CN102818838B - Electromagnetic torque change based method for nondestructive detection of defect in conductor - Google Patents
Electromagnetic torque change based method for nondestructive detection of defect in conductor Download PDFInfo
- Publication number
- CN102818838B CN102818838B CN201210291201.2A CN201210291201A CN102818838B CN 102818838 B CN102818838 B CN 102818838B CN 201210291201 A CN201210291201 A CN 201210291201A CN 102818838 B CN102818838 B CN 102818838B
- Authority
- CN
- China
- Prior art keywords
- permanent magnet
- conductor
- cylindrical permanent
- defect
- measured
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Abstract
The invention relates to an electromagnetic torque change based method for nondestructive detection of defects in a conductor, and belongs to the technical fields of power, electronic industry, metallurgical industry, semiconductor material and oil energy. This method is as below: first a torque sensor is set at one side of a cylindrical permanent magnet to drive the cylindrical permanent magnet to rotate, and conductors having no defects approach the rotating cylindrical permanent magnet, so as to measure a reference curve of change of rotating angular velocity of the cylindrical permanent magnet with time; and then a plurality of calibration curves of change of rotating angular velocity of permanent magnet with defects with time are measured; the permanent magnet approaches the conductor to be measured, so as to obtain a measurement curve; and the measurement curve is compared with the calibration curves, so as to obtain defect size of the conductor to be measured. The method is suitable for conductors such as wire, tubing and sheet metal; and the conductor to be measured does not need to move, thereby simplifying measurement conditions, measurement process, measurement cost and measurement equipment; besides, the method can easily realize automation and miniaturization, and can be applied to more fields and environment.
Description
Technical field
The present invention relates to a kind of lossless detection method based on defect in the conductor of electromagnetic torque change, particularly relate to the detection method of defect in a kind of thin plate class, wire rod, pipe fitting conductor, belong to electric power, electronics industry, metallurgical industry, semiconductor material, petroleum-based energy technical field.
Background technology
The metal materials such as pipe, wire rod and thin plate class may contain defect such as impurity (as oxide, sulfide grain etc.) hole, crackle etc. due to the reason of starting material and preparation technology, and this will have a strong impact on the usage performance of material.Such as in electric power, electronics industry, when then greatly reducing its electric property containing during non-conductive second-phase impurity particle in the materials such as plain conductor, sheet metal, circuit board, and reduce its physical strength, also may produce extra Joule heat during work, make device overheated, distortion even burn circuit and electronic equipment.In metallurgy and manufacturing industry industry, thin sheet material can be used for automobile, household electrical appliance, packaging for foodstuff, the housing of electronic product or encapsulating material, the thickness of the thin sheet material had is even less than 1 millimeter, if wherein will serious mass defect be become containing larger impurity, be therefore necessary very much to carry out Quantitative Monitoring in thin plate production run.In oil, chemical field, the pipeline of transfer oil or other chemical liquid owing to being on active service for a long time under the mal-conditions such as strong acid, highly basic or humidity (as submarine oil pipeline), as improper in material protection or extend service in the army as easy as rolling off a log generation galvanic corrosion or formed fatigue crack, because required maintenance condition is very inconvenient, then catastrophic effect may be caused if there is fault or material failure.Therefore effectively easy detection method is developed very necessary and there is national economy that is important, reality and science and techniques of defence meaning.Defect is referred to as convenience of describing the impurity, hole, crackle etc. that above-mentioned conductivity are approximately zero.
The main method of the Non-Destructive Testing utilizing electromagnetic principle to carry out at present has high-density electric (direct current), transient electromagnetic method, frequency domain electromagnetic methods, induced polarization method (applying frequency scope: 10
2-10
4hz) etc.High-density electric is a kind of contact method, there is electrode contact problem application scenario less.All the other methods above-mentioned are all utilize alternating electric field or electromagnetic detection method, need to provide Electromagnetic Sources, inspire secondary electrical field and magnetic field in testee, detect according to frequency domain character or electromagnetic field feature.In general, equipment is more complicated all, and the volume of measuring instrument is comparatively large, and the ability of suitable environment is very limited.
Summary of the invention
The object of the invention is to propose a kind of lossless detection method based on defect in the conductor of electromagnetic torque change, utilize the difference of conductivity between defect and conductor, quantitatively, non-direct contact detect the defect in conductor, and make test process simple and reliable.
What the present invention proposed comprises the following steps based on the lossless detection method of defect in the conductor of electromagnetic torque change:
(1) radially magnetize at one, thickness is that the side of the cylindrical permanent magnet of w arranges a torque sensor;
(2) drive cylindrical permanent magnet to rotate, remove driving force when cylindrical permanent magnet reaches an initial velocity, cylindrical permanent magnet is rotated further under inertia effect;
(3) make the cylindrical permanent magnet not containing the conductor of defect and rotation close, spacing distance is d, is recorded the time dependent reference curve of angular velocity of rotation of cylindrical permanent magnet by torque sensor;
(4) on conductor, drilled diameter does not wait and spacing distance is greater than multiple apertures of cylindrical magnet body thickness w, by the rotational circle cylindricality permanent magnet of step (2) aperture that multiple diameter does not wait on conductor successively, obtain the time dependent multiple calibration curve of angular velocity of rotation of cylindrical permanent magnet;
(5) by the rotational circle cylindricality permanent magnet of step (2) near measured conductor, obtain the time dependent experiment curv of angular velocity of rotation of a cylindrical permanent magnet;
(6) calibration curve of the experiment curv of step (5) and step (4) is compared, if experiment curv and a calibration curve coincide, then the flaw size of measured conductor equals the orifice size corresponding with this calibration curve, if experiment curv is between adjacent two calibration curves, then the flaw size of measured conductor is between two orifice sizes that calibration curve corresponding adjacent with this.
The lossless detection method based on defect in the conductor of electromagnetic torque change that the present invention proposes, has following characteristics and advantage:
1, the inventive method is applicable to the conductor of wire rod, tubing and thin plate class, and measured conductor need not move, and simplifies measuring condition, measuring process and measurement cost, therefore can simplified measurement equipment greatly;
2, the inventive method is in measuring process, and measured conductor does not directly contact with surveying instrument, is a kind of lossless detection method, and only need measure angular velocity of rotation change, and need not measure corresponding power, therefore measuring process is convenient and simple;
3, the inventive method is compared with the existing lossless detection method utilizing electromagnetic principle to carry out, and the inventive method is simple, according to the detection instrument of the inventive method design, easily is automated and miniaturization, can be applied in more field and environment.
Accompanying drawing explanation
Fig. 1 is the schematic diagram using the inventive method to carry out the embodiment measured.
Fig. 2 uses the inventive method calibration process schematic diagram, and wherein reference curve is not containing angular velocity time dependent curve during impurity, curve 1,2 ..., the demarcation aperture that n is corresponding is of a size of d
1, d
2..., d
n, the magnitude relationship of aperture is d
1< d
2< ... < d
n.
Fig. 3 is the measuring principle schematic diagram using the inventive method.
In Fig. 1 ~ Fig. 3,1 is cylindrical permanent magnet, and 2 is the thin axles of stainless steel being with taper, and 3 is glass ceramics bracing frames, and 4 is copper posts, and 5 is coupling shafts, and 6 is motors, and 7 is measured conductors, and 8 is the defects in conductor, and 9 is faradic sensitizing ranges.
