CN108061722A - The detection device and detection method of a kind of carbonomonoxide concentration - Google Patents

The detection device and detection method of a kind of carbonomonoxide concentration Download PDF

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CN108061722A
CN108061722A CN201711268585.5A CN201711268585A CN108061722A CN 108061722 A CN108061722 A CN 108061722A CN 201711268585 A CN201711268585 A CN 201711268585A CN 108061722 A CN108061722 A CN 108061722A
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signal
calibration
discrete
background
differential
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CN108061722B (en
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张玉钧
陈东
尤坤
何莹
唐七星
刘国华
鲁冰
鲁一冰
范博强
刘建国
刘文清
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Hefei Institutes of Physical Science of CAS
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Hefei Institutes of Physical Science of CAS
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/3504Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
    • G01N21/359Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using near infrared light

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Abstract

The present invention disclose the detection device and method of carbonomonoxide concentration, and the light beam that the first beam splitter in detection device sends light source is divided into calibration beam and detects light beam;It is irradiated to after calibration beam collimator and steam correcting absorptive pool on photodetector and obtains calibration electric signal;Second beam splitter is divided into reference beam and measuring beam by light beam is detected;It is irradiated to after reference beam collimator on photodetector and obtains reference electrical signal;Emit after measuring beam collimator from the center of Fresnel Lenses and export, and reflection end is irradiated to behind region to be measured, light beam original road is reflected on photodetector and obtains measurement electric signal by reflection end;Difference amplifier carries out calculus of differences to reference electrical signal and measurement electric signal and obtains differential signal;Processor determines carbonomonoxide concentration in region to be measured according to calibration electric signal, reference electrical signal and differential signal.Detection device and detection method provided by the invention can improve the accuracy of detection of open area carbonomonoxide concentration laser spectrum measurement.

Description

The detection device and detection method of a kind of carbonomonoxide concentration
Technical field
The present invention relates to laser on-line checking field, detection device and detection more particularly to a kind of carbonomonoxide concentration Method.
Background technology
CO is common inflammable, explosive, the toxic process gas of the industries such as chemical industry, metallurgy, environment CO concentration monitor technologies Safe early warning being leaked for the gas in Wei Hua areas, reliable basis are provided.Optical detecting method has non-cpntact measurement, sensitivity Outstanding advantages of height, long lifespan, by being combined with long light path technology, can realize being completely covered for region security monitoring, be One important directions of industry security monitoring technology development at present.
Infrared semiconductor laser spectrum detection technique is the fingerprint absorption characteristic to infrared spectrum based on gas molecule, is utilized The characteristic spectrum of target gas molecules absorbs the qualitative and quantitative detection realized to gas.Field is monitored in region security, by There is high optical power density in laser technology, thus can realize the continuous gas leakage safety monitoring of km grade scope.
Direct absorption spectroscopy techniques and balance Detection Techniques are the sides of predominantly detecting of current infrared laser spectroscopy detection method Method.Wherein, direct absorption spectroscopy techniques are by the strong direct detection of transmission light, utilize the fitting of background light intensity and normalized reality The direct amendment of existing light intensity variation, but the absorption of normal conditions gas is relatively weak, and direct absorption spectrum is shown as in stronger background On a minor variations, cause the signal-to-noise ratio of measuring signal and sensitivity low, so as to reduce the accuracy of detection of gas concentration. Balance detection technology is a kind of highly sensitive Detection Techniques based on double photo paths, reference path and external inspection using no absorption The difference for surveying optical path signal offsets processing, achievees the purpose that effectively to inhibit background and common-mode noise.But autobalance detection skill Art can not obtain light intensity signal, it is difficult to complete absorption signal and the normalization of light intensity, reduce the accuracy of detection of gas concentration. Especially when measuring environment is open area, since the environmental factors such as dust, mist, the haze in environment can cause light intensity signal to be deposited In larger fluctuation, so that the accuracy of detection of carbonomonoxide concentration can be reduced further.
Therefore, the accuracy of detection of open area carbonomonoxide concentration how is improved, becoming those skilled in the art, there is an urgent need for solutions Certainly the technical issues of.
The content of the invention
The object of the present invention is to provide the detection device and detection method of a kind of carbonomonoxide concentration, to improve open area The accuracy of detection of carbonomonoxide concentration.
