CN201163269Y - Laser absorptive spectrum trace amount gas analyzer - Google Patents

Abstract

The utility model relates to a device for analyzing gas trace of laser absorption spectrum, comprising a measuring air chamber, wherein, a laser emitting device and a laser receiving device are respectively arranged on both ends of the measuring air chamber; the laser receiving device is connected with a signal processing display unit; a cylindrical calibrating air chamber is also arranged inside the measuring air chamber; the end part of the calibrating air chamber is provided with a calibrating laser emitting device and a calibrating laser receiving device; the calibrating laser emitting device is connected to a light path of the laser emitting device; the calibrating laser receiving device is connected to the signal processing display unit; and a pressure balance structure for balancing internal pressure and external pressure of the air chamber is also arranged on the calibrating air chamber. By utilization of the device for measuring trace gas, the measurement of the trace gas is simple and accurate; the structure is greatly simplified; and real-time self-calibration can be realized.

Description

The laser absorption spectrum trace amount gas analytical equipment

Technical field

The utility model belongs to Industrial Engineering control and gas parameter analysis field; Be specifically related to a kind of self-alignment laser absorption spectrum trace amount gas parameter analytical equipment.

Background technology

The parameter analysis of emission gases is an important step of Industrial Engineering control; Such as production fields such as the burning control of waste incineration, thermal power generation, petrochemical industry, metallurgy, cement, the parameter measurement of emission gases is optimization production and the gordian technique that cuts down the consumption of energy especially.Traditional measuring method need be extracted a part of gas out from working environment, utilize physics and chemistry to purify, purify, analyze; Process complexity, measurement cost height, real-time is bad.The semi-conductor laser absorption spectrum technology is a kind of emerging gas measuring method, owing to advantages such as it have sensitive height, and selectivity is good, the response time is fast, is widely used in fields such as environment measuring, atmospheric science, trace analysis; It is the most promising a kind of technology in industrial process trace gas analysis field.

The ultimate principle of semi-conductor laser absorption spectrum technology is the absorption of being excited of gas; Beam of laser is passed tested gas, and when certain absorption line centre frequency of wavelength and tested gas of laser instrument was identical, gas molecule (atom) can absorb photon and transit to high level; Showing, is exactly the energy attenuation of laser.The energy attenuation of laser can be described by the Beer-Lambert law:

I _v＝I _v，0exp[-S(T)g(v-v′ ₀)PρL] (1)

Wherein, I _{V, 0}And I _vRepresent that respectively frequency is the light intensity of the laser of v by absorption gas front and back, S (T) expression gas absorption spectrum line line strength in the time of temperature T, g (v-v ' ₀) be the linear function of this absorption line of gas, P is an air pressure, and ρ is a gas concentration, and L is work light path (laser passes the length of gas).At pressure P, the light path L of known gas, work temperature, line strength S (T), linear function g (v-v ' ₀) under the situation, measure I _{V, 0}And I _vValue can be calculated the concentration of gas.Because the absorption line of gas is by the gas atom structures shape, the absorption line difference of gas with various; Therefore theoretically, other gases do not influence measuring in the working environment.

Tunable laser diodes absorption spectrum gas analysis instrument is the modal gas analysis instrument that adopts the semi-conductor laser absorption spectrum technology.Referring to accompanying drawing 1, (0～t in a work period ₀Constantly), its course of work is as follows: at first guarantee laser works temperature T on certain specific working point ₀(accompanying drawing 1a) guarantees the initialization wavelength X of laser instrument _Min(accompanying drawing 1c); Change the working current i (accompanying drawing 1b) of laser diode then, make it from i _MinBe increased to i _Max, the laser diode operation wavelength is by λ _MinTo λ _MaxLinear change (accompanying drawing 1c); When wavelength is not in tested gas absorption scope spectral line, be not excited absorbing phenomenon, the laser intensity of this moment can be used as I _{V, 0}(accompanying drawing 1d) when length scanning during by tested gas absorption scope spectral line, will be absorbed decay, and the light intensity of this moment is then as I _v, length scanning will obtain two light intensity parameters after once, it measures the pressure P and the work temperature of gas with adding sensing again, add line strength S (T) and linear function g (v-v ' ₀) scheduling theory value and known work light path L just can calculate tested gas concentration.Obviously, the accuracy of measurement depend on P, T, S (T), g (v-v ' ₀), the isoparametric accuracy of L, so actual surveying instrument all needs to utilize the gas of normal concentration to demarcate.There are the following problems for this method:

1, demarcate difficulty, be difficult to guarantee high measurement accuracy

By formula (1) as seen, the factor that influences measuring accuracy is very many, and wherein the measuring accuracy of P, T is limited by the precision and the point position of sensor, S (T) and g (v-v ' ₀) precision be limited by the precision of international standard HITRAN database itself.Studies show that for some gas, the error of HITRAN database may reach 2%～5%, this problem has had a strong impact on the application of this method in high-acruracy survey.