Embodiment
The lossless detection method based on defect in the conductor of electromagnetic torque change that the present invention proposes, the principle schematic of embodiment as shown in Figure 1, comprises the following steps:
(1) radially magnetize at one, thickness is that the side of w cylindrical permanent magnet 1 arranges a torque sensor (not shown);
(2) drive cylindrical permanent magnet 1 to rotate, remove driving force when cylindrical permanent magnet 1 reaches an initial velocity, cylindrical permanent magnet 1 is rotated further under inertia effect; In one embodiment of the invention, adopt the method for electromagnetic induction to drive cylindrical permanent magnet 1 to rotate, as shown in Figure 1, achieve driving to cylindrical permanent magnet 1 by the copper post 4 that rotates under driving at motor 6 based on the method for electromagnetic induction;
(3) make cylindrical magnet 1 body not containing the conductor of defect and rotation close, spacing distance is d, is recorded the time dependent reference curve of angular velocity of rotation of cylindrical permanent magnet, as shown in Figure 2 by torque sensor;
(4) in order to quantitative measurment flaw size, following calibration experiment is made in advance: drilled diameter does not wait and spacing distance is greater than multiple apertures of cylindrical magnet body thickness w, to simulate the defect of not equidimension on conductor.Respectively by the rotational circle cylindricality permanent magnet 1 of step (2) aperture that multiple diameter does not wait on conductor successively, obtain the time dependent multiple calibration curve of angular velocity of rotation of cylindrical permanent magnet; Because aperture is larger, the electromagnetic force responded to is less, and the moment of torsion suffered by magnet is less.Angular velocity of rotation is decayed slack-off in time.Such as hole diameter is d
1< d
2< ... < d
n, then measured curve will be respectively 1,2 ..., n;
(5) by the rotational circle cylindricality permanent magnet 1 of step (2) near measured conductor 7, obtain the time dependent experiment curv of angular velocity of rotation of a cylindrical permanent magnet;
(6) calibration curve of the experiment curv of step (5) and step (4) is compared, if experiment curv and a calibration curve coincide, then the flaw size of measured conductor equals the orifice size corresponding with this calibration curve, if experiment curv is between adjacent two calibration curves, then the flaw size of measured conductor is between two orifice sizes that calibration curve corresponding adjacent with this.
Ultimate principle of the present invention is as follows:
As shown in Fig. 3 (a), column shaped rotating permanent magnet 1 forms rotating magnetic field around it, the conductor 7 surveyed is in the rotating magnetic field internal cutting magnetic line of force will produce induction current therein, and induction current and magnetic field interaction produce Lorentz force in conductor.According to the conductor 7 that Newton third law (action-reaction law) is surveyed, opposite effect power in equal and opposite in direction direction is produced to the cylindrical permanent magnet 1 rotated, the electromagnetic torque produced hinders the rotary motion of cylindrical permanent magnet 1, cylindrical permanent magnet 1 rotational speed is decayed until stop, i.e. electromagnetic braking process.As shown in Fig. 3 (b), the induction current produced in said process when above-mentioned conductor 7 includes defectiveness 8 (defect is non-conductive) reduces, and then the electromagnetic force produced also reduces, corresponding electromagnetic torque also reduces, on the time dependent curve of angular velocity of rotation that this reduction process can be reflected to cylindrical permanent magnet 1, this curve negotiating electromagnetic sensor can be measured.Like this, size and the distributed intelligence of defect 8 in electric conductor 7 can be released by this curvilinear motion.
The present invention is applicable to the detection of non-conductive impurity or defect in pipe, line, thin plate class electric conductor, and because the thickness of above-mentioned material is less, detected conductor object can be easy to meet electromagetic field osmosis condition: detect thickness is less than to become skin layers thickness; In addition, between the aperture that demarcation adopts and defect, the impact of difference also can be very little, can ignore.
According to the ultimate principle of the invention described above, the invention will be further described:
Distance d when ensureing use safety between cylindrical permanent magnet 1 and measured conductor 7 is the smaller the better, to obtaining stronger magnetic field in measured conductor 7, and then obtains stronger measuring-signal.
As shown in Fig. 3 (a), the induction current that the cylindrical permanent magnet 1 of rotation produces in measured conductor 7 has an integrated distribution region, claims this region to be faradic sensitizing range 9.Its dimension information could be obtained when defect 8 is positioned at faradic sensitizing range 9.As shown in Fig. 3 (b), faradic sensitizing range 9 should adapt with flaw size: faradic sensitizing range 9 should be too large, otherwise the measured angular velocity containing defect 8 over time curve and reference curve difference not obvious; Faradic sensitizing range 9 should be too not little yet, otherwise when measuring, defect 8, beyond the scope of faradic sensitizing range 9, is measured and will be can not get defect dimension information accurately.
Above-mentioned faradic sensitizing range 9 is roughly the same with the thickness of cylindrical permanent magnet 1, and therefore the thickness of cylindrical permanent magnet 1 determines the minimum and maximum resolution being detected defect 8.The thickness of cylindrical permanent magnet 1 generally elects the nominal size slightly larger than detecting defect as; Faradic sensitizing range 9 is also relevant with the diameter of cylindrical permanent magnet 1.
Obtain an initial angular velocity for making cylindrical permanent magnet 1 and can have distinct methods, as can Mechanical Driven be adopted, then survey except driving force carries out above-mentioned measuring process again.Have employed the method that electromagnetic induction drives in the embodiment in figure 1.Be provided with the cylindrical, copper post 4 that an axis is in parallel in the side of cylindrical permanent magnet 1, cylindrical, copper post 4 is connected with motor 6 by coupling shaft 5.Concrete measurement procedure is as follows: driven by motor 6 and copper post 4 is rotated, the copper post 4 being in the rotation in the magnetic field of cylindrical permanent magnet 1 generation obtains induction current, cylindrical, copper post 4 is subject to induction current and magnetic fields produces Lorentz force, and its reacting force drives cylindrical permanent magnet 1 to rotate.After cylindrical permanent magnet 1 reaches certain rotating speed and be steady, the motor 6 of withdrawing copper post 4 fast and being attached thereto, makes cylindrical permanent magnet 1 obtain certain initial angular velocity, and keeps rotating under inertia effect.
In the embodiment in figure 1, in order to reduce the friction force between cylindrical permanent magnet 1 and bracing frame 3 as far as possible, bracing frame 1 have employed glass ceramic material, and thin axle 2 adopts the stainless steel rod structure of double headed roller taper.Bracing frame 3 processes concave shaped duck eye with fixing thin axle 2, above-mentioned measure can eliminate the impact of friction force on measuring process substantially.
Claims (1)
1., based on a lossless detection method for defect in the conductor of electromagnetic torque change, it is characterized in that this lossless detection method comprises the following steps:
(1) radially magnetize at one, thickness is that the side of the cylindrical permanent magnet of w arranges a torque sensor;
(2) drive cylindrical permanent magnet to rotate, remove driving force when cylindrical permanent magnet reaches an initial velocity, cylindrical permanent magnet is rotated further under inertia effect;
(3) make the cylindrical permanent magnet not containing the conductor of defect and rotation close, spacing distance is d, and recorded the time dependent reference curve of angular velocity of rotation of cylindrical permanent magnet by torque sensor, described defect is non-conductive;
(4) on conductor, drilled diameter does not wait and spacing distance is greater than multiple apertures of cylindrical magnet body thickness w, by the rotational circle cylindricality permanent magnet of step (2) aperture that multiple diameter does not wait on conductor successively, obtain the time dependent multiple calibration curve of angular velocity of rotation of cylindrical permanent magnet;
(5) by the rotational circle cylindricality permanent magnet of step (2) near measured conductor, obtain the time dependent experiment curv of angular velocity of rotation of a cylindrical permanent magnet;
(6) calibration curve of the experiment curv of step (5) and step (4) is compared, if experiment curv and a calibration curve coincide, then the flaw size of measured conductor equals the orifice size corresponding with this calibration curve, if experiment curv is between adjacent two calibration curves, then the flaw size of measured conductor is between two orifice sizes that calibration curve corresponding adjacent with this.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210291201.2A CN102818838B (en) | 2012-08-15 | 2012-08-15 | Electromagnetic torque change based method for nondestructive detection of defect in conductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210291201.2A CN102818838B (en) | 2012-08-15 | 2012-08-15 | Electromagnetic torque change based method for nondestructive detection of defect in conductor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102818838A CN102818838A (en) | 2012-12-12 |
| CN102818838B true CN102818838B (en) | 2015-03-04 |
Family
ID=47303082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210291201.2A Active CN102818838B (en) | 2012-08-15 | 2012-08-15 | Electromagnetic torque change based method for nondestructive detection of defect in conductor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102818838B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202196038U (en) * | 2011-08-12 | 2012-04-18 | 西安思坦仪器股份有限公司 | High-resolution electromagnetic flaw detector and control system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1061698A (en) * | 1996-08-16 | 1998-03-06 | Tokyo Buhin Kogyo Kk | Braking torque detecting device of drum brake |
| GB9907130D0 (en) * | 1999-03-26 | 1999-05-19 | Fet Applic Limited | Torque and speed sensor |
-
2012
- 2012-08-15 CN CN201210291201.2A patent/CN102818838B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202196038U (en) * | 2011-08-12 | 2012-04-18 | 西安思坦仪器股份有限公司 | High-resolution electromagnetic flaw detector and control system |
Non-Patent Citations (2)
| Title |
|---|
| 《新型磁传感器理论及其在钢板缺陷检测的应用》;闻凤连等;《仪表技术与传感器》;20100228(第2期);第70-72页 * |
| 《焊缝小角度裂纹缺陷的磁轭法检测》;宋庆红;《无损检测》;20080630;第30卷(第6期);第47-51页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102818838A (en) | 2012-12-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7631564B1 (en) | Direct shaft power measurements for rotating machinery | |
| EP2213995A2 (en) | Magnetostrictive sensing systems and methods for encoding | |
| CN103645243A (en) | Electromagnetic nondestructive detection system of power transmission line | |
| Lee et al. | Magnetostrictive patch sensor system for battery-less real-time measurement of torsional vibrations of rotating shafts | |
| CN103499404A (en) | Measuring device and measuring method for alternating stress of ferromagnetic component | |
| CN104880508A (en) | Orthogonal rotation exciting field eddy current transducer | |
| CN104048595A (en) | Angle misalignment fault quantitative detection system and method for rotating machine | |
| CN103575803A (en) | Lorentz force eddy current testing method and device for detecting defects of nonferromagnetic metal material | |
| CN102809727A (en) | Motor rotor turn-to-turn short circuit fault detection method based on frequency response analysis | |
| CN101430188B (en) | On-line monitoring device and method for rotating shaft position of magnetic pump | |
| Borges et al. | New contactless torque sensor based on the Hall effect | |
| CN104006909A (en) | Cable force detecting method and cable force sensor using same | |
| CN108387331A (en) | A kind of test method of the real-time dynamic stress of disc type pull rod composite class rotor | |
| CN103335735A (en) | Temperature detection device for rotary part | |
| RU2585482C1 (en) | Device for measurement of torque, shaft speed and power on shaft | |
| CN102818838B (en) | Electromagnetic torque change based method for nondestructive detection of defect in conductor | |
| KR101346309B1 (en) | Ultrasonic inspection device for purforming non-destructive test | |
| CN108375437A (en) | Ship shaft power measurement method based on counter magnetostriction effect | |
| CN101813655B (en) | Device and method for measuring carbon fiber reinforced plastic based on electromagnetic sensing | |
| CN201177650Y (en) | Cage type induction motor having detection coil and detection apparatus for broken strip of rotor | |
| CN109060210B (en) | Bearing friction torque measuring method and system based on piezoelectric ceramics | |
| CN203856903U (en) | Temperature self-monitoring ball bearing | |
| CN203730531U (en) | Transmission shaft provided with device capable of performing on-line monitoring on torque in real time | |
| CN202975039U (en) | Device for measuring rotating speed of rotating member through electrostatic sensor | |
| CN104330635A (en) | Method for detecting conductivity of object based on measurement of electromagnetic torque change |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |