CN102809572A - System for measuring solution concentration by using perturbation method - Google Patents
System for measuring solution concentration by using perturbation method Download PDFInfo
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- CN102809572A CN102809572A CN2012102817018A CN201210281701A CN102809572A CN 102809572 A CN102809572 A CN 102809572A CN 2012102817018 A CN2012102817018 A CN 2012102817018A CN 201210281701 A CN201210281701 A CN 201210281701A CN 102809572 A CN102809572 A CN 102809572A
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Abstract
The invention relates to the technical field of solution parameter measurement and relates to a system for measuring a solution concentration by using a perturbation method. The system comprises a microwave resonant cavity sensor, a wave detector, a voltage-controlled oscillator, a frequency tracking module, a frequency measuring module and a main control processing module, wherein frequency modulated signals generated by the voltage-controlled oscillator under the control of the main control processing module are divided into two ways; one way is mixed with local oscillator signals so as to generate difference frequency signals; the other way is led into a waveguide and is transmitted and coupled by the waveguide to be coupled into a resonant cavity; reflecting signal inside the resonant cavity enters the wave detector through a circulator; modulating signals output from the wave detector are transmitted into the frequency tracking module; the frequency tracking module comprises an amplitude discriminating module and a phase discriminating module; the main control processing module is used for controlling the carrier frequency of the voltage-controlled oscillator; the output of the frequency measuring module is accessed to the main control processing module; and the main control processing module obtains the corresponding relationship between a frequency offset and a solution concentration. The system can realize accurate and real-time measurement to the solution concentration.
Description
Technical field
The present invention relates to a kind ofly be used to measure the control system of solution concentration, can accurately measure and control, belong to technical field of measurement and test solution concentration based on perturbation method.
Background technology
There is exigence in each field such as industrial and agricultural production in modern times, medicine, chemical industry, food for the detection of strength of fluid wide region, hopes to occur a kind of simple in structure, and the system that new liquid concentration accurately detects is measured in control easily.
Solution concentration is to calculate according to the content of solute in solution, and the variation solution concentration owing to the solute amount in practical application also changes.The metering system of solution concentration is divided into direct measurement and indirect metering system.Directly extract in the measured in solution solution solvent and solutes content and be fundamental method, but owing to extract the state that solution can have influence on solution, suitablely need to be applied in the strict environment of controlling solution state; Another kind is to adopt picnometer to measure the method for solution concentration, and main dependence is artificial to be accomplished.These two kinds of methods belong to the direct metering system of solution concentration.Indirectly metering system then is that the characteristic with solution is a foundation, weigh what of solute amount in the solution like the conductivity size of solution, but this method can only be applied to electrolyte solution, has limited its measurement range.
Application for a patent for invention 201210009379.3 before the applicant provides a kind of microwave resonance cavity sensor and measuring system that is used to measure solution concentration; The measuring principle of this kind sensor and measuring system is that the relation according to the specific inductive capacity of solution and solutes content realizes, can overcome above-mentioned deficiency, has simple in structure; Applied widely; But the advantage of on-line measurement, this patented claim has mainly provided the microwave resonance cavity sensor, and measuring system; Just provided the most basic a kind of metering system, its measuring accuracy is still waiting to improve.
Summary of the invention
The object of the present invention is to provide a kind of measuring system that is applicable to aforesaid microwave resonance cavity sensor solution concentration measurement, can realizes and real-time measurement accurate to solution concentration.Technical scheme of the present invention is following:
A kind of measuring system that is used to measure solution concentration; Comprise microwave resonance cavity sensor, wave detector, voltage controlled oscillator, frequency-tracking module and frequency measurement module and master control processing module; Described microwave cavity sensor comprises that set inside has a resonator cavity that is used to hold the sense channel of solution to be measured; On the sidewall of resonator cavity, offer coupling aperture, be provided with at the coupling aperture place one be used for the Transmission Microwave signal waveguide, the FM signal that described voltage controlled oscillator produces under the control of master control processing module is divided into two-way; One the tunnel with the local oscillation signal mixing, produce difference frequency signal; Another road imports waveguide, is coupled to resonator cavity through waveguide, and the reflected signal of resonator cavity gets into wave detector through circulator again, and the restituted signal of being exported by wave detector is admitted to the frequency-tracking module; The frequency-tracking module comprises amplitude identification module and phase place identification module, and the amplitude identification module is differentiated the amplitude of the restituted signal of wave detector output, judged whether resonator cavity reaches resonant condition, and its identification result is admitted to the main control processing module; The phase place identification module is used to differentiate the phase relation of modulation signal and restituted signal; Its identification result is admitted to the master control processing module; By the master control processing module when not reaching resonant condition; Obtain the carrier frequency of voltage controlled oscillator and the magnitude relationship of resonance frequency according to identification result, and the carrier frequency of voltage controlled oscillator is adjusted, it is equated with the resonance frequency of resonator cavity; The frequency measurement module, in order to measure the frequency of frequency mixer output difference frequency signal, its output is admitted to the master control processing module, is obtained the corresponding relation of frequency offset and solution concentration by the master control processing module.
