CN204028228U - Eddy conductivity survey sensor - Google Patents
Eddy conductivity survey sensor Download PDFInfo
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- CN204028228U CN204028228U CN201420420396.0U CN201420420396U CN204028228U CN 204028228 U CN204028228 U CN 204028228U CN 201420420396 U CN201420420396 U CN 201420420396U CN 204028228 U CN204028228 U CN 204028228U
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Abstract
The utility model relates to eddy conductivity survey sensor.Current vortex conductivity measurement sensors, comprising: probe and signal processing circuit, and the two is connected by stube cable (3); Described probe comprises: measuring coil (1a), compensating coil (1b), hand-held heat insulation shell, electro-magnetic screen layer, microswitch, stage clip, temperature sensor; Described signal processing circuit comprises: sinusoidal excitation unit, balancing filter unit, pre-amplifier unit, peak value holding unit, phase sensitive detection unit, digit phase rotary unit, ARM unit.Current vortex conductivity measurement sensors described in the utility model measurement result in the scope of 0 ~ 50 DEG C, not by the impact of temperature, has good suppression to Lift-off effect.
Description
Technical field:
The utility model relates to a kind of non-ferrous metal conductivity measurement technique, relates to eddy conductivity survey sensor further.
Background technology:
In recent years, along with industry and the developing rapidly of electronic industry, nonferrous materials is very important for industrial expansion.Conductivity is an important physical parameter of metal material, and the constituent of it and metal, condition of heat treatment, hardness and temperature etc. are all closely related.1873, Maxwell summed up electromagnetics system of equations, and with this system of equations for theoretical foundation, the sixties in 20th century, the method for Germany scientist current vortex successfully determines non-ferrous metal conductivity.Electric vortex method has highly sensitive compared with additive method, is easily coupled, and responds the advantages such as fast.
At present, most of eddy conductivity is measured and is used single frequency sinusoidal AC signal as pumping signal.It is low that single-frequency impedance measurement has cost, design relatively simple, sensor sensitivity advantages of higher, but be particularly used alone amplitude information the signal to noise ratio (S/N ratio) of surveying instrument can be made to be difficult to be enhanced in employing impedance method, and Lift-off effect, edge effect also have a great impact measurement result.And the crucial component part that sensor is measured as eddy conductivity, its good design is the fundamental way overcome the above problems, and is one of subject matter being engaged in EDDY CURRENT personnel care and research.In actual applications, measure in industry resolution when using more alumina-base material and copper-based material lower, easily cause error.
Therefore, need a kind of stable output, fast, within the specific limits affect by Lift-off effect little, the sensor that resolution is high.
Summary of the invention:
The purpose of this utility model be to solve existing eddy conductivity survey sensor resolution low, affect large problem by lift-off, a kind of high resolving power is proposed, there is temperature compensation function, and effectively can suppress the non-ferrous metal conductivity measurement sensors of Lift-off effect within the specific limits.
The utility model is achieved through the following technical solutions:
Eddy conductivity survey sensor, comprising: measuring sonde 1 and signal processing circuit;
Described measuring sonde comprises: measuring coil 1a, compensating coil 1b, and measuring coil is identical with compensating coil parameter, adopts the mode of difference to connect between measuring coil and compensating coil, adopts alternating current bridge structure output; Hand-held heat insulation shell, electro-magnetic screen layer, microswitch, stage clip, testing circuit, temperature sensor and stube cable; Measuring coil is placed in one end of hand-held heat insulation shell and measuring surface is exposed; Stage clip is between the first protruding 11 and second projection 12;
Described signal processing circuit comprises: sinusoidal excitation unit, balancing filter unit, pre-amplifier unit, peak value holding unit, phase sensitive detection unit, digit phase rotary unit, ARM unit.
One of preferably, described measuring coil and compensating coil are formed by enameled wire coiling, and external diameter is 8mm, and the spacing of two coils is 2mm.
Preferably two, it is inner that described electro-magnetic screen layer is placed in hand-held heat insulation shell, is connected as a single entity with hand-held heat insulation shell.
Preferably three, described temperature sensor is positioned at measuring sonde outside surface, temperature when obtaining in time measuring under the condition not being subject to the impact of operator's arm temperature around measuring sonde, imports in ARM unit in real time, revises the conductivity measuring test specimen.
Preferably four, described microswitch is fixed on housing after being placed in compensating coil.
Preferably five, described alternating current bridge comprises the resistance of two equivalences, the electric capacity of two equivalences.
Preferably six, also comprise: with the signal output interface of host computer, keyboard interface.
The course of work comprises the steps:
Step one: sensor produces the sinusoidal excitation signal of characteristic frequency;
Step 2: measuring coil contact need detect test specimen, the effect that test specimen is subject to pumping signal produces eddy current, and eddy current reacts on measuring coil, measuring coil impedance is changed, then obtains the electric signal containing customizing messages by alternating current bridge;
Step 3: the electric signal analyzing alternating current bridge output obtains the conductivity of non-ferrous metal.
The utility model is relative to the advantage of prior art:
(1) adopt eddy current detection principle, sensor bulk is less, and measuring speed is fast, and precision is high.
(2) make use of alternating current bridge to export there is linear feature, carry out a hardware calibration when dispatching from the factory after, the operation of the user greatly simplified, and also the sensitivity of sensor and measuring accuracy keep higher level always.
(3) the measuring sonde part of sensor is provided with stage clip, microswitch and electro-magnetic screen layer, press Shi Caihui when microswitch in each measurement to measure, ensure that the measuring accuracy of measuring sonde to a certain extent, decrease the measuring error caused because of the maloperation of operating personnel.
(4) also temperature sensor is installed in measuring sonde part, gathers test specimen environment temperature in time, then carry out corresponding temperature compensation, eliminate the impact of temperature for conductivity measurement.
(5) in the embodiment of recommending, by signal output interface, can realize, with the communication of host computer, realizing on-line measurement.Whole apparatus structure is simple, small volume.
Accompanying drawing illustrates:
Fig. 1 is measuring coil of the present utility model and compensating coil structural representation.In figure, 1a represents measuring coil, and 1b represents compensating coil.
Fig. 2 is the vertical view of Fig. 1.
Fig. 3 is that the utility model embodiment sensor adopts alternating current bridge structural representation.
Fig. 4 is the diagrammatic cross-section of the utility model measuring sonde structure.In figure, 1 represents measuring coil and compensating coil, and 2 represent housing, and 2a represents stage clip, and 2b represents microswitch, 2c representation temperature sensor, and 2d represents hand-held thermofin, and 3 represent stube cable, and 11 represent the first projection, and 12 represent the second projection.
Fig. 5 is the utility model embodiment sensor electrical signal structure schematic diagram.
The Impedance Transformation schematic diagram that Fig. 6 suppresses Lift-off effect to adopt for the utility model sensor.
Embodiment:
As Figure 1-Figure 5, sensor comprises the utility model sensor construction block diagram:
Measuring sonde 1 and signal processing circuit, the two is connected by stube cable 3;
Described measuring sonde comprises: measuring coil 1a, compensating coil 1b, and measuring coil is identical with compensating coil parameter, adopts the mode of difference to connect between measuring coil and compensating coil, adopts alternating current bridge structure output; Hand-held heat insulation shell, electro-magnetic screen layer, microswitch, stage clip, testing circuit, temperature sensor and stube cable;
Measuring coil is placed in one end of hand-held heat insulation shell and measuring surface is exposed; Stage clip is between the first protruding 11 and second projection 12;
Described signal processing circuit comprises: sinusoidal excitation unit, balancing filter unit, pre-amplifier unit, peak value holding unit, phase sensitive detection unit, digit phase rotary unit, ARM unit, signal output interface, keyboard interface.
Described measuring coil and compensating coil are formed by enameled wire coiling, and external diameter is 8mm, and the spacing of two coils is 2mm; It is inner that described electro-magnetic screen layer is placed in hand-held heat insulation shell, is connected as a single entity with hand-held heat insulation shell; Described temperature sensor is positioned at measuring sonde outside surface, and temperature when obtaining in time measuring under the condition not being subject to the impact of operator's arm temperature around measuring sonde, imports in ARM unit in real time, revises the conductivity measuring test specimen; After described microswitch is placed in compensating coil, be fixed on housing; Described alternating current bridge comprises the resistance of two equivalences, the electric capacity of two equivalences.
The ac-excited signal of characteristic frequency is produced, in pumping signal input measurement probe by sinusoidal excitation unit.
Stage clip, between the first projection and the second projection, is only pressed Shi Caihui at microswitch at every turn and is measured, ensure that the measuring accuracy of measuring sonde to a certain extent, decrease the measuring error caused because of the maloperation of operating personnel.
AC measuring bridge structure as shown in Figure 3, electric capacity add the output sensitivity that effectively can improve alternating current bridge.Simple alternating current pumping signal enters electric bridge by V1, V2 ground connection, and signal is entered in preposition differential operational amplifier by V3 and V4.
Measuring coil loads sinusoidal alternating signal during measurement, act on test specimen and make it produce eddy current, the eddy current of generation reacts on measuring coil, and measuring coil impedance is changed.The complex information comprised in impedance includes the conductivity information of test specimen and one_to_one corresponding, and the change of measuring coil impedance is converted to electric signal by alternating current bridge and exports.
Amplitude information and the phase information of signal is obtained by the peak value holding unit in signal processing circuit and phase sensitive detection unit.Utilize the suppression of method realization for Lift-off interference signal of impedance transformation, principle as shown in Figure 6, eddy conductivity survey sensor changes with the impedance point (0,1) of the mode of near linear to unloaded coil with being increased in normalized impedance plane of lift-off distance.According to the principle of impedance analysis, choose the component of measurement impedance in lift-off linear vertical direction, effectively can suppress Lift-off effect within the specific limits.In Fig. 6, A is the normalized impedance point of measuring coil when not having lift-off, and B is the normalized impedance point of the measuring coil after having certain lift-off.Move in a linear fashion owing to being similar to the increase of lift-off distance, no matter so lift-off is apart from being much when measuring within the specific limits, the normalized impedance point of its measuring coil recorded all is positioned at (as C) on the near linear of AP.Make the parallel lines OP ' of AP from an O, then make the vertical line of OP ' respectively from A, B, C point, OA, OB, OC of obtaining are each unequal, but AA '=BB '=CC '.From above formula, owing to being subject to the impact of Lift-off effect, during actual measurement, the resistance value OA of measuring coil there occurs change, but by suitable phase transition, extracts the size that signal AA ' (or BB ', CC ') can reflect OA (or OB, OC) signal.So by the amplitude that records measuring coil impedance variation and phase place, calculate impedance at lift-off straight line component in vertical direction, just can realize the suppression for Lift-off effect.Amplitude after ARM cell processing and phase information carry out temperature adjustmemt again, import host computer into afterwards by signal output interface.
The conductivity of sensor application electric vortex method to non-ferrous metal is measured, and testing result by the impact of temperature, does not have certain inhibiting effect to Lift-off effect.And sensor has stronger antijamming capability, highly sensitive, be applicable to nonferrous materials conductivity, resistivity value is measured, unknown non-ferrous metal carries out identifying and classify, the heat treated checking of production period and detect the fields such as cause thermal damage when using.
Claims (7)
1. eddy conductivity survey sensor, is characterized in that, comprising: measuring sonde and signal processing circuit, and the two is connected by stube cable (3);
Described measuring sonde comprises: measuring coil (1a); Compensating coil (1b); Measuring coil is identical with compensating coil parameter, adopts the mode of difference to connect between measuring coil and compensating coil, adopts alternating current bridge structure output; Hand-held heat insulation shell; Electro-magnetic screen layer; Microswitch; Stage clip; Temperature sensor and stube cable;
Measuring coil is placed in one end of hand-held heat insulation shell and measuring surface is exposed;
Stage clip is positioned between the first projection (11) and the second projection (12);
Described signal processing circuit comprises: sinusoidal excitation unit, balancing filter unit, pre-amplifier unit, peak value holding unit, phase sensitive detection unit, digit phase rotary unit, ARM unit.
2. eddy conductivity survey sensor according to claim 1, it is characterized in that: described measuring coil and compensating coil are formed by enameled wire coiling, external diameter is 8mm, and the spacing of two coils is 2mm.
3. eddy conductivity survey sensor according to claim 1, is characterized in that: it is inner that described electro-magnetic screen layer is placed in hand-held heat insulation shell, is connected as a single entity with hand-held heat insulation shell.
4. eddy conductivity survey sensor according to claim 1, it is characterized in that: described temperature sensor is positioned at measuring sonde outside surface, temperature when obtaining in time measuring under the condition not being subject to the impact of operator's arm temperature around measuring sonde, import in ARM unit in real time, the conductivity measuring test specimen is revised.
5. eddy conductivity survey sensor according to claim 1, is characterized in that: described microswitch is fixed on housing after being placed in compensating coil.
6. eddy conductivity survey sensor according to claim 1, it is characterized in that, described alternating current bridge comprises the resistance of two equivalences, the electric capacity of two equivalences.
7. eddy conductivity survey sensor according to claim 1, is characterized in that, also comprise: with the signal output interface of host computer, keyboard interface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420420396.0U CN204028228U (en) | 2014-07-28 | 2014-07-28 | Eddy conductivity survey sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420420396.0U CN204028228U (en) | 2014-07-28 | 2014-07-28 | Eddy conductivity survey sensor |
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| CN204028228U true CN204028228U (en) | 2014-12-17 |
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| CN201420420396.0U Expired - Fee Related CN204028228U (en) | 2014-07-28 | 2014-07-28 | Eddy conductivity survey sensor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104142431A (en) * | 2014-07-28 | 2014-11-12 | 天津大学 | Eddy current conductivity measuring sensor |
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2014
- 2014-07-28 CN CN201420420396.0U patent/CN204028228U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104142431A (en) * | 2014-07-28 | 2014-11-12 | 天津大学 | Eddy current conductivity measuring sensor |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141217 Termination date: 20160728 |