CN2484572Y - Capacitance-date collection sensor - Google Patents
Capacitance-date collection sensor Download PDFInfo
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- CN2484572Y CN2484572Y CN 01220419 CN01220419U CN2484572Y CN 2484572 Y CN2484572 Y CN 2484572Y CN 01220419 CN01220419 CN 01220419 CN 01220419 U CN01220419 U CN 01220419U CN 2484572 Y CN2484572 Y CN 2484572Y
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- capacitance
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- amplifier
- electric capacity
- circuit
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Abstract
The utility model discloses a capacitance-data collection sensor. The sensor comprises an insulation pipeline distributed evenly with a plurality of sensitive electrodes on the outside wall. The sensitive electrodes are provided with a shielding cover, and a radial electrode is arranged in the inside wall of the shielding cover between the intervals of a plurality of sensitive electrodes. A strip-type data collection capacitance/voltage converter circuit board that is connected through cable is fixed on the radial electrode. The utility model reduced the capacitance formed between lead wire and ground, which can improve measuring precision; the anti-disturbance ability of outer lead wire is reinforced, which improved the reliability of the system; the capacitance/voltage converting circuit is arranged under the shielding cover, which simplified the outer circuit and decreased the volume.
Description
The utility model relates to the measurement electric variable, relates in particular to a kind of capacitance data pick-up transducers.
The structure of present capacitance tomography system and weak point thereof: capacitance chromatography imaging (ElectricalCapacitance Tomography, brief note ECT) technology is a kind of polyphasic flow parameter detecting technology that begins to grow up from the mid-80.Its principle of work as shown in Figure 1.It distributes by the specific inductive capacity of medium on the capacitance sensing acquisition tube section and obtains the image of dielectric distribution.It mainly is made up of capacitive transducer, capacitance data acquisition system and image reconstruction microcomputer three parts.Sensor has a plurality of (the being generally 12) electrode that is evenly distributed on the isolated pipe outer wall to constitute, and can form electric capacity between these electrodes, and when the space distribution of multiphase medium in the pipeline changed, these electric capacity also can change; Data acquisition system (DAS) then is converted into these electric capacity digital quantity and sends computing machine to; Computing machine is then finished image reconstruction work according to certain image reconstruction algorithm.
In present system, no testing circuit in the sensor, detecting electrode is connected to the capacitance data acquisition system by the heart yearn of shielded cable, the shielding layer grounding of shielded cable.In this measuring system, owing to can form electric capacity between the heart yearn of shielded cable and screen layer, when shielded cable was moved, this electric capacity can change.Though this changes in capacitance amount is very little, remain sizable with respect to the measured capacitance of native system.When using at the scene, this system can cause bigger measuring error if the position of this cable is moved.This makes this system be difficult to be applied to actual industrial environment.In addition, even the position of cable is not moved, the existence of this electric capacity also can cause the reduction of measuring speed.The existence of this cable is that this system is difficult to one of major obstacle of industrial practicability.
The capacitance measurement method that is fit to be applied to electrical capacitance tomography mainly contains two kinds of method of charge transfer and AC method.These two kinds of circuit all are that electric capacity is carried out continuous discharging and recharging in essence, and the size that discharges and recharges the electric current of formation has been represented capacitance size.And this electric current that discharges and recharges formation is pulsed, thereby filtering in addition.And filter time constant is big, good wave filtering effect then, but the capacitance measurement time is long.Otherwise the capacitance measurement time is short, but noise is big.The selection of time constant often is in the contradiction.Acquisition speed was 100 width of cloth/seconds the soonest.
The purpose of this utility model provides a kind of sensor external cable that suppresses and moves measurement result interference, high-speed, low noise capacitance data pick-up transducers.
In order to achieve the above object, the utility model is taked following measures:
The capacitance data pick-up transducers comprises isolated pipe, a plurality of sensitive electrodes evenly distribute on the isolated pipe outer wall, sensitive electrode is provided with radome outward, between radome inwall and a plurality of sensitive electrode interval, be provided with radial electrode, it is characterized in that on radial electrode, being fixed with strip data acquisition electric capacity/voltage translator circuit plate, and connect by winding displacement.