Usually adopt the method for periodic calibrating to improve measuring accuracy.One, equipment need leave the working site and regularly send producer's demarcation back to, and is very inconvenient; Two, demarcate and also just under normal temperature, normal pressure, carry out, can not contain all working temperatures and pressure, demarcation accuracy of (particularly in the high temperature and high pressure situation) under different temperatures and pressure also can not get guaranteeing like this.

2, need the accurate working temperature of measuring and controlling laser diode

In the tunable laser diodes absorption spectrum gas analysis instrument, the operation wavelength of the corresponding laser diode of the horizontal ordinate of absorption spectrum (wavelength or frequency), the ordinate correspondence be the light intensity of laser.The absorption line of common tested gas is very many, determine to record the sequence number of spectral line, and the wavelength of laser diode has played the effect of a wavelength standard; Promptly measure (referring to accompanying drawing 1d) after the absorption spectra, the wavelength that must record laser diode simultaneously could be determined spectral line sequence number (referring to accompanying drawing 1c), so according to theoretical value obtain corresponding S (T) and g (v-v ' ₀) two parameters.Because the restriction of cost can not be provided with an accurate wavemeter in the instrument; Can only calculate wavelength with the working temperature and the working current of laser diode; For laser diode, temperature is very big to the influence of wavelength, therefore, obtain optical maser wavelength information accurately, need do the requirement of high-precision temperature survey (requiring usually to reach 0.0001 ℃).In addition, the intensity difference of every absorption line of gas, accompanying drawing 2 and accompanying drawing 3 are near certain gas absorption spectra line charts 1580nm, ordinate among the figure is logarithmic coordinate, represent spectral line absorption intensity S (T) under the normal temperature, the adjacent spectral line R45 of the 0.1nm of as seen being separated by and the intensity of P5 can differ to 5 orders of magnitude; The absorption line (see accompanying drawing 2) of while in order to avoid other interference gas, in actual measurement, need guarantee that laser diode is in specific temperature working point, to guarantee that its wavelength is in certain specific scope, and then guarantee when changing laser works electric current realization length scanning, can inswept sequence number to be the spectral line of P5; Therefore this method needs accurately control laser diode working temperature, requires to reach 0.001 ℃ repeatability and 0.01 ℃ control accuracy usually.High like this temperature survey and control requirement have increased the difficulty and the manufacturing cost of instrument greatly.

3, complex structure

For surveying work gas temperature and pressure, need in the whole instrument system unnecessary temperature and pressure sensor is set, in circuit, also control corresponding and disposal system to be set; Add above-mentioned laser temperature measurement and control device, it is quite complicated that the structure of whole instrument seems, reduced reliability.

The utility model content

A purpose of the present utility model provides a kind of laser absorption spectrum trace amount gas analytical equipment that adopts this method for the deficiency that solves above-mentioned prior art existence just.Simple, accurate with its measurement of this measurement device trace gas, structure is also simplified greatly.

The purpose of this utility model adopts following proposal to realize:

The device of a kind of laser absorption spectrum gas trace analysis, comprise the measurement air chamber, be respectively equipped with laser beam emitting device and laser receiver at measurement air chamber two ends, described laser receiver is connected with the signal Processing display device, in described measurement air chamber, also be provided with a tubular calibration gas chamber, this calibration gas chamber end has calibration laser emitter and calibration laser receiving trap, described calibration laser emitter is connected in the light path of described laser beam emitting device, described calibration laser receiving trap is connected in the signal Processing display device, also is provided with the pressure balancing structure of balance air chamber external and internal pressure on the described calibration gas chamber.

Described pressure balancing structure is a pressure diaphragm capsule, and this pressure diaphragm capsule is installed on the calibration gas chamber shell and is communicated with the calibration gas chamber inner chamber.

Described calibration laser emitter comprises collimating apparatus and fiber optic splitter, and described fiber optic splitter one end is connected in the light path of described laser beam emitting device, and the other end of fiber optic splitter is connected in collimating apparatus by optical fiber.