To achieve the above object, the present invention provides following schemes:
A kind of detection device of carbonomonoxide concentration, the detection device is using laser as detection light source, the laser The near-infrared light beam that device launch wavelength is continuously scanned in setting wave-length coverage periodically;First beam splitter is by the near infrared light Beam is divided into calibration beam and detection light beam;
The calibration beam obtains collimation calibration beam, the collimation calibration beam warp after calibration optical collimator collimation It crosses after steam correcting absorptive pool to be irradiated on calibration light photodetector and carries out opto-electronic conversion, obtain calibration electric signal, the calibration light The calibration electric signal is sent to processor by photodetector, wherein, it is sealed with standard atmospheric pressure in the steam correcting absorptive pool CO gas known to lower concentration;
The detection light beam is divided into reference beam and measuring beam by the second beam splitter;
The reference beam is irradiated on reference light photodetector after with reference to optical collimator collimation and carries out photoelectricity turn It changes, obtains reference electrical signal, the reference electrical signal is sent respectively to differential amplifier circuit by the reference light photodetector With the processor;
The measuring beam emits output, the phenanthrene alunite after measurement optical collimator collimation by the center of Fresnel Lenses You are irradiated to reflection end by the light beam of lens transmitting output behind region to be measured, wherein, the Fresnel Lenses and the reflection End is correspondingly arranged at the both ends in the region to be measured, and light beam original road is reflected on measurement light photodetector by the reflection end, Measurement electric signal is obtained, the measurement electric signal is sent to the difference amplifier by the measurement light photodetector;
The difference amplifier carries out calculus of differences to the reference electrical signal and the measurement electric signal, obtains difference letter Number, and the differential signal is sent to the processor;The processor according to it is described calibration electric signal, it is described refer to telecommunications Number and the differential signal determine the concentration of carbon monoxide in the region to be measured.
Optionally, the detection device further includes the display being connected to the processor, for showing the area to be measured The concentration of carbon monoxide in domain.
Optionally, the detection device further includes laser controller and signal generator, the laser controller with it is described Laser connects, and the signal generator is connected with the laser controller, and the signal generator is believed for generating sawtooth waveforms Number, the DC current superposition generation that the sawtooth signal and the laser controller are preset generation by the laser controller swashs The driving current of light device, the laser exist according to the preset temperature and the driving current launch wavelength of the laser controller The near-infrared light beam that setting wave-length coverage periodically continuously scans.
Optionally, the signal generator is connected to the processor, the signal generator be additionally operable to generate with it is described The square-wave signal of sawtooth signal synchronization, the processor calibrate telecommunications according to the square-wave signal synchronous acquisition Number, the reference electrical signal and the differential signal.
A kind of detection method of carbonomonoxide concentration, the detection method are used for the detection device, the detection side Method includes:
Obtain calibration electric signal, reference electrical signal and differential signal;
Discretization data acquisition is carried out to the calibration electric signal, the reference electrical signal and the differential signal respectively, Obtain with the corresponding discrete calibration signal of the calibration electric signal, discrete reference signal corresponding with the reference electrical signal and Discrete differential signal corresponding to the differential signal;
To in the spectrogram of the discrete differential signal, being carried out without the data in the background spectrum region of carbon monoxide absorption Fitting obtains the background signal of differential signal;
The discrete reference signal is fitted, obtains the background signal of reference signal;
It is true according to the background signal of the background signal of the differential signal, the gain of difference amplifier and the reference signal Determine the background signal of measuring signal;
Discrete absorption is determined according to the gain of the background signal of differential signal, the discrete differential signal and difference amplifier Signal;
The integration Absorption Line of measuring signal is determined according to the background signal of the discrete absorption signal and the measuring signal By force;
To in the spectrogram of the discrete calibration signal, being carried out without the data in the background spectrum region of carbon monoxide absorption Fitting obtains the background signal of calibration signal;
Background signal and the discrete calibration signal to the calibration signal are normalized, and obtain normalization school Calibration signal;
The normalization calibration signal is fitted, the integration Absorption Line for obtaining calibration signal is strong;
According to the integration Absorption Line of integration strong, the described calibration signal of Absorption Line of the measuring signal is strong, steam correcting absorptive pool Length, the concentration of CO gas determines an oxidation in region to be measured in the length of optical path and the steam correcting absorptive pool The concentration of carbon.
Optionally, in the spectrogram to the discrete differential signal, without the background spectrum area of carbon monoxide absorption Before the data in domain are fitted, further include:
The discrete calibration signal after correction is obtained, the discrete calibration signal after the correction is described discrete for multiple cycles The average value of calibration signal;
The discrete reference signal after correction is obtained, the discrete reference signal after the correction is described discrete for multiple cycles The average value of reference signal;
The discrete differential signal after correction is obtained, the discrete differential signal after the correction is described discrete for multiple cycles The average value of differential signal.
Optionally, the background signal according to the discrete absorption signal and the measuring signal determines measuring signal It is strong to integrate Absorption Line, specifically includes:
Normalization absorption signal is determined according to the background signal of the discrete absorption signal and the measuring signal;
The normalized signal is fitted using Lorentzian, the integration Absorption Line for obtaining measuring signal is strong.
Optionally, the gain of the background signal, difference amplifier according to the differential signal and the reference signal Background signal determine the background signal of measuring signal, specifically include:
According to formula:Determine the background signal of measuring signal, wherein, SB (n) represents measurement The background signal of signal, δ (n) represent the background signal of differential signal, and G represents the gain of difference amplifier, and RB (n) represents reference The background signal of signal.
Optionally, the gain according to the background signal of differential signal, the discrete differential signal and difference amplifier It determines discrete absorption signal, specifically includes:
According to formula:Determine discrete absorption signal, wherein, A (n) represents discrete absorption signal, δ (n) represents the background signal of differential signal, and G represents the gain of difference amplifier, and M (n) represents discrete differential signal.
Optionally, the integration Absorption Line of integration strong, the described calibration signal of Absorption Line according to the measuring signal it is strong, The concentration of CO gas determines area to be measured in the length of steam correcting absorptive pool, the length of optical path and the steam correcting absorptive pool The concentration of carbon monoxide, specifically includes in domain:
According to formula:Determine the concentration of carbon monoxide in region to be measured, wherein, C represents region to be measured The mean concentration of middle carbon monoxide, AS represent that the integration Absorption Line of measuring signal is strong, and AJ represents the integration Absorption Line of calibration signal By force, L0Represent the length of steam correcting absorptive pool, L represents the length of optical path, C0Represent CO gas in steam correcting absorptive pool Concentration.
The specific embodiment provided according to the present invention, the invention discloses following technique effects:
The near-infrared light beam that laser is sent is divided into calibration beam and detection light beam by the present invention, wherein, detection light beam is again It is divided into reference beam and measuring beam, using signal cancellation treatment technology in reference path and optical path, offsets reference light Road and the common mode component of optical path signal can not only inhibit the additional noise during laser noise and beam Propagation, improve The signal-to-noise ratio of differential signal, moreover it is possible to the DC component of measuring signal is reduced, so as to improve the accuracy of detection of carbonomonoxide concentration.Together When, the background signal of the invention by constructing differential signal and reference signal obtains the light intensity change information of optical path, sharp Influence of the light intensity fluctuation to accuracy of detection caused by eliminating the variation of optical path beam propagation property with normalized, into one Step ensure that the accuracy of detection of open area carbonomonoxide concentration.
Description of the drawings
It in order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to institute in embodiment Attached drawing to be used is needed to be briefly described, it should be apparent that, the accompanying drawings in the following description is only some implementations of the present invention Example, for those of ordinary skill in the art, without creative efforts, can also obtain according to these attached drawings Obtain other attached drawings.
Fig. 1 is the structure diagram for the detection device that the embodiment of the present invention 1 provides;
Fig. 2 is the flow chart for the detection method that the embodiment of the present invention 2 provides.
Specific embodiment
Below in conjunction with the attached drawing in the embodiment of the present invention, the technical solution in the embodiment of the present invention is carried out clear, complete Site preparation describes, it is clear that described embodiment is only part of the embodiment of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, those of ordinary skill in the art are obtained every other without making creative work Embodiment belongs to the scope of protection of the invention.
The object of the present invention is to provide the detection device and detection method of a kind of carbonomonoxide concentration, to improve open area The accuracy of detection of carbonomonoxide concentration.
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, it is below in conjunction with the accompanying drawings and specific real Applying mode, the present invention is described in further detail.
Embodiment 1:
As shown in Figure 1, a kind of detection device of carbonomonoxide concentration, the detection device is using laser 1 as detection light Source, the near-infrared light beam that 1 launch wavelength of laser is continuously scanned in setting wave-length coverage periodically;First beam splitter 2 The near-infrared light beam is divided into calibration beam and detection light beam;
The calibration beam obtains collimation calibration beam, the collimation calibration beam after calibration optical collimator 3 collimates It is irradiated to after steam correcting absorptive pool 4 on calibration light photodetector 5 and carries out opto-electronic conversion, obtain calibration electric signal, the school The calibration electric signal is sent to processor 6 by quasi-optical photodetector 5, wherein, it is sealed with standard in the steam correcting absorptive pool 4 CO gas known to concentration under atmospheric pressure;
The detection light beam is divided into reference beam and measuring beam by the second beam splitter 7;
The reference beam is irradiated on reference light photodetector 9 after being collimated with reference to optical collimator 8 and carries out photoelectricity Conversion, obtains reference electrical signal, and the reference electrical signal is sent respectively to differential amplification electricity by the reference light photodetector 9 Road 10 and the processor 6;
The measuring beam emits output after measurement optical collimator 11 collimates by the center of Fresnel Lenses 12, described The light beam of the transmitting output of Fresnel Lenses 12 is irradiated to reflection end 13 behind region to be measured, wherein, the Fresnel Lenses 12 The both ends in the region to be measured are correspondingly arranged at the reflection end 13, light beam original road is reflected into measurement light by the reflection end 13 On photodetector 14, measurement electric signal is obtained, the measurement electric signal is sent to institute by the measurement light photodetector 14 State difference amplifier 10;
The difference amplifier 10 carries out calculus of differences to the reference electrical signal and the measurement electric signal, obtains difference Signal, and the differential signal is sent to the processor 6;The processor 6 is according to the calibration electric signal, the reference Electric signal and the differential signal determine the concentration of carbon monoxide in the region to be measured.
Preferably, detection device described in the present embodiment further includes the display 15 being connected with the processor 6, for showing Show the concentration of carbon monoxide in the region to be measured.The detection device further includes laser controller 16 and signal generator 17, The laser controller 16 is connected with the laser 1, and the signal generator 17 is connected with the laser controller 16, described Signal generator 17 is for generating the adjustable sawtooth signal of amplitude, and the laser controller 16 is by the sawtooth signal and institute The driving current of the DC current superposition generation laser 1 of the default generation of laser controller 16 is stated, the laser 1 is according to described What the preset temperature of laser controller 16 and the driving current launch wavelength were continuously scanned in setting wave-length coverage periodically Near-infrared light beam.Wherein, wave-length coverage is set as (1566.6396nm-a, 1566.6396nm+a), and a is constant, and unit is nm. The amplitude for adjusting sawtooth signal can corresponding adjusting wavelength scope.The signal generator 17 is connected with the processor 6, described Signal generator 17 is additionally operable to generate the square-wave signal synchronous with the sawtooth signal, and the processor 6 is according to the square Electric signal, the reference electrical signal and the differential signal are calibrated described in shape ripple signal synchronous collection.
As shown in Figure 1, the present embodiment uses near-infrared distributed Feedback of the output center wavelength near 1.57 μm Detection light source of the semiconductor laser (Distributed Feedback Laser, DFB) as CO gases, laser controller 16 By controlling the center wavelength tuning of light beam that the temperature of semiconductor and the driving current of laser 1 export laser 1 to CO The centre of absorption line, signal generating circuit 17 generate two paths of signals, be all the way the sawtooth signal of 100Hz, another way be with The square-wave signal of the sawtooth signal synchronization.Square-wave signal is sent to processor 6 by signal generating circuit 17, as place The trigger signal that device 6 carries out signal acquisition is managed, to ensure the scanning signal of laser transmitting and the periodic signal of processor acquisition Synchronism in time domain.
As described in Figure 1, the present embodiment is provided with mainframe box 18, wherein, the laser 1, the first beam splitter 2, calibration light Collimator 3, steam correcting absorptive pool 4, calibration light photodetector 5, processor 6, differential amplifier circuit 10, display 15, laser control Device 16 and signal generator 17 processed are arranged in the mainframe box 18, form instrument host.The present embodiment is additionally provided with transmitting Hold outer cover 19, wherein, second beam splitter 7, with reference to optical collimator 8, reference light photodetector 9, measurement optical collimator 11, Fresnel Lenses 12, measurement light photodetector 14 are arranged in the transmitting terminal outer cover 19, form transmitting terminal, wherein, Window is offered on the transmitting terminal outer cover 19, and the window is located on the emitting light path of the transmitting terminal, in the window On be provided with quartz window sheet 20.
The light beam that laser 1 is sent is exported through fiber coupling, the first beam splitter 2 be 1 × 2 fiber optic splitter, the first beam splitting Light beam is pressed 1 by device 2:9 are divided into two beams, compared with dim light Shu Zuowei calibration beams, compared with strong beam as detection light beam.The present embodiment is in institute It states and the first low-pass filtering amplifying circuit 27 is provided between calibration light photodetector 5 and the processor 6, the calibration light light The calibration electric signal is sent to the first low-pass filtering amplifying circuit 27 that is sent to and is filtered and amplifies by electric explorer 5 Processing carries out data acquisition and data processing as calibration signal, the processor 6 to the calibration signal.
In the present embodiment, input optical fibre coupler 23 is additionally provided on transmitting terminal outer cover 19.Light beam is detected through output light Fine coupler 21 is connected with outer light path, is transferred to transmitting terminal by single mode optical fiber 22, is connected with the optical system in transmitting terminal.Coupling The light beam closed into transmitting terminal is divided into 2 through the second beam splitter 7:8 two beams, second beam splitter 7 are 1 × 2 fiber optic splitter, In be used as compared with dim light beam with reference to light beam, stronger light beam is as measuring beam.The reference beam passes through accurate with reference to optical collimator 8 It is irradiated to after straight on reference light photodetector 9 and carries out opto-electronic conversion, obtain calibration electric signal, the reference light photodetector 9 are connected the reference electrical signal through the first signal-transmitting cable interface 24 with host, will by multicore signal-transmitting cable 25 Signal transmission returns host, and the second low-pass filtering amplification electricity is transferred to by the secondary signal transmission cable interface 26 on mainframe box 18 Road 28, the signal exported after filtered amplification are divided into two-way, are sent to the progress analog-to-digital conversion of processor 6 all the way and digital signal is adopted Collection, in addition send differential amplifier circuit 10 all the way.Measuring beam is collimated the Fresnel Lenses from transmitting terminal by measurement optical collimator 11 The transmitting output of 12 centers, light beam is after detection zone, by being placed on after the other end of reflection end 13 of light path reflects by former light Road returns, and the reflected beams are collected by Fresnel Lenses 12 and focused on the photosurface of measurement light photodetector 14, wherein, it surveys It is infrared photoelectric detector to measure light photodetector 14, after infrared photoelectric detector carries out opto-electronic conversion to light beam, output letter It number is connected through the first signal-transmitting cable interface 24 with host, signal transmission is returned by host by multicore signal-transmitting cable 25, 3rd low-pass filtering amplifying circuit 29 is transferred to by secondary signal transmission cable interface 26, the output signal of filtered amplification is made Differential amplifier circuit 10 is sent to for measuring signal.Differential amplifier circuit 10 carries out calculus of differences, output to the signal received Signal is sent to processor 6 as differential signal and carries out analog-to-digital conversion and digital signal acquiring, and processor 6 is by synchronous acquisition Reference signal, calibration signal and differential signal carry out data processing, and the CO average gas concentration of light path is calculated, and leads to It crosses liquid crystal display 15 to show, the display 15 in the present embodiment is liquid crystal display.As shown in Figure 1, the one of mainframe box 18 The exhaust outlet that fan 33 is set is offered on a side wall, the heat in mainframe box 18 is shed by fan 33.In mainframe box 18 In be additionally provided with D.C. regulated power supply 32, the D.C. regulated power supply 32 is for giving each power device to provide electric energy, the direct current Regulated power supply 32 is connected with general supply socket 28, is connected by the general supply socket 28 with external power supply.In mainframe box 18 The main power switch 31 being connected with the D.C. regulated power supply 32 is additionally provided on side wall, is started by the main power switch 31 Or close the detection device.
The present embodiment using near-infrared semiconductor laser as detection light source, by CO gases near infrared light The detection of an island features absorption line near 1.56 μm of area is composed, it is dense to the CO gases in dangerization region with reference to long-range optical system Degree carries out highly sensitive, high-resolution on-line checking.
Embodiment 2:
As shown in Fig. 2, a kind of detection method of carbonomonoxide concentration, the detection method is for described in embodiment 1 Detection device, the detection method include:
Step 201:Obtain calibration electric signal, reference electrical signal and differential signal.
Step 202:Discretization number is carried out to the calibration electric signal, the reference electrical signal and the differential signal respectively According to acquisition, discrete calibration signal corresponding with the calibration electric signal, discrete reference corresponding with the reference electrical signal are obtained Signal, the discrete differential signal corresponding with the differential signal.
Step 203:To in the spectrogram of the discrete differential signal, the background spectrum region that absorbs without carbon monoxide Data are fitted, and obtain the background signal of differential signal.
Reference signal does not include CO gas sorption features, shows as slope background;And when measuring light and passing through detection zone, if There are CO gases in optical path, absorption, measuring signal S will be generated within the measurement optical scanning cycle0Include absorption information, Show as a characteristic absorption in the background of slope.It is put by adjusting the first low-pass filtering amplifying circuit 27 and the second low-pass filtering The gain of big circuit 28, the differential signal that ideally differential amplifier circuit 10 exports are complete in the part that no gas absorbs It offsets, but is unable to reach due to the variation of optical path delustring under actual working state and preferably offsets effect, show certain Background, can obtain light path Extinction characteristics using this background characteristics.The background signal for defining discrete differential signal M (n) is δ (n), it is fitted to obtain by the white space without CO spectral absorption in discrete differential signal M (n) data sequences, fitting function is:
δ (n)=a0+a1n+a2n2
Wherein:a0、a1、a2Represent the fitting parameter of differential signal, n represents the discrete points data ordinal number of signal sequence sampling.
Step 204:The discrete reference signal is fitted, obtains the background signal of reference signal.
Reference signal does not include CO gas sorption features, shows as slope background, the background of reference signal can be by referring to The directly fitting of the data sequence of signal obtains, and fitting function is:
RB (n)=b0+b1n+b2n2
Wherein:b0、b1、b2Represent the fitting parameter of reference signal.
Step 205:According to the back of the body of the background signal of the differential signal, the gain of difference amplifier and the reference signal Scape signal determines the background signal of measuring signal.
Step 206:It is determined according to the gain of the background signal of differential signal, the discrete differential signal and difference amplifier Discrete absorption signal.
