CN111351843A - Eddy current multiplexing array probe for BOBBIN coil excitation point type coil receiving - Google Patents

Eddy current multiplexing array probe for BOBBIN coil excitation point type coil receiving Download PDF

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Publication number
CN111351843A
CN111351843A CN201811578624.6A CN201811578624A CN111351843A CN 111351843 A CN111351843 A CN 111351843A CN 201811578624 A CN201811578624 A CN 201811578624A CN 111351843 A CN111351843 A CN 111351843A
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China
Prior art keywords
coil
eddy current
type coil
probe
bobbin
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CN201811578624.6A
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Inventor
邵文斌
祁攀
郑德旭
崔洪岩
廖述圣
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Research Institute of Nuclear Power Operation
China Nuclear Power Operation Technology Corp Ltd
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Research Institute of Nuclear Power Operation
China Nuclear Power Operation Technology Corp Ltd
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Priority to CN201811578624.6A priority Critical patent/CN111351843A/en
Publication of CN111351843A publication Critical patent/CN111351843A/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/90Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
    • G01N27/9006Details, e.g. in the structure or functioning of sensors

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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
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  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

Abstract

The invention relates to an eddy current multiplexing array probe received by a BOBBIN coil excitation point type coil, which comprises a small disc type coil, a probe framework and a large axial winding type coil; the probe framework is of a hollow cylindrical structure, and a circle of circular grooves which are densely arranged are formed in the circumferential direction of the inner surface of the probe framework and used for placing the small disc type coil; a circumferential groove which is positioned above the circle of circular groove is processed on the outer surface of the circular groove and is used for placing a large-axis winding type coil; a probe framework material interval with a certain thickness is arranged between the circular groove and the circumferential groove; the small disc type coil is used for signal pickup; the large-axis winding type coil is used for exciting signals. The large axial-wound coil is positioned right above the disc coil, so that a stray-free strong magnetic field is directly applied to a detection area, and meanwhile, the small disc coil receives the strongest signal of defect disturbance, so that the defect detection is facilitated, and the defect detection sensitivity is improved.

