CN102288577A - System and method for measuring gas parameters by utilizing laser spectrum - Google Patents

Abstract

The invention discloses a system and method for measuring gas parameters by utilizing a laser spectrum. In the system for measuring the gas parameters by utilizing the laser spectrum, a locking device locks wavelength of a laser signal emitted by a laser output head of a first laser generator to be at a center position of an absorption line of a target molecule in a target molecule sample cell in which a first locking channel is located, a control device acquires the laser signal which is emitted by the laser output head of the first laser generator, is detected by a detector and enters into a receiving light path device and a sample measuring channel as well as a laser signal which is emitted by the laser output head of a second laser generator and enters into the sample measuring channel, analog-digital conversion is carried out on the acquired laser signals, and concentration of the measured target gas is measured according to analog-digital conversion result. The measuring speed of the system is restricted by the time for the control device to acquire data while minimum of the current time for acquiring data is in microsecond, and response time of a laser demodulation frequency is greatly improved compared with the prior art, thus the measuring speed is improved and time consumption is reduced.

Description

A kind of system and method that utilizes laser spectrum measurement gas parameter

Technical field

The application relates to the laser measuring technique field, particularly relates to a kind of system and method that utilizes laser spectrum measurement gas parameter.

Background technology

The laser absorption spectrum technology is a kind of technology of measuring measured target gas temperature and concentration, be specially: many absorption lines to a certain component in the gas are measured, obtain the absorptivity of this component, further according to the corresponding relation of absorptivity and measured target gas temperature, and the corresponding relation of the concentration of absorptivity and measured target gas, the concentration of acquisition measured target gas temperature and measured target gas.

Laser absorption spectrum technology commonly used at present comprises direct absorption spectroscopy and Wavelength modulation spectroscopy method, these two kinds of methods are referred to as the scanning wavelength method, the spectrum of the laser by writing down certain wavelength band, carry out integration to spectral line, thereby obtain the integration absorptance R of two absorption lines:

$R=\frac{\underset{v_1}{\overset{v_1^{\&prime;}}{\&Integral;}}{S}_1\left(T\right){\mathrm{\&phi;}}_1(v-v_{01})\mathrm{dv}}{\underset{v_2}{\overset{v_2^{\text{\&prime;}}}{\&Integral;}}{S}_2\left(T\right){\mathrm{\&phi;}}_2(v-v_{02})\mathrm{dv}}=\frac{S_1\left(T_0\right)}{S_2\left(T_0\right)}\exp (-\frac{\mathrm{hc}}{k_B}(E_1^{\&prime;\&prime;}-{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA0000083725040000012.png,HDA0000083725040000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_2^{\&prime;\&prime;})(\frac{1}{T}-\frac{1}{T_0}))$

Wherein: v ₀₁And v ₀₂Be respectively two centers that absorb line, h is the Planck constant, and c is the light velocity, k _BBe Boltzmann constant, T ₀Standard temperature 296K for the database use, S (T) is an absorption line strengths, and φ (v) is linear function, widens linear and pressure Lorentz lorentz's type is widened linear convolution and obtained by the Doppler of Gaussian, and linear function satisfies ∫ φ, and (v) dv=1, E " are attitude energy levels under the transition.Database HITRAN2008 discloses the absorption line center v of 29 kinds of main atmospheric molecules ₀, S (T) and E ".In database HITRAN2008, search and v ₀₁And v ₀₂Corresponding S (T ₀) and E ", calculate gas temperature value T further combined with the R that records.

Simultaneously, measured target gas absorptivity satisfy Beer-Lambert relational expression, T _v=I _v/ I ₀=exp (k _vL).

Wherein: T _vBe laser transmissivity through the L light path in medium, k _vBe absorptivity.

Absorptivity k _vBe under the pressure P, the concentration X of certain measured target gas _Gas, absorption line strengths S (T) and linear function φ (function v), and linear function satisfies ∫ φ (v) dv=1.Absorptivity k _vCan be expressed as: k _v=S (T) X _GasP φ (v).Above-mentioned two kinds of methods can Laser Measurement be passed through the transmissivity of L light path in medium, and then extrapolate absorptivity k _v, further according to absorptivity k _vComputing formula obtain the concentration of measured target gas.

Yet, above-mentioned two kinds of methods are when the concentration of the temperature of measuring measured target gas and measured target gas, need scan the optical maser wavelength in certain wavelength band and recording laser spectrum, therefore measuring speed is subjected to the laser modulation frequency limitation, and the response time of laser modulation frequency the fastest be 0.1ms, thereby reduced measuring speed, increased time loss.

Summary of the invention

In view of this, the embodiment of the present application discloses a kind of system and method that utilizes laser spectrum measurement gas parameter, to improve measuring speed, reduces time loss.Technical scheme is as follows:

The embodiment of the present application discloses a kind of system that utilizes laser spectrum measurement gas parameter, comprise: first locking channel, two sample measurement channel, first laser generator, second laser generator, signal generator, detector, receiving light path device, locking device and control device, wherein:

Described first laser generator and described second laser generator comprise laser power controller and laser delivery, described laser power controller is used to receive the signal that described signal generator produces, the laser signal that described laser delivery generates is modulated, and the laser signal after the modulation is sent by described laser delivery;

Described locking device, be used to receive the laser signal that described detector detects, the laser signal that detects is carried out demodulation according to the signal that described signal generator produces, generate feedback control signal, control the laser power controller of first laser generator, the absorption line center v of the Wavelength of Laser signal target molecule in described first locking channel target molecule sample cell of living in after the modulation of sending with the laser delivery that locks first laser generator ₀₁The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in first laser generator of the described receiving light path device and first locking channel sends;

Described control device, be used to gather the laser signal that described detector detects, the laser signal that collects is carried out analog to digital conversion, concentration according to analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is to enter the laser signal that the laser delivery in first laser generator of described receiving light path device and described sample measurement channel sends, and enters the laser signal that the laser delivery in second laser generator of described sample measurement channel sends.

