An array probe for eddy current inspection

Abstract

The application provides an array probe for eddy current testing. The array probe comprises a centering frame and flat coils arranged in the centering frame; the flat coils comprise excitation coils and receiving coils; the excitation coils are used for sending eddy current for testing; and the receiving coils are used for receiving feedback signals for testing. The application has the advantages that the application solves the problems of poor universality, high cost and low work efficiency of the existing eddy current probe scanning device; the internal multiplexing system of the application greatly reduces the adverse effects of mutual inductance, and programs the actual time when each coil is excited to send its eddy current signal. In the detection process, the phase and frequency of the signal can determine the defect depth of the target object, and the amplitude of the signal can determine the loss amount of the defect metal in the coil induction area; moreover, the closer to the excitation coil, the higher the sensitivity, and the detection has directionality, so that accurate detection is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of eddy current testing, and particularly relates to an array probe using eddy current testing. BACKGROUND

[0002] At present, non-destructive testing and non-destructive evaluation technology is an application engineering technology developed on the basis of physics, material science, fracture mechanics, mechanical engineering, electronics, computer technology, information technology and artificial intelligence and the like. With the development of modern industry and science and technology, non-destructive testing and non-destructive evaluation technology is increasingly valued by various industrial fields and scientific research departments. It not only plays an irreplaceable role in product quality control, which is recognized by numerous scientific and technical personnel and the business community, but also plays an important role in the in-service inspection of running equipment. As an emerging detection technology, it has the following characteristics: no need for a large number of reagents; no need for pretreatment work, simple sample preparation; even detection, online detection; no damage to the sample, no pollution and the like.

[0003] Non-destructive testing (NDT) is a general term for all technical means for detecting whether a detected object has defects or non-uniformity without damaging or affecting the use performance of the detected object, giving information about the size, position, nature and quantity of defects, and further determining the technical state of the detected object (such as whether it is qualified or not, the remaining life and the like).

[0004] Compared with destructive testing, non-destructive testing has the following significant features:

[0005] (1) Non-destructive

[0006] (2) Comprehensive

[0007] (3) Whole process

[0008] (4) Reliability issues.

[0009] Nondestructive testing is divided into conventional testing techniques and unconventional testing techniques. The conventional testing techniques are: ultrasonic testing (abbreviated as UT), radiographic testing (abbreviated as RT), magnetic particle testing (abbreviated as MT), penetrant testing (abbreviated as PT), eddy current testing (abbreviated as ET). The unconventional nondestructive testing techniques are: acoustic emission (abbreviated as AE), infrared detection (abbreviated as IR), laser holographic detection (abbreviated as HNT) and the like.

[0010] The eddy current array technology is a new eddy current testing technology developed in recent years. Through the special design of the eddy current testing coil structure, and with the help of the powerful analysis, calculation and processing functions of the eddy current instrument and the matched computer, the material and the part are quickly and effectively detected, the inspection coverage area is large, the detection efficiency and the detection sensitivity are high.

[0011] However, the existing eddy current testing technology has the following problems:

[0012] The detection efficiency is low, the defect detection sensitivity is low, the operation is complex, the detection result is easy to be disturbed by the environment, a coupling agent is needed, the scanning mode is more single, the data analysis takes a long time, and the shape and circumferential position of the defect cannot be determined. SUMMARY

[0013] The present application provides an array probe for eddy current testing to solve the problems in the background art.

[0014] The present application provides an array probe for eddy current testing, which comprises a centering frame and a flat coil arranged in the middle of the centering frame in an array; wherein,

[0015] The flat coil comprises an excitation coil and a receiving coil;

[0016] The excitation coil is used for sending the eddy current for testing;

[0017] The receiving coil is used for receiving the feedback signal for testing.

[0018] In one embodiment of the present application: the receiving coil is divided into a first receiving coil, a second receiving coil and a third receiving coil when working;

[0019] The first receiving coil, the second receiving coil and the excitation coil perform axial detection;

[0020] The third receiving coil and the excitation coil perform circumferential detection.

[0021] In one embodiment of the present application, the signal generating circuit comprises a DA conversion chip, a first differential amplifier, a second differential amplifier, a third differential amplifier and a fourth differential amplifier.