Described calibration laser receiving trap comprises receiver and detector (19), the catoptron (9-6) of described receiver in calibration gas chamber (9), being oppositely arranged with described collimating apparatus (7), and described fiber optic splitter is 2 * 2 fiber optic splitters, an end that connects laser beam emitting device at described fiber optic splitter (3) has second and draws optical fiber, and this optical fiber is connected in described detector (19).

Described laser beam emitting device comprises generating laser, optical fiber collimator and is connected the optical fiber of the two, described laser receiver comprises spatial light---fiber coupler, detector and connection space light---, and the optical fiber of fiber coupler and detector, described detector are connected in described signal Processing display device.

Being provided with the optical beam-expanding device in described optical fiber collimator end, and in described spatial light---the fiber coupler end is provided with the optics bundle device that contracts.

Described generating laser comprises laser diode light source and laser modulation driving circuit.

Described signal Processing display device comprises detector signal pre-process circuit, overhead control and data processing circuit and display module, and described overhead control and data processing circuit are controlled described laser beam emitting device Laser emission, handle the pre-process circuit output signal and shown absorption spectrum at display module.

The core of online self-alignment laser absorption spectrum trace amount gas analysis is to adopt a calibration gas chamber, can contain the gas to be measured of concentration 100% in the self calibration air chamber; In laser diode absorption spectrum gas analysis instrument, increase a self calibration light path, by above-mentioned self calibration air chamber.Its basic light channel structure is as follows: laser diode light source is luminous to be divided into two-way through fiber optic splitter; Lead up to and shine on the detector 17 the output signal entering signal treatment circuit of detector 17 behind the measured gas; Another road then shines on the detector 19 by above-mentioned self calibration air chamber, and the output signal of detector 19 is the entering signal treatment circuit also.Laser diode can be worked on the temperature working point in its allowed band arbitrarily, changes the drive current of laser diode, and the length scanning that makes laser diode is through the above scope of 1nm; Because the absorption line of gas usually than comparatively dense (referring to accompanying drawing 3), no matter from where beginning scanning, can both be swept to the spectral line of one or more in the 1nm scope; Two light paths of synchronous demodulation obtain the absorption spectrum of two light paths.Measure light path because the influence of other gases is arranged, so its absorption spectrum more complicated has many spectrum; 100% the tested gas that the calibration light path is passed through, its absorption spectrum feature is fairly simple; In calibration light path spectrum, look for a spectral line the most significant to do benchmark, record its original light intensity I _{0, ref}With line strength I _RefIn measuring light path spectrum, find the spectral line of relevant position simultaneously, record its original light intensity I _{0, test}With line strength I _TestBecause the gas intensity in the calibration light path is known, utilize above-mentioned formula 1 to list two equations

$\frac{{\mathrm{<figure-callout\; id="0"\; label="I\; ref\; I"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\mathrm{ref}}}{I_{}}=\exp [-S\left(T\right)g(v-{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">v</figure-callout>}}_0^{\&prime;})P_{\mathrm{ref}}{\mathrm{\&rho;}}_{\mathrm{ref}}{L}_{\mathrm{ref}}]---\left(2\right)$

$\frac{I_{\mathrm{test}}}{I_{0,\mathrm{test}}}=\exp [-S\left(T\right)g(v-{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">v</figure-callout>}}_0^{\&prime;})P_{\mathrm{test}}{\mathrm{\&rho;}}_{\mathrm{test}}{L}_{\mathrm{tdst}}]$

Wherein, the parameter of each letter representative is identical with formula (1), subscript ref representative calibration light path, and test represents optical system for testing.Do suitable conversion, elimination line strength and S (T), linear function g (v-v ' ₀) etc. parameter, can get

$\frac{P_{\mathrm{ref}}{\mathrm{\&rho;}}_{\mathrm{ref}}{L}_{\mathrm{ref}}}{P_{\mathrm{test}}{\mathrm{\&rho;}}_{\mathrm{test}}{L}_{\mathrm{test}}}=\frac{{\ln I}_{\mathrm{ref}}-{\ln I}_{0,\mathrm{ref}}}{{\ln I}_{\mathrm{test}}-{\mathrm{<figure-callout\; id="0"\; label="ln\; I"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">ln</figure-callout>}I}_{0,\mathrm{test}}}---\left(3\right)$

If calibration gas chamber need be placed in the tested gas, air pressure inside can change according to ambient pressure, to guarantee that calibration gas chamber has identical temperature and air pressure with tested gas, can eliminate pressure P, parameters such as work temperature are measured (formula 4) thereby the concentration that directly obtains tested gas with the ratio of line strength and work light path realizes self calibration.