Preferably, described receiving light path device comprises: first beam splitter and first catoptron; Laser signal after the modulation that described first beam splitter sends the laser delivery in described first laser generator is divided into reflected light signal and optical signal transmissive, wherein reflected light signal enters described sample measurement channel through described first mirror reflects, and optical signal transmissive enters described first locking channel.

Preferably, also comprise: second locking channel;

Described receiving light path device also comprises: second beam splitter and second catoptron; Laser signal after the modulation that described second beam splitter sends the laser delivery in described second laser generator is divided into reflected light signal and optical signal transmissive, wherein reflected light signal enters described second locking channel through described second mirror reflects, and optical signal transmissive enters described sample measurement channel.

Preferably, also comprise: the detector and the locking device that link to each other with described second locking channel;

This locking device, be used to receive the laser signal that described detector detects, the laser signal that detects is carried out demodulation according to the signal that described signal generator produces, generate feedback control signal, control the laser power controller of second laser generator, the absorption line center v of wavelength target molecule in described second locking channel target molecule sample cell of living in of the laser signal after the modulation of sending with the laser delivery that locks second laser generator ₀₂The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in second laser generator of the described receiving light path device and second locking channel sends;

Described control device, also be used to gather the laser signal that described detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is the laser signal that enters after the modulation of described receiving light path device and described sample measurement channel.

Preferably, also comprise: two reference channels;

Described receiving light path device also comprises: the 3rd beam splitter and the 4th beam splitter;

The reflected light signal of described first beam splitter is reflected light signal and optical signal transmissive through described the 3rd beam splitter beam splitting, and the reflected light signal of the 3rd beam splitter enters a reference channel, and the optical signal transmissive of the 3rd beam splitter is received by described first catoptron;

The reflected light signal of described second beam splitter is reflected light signal and optical signal transmissive through described the 4th beam splitter beam splitting, and the reflected light signal of the 4th beam splitter enters another reference channel, and the optical signal transmissive of the 4th beam splitter is received by described second catoptron.

Preferably, also comprise: the detector that links to each other with described reference channel respectively;

Described control device, also be used to gather the laser signal that described detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas and the concentration of measured target gas, wherein the laser signal that detects of detector is the laser signal that enters described receiving light path device and described reference channel, and the laser signal that enters described receiving light path device and described sample measurement channel.

Preferably, described locking device comprises: lock-in amplifier and proportion integration differentiation PID amplifier;

Described lock-in amplifier is used to receive the laser signal that described detector detects, and the laser signal that detects is carried out demodulation according to the signal that described signal generator produces, and the signal after the demodulation is sent;

Described PID amplifier, be used to receive the signal after the demodulation that described lock-in amplifier sends, signal after the described demodulation is carried out proportional integral to be amplified, generate feedback control signal, control described laser power controller, with the absorption line center of wavelength target molecule in described locking channel target molecule sample cell of living in of locking the laser signal after the modulation that described laser delivery sends.

The embodiment of the present application also discloses a kind of method of utilizing laser spectrum measurement gas parameter, comprising:

The signal that laser power controller received signal generator produces is modulated the laser signal that the laser delivery generates, and the laser signal after the modulation is sent by the laser delivery;

The laser signal that the locking device pick-up probe detects, the signal that the laser signal basis signal generator that detects is produced carries out demodulation, generate feedback control signal, control the laser power controller of first laser generator, the absorption line center v of wavelength target molecule in first locking channel target molecule sample cell of living in of the laser signal that sends with the laser delivery that locks first laser generator ₀₁The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in first laser generator of the receiving light path device and first locking channel sends;

Control device is gathered the laser signal that detector detects, the laser signal that collects is carried out analog to digital conversion, concentration according to analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is to enter the laser signal that the laser delivery in first laser generator of receiving light path device and sample measurement channel sends, and enters the laser signal that the laser delivery in second laser generator of sample measurement channel sends.

Preferably, also comprise:

The laser signal that the locking device pick-up probe detects, the signal that the laser signal basis signal generator that detects is produced carries out demodulation, generate feedback control signal, control the laser power controller of second laser generator, the absorption line center v of wavelength target molecule in second locking channel target molecule sample cell of living in of the laser signal that sends with the laser delivery that locks second laser generator ₀₂The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in second laser generator of the receiving light path device and second locking channel sends;

Control device is gathered the laser signal that detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is the laser signal that enters described receiving light path device and described sample measurement channel.

Preferably, described concentration according to analog to digital conversion outcome measurement measured target gas is specially:

Obtain laser signal that the laser delivery of first laser generator sends at the absorption peak H that absorbs the line center according to the analog to digital conversion result;

In conjunction with formula

Draw the concentration of measured target gas, wherein: H is an absorption peak, and P is the general pressure of all gas in the sample pond, L is the length of the light path of laser signal in the sample pond, φ (v) be linear function, and linear function satisfy ∫ φ (v) dv=1, S (T) is an absorption line strengths;

Temperature according to analog to digital conversion outcome measurement measured target gas is specially: obtain the laser signal that the laser delivery sends in first laser generator and second laser generator according to the analog to digital conversion result and absorb line center v at target molecule respectively ₀₁And v ₀₂The absorption peak at place compares R;

In conjunction with formula $R=k_{v,1}/k_{v,2}=\frac{S_1\left(T_0\right){\mathrm{\&phi;}}_1\left(v\right)}{S_2\left(T_0\right){\mathrm{\&phi;}}_2\left(v\right)}\exp (-\frac{\mathrm{hc}}{k_B}(E_1^{\&prime;\&prime;}-{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA0000083725040000012.png,HDA0000083725040000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_2^{\&prime;\&prime;})(\frac{1}{T}-\frac{1}{T_0}))$ Draw the temperature of measured target gas, wherein: h is the Planck constant, and c is the light velocity, k _BBe Boltzmann constant, T ₀Be the standard temperature 296K that database uses, E and " be attitude energy levels under the transition, S (T ₀) be absorption line strengths, φ (v) be linear function, and linear function satisfies ∫ φ (v) dv=1.

