CN207147589U - The continuous liquid level sensing device of hollow optic fibre based on OFDR - Google Patents
The continuous liquid level sensing device of hollow optic fibre based on OFDR Download PDFInfo
- Publication number
- CN207147589U CN207147589U CN201720987121.9U CN201720987121U CN207147589U CN 207147589 U CN207147589 U CN 207147589U CN 201720987121 U CN201720987121 U CN 201720987121U CN 207147589 U CN207147589 U CN 207147589U
- Authority
- CN
- China
- Prior art keywords
- optic fibre
- hollow
- fiber
- optical fiber
- liquid level
- 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.)
- Active
Links
- 239000000835 fiber Substances 0.000 title claims abstract description 156
- 239000007788 liquid Substances 0.000 title claims abstract description 68
- 238000002168 optical frequency-domain reflectometry Methods 0.000 title claims abstract description 23
- 239000013307 optical fiber Substances 0.000 claims abstract description 47
- 230000035559 beat frequency Effects 0.000 claims abstract description 19
- 238000010408 sweeping Methods 0.000 claims abstract description 5
- 230000008859 change Effects 0.000 claims description 16
- 238000012360 testing method Methods 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 5
- 238000004891 communication Methods 0.000 claims description 2
- 238000004458 analytical method Methods 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 description 14
- 238000005259 measurement Methods 0.000 description 14
- 238000012544 monitoring process Methods 0.000 description 9
- 238000001228 spectrum Methods 0.000 description 9
- 230000003287 optical effect Effects 0.000 description 7
- 238000012545 processing Methods 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 238000004422 calculation algorithm Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 239000002360 explosive Substances 0.000 description 3
- 238000009499 grossing Methods 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 241000931526 Acer campestre Species 0.000 description 2
- 241000208340 Araliaceae Species 0.000 description 2
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 2
- 235000003140 Panax quinquefolius Nutrition 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 235000008434 ginseng Nutrition 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000012792 core layer Substances 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000002405 diagnostic procedure Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000004038 photonic crystal Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Landscapes
- Light Guides In General And Applications Therefor (AREA)
Abstract
The utility model discloses a kind of continuous liquid level sensing device of the hollow optic fibre based on OFDR, including linear frequency sweep laser, fiber optic splitter, optical fiber circulator, hollow optic fibre, fiber coupler, photodetector, data collecting card and computer；Sweeping laser is divided into two-way by fiber optic splitter, is all the way flashlight, another way is reference light；Flashlight enters the optical fiber circulator, and reference light enters the fiber coupler；Flashlight enters the hollow optic fibre by single-mode fiber；Backreflected signals light in single-mode fiber is imported the fiber coupler by optical fiber circulator, and beat frequency interference occurs at the fiber coupler with reference light；The beat frequency interference signal is converted into electric signal by photodetector；Beat frequency interference signal in data collecting card collection electric signal；Computer controls the linear frequency sweep laser and the data collecting card, also carries out Treatment Analysis to beat frequency interference signal, and send data to slave computer.
Description
Technical field
Technical field of optical fiber sensing is the utility model is related to, more specifically, is related to one kind and is based on OFDR (probe beam deflations
Technology) the continuous liquid level sensing device of hollow optic fibre.
Background technology
The utility model is mainly used in the continuous liquid level in the inflammable and explosive application such as petrochemical industry and aircraft oil storage tank
Measurement.Conditional electronic or mechanical liquid level sensor in inflammable and explosive environment level monitoring be limited, fibre optic liquid level sensor
Advantage with burn-proof and explosion prevention is more suitable for the level monitorings such as petrochemical industry and aircraft fuel oil.