Description

Eddy current multiplexing array probe for BOBBIN coil excitation point type coil receiving
Technical Field
The invention belongs to the field of eddy current nondestructive inspection of non-ferromagnetic heat transfer tubes of heat exchangers, and particularly relates to an eddy current multiplexing array probe for receiving by a BOBBIN coil excitation point type coil.
Background
Heat exchangers are important components of heat conversion systems in various industries, and heat transfer tubes are heat transfer media and pressure boundaries of heat exchangers, and the integrity of the heat transfer tubes is critical to the normal operation of the heat exchangers. However, during the manufacturing and using processes of the heat transfer tube, various types of defects are often generated due to differences in the material, design structure, processing technology and operation conditions of the tube.
The nondestructive inspection of heat transfer tubes of heat exchangers generally uses an eddy current inspection method. The axial-wound coil probe is widely used, the self-receiving technology (exciting an electromagnetic field by the coil and receiving the electromagnetic field fed back by a detected object) is adopted by the axial-wound coil, the axial-wound probe has high sensitivity on axial linear defects and circular defects of the inner wall and the outer wall of the heat transfer pipe, and the defects can be timely and accurately found and quantified. However, for small and narrow circumferential defects, the direction is parallel to the direction of the electromagnetic field excited by the wound coil, so that the wound probe is difficult to find. Meanwhile, in the areas of the supporting plate and the tube plate, particularly the latter, structure signals are complex, and multiple structure signals such as tube expansion, tube plates and the like exist, so that electromagnetic induction is distorted in the area, and if defects appear in the area, the detection is easy to miss, and a detection blind area appears. In response to this situation, new technologies, namely eddy current rotating probe technology (small wound coils mechanically rotated for inspection purposes) and array probe technology, are beginning to be used in evaporator eddy current testing domestically and abroad. However, the inspection speed of the rotary probe is a bottleneck restricting the wide application of the probe, and the array probe not only has the detection efficiency of the eddy current shaft-wound probe, but also has the defect qualitative capability of the rotary probe.
At present, the eddy current array probe (see fig. 1) applied to engineering practice adopts a transceiving technology (one coil excites an electromagnetic field, and the other coil or coils receive the electromagnetic field fed back by a detected object), two rows or three rows of small flat coil groups are arranged in the circumferential direction of a probe main body, a distance is reserved between each row of small flat coil groups, the coils of each row are arranged in a crossed manner, and eddy current signals are excited and received in a time-sharing manner through a multiplexing technology, so that the purpose of electromagnetic field rotation is achieved, and the eddy current array probe is used for eddy current inspection. In the practical application process of the probe, the detection efficiency and the sensitivity can be ensured, but the problems also exist, namely the more the number of the coils is, the greater the manufacturing difficulty is, the greater the damage probability is, and in addition, the defect can not be quantified by the array probe. To address these problems, this patent designs a multiplexed array probe structure that is excited with eddy current wound coils.
The large axial winding type coil (taking a probe body as an axis) is used as an excitation source, the plurality of small axial winding type coils (placed in the circumferential direction of the probe body) are used as excitation and receiving sources, the rotation of an electromagnetic field is realized through a multiplexing technology, and the heat transfer defect detection capability is achieved.
Disclosure of Invention
The invention aims to: the eddy current array probe solves the problems that the number of coils of a conventional eddy current array probe is large, the manufacturing difficulty is high, the damage probability is high and the like. The design of the probe aims to reduce the design and manufacturing difficulty of the probe, shorten the manufacturing period of the probe, reduce the number of coils of the probe, reduce the damage probability of the probe and prolong the service life of the probe.
The technical scheme of the invention is as follows: an eddy current multiplexing array probe received by a BOBBIN coil excitation point type coil comprises a small disc type coil, a probe framework and a large axial winding type coil;