Use technique scheme, the absorption line center v of wavelength locking target molecule in first locking channel target molecule sample cell of living in of the laser signal after the modulation that locking device sends the laser delivery of first laser generator ₀₁The place, the laser signal that the laser delivery of first laser generator that enters receiving light path device and sample measurement channel that the control device collection is detected by detector sends, and the laser signal that sends of the laser delivery that enters second laser generator of sample measurement channel, the laser signal that collects is carried out analog to digital conversion, according to the concentration of analog to digital conversion outcome measurement measured target gas.The embodiment of the present application is disclosed utilizes the measuring speed of the system of laser spectrum measurement gas parameter to be subject to the data acquisition time of control device, and data acquisition time is minimum at present is microsecond, response time with respect to laser modulation frequency in the prior art improves greatly, thereby improved measuring speed, reduced time loss.

Description of drawings

In order to be illustrated more clearly in the embodiment of the present application or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, the accompanying drawing that describes below only is some embodiment that put down in writing among the application, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the disclosed a kind of structural representation that utilizes the system of laser spectrum measurement gas parameter of the embodiment of the present application;

Fig. 2 is the disclosed another kind of structural representation that utilizes the system of laser spectrum measurement gas parameter of the embodiment of the present application;

Fig. 3 is disclosed another structural representation that utilizes the system of laser spectrum measurement gas parameter of the embodiment of the present application;

The measured target gas temperature curve map that Fig. 4 measures for the embodiment of the present application;

The measured target gas temperature curve map that Fig. 5 measures for the scanning wavelength method;

The structural representation of locking device in the system that Fig. 6 utilizes laser spectrum measurement gas parameter for the embodiment of the present application is disclosed;

Fig. 7 is the disclosed a kind of process flow diagram that utilizes the method for laser spectrum measurement gas parameter of the embodiment of the present application;

Fig. 8 is the disclosed another kind of process flow diagram that utilizes the method for laser spectrum measurement gas parameter of the embodiment of the present application.

Embodiment

For above-mentioned purpose, the feature and advantage that make the application can become apparent more, the application is described in further detail below in conjunction with the drawings and specific embodiments.

An embodiment

See also Fig. 1, Fig. 1 is the disclosed system that utilizes laser spectrum measurement gas parameter of the embodiment of the present application, comprising: first locking channel 101, two sample measurement channel 102 and 103, first laser generator 104, second laser generator 105, signal generator 106, detector 107, detector 108, detector 109, receiving light path device 110, locking device 111 and control device 112.Wherein:

First locking channel 101 is arranged in target molecule sample cell 122, and as the water sample pond, the absorption line center of first locking channel 101 is an absorption line center v of target molecule in the target molecule sample cell ₀₁ Sample measurement channel 102 and 103 is arranged in same sample pond 123.

First laser generator 104 and second laser generator 105 comprise laser power controller and laser delivery respectively, laser power controller is used for the signal that received signal generator 106 produces, the laser signal that the laser delivery generates is modulated, and the laser signal after the modulation is sent by the laser delivery.

Laser signal after the modulation that the laser delivery of first laser generator 104 sends is divided into the two-way laser signal through receiving light path device 110, and one road laser signal enters first locking channel 101.The laser signal that detector 107 is surveyed in first locking channel 101 sends to locking device 111 with this laser signal.

The signal of locking device 111 received signal generator 106 generations simultaneously, the signal that basis signal generator 106 produces carries out demodulation to the laser signal that receives, and generates feedback control signal, controls the laser power controller of first laser generator 104.The laser power controller of first laser generator 104 is further according to this feedback control signal modulated laser delivery, the absorption line center v of wavelength target molecule in first locking channel, 101 target molecule sample cells of living in of the laser signal that sends with the laser delivery that locks first laser generator 104 ₀₁The place.

It is 50mV that above-mentioned signal generator 106 can produce an amplitude, modulating frequency is the sinusoidal signal of 13kHz, this sinusoidal signal is applied to the laser power controller of first laser generator 104 and second laser generator 105 respectively, the laser signal that the laser delivery generates is carried out Sine Modulated by laser power controller.Signal generator 106 can also produce cosine signal, by laser power controller the laser signal that the laser delivery generates is carried out cosine modulation.The amplitude that signal generator 106 produces signal is different according to the different application scene with modulating frequency, absorption line center difference as first locking channel in the different application scene, the absorption line center of first locking channel that signal generator 106 correspondences are different produces the signal with different amplitudes and modulating frequency.

First laser generator 104 is received another road laser signal that light path device 110 is divided into and enters sample measurement channel 102, surveyed by detector 108, and detector 108 sends to control device 112 with the laser signal that detects.The laser signal that the laser delivery of second laser generator 105 sends directly enters sample measurement channel 103, surveyed by detector 109, and detector 109 sends to control device 112 with the laser signal that detects.

Receiving light path device 110 comprises: first beam splitter 1101 and first catoptron 1102.Laser signal after the modulation that first beam splitter 1101 sends the laser delivery of described first laser generator 104 is divided into reflected light signal and optical signal transmissive, wherein 1102 reflections enter sample measurement channel 102 to reflected light signal through first catoptron, and optical signal transmissive enters first locking channel 101.