At present, the continuous liquid level sensor of optical fiber mainly has four classes：Fibre optic liquid level sensor based on full optical fiber interferometer, should
Sensor is that sensing arrangement internal intervention is composed to realize level gauging, measurement essence when submerging sensing arrangement by demodulating testing liquid
Degree is high, but repeatability is not high, and measurement range is extremely limited, generally only several centimetres；Based on sensing arrangements such as fiber gratings
Wavelength mediation practices, grating is fixed on such as mechanical floats in structure, liquid level rise causes mechanical floats to deform upon
And acting on fiber grating so that the wavelength of fiber grating reflection changes, so as to realize level monitoring to Wavelength demodulation,
The outside mechanical structure of this method needs, measurement result reliability be not high；Based on reflective or transmission-type intensity demodulation optical fiber
Liquid level sensor, by making some special structures so that testing liquid acts on reflected light or transmission when on this structure
Light changes, so as to realize level monitoring.This method precision is not high, and range is limited, and sensing arrangement is unstable to cause measurement to be tied
Fruit is inaccurate；Detect the fibre optic liquid level sensor of backreflected signals, such as the optical fiber based on OTDR (optical time domain reflection technology)
Liquid level sensor.Because OTDR can be to be positioned along optical fiber and loss measurement, therefore when testing liquid is acted on optical fiber
When can change the opening position light backreflected signals, level monitoring is realized by the detection to reflected signal, this method
Measurement range is big, but precision is very low, generally other in meter level.
Therefore, there is an urgent need to a kind of range is big, precision is high, stability in the application such as petrochemical industry and aircraft fuel reserve tank
The good continuous liquid level sensing device of optical fiber.
Utility model content
For the disadvantages described above or Improvement requirement of prior art, the utility model provides a kind of hollow light based on OFDR
Fine liquid level sensor.The utility model uses hollow optic fibre as sensing head using OFDR technologies, using OFDR technologies to hollow
Retroreflection optical signal along optical fiber is detected, so as to realize continuous level monitoring.The sensor measurement range is big, precision
It is high, reproducible, reliability is high.Monitoring especially suitable for petrochemical industry and aircraft fuel reserve tank liquid level.
In order to solve the above-mentioned technical problem, technical scheme is used by the utility model：
A kind of continuous liquid level sensing device of the hollow optic fibre based on OFDR, including linear frequency sweep laser, optical fiber point are provided
Beam device, optical fiber circulator, hollow optic fibre, fiber coupler, photodetector, data collecting card and computer；Wherein：
The sweeping laser that the linear frequency sweep laser exports is divided into two-way by the fiber optic splitter, is all the way signal
Light, another way are reference light；Flashlight enters the optical fiber circulator, and reference light enters the fiber coupler；
The hollow optic fibre is connected by single-mode fiber with the optical fiber circulator, and flashlight is entered by single-mode fiber should
Hollow optic fibre, the hollow optic fibre are placed in the container for holding solution to be measured, perceive liquid level change；Flashlight is in the hollow light
Backscatter signal is produced on fibre, and single-mode fiber is back to along road；
Optical fiber circulator, the backreflected signals light in single-mode fiber is imported into the fiber coupler, retroreflection letter
With reference light beat frequency interference, generation beat frequency interference signal occur at the fiber coupler for number light；
The photodetector, it is connected with the circulator, the beat frequency interference signal is converted into electric signal；
The data collecting card gathers the beat frequency interference signal in electric signal by multichannel simultaneously；
The computer enters row data communication, and sends data with the linear frequency sweep laser, the data collecting card
To slave computer.
Connect above-mentioned technical proposal, the scanning range of the linear frequency sweep laser is 1520nm-1630nm, sweep velocity
2nm/s-2000nm/s。
Above-mentioned technical proposal is connect, the sweeping laser that the linear frequency sweep laser exports is divided into by the fiber optic splitter
50：50 two-way.
Above-mentioned technical proposal is connect, the hollow optic fibre includes hollow core, covering and overlay.
Above-mentioned technical proposal is connect, the hollow optic fibre is multimode step change type quartz glass optical fiber.
The continuous continuous liquid level sensing device of liquid level sensing device is beneficial possessed by the utility model compared with prior art
Effect is：The utility model proposes a kind of continuous liquid level sensing device of the hollow optic fibre based on OFDR technologies, using special sky
Heart optical fiber is as sensing head.Using the loss characteristic of hollow optic fibre, continuous level gauging is realized.The utility model continuously measures model
Enclose more than 100 meters, precision is better than 0.1mm, fast response time.The continuous liquid level of high accuracy in the range of 100 meters can be achieved to measure in real time.
Especially suitable for the continuous liquid level high-acruracy survey in the inflammable and explosive application such as petrochemical industry and aircraft oil storage tank.
Brief description of the drawings
Specific embodiment of the present utility model is described in further detail below by accompanying drawing.
Fig. 1 is continuous level gauging structure principle chart of the present utility model；
Fig. 2 is hollow optic fibre structure chart；
Fig. 3 is liquid level schematic diagram when liquid level to be measured submerges one section of hollow optic fibre；
Fig. 4 is the continuous level gauging criterion schematic diagram of hollow optic fibre；
Fig. 5 is that hollow optic fibre submerges the measurement result spectrogram after one section；
Fig. 6 is spectrogram of the measurement result after smoothing processing.
In Fig. 1：1 it is linear frequency sweep laser, 2 is fiber optic splitter (50：50) 3 it is, optical fiber circulator, 4 is single-mode optics
It is fine, 5 be hollow optic fibre, 6 be fiber coupler (1x2), 7 be photodetector, 8 be data collecting card, 9 be computer, 10 be
Liquid level.
Embodiment
The utility model will be further described for example below combination accompanying drawing.
The continuous liquid level sensing device of hollow optic fibre based on OFDR, including linear frequency sweep laser 1, fiber optic splitter (50：
50) 2, optical fiber circulator 3, single-mode fiber 4, hollow optic fibre 5, fiber coupler (1x2) 6, photodetector 7, data collecting card 8
With computer 9.
The linear scan laser 1 and fiber optic splitter (50：50) 2 inputs connect, fiber optic splitter (50：50) it is defeated
Go out a port of the end respectively with a ports of optical fiber circulator 3 and fiber coupler (1x2) 6 to be connected.The b mouths of optical fiber circulator 3 with
Single-mode fiber is connected, and c mouths are connected with the b mouths of fiber coupler (1x2) 6.Single-mode fiber 4 is connected with hollow optic fibre 5.Hollow optic fibre
5 are placed in the container for holding solution to be measured, perceive liquid level change.Except hollow optic fibre, a variety of sensor fibres are all in theory
It is possible, such as photonic crystal fiber.
Linear scan laser 1 sends the laser of optical maser wavelength periodicity linear change, and laser enters fiber optic splitter
(50：50) 2 points are two-way light.Light is flashlight all the way, is all the way reference light.Reference light is directly coupled into fiber coupler 6
In an input.Flashlight enters optical fiber circulator 3 and is transferred to single-mode fiber 4, then hollow by the entrance of single-mode fiber 4
Optical fiber 5, flashlight caused backscatter signal on the hollow optic fibre 5 are back to single-mode fiber 4 along road.
Rear orientation light on single-mode fiber 4 returns to optical fiber circulator 3 along road and enters light by the c mouths outgoing of circulator
Another input of fine coupler 6.Two-way light interferes at fiber coupler 6.Due to the light of two-way light return signal
Cheng Butong, time delay is introduced, then contain beat signal in interference signal.After photodetector 7, interference light signal is converted to electricity
Signal, is gathered by data collecting card 8 and is done Fast Fourier Transform (FFT) by computer 9 and obtain the spectrum information of beat signal.
Computer 9 can send data to the warning circuit down；The warning circuit issues according to the computer 9 of reception
Data, control indicator lamp and alarm.
The scanning range of linear frequency sweep laser 1 is 1520nm-1630nm, sweep velocity 2nm/s-100nm/s.
The light velocity and laser sweep speed determine that the big I of beat signal frequency measured is mapped as physical distance, and claps
Frequency signal intensity is proportional to the intensity of reflected signal.