the probe framework is of a hollow cylindrical structure, and a circle of circular grooves which are densely arranged are formed in the circumferential direction of the inner surface of the probe framework and used for placing the small disc type coil; a circumferential groove which is positioned above the circle of circular groove is processed on the outer surface of the circular groove and is used for placing a large-axis winding type coil; a probe framework material interval with a certain thickness is arranged between the circular groove and the circumferential groove;
the small disc type coil is used for signal pickup;
the large-axis winding type coil is used for exciting signals.
Furthermore, the outer diameter of the probe framework is 10-25mm, and the thickness of the probe framework is 4-8 mm.
Further, the thickness between the circular groove and the circumferential groove is 0.5-1 mm.
Furthermore, the circular groove is 1.5-4.5mm, and the width of the circumferential groove is 1-3 mm.
Furthermore, the probe framework is made of PEEK materials.
Furthermore, the small disc type coil is made of a copper enameled wire.
Furthermore, the large axial winding type coil is made of a copper enameled wire.
Furthermore, when the large wound coil works in a self-generating and self-receiving mode, the large wound coil is an exciting part and a receiving part, under the mode, when stable alternating current is introduced into the large wound coil, eddy current is generated in the circumferential direction of the detected heat transfer pipe, if axial defects exist, the large wound coil can generate disturbance on a circumferential eddy current field induced on the pipe wall of the coil, so that the circumferential eddy current field is changed, the large wound coil is received, converted, analyzed and processed by an eddy current instrument in an electric signal form, and the axial defects are judged according to information such as the phase and amplitude of the signals.
Further, when a large-axis winding coil is used for excitation, and a small disc coil receives the large-axis winding coil, because the excitation current introduced into the large-axis winding coil is large, the generated eddy field intensity is high, the disturbance eddy current signal received in the small disc coil is correspondingly increased, when the small disc coil which is densely distributed in the circumferential direction is sequentially triggered by adopting a multi-way switch, the signal in the small disc coil is picked up, output to a multiplexing circuit for multiplexing and amplification, then input to an eddy current instrument for processing, and the circumferential defect is judged according to the phase and amplitude information of the signal.
The invention relates to a using method of an eddy current multiplexing array probe received by a BOBBIN coil excitation point type coil, which comprises the following steps:
step one, a steady-state sinusoidal excitation current is introduced into a BOBBIN coil, the steady-state sinusoidal excitation current can generate an alternating magnetic field, eddy currents can be induced inside a tubular structure to be detected placed in the alternating magnetic field, secondary magnetic fields can be induced by the alternating eddy currents, a composite magnetic field formed by superposing the two magnetic fields can enable two ends of a disc type coil to generate voltage signals, the voltage signals are influenced by different defect forms inside the tubular structure to be detected, the induced secondary magnetic fields can also generate corresponding changes, and then different voltage signals are generated. When the probe returns to collect signals, the disc coils are sequentially excited and receive signals through time sequence control, and defects along the direction of the pipe shaft are effectively detected.
And step two, when the probe pulls back the acquired signal, only exciting and receiving the disc coils, separating two disc coils of one disc coil in the middle as an exciting and detecting unit group, and controlling the operation of one exciting and receiving group in a time sequence manner so as to realize detection of circumferential defects.
The invention has the following remarkable effects:
1) in the traditional array probe, each small shaft-wound coil is excited in a time-sharing mode, but the impedance and the structure of each coil are different, the generated eddy current field is not uniform, and the detection sensitivity in each direction is inconsistent. A large-axis winding type coil is used as an excitation source, only one coil is used for excitation, and the generated eddy current field is more stable and consistent;
2) the large winding type coil is used as an excitation source, a row of small winding type coils is reduced, the number of the coils is reduced, the difficulty of manufacturing the probe is reduced, meanwhile, the probability of damage of the probe is reduced, and the service life of the probe is prolonged;
3) the large-axis winding type coil can be used independently, the found defects can be quantified, and the detection sensitivity of the detectable defects is improved;
