CN105044202A - Detection system and method based on saddle-shaped open binary channel vortex probe - Google Patents
Detection system and method based on saddle-shaped open binary channel vortex probe Download PDFInfo
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- CN105044202A CN105044202A CN201510424844.3A CN201510424844A CN105044202A CN 105044202 A CN105044202 A CN 105044202A CN 201510424844 A CN201510424844 A CN 201510424844A CN 105044202 A CN105044202 A CN 105044202A
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Abstract
The invention discloses a detection system and method based on a saddle-shaped open binary channel vortex probe. The detection system is characterized by comprising a control module, a signal processing module and a probe. The probe is a saddle-shaped open binary channel vortex probe, which comprises a concave arc surface; the probe is equipped with an excitation coil and four detection coils; the four detection coils are divided into two groups, and arranged on separate sides of the excitation coil; the excitation coil and four detection coils are wound around the five core coils respectively; the signal processing module includes a signal generator, an amplification circuit, a phase-sensitive detection circuit and a rectification filter circuit; and the output signals of the detection coils are successively treated by the amplification circuit, the phase-sensitive detection circuit and the rectification filter circuit and enters into the control module. The detection system and method based on saddle-shaped open binary channel vortex probe can be used in vortex detection of elbow part of the hot surface pipe with two closed ends, and have the advantages of easy operation and practicality.
Description
Technical field
The invention belongs to technical field of nondestructive inspection, relate to a kind of detection system based on the open double-channel vortex probe of the shape of a saddle and method.
Background technology
Boiler of power plant weldless steel tube is mainly used to manufacture the important Electric Power Generating Equipment such as water screen tube, overheated steam pipe, reheating steam pipe, economizer tube, in order to ensure the safe and stable operation of electrical production, need to carry out planned detection and maintenance to power equipment, the restriction of examined environment and testing conditions, adopts more conveniently detection method of eddy to carry out Non-Destructive Testing to seamless steel tube for boiler usually.
EDDY CURRENT is applicable to the Non-Destructive Testing of metallic conductor surface and near surface flaw, is widely used in detection practice.Eddy current probe is the key components of eddy-current nondestructive detection system, has conclusive influence to detection system performance.Magnetic test coil has through mode, sonde-type and plug-in type etc. three kinds usually, and the inwall that tube base coil is applicable to pipe fitting or pipeline detects; Probe coil is applicable to carry out partial detection to test specimen; Feed-through coil is generally used for carrying out Non-Destructive Testing to the defect on metal pipe bar surface or nearly surface.But when adopting feed-through coil detection mode to carry out nondestructive examination, what coil covered is pipe, rod or the circumference of wire rod the preceding paragraph length, the information obtained is the accumulation results of influence factor on whole annulus, cannot judge particular location circumferentially residing for defect, in addition, in some particular application, as for the detection of power plant boiler with pipe with small pipe diameter steel pipe (external diameter < 100mm), because penstock installation is tight, detection space is narrow and small, and feed-through coil method has been difficult to detection operation.
Chinese patent " recognition methods (application number: 200810055891.5; publication number; CN101216460A) based on the Magnetic Flux Leakage Inspecting inside and outside wall defect of alternating current-direct current resultant magnetization " relate to a kind of steel pipe inside and outside defect detecting technique, the Division identification of steel pipe inside and outside wall defect can be realized, but the method is placed in by sensor inside tube wall to carry out EDDY CURRENT, is not suitable for the Non-Destructive Testing of the in-service heating surface tubes in boilers of closed at both ends.Chinese patent " a kind of heating surface tube detection eddy current probe (application number: 201220205052.9, publication number, CN202583124U) " a kind of eddy current probe that can carry out through mode EDDY CURRENT to Power Station Boiler Heating Surface pipe is related to, be made up of the collated band in two semicircle coil and annular framed bent inwall, closed heating surface tube can be inserted in detect, but the method only can detect by the straight length larger to layout gap, the eddy current test of elbow cannot be realized, and the elbow of heating surface tubes in boilers normally stress concentration portion position, simultaneously, under the effect of high-temperature flue gas and water vapor, also be oxidation occurs and corrodes the most serious position, belong to emphasis and detect position.