${\mathrm{\&rho;}}_{\mathrm{test}}=\frac{\ln I_{\mathrm{test}}-\mathrm{<figure-callout\; id="0"\; label="ln\; I"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">ln</figure-callout>}{I}_{}{}_{0,\mathrm{test}}}{\ln I_{\mathrm{ref}}-\mathrm{<figure-callout\; id="0"\; label="ln\; I"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">ln</figure-callout>}{I}_{}{}_{0,\mathrm{ref}}}\&times;\frac{L_{\mathrm{ref}}}{L_{\mathrm{test}}}\&times;{\mathrm{\&rho;}}_{\mathrm{ref}}---\left(4\right)$

Realize that said method is that the utility model designs a kind of laser absorption spectrum gas trace analysis device, its light path comprises measures light path and calibration light path, two shared laser diodes of light path, by one 2 * 2 fiber optic splitter separately; Measurement light path independent parts comprises Transmission Fibers, optical fiber collimator, optical beam-expanding device, now measurement gas, optics contract and restraints device, spatial light---several sections such as fiber coupler, detector; The calibration light path comprises several sections such as Transmission Fibers, optical fiber collimator, calibration gas chamber, detector.The output of detector directly links to each other in signal processing circuit, the circuit of this device comprises three major parts such as laser diode temperature control, modulation drive circuit, measuring-signal treatment circuit and calibrating signal treatment circuit, and wherein measuring-signal treatment circuit and calibrating signal treatment circuit are identical two cover circuit.

The core of said apparatus " calibration gas chamber " is by being a cylinder type air chamber, two end face is an optical window, can allow the laser of measuring pass through, be connected a pressure diaphragm capsule with cylinder sides, this bellows can variable volume, conditioning chamber internal gas pressure within the specific limits reaches the balance of the outdoor air pressure of box.

Adopt the advantage of above method as follows:

1. the strength ratio of utilizing the calibration light path and measuring the particular spectral lines of light path directly obtains tested gas concentration, has realized real-time measurement and calibration (demarcation), eliminated utilize S (T) and g (v-v ' ₀) error calculated, improved system accuracy.

2. insensitive to the fluctuation of laser diode temperature working point, need not to realize accurate laser diode thermometric, temperature control, greatly reduce the driving circuit complicacy, reduce cost,

3. need not temperature, the pressure and other parameters of extra measurement gas, simplified system has improved reliability.

Therefore, the utility model has comprehensively kept the advantage of tunable laser diodes absorption spectrum gas analysis instrument, compensates its defect, and has simple in structure, REAL-TIME SELF, measuring accuracy advantages of higher.

Description of drawings

Fig. 1 tunable laser diodes absorption spectrum gas analysis instrument course of work synoptic diagram

Near absorption spectra line chart 1580nm of Fig. 2 gas

The P4 of Fig. 3 gas～P7 absorption spectra line chart

Fig. 4 a kind of gas analyzing apparatus embodiment figure of the present utility model

Fig. 5 is a calibration gas chamber structural drawing embodiment illustrated in fig. 4

Fig. 6 is among the signal Processing principle schematic figure embodiment illustrated in fig. 4

1. laser modulation Drive and Control Circuit 2. laser diodes 3. fiber optic splitters

4,5,14. optical fiber 6,7. optical fiber collimator 8. optical beam-expanding devices

9. calibration gas chamber 10. is measured air chamber 11. gas containers to be measured

Bundle device 13. spatial light-fiber coupler 15. display modules 12. optics contracts

16. overhead control and data processing circuit 17,19. detectors

9-1. optical window 9-2. calibrating gas 9-3. pressure diaphragm capsule 9-4. intercommunicating pore

9-5. shell 9-6. catoptron

Embodiment

The utility model is described in further detail below in conjunction with the drawings and specific embodiments.