As preferred implementation; Described amplitude identification module comprises rectifying and wave-filtering, amplifier and first comparer that links to each other successively, and amplifier adopts low noise high precision operating amplifier OP07, and it is 10 times that enlargement factor is set; Comparer 1 is selected LM339 for use, and comparative voltage is 2V; Described phase place identification module comprises multiplier, low-pass filter and second comparer, and the restituted signal and the modulation signal of wave detector output are admitted to multiplier, exports digital signal behind the output signal process low-pass filter of multiplier and second comparer.
The present invention is used to measure the measuring system of solution concentration, has following advantage and good effect:
1, the present invention utilizes the resonator cavity perturbation principle to measure, and can measure more multi-class solution, and reliable measurement property is high, has good real-time.
2, the present invention is owing to through solution concentration being changed the analysis and the processing of the resonator cavity resonance frequency shift of front and back, can carry out the detection of wide region to the concentration of detected solution.
3, the present invention is no more than 500 μ W because the microwave signal power of transmission is very little, far below the radiation power of mobile phone, therefore can not cause any infringement to measured matter and surrounding environment.
4, resonator mode block structure of the present invention is simple, easy to use, and is low to environment requirement.
Description of drawings
Below in conjunction with accompanying drawing the present invention is further described.
Fig. 1 is the structural drawing of resonator sensor.
The system architecture diagram that Fig. 2 adopts for the present invention.
Fig. 3 is a frequency-tracking system architecture diagram of the present invention.
Fig. 4 is a main program flow chart of the present invention.
Embodiment
The more detailed content of microwave resonance cavity sensor that relevant the present invention adopts can be referring to patented claim 201210009379.3 formerly.Combine Fig. 1 that this sensor is carried out simple declaration, this sensor comprises resonator cavity 3 at present; At resonator cavity 3 middle parts one glass tube 5 is set, this glass tube interior zone 6 is in order to place detected solution; Have a circular hole 1 in resonator cavity 3 sidewall centers, resonator cavity carries out the transmission of microwave signal through this circular hole and rectangular waveguide coupling; Dog screw 4 is used for top cover and cavity 3 is fixing.
The microwave signal that is produced by microwave source imports waveguide through circulator; Be coupled to resonator cavity through waveguide; The reflected signal of resonator cavity imports wave detector through circulator, through tracking and the measurement of outside treatment circuit to resonance frequency, just can obtain the relation of resonance frequency and specific inductive capacity.
Rectangular waveguide TE is adopted in the excitation of resonator cavity
10Ripple is as driving source, and cylindrical cavity and rectangular waveguide through the aperture coupling, parallel the broadside of rectangular waveguide and the axis direction of resonator cavity at waveguide terminal, and the coupling aperture is opened the sidewall center at resonator cavity.Has only the Hx component at the terminal of rectangular waveguide, Hx component and TE
011The Hz component of mould cylindrical cavity is consistent, so this coupling scheme can encourage TE
011Mould.TE
011Pattern and TM
111Pattern is the degeneracy wave mode, at excitation port TM
111The Hz component of mould is zero, can not be energized.So, adopt this energisation mode to suppress TM
111The generation of mould.