It is mainly backward Rayleigh scattering using the rear orientation light along the hollow optic fibre 5 of OFDR technology for detection.It is backward auspicious
Profit scattering is directly proportional to incident intensity.Because the light of hollow optic fibre 5 can enter inside of optical fibre hollow area, into hollow area
Light be a kind of fast subwave field, the most of luminous power for being coupled into hollow optic fibre in other words is to be wasted in the fast subwave of guiding
.And the relative index of refraction change between hollow optic fibre fibre core and covering result in the change of fast subwave field in covering.Work as fibre core
When refringence between hollow area is reduced, the fast subwave field of hollow area can add, so that fiber transmission attenuation increases.
Generally, loss factor is less than loss factor when transmitting in a liquid when hollow optic fibre 5 transmits in atmosphere.
OFDR technologies can measure and analyze to the loss characteristic along hollow optic fibre, when the part of hollow optic fibre 5
When a part is located in testing liquid in air, in the backscatter signal along the hollow optic fibre 5 of measurement, air and liquid
The beat signal amplitude of the boundary of body has drop, and the slope on both sides is different.The slope of beat signal is exhausted at air
Small to being worth, the slope absolute value of beat signal is big at liquid.
Based on this basis for estimation, respective algorithms processing is carried out to the data of collection, testing liquid can be deduced
Liquid level is at the frequency spectrum boundary position of hollow optic fibre beat signal.
Operation principle of the present utility model is to be based on OFDR technologies, and analyzing and processing is carried out to beat frequency interference information and is realized continuously
Liquid level high-acruracy survey.Hollow optic fibre is placed on as sensing head and contained at testing liquid, and is fixed in container.Prepare liquid
Body rises one section of submergence hollow optic fibre, and surrounding environment residing for the hollow optic fibre being submerged is testing liquid, and the top of liquid level is
Air.All backscatter signals along hollow optic fibre are handled, phase is carried out after measuring the loss characteristic of hollow optic fibre
Close algorithm demodulation and calculate liquid level present position to be measured.
It is of the present utility model to be referred to based on OFDR technologies：Linear scan laser 1 sends the periodically linear change of optical maser wavelength
The laser of change, laser enter fiber optic splitter (50：50) 2 points are two-way light.Light is flashlight all the way, is all the way reference light.Ginseng
Examine a mouths that light is directly coupled into fiber coupler (1x2) 6.Flashlight enters a mouths of optical fiber circulator 3 and is transferred to list
Hollow optic fibre is entered back into after mode fiber 4.In hollow optic fibre back scattering occurs for flashlight, and rear orientation light returns to optical fiber along road
Circulator 3 and the b mouths for entering fiber coupler (1x2) 6 by the c mouths outgoing of optical fiber circulator 3.Two-way light is in fiber coupler
Interfered at (1x2) 6.Because reference light is different with the light path of rear orientation light, time delay is introduced, then is contained in interference signal
Beat signal.After photodetector 7, interference light signal is converted to electric signal, is gathered by data collecting card 8, and in computer 9
In do Fast Fourier Transform (FFT) and obtain the spectrum information of beat signal.The spectrogram of measurement includes the back scattering of single-mode fiber
The part converted with the interference information of reference light.But the optical fiber for being actually used for sensing is that section of optical fiber of hollow optic fibre, can
To set the spectrum information for filtering out this section single-mould fiber (to remove an above segment information can, because distance is 0 position
It is that oneself is chosen, all measurement distances are all with the relative distance of 0 reference point).
Spatial resolution can be achieved in tens micron dimensions in OFDR technologies in 100 meters of Distance-sensings at present, therefore this
The precision of the continuous level monitoring of utility model is very high.
Generally, the big I of beat signal frequency that optical frequency domain reflection technology measures is mapped as physical distance, short distance
Spatial resolution, while can also long distance monitoring in tens micron dimensions.The beat signal that optical frequency domain reflection technology measures is strong
Degree is then proportional to the intensity of reflected signal.
Hollow optic fibre 5 is made up of hollow core, covering and overlay, and the symmetrical cylinder of a multilayer dielectric structure
Body, (such as Fig. 2) that only its fibre core is internally hollow.Cladding outer diameter 125um, cladding thickness 75um can be selected in hollow optic fibre,
Core diameter 50um, wherein internal diameter 20um.Hollow optic fibre covering and core structure are all made of silica.Coating outside covering
Layer material is made up of acrylate, silicon rubber and nylon etc..