Referring to accompanying drawing 4, the light path of online self-alignment laser absorption spectrum trace amount gas analytical equipment comprises measures light path and two parts of calibration light path, both shared laser diode light source 2 and fiber optic splitters 3.Wherein, measure the light path independent parts and comprise Transmission Fibers 4, optical fiber collimator 6, optical beam-expanding device 8, gas container to be measured 11, optics contract bundle device 12, spatial light---fiber coupler 13, Transmission Fibers 14, detector 17 several sections such as grade; The calibration light path comprises several sections such as Transmission Fibers 5, optical fiber collimator 7, calibration gas chamber 9, detector 19.In Fig. 4, as gas container 11 to be measured, and the measuring channel that will be communicated with gas pipeline to be measured is measured light path and measurement gas etc. and is all placed in the measuring channel 10 of installing on the on-the-spot pipeline as measuring air chamber 10 with scene gas pipeline to be measured.In addition, this device also comprises laser modulation driving circuit 1, detector signal pre-process circuit 18, overhead control and data processing circuit 16, display module 15 etc.

In the time of work, laser modulation driving circuit 1 driving laser diode 2 is realized length scanning and modulation, and laser instrument output light enters the Transmission Fibers 4 and 5 of measuring light path and calibration light path respectively through beam splitter 3.It is 5 millimeters parallel beam that the light of measuring light path becomes a beam diameter through optical fiber collimator 6, and becoming beam diameter through optical beam-expanding device 8 again is parallel beam about 30mm; The information of carrying absorption line later on by the measurement gas in the gas container 11 to be measured arrives the optics bundle device 12 that contracts and narrows down to 5mm by beam diameter 30mm, passes through spatial light then---and fiber coupler 13 is coupled in the optical fiber 14, and is transferred on the detector 17; After the pretreated circuit 18 of the signal of detector 17 is handled, deliver on overhead control and the data processing circuit 16, through calculating the absorption spectrum of tested gas.

It is that 5 millimeters parallel beam incides in the calibration gas chamber 9 that the light of calibration light path becomes a beam diameter through optical fiber collimator 7, laser is reflected at the end of calibration gas chamber 9, twice through after the calibrating gas, the absorption spectrum information of carrying calibrating gas reflects, in optical fiber collimator 7 coupling transmission back optical fiber 5, pass through fiber optic splitter 3 once more, incide on the detector 19, after the pretreated circuit 18 of the signal of detector 19 is handled, deliver on overhead control and the data processing circuit 16, through calculating the absorption spectrum of calibrating gas.

Referring to accompanying drawing 5, the shell 9-5 of calibration gas chamber 9 is metallic cylinder, and its two ends are installed optical window 9-1 and catoptron 9-6 respectively, and optical fiber collimator 7 is installed on the optical window 9-1; The side of shell 9-5 has individual perforate 9-4, pressure diaphragm capsule 9-3 of welding in the perforate, and shell 9-5 and pressure diaphragm capsule 9-3 form a sealed space together, and the centre is full of 100% the tested gas of normal pressure as calibrating gas 9-2; When ambient pressure changes pressure diaphragm capsule 9-3 can modification with the balance inner and outer air pressure, just the air pressure inside of calibration gas to 9 keeps balances with gas container 11 tested gas atmosphere to be measured all the time; In addition, in the time of measurement, owing to calibration gas chamber 9 is placed in the test environment, so the temperature of inner calibrating gas 9-2 and the temperature of tested gas 11 also are identical.In the time of work, light is behind optical window 9-1 incident process calibrating gas 9-2, and the mirror 9-6 that is reflected reflects, and passes through calibrating gas 9-2 once more, is exported by optical window 9-1 then.

Participate in accompanying drawing 6, obtain after tested gas absorption spectra and the calibrating gas 9-2 absorption spectrum, (Fig. 6 finds a spectral line of intensity maximum in a), measures I at the spectrogram of calibrating gas _{0, ref}And I _Ref, find a spectral line at tested gaseous spectrum figure (6b) correspondence position then, measure I _{0, test}And I _TestBecause the spectrum of tested gas and calibrating gas 9-2 has identical temperature and air pressure, therefore can directly utilize formula

${\mathrm{\&rho;}}_{\mathrm{test}}=\frac{\ln I_{\mathrm{test}}-\mathrm{<figure-callout\; id="0"\; label="ln\; I"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">ln</figure-callout>}{I}_{}{}_{0,\mathrm{test}}}{\ln I_{\mathrm{ref}}-\mathrm{<figure-callout\; id="0"\; label="ln\; I"\; filenames="Y20072018832500161.png,Y20072018832500171.png"\; state="\{\{state\}\}">ln</figure-callout>}{I}_{}{}_{0,\mathrm{ref}}}\&times;\frac{L_{\mathrm{ref}}}{L_{\mathrm{test}}}\&times;{\mathrm{\&rho;}}_{\mathrm{ref}}$

Obtain the concentration of tested gas.

Like this, adopt thinking of the present utility model, need not to know the intensity of concrete spectral line, linear function also need not to know the temperature and the air pressure of tested gas; On the basis that keeps existing tunable laser diodes absorption spectrum trace amount gas analysis advantage, having overcome it demarcates difficulty, needs accurately survey/temperature control, shortcomings such as system complex, can be implemented in trace gas concentration analysis and self calibration under arbitrary temp and the air pressure working environment, improve the precision of system.

Although the utility model be primarily aimed at industry spot laser absorption spectrum trace gas analysis and design, yet application of the present utility model is not limited to industry spot, can be generalized to other laser absorption spectrum gas concentrations that need realize high-acruracy survey and real-time calibration and analyzes occasion.In addition, although the utility model has adopted the calibration gas chamber that has pressure diaphragm capsule to guarantee tested gas and calibrating gas equality of temperature with pressure, and then realize high-precision self calibration; Also can utilize additive method or structure to guarantee that tested gas and calibrating gas equality of temperature are with pressing, even utilize sensor to measure the temperature and pressure of tested gas and calibrating gas respectively, thereby realize self calibration of the present utility model and do not deviate from defined the utility model essence and scope in claims.

Claims (8)

1. laser absorption spectrum trace amount gas analytical equipment, comprise and measure air chamber (10), be respectively equipped with laser beam emitting device and laser receiver at measurement air chamber (10) two ends, described laser receiver is connected with signal Processing display device (15,16,18), it is characterized in that: in described measurement air chamber (10), also be provided with a tubular calibration gas chamber (9), this calibration gas chamber (9) end has calibration laser emitter and calibration laser receiving trap, described calibration laser emitter is connected in the light path of described laser beam emitting device, described calibration laser receiving trap is connected in signal Processing display device (15,16,18), also be provided with the pressure balancing structure of balance air chamber external and internal pressure on the described calibration gas chamber (9).

2. laser absorption spectrum trace amount gas analytical equipment according to claim 1 is characterized in that: described pressure balancing structure is a pressure diaphragm capsule (9-3), and this pressure diaphragm capsule (9-3) is installed on calibration gas chamber shell (9-5) and is communicated with the calibration gas chamber inner chamber.

3. laser absorption spectrum trace amount gas analytical equipment according to claim 1, it is characterized in that: described calibration laser emitter comprises collimating apparatus (7) and fiber optic splitter (3), described fiber optic splitter (3) one ends are connected in the light path of described laser beam emitting device, and the other end of fiber optic splitter (3) is connected in collimating apparatus (7) by optical fiber (5).

4. laser absorption spectrum trace amount gas analytical equipment according to claim 3, it is characterized in that: described calibration laser receiving trap comprises receiver and detector (19), the catoptron (9-6) of described receiver in calibration gas chamber (9), being oppositely arranged with described collimating apparatus (7), and described fiber optic splitter is 2 * 2 fiber optic splitters, an end that connects laser beam emitting device at described fiber optic splitter (3) has second and draws optical fiber, and this optical fiber is connected in described detector (19).

5. laser absorption spectrum trace amount gas analytical equipment according to claim 1, it is characterized in that: described laser beam emitting device comprises generating laser (1,2), optical fiber collimator (6) and the optical fiber that is connected the two (4), the optical fiber (14) of described laser receiver comprises spatial light---fiber coupler (13), detector (17) and connection space light---fiber coupler (13) and detector (17), described detector (17) is connected in described signal Processing display device (15,16,18).

6. laser absorption spectrum trace amount gas analytical equipment according to claim 5, it is characterized in that: be provided with optical beam-expanding device (8) in described optical fiber collimator (6) end, and in described spatial light---fiber coupler (13) end is provided with the optics bundle device (12) that contracts.

7. laser absorption spectrum trace amount gas analytical equipment according to claim 5 is characterized in that: described generating laser (1,2) comprises laser diode light source (2) and laser modulation driving circuit (1).

8. laser absorption spectrum trace amount gas analytical equipment according to claim 1, it is characterized in that: described signal Processing display device comprises detector signal pre-process circuit (18), overhead control and data processing circuit (16) and display module (15), and described overhead control and data processing circuit (16) are controlled described laser beam emitting device Laser emission, handle pre-process circuit (18) output signal and shown absorption spectrum at display module (15).

Images