Control device 112 is gathered the laser signal that detector 108 and 109 detects respectively, and the laser signal that collects is carried out analog to digital conversion, according to the concentration of analog to digital conversion outcome measurement measured target gas.Be specially:

The analog to digital conversion result who supposes 112 pairs of detectors that collect 108 of control device and 109 laser signals that detected is respectively I ₁And I ₂, because the absorption line center v of wavelength locking target molecule in first locking channel, 101 target molecule sample cells of living in of the laser signal after the modulation that the laser delivery of first laser generator 104 sends ₀₁The place, and the laser signal wavelength that the laser delivery of second laser generator 105 sends is placed in and absorbs outside the line, so the laser signal wavelength place that the ratio of two transformation results is the laser delivery of first laser generator 104 to be sent (is the absorption line center v of target molecule ₀₁The place) absorption peak H, i.e. the absorption line center v of target molecule ₀₁The absorption peak H at place is H=I ₁/ I ₂

After obtaining absorption peak H, in conjunction with formula

Draw the concentration of measured target gas, wherein: H is an absorption peak, L is the length of the light path of laser signal in sample pond 123, can directly measure, φ (v) is linear function, widens linear and pressure Lorentz lorentz's type is widened linear convolution and obtained by the Doppler of Gaussian, and linear function satisfies ∫ φ (v) dv=1, S (T) is an absorption line strengths, and P is the general pressure of all gas in the sample pond 123, can measure by pressure transducer.Database HITRAN2008 discloses the center v of the absorption line of 29 kinds of main atmospheric molecules ₀, S (T ₀) and E ", wherein: T ₀Standard temperature 296K for database uses can search S (T), and then know the concentration of measured target gas in this database.

Use technique scheme, the absorption line center v of wavelength locking target molecule in first locking channel, 101 target molecule sample cells of living in of the laser signal after the modulation that locking device 111 sends the laser delivery of first laser generator 104 ₀₁The place, laser signal after the modulation that the laser delivery that control device 112 is gathered first laser generator 104 that enters receiving light path device 110 and sample measurement channel 102 that is detected by detector sends, and the laser signal after the laser delivery that enters second laser generator 105 of sample measurement channel 103 modulation of sending, the laser signal that collects is carried out analog to digital conversion, according to the concentration of analog to digital conversion outcome measurement measured target gas.

The inventor goes out the data acquisition time that the disclosed measuring speed that utilizes the system of laser spectrum measurement gas parameter of the embodiment of the present application only is subject to control device 112 through experimental summary repeatedly, and data acquisition time is minimum at present is microsecond, response time with respect to laser modulation frequency in the prior art improves greatly, thereby improved measuring speed, reduced time loss.

Another embodiment

Said system embodiment can measure the concentration at measured target gas, and the temperature of measured target gas is as the important parameter of measured target gas, its measurement is helped the researchist natural environment and climate is analyzed.The embodiment of the present application also discloses the another kind of system that utilizes laser spectrum measurement gas parameter, and the temperature of measured target gas can be measured by this system, further measures the concentration of measured target gas under the different temperatures.

See also Fig. 2, Fig. 2 is the disclosed another kind of structural representation that utilizes the system of laser spectrum measurement gas parameter of the embodiment of the present application, based on Fig. 1, the detector 114 and the locking device 115 that increased by second locking channel 113, link to each other with second locking channel 113.Wherein:

Second locking channel 113 and first locking channel 101 are arranged in same target molecule sample cell 122, and the absorption line center of second locking channel 113 is another absorption line center v of target molecule in the target molecule sample cell 122 ₀₂

Locking device 115 is used for the laser signal that pick-up probe 114 detects, and the signal that the laser signal basis signal generator 106 that detects is produced carries out demodulation, generates feedback control signal, controls the laser power controller of second laser generator 105.The laser power controller of second laser generator 105 is further according to this feedback control signal modulated laser delivery, the absorption line center v of wavelength target molecule in second locking channel, 113 target molecule sample cells of living in of the laser signal after the modulation of sending with locking laser delivery ₀₂The place, wherein the laser signal that detects of detector 114 is the laser signal that enters after the modulation that the laser delivery of second laser generator 105 of the receiving light path device 110 and second locking channel 113 sends.

Further, control device 112 is gathered the laser signal that detector 108 and 109 detects respectively, and the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas.Wherein: the laser signal that detector 108 detects enters the laser signal of receiving light path device 110 and sample measurement channel 102 for the laser delivery by first laser generator 104 sends.The laser signal that detector 109 detects is that the laser delivery of second laser generator 105 sends, and enters the laser signal of receiving light path device 110 and sample measurement channel 103.

Control device 112 is specially according to the temperature of analog to digital conversion outcome measurement measured target gas:

The analog to digital conversion result who supposes 112 pairs of detectors that collect 108 of control device and 109 laser signals that detected is respectively I ₃And I ₄, because the wavelength of the laser signal after the modulation that the laser delivery of first laser generator 104 and second laser generator 105 sends is locked in the absorption line center v of target molecule in first locking channel 101 and second locking channel, the 113 target molecule sample cells of living in respectively ₀₁And v ₀₂The place is absorbing line center v so the ratio of two transformation results is target molecule ₀₁And v ₀₂The absorption peak at place is than R, and promptly absorption peak is R=I than R ₃/ I ₄

After the acquisition absorption peak is than R, in conjunction with formula $R=k_{v,1}/k_{v,2}=\frac{S_1\left(T_0\right){\mathrm{\&phi;}}_1\left(v\right)}{S_2\left(T_0\right){\mathrm{\&phi;}}_2\left(v\right)}\exp (-\frac{\mathrm{hc}}{k_B}(E_1^{\&prime;\&prime;}-{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA0000083725040000012.png,HDA0000083725040000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_2^{\&prime;\&prime;})(\frac{1}{T}-\frac{1}{T_0}))$ Draw the temperature of measured target gas, wherein: h is the Planck constant, and c is the light velocity, k _BBe Boltzmann constant, T ₀Be the standard temperature 296K that database uses, E and " be attitude energy levels under the transition, S (T ₀) be absorption line strengths, φ (v) is linear function, widens linear and pressure Lorentz lorentz's type is widened linear convolution and obtained by the Doppler of Gaussian, and linear function satisfies ∫ φ (v) dv=1.