Hollow optic fibre has the characteristic of universal optical fibre, thus the elementary principle and theory of optical fiber is also applied for hollow optic fibre.
From ray theory, the propagation of light in a fiber mainly propagation of the foundation total reflection principle but light in hollow optic fibre is also
The interface formed by hollow position fibre core and air is influenceed have certain particularity.
The difference of hollow interior injection material, loss characteristic is also different when light is propagated in a fiber.Especially refractive index is high
Light intensity change is most notable caused by liquid, and this light occurs mainly due to when refractive index of the liquid refractivity close to fibre core
Line is refracted to the phenomenon of liquid by fibre core, has the property of leak type fiber waveguide.
The hollow optic fibre of the utility model embodiment is a kind of multimode step change type quartz glass optical fiber of high-purity, loss
It is low, it is about 0.5d B/Km in the minimum loss of 1550nm wave bands.What fibre core was internally hollow, its inner surface without covering and
Overlay.When light is propagated in fiber core layer, light can enter inside of optical fibre hollow area, and the light into hollow area is one kind
Fast subwave field, it is existed only in one layer of region thick from the λ of hollow optic fibre inwall about 0.7, and the maximum of its field strength is only core
10% or so of guided wave field maximum in layer.Therefore propagation loss of the light in hollow optic fibre mostlys come from the fast subwave of guiding
.And the relative index of refraction change between hollow optic fibre fibre core and covering result in the change of fast subwave field in covering, work as fibre core
When refringence between hollow area is reduced, the fast subwave field of hollow area can add, so that fiber transmission attenuation increases.
By in the vertical fixed placement testing liquid of hollow optic fibre.Using above-mentioned OFDR technologies, to hollow optic fibre back scattering
Signal is acquired Treatment Analysis with beat signal caused by reference light beat frequency interference.
As shown in figure 3, inside one section that hollow optic fibre is submerged in testing liquid uphill process and entrance hollow optic fibre
Hollow hole.Now, it is filled with the liquid highly consistent with extraneous testing liquid in hollow optic fibre inner air hole.
As shown in figure 4, when hollow optic fibre is in air, the hollow area of hollow optic fibre is air, and refractive index is equal to
1, the refringence between fibre core and hollow area is larger, and the fast subwave field of hollow area is smaller；When hollow optic fibre is in liquid
When middle, the hollow area of hollow optic fibre is testing liquid, refractive index n>1, the now refractive index between fibre core and hollow area
Difference is smaller, and the fast subwave field of hollow area is larger, positioned at the rapid increase of hollow optic fibre loss of liquid portion.
Therefore, when a part for testing liquid submergence hollow optic fibre, hollow optic fibre loss size at liquid level present position
Separation.Liquid level present position to be measured can be calculated by calculating the separation position by respective algorithms.
The beat frequency interference signal demodulating method of the continuous liquid level sensing device of hollow optic fibre of the utility model embodiment is main
It is that Fourier transformation processing is carried out to the interference signal of collection, finds loss separation.
Its specific algorithm includes several steps,
The first step, based on OFDR principles, using optical heterodyne detection technique, to backscatter signal along sensor fibre and ginseng
The interference signal after arm generation beat frequency interference is examined to be acquired.
Second step, the beat signal gathered using computer to the first step are carried out non-uniform Fast Fourier and convert to obtain sky
Beat frequency frequency spectrum corresponding to along heart optical fiber.It is illustrated in figure 5 beat frequency frequency spectrum corresponding to along hollow optic fibre.
3rd step, drop point average treatment is carried out to beat frequency frequency spectrum, it is therefore an objective to reduce whole spectrum number strong point and accelerate fortune
Calculate speed,
4th step, smoothing processing.Purpose is so that whole spectrogram is more smooth, is easy to find loss characteristic separation,
That is the corner position of spectrogram.It is illustrated in figure 6 spectrogram of the measurement result after smoothing processing.
