CN101975722B - Differential type fiber liquid density measuring device and method - Google Patents
Differential type fiber liquid density measuring device and method Download PDFInfo
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- CN101975722B CN101975722B CN2010102977450A CN201010297745A CN101975722B CN 101975722 B CN101975722 B CN 101975722B CN 2010102977450 A CN2010102977450 A CN 2010102977450A CN 201010297745 A CN201010297745 A CN 201010297745A CN 101975722 B CN101975722 B CN 101975722B
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Abstract
The invention provides differential type fiber liquid density measuring device and method. The device comprises a circuit unit, an LED point light source, a launching fiber, two receiving fibers and a fiber end light field and light intensity detecting unit consisting of photodiode detectors, wherein the LED point light source is arranged right above the launching fiber; modulated light emitted by the LED point light source is coupled to the launching fiber; the launching fiber is half immersed into liquid to be measured, and the lower end of the launching fiber is respectively connected withtwo receiving fibers of the photodiode detectors which are in parallel put below the launching fiber; one receiving fiber is coaxially arranged with the launching fiber; and output signals of the twophotodiode detectors are transmitted to the circuit unit. The invention relates to a liquid density on-line measuring scheme and has the characteristics of high sensitivity, good real time, strong capacity of resisting electromagnetic interference, convenient compensation, high reliability, small volume, convenient measurement, and the like.
Description
Technical field
What the present invention relates to is a kind of liquid density measurement device, the present invention also relates to a kind of liquid density measurement method.
Background technology
All need measure at industrial circles such as oil, chemical industry, metallurgy, food, medicine fluid density.The measurement of fluid density can be divided into by principle: optical profile type, capacitance sensing type, semiconductor-type, biological formula etc.Wherein the optical profile type measuring method has the incomparable advantage of many other modes, as highly sensitive, response speed is fast, antijamming capability is strong etc., but it does not have the on-line measurement function usually, can't realize digitizing yet.In traditional fluid density measuring method, less relatively like the Abbe refractometer measurement range, and can not realize online and automatic the measurement; And survey concentration with polarimeter, and only be applicable to the liquid of optical activity, also can't realize online and automatic the measurement, owing to will judge whether the brightness of three fens visual fields is identical, be easy to generate bigger error by human eye.
Summary of the invention
The object of the present invention is to provide a kind of highly sensitive, real-time good, anti-electromagnetic interference capability is strong, be convenient to compensation, reliability is high, volume is little, measures differential type fiber liquid density measuring equipment easily.The present invention also aims to provide a kind of measuring method of utilizing differential type fiber liquid density measuring equipment.
The objective of the invention is to realize like this:
Differential type fiber liquid density measuring equipment of the present invention comprises circuit unit, LED pointolite, the optical fiber end light field light intensity probe unit that launching fiber, two root receiving fibers and photodiode detector are formed; The LED pointolite is positioned at directly over the launching fiber; The light modulated that the LED pointolite sends is coupled to launching fiber; Launching fiber partly is dipped in the testing liquid; Two root receiving fibers that the lower end is connected with photodiode detector respectively are placed in parallel in the launching fiber below, and the one of which root receiving fiber lays with launching fiber is coaxial, and the output signal of two photodiode detectors is given circuit unit.
Said circuit unit comprises LED pointolite driving circuit, harmonic wave modulation circuit, data acquisition and demodulator circuit and control and data processing unit.
Can also comprise the fluid temperature measuring sonde, the fluid temperature measuring sonde is connected with circuit unit.