Control device 112 records the temperature of measured target gas as current gas temperature.After recording current gas temperature, operating personnel can operate two locking devices, control the laser power controller of any one laser generator, make laser signal after the modulation that the laser delivery sends be locked in the absorption line center v of its locking channel that enters ₀₁The place, the laser signal that the laser delivery of another laser generator sends places target molecule to absorb outside the line.112 concentration that can further measure the measured target gas under the current gas temperature of control device, detailed process sees also an embodiment.

Above-mentioned receiving light path device 110 also comprises on Fig. 1 basis: second beam splitter 1103 and second catoptron 1104.Laser signal after the modulation that second beam splitter 1103 sends the laser delivery of second laser generator 105 is divided into reflected light signal and optical signal transmissive, wherein 1104 reflections enter second locking channel 113 to reflected light signal through second catoptron, and optical signal transmissive enters sample measurement channel 103.From the system that utilizes laser spectrum measurement gas parameter shown in Figure 2 as can be seen: the laser signal after the modulation that the laser delivery of above-mentioned first laser generator 104 and second laser generator 105 sends all is received light path device 110 and is divided into two-way, enters different passages respectively and is surveyed by different detectors.

Use technique scheme, can realize measurement the concentration of measured target gas under the temperature of measured target gas and this temperature.Simultaneously, the inventor is through repeatedly experiment discovery, the embodiment of the present application is disclosed utilizes the measuring speed of the system of laser spectrum measurement gas parameter still only to be subject to the data acquisition time of control device 112, and data acquisition time is minimum at present is microsecond, response time with respect to laser modulation frequency in the prior art improves greatly, thereby improved measuring speed, reduced time loss.

Another embodiment

Above-mentioned two system embodiments are not considered the influence of the laser signal after the modulation that Atmospheric Absorption in the sample pond sends the laser delivery when the temperature of the concentration of measuring measured target gas and measured target gas, reduce measuring accuracy.For fear of above-mentioned influence, the embodiment of the present application also discloses the another kind of system that utilizes laser spectrum measurement gas parameter, and structural representation sees also Fig. 3.

Fig. 3 is disclosed another structural representation that utilizes the system of laser spectrum measurement gas parameter of the embodiment of the present application, based on Fig. 2, increases by two reference channels 116 and 117, detector 118 and 119.Wherein:

Receiving light path device 110 also comprises: the 3rd beam splitter 1105 and the 4th beam splitter 1106.1105 beam splitting are reflected light signal and optical signal transmissive to the reflected light signal of first beam splitter 1101 through the 3rd beam splitter, the optical signal transmissive that the reflected light signal of the 3rd beam splitter 1105 enters reference channel 116, the three beam splitters 1105 is received by first catoptron 1102.

1106 beam splitting are reflected light signal and optical signal transmissive to the reflected light signal of second beam splitter 1103 through the 4th beam splitter, the optical signal transmissive that the reflected light signal of the 4th beam splitter 1106 enters reference channel 117, the four beam splitters 1106 is received by second catoptron 1104.

Above-mentioned reference channel 116 and 117 is arranged in atmosphere, and the signal that enters reference channel 116 and 117 is detected device 118 and 119 respectively and surveys.Further, control device 112, gather detector 108,109,118 and 119 laser signals that detect, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas and the concentration of measured target gas, wherein the laser signal that detects of detector 118 is the laser signal that enters receiving light path device 110 and reference channel 116, the laser signal that detector 119 detects is the laser signal that enters receiving light path device 110 and reference channel 117, the laser signal that detector 108 detects is the laser signal that enters receiving light path device 110 and sample measurement channel 102, and the laser signal that detector 109 detects is the laser signal that enters receiving light path device 110 and sample measurement channel 103.

When measuring the measured target gas temperature, the wavelength of the laser signal after the modulation that the laser delivery of first laser generator 104 and second laser generator 105 sends is locked in the absorption line center v of first locking channel 101 and second locking channel, 113 target molecule sample cell target molecules of living in respectively ₀₁And v ₀₂The place.Temperature according to analog to digital conversion outcome measurement measured target gas is specially:

The analog to digital conversion result who supposes control device 112 pairs of detectors that collect 108,109,118 and 119 laser signals that detected is respectively I ₅, I ₆, I ₇And I ₈, the ratio of transformation result be the laser signal that sends of the laser delivery of first laser generator 104 and second laser generator 105 at the absorption peak that absorbs the line center than R, promptly absorption peak is R=(I than R ₅/ I ₇)/(I ₆/ I ₈).

After the acquisition absorption peak is than R, in conjunction with formula $R=k_{v,1}/k_{v,2}=\frac{S_1\left(T_0\right){\mathrm{\&phi;}}_1\left(v\right)}{S_2\left(T_0\right){\mathrm{\&phi;}}_2\left(v\right)}\exp (-\frac{\mathrm{hc}}{k_B}(E_1^{\&prime;\&prime;}-{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA0000083725040000012.png,HDA0000083725040000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_2^{\&prime;\&prime;})(\frac{1}{T}-\frac{1}{T_0}))$ Draw the temperature of gas, wherein: h is the Planck constant, and c is the light velocity, k _BBe Boltzmann constant, T ₀Be the standard temperature 296K that database uses, E and " be attitude energy levels under the transition, S (T ₀) be absorption line strengths, φ (v) is linear function, widens linear and pressure Lorentz lorentz's type is widened linear convolution and obtained by the Doppler of Gaussian, and linear function satisfies ∫ φ (v) dv=1.

