CN101556253B - Device and method for detecting hidden metal articles - Google Patents
Device and method for detecting hidden metal articles Download PDFInfo
- Publication number
- CN101556253B CN101556253B CN2008100357634A CN200810035763A CN101556253B CN 101556253 B CN101556253 B CN 101556253B CN 2008100357634 A CN2008100357634 A CN 2008100357634A CN 200810035763 A CN200810035763 A CN 200810035763A CN 101556253 B CN101556253 B CN 101556253B
- Authority
- CN
- China
- Prior art keywords
- signal
- metal
- circuit
- hidden
- amount
- 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.)
- Expired - Fee Related
Links
Images
Abstract
The invention discloses a device and a method for detecting hidden metal articles, which can detect the material quality and the amount of hidden metal conveniently and rapidly and judges whether the hidden metal carries hazard materials. The invention judges whether hazard materials exist or not by detecting the material quality and the amount of the hidden metal and detects the static metal signal which can influence the environment so as to obviously increase the accuracy and convenience of the detection compared with the prior art. The invention is applied to the field of hazard material detection.
Description
Technical field
The present invention relates to a kind of safety detecting device and method, relate in particular to a kind of sniffer and method of distinguishing the hiding dangerous goods of metal material and amount of metal size.
Background technology
, mainly be that through type detector gate and hand-held metal detector carry out general physical checkup to the people at present in the safety inspection to the people in important places such as airport, being combined in a lot of occasions and can meeting the demands of this dual mode, but wherein leak is exactly here: shoes.Detector gate can't be checked areas of footwear owing to surveying reason, and itself just there is metal shoes inside, checks that with the hand-held metal detector false-alarm is too many.Therefore in the higher occasion of level of security, often need the inspection of taking off one's shoes, this test mode wastes time and energy, and has increased staff's workload greatly, has increased tested personnel's resentment simultaneously.
Summary of the invention
The objective of the invention is to address the above problem, a kind of sniffer of hidden metal articles is provided, can conveniently measure metal material and the amount of metal of hiding metal, and judge whether to carry the possibility of dangerous goods in view of the above.
Another object of the present invention is to provide a kind of detection method of hidden metal articles, can conveniently measure metal material and the amount of metal of hiding metal, and judged whether to carry the possibility of dangerous goods in view of the above.
Technical scheme of the present invention is: the present invention has disclosed a kind of sniffer of hidden metal articles, comprising:
The metal induction pick-up comprises:
The emission driving circuit that has transmitting coil, the electromagnetic field of generation alternation on this transmitting coil;
The receiving circuit that has receiving coil, wherein this receiving circuit induces corresponding electromotive force y1=A1cos (wt) on a receiving coil therein, on another receiving coil, induce corresponding electromotive force y2=A2cos (wt), signal y1 becomes y1 '=A1K1cos (wt+q0) when keeping metal, wherein A1, A2 represent signal magnitude, w representation signal frequency, K1 represents the information of amount of metal, and q0 represents the information of metal material;
Signal analyse block comprises:
Phase-shift circuit is connected the output terminal of this receiving circuit, signal y2 is become: y3=A3cos (wt+q1) after phase shift is handled, A3 represent signal magnitude wherein, proportional with A2, q1 is the phase differential of the relative y1 of signal y3, is known in this phase-shift circuit;
Detecting circuit, received signal y1 ' and signal y3, both are multiplied each other obtains signal y4, wherein y4=y1 ' * y3=0.5A1K1A3[cos (q0-q1)+cos (2wt+q0+q1)];
Signal filter circuit, received signal y4 is through output low frequency component y5, wherein y5=0.5A1K1A3cos (q0-q1) after the low-pass filtering;
Subtracter, received signal y5 and static metal signal are exported both poor, should the static state metal signal be the environment low frequency component values that influence is produced to device wherein;
Analog to digital converter receives the output of subtracter, converts thereof into digital signal;
Microcontroller connects this analog to digital converter, and microcontroller is judged the metal material and the amount of metal of correspondence from the output of analog to digital converter, and this amount of metal and default amount of metal are compared, and makes a judgement signal if difference exceeds a setting value;
Sequential control circuit connects this emission driving circuit, this receiving circuit and this detecting circuit, control three's synchronization action.