Utilize the measuring method of differential type fiber liquid density measuring equipment to be: adopt the differential type fiber liquid density measuring equipment of the optical fiber end light field light intensity probe unit that comprises circuit unit, LED pointolite, launching fiber, two root receiving fibers and a photodiode detector composition, circuit unit comprises LED pointolite driving circuit, harmonic wave modulation circuit, data acquisition and demodulator circuit and control and data processing unit; The LED pointolite is positioned at directly over the launching fiber; Launching fiber partly is dipped in the testing liquid; The two root receiving fibers composition optical fiber end light field light intensity probe unit that the lower end is connected with photodiode detector respectively is placed in parallel in the launching fiber below; The one of which root receiving fiber lays with launching fiber is coaxial, and the output signal of two photodiode detectors is given circuit unit; LED pointolite driving circuit drives LED pointolite, LED pointolite and launching fiber coupling make launching fiber end distribution of light intensity change by modulating mode, and the angle of divergence and the light distribution of launching fiber end light field are relevant with fluid density; The emergent light that receives optical fiber is given circuit unit through optical fiber end light field light intensity probe unit; After opto-electronic conversion, amplification, demodulation process; Obtain two signals that not influenced by the small drift of drive current direct current; These two signals are done difference processing, and measure current fluid temperature, promptly draw the fluid density information under the Current Temperatures.
The drive current of LED is sent into led light source after the harmonic wave modulation; The launching fiber that couples light to end immersion fluid to be measured that is sent, the angle of divergence of this optical fiber end light field is relevant with liquid refractivity, and liquid refractivity is corresponding with fluid density; So light distribution will be relevant with fluid density; The angle of divergence is decided rate by the refraction of light and is confirmed, radially light distribution is near Gaussian distribution in launching fiber end light field, and two parallel reception optical fiber are opposite in the luminous fine end light field with launching fiber mutually; And wherein an optical fiber lays with launching fiber is coaxial; Then two receive the light intensity signal that optical fiber can receive launching fiber modulated terminal light field, again after photoelectric commutator and signal demodulation, can be from these two light intensity signals the density information of extracting liq under Current Temperatures.
Differential type fiber liquid density measuring equipment of the present invention and measuring method are the online measurement scheme of a kind of fluid density.This scheme is utilized differential type measurement structure and light field harmonic wave modulation technique, and the relation of light distribution of optical fiber end light field and fluid density realizes the measurement to fluid density.Take the differential type measuring method can eliminate the influence of light source fluctuation and fiber axis effectively to micro-displacement.The software section of follow-up signal processing section can be realized the measurement of liquid refractivity through suitable change.That the present invention has is highly sensitive, real-time good, anti-electromagnetic interference capability is strong, be convenient to compensation, reliability is high, volume is little, measures characteristics such as convenient.
Description of drawings
Fig. 1 is the structural representation of differential type fiber liquid density measuring equipment of the present invention;
Fig. 2 is a radially light intensity synoptic diagram of launching fiber end light field of the present invention.
Embodiment
For example the present invention is done description in more detail below in conjunction with accompanying drawing:
In conjunction with Fig. 1, differential type fiber liquid density measuring equipment comprises red-light LED pointolite 4 and circuit unit 3 (comprising: LED pointolite driving circuit, harmonic wave modulation circuit, data acquisition and demodulator circuit, control and data processing unit etc.), launching fiber 5, main reception optical fiber 6, assists reception optical fiber 7, photodiode detector 8, photodiode detector 9, launching fiber end light field 10, fluid temperature probe 11.When measuring fluid density; Launching fiber 5 half is dipped in the liquid; LED pointolite 4 is positioned at launching fiber 5 dead aheads, has modulated the current drives red-light LED pointolite 4 of harmonic signal, and the distribution of light intensity of LED pointolite is changed by modulating mode; The light modulated that the LED pointolite sends is coupled to launching fiber 5, so the angle of divergence of this optical fiber end light field and light distribution will be relevant with fluid density.Two root receiving fibers 6 and 7 are placed in parallel in launching fiber 5 the place aheads, and wherein receive optical fiber 6 and launching fiber 5 coaxial laying, and the output signal of photoelectric commutator 8,9 is given circuit unit 3; After amplification, analog to digital conversion and demodulation, its difference has promptly been carried fluid density information, after follow-up signal is handled and demarcated; Can obtain the fluid density value; In addition, through regulating the position relation between 6 and 7, can obtain maximum measurement dynamic range.The software section of follow-up signal processing section can be realized the measurement of liquid refractivity through suitable change.In Fig. 1,1 is the testing liquid container, and 2 is testing liquid.
Claims (4)
1. differential type fiber liquid density measuring equipment, the optical fiber end light field light intensity probe unit that comprises circuit unit, LED pointolite, launching fiber, forms by two root receiving fibers and photodiode detector; It is characterized in that: the LED pointolite is positioned at directly over the launching fiber; The light modulated that the LED pointolite sends is coupled to launching fiber; Launching fiber partly is dipped in the testing liquid; Two root receiving fibers that the lower end is connected with photodiode detector respectively are placed in parallel in the launching fiber below, and the one of which root receiving fiber lays with launching fiber is coaxial, and the output signal of two photodiode detectors is given circuit unit.
2. differential type fiber liquid density measuring equipment according to claim 1 is characterized in that: said circuit unit comprises LED pointolite driving circuit, harmonic wave modulation circuit, data acquisition and demodulator circuit and control and data processing unit.
3. differential type fiber liquid density measuring equipment according to claim 1 and 2 is characterized in that: also comprise the fluid temperature measuring sonde, the fluid temperature measuring sonde is connected with circuit unit.
4. measuring method of utilizing differential type fiber liquid density measuring equipment; It is characterized in that: adopt the differential type fiber liquid density measuring equipment of the optical fiber end light field light intensity probe unit comprise circuit unit, LED pointolite, launching fiber, to be made up of two root receiving fibers and photodiode detector, circuit unit comprises LED pointolite driving circuit, harmonic wave modulation circuit, data acquisition and demodulator circuit and control and data processing unit; The LED pointolite is positioned at directly over the launching fiber; Launching fiber partly is dipped in the testing liquid; The optical fiber end light field light intensity probe unit that the lower end is connected with the two root receiving fibers composition of photodiode detector respectively is placed in parallel in the launching fiber below; The one of which root receiving fiber lays with launching fiber is coaxial, and the output signal of two photodiode detectors is given circuit unit; LED pointolite driving circuit drives LED pointolite, LED pointolite and launching fiber coupling make launching fiber end distribution of light intensity change by modulating mode, and the angle of divergence and the light distribution of launching fiber end light field are relevant with fluid density; The emergent light that receives optical fiber is given circuit unit through optical fiber end light field light intensity probe unit; After opto-electronic conversion, amplification, demodulation process; Obtain two signals that not influenced by the small drift of drive current direct current; These two signals are done difference processing, and measure current fluid temperature, promptly draw the fluid density information under the Current Temperatures.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102977450A CN101975722B (en) | 2010-09-30 | 2010-09-30 | Differential type fiber liquid density measuring device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102977450A CN101975722B (en) | 2010-09-30 | 2010-09-30 | Differential type fiber liquid density measuring device and method |
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| Publication Number | Publication Date |
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| CN101975722A CN101975722A (en) | 2011-02-16 |
| CN101975722B true CN101975722B (en) | 2012-02-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2010102977450A Expired - Fee Related CN101975722B (en) | 2010-09-30 | 2010-09-30 | Differential type fiber liquid density measuring device and method |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103674775B (en) * | 2013-12-17 | 2015-12-02 | 哈尔滨工程大学 | A kind of differential type liquid density measurement device based on total reflection principle |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101629890A (en) * | 2009-08-17 | 2010-01-20 | 昆明理工大学 | Float type fiber grating liquid densimeter |
| CN101793659A (en) * | 2010-03-12 | 2010-08-04 | 上海华魏光纤传感技术有限公司 | Distributed optical fiber equal salt deposit density sensor and sensing method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01197634A (en) * | 1988-02-03 | 1989-08-09 | Fujikura Ltd | Liquid refractometer and liquid concentration meter using same |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101629890A (en) * | 2009-08-17 | 2010-01-20 | 昆明理工大学 | Float type fiber grating liquid densimeter |
| CN101793659A (en) * | 2010-03-12 | 2010-08-04 | 上海华魏光纤传感技术有限公司 | Distributed optical fiber equal salt deposit density sensor and sensing method thereof |
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| CN101975722A (en) | 2011-02-16 |
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Granted publication date: 20120201 Termination date: 20170930 |