The utility model has the advantages that:
1) reduced the electric capacity that forms between lead-in wire and ground.Electric capacity/voltage conversion circuit is placed under the radome, shortened the length of lead-in wire greatly.This outer lead adopts non-shielding line to be equivalent to increase distance between lead-in wire and ground, can further reduce to go between and ground between the electric capacity that forms, thereby can improve measuring accuracy;
2) antijamming capability of outside lead strengthens greatly.In what transmit on the outside winding displacement is channel control signals and the voltage signal of representing capacitance measurements, move it and can not exert an influence, thereby make the reliability of system increase measurement result;
3) volume can be reduced, and maintenance job can be simplified.Electric capacity/voltage conversion circuit is placed under the radome, make the circuit of exterior section simplify greatly.In addition because each electric capacity/voltage conversion circuit is identical, if certain wiring board damage, then getting final product with the backup board replacing.
Below in conjunction with accompanying drawing the utility model is elaborated.
Fig. 1 is the capacitance tomography system synoptic diagram;
Fig. 2 is a capacitance data pick-up transducers structural representation;
Fig. 3 is the square frame electrical schematic diagram of data acquisition electric capacity/electric pressure converter;
Fig. 4 is the electrical schematic diagram of data acquisition electric capacity/electric pressure converter;
Fig. 5 is the sequential synoptic diagram of capacitance measurement circuit.
The capacitance data pick-up transducers comprises isolated pipe 2 among Fig. 2, a plurality of sensitive electrodes 3 evenly distribute on the isolated pipe outer wall, sensitive electrode is provided with radome 4 outward, between radome inwall and a plurality of sensitive electrode interval, be provided with radial electrode 1, it is characterized in that on radial electrode, being fixed with strip data acquisition electric capacity/voltage translator circuit plate 5, and connect by winding displacement.
The control signal that transmits by the measurement plate of sensor outside among Fig. 3 and be connected to code translator by the module's address of dial switch setting, the output of code translator is connected to control exciting signal source and electric capacity/electric pressure converter, and sensing electrode is connected to control exciting signal source and capacitance voltage converter.The output of electric capacity/electric pressure converter is sent through the electronic switch of code translator control.
The physical circuit of strip data acquisition electric capacity/voltage translator circuit plate 5 is among Fig. 4: measured capacitance C
xOne termination exciting signal source V
iOne termination amplifier U
1Inverting input.Capacitor C
fWith electronic switch S
1Back one termination amplifier U in parallel
1The output of inverting input one this amplifier of termination.Amplifier U
1In-phase end ground connection.Capacitor C
1And C
2An end ground connection, the other end is respectively at electronic switch S
2, S
3An end be connected to impact damper U respectively after linking to each other
2, U
3Input end.Electronic switch S
2, S
3The other end and amplifier U
1Output link to each other.Impact damper U
2, U
3Output be connected to instrument amplifier U respectively
4The positive and negative input end, instrument amplifier is output as the output of metering circuit.
C
xBe measured capacitance, C
As, C
BsBe the electric capacity that forms between two electrodes of electric capacity and ground.S
1, S
2, S
3Be electronic switch.U
1Be the operational amplifier (as TL081) of high input resistance, U
2, U
3Be the impact damper that amplifier constitutes, its input and output enlargement factor is 1.U
4Be instrument amplifier (as AD620).V
iBe exciting signal source, it is two level of output height only.U
1, C
f, S
1Constitute charge amplifier.S
2, U
2And S
3, U
3Constitute sampling holder (S/H) respectively.When starting working, V
iBe high level, S
1Closure, sampling holder all are in following state.Because S
1Closure, U
1Be output as 0V.At t=t
1Constantly, S
1Disconnect, in the ideal case, U
1It is constant that output still remains 0V, but since the electric charge injection effect, C
fOn have electric charge, make U
1Output V
1Reduce (electronic switch that has also may make its rising), establishing this voltage is V
LAt t
2Constantly, U
1Export stable, and V
2Followed V
1Variation, S
3Disconnect, with voltage V
LRemain on U
2Output terminal.Subsequently at t
3Constantly, driving voltage reduces, and this voltage charges to measured capacitance, and the iunjected charge amount is:
Q=Δ V
i *C
xThis flow of charge is stored in C behind the virtual earth end of amplifier
fOn, this moment U
1Be output as:
V
H=V
L-Q/C
fThis voltage is at t
4Constantly be held in V
3End, then instrument amplifier U
4Be output as
V
4=V
H-V
L=-Δ V
i *C
x/ C
fThat is, its output voltage and C
xBe directly proportional.