5th step, the flex point approximate location for calculating spectrogram.Main Basiss slope absolute value diagnostic method realizes, separation
The slope absolute value of the loss attenuation curve on position both sides is different.According to this distinguishing rule, interference spectrum Fourier is become
Data point carries out slope calculating after change.The point that slope is chosen in calculating is two data points at a distance of fixed intervals, from starting number
Strong point starts node-by-node algorithm successively.The setting of gap size depends on data point size synthetic determination.All data point slope meters
After the completion of calculation, derivation is carried out to slope, derivative absolute value is found out and arranges from big to small, find out the horizontal seat corresponding to derivative maximum
Cursor position.The abscissa positions are the approximate location of separation.
6th step, the corner position of accurate calculation spectrogram.Abscissa corresponding to the approximate location found out in the 4th step,
To from left to right difference walk fixed intervals data point, (setting of gap size depends on data point size synthetic determination.) passing through
After data after 4th step remove the substantially data point of corner position or so, piecewise fitting is carried out, fit approach is first-order linear
Fitting.The position of intersecting point for obtaining the straight line after two fittings is the elaborate position of flex point.
7th step, this position and liquid level zero elevation reference position subtracted each other, obtain the relative value of liquid level.
So far height where having found out liquid level to be measured.It is to be noted that：Above-mentioned steps can single treatment in a computer
Complete.
As it will be easily appreciated by one skilled in the art that drawings and Examples described herein are only illustrating the utility model
Technical scheme rather than its limitations, it is all do not depart from the utility model spirit and principle within made any modification, etc.
With replacement and improvement etc., it all should cover among the claimed technical scheme scope of the utility model.
Claims (6)
1. the continuous liquid level sensing device of a kind of hollow optic fibre based on OFDR, it is characterised in that including linear frequency sweep laser, light
Fine beam splitter, optical fiber circulator, hollow optic fibre, fiber coupler, photodetector, data collecting card and computer；Wherein：
The sweeping laser that the linear frequency sweep laser exports is divided into two-way by the fiber optic splitter, is all the way flashlight, separately
It is reference light all the way；Flashlight enters the optical fiber circulator, and reference light enters the fiber coupler；
The hollow optic fibre is connected by single-mode fiber with the optical fiber circulator, and flashlight is hollow into this by single-mode fiber
Optical fiber, the hollow optic fibre are placed in the container for holding solution to be measured, perceive liquid level change；Flashlight is on the hollow optic fibre
Backscatter signal is produced, and single-mode fiber is back to along road；
Optical fiber circulator, the backreflected signals light in single-mode fiber is imported into the fiber coupler, backreflected signals light
Beat frequency interference occurs at the fiber coupler with reference light, produces beat frequency interference signal；
The photodetector, it is connected with the circulator, the beat frequency interference signal is converted into electric signal；
The data collecting card gathers the beat frequency interference signal in electric signal by multichannel simultaneously；
The computer enters row data communication, and sent data to down with the linear frequency sweep laser, the data collecting card
Position machine.
2. the continuous liquid level sensing device of hollow optic fibre as claimed in claim 1 based on OFDR, it is characterised in that described linear
The scanning range of frequency swept laser is 1520nm-1630nm, sweep velocity 2nm/s-100nm/s.
3. the continuous liquid level sensing device of hollow optic fibre as claimed in claim 1 based on OFDR, it is characterised in that the optical fiber
The sweeping laser that the linear frequency sweep laser exports is divided into 50 by beam splitter：50 two-way.
4. the continuous liquid level sensing device of hollow optic fibre as claimed in claim 1 based on OFDR, it is characterised in that described hollow
Optical fiber includes hollow core, covering and overlay.
5. the continuous liquid level sensing device of hollow optic fibre as claimed in claim 1 based on OFDR, it is characterised in that described hollow
In the vertical fixed placement testing liquid of optical fiber.
6. the continuous liquid level sensing device of hollow optic fibre as claimed in claim 1 based on OFDR, it is characterised in that described hollow
Optical fiber is multimode step change type quartz glass optical fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720987121.9U CN207147589U (en) | 2017-08-09 | 2017-08-09 | The continuous liquid level sensing device of hollow optic fibre based on OFDR |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720987121.9U CN207147589U (en) | 2017-08-09 | 2017-08-09 | The continuous liquid level sensing device of hollow optic fibre based on OFDR |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207147589U true CN207147589U (en) | 2018-03-27 |
Family
ID=61674614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720987121.9U Active CN207147589U (en) | 2017-08-09 | 2017-08-09 | The continuous liquid level sensing device of hollow optic fibre based on OFDR |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207147589U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108507981A (en) * | 2018-04-11 | 2018-09-07 | 南京大学 | Silica-based waveguides back reflection sensing device based on OFDR and its measurement method |
-
2017
- 2017-08-09 CN CN201720987121.9U patent/CN207147589U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108507981A (en) * | 2018-04-11 | 2018-09-07 | 南京大学 | Silica-based waveguides back reflection sensing device based on OFDR and its measurement method |
| CN108507981B (en) * | 2018-04-11 | 2020-09-22 | 南京大学 | Silicon-based waveguide back reflection sensing device based on OFDR (optical frequency domain reflectometry) and measuring method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yang et al. | A review of recent developed and applications of plastic fiber optic displacement sensors | |
| CN107515033B (en) | Point type liquid level sensor device and its measurement method based on optical frequency domain reflection technology | |
| CN101957227B (en) | Photonic crystal fiber optic liquid level sensor and sensing system formed by same | |
| CN102323239B (en) | Refractive index sensor based on asymmetric double-core optical fiber | |
| CN101718571B (en) | Tilt fiber bragg grating (TFBG) liquid level change measuring instrument | |
| CN109959403B (en) | Multi-parameter large-capacity sensing system | |
| JP2020514724A (en) | Distributed fiber sensor and system using hybrid core optical fiber | |
| CN204228235U (en) | Based on the optical fiber continous way liquid level sensor system of CMFTIR effect | |
| Liehr et al. | Incoherent optical frequency domain reflectometry and distributed strain detection in polymer optical fibers | |
| CN105783866B (en) | A kind of tank gage and sedimentation monitoring system based on low coherence interference technology | |
| US7057735B2 (en) | Method for measuring the optical and physical thickness of optically transparent objects | |
| CN103196520A (en) | Transmission-type optical fiber liquid level sensor with irregular core structure | |
| CN101424562A (en) | Essential explosion-proof liquid level detection device and method | |
| CN107389154A (en) | The continuous liquid level sensing device of hollow optic fibre and measuring method based on OFDR | |
| CN104406573A (en) | Coreless optical fiber-based tilt angle sensor capable of discriminating direction | |
| CN107782696B (en) | Sensing system and method for measuring refractive index of distributed liquid by using tapered optical fiber | |
| US20040036043A1 (en) | Fiber optic level detector | |
| CN207147589U (en) | The continuous liquid level sensing device of hollow optic fibre based on OFDR | |
| EP0079944A1 (en) | Fiber optic interferometer. | |
| US20220390224A1 (en) | Special optical fiber for measuring 3d curved shape, manufacturing method thereof, and system for measuring 3d curved shape by using special optical fiber | |
| CN106289600A (en) | A kind of optical fiber stress sensor part | |
| CN110530466B (en) | Intensity modulation type liquid level sensing detection method based on double-coreless optical fiber cascade connection | |
| JP2008170327A (en) | Refractive index detector and liquid level detector | |
| CN110308115A (en) | A kind of interference-type optical fiber spr sensor | |
| CN108036728A (en) | A kind of phase difference solution mode fiber optics displacement measuring method and instrument |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20210107 Address after: 430074 room 02, 9 / F, building 1, SBI Chuangye street, Dongxin Road, Donghu New Technology Development Zone, Wuhan City, Hubei Province Patentee after: Wuhan Haoheng Technology Co.,Ltd. Address before: No. 999, Gaoxin Avenue, Donghu New Technology Development Zone, Wuhan City, Hubei Province, 430074 Patentee before: WUHAN JUNNO TECHNOLOGY Co.,Ltd. |
|
| TR01 | Transfer of patent right |