Above-mentioned when obtaining absorption peak than R, control device 112 can be gathered the laser signal in two sample measurement channel and the reference channel simultaneously, and the laser signal in the reference channel is used for correcting sample and measures in the passage Atmospheric Absorption to the influence of laser signal, therefore the above-mentioned method of obtaining peakedness ratio R has improved peakedness ratio R precision, further improves overall measurement accuracy.

When measuring the concentration of measured target gas, the Wavelength of Laser after the modulation that the laser delivery of first laser generator 104 sends is locked in the absorption line center v of target molecule in first locking channel, the 101 target molecule sample cells of living in ₀₁The place.Concentration according to analog to digital conversion outcome measurement measured target gas is specially:

The analog to digital conversion result who supposes control device 112 pairs of detectors that collect 108,109,118 and 119 laser that detected is respectively I ₅, I ₆, I ₇And I ₈, the ratio of transformation result is that the laser after the modulation of sending of the laser delivery of first laser generator 104 is absorbing line center v ₀₁The peak value H at place, promptly the laser that sends of the laser delivery of first laser generator 104 is H=(I at the absorption peak H that absorbs the line center ₅/ I ₇)/(I ₆/ I ₈).

After obtaining absorption peak H, in conjunction with formula

Draw the concentration of measured target gas, wherein: H is an absorption peak, P is the general pressure of all gas in the sample pond 123, L is the length of the light path of laser signal in sample pond 123, can directly measure, φ (v) is linear function, widens linear and pressure Lorentz lorentz's type is widened linear convolution and obtained by the Doppler of Gaussian, and linear function satisfies ∫ φ, and (v) dv=1, S (T) is an absorption line strengths.

The curve map of the measured target gas temperature that the foundation system that utilizes laser spectrum measurement gas parameter shown in Figure 3 measures as shown in Figure 4.The gas temperature curve map that Fig. 5 measures for the scanning wavelength method, wherein: the horizontal ordinate of Fig. 5 is an experiment number.Fig. 4 and Fig. 5 are for selecting two centers to lay respectively at the absorption line of 1365.03nm and 1397.08nm according to HITRAN2008, and pressure P is to record under 9600Pa, the normal temperature.Adopting semiconductor thermometer monitoring gas temperature simultaneously is 295 ± 1K.

Draw from above-mentioned two curve maps, the measured target gas temperature that the embodiment of the present application is disclosed utilizes the system of laser spectrum measurement gas parameter to measure is 296 ± 1K, and measuring speed is 400kHz, and the single-point response time is 2.5 μ s.The measured target gas temperature that the scanning wavelength method is measured is at 1-10Hz low speed accuracy of measurement height, and when the 100Hz velocity survey, accuracy of measurement is low.

Need to prove: the temperature survey uncertainty of scanning wavelength method is:

And the temperature survey inaccuracy of the application system is: Utilize the integration absorptance of experiment measuring and the relative error of peak height absorptance

Can extrapolate the measuring error that adopts different measuring method temperature.Clearly, when adopting the application to measure temperature, two linear functions compare relative error

Also can cause the temperature survey deviation.Therefore the application is more strict to absorbing the right selection of line, and need meet the following conditions: it is comparatively isolated to absorb line; Absorptivity is not less than 5%; Article two, the following attitude energy level difference that absorbs line is enough big; Article two, the self collision that absorbs line is widened coefficient gamma _Self, air collision widens coefficient gamma _AirAnd temperature dependent coefficient n _AirApproximate identical; Absorb the air pressure displacement δ of line _AirAs far as possible little.

Use technique scheme, avoided the influence of the laser signal after the modulation that the 123 pairs of laser deliveries in sample measurement channel sample of living in pond send, improve measuring accuracy.

Above-mentioned Fig. 1 is to the system that utilizes laser spectrum measurement gas parameter shown in Figure 3, locking device 111 and 115 structural representation are as shown in Figure 6, comprise: lock-in amplifier 120 and PID (Proportion Integration Differentiation, proportion integration differentiation) amplifier 121;

Lock-in amplifier 120 is used for the laser signal that pick-up probe detects, and the signal that the laser signal basis signal generator 106 that detects is produced carries out demodulation, and the signal after the demodulation is sent.The laser signal that lock-in amplifier 120 pick-up probes 107 in the locking device 111 detect, the laser signal that lock-in amplifier 120 pick-up probes 114 in the locking device 115 detect.

PID amplifier 121, be used to receive the signal after the demodulation that lock-in amplifier 120 sends, signal after the demodulation is carried out proportional integral to be amplified, generate feedback control signal, the control laser power controller, the absorption line center of wavelength target molecule in locking channel target molecule sample cell of living in of the laser signal after the modulation of sending with locking laser delivery.

Above-mentioned Fig. 1 laser delivery to the system that utilizes laser spectrum measurement gas parameter shown in Figure 3 is the semiconductor diode laser delivery, and detector is the InGaAs infrared eye that bandwidth is 10MHz.

Embodiment is corresponding with said system, and the embodiment of the present application also discloses a kind of method of utilizing laser spectrum measurement gas parameter, and process flow diagram comprises as shown in Figure 7:

S101: the signal that laser power controller received signal generator produces, the laser signal that the laser delivery generates to be modulated, the laser signal after the modulation is sent by the laser delivery.

S102: the laser signal that the locking device pick-up probe detects, the signal that the laser signal basis signal generator that detects is produced carries out demodulation, generate feedback control signal, control the laser power controller in first laser generator, the absorption line center v of wavelength target molecule in first locking channel target molecule sample cell of living in of the laser signal after the modulation of sending with locking laser delivery ₀₁The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in first laser generator of the receiving light path device and first locking channel sends;

S103: control device is gathered the laser signal that detector detects, the laser signal that collects is carried out analog to digital conversion, concentration according to analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is to enter the laser signal that the laser delivery in first laser generator of receiving light path device and sample measurement channel sends, and enters the laser signal that the laser delivery in second laser generator of sample measurement channel sends.

The method of utilizing laser spectrum measurement gas parameter shown in Figure 8, on Fig. 7 basis, realize the measured target gas thermometry is also comprised:

S104: the laser signal that the locking device pick-up probe detects, the signal that the laser signal basis signal generator that detects is produced carries out demodulation, generate feedback control signal, control the laser power controller in second laser generator, the absorption line center v of wavelength target molecule in described second locking channel target molecule sample cell of living in of the laser signal after the modulation of sending with locking laser delivery ₀₂The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in second laser generator of the receiving light path device and second locking channel sends;

S105: control device is gathered the laser signal that detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is the laser signal that enters described receiving light path device and described sample measurement channel.

Wherein: the concentration according to analog to digital conversion outcome measurement measured target gas is specially:

Obtain the laser delivery sends in first laser generator laser signal absorbs the line center at target molecule absorption peak according to the analog to digital conversion result;

In conjunction with formula

Draw the concentration of measured target gas, wherein: H is an absorption peak, P is the general pressure of all gas in the sample pond 123, can measure by pressure transducer, L is the length of the light path of laser signal in sample pond 123, can directly measure, (v) be linear function, S (T) is an absorption line strengths to φ.

Temperature according to analog to digital conversion outcome measurement measured target gas is specially: the laser signal that obtains after the laser delivery sends in first laser generator and second laser generator the modulation according to the analog to digital conversion result absorbs line center v two of target molecules respectively ₀₁And v ₀₂The absorption peak ratio at place;

In conjunction with formula $R=k_{v,1}/k_{v,2}=\frac{S_1\left(T_0\right){\mathrm{\&phi;}}_1\left(v\right)}{S_2\left(T_0\right){\mathrm{\&phi;}}_2\left(v\right)}\exp (-\frac{\mathrm{hc}}{k_B}(E_1^{\&prime;\&prime;}-{\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="HDA0000083725040000012.png,HDA0000083725040000021.png"\; state="\{\{state\}\}">E</figure-callout>}}_2^{\&prime;\&prime;})(\frac{1}{T}-\frac{1}{T_0}))$ Draw the temperature of measured target gas, wherein: h is the Planck constant, and c is the light velocity, k _BBe Boltzmann constant, T ₀Be the standard temperature 296K that database uses, E and " be attitude energy levels under the transition, S (T ₀) be absorption line strengths, φ (v) is the function of linear function, widens linear and pressure Lorentz lorentz's type is widened linear convolution and obtained by the Doppler of Gaussian, and linear function satisfies ∫ φ (v) dv=1.

The concrete enforcement of the step of said method embodiment sees also the related description in the system embodiment, and this is no longer set forth.

Each embodiment in this instructions all adopts the mode of going forward one by one to describe, identical similar part is mutually referring to getting final product between each embodiment, each embodiment stresses all is difference with other embodiment, those of ordinary skills promptly can understand and implement under the situation of not paying creative work.

The above only is the application's a embodiment; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the application's principle; can also make some improvements and modifications, these improvements and modifications also should be considered as the application's protection domain.

Claims (10)

1. system that utilizes laser spectrum measurement gas parameter, it is characterized in that, comprise: first locking channel, two sample measurement channel, first laser generator, second laser generator, signal generator, detector, receiving light path device, locking device and control device, wherein:

Described first laser generator and described second laser generator comprise laser power controller and laser delivery, described laser power controller is used to receive the signal that described signal generator produces, the laser signal that described laser delivery generates is modulated, and the laser signal after the modulation is sent by described laser delivery;

Described locking device, be used to receive the laser signal that described detector detects, the laser signal that detects is carried out demodulation according to the signal that described signal generator produces, generate feedback control signal, control the laser power controller of first laser generator, the absorption line center v of the Wavelength of Laser signal target molecule in described first locking channel target molecule sample cell of living in after the modulation of sending with the laser delivery that locks first laser generator ₀₁The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in first laser generator of the described receiving light path device and first locking channel sends;

Described control device, be used to gather the laser signal that described detector detects, the laser signal that collects is carried out analog to digital conversion, concentration according to analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is to enter the laser signal that the laser delivery in first laser generator of described receiving light path device and described sample measurement channel sends, and enters the laser signal that the laser delivery in second laser generator of described sample measurement channel sends.

2. the system that utilizes laser spectrum measurement gas parameter according to claim 1 is characterized in that, described receiving light path device comprises: first beam splitter and first catoptron; Laser signal after the modulation that described first beam splitter sends the laser delivery in described first laser generator is divided into reflected light signal and optical signal transmissive, wherein reflected light signal enters described sample measurement channel through described first mirror reflects, and optical signal transmissive enters described first locking channel.

3. the system that utilizes laser spectrum measurement gas parameter according to claim 2 is characterized in that, also comprises: second locking channel;

Described receiving light path device also comprises: second beam splitter and second catoptron; Laser signal after the modulation that described second beam splitter sends the laser delivery in described second laser generator is divided into reflected light signal and optical signal transmissive, wherein reflected light signal enters described second locking channel through described second mirror reflects, and optical signal transmissive enters described sample measurement channel.