Referring to Fig. 2, resonator cavity is for being operated in TE
011The reflective resonator cavity of the sealing of pattern; When the concentration of measured solution in the chamber changed, the resonance frequency of resonator cavity squinted, and the FM signal that VCO produces is divided into two-way through directional coupler: the one tunnel gets into frequency mixer; With the local oscillation signal (fixed frequency that produces by crystal oscillator; Its value equals the resonance frequency before the perturbation) mixing, produce difference frequency signal (be that the difference frequency signal frequency equals the poor of FM signal frequency and local oscillation signal frequency, also can be described as intermediate-freuqncy signal); Another road imports waveguide through circulator; Be coupled to resonator cavity through waveguide; The reflected signal of resonator cavity (also can be described as amplitude-modulated signal) gets into wave detector through circulator again; Wave detector output restituted signal, the frequency-tracking module equates it according to the carrier frequency of the relation control VCO output FM signal of restituted signal and modulation signal all the time with the resonance frequency of resonator cavity.The reference frequency of frequency mixer is the resonance frequency 9.6GHz of resonator cavity; The difference frequency signal that is produced by frequency mixer is the frequency shift (FS) of perturbation front and back; Difference frequency signal after the overfrequency measuring system is measured its frequency, just can obtain the concentration of solution through the shaping amplification at last through data processing.
Because the loss of electromagnetic wave in liquid descends the quality factor of resonator cavity, reaches designing requirement for making figure of merit value, must reduce electromagenetic wave radiation loss and cavity inner surface loss as much as possible.With the material of copper as resonator cavity, closed at both ends reduces electromagnetic leakage on the one hand; On the other hand will be at the resonator cavity electroplate, and make inside surface smooth, reduce the loss of conductor.
Referring to Fig. 3, the frequency-tracking module comprises amplitude identification module and phase place identification module, and the discriminating of amplitude realizes that through rectifying and wave-filtering, amplifier and comparer 1 detection of phase place realizes through multiplier, LPF and comparer 2.
Rectification filtering part is divided into accurate full-wave rectification; Amplifier adopts low noise high precision operating amplifier OP07; It is 10 times that enlargement factor is set, and comparer 1 is selected LM339 for use, and comparative voltage is 2V; As long as two input terminal voltage signal difference 10mV output states just can change, the output of comparer is through converting digital signal into door.When resonator cavity resonance, be about 70mV with the door output voltage, reading in single-chip microcomputer is 0; When the resonator cavity off resonance, with the door output voltage be 5V, reading in single-chip microcomputer is 1, single-chip microcomputer judges according to the digital signal of reading in whether resonator cavity is in resonant condition.
When resonator cavity not during resonance; The restituted signal and the modulation signal of wave detector output pass through multiplier; Multiplier is selected analog multiplier MC1496 for use, and the output signal of multiplier is through low-pass filter and comparer 2 back output digital signals, and master control processing module (the present invention adopts the AT89S52 chip) is judged the magnitude relationship of carrier frequency and resonance frequency according to the digital signal of reading in; And then increase or reduce carrier frequency, make resonator cavity reach resonant condition.
The D/A converter model is AD5530, and reference voltage is 10V, and its conversion accuracy is 10/ (212-1)=0.0024V, and the output frequency that is scaled VCO is changed to 2.4KHz, and the input signal of D/A converter is exported by the master control processing module.
Frequency mixer is the high level double balanced mixer, amplifies the shaping circuit of shaping unit for being made up of 555 timers, and frequency measurement with constant-precision methods such as frequency measurement module employing, logical process partly select for use fpga chip EP2C20 and Verilog HDL language to realize.The output data of frequency measurement module is divided and 3 times 24 bit frequency values to be read in single-chip microcomputer by the master control processing module sel [1..0] that transmits control signal, and the P0 mouth by single-chip microcomputer reads in 8 bit data at every turn.Run through the back and provide the CLR reset signal, make counter O reset, prepare counting next time by single-chip microcomputer.
The present invention is through following the tracks of and measure the resonance frequency shift amount of resonator cavity perturbation front and back; Can obtain the specific inductive capacity of medium in the chamber, because when temperature-resistant, the specific inductive capacity of certain concentration solution is certain; Therefore, just can obtain the corresponding solution concentration of specific inductive capacity through the master control handling procedure.