Measured capacitance C
xTwo electrodes and ground between also can form stray capacitance C respectively
AsAnd C
Bs ', testing circuit should be able to suppress the influence of their existence to measurement result.Capacitor C
AsWith driving source V
iLink to each other, its existence can not influence the electric current by measured capacitance.C
BsTwo ends be in the imaginary short state.Its existence can not exert an influence to output yet.
Claims (3)
1. capacitance data pick-up transducers, it comprises isolated pipe [2], a plurality of sensitive electrodes [3] evenly distribute on the isolated pipe outer wall, sensitive electrode is provided with radome [4] outward, between radome inwall and a plurality of sensitive electrode interval, be provided with radial electrode [1], it is characterized in that on radial electrode, being fixed with strip data acquisition electric capacity/voltage translator circuit plate [5], and connect each circuit board by winding displacement.
2. a kind of capacitance data pick-up transducers according to claim 1, the circuit that it is characterized in that said bar shaped data acquisition electric capacity/voltage translator circuit plate [5] is: the control signal that is transmitted by the measurement plate of sensor outside and be connected to code translator by the module's address of dial switch setting, the output of code translator is connected to control exciting signal source and electric capacity/electric pressure converter, sensing electrode is connected to control exciting signal source and capacitance voltage converter, and the output of electric capacity/electric pressure converter is sent through the electronic switch of code translator control.
3. a kind of capacitance data pick-up transducers according to claim 1 and 2 is characterized in that the physical circuit of said strip data acquisition electric capacity/voltage translator circuit plate [5] is: measured capacitance C
xOne termination exciting signal source V
iOne termination amplifier U
1Inverting input, capacitor C
fWith electronic switch S
1Back one termination amplifier U in parallel
1The output of inverting input one this amplifier of termination, amplifier U
1In-phase end ground connection, capacitor C
1And C
2An end ground connection, the other end is respectively at electronic switch S
2, S
3An end be connected to impact damper U respectively after linking to each other
2, U
3Input end, electronic switch S
2, S
3The other end and amplifier U
1Output link to each other impact damper U
2, U
3Output be connected to instrument amplifier U respectively
4The positive and negative input end, instrument amplifier is output as the output of metering circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01220419 CN2484572Y (en) | 2001-03-29 | 2001-03-29 | Capacitance-date collection sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01220419 CN2484572Y (en) | 2001-03-29 | 2001-03-29 | Capacitance-date collection sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2484572Y true CN2484572Y (en) | 2002-04-03 |
Family
ID=33638027
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01220419 Expired - Fee Related CN2484572Y (en) | 2001-03-29 | 2001-03-29 | Capacitance-date collection sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2484572Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102435864A (en) * | 2011-11-22 | 2012-05-02 | 常熟市董浜镇华进电器厂 | Current sensor capacitance measurement circuit |
| CN105738212A (en) * | 2016-01-29 | 2016-07-06 | 河海大学 | Rock tri-axial test crack extension observation device based on electrical capacitance tomography technique |
| CN105842475A (en) * | 2016-03-21 | 2016-08-10 | 山西泫氏实业集团有限公司 | Non-intruding type waterpower test method in building draining system |
| CN108152341A (en) * | 2017-12-05 | 2018-06-12 | 浙江大学 | A kind of cryogen Bottomhole pressure capacitance chromatography imaging device |
| CN110879313A (en) * | 2019-11-20 | 2020-03-13 | 广州钰芯传感科技有限公司 | Micro-capacitance measuring circuit and measuring method of capacitance sensor |
-
2001
- 2001-03-29 CN CN 01220419 patent/CN2484572Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102435864A (en) * | 2011-11-22 | 2012-05-02 | 常熟市董浜镇华进电器厂 | Current sensor capacitance measurement circuit |
| CN105738212A (en) * | 2016-01-29 | 2016-07-06 | 河海大学 | Rock tri-axial test crack extension observation device based on electrical capacitance tomography technique |
| CN105842475A (en) * | 2016-03-21 | 2016-08-10 | 山西泫氏实业集团有限公司 | Non-intruding type waterpower test method in building draining system |
| CN108152341A (en) * | 2017-12-05 | 2018-06-12 | 浙江大学 | A kind of cryogen Bottomhole pressure capacitance chromatography imaging device |
| CN108152341B (en) * | 2017-12-05 | 2020-09-25 | 浙江大学 | Low-temperature fluid in-pipe flowing capacitance tomography device |
| CN110879313A (en) * | 2019-11-20 | 2020-03-13 | 广州钰芯传感科技有限公司 | Micro-capacitance measuring circuit and measuring method of capacitance sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |