CN207036686U - Open long-optical path laser gas on-line monitoring system - Google Patents
Open long-optical path laser gas on-line monitoring system Download PDFInfo
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- CN207036686U CN207036686U CN201720119385.2U CN201720119385U CN207036686U CN 207036686 U CN207036686 U CN 207036686U CN 201720119385 U CN201720119385 U CN 201720119385U CN 207036686 U CN207036686 U CN 207036686U
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Abstract
The utility model provides a kind of open long-optical path laser gas on-line monitoring system, including laser gas analyzer and open long-optical path optical-mechanical system two parts, laser gas analyzer has the wavelength locking function of laser, the demarcation control function of stepper assemblies, the concentration for being finally inversed by laser gas is calculated using fitting algorithm, and realize that concentration is shown, parameter is changed and system calibrating by LCD, and the driving of various lasers can be applied to by changing the parameter of laser driving plate.The utility model has the advantages of can absorbing light path by increasing in a wide range of interior various dusty gas concentration of measurement, improving the detection sensitivity of system.
Description
Technical field
It the utility model is related to environmental gas detection field, and in particular to open long-optical path laser gas on-line monitoring system
System.
Background technology
Optical method is mainly based upon Spectrum Absorption Principle to gas-monitoring, and main method has non-dispersion infrared absorption process, Fu
In leaf infra-red sepectrometry, tunable diode laser absorption spectroscopy method (TDLAS) etc..Non-dispersion infrared absorption process is to utilize gas
When molecule is by infra-red radiation, the infrared light of respective characteristic wavelength will be absorbed, can be true by measuring absorbing wavelength and light absorption value
Determine the concentration of gaseous material, but the stability of a system is poor, and long term drift is big；FTIR spectrum technology can measure more simultaneously
The composition and concentration of kind material, precision is also high, but its is expensive, complex operation；TDLAS technologies are swashed using tunable semiconductor
Light device narrow linewidth and tunable wave length characteristic, realize and the single Absorption Line of gas molecule is monitored on-line, there is gas-selectively to be measured
By force, the advantages that service life is long, demarcation is simple, maintenance is small, and with the commercialization of semiconductor laser, its system cost
It can reduce.
Although external research and application for gas detection technology, the starting of some developed countries is more early, investigated
Many gas detection methods, and there are some to have been applied in practice.It is contemplated that gas concentration detection domestic at present
Instrument market, all it is that some external products are occupied, prices are rather stiff for it, at home researches and develops gas detecting instrument gesture must
OK.
Open long-optical path laser gas on-line monitoring system is namely based on TDLAS technologies, realizes to gas in atmospheric environment
The concentration of body pollution thing is monitored in real time, and laser is by collimation, into gas medium, then by corner reflector, Fresnel Lenses
Reflected, converged, eventually passed through the optical signal after gas medium absorbs and electric signal is converted into by detector 3, can obtain to be measured
The absorption spectrum of some feature of gaseous contaminant infrared band, finally it is finally inversed by the concentration information of gas medium.
Utility model content
The technical problems to be solved in the utility model is to provide a kind of open long-optical path laser gas on-line monitoring
System, tunable diode laser absorption spectroscopy technology and Distributed Feedback Laser wavelength locking technology based on open long-optical path, profit
With the absorption of laser under test gas, by carrying out multi-parameter fitting algorithm to the absorption spectrum of gas molecule, realize to target
Qualitative or quantitative analysis the open long-optical path laser gas on-line monitoring system of gas.
In order to solve the above-mentioned technical problem, the utility model provides open long-optical path laser gas on-line monitoring system,
Laser is provided with including laser gas analyzer and open long-optical path optical-mechanical system two parts, in laser gas analyzer to drive
The circuits such as plate, master board, signal-processing board, detector panel, fiber beam splitting part and LCD industry serial ports screen, wherein laser
Driving plate can select suitable semiconductor laser according to measurement demand, change the parameter value of temperature and current control, ensure to swash
The normal work of light device；The function of master board includes producing laser scans signal, the wavelength locking of laser, outer light path letter
Number detection simultaneously calculates according to fitting algorithm and is finally inversed by the concentration of laser gas, the demarcation control of stepper assemblies, multichannel data
Communication and output etc.；Signal-processing board is amplified filtering process by the outer faint detectable signal of light path is received, with detector panel
Reference path signal forms self-balancing process circuit, effectively reduces the interference component in outer optical path signal, greatly improves noise
Than lifting lowest detection line；Fiber beam splitting part includes fiber optic splitter, collimation lens and fiber coupler, by laser
Laser output is divided into interior light path, reference path and outer light path three parts；There is LCD industry serial ports screen concentration to show, parameter modification
With demarcation control etc. function.Fiber optic collimator coupler, Fresnel Lenses, speculum are provided with open long-optical path optical-mechanical system
Component, stepper assemblies, wedge-shaped window, corner reflector and mechanical adjustment seat, regulation machinery adjustment seat carry out the alignment of light path,
Laser returns to saturating up to Fresnel by collimation direct projection into open long-optical path light path and by corner reflector reflection along original optical path
Mirror, detector is reached after light path convergence, be sent to the retrieving concentration that laser gas is carried out in analyzer；Control stepper assemblies
Rotate speculum so that light path reaches detector by speculum, carries out the coefficient demarcation of system, improves measurement accuracy.
Preferably, in the laser gas analyzer fiber beam splitting part by fiber optic splitter, collimation lens and optical fiber coupling
Clutch is formed, and fiber optic splitter is formed by 5%/95% and 50%/50% two kind, and the emergent light of laser connects through fiber coupler
Enter the input of 5%/95% fiber optic splitter, 95% part is linked into open long light as outer light path with optical fiber in output end
In journey optical-mechanical system, 5% part is linked into the input of 50%/50% fiber optic splitter again, and output end is divided into two and used respectively
In wavelength locking and reference path.
Preferably, signal-processing board uses automatic growth control process circuit, its principle in the laser gas analyzer
After carrying out I/V conversions for outer light path detectable signal, multiplication factor (initial default is 1 grade), root are gated by multiway analog switch
The gear of multiplication factor is automatically selected according to the size of light intensity signal, realize atmospheric environment change it is violent when, outer light path light intensity is not
Can too low or saturation.
Preferably, signal-processing board uses self-balancing process circuit in the laser gas analyzer, and its principle is monolithic
Machine in real time do program control decay, match with outer optical path signal intensity by the outer optical path signal intensity of collection, reference path signal intensity, then
Two paths of signals is subtracted each other and amplifies A times, equivalent to spectral absorption intensity A times is improved, is removed when finally doing retrieving concentration computing
The multiple of spectrum amplification, obtains actual concentration, the principle greatly improves lowest detection line.
Preferably, the signal acquisition control of master board and retrieving concentration are mono- using ARM in the laser gas analyzer
Piece machine realizes that function detects and according to fitting including generation laser scans signal, the wavelength locking of laser, outer optical path signal
Algorithm calculate be finally inversed by the concentration of laser gas, the demarcation control of stepper assemblies, 232 communications, usb communication, network service,
TF card storage, 4~20mA outputs etc..Based on tunable diode laser absorption spectroscopy (TDLAS) technology, open long light path is utilized
Middle under test gas using spectrum simulation algorithm, obtains the extinction of under test gas molecule in the characteristic absorption line of infrared visible waveband
Degree, then Inversion Calculation is carried out, the concentration of under test gas is obtained, is in real time output to concentration results and light intensity parameter by serial ports
In LCD industry serial ports screen and host computer.
Preferably, open long-optical path optical routing fiber optic collimator coupler, phenanthrene in the open long-optical path optical-mechanical system
Nie Er lens, wedge-shaped window, corner reflector etc. are formed, and wherein laser is accessed by laser gas analyzer, is coupled through fiber optic collimator
Laser passes through Fresnel Lenses centre bore after device collimation, and wedge-shaped window is arranged on the afterbody window of cabinet, wedge-shaped window installation
In corner reflector front end, laser returns to Fresnel Lenses along light path and converged, and regulation detector position receives spectral signal.
Preferably, system calibrating is electric by mirror assembly, demarcation gas pond, stepping in the open long-optical path optical-mechanical system
The part such as thermomechanical components is formed, and stepper motor is connected with mirror assembly with connecting rod, when carrying out system calibrating, master board control
Stepper motor processed rotates, and reflection and fiber optic collimator coupler sustained height, laser is successively by fiber optic collimator coupler, reflection
Mirror, demarcation gas pond, reach detector, form demarcation path channels.
The beneficial effect of the utility model compared with prior art：
1) using the outer light path detectable signal of collection of automatic growth control process circuit, ensure that acute in changes in environmental conditions
When strong, outer light path light intensity will not too low or saturation；
2) signal processing circuit based on self-balancing principle is used, greatly improves lowest detection line and the measurement of system
Precision；
3) laser of return converge in detector 3 using Fresnel Lenses in open light path, simplification finishes
Structure, cost is reduced, provided the foundation for instrument miniaturization, facilitation development；
4) outer path channels and system calibrating path channels can be switched by controlling the rotation of stepper motor, complete be
The demarcation of system, concentration factor is changed, improve measuring accuracy；
5) by selecting the laser, Fresnel Lenses and detector 3 of suitable wave band, laser temperature and electric current ginseng are changed
The monitoring of another under test gas can be achieved in number, versatile.
Brief description of the drawings
Fig. 1 is laser gas analyzer theory diagram in the utility model；
Fig. 2 is open long-optical path optical-mechanical system theory diagram in the utility model；
Fig. 3 is the system software main program workflow diagram in the utility model.
Embodiment
Preferred embodiment of the present utility model is described below in conjunction with the accompanying drawings.
As Figure 1-3, as shown in figure 1, being provided with laser driving plate, master board, signal in laser gas analyzer
The circuits such as process plate, detector panel, fiber beam splitting part and LCD industry serial ports screen, wherein laser driving plate can be according to measurement
Demand selects suitable semiconductor laser, changes the parameter value of temperature and current control, ensures the normal work of laser；It is main
The function of control panel detects and according to fitting including generation laser scans signal, the wavelength locking of laser, outer optical path signal
Algorithm, which calculates, is finally inversed by the concentration of laser gas, the demarcation control of stepper assemblies, multichannel data communication and output etc.；Signal
Process plate is amplified filtering process by the outer faint detectable signal of light path is received, and is formed certainly with the reference path signal of detector panel
Balance Treatment circuit, the interference component in outer optical path signal is effectively reduced, greatly improves signal to noise ratio, lifts lowest detection line；
Fiber beam splitting part includes fiber optic splitter, collimation lens and fiber coupler, by the output of the laser of laser be divided into interior light path,
Reference path and outer light path three parts；The functions such as there is LCD industry serial ports screen concentration to show, parameter is changed and demarcation controls.Swash
The power supply of light gas analyzer is civil power 220V, after power switch wave filter, is used from the relatively low 12V Switching Power Supplies of ripple
In the power supply of circuit board；The outside of laser gas analyzer is provided with USB, Ethernet interface, DB9, DB15, BNC connector, FC optical fiber couplings
Clutch etc., it is easy to the transmission of the communication of equipment, data output, detectable signal and laser signal；In addition, laser gas analyzer is also
Provided with air grid and fan, for radiating treatment, the too high normal work for influenceing laser of internal temperature is prevented.
As shown in Fig. 2 fiber optic collimator coupler, Fresnel Lenses, reflection are provided with open long-optical path optical-mechanical system
Mirror assembly, stepper assemblies, wedge-shaped window, corner reflector and mechanical adjustment seat.Infrared laser is replaced with feux rouges first, is adjusted
The position of machinery adjustment seat so that feux rouges is directed at corner reflector, completes the alignment work of light path；Outer light path laser optical fiber from swash
Light gas analyzer accesses, successively by fiber optic collimator coupler, the centre bore of Fresnel Lenses, wedge-shaped window, into air
Wedge-shaped window and corner reflector are reached in environment, and is reflected along original optical path and is returned to up to Fresnel Lenses, laser by corner reflector
Detector is converged to, detectable signal is sent to the retrieving concentration that laser gas is carried out in analyzer by shielded cable；Control
Stepper assemblies rotate speculum so that light path reaches detector by speculum, carries out the coefficient demarcation of system, improves and survey
Accuracy of measurement.
As shown in figure 3, after system electrification, hardware initialization operation is completed first, is obtained from gas parameter configuration module
Current measurement gas, initialization laser driving parameter, spectra inversion parameter, drives laser works, to ADC collections afterwards
Data are synchronized averagely, and by the wavelength location of characteristic gas in interior light path spectrum, the temperature of laser is finely adjusted, and are protected
The centre wavelength of card laser is not drifted about.Spectra collection module using outer light path spectrum configure the calculating of gas concentration, and
Constantly data are shown on industrial serial ports screen, gain control module is according to the intensity of outer light path spectrum, by controlling SPI interface
Chip, real-time adjustment circuit gain, makes it meet measurement demand.Communication module is tied measurement by RS232 or ethernet communication
Fruit, spectroscopic data are sent to host computer.
The preferred embodiment of utility model creation is the foregoing is only, is not created to limit the utility model,
All any modification, equivalent and improvement made within all spirit and principle created in the utility model etc., should be included in
Within the protection domain that the utility model is created.
Claims (4)
- A kind of 1. open long-optical path laser gas on-line monitoring system, it is characterised in that：Including laser gas analyzer and open Formula long light path optical-mechanical system two parts are put, laser driving plate, master board, signal transacting are provided with laser gas analyzer Plate, detector panel circuit, fiber beam splitting part and LCD industry serial ports screen；The function of master board includes producing laser scans Signal, the wavelength locking of laser, the detection of outer optical path signal simultaneously calculate the concentration for being finally inversed by laser gas, step according to fitting algorithm Demarcation control, multichannel data communication and the output of stepper motor component；Signal-processing board enters the outer faint detectable signal of light path is received Row amplification filtering process, self-balancing process circuit is formed with the reference path signal of detector panel, effectively reduces outer optical path signal In interference component, greatly improve signal to noise ratio, lift lowest detection line；Fiber beam splitting part includes fiber optic splitter, collimation Lens and fiber coupler, the laser output of laser is divided into interior light path, reference path and outer light path three parts；Open length Fiber optic collimator coupler, Fresnel Lenses, mirror assembly, stepper assemblies, wedged window are provided with light path optical-mechanical system Piece, corner reflector and mechanical adjustment seat, fiber beam splitting part is by fiber optic splitter, collimation lens and light in laser gas analyzer Fine coupler is formed, and fiber optic splitter is formed by 5%/95% and 50%/50% two kind, and the emergent light of laser is through fiber coupling Device accesses the input of 5%/95% fiber optic splitter, and 95% part is linked into open as outer light path with optical fiber in output end In long light path optical-mechanical system, 5% part is linked into the input of 50%/50% fiber optic splitter again, and output end is divided into two point Not Yong Yu wavelength locking and reference path, open long-optical path optical routing fiber optic collimator couples in open long-optical path optical-mechanical system Device, Fresnel Lenses, wedge-shaped window, corner reflector are formed, and laser is accessed by laser gas analyzer, through fiber optic collimator coupler Laser passes through Fresnel Lenses centre bore after collimation, and on the afterbody window of cabinet and corner reflector front end is respectively arranged with wedged window Piece, laser return to Fresnel Lenses along light path and converged, and regulation detector position receives spectral signal, open long-optical path ray machine System calibrating is made up of mirror assembly, demarcation gas pond, stepper assemblies in system, and stepper motor connects with mirror assembly Extension bar connects, and when carrying out system calibrating, master board control stepper motor rotates, and speculum and fiber optic collimator coupler are same Highly, laser reaches detector, forms nominal light successively by fiber optic collimator coupler, speculum, demarcation gas pond, speculum Paths.
- A kind of 2. open long-optical path laser gas on-line monitoring system according to claim 1, it is characterised in that：It is described Signal-processing board uses automatic growth control process circuit in laser gas analyzer.
- A kind of 3. open long-optical path laser gas on-line monitoring system according to claim 1, it is characterised in that：It is described Signal-processing board uses self-balancing process circuit in laser gas analyzer.
- A kind of 4. open long-optical path laser gas on-line monitoring system according to claim 1, it is characterised in that：It is open System calibrating is made up of mirror assembly, demarcation gas pond, stepper assemblies in formula long light path optical-mechanical system, stepper motor with it is anti- Penetrate mirror assembly to be connected with connecting rod, when carrying out system calibrating, master board control stepper motor rotates, and speculum is accurate with optical fiber Straight coupler sustained height, laser by fiber optic collimator coupler, speculum, demarcation gas pond, speculum, reach detection successively Device, form demarcation path channels.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720119385.2U CN207036686U (en) | 2017-01-23 | 2017-01-23 | Open long-optical path laser gas on-line monitoring system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201720119385.2U CN207036686U (en) | 2017-01-23 | 2017-01-23 | Open long-optical path laser gas on-line monitoring system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108303391A (en) * | 2018-05-04 | 2018-07-20 | 杭州春来科技有限公司 | Caliberating device applied to open path |
| CN112362597A (en) * | 2020-11-16 | 2021-02-12 | 安徽中科瀚海光电技术发展有限公司 | Multi-path laser gas monitoring system and monitoring method |
-
2017
- 2017-01-23 CN CN201720119385.2U patent/CN207036686U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108303391A (en) * | 2018-05-04 | 2018-07-20 | 杭州春来科技有限公司 | Caliberating device applied to open path |
| CN112362597A (en) * | 2020-11-16 | 2021-02-12 | 安徽中科瀚海光电技术发展有限公司 | Multi-path laser gas monitoring system and monitoring method |
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