4. the system that utilizes laser spectrum measurement gas parameter according to claim 3 is characterized in that, also comprises: the detector and the locking device that link to each other with described second locking channel;

This locking device, be used to receive the laser signal that described detector detects, the laser signal that detects is carried out demodulation according to the signal that described signal generator produces, generate feedback control signal, control the laser power controller of second laser generator, the absorption line center v of wavelength target molecule in described second locking channel target molecule sample cell of living in of the laser signal after the modulation of sending with the laser delivery that locks second laser generator ₀₂The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in second laser generator of the described receiving light path device and second locking channel sends;

Described control device, also be used to gather the laser signal that described detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is the laser signal that enters after the modulation of described receiving light path device and described sample measurement channel.

5. the system that utilizes laser spectrum measurement gas parameter according to claim 4 is characterized in that, also comprises: two reference channels;

Described receiving light path device also comprises: the 3rd beam splitter and the 4th beam splitter;

The reflected light signal of described first beam splitter is reflected light signal and optical signal transmissive through described the 3rd beam splitter beam splitting, and the reflected light signal of the 3rd beam splitter enters a reference channel, and the optical signal transmissive of the 3rd beam splitter is received by described first catoptron;

The reflected light signal of described second beam splitter is reflected light signal and optical signal transmissive through described the 4th beam splitter beam splitting, and the reflected light signal of the 4th beam splitter enters another reference channel, and the optical signal transmissive of the 4th beam splitter is received by described second catoptron.

6. the system that utilizes laser spectrum measurement gas parameter according to claim 5 is characterized in that, also comprises: the detector that links to each other with described reference channel respectively;

Described control device, also be used to gather the laser signal that described detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas and the concentration of measured target gas, wherein the laser signal that detects of detector is the laser signal that enters described receiving light path device and described reference channel, and the laser signal that enters described receiving light path device and described sample measurement channel.

7. according to any described system that utilizes laser spectrum measurement gas parameter of claim 1 to 6, it is characterized in that described locking device comprises: lock-in amplifier and proportion integration differentiation PID amplifier;

Described lock-in amplifier is used to receive the laser signal that described detector detects, and the laser signal that detects is carried out demodulation according to the signal that described signal generator produces, and the signal after the demodulation is sent;

Described PID amplifier, be used to receive the signal after the demodulation that described lock-in amplifier sends, signal after the described demodulation is carried out proportional integral to be amplified, generate feedback control signal, control described laser power controller, with the absorption line center of wavelength target molecule in described locking channel target molecule sample cell of living in of locking the laser signal after the modulation that described laser delivery sends.

8. a method of utilizing laser spectrum measurement gas parameter is characterized in that, comprising:

The signal that laser power controller received signal generator produces is modulated the laser signal that the laser delivery generates, and the laser signal after the modulation is sent by the laser delivery;

The laser signal that the locking device pick-up probe detects, the signal that the laser signal basis signal generator that detects is produced carries out demodulation, generate feedback control signal, control the laser power controller of first laser generator, the absorption line center v of wavelength target molecule in first locking channel target molecule sample cell of living in of the laser signal that sends with the laser delivery that locks first laser generator ₀₁The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in first laser generator of the receiving light path device and first locking channel sends;

Control device is gathered the laser signal that detector detects, the laser signal that collects is carried out analog to digital conversion, concentration according to analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is to enter the laser signal that the laser delivery in first laser generator of receiving light path device and sample measurement channel sends, and enters the laser signal that the laser delivery in second laser generator of sample measurement channel sends.

9. the method for utilizing laser spectrum measurement gas parameter according to claim 8 is characterized in that, also comprises:

The laser signal that the locking device pick-up probe detects, the signal that the laser signal basis signal generator that detects is produced carries out demodulation, generate feedback control signal, control the laser power controller of second laser generator, the absorption line center v of wavelength target molecule in second locking channel target molecule sample cell of living in of the laser signal that sends with the laser delivery that locks second laser generator ₀₂The place, wherein the laser signal that detects of detector is to enter the laser signal that the laser delivery in second laser generator of the receiving light path device and second locking channel sends;

Control device is gathered the laser signal that detector detects, the laser signal that collects is carried out analog to digital conversion, according to the temperature of analog to digital conversion outcome measurement measured target gas, the laser signal that detector detects is the laser signal that enters described receiving light path device and described sample measurement channel.

10. the method for utilizing laser spectrum measurement gas parameter according to claim 9 is characterized in that, described concentration according to analog to digital conversion outcome measurement measured target gas is specially:

Obtain laser signal that the laser delivery of first laser generator sends at the absorption peak H that absorbs the line center according to the analog to digital conversion result;

In conjunction with formula

Draw the concentration of measured target gas, wherein: H is an absorption peak, and P is the general pressure of all gas in the sample pond, L is the length of the light path of laser signal in the sample pond, φ (v) be linear function, and linear function satisfy ∫ φ (v) dv=1, S (T) is an absorption line strengths;

Temperature according to analog to digital conversion outcome measurement measured target gas is specially: obtain the laser signal that the laser delivery sends in first laser generator and second laser generator according to the analog to digital conversion result and absorb line center v at target molecule respectively ₀₁And v ₀₂The absorption peak at place compares R;

In conjunction with formula $R=k_{v,1}/k_{v,2}=\frac{S_1\left(T_0\right){\mathrm{\&phi;}}_1\left(v\right)}{S_2\left(T_0\right){\mathrm{\&phi;}}_2\left(v\right)}\exp (-\frac{\mathrm{hc}}{k_B}(E_1^{\&prime;\&prime;}-E_2^{\&prime;\&prime;})(\frac{1}{T}-\frac{1}{T_0}))$ Draw the temperature of measured target gas, wherein: h is the Planck constant, and c is the light velocity, k _BBe Boltzmann constant, T ₀Be the standard temperature 296K that database uses, E and " be attitude energy levels under the transition, S (T ₀) be absorption line strengths, φ (v) be linear function, and linear function satisfies ∫ φ (v) dv=1.

Images