Claims (3)
1. measuring system that is used to measure solution concentration; Comprise microwave resonance cavity sensor, wave detector, voltage controlled oscillator, frequency-tracking module and frequency measurement module and master control processing module; Described microwave cavity sensor comprises that set inside has a resonator cavity that is used to hold the sense channel of solution to be measured, on the sidewall of resonator cavity, offers coupling aperture, be provided with at the coupling aperture place one be used for the Transmission Microwave signal waveguide; It is characterized in that; The FM signal that described voltage controlled oscillator produces under the control of master control processing module is divided into two-way, the one tunnel with the local oscillation signal mixing, produce difference frequency signal; Another road imports waveguide, is coupled to resonator cavity through waveguide, and the reflected signal of resonator cavity gets into wave detector through circulator again, and the restituted signal of being exported by wave detector is admitted to the frequency-tracking module; The frequency-tracking module comprises amplitude identification module and phase place identification module, and the amplitude identification module is differentiated the amplitude of the restituted signal of wave detector output, judged whether resonator cavity reaches resonant condition, and its identification result is admitted to the main control processing module; The phase place identification module is used to differentiate the phase relation of modulation signal and restituted signal; Its identification result is admitted to the master control processing module; By the master control processing module when not reaching resonant condition; Obtain the carrier frequency of voltage controlled oscillator and the magnitude relationship of resonance frequency according to identification result, and the carrier frequency of voltage controlled oscillator is adjusted, it is equated with the resonance frequency of resonator cavity; The frequency measurement module, in order to measure the frequency of frequency mixer output difference frequency signal, its output is admitted to the master control processing module, is obtained the corresponding relation of frequency offset and solution concentration by the master control processing module.
2. the measuring system that is used to measure solution concentration according to claim 1; It is characterized in that; Described amplitude identification module comprises rectifying and wave-filtering, amplifier and first comparer that links to each other successively, and amplifier adopts low noise high precision operating amplifier OP07, and it is 10 times that enlargement factor is set; Comparer 1 is selected LM339 for use, and comparative voltage is 2V.
3. the measuring system that is used to measure solution concentration according to claim 1; It is characterized in that; Described phase place identification module; Comprise multiplier, low-pass filter and second comparer, the restituted signal and the modulation signal of wave detector output are admitted to multiplier, export digital signal behind the output signal process low-pass filter of multiplier and second comparer.
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105021885A (en) * | 2015-05-15 | 2015-11-04 | 天津大学 | Frequency tracking measurement device for microwave resonant cavity |
| CN105067654A (en) * | 2015-09-11 | 2015-11-18 | 天津大学 | Single-mode resonant cavity sensor-based solution concentration measurement method |
| CN107014419A (en) * | 2017-03-23 | 2017-08-04 | 西安交通大学 | Quartz based on FPGA+SOPC shakes beam resonant transducer test system |
| CN108562798A (en) * | 2018-07-02 | 2018-09-21 | 中国科学院东北地理与农业生态研究所 | A method of measuring lossy material dielectric constant |
| CN109374691A (en) * | 2018-10-19 | 2019-02-22 | 沈阳师范大学 | The device and method of microwave measurement graphite alkenes Dielectric constant changing rule |
| CN111610385A (en) * | 2019-02-25 | 2020-09-01 | 川升股份有限公司 | Electrical parameter measuring system |
| CN113418939A (en) * | 2021-07-01 | 2021-09-21 | 北京普瑞迈科技术有限公司 | Microwave resonance structure and system for measuring concentration of solutions such as rubber latex |
| CN113465633A (en) * | 2021-08-09 | 2021-10-01 | 东南大学 | Microwave resonant sensor for software intelligent detection and frequency shift detection method thereof |
| CN114152634A (en) * | 2021-10-25 | 2022-03-08 | 广西大学 | Novel intelligent measurement system and method for brix |