Step 207:The product of measuring signal is determined according to the background signal of the discrete absorption signal and the measuring signal Divide Absorption Line strong.
Step 208:To in the spectrogram of the discrete calibration signal, the background spectrum region that absorbs without carbon monoxide Data are fitted, and obtain the background signal of calibration signal.
Step 209:Background signal and the discrete calibration signal to the calibration signal are normalized, and obtain Normalize calibration signal.
Step 210:The normalization calibration signal is fitted, the integration Absorption Line for obtaining calibration signal is strong.
Calibration signal is the calibration direct absorption spectrum signal of light path, and the strong computational methods class of Absorption Line is integrated with optical path Seemingly, the background signal JB (n) of calibration signal is obtained by the Background fitting of calibration signal, using background signal to calibration signal into Row normalized obtains normalization calibration signal JC (n), and normalization calibration signal JC (n) is fitted using Lorentzian To the strong AJ of integration Absorption Line of calibration signal.
The background signal JB (n) of calibration signal also with do not have in calibration signal J (n) data sequences CO gases absorb Data segment is fitted to obtain, and fitting formula is:
JB (n)=c0+c1n+c2n2
Wherein:c0、c1、c2For the fitting parameter of calibration signal.
Calibration signal normalized obtain normalization calibration signal JC (n) formula be:
The fitting formula of the strong AJ of integration Absorption Line of calibration signal is:
Wherein:AJ、γ'L、n'0For fitting parameter.
Step 211:According to the integration Absorption Line of integration strong, the described calibration signal of Absorption Line of the measuring signal is strong, school The concentration of CO gas determines region to be measured in the length of quasi- absorption cell, the length of optical path and the steam correcting absorptive pool The concentration of middle carbon monoxide.
Preferably, step 203 is being performed:To in the spectrogram of the discrete differential signal, being absorbed without carbon monoxide Before the data in background spectrum region are fitted, further include:
The discrete calibration signal after correction is obtained, the discrete calibration signal after the correction is described discrete for multiple cycles The average value of calibration signal;
The discrete reference signal after correction is obtained, the discrete reference signal after the correction is described discrete for multiple cycles The average value of reference signal;
The discrete differential signal after correction is obtained, the discrete differential signal after the correction is described discrete for multiple cycles The average value of differential signal.
Specifically, step 207:Measurement letter is determined according to the background signal of the discrete absorption signal and the measuring signal Number integration Absorption Line it is strong, specifically include:
Step 2071:Determine that normalization absorbs letter according to the background signal of the discrete absorption signal and the measuring signal Number.
The intensity of CO gas absorption signals is directly proportional to measurement light intensity on optical path, measures the back of the body of the light intensity by measuring signal Scape signal description changes influence to detection to eliminate optical path delustring, the present invention using normalization absorption signal σ (n) into The Inversion Calculation of promoting the circulation of qi bulk concentration, calculation formula are:
Step 2072:The normalized signal is fitted using Lorentzian, the integration for obtaining measuring signal is inhaled Take-up is strong.
Normalization absorption signal shows as gas molecules sorb spectral line line style, can be retouched under normal pressure with Lorentzian It states, the strong AS of integration Absorption Line of measuring signal is defined as its integral area, and fitting function relation is:
Wherein:AS、γL、n0Represent fitting parameter.
Specifically, step 205:According to the background signal of the differential signal, the gain of difference amplifier and the reference The background signal of signal determines the background signal of measuring signal, specifically includes:
According to formula:Determine the background signal of measuring signal, wherein, SB (n) represents measurement The background signal of signal, δ (n) represent the background signal of differential signal, and G represents the gain of difference amplifier, and RB (n) represents reference The background signal of signal.
Specifically, step 206:According to the background signal of differential signal, the discrete differential signal and difference amplifier Gain determines discrete absorption signal, specifically includes:
According to formula:Determine discrete absorption signal, wherein, A (n) represents discrete absorption signal, δ (n) represents the background signal of differential signal, and G represents the gain of difference amplifier, and M (n) represents discrete differential signal.
Specifically, step 211:It is absorbed according to the integration of integration strong, the described calibration signal of Absorption Line of the measuring signal Line is strong, the concentration of CO gas determines in the length of steam correcting absorptive pool, the length of optical path and the steam correcting absorptive pool The concentration of carbon monoxide, specifically includes in region to be measured:
According to formula:Determine the concentration of carbon monoxide in region to be measured, wherein, C represents region to be measured The mean concentration of middle carbon monoxide, AS represent that the integration Absorption Line of measuring signal is strong, and AJ represents the integration Absorption Line of calibration signal By force, L0Represent the length of steam correcting absorptive pool, L represents the length of optical path, C0Represent CO gas in steam correcting absorptive pool Concentration.
