (2) Compared with the existing wireless passive electromagnetic ultrasonic testing system, the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines obtained by the design method has greatly improved the wireless energy transmission efficiency of each resonant circuit, and can selectively amplify signals of specific frequencies; it has expanded the applicable distance range of the testing system and reduced the demand for transmission power.

[0104] (3) The design method provided by the present invention gets rid of the constraints of cables and significantly improves the working efficiency of oil and gas pipeline wall thickness detection. Compared with the existing wireless passive piezoelectric ultrasonic technology, it can work normally in various harsh working conditions of petrochemical equipment and does not require surface treatment of the test piece.

[0105] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A design method for a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines, characterized in that, The steps include the following: Step S1: Determine the structural composition of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed based on the testing requirements; The equivalent circuit diagrams of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed are drawn. Step S2: Based on the equivalent circuit diagram of the excitation stage and the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in Step S1, the receiving coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed is separated from the host receiving end. The equivalent inductance L1 and equivalent resistance R1 of the receiving coil were measured, and the resonant capacitance required to match the receiver of the host was calculated. ; Step S3: Based on the resonant capacitance required for the matching host receiver obtained in step S2. Determine the resonant circuit of the host receiver; Step S4: Based on the equivalent circuit diagram of the excitation and receiving stages of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the EMAT coil and the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, and make the EMAT coil tightly attached to the oil and gas pipeline to be tested. Measure the equivalent inductance L2 and equivalent resistance R2 of the EMAT coil, and calculate the resonant capacitance required to match the EMAT coil. ; Step S5: Based on the equivalent circuit diagram of the excitation stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, so that the transducer coil is suspended in the air and there is no metal medium around it. The equivalent inductance L3 and equivalent resistance R3 of the transducer coil were measured, and the resonant capacitance required for the transducer coil during the matching excitation stage was calculated. The resonant capacitance required by the transducer unit during the matching excitation stage is ;in, ; Step S6: Based on the resonant capacitance required by the transducer unit in the matching excitation stage obtained in step S5. Determine the resonant circuit of the transducer unit during the excitation phase; Step S7: Connect the structural units separated in steps S2, S4, and S5, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the transducer unit in the excitation stage determined in step S6 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; keep the position of the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate it from the host excitation end. The equivalent inductance L4 and equivalent resistance R4 of the excitation coil were measured, and the resonant capacitance required at the host excitation terminal during the matching excitation stage was calculated. ; Step S8: Based on the equivalent circuit diagram of the receiving stage of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed obtained in step S1, separate the excitation coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed. The equivalent inductance L5 and equivalent resistance R5 of the excitation coil were measured, and the parallel resonant capacitance required at the host excitation end for the matching receiving stage was calculated. ; Step S9: Based on the parallel resonant capacitor required by the host excitation end in the matching reception stage obtained in step S8. Determine the resonant circuit at the host excitation end during the receiving phase; Step S10: Connect the structural units separated in steps S7 and S8, the resonant circuit of the host receiver determined in step S3, and the resonant circuit of the host excitation end in the receiving stage determined in step S9 back to the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed; keep the position of the transducer coil in the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed unchanged, and separate the EMAT coil from the transducer coil. The equivalent inductance L6 and equivalent resistance R6 of the transducer coil are measured, and the resonant capacitance required for the transducer coil in the matching receiving stage is calculated. and the resonant capacitance required by the transducer unit in the receiving stage ,in, .

2. The design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines according to claim 1, characterized in that, It also includes the following steps: Step S11: Calculate the resonant capacitance C required for the matching transducer unit. t ;in, ; Based on the required resonant capacitance C of the matched transducer unit t Determine the resonant circuit of the transducer unit.

3. The design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines according to claim 1, characterized in that, The structure of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed in step S1 includes at least a wireless passive electromagnetic ultrasonic transducer unit, a wireless coupling unit, and an electromagnetic ultrasonic host. The wireless passive electromagnetic ultrasonic transducer unit includes an electromagnetic ultrasonic transducer and a transducer coil; the wireless coupling unit includes an excitation coil and a receiving coil; and the electromagnetic ultrasonic host includes an excitation end and a receiving end. The electromagnetic ultrasonic transducer includes a permanent magnet, a magnet backplate, an EMAT coil, and a transducer housing; the permanent magnet, the magnet backplate, and the EMAT coil are symmetrical about their central axis and are installed in the transducer housing from top to bottom.

4. The design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines according to claim 1, characterized in that, In steps S2, S5, and S8, the first resonant capacitor C1 required for parallel resonance satisfies: ; Where f is the resonant frequency of the wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines to be designed, and L is the measured coil inductance.

5. The design method of a wireless passive electromagnetic ultrasonic testing system for oil and gas pipelines according to claim 1, characterized in that, In steps S4, S7, and S10, the second resonant capacitor C2 required for parallel resonance satisfies: ; Where f is the resonant frequency of the wireless passive electromagnetic ultrasonic testing system for the oil and gas pipeline to be designed, L is the measured coil inductance, and R is the measured coil resistance.

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