[0022] The centering frame is internally provided with an FPGA logic programmable device, a signal generating circuit, a multiplexing circuit and a signal amplifying circuit; wherein,

[0023] The multiplexing circuit comprises a multiplexing sending circuit and a multiplexing receiving circuit, and a CPLD programmable device is arranged between the multiplexing sending circuit and the multiplexing receiving circuit;

[0024] The signal amplifying circuit comprises an eddy current differential amplifying circuit and an AD signal amplifying circuit;

[0025] The FPGA logic programmable device is electrically connected with the signal generating circuit, the output end of the signal generating circuit is electrically connected with the input end of the multiplexing sending circuit, and the FPGA logic programmable device is also electrically connected with the input end of the multiplexing receiving circuit;

[0026] The output end of the multiplexing sending circuit is electrically connected with the input end of the eddy current differential amplifying circuit;

[0027] The output end of the multiplexing receiving circuit is electrically connected with the input end of the AD signal amplifying circuit;

[0028] The signal generating circuit is used for generating an excitation signal source of an excitation coil;

[0029] The multiplexing circuit is used for multiplexing of multi-transmission and multi-reception;

[0030] The signal amplifying circuit is used for adjusting the transmission-reception gear of the excitation coil and a receiving coil.

[0031] In one embodiment of the present application, the signal generating circuit comprises a DA conversion chip, a first differential amplifier, a second differential amplifier, a third differential amplifier and a fourth differential amplifier; wherein,

[0032] The first differential amplifier and the second differential amplifier constitute a first differential amplifying circuit, and a first filter circuit is arranged between the first differential amplifier and the second differential amplifier and electrically connected;

[0033] The third differential amplifier and the fourth differential amplifier constitute a second differential amplifying circuit, and a second filter circuit is arranged between the third differential amplifier and the fourth differential amplifier and electrically connected.

[0034] In one embodiment of the present application, the multiplexing circuit comprises a double-power-source imitating switch, an instrument amplifier, a multiplexer and a radio frequency coaxial connector; wherein,

[0035] The output end of the multiplexer is electrically connected with the input end of the instrument amplifier, and the instrument amplifier is used for acquiring a defect signal;

[0036] The output end of the instrument amplifier is electrically connected with the input end of the double-power simulation switch, which is used for amplifying the excitation source signal;

[0037] The output end of the double-power simulation switch is electrically connected with the radio frequency coaxial connector.

[0038] In an embodiment of the present application: the signal amplification circuit comprises: a first amplifier, a second amplifier, a third amplifier, a fourth amplifier, a fifth amplifier, a sixth amplifier, a seventh amplifier, an eighth amplifier and a ninth amplifier; wherein,

[0039] The output end of the first amplifier and the input end of the second amplifier are electrically connected;

[0040] The output end of the second amplifier is respectively connected with the input end of the third amplifier, the fourth amplifier, the fifth amplifier and the sixth amplifier, thereby forming a plurality of flaw detection amplification output channels;

[0041] The output end of the third amplifier is respectively connected with the eighth amplifier and the seventh amplifier;

[0042] The input end of the eighth amplifier, the seventh amplifier, the fourth amplifier, the fifth amplifier and the sixth amplifier emits an eddy current signal through a shield shell driven flat coil; wherein,

[0043] A signal port is arranged on the shield shell.

[0044] The present application has the advantages that: the present application solves the problems of poor universality, high cost and low work efficiency of the existing eddy current probe scanning device; the internal multiplexing system of the present application greatly reduces the adverse effects of mutual inductance, and programs the actual time when each coil is excited to send its eddy current signal. In the detection process, the phase and frequency of the signal can determine the defect depth of the target object, and the amplitude of the signal can determine the amount of defect metal loss in the coil induction area; moreover, the closer to the transmitting coil, the higher the sensitivity, and the detection has directionality, realizing accurate detection.

[0045] Other features and advantages of the present application will be further described in the following specification, and some will become apparent from the specification, or will be understood from the practice of the present application. The purpose and other advantages of the present application can be achieved and obtained by the structure specifically pointed out in the written specification and the accompanying drawings.

[0046] The technical solutions of the present application will be further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0047] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0048] Figure 1 Figure 1 is a structural schematic diagram of an array probe using eddy current testing in an embodiment of the present application;

[0049] Figure 2 Figure 2 is a schematic diagram of the working principle of an array coil in an embodiment of the present application;

[0050] Figure 3 Figure 3 is a schematic diagram of the axial and circumferential directions in an embodiment of the present application;

[0051] Figure 4 Figure 4 is a schematic diagram of the angle of the axial and circumferential directions in an embodiment of the present application;

[0052] Figure 5 Figure 5 is a schematic diagram of the array arrangement of a coil in an embodiment of the present application;

[0053] Figure 6 Figure 6 is a timing pulse array diagram in an embodiment of the present application;

[0054] Figure 7 Figure 7 is a schematic diagram of the principle of a signal generating circuit in an embodiment of the present application;

[0055] Figure 8 Figure 8 is a schematic diagram of the principle of a multiplexing function in an embodiment of the present application;

[0056] Figure 9 Figure 9 is a schematic diagram of the amplification function in an embodiment of the present application;

[0057] Figure 10 Figure 10 is a schematic diagram of the internal circuit composition of a centering frame in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to explain and illustrate the present application, and are not used to limit the present application.

[0059] An array probe using eddy current testing comprises a centering frame and a flat coil arranged in the middle of the centering frame in an array manner; wherein,

[0060] The flat coil comprises an excitation coil and a receiving coil;

[0061] The excitation coil is used to send eddy current for testing;

[0062] The receiving coil is used to receive feedback signals for testing.

[0063] The principle of the above technical solution is that, as shown in Figure 1, the array probe using eddy current testing comprises a centering frame and a flat coil arranged in the middle of the centering frame in an array manner. Figure 1The present application is an array eddy current probe composed of multiple independent coils to solve the problems of poor versatility, high cost and low work efficiency of the existing eddy current probe scanning device. Figure 2 When the eddy current array data of the present application is multiplexed, the individual eddy current coils are excited at different times. Figure 4 The T1 and R3 coils of the present application constitute a circumferential detection unit.

[0064] The above technical solution has the advantages that the present application solves the problems of poor versatility, high cost and low work efficiency of the existing eddy current probe scanning device; the internal multiplexing system of the present application greatly reduces the adverse effects of mutual inductance, and programs the actual time when each coil is excited to send its eddy current signal.

[0065] In one embodiment of the present application, the receiving coil is divided into a first receiving coil, a second receiving coil and a third receiving coil when working.

[0066] The first receiving coil, the second receiving coil and the excitation coil perform axial detection.

[0067] The third receiving coil and the excitation coil perform circumferential detection.

[0068] The principle of the above technical solution is as follows: Figure 3 As shown in the accompanying drawings, when the probe of the present application works, in each time slot, one coil T1 acts as an excitation coil, and three coils (R1, R2 and R3) act as receiving coils. Figure 4 The array probe of the present application realizes 360° omnidirectional flaw detection function. Figure 5 The coil of the present application, wherein the lower row of coils has four solid color coils to realize phase and frequency control. ① The phase and frequency of the signal of the flat coil of the present application are related to the defect depth. ② The amplitude of the signal is related to the defect metal loss amount in the coil sensing area. ③ The closer to the transmission coil, the higher the sensitivity. ④ The detection has directionality.

[0069] The beneficial effects of the above technical solutions are that the application can realize directional detection and multi-directional high-density detection through axial detection and circumferential detection of different probes.

[0070] In an embodiment of the application:

[0071] The centering frame is internally provided with an FPGA logic programmable device, a signal generating circuit, a multiplexing circuit and a signal amplifying circuit; wherein,

[0072] The multiplexing circuit comprises a multiplexing sending circuit and a multiplexing receiving circuit, and a CPLD programmable device is arranged between the multiplexing sending circuit and the multiplexing receiving circuit;

[0073] The signal amplifying circuit comprises an eddy current differential amplifying circuit and an AD signal amplifying circuit;

[0074] The FPGA logic programmable device is electrically connected with the signal generating circuit, the output end of the signal generating circuit is electrically connected with the input end of the multiplexing sending circuit, and the FPGA logic programmable device is also electrically connected with the input end of the multiplexing receiving circuit;

[0075] The output end of the multiplexing sending circuit is electrically connected with the input end of the eddy current differential amplifying circuit;

[0076] The output end of the multiplexing receiving circuit is electrically connected with the input end of the AD signal amplifying circuit;

[0077] The signal generating circuit is used for generating an excitation signal source of an excitation coil;

[0078] The multiplexing circuit is used for multiplexing of multiple sending and multiple receiving;

[0079] The signal amplifying circuit is used for adjusting the transmission-reception gear of the excitation coil and a receiving coil.

[0080] The principle of the above technical solutions is that, as shown in the accompanying drawings, Figure 10The application is shown, a FPGA logic programmable device is used as a control body, a signal generating circuit is used as a signal source, a multiplexing sending circuit is used as a two-stage amplification end of the radio frequency signal of the eddy current probe, a plurality of eddy current probes are mainly due to the array arrangement of the flat coil, so that a plurality of eddy current signals are subjected to differential amplification for flaw detection, and the flaw detection signal is transmitted to the multiplexing receiving circuit through the AD signal amplification circuit and then transmitted to the FPGA logic programmable device.

[0081] The above technical scheme has the beneficial effects that the application uses the FPGA logic programmable device as the excitation source signal, obtains the excitation signal after differential filtering, realizes flaw detection, can support a plurality of signals in parallel, outputs excitation signals of different frequencies in the same cycle, and realizes flaw detection.

[0082] In an embodiment of the application, the signal generating circuit comprises a DA conversion chip U1, a first differential amplifier B1, a second differential amplifier B2, a third differential amplifier B3, and a fourth differential amplifier B4.

[0083] The first differential amplifier B1 and the second differential amplifier B2 constitute a first differential amplification circuit, and a first filter circuit is arranged between the first differential amplifier B1 and the second differential amplifier B2 and electrically connected.

[0084] The third differential amplifier B3 and the fourth differential amplifier B4 constitute a second differential amplification circuit, and a second filter circuit is arranged between the third differential amplifier B3 and the fourth differential amplifier B4 and electrically connected.

[0085] The principle of the above technical scheme is shown in the attached Figure 7 The signal generating circuit of the application preferably uses an AD9767ASTZ type chip to generate the excitation source signal, then uses two differential amplifiers to perform differential amplification, and obtains the excitation signal after filtering. In this process, the peak value can be tested by an oscilloscope, and the peak value of the excitation signal peak is kept at 1.76V in actual implementation.

[0086] The above technical scheme has the beneficial effects that

[0087] The signal generating circuit functions to differentially amplify and filter the excitation source signal, thereby improving stability of the excitation source signal.

[0088] In one embodiment of the present application, the multiplexing circuit comprises a dual power simulation switch U4, an instrument amplifier U3, a multiplexer U2 and a radio frequency coaxial connector S, wherein,

[0089] The output end of the multiplexer U2 is electrically connected with the input end of the instrument amplifier U3, which is used to acquire the defect signal;

[0090] The output end of the instrument amplifier U3 is electrically connected with the input end of the dual power simulation switch U4, which is used to amplify the excitation source signal;

[0091] The output end of the dual power simulation switch U4 is electrically connected with the radio frequency coaxial connector S.

[0092] The principle of the above technical solution lies in that, as shown in the accompanying drawings, Figure 8 the multiplexer of the present application realizes the functions of matrix type multi-transmission and multi-reception multiplexing which can be edited according to certain rules, such as 1 transmission and 3 reception, 2 transmission and 2 reception, 3 transmission and 1 reception, 4 transmission and 4 reception, and multi-channel self-transmission and self-reception. Then the signal is amplified by the instrument amplifier, and whether the amplified signal is transmitted or not is controlled by the dual power simulation switch U4, and the transmission unit is connected with the radio frequency coaxial connector S and the flat coil to transmit the flaw detection eddy current signal. Figure 6 The specific timing of the probe working and the minimum detection unit group operation form of the sensor can be embodied.

[0093] The above technical solution has the beneficial effects that the present application can realize the functions of multi-transmission and multi-reception multiplexing, and can realize amplification of the eddy current flaw detection signal, and control of transmission and reception of the flaw detection signal.

[0094] In one embodiment of the present application, the signal amplification circuit comprises a first amplifier D1, a second amplifier D2, a third amplifier D3, a fourth amplifier D4, a fifth amplifier D5, a sixth amplifier D6, a seventh amplifier D7 and an eighth amplifier D8, wherein,

[0095] The output end of the first amplifier D1 is electrically connected with the input end of the second amplifier D2;

[0096] The output end of the second amplifier D2 is respectively connected with the input end of the third amplifier D3, the fourth amplifier D4, the fifth amplifier D5 and the sixth amplifier D6, thereby constituting a plurality of flaw detection amplification output channels;

[0097] The output end of the third amplifier D3 is respectively connected with the seventh amplifier D7 and the eighth amplifier D8.

[0098] The input ends of the seventh amplifier D7, the eighth amplifier D8, the fourth amplifier D4, the fifth amplifier D5 and the sixth amplifier D6 emit the eddy current signal through the shield shell driving flat coil;

[0099] Wherein,

[0100] The shield shell is provided with a signal port.

[0101] The principle of the above technical solution is that, as shown in the accompanying drawings, Figure 9 As shown in the accompanying drawings, the present application realizes the emission of the excitation source in the form of square wave and differential mode. When the gear position is adjusted, the square wave is composed of long and short pulses, the length of the single short pulse is microsecond level (not more than 10us), and the length of the long pulse is 10 times or more than that of the short pulse. The long pulse is used for resetting (starting again), and the short pulse is used for jumping (moving one unit). Therefore, the signal amplification circuit realizes the emission of square wave with different pulse lengths through different amplification signal paths, and further realizes the gear position adjustment.

[0102] The beneficial effects of the above technical solution are that the present application realizes the generation of pulse signal through the repeated amplification of multiple amplifiers, realizes the emission of pulse signal through the square wave composed of pulse signal, and further realizes the fast and accurate gear position adjustment during the flaw detection.

[0103] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and the equivalent technology, the present application also intends to include these modifications and variations.

Claims

1. An array probe utilizing eddy current flaw detection, characterized in that, It consists of a centering frame and flat coils arranged in an array in the middle of the centering frame; wherein, The flat coil includes an excitation coil and a receiving coil. When the receiving coil is in operation, it is divided into a first receiving coil, a second receiving coil, and a third receiving coil. The first receiving coil, the second receiving coil, and the excitation coil perform axial detection; The third receiving coil and the excitation coil perform circumferential detection; The centering frame includes a multiplexing circuit, which comprises a dual-supply analog switch (U4), an instrumentation amplifier (U3), a multiplexer (U2), and an RF coaxial connector (S); among which, The output of the multiplexer (U2) is electrically connected to the input of the instrumentation amplifier (U3), which is used to acquire defect signals; The output of the instrumentation amplifier (U3) is electrically connected to the input of the dual-power analog switch (U4), which is used to amplify the excitation source signal; The output of the dual-power analog switch (U4) is electrically connected to the RF coaxial connector (S); The excitation coil is used to send eddy currents for flaw detection; The receiving coil is used to receive flaw detection feedback signals.

2. An array probe for eddy current flaw detection as described in claim 1, characterized in that, The centering frame contains an FPGA programmable logic device, a signal generation circuit, and a signal amplification circuit; among them, The multiplexing circuit includes a multiplexing transmitting circuit and a multiplexing receiving circuit, with a CPLD programmable device disposed between the multiplexing transmitting circuit and the multiplexing receiving circuit; The signal amplification circuit includes an eddy current differential amplifier circuit and an AD signal amplification circuit; The FPGA logic programmable device is electrically connected to the signal generation circuit, the output of the signal generation circuit is electrically connected to the input of the multiplexed transmitting circuit, and the FPGA logic programmable device is also electrically connected to the input of the multiplexed receiving circuit. The output of the multiplexed transmitting circuit is electrically connected to the input of the eddy current differential amplifier circuit; The output of the multiplexed receiving circuit is electrically connected to the input of the AD signal amplification circuit; The signal generation circuit is used to generate the excitation signal source for the excitation coil; Multiplexing circuits are used for multiplexing multiplexed signals; The signal amplification circuit is used to adjust the transmit-receive settings of the excitation coil and the receiving coil.

3. An array probe for eddy current flaw detection as described in claim 2, characterized in that, The signal generation circuit includes a DA converter chip (U1), a first differential amplifier (B1), a second differential amplifier (B2), a third differential amplifier (B3), and a fourth differential amplifier (B4); wherein, The first differential amplifier (B1) and the second differential amplifier (B2) constitute a first differential amplifier circuit, and a first filter circuit is electrically connected between the first differential amplifier (B1) and the second differential amplifier (B2). The third differential amplifier (B3) and the fourth differential amplifier (B4) constitute the second differential amplifier circuit, and the second differential amplifier circuit is provided between the third differential amplifier (B3) and the fourth differential amplifier (B4).

4. An array probe for eddy current flaw detection as described in claim 2, characterized in that, The signal amplification circuit includes: a first amplifier (D1), a second amplifier (D2), a third amplifier (D3), a fourth amplifier (D4), a fifth amplifier (D5), a sixth amplifier (D6), a seventh amplifier (D7), and an eighth amplifier (D8); wherein, The output terminal of the first amplifier (D1) and the input terminal of the second amplifier (D2) are electrically connected; The output of the second amplifier (D2) is connected to the input of the third amplifier (D3), the fourth amplifier (D4), the fifth amplifier (D5), and the sixth amplifier (D6) respectively, forming multiple flaw detection amplification output channels; The output of the third amplifier (D3) is connected to the seventh amplifier (D7) and the eighth amplifier (D8) respectively; The input terminals of the seventh amplifier (D7), eighth amplifier (D8), fourth amplifier (D4), fifth amplifier (D5), and sixth amplifier (D6) drive flat coils through shielding shells to generate eddy current signals; among them, The shielding shell is equipped with a signal port.

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