4) the large axial winding type coil is positioned right above the disc type coil, so that a non-stray strong magnetic field is directly applied to a detection area, and meanwhile, the strongest signal of defect disturbance received by the small disc type coil is beneficial to defect detection and improves the detection sensitivity of the defects.
Drawings
FIG. 1 is a schematic diagram of a conventional eddy current array probe coil arrangement;
FIG. 2 is a schematic diagram of an array probe;
in the figure: 1-small disc coil, 2-probe framework and 3-large axis coil.
Detailed Description
The following describes an eddy current multiplexing array probe for BOBBIN coil excitation point type coil reception according to the present invention in further detail with reference to the accompanying drawings and embodiments.
As shown in fig. 1-2, an eddy current multiplexing array probe for receiving by a BOBBIN coil excitation point type coil comprises a small disc type coil 1, a probe framework 2 and a large axial winding type coil 3;
the probe framework 2 is of a hollow cylindrical structure, and a circle of circular grooves which are densely arranged are formed in the circumferential direction of the inner surface of the probe framework and used for placing the small disc coils 1; a circumferential groove which is positioned above the circle of circular groove is processed on the outer surface of the circular groove and is used for placing the large-axis winding type coil 3; a certain thickness of material interval of the probe framework 2 is arranged between the circular groove and the circumferential groove;
the small disc type coil 1 is used for signal pickup;
the large winding type coil 3 is used for exciting signals.
Furthermore, the outer diameter of the probe framework 2 is 10-25mm, and the thickness is 4-8 mm.
Further, the thickness between the circular groove and the circumferential groove is 0.5-1 mm.
Furthermore, the circular groove is 1.5-4.5mm, and the width of the circumferential groove is 1-3 mm.
Furthermore, the probe framework 2 is made of PEEK material.
Furthermore, the small disc type coil 1 is made of a copper enameled wire.
Further, the large winding coil 3 is made of a copper enameled wire.
Furthermore, when the large wound coil 3 operates in a self-generating and self-receiving mode, it is both an excitation part and a receiving part, in this mode, when a stable alternating current is introduced into the large wound coil 3, an eddy current is generated in the circumferential direction of the heat transfer pipe to be detected, if an axial defect exists, it will generate disturbance to the circumferential eddy current field induced by the coil on the pipe wall, so that it changes, and is received, converted, analyzed and processed by the eddy current instrument in the form of an electrical signal, and the determination of the axial defect is performed through the information of the phase and amplitude of the signal.
Further, when the large axial winding type coil 3 is used for excitation, and the small disc type coil 1 receives, because the excitation current introduced into the large axial winding type coil 3 is large, the generated eddy field intensity is high, the disturbance eddy current signal received in the small disc type coil 1 is correspondingly increased, when the small disc type coil 1 which is densely distributed in the circumferential direction is sequentially triggered by adopting a multi-way switch, the signal in the small disc type coil 1 is picked up, the signal is output to a multiplexing circuit for multiplexing and amplification, then the signal is input to an eddy current instrument for processing, and the circumferential defect is judged according to the phase and amplitude information of the signal.
The invention relates to a using method of an eddy current multiplexing array probe received by a BOBBIN coil excitation point type coil, which comprises the following steps:
step one, a steady-state sinusoidal excitation current is introduced into a BOBBIN coil, the steady-state sinusoidal excitation current can generate an alternating magnetic field, eddy currents can be induced inside a tubular structure to be detected placed in the alternating magnetic field, secondary magnetic fields can be induced by the alternating eddy currents, a composite magnetic field formed by superposing the two magnetic fields can enable the two ends of the disc coil 1 to generate voltage signals, the induced secondary magnetic fields can generate corresponding changes under the influence of different defect forms inside the tubular structure to be detected, and then different voltage signals can be generated. When the probe returns to collect signals, the disc coil 1 is sequentially excited and receives the signals through time sequence control, so that the defects along the direction of the pipe shaft can be effectively detected.
And step two, when the probe pulls back the acquired signal, only exciting and receiving the disc coil 1, separating two disc coils of one disc coil in the middle as an exciting and detecting unit group, and controlling the operation of the exciting and receiving group by time sequence so as to realize detection of circumferential defects.

Claims (10)

1. A BOBBIN coil excitation point type coil received eddy current multiplexing array probe is characterized in that: comprises a small disc type coil (1), a probe framework (2) and a large axis winding type coil (3);
the probe framework (2) is of a hollow cylindrical structure, and a circle of circular grooves which are densely arranged are formed in the circumferential direction of the inner surface of the probe framework and used for placing the small disc type coil (1); a circumferential groove which is positioned above the circle of circular groove is processed on the outer surface of the circular groove and is used for placing a large-axis winding type coil (3); a material interval of the probe framework (2) with a certain thickness is arranged between the circular groove and the circumferential groove;
the small disc type coil (1) is used for signal pickup;
the large winding type coil (3) is used for exciting signals.
2. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: the outer diameter of the probe framework (2) is 10-25mm, and the thickness is 4-8 mm.
3. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: the thickness between the circular groove and the circumferential groove is 0.5-1 mm.
4. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: the circular groove is 1.5-4.5mm, and the circumferential groove is 1-3mm in width.
5. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: the probe framework (2) is made of PEEK materials.
6. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: the small disc type coil (1) is made of a copper enameled wire.
7. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: the large axial winding type coil (3) is made of a copper enameled wire.
8. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: when the large winding type coil (3) works in a self-generating and self-receiving mode, the large winding type coil is an exciting part and a receiving part, under the mode, when stable alternating current is introduced into the large winding type coil (3), eddy current is generated in the circumferential direction of a detected heat transfer pipe, if axial defects exist, the eddy current generates disturbance on a circumferential eddy current field induced on the pipe wall of the coil, the circumferential eddy current field is changed, the circumferential eddy current field is received, converted, analyzed and processed by an eddy current instrument in an electric signal mode, and the axial defects are judged according to information such as the phase and amplitude of the signals.
9. The BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, wherein: when the large-axis winding type coil (3) is used as excitation and the small disc type coil (1) is used for receiving, because the excitation current introduced into the large-axis winding type coil (3) is large, the generated eddy field intensity is high, the disturbance eddy current signal received in the small disc type coil (1) is correspondingly increased, when the small disc type coil (1) which is densely distributed in the circumferential direction is sequentially triggered by adopting a multi-way switch, the signal in the small disc type coil (1) is picked up, the signal is output to a multiplexing circuit for multiplexing and amplification, then the signal is input to an eddy current instrument for processing, and the circumferential defect is judged according to the phase and amplitude information of the signal.
10. The method of using a BOBBIN coil excitation point coil received eddy current multiplexed array probe of claim 1, comprising the steps of:
step one, a stable sine excitation current is introduced into a BOBBIN coil, the stable sine excitation current can generate an alternating magnetic field, eddy currents can be induced in a tubular structure to be detected placed in the alternating magnetic field, secondary magnetic fields can be induced by the alternating eddy currents, a composite magnetic field formed by superposition of the two magnetic fields can enable voltage signals to be generated at two ends of the disc coil (1), the voltage signals are influenced by different defect forms in the tubular structure to be detected, the induced secondary magnetic fields can correspondingly change, and then different voltage signals are generated. When the probe returns to collect signals, the disc coil (1) is sequentially excited and receives the signals through time sequence control, so that the defects along the direction of the tube shaft can be effectively detected.
And step two, when the probe pulls back the acquired signal, only excitation and receiving processing is carried out on the disc coil (1), two disc coils with one disc coil in the middle are used as an excitation and detection unit group, and the work of the excitation and reception group is controlled through time sequence, so that the detection of the circumferential defect is realized.
CN201811578624.6A 2018-12-24 2018-12-24 Eddy current multiplexing array probe for BOBBIN coil excitation point type coil receiving Pending CN111351843A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114062486A (en) * 2021-11-12 2022-02-18 中广核检测技术有限公司 Sensor for eddy current detection of fingerstall tube of nuclear power station

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4808927A (en) * 1987-02-19 1989-02-28 Atomic Energy Of Canada Limited Circumferentially compensating eddy current probe with alternately polarized receiver coil
JPH06273385A (en) * 1992-09-29 1994-09-30 Japan Atom Energy Res Inst Probe and method for eddy current flaw detection in metal pipe
JP2000235019A (en) * 1999-02-12 2000-08-29 Genshiryoku Engineering:Kk Eddy-current flaw detecting probe
US20130214771A1 (en) * 2012-01-25 2013-08-22 Radiation Monitoring Devices, Inc. Systems and methods for inspecting structures including pipes and reinforced concrete
CN105806934A (en) * 2014-12-30 2016-07-27 中核武汉核电运行技术股份有限公司 Array probe for eddy current multiplexing
CN210155076U (en) * 2018-12-24 2020-03-17 核动力运行研究所 Eddy current array probe for receiving axial coil excitation point type coil

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4808927A (en) * 1987-02-19 1989-02-28 Atomic Energy Of Canada Limited Circumferentially compensating eddy current probe with alternately polarized receiver coil
JPH06273385A (en) * 1992-09-29 1994-09-30 Japan Atom Energy Res Inst Probe and method for eddy current flaw detection in metal pipe
JP2000235019A (en) * 1999-02-12 2000-08-29 Genshiryoku Engineering:Kk Eddy-current flaw detecting probe
US20130214771A1 (en) * 2012-01-25 2013-08-22 Radiation Monitoring Devices, Inc. Systems and methods for inspecting structures including pipes and reinforced concrete
CN105806934A (en) * 2014-12-30 2016-07-27 中核武汉核电运行技术股份有限公司 Array probe for eddy current multiplexing
CN210155076U (en) * 2018-12-24 2020-03-17 核动力运行研究所 Eddy current array probe for receiving axial coil excitation point type coil

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114062486A (en) * 2021-11-12 2022-02-18 中广核检测技术有限公司 Sensor for eddy current detection of fingerstall tube of nuclear power station

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