| CN115220370A (en) * | 2021-04-16 | 2022-10-21 | 天津大学 | FPGA-based solution concentration real-time monitoring system |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1034431A (en) * | 1989-01-04 | 1989-08-02 | 兰州大学 | A kind of device and method of measuring solution concentration |
| JPH0580001A (en) * | 1991-09-20 | 1993-03-30 | Daipoole:Kk | Device for measuring amount of physical properties |
| US5864239A (en) * | 1996-12-03 | 1999-01-26 | Wagner International | Apparatus for measuring a powder mass flow |
| CN201060170Y (en) * | 2007-06-20 | 2008-05-14 | 中国电子科技集团公司第四十一研究所 | Cigarette denseness microwave testing apparatus |
| CN201133259Y (en) * | 2007-12-19 | 2008-10-15 | 华北电力大学 | High precision steam turbine exhaust steam moisture on-line measurement device |
| CN101614681A (en) * | 2009-06-19 | 2009-12-30 | 周建明 | Micro-water content test system based on resonant cavity perturbation method |
| CN101943653A (en) * | 2009-07-10 | 2011-01-12 | 中国科学院沈阳自动化研究所 | Device and method for quickly detecting density of non-metallic substance by resonant cavity perturbation method |
| CN102590230A (en) * | 2012-01-12 | 2012-07-18 | 天津大学 | Microwave resonant cavity sensor and measurement system for measuring concentration of solution |
-
2012
- 2012-08-08 CN CN2012102817018A patent/CN102809572A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1034431A (en) * | 1989-01-04 | 1989-08-02 | 兰州大学 | A kind of device and method of measuring solution concentration |
| JPH0580001A (en) * | 1991-09-20 | 1993-03-30 | Daipoole:Kk | Device for measuring amount of physical properties |
| US5864239A (en) * | 1996-12-03 | 1999-01-26 | Wagner International | Apparatus for measuring a powder mass flow |
| CN201060170Y (en) * | 2007-06-20 | 2008-05-14 | 中国电子科技集团公司第四十一研究所 | Cigarette denseness microwave testing apparatus |
| CN201133259Y (en) * | 2007-12-19 | 2008-10-15 | 华北电力大学 | High precision steam turbine exhaust steam moisture on-line measurement device |
| CN101614681A (en) * | 2009-06-19 | 2009-12-30 | 周建明 | Micro-water content test system based on resonant cavity perturbation method |
| CN101943653A (en) * | 2009-07-10 | 2011-01-12 | 中国科学院沈阳自动化研究所 | Device and method for quickly detecting density of non-metallic substance by resonant cavity perturbation method |
| CN102590230A (en) * | 2012-01-12 | 2012-07-18 | 天津大学 | Microwave resonant cavity sensor and measurement system for measuring concentration of solution |
Non-Patent Citations (2)
| Title |
|---|
| 张淑娥等: "《汽轮机蒸汽湿度测量系统的频率跟踪设计》", 《国外电子元器件》, no. 2, 31 December 2008 (2008-12-31), pages 3 - 5 * |
| 赵君超: "《微波谐振腔测湿系统的研究》", 《中国优秀硕士学位论文全文数据库》, 15 May 2007 (2007-05-15) * |
Cited By (14)
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| CN105021885A (en) * | 2015-05-15 | 2015-11-04 | 天津大学 | Frequency tracking measurement device for microwave resonant cavity |
| CN105067654A (en) * | 2015-09-11 | 2015-11-18 | 天津大学 | Single-mode resonant cavity sensor-based solution concentration measurement method |
| CN107014419A (en) * | 2017-03-23 | 2017-08-04 | 西安交通大学 | Quartz based on FPGA+SOPC shakes beam resonant transducer test system |
| CN107014419B (en) * | 2017-03-23 | 2020-03-31 | 西安交通大学 | Quartz vibrating beam resonant sensor test system based on FPGA + SOPC |
| CN108562798A (en) * | 2018-07-02 | 2018-09-21 | 中国科学院东北地理与农业生态研究所 | A method of measuring lossy material dielectric constant |
| CN109374691B (en) * | 2018-10-19 | 2020-10-30 | 沈阳师范大学 | Device and method for measuring dielectric constant change rule of graphene solution by microwave |
| CN109374691A (en) * | 2018-10-19 | 2019-02-22 | 沈阳师范大学 | The device and method of microwave measurement graphite alkenes Dielectric constant changing rule |
| CN111610385A (en) * | 2019-02-25 | 2020-09-01 | 川升股份有限公司 | Electrical parameter measuring system |
| CN111610385B (en) * | 2019-02-25 | 2023-03-14 | 川升股份有限公司 | Electrical parameter measuring system |
| CN115220370A (en) * | 2021-04-16 | 2022-10-21 | 天津大学 | FPGA-based solution concentration real-time monitoring system |
| CN113418939A (en) * | 2021-07-01 | 2021-09-21 | 北京普瑞迈科技术有限公司 | Microwave resonance structure and system for measuring concentration of solutions such as rubber latex |
| CN113465633A (en) * | 2021-08-09 | 2021-10-01 | 东南大学 | Microwave resonant sensor for software intelligent detection and frequency shift detection method thereof |
| CN113465633B (en) * | 2021-08-09 | 2023-01-03 | 东南大学 | Microwave resonant sensor for software intelligent detection and frequency shift detection method thereof |
| CN114152634A (en) * | 2021-10-25 | 2022-03-08 | 广西大学 | Novel intelligent measurement system and method for brix |
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Application publication date: 20121205 |