Above-mentioned hidden metal articles sniffer, wherein, this device also comprises:
Human-computer interaction module comprises:
Man Machine Interface;
Embedded computer is controlled with caution user or reception user's input according to the judgement signal operation Man Machine Interface of this microcontroller output.
Above-mentioned hidden metal articles sniffer, wherein, this Man Machine Interface comprises liquid crystal indicator and loudspeaker.
Above-mentioned hidden metal articles sniffer wherein, adds that on magnetic circuit that installs and circuit magnetic masking layer is to isolate, to reduce the influence of the metal pair coil in the environment.
Above-mentioned hidden metal articles sniffer, wherein, this sniffer also comprises:
Infrared sensor has judged whether detected target.
The present invention has disclosed a kind of detection method of hidden metal articles in addition, comprising:
(1) produces the electromagnetic field of alternation by transmitting coil;
(2) induce corresponding electromotive force by receiving coil, the electromotive force that induces on receiving coil is y1=A1cos (wt) therein, the electromotive force that induces on another receiving coil is y2=A2cos (wt), signal y1 becomes y1 '=A1K1cos (wt+q0) when keeping metal on the human body, wherein A1, A2 represent signal magnitude, w representation signal frequency, K1 represents the information of amount of metal, and q0 represents the information of metal material;
(3) will become y3=A3cos (wt+q1) after the signal y2 phase shift processing, wherein the A3 represent signal magnitude is proportional with A2, and q1 is the phase differential of the relative y1 of signal y3, is known in phase shift is handled;
(4) signal y1 ' and signal y3 are carried out detection and handle, be about to obtain signal y4 after both multiply each other, wherein y4=y1 ' * y3=0.5A1K1A3[cos (q0-q1)+cos (2wt+q0+q1)];
(5) signal y4 is carried out obtaining low frequency component y5 after the low-pass filtering, wherein y5=0.5A1K1A3cos (q0-q1);
(6) deduct static metal signal from low frequency component y5, wherein static metal signal is the low frequency component value that the environment metal produces;
(7) the difference analog to digital conversion in the previous step is become digital signal;
(8) from digital signal, judge pairing metal material of hiding metal and amount of metal, this amount of metal and the amount of metal of presetting are compared, if difference exceeds preset value and then exports alarm signal.
The detection method of above-mentioned hidden metal articles, wherein, this detection method also comprises the process of man-machine interaction.
The detection method of above-mentioned hidden metal articles, wherein, this alarm signal comprises picture signal or sound signal.
The detection method of above-mentioned hidden metal articles, wherein, this detection method also comprises:
Reduce the influence of the metal pair result of detection in the environment in the magnetic shielding mode.
The detection method of above-mentioned hidden metal articles, wherein, this detection method also comprises:
Judged whether detected target by infrared sensor.
The present invention contrasts prior art following beneficial effect: the present invention is by judging whether to have danger to the metal material of hiding metal and the detection of amount of metal, and be aided with detection to the static metal signal of environmental impact, so that the accuracy and the convenience that detect increase significantly compared to prior art.
Description of drawings
Fig. 1 is the schematic diagram of preferred embodiment of the sniffer of hidden metal articles of the present invention.
Fig. 2 is the process flow diagram of preferred embodiment of the detection method of hidden metal articles of the present invention.
Embodiment
The invention will be further described below in conjunction with drawings and Examples.
Whether Fig. 1 carries hiding metal threat object product with human body foot is example, shows the principle of the sniffer of hidden metal articles of the present invention.See also Fig. 1, device comprises emission driving circuit 100, left foot receiving circuit 101a, right crus of diaphragm receiving circuit 101b, phase-shift circuit 102, detecting circuit 103, signal filter circuit 104, subtracter 105, analog to digital converter (ADC) 106, microcontroller (MCU) 107, embedded computer 108, Man Machine Interface 109, sequential control circuit 110.Device can also comprise infrared sensor, is used to judge whether that the detection of a target enters detecting area.