Therefore, be necessary to design a kind of detection system based on the open double-channel vortex probe of the shape of a saddle and method.
Summary of the invention
Technical matters to be solved by this invention is to provide a kind of detection system based on the open double-channel vortex probe of the shape of a saddle and method, the EDDY CURRENT of the bend part of the hot side pipe of closed at both ends should can be used for based on the detection system of the open double-channel vortex probe of the shape of a saddle and method, easy to operate, practical.
The technical solution of invention is as follows:
Based on a detection system for the open double-channel vortex probe of the shape of a saddle, comprise control module, signal processing module and probe;
Described probe is the open double-channel vortex probe of the shape of a saddle, and probe has a recessed arc surface, is provided with 1 drive coil and 4 magnetic test coils in probe; A 4 magnetic test coils between two component are 2 groups, and the both sides of the drive coil that is placed in; 1 drive coil and 4 magnetic test coils install around respectively on 5 iron-core coils;
Signal processing module comprises signal generator, amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit;
When detecting body to be detected, be placed on body to be detected by probe, the arc surface of probe presses close to the outer wall of body;
Signal generator is controlled by control module, and the output signal of signal generator is carried on drive coil;
The output signal of magnetic test coil enters control module successively after amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit process.
Two groups of magnetic test coils are symmetrically distributed in drive coil both sides, and 2 magnetic test coils often organized in magnetic test coil adopt differential type connected mode.
It is the oscillator signal of 10KHz ~ 500KHz that signal generator produces frequency range.
The described detection system based on the open double-channel vortex probe of the shape of a saddle also comprises the display module be connected with control module.
Display module is double screen, binary channels display module.
Iron-core coil forms by the siliconized plate that multi-disc 0.2 ~ 0.5mm is thick is stacked.
The shape of a saddle open double-channel vortex probe is on the whole for having the saddle type structure of a recessed arc surface, and described recessed arc surface is used for suitable with the circular arc outer wall of pipe or cylindrical UUT;
The open double-channel vortex probe of the shape of a saddle comprises shell and 1 drive coil arranged in the enclosure and 4 magnetic test coils; A 4 magnetic test coils between two component are 2 groups, and the both sides of the drive coil that is placed in; 1 drive coil and 4 magnetic test coils install around respectively on 5 iron-core coils.Recessed arc surface is positioned on shell.
Based on a detection method for the open double-channel vortex probe of the shape of a saddle, adopt aforesaid detection system examinations;
Be placed on body to be detected by probe, the arc surface of probe presses close to the outer wall of body;
By the drive coil of popping one's head in, magnetic field is loaded on body to be detected, gathered by the feedback signal of group magnetic test coil of two in eddy current probe to detected object and body to be detected, the signal of collection enters control module successively and processes after amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit process again.
During detection, probe is moved along body, in moving process, collect feedback signal, realize the surface defect detection to straight tube or bend pipe.
Control module and signal processing module are by RS232 interface communication.
Probe for saddle type structure, has a recessed arc surface.Have three parallel grooves in probe, middle groove is used for preventing drive coil, and the groove of both sides is respectively used to placement 2 groups of magnetic test coils.
There are three parallel grooves, the bearing of trend of groove and the axes normal of arc surface in probe; Middle groove is used for preventing drive coil, and the groove of both sides is respectively used to placement 2 groups of magnetic test coils.
Eddy current probe is made up of one group of drive coil and two groups of magnetic test coils, has the advantages that sensing range is large and detection sensitivity is high.
Signal processing module can amplify the signal of eddy current probe feedback, detection and filtering process.
Signal generator can provide high-frequency oscillation signal for eddy current probe drive coil, and frequency range can reach 10KHz ~ 500KHz, has wider frequency range.
Phase-sensitive detection circuit can lower the impact of leakage field on testing result of fault location effectively.
The major function of phase-sensitive detection circuit: (1) suppresses undesired signal; (2) judgment signal phase place and frequency.Have half-wave phase-sensitive detector (PSD) and all-wave phase-sensitive detector (PSD), what this patent adopted is a kind of digital all-wave phase-sensitive detection circuit, and as shown in Figure 8, phase sensitive detection is current mature technology to circuit theory diagrams.