Detection method provided in this embodiment using the processing that offsets of reference path and optical path signal, offsets reference On the one hand the common mode component of light path and optical path signal reaches and inhibits additional noise during laser noise and beam Propagation On the other hand purpose can also reduce the DC component of detection signal, realize effective amplification of absorption signal, increase detecting system Range of dynamic measurement.
The present invention obtains the light intensity change information of optical path, utilizes normalizing by constructing optical path background signal Change processing eliminates influence of the light intensity fluctuation to detection caused by the variation of optical path beam propagation property, and combines built-in calibration Calibration pool realizes the accurate on-line checking of open area carbonomonoxide concentration.
Each embodiment is described by the way of progressive in this specification, the highlights of each of the examples are with other The difference of embodiment, just to refer each other for identical similar portion between each embodiment.
Specific case used herein is set forth the principle of the present invention and embodiment, and above example is said It is bright to be only intended to help the method and its core concept for understanding the present invention;Meanwhile for those of ordinary skill in the art, foundation The thought of the present invention, in specific embodiments and applications there will be changes.In conclusion this specification content is not It is interpreted as limitation of the present invention.

Claims (10)

1. a kind of detection device of carbonomonoxide concentration, which is characterized in that the detection device using laser as detection light source, The near-infrared light beam that the laser emission wavelength is continuously scanned in setting wave-length coverage periodically;First beam splitter is by described in Near-infrared light beam is divided into calibration beam and detection light beam;
The calibration beam obtains collimation calibration beam after calibration optical collimator collimation, and the collimation calibration beam is by school It is irradiated to after quasi- absorption cell on calibration light photodetector and carries out opto-electronic conversion, obtain calibration electric signal, the calibration light photoelectricity The calibration electric signal is sent to processor by detector, wherein, it is dense that normal atmosphere pressure is sealed in the steam correcting absorptive pool CO gas known to degree;
The detection light beam is divided into reference beam and measuring beam by the second beam splitter;
The reference beam is irradiated on reference light photodetector after with reference to optical collimator collimation and carries out opto-electronic conversion, obtains The reference electrical signal is sent respectively to differential amplifier circuit and described by reference electrical signal, the reference light photodetector Processor;
The measuring beam emits output after measurement optical collimator collimation by the center of Fresnel Lenses, and the Fresnel is saturating The light beam of mirror transmitting output is irradiated to reflection end behind region to be measured, wherein, the Fresnel Lenses and the reflection end pair The both ends in the region to be measured should be arranged on, light beam original road is reflected on measurement light photodetector, obtains by the reflection end Electric signal is measured, the measurement electric signal is sent to the difference amplifier by the measurement light photodetector;
The difference amplifier carries out calculus of differences to the reference electrical signal and the measurement electric signal, obtains differential signal, And the differential signal is sent to the processor;The processor is according to the calibration electric signal, the reference electrical signal The concentration of carbon monoxide in the region to be measured is determined with the differential signal.
2. detection device according to claim 1, which is characterized in that the detection device is further included to be connected with the processor The display connect, for showing the concentration of carbon monoxide in the region to be measured.
3. detection device according to claim 1, which is characterized in that the detection device further includes laser controller and letter Number generator, the laser controller are connected with the laser, and the signal generator is connected with the laser controller, institute Signal generator is stated for generating sawtooth signal, the laser controller is by the sawtooth signal and the laser controller The driving current of the DC current superposition generation laser of default generation, the laser is according to the default of the laser controller The near-infrared light beam that temperature and the driving current launch wavelength are continuously scanned in setting wave-length coverage periodically.
4. detection device according to claim 3, which is characterized in that the signal generator is connected to the processor, The signal generator is additionally operable to generate the square-wave signal synchronous with the sawtooth signal, and the processor is according to the square Electric signal, the reference electrical signal and the differential signal are calibrated described in shape ripple signal synchronous collection.
5. a kind of detection method of carbonomonoxide concentration, which is characterized in that the detection method is used for according in claim 1-4 Any one of them detection device, the detection method include:
Obtain calibration electric signal, reference electrical signal and differential signal;
Discretization data acquisition is carried out to the calibration electric signal, the reference electrical signal and the differential signal respectively, is obtained With the corresponding discrete calibration signal of the calibration electric signal, discrete reference signal corresponding with the reference electrical signal, with it is described Discrete differential signal corresponding to differential signal;
To in the spectrogram of the discrete differential signal, the data in the background spectrum region that no carbon monoxide absorbs are intended It closes, obtains the background signal of differential signal;
The discrete reference signal is fitted, obtains the background signal of reference signal;
It determines to survey according to the background signal of the background signal of the differential signal, the gain of difference amplifier and the reference signal Measure the background signal of signal;
Determine that discrete absorb is believed according to the gain of the background signal of differential signal, the discrete differential signal and difference amplifier Number;
Determine that the integration Absorption Line of measuring signal is strong according to the background signal of the discrete absorption signal and the measuring signal;
To in the spectrogram of the discrete calibration signal, the data in the background spectrum region that no carbon monoxide absorbs are intended It closes, obtains the background signal of calibration signal;
Background signal and the discrete calibration signal to the calibration signal are normalized, and obtain normalization calibration letter Number;
The normalization calibration signal is fitted, the integration Absorption Line for obtaining calibration signal is strong;
According to the integration Absorption Line of integration strong, the described calibration signal of Absorption Line of the measuring signal is strong, length of steam correcting absorptive pool The concentration of CO gas determines carbon monoxide in region to be measured in degree, the length of optical path and the steam correcting absorptive pool Concentration.
6. detection method according to claim 5, which is characterized in that the spectrogram to the discrete differential signal In, before the data in the background spectrum region that no carbon monoxide absorbs are fitted, further include:
The discrete calibration signal after correction is obtained, the discrete calibration signal after the correction is the discrete calibration in multiple cycles The average value of signal;
The discrete reference signal after correction is obtained, the discrete reference signal after the correction is the discrete reference in multiple cycles The average value of signal;
The discrete differential signal after correction is obtained, the discrete differential signal after the correction is the discrete differential in multiple cycles The average value of signal.
7. detection method according to claim 5, which is characterized in that described according to the discrete absorption signal and the survey The background signal of amount signal determines that the integration Absorption Line of measuring signal is strong, specifically includes:
Normalization absorption signal is determined according to the background signal of the discrete absorption signal and the measuring signal;
The normalized signal is fitted using Lorentzian, the integration Absorption Line for obtaining measuring signal is strong.
8. detection method according to claim 5, which is characterized in that the background signal according to the differential signal, The background signal of the gain of difference amplifier and the reference signal determines the background signal of measuring signal, specifically includes:
According to formula:Determine the background signal of measuring signal, wherein, SB (n) represents measuring signal Background signal, δ (n) represent differential signal background signal, G represent difference amplifier gain, RB (n) represent reference signal Background signal.
9. detection method according to claim 5, which is characterized in that the background signal according to differential signal, described The gain of discrete differential signal and difference amplifier determines discrete absorption signal, specifically includes:
According to formula:Determine discrete absorption signal, wherein, A (n) represents discrete absorption signal, δ (n) Represent the background signal of differential signal, G represents the gain of difference amplifier, and M (n) represents discrete differential signal.
10. detection method according to claim 5, which is characterized in that described to be absorbed according to the integration of the measuring signal Integrate strong Absorption Line, the length of steam correcting absorptive pool, the length of optical path and the calibration of strong, the described calibration signal of line absorb The concentration of CO gas determines the concentration of carbon monoxide in region to be measured in pond, specifically includes:
According to formula:Determine the concentration of carbon monoxide in region to be measured, wherein, C is represented one in region to be measured The mean concentration of carbonoxide, AS represent that the integration Absorption Line of measuring signal is strong, and AJ represents that the integration Absorption Line of calibration signal is strong, L0 Represent the length of steam correcting absorptive pool, L represents the length of optical path, C0CO gas is dense in expression steam correcting absorptive pool Degree.
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CN108663341A (en) * 2018-06-29 2018-10-16 深圳大学 A kind of medical respiration carbon dioxide concentration measurement system
CN109285613A (en) * 2018-09-13 2019-01-29 中国核动力研究设计院 The method of reactor pressure vessel vibration monitoring
CN112763434A (en) * 2019-10-21 2021-05-07 合肥新标智能设备有限公司 Alcohol concentration measuring instrument
CN113218905A (en) * 2021-04-27 2021-08-06 深圳市利拓光电有限公司 Carbon monoxide detection system and method based on 2327nm laser
CN113899703A (en) * 2021-09-29 2022-01-07 安徽农业大学 Linear broadening eliminating method under wavelength deviation
CN113899703B (en) * 2021-09-29 2022-07-05 安徽农业大学 Linear broadening eliminating method under wavelength deviation
CN114739877A (en) * 2022-03-29 2022-07-12 安徽理工大学 System and method for detecting concentration of free silica in coal dust
CN114739877B (en) * 2022-03-29 2022-11-15 安徽理工大学 System and method for detecting concentration of free silica in coal dust
US11940376B2 (en) 2022-03-29 2024-03-26 Anhui University of Science and Technology System and method for detecting concentration of free SiO2 in coal dust
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CN116559105B (en) * 2023-07-06 2023-11-14 国科大杭州高等研究院 Linearization readout circuit system based on gas infrared spectrum detection technology
CN118501097A (en) * 2024-07-17 2024-08-16 宁波海尔欣光电科技有限公司 Semi-open type atmospheric ammonia concentration detection system and measurement method

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