If there is metal to exist in alternating magnetic field, because the physical property difference of different metal, the effect that produces in alternating magnetic field is also different, at characterization parameter commonly used in such cases magnetic permeability μ and conductivity δ is arranged.Various metals are owing to its material property difference of forming, and magnetic permeability μ and conductivity δ also have nothing in common with each other.Be in the metal in the alternating magnetic field because eddy effect (δ is relevant with conductivity) or magnetic effect (μ is relevant with magnetic permeability) will produce a complementary field, the magnetic line of force that destroys primary field distributes, and this complementary field is called secondary field again.The secondary field that metal produced can destroy the mobile equilibrium of alternating magnetic field in the receiving coil, thereby produces corresponding induction electromotive force in receiving coil.In the present embodiment, the induction electromotive force on the receiving coil of left foot receiving circuit 101a becomes: y1 '=A1K1cos (wt+q0), and wherein K1 represents the information of amount of metal, and q0 represents the information of metal material.
Phase-shift circuit 102 is right after after right crus of diaphragm receiving circuit 101b, signal y2 is carried out phase shift handle the signal after the processing: y3=A3cos (wt+q1), A3 represent signal magnitude wherein, A3 and A2 are proportional, and q1 is the phase differential of the relative y1 of signal y3, and q1 is known in phase-shift circuit 102.
Detecting circuit 103 is right after after left foot receiving circuit 101a and phase-shift circuit 102, signal y1 ' and y3 are carried out the detection processing, exactly two signal multiplications are obtained signal y4, wherein y4=y1 ' * y3=0.5A1K1A3[cos (q0-q1)+cos (2wt+q0+q1)].
Sequential control circuit 110 connects emission driving circuit 100, left foot receiving circuit 101a, right crus of diaphragm receiving circuit 101b and detecting circuit 103, controls the synchronous operation of these circuit.
One of subtracter 105 input termination signal filter circuit 104, the static metal signal of another input termination, output terminal obtains is both poor of signal y5 and static metal signal.Static metal signal is the environment low frequency component that influence is produced to device.
Analog to digital converter (ADC) 106 converts the output of the analog quantity form of subtracter 105 to digital signal, microcontroller (MCU) 107 is judged corresponding metal material and amount of metal from this digital signal, and the amount of metal judged and default amount of metal made comparisons, then export one and judge signal if difference exceeds preset value.
Above-mentioned phase-shift circuit 102, detecting circuit 103, signal filter circuit 104, subtracter 105, analog to digital converter (ADC) 106, microcontroller (MCU) 107 and sequential control circuit 110 have constituted signal analyse block together.
Behind microcontroller (MCU) 107, also be connected to embedded computer 108 and Man Machine Interface 109, the human-computer interaction module of both constituent apparatus.Embedded computer 108 is according to the judgement signal operation Man Machine Interface 109 (for example being liquid crystal indicator, loudspeaker etc.) of microcontroller (MCU) 107 outputs, with the caution user.Certainly, Man Machine Interface 109 input that also can receive the user is carried out certain operation with control embedded computer 108.The control enclosure of signal analyse block and human-computer interaction module component devices.The mode that probe station and controller combine, both the convenient installation requirement under multiple environment also can make things convenient for safety check staff operation.
In order to make testing result more accurate, device must manage to shield the influence of environment to testing result.Environment mainly contains ground metal and the influence of large-scale instrument metal on every side to the influence of device testing result.The modern architecture overwhelming majority is a reinforced concrete structure, and the reinforcing bar in the floor reacts to the detection of device equally.Simultaneously because the character of use occasion, around this device, must also have other large-scale metallic object, such as X-ray machine etc.In order to guarantee the correctness of testing result, must eliminate the influence of this part environment metal pair device.
At first from the principle of metal detection, the change of detecting coil signal is that this secondary magnetic field has influenced again and transmitted because the magnetic field that its emission causes has produced secondary magnetic field on measured object.The magnetic field conversion that completely cuts off floor bar will add magnetic masking layer between coil and floor.The material of the magnetic masking layer that adopts must have higher magnetic permeability and lower coercive force, and very high resistivity is arranged again simultaneously.On magnetic circuit that installs and circuit, add magnetic masking layer, can make the influence of the metal pair detecting coil in the floor drop to minimum to isolate.
The equipment such as device meeting and X-ray machine of considering use together, and this kind equipment also can produce certain influence to the Device Testing result, and this class influence is complicated more and be full of unpredictable.This device adopts correction module to get rid of this influence, can carry out once study earlier to environment, be exactly under the situation of device vacant (promptly not putting into any object), to obtain low frequency component specifically from signal filter circuit 104, the low frequency component that obtains by this way is exactly above-mentioned static metal signal, can in actual detected as the input of subtracter 105.