In figure, u
rt () is reference signal, the u of the output after shaping circuit
1t () is and measured signal u
st () is with the square wave of frequency, homophase.This square-wave signal controls field effect transistor 3DJ16 thus controls the action of electronic switch, determines field effect transistor drain signal u
1(t).Difference puts A2 to signal u
3and u
ssynthesize, obtain outputing signal u
0.
When field effect transistor is ended, amplifier A2 is operated in following state; When field effect transistor conducting, A2 is operated in anti-phase magnifying state.
Control and display module, for data processing and display, notebook computer can be adopted, there is double screen binary channels display interface, be respectively used to the detection feedback signal of display two groups of differential readout coils, signal frequency, waveform phase angle, the isoparametric adjustment of signal gain can be realized, and can calculate testing result and store.
Described eddy current probe drive coil and magnetic test coil, iron-core coil adopts the silicon steel plate packing that 0.2 ~ 0.5mm is thick, and siliconized plate front end is cambered surface, effectively can increase excitation field, improves detection sensitivity.Concrete, can 0.2mm be adopted, the thickness of 0.3mm, 0.35mm and 0.5mm.
The top of siliconized plate is the arc with the indent of described arc surface adaptation; The both sides of siliconized plate have the breach for coiling, the siliconized plate of the iron core that drive coil is corresponding is of a size of: width 24mm (i.e. base length), and the degree of depth of breach is 2mm, and gap width is 9mm, bottom is 14mm to camber line lowest part, and top has the chamfering that radius is 0.5mm.
The siliconized plate of the iron core that detecting coil is corresponding is of a size of: width 15mm (i.e. base length), and the degree of depth of breach is 2mm, and gap width is 8mm, and bottom is 13mm to camber line lowest part, and top has the chamfering that radius is 0.5mm.
System comprises control and display module, signal processing module and eddy current probe, and wherein signal processing module comprises signal generator, amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit.
Signal generator generation high-frequency oscillation signal is transferred to the drive coil in eddy current probe, magnetic field is loaded on detected object, the feedback signal of magnetic test coil to detected object connected by group differential type of two in eddy current probe again gathers, the signal that signal processing module feeds back eddy current probe amplifies, detection and filtering process, data export to control and display module by RS232 interface, carry out shuangping san, calculating and storage to testing result.The present invention has higher accuracy in detection, sensitivity and stronger antijamming capability, and volume is little, easy to operate, and surface and the near surface flaw that can be applicable to power plant's heating surface tube bend part detect.
The top of siliconized plate is the arc with the indent of described arc surface adaptation; The both sides of siliconized plate have the breach for coiling, the siliconized plate of the iron core that drive coil is corresponding is of a size of: width 24mm (i.e. base length), and the degree of depth of breach is 2mm, and gap width is 9mm, bottom is 14mm to camber line lowest part, and top has the chamfering that radius is 0.5mm.
The siliconized plate of the iron core that detecting coil is corresponding is of a size of: width 15mm (i.e. base length), and the degree of depth of breach is 2mm, and gap width is 8mm, and bottom is 13mm to camber line lowest part, and top has the chamfering that radius is 0.5mm.
Beneficial effect:
In detection system based on the open double-channel vortex probe of the shape of a saddle of the present invention, two groups of magnetic test coils of two groups of eddy current probes are symmetric in drive coil both sides, are differential type connected mode, and twin coil binary channels effectively can improve the accuracy of detection.
Described detection probe is the open eddy current probe of the shape of a saddle, and the magnetic test coil be connected with two groups of differential types by one group of drive coil forms, and two groups of magnetic test coils are symmetric in drive coil both sides, and sensing range covers whole probe arc surface.
Described coil all comprises iron core, and iron-core coil adopts the silicon steel plate packing that 0.2 ~ 0.5mm is thick, and siliconized plate front end is cambered surface, effectively can increase excitation field.
Described signal generator can provide high-frequency oscillation signal for eddy current probe drive coil, frequency range can reach 10KHz ~ 500KHz, the high-frequency oscillation signal produced is transferred to the drive coil in eddy current probe, by drive coil, magnetic field is loaded on detected object, then is gathered by the feedback signal of group magnetic test coil of two in eddy current probe to detected object.
Described signal processing module can amplify the signal of eddy current probe feedback, the A/D conversion process of detection and filtering and necessity, wherein phase-sensitive detection circuit can lower the impact of leakage field on testing result of fault location effectively, and data export to control and display module by RS232 interface.
Described control and display module are respectively used to the detection feedback signal of display two groups of differential readout coils, can realize signal frequency, waveform phase angle, the isoparametric adjustment of signal gain, and can calculate testing result and store.
The present invention has higher accuracy in detection, sensitivity and stronger antijamming capability, and volume is little, easy to operate, and surface and the near surface flaw that can be applicable to boiler of power plant heating surface tube detect.
Accompanying drawing explanation
Fig. 1 is eddy detection system control principle block diagram of the present invention;
Fig. 2 is eddy detection system control flow chart of the present invention;
Fig. 3 is eddy current probe coil of the present invention distribution three-dimensional plot;
Fig. 4 is eddy current probe coil of the present invention distribution vertical view;
Fig. 5 is drive coil winding mode schematic diagram of the present invention;
Fig. 6 is differential readout coil-winding mode schematic diagram of the present invention;
Fig. 7 is rig-site utilization embodiment schematic diagram of the present invention;
Fig. 8 is phase-sensitive detection circuit schematic diagram;
Fig. 9 is workpiece and actual measurement impedance oscillogram figure.
Fig. 9 (a) is impedance oscillogram during workpiece existing defects;
Fig. 9 (b) is the surface chart catching the end points of curve in impedance oscillogram;
Fig. 9 (c) for workpiece not existing defects time impedance oscillogram.
Label declaration: 3-pops one's head in, 301-drive coil, 302-magnetic test coil, 302-1-first group of magnetic test coil, 302-2-second group of detection line.
Embodiment
Below with reference to the drawings and specific embodiments, the present invention is described in further details:
Embodiment 1:
See shown in Fig. 1 to Fig. 7, the present invention includes control and display module, signal processing module and eddy current probe 3, wherein signal processing module comprises signal generator, amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit composition, eddy current probe is the open eddy current probe of the shape of a saddle, the magnetic test coil 302 be connected with two groups of differential types by one group of drive coil 301 forms, two groups of magnetic test coils (302-1,302-2) are symmetric in drive coil 301 both sides, and sensing range covers whole probe arc surface.
All coils all comprise iron core, and iron core adopts the silicon steel plate packing that 0.2 ~ 0.5mm is thick, and siliconized plate front end is cambered surface, effectively can increase excitation field.Described signal generator can provide high-frequency oscillation signal for eddy current probe drive coil 301, frequency range can reach 10KHz ~ 500KHz, the high-frequency oscillation signal produced is transferred to the drive coil 301 in eddy current probe, by drive coil, magnetic field is loaded on detected object, then is gathered by the feedback signal of group magnetic test coil of two in eddy current probe 302 pairs of detected objects.
Then, the signal that signal processing module feeds back eddy current probe amplifies, detection and filtering process, and wherein phase-sensitive detection circuit 203 can lower the impact of leakage field on testing result of fault location effectively, exports to control and display module by RS232 interface.
Control and display module are made up of notebook computer and running background program, there is double screen binary channels display interface, be respectively used to the detection feedback signal of display two groups of differential readout coils 302, signal frequency, waveform phase angle, the isoparametric adjustment of signal gain can be realized, and can calculate testing result and store.
Fig. 7 is rig-site utilization embodiment schematic diagram of the present invention, elbow for pipe with small pipe diameter heating surface tubes in boilers carries out EDDY CURRENT, in figure, detection probe 3 is close to the interior elbow of heating surface tube, at the uniform velocity slides onto B position from A position, completes the EDDY CURRENT to elbow in heating surface tube; Be close to the outer elbow of heating surface tube, at the uniform velocity slide onto B ' position from A ' position, complete the EDDY CURRENT to the outer elbow of heating surface tube.
For Fig. 7, for disambiguation, make the following instructions: be a probe all the time during detection, elbow between A to B can be detected with probe, also outer elbow between A ' to B ' be can detect with probe, dirigibility when popping one's head in rig-site utilization and convenience embodied, simultaneously, what probe detected is also only defect on pipe one-sided pipe wall, is not the whole pipe defect of a week.
The impedance signal that probe coil detects, by amplifying circuit and phase-sensitive detection circuit, then after filtering and digital-to-analog conversion, be transferred to computer software platform, the approximate 8-shaped impedance oscillogram of display as shown in Fig. 9 (a), then by the backstage operation program that software is built-in, the end points catching curve carries out the calculating of phase place and amplitude, as Fig. 9 (b).
Illustrate: in the middle of Fig. 9 (a) and Fig. 9 (b), shorter little 8 words are not defective waveforms, for probe is when defect-free surface, due to out-of-flatness and other undesired signal noise signal after treatment of surface of the work, waveform during workpiece zero defect is as shown in Fig. 9 (c).
Claims (9)
1., based on a detection system for the open double-channel vortex probe of the shape of a saddle, it is characterized in that, comprise control module, signal processing module and probe;
Described probe is the open double-channel vortex probe of the shape of a saddle, and probe has a recessed arc surface, is provided with 1 drive coil and 4 magnetic test coils in probe; A 4 magnetic test coils between two component are 2 groups, and the both sides of the drive coil that is placed in; 1 drive coil and 4 magnetic test coils install around respectively on 5 iron-core coils;
Signal processing module comprises signal generator, amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit;
When detecting body to be detected, be placed on body to be detected by probe, the arc surface of probe presses close to the outer wall of body;
Signal generator is controlled by control module, and the output signal of signal generator is carried on drive coil;
The output signal of magnetic test coil enters control module successively after amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit process.
2. the detection system based on the open double-channel vortex probe of the shape of a saddle according to claim 1, it is characterized in that, two groups of magnetic test coils are symmetrically distributed in drive coil both sides, and 2 magnetic test coils often organized in magnetic test coil adopt differential type connected mode.
3. the detection system based on the open double-channel vortex probe of the shape of a saddle according to claim 1, it is characterized in that, it is the oscillator signal of 10KHz ~ 500KHz that signal generator produces frequency range.
4. the detection system based on the open double-channel vortex probe of the shape of a saddle according to claim 1, is characterized in that, also comprise the display module be connected with control module.
5. the detection system based on the open double-channel vortex probe of the shape of a saddle according to claim 4, it is characterized in that, display module is double screen, binary channels display module.
6. the detection system based on the open double-channel vortex probe of the shape of a saddle according to any one of claim 1-5, it is characterized in that, iron-core coil forms by the siliconized plate that multi-disc 0.2 ~ 0.5mm is thick is stacked.
7., based on a detection method for the open double-channel vortex probe of the shape of a saddle, it is characterized in that, adopt the detection system examinations described in any one of claim 1-5;
Be placed on body to be detected by probe, the arc surface of probe presses close to the outer wall of body;
By the drive coil of popping one's head in, magnetic field is loaded on body to be detected, gathered by the feedback signal of group magnetic test coil of two in eddy current probe to detected object and body to be detected, the signal of collection enters control module successively and processes after amplifying circuit, phase-sensitive detection circuit and current rectifying and wave filtering circuit process again.
8. the detection method based on the open double-channel vortex probe of the shape of a saddle according to claim 7, is characterized in that, during detection, moved by probe along body, collect feedback signal in moving process, realize the surface defect detection to straight tube or bend pipe.
9. the detection method based on the open double-channel vortex probe of the shape of a saddle according to claim 8, it is characterized in that, control module and signal processing module are by RS232 interface communication.
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Cited By (2)
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CN109791126A (en) * | 2016-10-06 | 2019-05-21 | 新东工业株式会社 | Surface characteristic inspection method and surface characteristic check device |
CN113311064A (en) * | 2021-05-25 | 2021-08-27 | 国网湖南省电力有限公司 | Pulse eddy current detection method and system for lead sealing part of cable joint |
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