Based on above-mentioned device, the present invention also provides the detection method to hidden metal articles, and the flow process of method sees also Fig. 2, is the detailed description to each step in this method below.
Step S200: judged whether that earlier the detection of a target enters detecting area, then entered step S200, otherwise flow process finishes if having.Be to have judged whether that by infrared sensor the detection of a target enters detector in the present embodiment.
Step S201: the electromagnetic field that produces alternation by transmitting coil.
Step S202: induce corresponding electromotive force by receiving coil, the electromotive force that induces on receiving coil is y1=A1cos (wt) therein, and the electromotive force that induces on another receiving coil is y2=A2cos (wt).Wherein A1, A2 represent signal magnitude.
Step S203: the electromotive force y1 that receiving coil induces becomes y1 '=A1K1cos (wt+q0), and wherein K1 represents the information of amount of metal, and q0 represents the information of metal material.
Step S204: signal y2 is done phase shift handle, become y3=A3cos (wt+q1), A3 represent signal magnitude and proportional wherein with A2, q1 is the phase differential of the relative y1 of signal y3 and is known quantity in phase shift is handled.
Step S205: signal y1 ' and signal y3 are carried out detection handle, also be about to obtain signal y4 after both multiply each other, wherein y4=y1 ' * y3=0.5A1K1A3[cos (q0-q1)+cos (2wt+q0+q1)].
Step S206: signal y4 is carried out obtaining low frequency component y5 after the low-pass filtering, wherein y5=0.5A1K1A3cos (q0-q1).
Step S207: deduct static metal signal from low frequency component y5, wherein static metal signal is the low frequency component value that the environment metal produces.
Step S208: difference is carried out analog to digital conversion, obtain digital signal.
Step S209: from digital signal, judge pairing metal material of hiding metal and amount of metal.
Step S210: whether the difference of judging amount of metal and default amount of metal exceeds preset value.If exceed preset value then enter step S211, otherwise flow process finishes.
Step S211: output alarm signal.For example by display device output image alarm signal, by audio output device output audio alarm signal etc.
Step S212: judge whether target is left, if left then returned step S200, otherwise repeating step S212.
Above-mentioned detection method man-machine interaction process, the input that for example receives the user is to carry out certain operation.In order to make testing result more accurate, detection method also comprises the influence that reduces environment metal pair result of detection in the magnetic shielding mode.
The foregoing description provides to those of ordinary skills and realizes or use of the present invention; those of ordinary skills can be under the situation that does not break away from invention thought of the present invention; the foregoing description is made various modifications or variation; thereby protection scope of the present invention do not limit by the foregoing description, and should be the maximum magnitude that meets the inventive features that claims mention.
Claims (10)
1. the sniffer of a hidden metal articles comprises:
The metal induction pick-up comprises:
The emission driving circuit that has transmitting coil, the electromagnetic field of generation alternation on this transmitting coil;
The receiving circuit that has receiving coil, wherein this receiving circuit induces corresponding electromotive force y1=A1cos (wt) on a receiving coil therein, on another receiving coil, induce corresponding electromotive force y2=A2cos (wt), signal y1 becomes y1 '=A1K1cos (wt+q0) when keeping metal, wherein A1, A2 represent signal magnitude, w representation signal frequency, K1 represents the information of amount of metal, and q0 represents the information of metal material;
Signal analyse block comprises:
Phase-shift circuit is connected the output terminal of this receiving circuit, signal y2 is become: y3=A3cos (wt+q1) after phase shift is handled, A3 represent signal magnitude wherein, proportional with A2, q1 is the phase differential of the relative y1 of signal y3, is known in this phase-shift circuit;
Detecting circuit, received signal y1 ' and signal y3, both are multiplied each other obtains signal y4, wherein y4=y1 ' * y3=0.5A1K1A3[cos (q0-q1)+cos (2wt+q0+q1)];
Signal filter circuit, received signal y4 is through output low frequency component y5, wherein y5=0.5A1K1A3cos (q0-q1) after the low-pass filtering;
Subtracter, received signal y5 and static metal signal are exported both poor, should the static state metal signal be the environment low frequency component values that influence is produced to device wherein;
Analog to digital converter receives the output of subtracter, converts thereof into digital signal;
Microcontroller connects this analog to digital converter, and microcontroller is judged the metal material and the amount of metal of correspondence from the output of analog to digital converter, and this amount of metal and default amount of metal are compared, and makes a judgement signal if difference exceeds a setting value;
Sequential control circuit connects this emission driving circuit, this receiving circuit and this detecting circuit, control three's synchronization action.
2. hidden metal articles sniffer according to claim 1 is characterized in that, this device also comprises:
Human-computer interaction module comprises:
Man Machine Interface;
Embedded computer is controlled with caution user or reception user's input according to the judgement signal operation Man Machine Interface of this microcontroller output.
3. hidden metal articles sniffer according to claim 2 is characterized in that this Man Machine Interface comprises liquid crystal indicator and loudspeaker.
4. hidden metal articles sniffer according to claim 1 is characterized in that, adds that on the magnetic circuit of this device and circuit magnetic masking layer is to isolate, to reduce the influence of the metal pair coil in the environment.
5. hidden metal articles sniffer according to claim 1 is characterized in that, this sniffer also comprises:
Infrared sensor has judged whether detected target.
6. the detection method of a hidden metal articles comprises:
(1) produces the electromagnetic field of alternation by transmitting coil;
(2) induce corresponding electromotive force by receiving coil, the electromotive force that induces on receiving coil is y1=A1cos (wt) therein, the electromotive force that induces on another receiving coil is y2=A2cos (wt), signal y1 becomes y1 '=A1K1cos (wt+q0) when keeping metal on the human body, wherein A1, A2 represent signal magnitude, w representation signal frequency, K1 represents the information of amount of metal, and q0 represents the information of metal material;
(3) will become y3=A3cos (wt+q1) after the signal y2 phase shift processing, wherein the A3 represent signal magnitude is proportional with A2, and q1 is the phase differential of the relative y1 of signal y3, is known in phase shift is handled;
(4) signal y1 ' and signal y3 are carried out detection and handle, be about to obtain signal y4 after both multiply each other, wherein y4=y1 ' * y3=0.5A1K1A3[cos (q0-q1)+cos (2wt+q0+q1)];
(5) signal y4 is carried out obtaining low frequency component y5 after the low-pass filtering, wherein y5=0.5A1K1A3cos (q0-q1);
(6) deduct static metal signal from low frequency component y5, wherein static metal signal is the low frequency component value that the environment metal produces;
(7) the difference analog to digital conversion in the previous step is become digital signal;
(8) from digital signal, judge pairing metal material of hiding metal and amount of metal, this amount of metal and the amount of metal of presetting are compared, if difference exceeds preset value and then exports alarm signal.
7. the detection method of hidden metal articles according to claim 6 is characterized in that, this detection method also comprises the process of man-machine interaction.
8. the detection method of hidden metal articles according to claim 6 is characterized in that, this alarm signal comprises picture signal or sound signal.
9. the detection method of hidden metal articles according to claim 6 is characterized in that, this detection method also comprises:
Reduce the influence of the metal pair result of detection in the environment in the magnetic shielding mode.
10. the detection method of hidden metal articles according to claim 6 is characterized in that, this detection method also comprises:
Judged whether detected target by infrared sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008100357634A CN101556253B (en) | 2008-04-09 | 2008-04-09 | Device and method for detecting hidden metal articles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008100357634A CN101556253B (en) | 2008-04-09 | 2008-04-09 | Device and method for detecting hidden metal articles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101556253A CN101556253A (en) | 2009-10-14 |
| CN101556253B true CN101556253B (en) | 2011-09-21 |
Family
ID=41174449
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008100357634A Expired - Fee Related CN101556253B (en) | 2008-04-09 | 2008-04-09 | Device and method for detecting hidden metal articles |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101556253B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102010031147A1 (en) * | 2010-05-07 | 2011-11-10 | Robert Bosch Gmbh | Detecting a metallic or magnetic object |
| CN103115634B (en) * | 2013-03-05 | 2015-07-08 | 上海兰宝传感科技股份有限公司 | Multi-coil material distinguishing inductive transducer |
| CN103175551B (en) * | 2013-03-05 | 2015-06-24 | 上海兰宝传感科技股份有限公司 | Inductive sensor with attenuation coefficient which is one |
| CN105005083A (en) * | 2015-07-24 | 2015-10-28 | 广州彩磁信息技术有限公司 | Safety inspection system based on conjugate electromagnetic transmit-receive array broadband detection and visual display and method thereof |
| CN105866845A (en) * | 2016-03-25 | 2016-08-17 | 东莞市华盾电子科技有限公司 | Hand-held electronic device detector |
| CN105866176B (en) * | 2016-03-25 | 2019-02-05 | 东莞市华盾电子科技有限公司 | Scaling method, test method and its system of sorting metals detection |
| CN105866846A (en) * | 2016-03-25 | 2016-08-17 | 东莞市华盾电子科技有限公司 | Hand-held iron weapon detector |
| CN106018449A (en) * | 2016-07-18 | 2016-10-12 | 北京紫方启研科技有限公司 | Sole backscattering imager |
| CN110308491B (en) * | 2019-05-29 | 2021-11-05 | 浙江大华技术股份有限公司 | Article detection method, article detection device, storage medium, and electronic device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0978734A3 (en) * | 1998-08-05 | 2001-07-11 | MAIER, Hans-Jürgen | Apparatus for detection of metallic objects |
| CN2859520Y (en) * | 2005-12-29 | 2007-01-17 | 中国电子科技集团公司第五十研究所 | Shoe-inside safety detecting instrument capable of distinguishing copper, iron and aluminium |
| CN1975396A (en) * | 2006-12-28 | 2007-06-06 | 张恩伟 | In-shoe safety detector |
-
2008
- 2008-04-09 CN CN2008100357634A patent/CN101556253B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0978734A3 (en) * | 1998-08-05 | 2001-07-11 | MAIER, Hans-Jürgen | Apparatus for detection of metallic objects |
| CN2859520Y (en) * | 2005-12-29 | 2007-01-17 | 中国电子科技集团公司第五十研究所 | Shoe-inside safety detecting instrument capable of distinguishing copper, iron and aluminium |
| CN1975396A (en) * | 2006-12-28 | 2007-06-06 | 张恩伟 | In-shoe safety detector |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101556253A (en) | 2009-10-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101556253B (en) | Device and method for detecting hidden metal articles | |
| WO2008093852A3 (en) | Potential measurement apparatus and image forming apparatus | |
| EP2725973A2 (en) | Apparatus for detecting ferromagnetic objects and screening people and equipment | |
| EP2146224A2 (en) | Magnetic Body Detector | |
| CN102859873B (en) | Search equipment | |
| CA2367732A1 (en) | Electromagnetic wave generating source probing device, method therefor and analyzing method therefor | |
| AU1722797A (en) | Method to determine the direction of the Earth's magnetic field | |
| EP0697587A3 (en) | System and method for locating release of fluid from a pipeline | |
| EP0806683A3 (en) | Method for detection of magnetic substances in non-magnetic products and apparatus for the detection | |
| CN202057631U (en) | Recognition and detection instrument of metal materials in shoes | |
| US9024615B2 (en) | Non-contact voltage detector | |
| CN201477423U (en) | Intelligent vibration monitoring and protecting apparatus | |
| Liu et al. | Simulation study of the sensing field in electromagnetic tomography for two-phase flow measurement | |
| US10466280B1 (en) | Enhanced circuit and method for detecting hazardous foreign voltages on conductors | |
| GB2424286A (en) | Tamper proof utility metering | |
| WO2010151031A2 (en) | Portable detector for metals and inflammable liquids, and method for detecting metals and inflammable liquids using same | |
| CN201173929Y (en) | Detector for checking human body low site concealed metal | |
| TW201104266A (en) | Leakage current detecting device and method therefor | |
| JP2013252040A (en) | Leakage diagnostic device of noncontact power supply system | |
| EP3706528B1 (en) | An electromagnetic frequency (emf) detecting safety shovel for detecting the presence of subsurface power cables during excavation | |
| CN108120861B (en) | Intelligent ammeter electricity stealing data collector | |
| CN111880230A (en) | Improved cable detector | |
| CN207798216U (en) | Electromagnetic flowmeter magnetic disturbance detection circuit | |
| CN109856700A (en) | A kind of a variety of medium foreign matter detectors of card inserting mouth | |
| CN220270512U (en) | Voltage and electromagnetic intensity detector |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110921 Termination date: 20170409 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |