CN110632013A - Gas spectrum analyzer - Google Patents
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- CN110632013A CN110632013A CN201910941394.3A CN201910941394A CN110632013A CN 110632013 A CN110632013 A CN 110632013A CN 201910941394 A CN201910941394 A CN 201910941394A CN 110632013 A CN110632013 A CN 110632013A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
Abstract
The invention discloses a gas spectrum analyzer, which comprises an ultraviolet light source, a lens group, an ultraviolet multiple reflection pool, an automatic calibration pool, an ultraviolet optical fiber, an optical fiber spectrum analyzer and a transmission control unit, wherein the ultraviolet light source is arranged on the ultraviolet multiple reflection pool; the ultraviolet light source, the lens group, the ultraviolet reflecting pool and the automatic calibration pool form a unique ultraviolet spectrum detection structure; the ultraviolet light source sequentially passes through the lens group, the ultraviolet multi-reflection pool, the automatic calibration pool, the ultraviolet optical fiber and the beam expansion, the multi-reflection, the calibration, the transmission and the optical fiber spectrum analysis of the optical fiber spectrometer to obtain a gas spectrum analysis result; the transmission control unit is communicated with the optical fiber spectrometer to realize gas data acquisition, analysis, processing and uploading. The invention uses the small ultraviolet multiple reflection pool to greatly expand the measuring optical path, realizes the miniaturization of equipment under the condition of ensuring the high precision of the measuring result, and simultaneously realizes the linear measurement within the range of the optical path, so that the measuring result is more representative and more reliable; and a multi-component DOAS filtering algorithm is adopted, so that the problems of ultraviolet band environment and multi-component cross interference are solved, and the monitoring precision and accuracy are improved.
Description
Technical Field
The invention belongs to the technical field of spectral analysis and gas monitoring, and particularly relates to a gas spectrum analyzer.
Background
With the rapid development of industries, transportation and other industries, particularly the heavy use of coal and petroleum, a great amount of harmful substances such as smoke dust, sulfur dioxide, nitrogen oxides, carbon monoxide, hydrocarbons and the like are generated. These harmful substances are continuously discharged into the atmosphere, and when the content exceeds the limit allowed by the environment and lasts for a certain time, the normal composition of the atmosphere, especially the air, is changed, the natural physical, chemical and ecological balance system is destroyed, the life, work and health of people are harmed, and the natural resources, property, utensils and the like are damaged, and the condition is called as atmospheric pollution or air pollution. The atmospheric environment is a necessary condition for human survival and development, the protection and improvement of the quality of the atmospheric environment have very important significance for promoting the development of human society and economy and guaranteeing human health, and the protection and supervision of the atmospheric environment depend on atmospheric environment monitoring.
Common on-site monitoring methods for pollution sources can be divided into optical methods and non-optical methods. The optical methods comprise ultraviolet and infrared photometry and spectral analysis, and the non-optical methods mainly comprise electrochemical methods, chromatography, mass spectrometry and the like. For an on-site chemical industry park instrument, an electrochemical gas sensor is small in size and can be applied to portable on-site measurement, but the electrochemical gas sensor has the defects that a corresponding gas sensor needs to be configured for each gas, only the point-type measurement of the current position can be carried out, the service life is short, and the measurement failure is easily caused by poisoning; the chromatography has high-efficiency separation performance on multi-component compounds, and the mass spectrometry has excellent structure identification and sensitive and accurate quantification capability, but has lower time resolution, high cost and complex operation, and is not suitable for portable field real-time measurement. The electrochemical method is mostly adopted for on-site monitoring of chemical industrial parks developed in China, compared with the traditional electrochemical and gas chromatographic methods, the optical method has the advantages of rapidness, simplicity and accuracy, wherein the ultraviolet spectroscopy also has the advantages of capability of simultaneously measuring various gas components, small size of a detection device and the like, and is the current development trend. The existing optical monitoring instrument has larger volume or lower precision, is not suitable for the requirements of a chemical industrial park required by supervised monitoring, and does not have a miniaturized high-precision online gas monitoring product based on an ultraviolet absorption spectrum technology.
Differential absorption spectroscopy (DOAS) is mainly used to study the trace gas components of the atmosphere by using the characteristic absorption of absorbing molecules in the ultraviolet to visible light range. The differential absorption spectroscopy technology is to identify gas components by utilizing the narrow-band absorption characteristics of gas molecules in air and deduce the concentration of the gas according to the narrow-band absorption intensity, so that the differential absorption spectroscopy method has the advantages which cannot be compared with the traditional detection method.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a gas spectrum analyzer aiming at the defects of the prior art, solve the problem that the volume and the precision of the existing optical detector are incompatible, and realize the field real-time measurement with small volume, high precision, convenient installation and simple operation.
In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:
a gas spectrum analyzer comprises an ultraviolet light source, a lens group, a small ultraviolet multiple reflection cell, an automatic calibration cell, an ultraviolet optical fiber, a fiber spectrum analyzer and a transmission control unit;
the ultraviolet light source, the lens group, the small ultraviolet reflecting pool and the automatic calibration pool form a unique ultraviolet spectrum detection structure;
the ultraviolet light source sequentially passes through the lens group, the small ultraviolet multiple reflection pool, the automatic calibration pool, the ultraviolet optical fiber and the optical fiber spectrometer;
the ultraviolet light source sequentially passes through the lens group, the small ultraviolet multiple reflection pool, the automatic calibration pool, the ultraviolet optical fiber and the beam expansion, multiple reflection, calibration, transmission and optical fiber spectrum analysis of the optical fiber spectrometer to obtain a gas spectrum analysis result;
the transmission control unit is communicated with the optical fiber spectrometer to realize gas data acquisition, analysis, processing and uploading.
In order to optimize the technical scheme, the specific measures adopted further comprise:
the ultraviolet light source is a deuterium lamp, the spectrum range covers the ultraviolet spectrum of 180-400 nm, the diameter of the light emitting surface is phi 1mm, and the deuterium lamp is provided with a multi-fin aluminum alloy shell.
The lens group is a collimating lens group and adopts an inverted structure of a Galileo telescope, the front lens group is a short-focus positive lens, the rear lens group is a positive lens group formed by combining a positive lens and a negative lens, the lenses are all made of quartz (JGS1) glass, and ultraviolet antireflection films with the thickness of 180-400 nm are plated on the lenses.
The ultraviolet multi-reflection pool is formed by the conjugated arrangement of concave spherical reflectors A, B and C with the same curvature radius, wherein the reflector A is a main reflector, the reflectors B and C are auxiliary reflectors, and the reflectors B and C are arranged side by side;
substrates of the reflectors A, B and C are made of K9 glass and plated with reinforced aluminum films, and the reflectivity of the substrates to ultraviolet 190-310 nm wave bands is larger than 90%;
the ultraviolet multiple reflection tank is of a Whtie type, and the gas absorption optical distance in the white tank is calculated by a formula:
La＝n×L＝2(N+1)×L
wherein N is the number of light spots on the primary mirror, and L is the cavity length of the white cell;
the cavity length of the white cell is 600mm, the white cell is reflected back and forth for 20 times, and the whole gas absorption optical path is 12 m.
The automatic calibration pool adopts an aspheric single lens as an objective lens, and the aspheric single lens has the following specific parameters: clear aperture phi of 24mm, center thickness of 5.75mm, focal length of 50mm, eccentricity e2The coating is-0.59, made of JGS1 and plated with an ultraviolet antireflection film of 180-400 nm.
The ultraviolet absorptivity of the ultraviolet optical fiber is lower than 10%.
The optical fiber spectrometer adopts a symmetrical Czerny-Turner optical structure, and two concave reflectors are used for replacing a single reflector used in a Fasati-Ebert device;
the wavelength range of the fiber spectrometer is 185-340nm, a 2048 unit linear array ultraviolet sensitive silicon CCD and an 1800 line blazed grating are used, the slit width is 50 microns, and the wavelength resolution is superior to 0.5 nm.
The transmission control unit adopts a DSP series single chip microcomputer as a control core, adopts an RS232/RS485 standard communication interface and is provided with a wireless communication module.
The gas spectrum analyzer adopts a multi-component DOAS filtering algorithm, and the multi-component DOAS filtering algorithm is a combination of binomial coefficient filtering, polynomial fitting filtering and Savitzky-Golay filtering.
The invention has the following beneficial effects:
1. the invention adopts ultraviolet light as a light source, the ultraviolet light is not easily absorbed by water molecules, and the wet gas can be directly analyzed;
2. compared with the traditional DOAS system, the invention is characterized in that the open light path is replaced by the multi-reflection cell technology, the detection sensitivity can be improved by increasing the detection light path according to the principle of measuring the gas concentration by the Lambert-Beer law, and the absorption light path of the gas is obviously increased by completing the multi-reflection of the light beam in a small volume by using the multi-reflection cell, thereby realizing the following advantages:
small volume: the volume of the equipment is less than 0.2 cubic meter;
high precision: the detection limit reaches below 100ppb, and the detection limit of partial gases such as SO2, NH3 and the like can reach below 5 ppb;
quick response: response time is below 45 s;
monitoring multiple gases simultaneously: can simultaneously monitor NH3、NO2、SO2、CS2Benzene, toluene, formaldehyde, butadiene, etc.
3. The invention is different from the point measurement of the traditional electrochemical sensor, and realizes the line measurement in the optical path range by using the small ultraviolet multiple reflection pool, so that the measurement result is more representative and more reliable.
4. The invention adopts a multi-component DOAS filtering algorithm, solves the problems of ultraviolet band environment and multi-component cross interference, and improves the monitoring precision and accuracy.
Drawings
FIG. 1 is a schematic view of a modular link for a gas spectrum analyzer according to the present invention;
FIG. 2 is a graph of a deuterium lamp spectrum;
FIG. 3 is a diagram of a lens assembly optical path system;
FIG. 4 is a diagram of a multiple reflection cell optical path system;
FIG. 5 is a graph of spectral reflectance of a reflectance cell;
FIG. 6 is a schematic diagram of an optical path of an aspheric focusing lens;
FIG. 7 is a diagram of spot arrays of aspheric focusing lenses;
FIG. 8 is a graph of the broad and narrow bands in the absorption spectrum;
wherein the reference numerals are: the device comprises an ultraviolet light source 1, a lens group 2, an ultraviolet multi-reflection pool 3, an automatic calibration pool 4, an ultraviolet optical fiber 5, an optical fiber spectrometer 6 and a transmission control unit 7.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
The gas spectrum analyzer is based on the beer-Lambert law, adopts a unique ultraviolet spectrum detection structure, utilizes a differential absorption spectrum technology, combines a small ultraviolet multiple reflection cell and a fiber optic spectrometer, and realizes real-time online monitoring on various polluted gases. By the small ultraviolet multiple reflection pool technology, the optical path is larger than 10 meters, the reflectivity is improved, the stray light is reduced, the monitoring precision is improved, the size is reduced, and the sensitivity and the portability requirements of the unstructured emission field detection are met.
By combining a Multi-Filter technology of a plurality of digital filtering methods such as binomial coefficient filtering, polynomial fitting filtering, Savitzky-Golay filtering and the like, and adopting a Multi-component DOAS filtering algorithm according to gas absorption characteristics, the problems of ultraviolet band environment and Multi-component cross interference are solved, and the monitoring precision and accuracy are improved.
As shown in fig. 1, the gas spectrum analyzer of the present invention includes an ultraviolet light source 1, a lens group 2, an ultraviolet multiple reflection cell 3, an automatic calibration cell 4, an ultraviolet optical fiber 5, a fiber spectrometer 6, and a transmission control unit 7;
the ultraviolet light source 1, the lens group 2, the ultraviolet reflecting pool 3 and the automatic calibration pool 4 form a unique ultraviolet spectrum detection structure;
the ultraviolet light source 1 sequentially passes through a lens group 2, an ultraviolet multi-reflection pool 3, an automatic calibration pool 4, an ultraviolet optical fiber 5 and an optical fiber spectrometer 6;
the ultraviolet light source 1 sequentially passes through the lens group 2, the ultraviolet multi-reflection pool 3, the automatic calibration pool 4, the ultraviolet optical fiber 5 and the optical fiber spectrometer 6 for beam expansion, multi-reflection, calibration, transmission and optical fiber spectrum analysis to obtain a gas spectrum analysis result;
the transmission control unit 7 is communicated with the optical fiber spectrometer 6 to realize gas data acquisition, analysis, processing and uploading.
In the embodiment, as shown in fig. 2, the ultraviolet light source 1 is a deuterium lamp, the spectrum range covers the ultraviolet spectrum of 180-400 nm, the diameter of the light emitting surface is about Φ 1mm, and the deuterium lamp has a multi-fin aluminum alloy shell.
The surface temperature of the deuterium lamp is very high when the system works, in order to ensure the reliability and stability of the deuterium lamp during working and prolong the service life of the deuterium lamp, a multi-fin aluminum alloy shell is designed, the deuterium lamp is arranged in the multi-fin aluminum alloy shell, a heat transfer mode of diffusion fit conduction is adopted, and then forced air cooling is utilized to meet the temperature requirement.
The designed device can adjust the position of the light emitting surface of the deuterium lamp and can fix the deuterium lamp. On one hand, the heat dissipation efficiency of the deuterium lamp is improved, and on the other hand, the heat dissipation device also has the functions of reducing stray light and protecting a light source system.
In the embodiment, the lens group 2 is a collimating lens group, which may also be called a beam expander. In order to avoid the light spot divergence caused by the overlarge divergence angle of the deuterium lamp light beam, the transmission distance of the light beam is increased, namely the divergence angle of the light beam is reduced, the collimation is improved, and the light beam expander is designed to improve the divergence angle.
The inverted structure of Galileo telescope is adopted, the front group of lenses is composed of a short-focus positive lens, the divergent light beam of the deuterium lamp is firstly preliminarily collimated, a certain object space aperture angle is ensured, light energy is received as much as possible, and the rear group of lenses adopts a positive lens group formed by combining the positive lens and the negative lens to correct spherical aberration. By controlling the distance between the three lenses and the thickness of each lens, the deuterium lamp beam can be well collimated, and the divergence angle of the deuterium lamp beam is controlled to be about 1 degree, as shown in fig. 3.
The lenses are made of quartz (JGS1) glass and are plated with ultraviolet antireflection films of 180-400 nm, so that the transmittance of ultraviolet light beams is improved better.
As shown in fig. 4, in the embodiment, the ultraviolet multiple reflection cell 3 is configured by conjugating concave spherical mirrors A, B and C with the same curvature radius, the mirror a is a primary mirror, the mirrors B and C are secondary mirrors, and the mirrors B and C are arranged side by side;
the loss of light intensity in the white cell is mainly caused by gas absorption and low reflectivity of the lens, and high requirements are put forward on the ultraviolet coating technology. The substrate of the concave reflector is made of K9 glass, and the polishing is as high as possible, so that the coating efficiency is improved. Because the coating wave band is too wide, the reflectivity is improved by plating an enhanced aluminum film, and the reflectivity of the coating on the wave band of 190-310 nm ultraviolet is about 90 percent, as shown in figure 5.
The ultraviolet multiple reflection tank is of a Whtie type, and the gas absorption optical distance in the white tank is calculated by a formula:
La＝n×L＝2(N+1)×L
wherein N is the number of light spots on the primary mirror, and L is the cavity length of the white cell;
because the content of toxic gas in the atmospheric environment is in ppb-ppm magnitude, in order to reduce the detection lower limit of the instrument and enable the instrument to meet the requirement of detecting trace gas, the detection sensitivity can be improved by increasing the detection optical path according to the principle of measuring the gas concentration by the Lambert-Beer law, and the absorption optical path of the gas can be obviously increased by utilizing the multiple reflection cell to enable the light beam to complete multiple reflections in a small volume. Considering the system portability and the measured gas requirement, the cavity length of the white cell is 600mm, the back and forth reflection is 20 times, the whole gas absorption optical path is 12m, and the formula can obtain that N is 9. .
In the embodiment, the automatic calibration tank 4 adopts an aspheric single lens as an objective lens, and forms a focusing system of the coupling optical fiber as a simple objective lens, so that the problem of energy loss caused by difficulty in forming small light spots due to a large divergence angle of an emergent light beam and a large off-axis aberration is solved.
The specific parameters of the aspheric lens are as follows: clear aperture of phi 24mm, center thickness of 5.75mm, focal length50mm, eccentricity e2The material is JGS1, and the ultraviolet antireflection film with the thickness of 180-400 nm is plated, as shown in figure 6. The spot alignment before and after the correction of the aspheric surface in the receiving field is shown in fig. 7.
In the embodiment, the ultraviolet optical fiber 6 is a customized high-performance ultraviolet optical fiber, and has a small dispersion coefficient, an ultraviolet absorption rate lower than 10% and high mechanical strength.
In the embodiment, the fiber spectrometer 6 can improve the optical resolution by increasing the groove density of the diffraction grating, but at the expense of the spectrum range and the signal intensity; reducing the slit width or fiber diameter increases optical resolution, which results in reduced signal strength. By researching the absorption characteristics of the polluted gas in an ultraviolet band and adopting a symmetrical Czerny-Turner optical structure design, the stray light generated by extra absorption and scattering can be avoided, and the volume of the spectrometer is reduced. The wavelength range of the fiber spectrometer 6 is 185-340nm, a 2048 unit linear array ultraviolet sensitive silicon CCD is used, the slit width is 50 microns, and the wavelength resolution is superior to 0.5 nm.
In the embodiment, the transmission control unit 7 adopts a DSP series single chip microcomputer as a control core, adopts an RS232/RS485 standard communication interface, is provided with a wireless communication module, and can directly upload acquired data to a server platform.
The shell of the invention is made of aluminum alloy material, and the whole volume is less than 0.2 cubic meter.
In an embodiment, the gas spectrum analyzer employs a multi-component DOAS filtering algorithm that is a combination of binomial coefficient filtering, polynomial fitting filtering, and Savitzky-Golay filtering.
The DOAS technology used by the gas spectrum analyzer eliminates molecular absorption and scattering phenomena in actual gas measurement, and when a light beam passes through a gas mass to be measured, the light beam is influenced by Rayleigh scattering, meter scattering and Raman scattering, wherein the Rayleigh scattering and the Raman scattering are caused by gas molecules, and the meter scattering is caused by aerosol particles or smoke dust. Lambert-beer's law cannot be directly applied to actual atmospheric measurements.
In the example DOAS technology is a qualitative and quantitative measure by analyzing the "fingerprint" absorption of light radiation by different molecules, so that other processes of action are considered perturbations and need to be removed. Both the meter scattering and the Rayleigh scattering are slowly changed along with the wavelength, and have larger weakening influence on the light intensity; fluorescence (secondary luminescence λ '> λ) and raman scattering (anti-stokes lines and stokes lines generated are λ' ═ λ ± λ v, respectively) depend on the internal structure of the molecular energy level, with little effect on the attenuation of light intensity. Thus, it can be described as:
in the formula I0(λ) is the emitted light intensity; i (lambda) is the received light intensity after atmospheric absorption; sigmai(λ) is the absorption cross section of the ith gas molecule; l is the optical path length; c. CiIs the average concentration of the ith gas molecule in the optical path. EpsilonR(lambda) and epsilonMRespectively representing the attenuation of light intensity caused by Rayleigh scattering and meter scattering.
The basic principle of DOAS technology is to solve this problem by dividing the absorption cross section into two parts.
σi(λ)＝σi,b(λ)+σ′i(λ)
In the formula sigmai,b(λ) varies slowly with wavelength λ, σ'i(λ) is a portion that varies rapidly with wavelength λ. The broadband and narrowband portions of the absorption spectrum are shown in fig. 8.
After the section is divided into two parts, it can be expressed as:
I(λ)＝I0(λ)·exp[-L∑(σ′i(λ)ci)]·exp[-L(∑(σi,b(λ)ci)+εR(λ)+εM(λ))]·A(λ)
wherein the first exponential function describes the differential absorption of the trace gas; the second term is the effect of slowly varying absorption of trace gases in the atmosphere and rayleigh and mie scattering, and the attenuation factor a (λ) describes the slow variation of optical transmission with wavelength. We define the variable I'0(lambda) denotes the light intensity without differential absorption,i.e. the slow-varying part:
I′0(λ)＝I0(λ)·exp[-L(∑(σi,b(λ)ci)+εR(λ)+εM(λ))]·A(λ)
the equation becomes:
I(λ)＝I′0(λ)×exp[-L∑(σ′i(λ)ci)]
i (λ) contains only narrow-band absorbing structures; i'0Is interpolated into a sufficiently narrow absorption line of some kind. σ (λ) is typically measured in the laboratory (or obtained from the literature) and then numerically filtered to yield a differential absorption cross-section σ' (λ). Obtaining a differential optical density:
D′＝log(I′0(λ)/I(λ))＝L∑(σ′i(λ)ci)
knowing L, deriving D 'and σ' (λ) from D and σ (λ), the concentration of a molecule can be calculated.
Since the gas molecules have respective characteristic absorption cross-sections, their concentration can be determined by studying the characteristic absorption of the gas to the light radiation.
In the embodiment, the gas spectrum analyzer supports simultaneous monitoring of the contents of various gases in the near ultraviolet spectral region covering the wavelength of 185-340 nm.
The gas spectrum analyzer adopts the small ultraviolet multiple reflection pool 4, thereby increasing the optical distance and reducing the volume, leading the device structure to be compact, leading the shell volume to be small and being convenient for installation and transportation.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.
Claims (9)
1. A kind of gas spectrum analyzer, characterized by: the system comprises an ultraviolet light source (1), a lens group (2), a small ultraviolet multi-reflection pool (3), an automatic calibration pool (4), an ultraviolet optical fiber (5), an optical fiber spectrometer (6) and a transmission control unit (7);
the ultraviolet light source (1), the lens group (2), the small ultraviolet multi-reflection pool (3) and the automatic calibration pool (4) form an ultraviolet spectrum detection structure;
the ultraviolet light source (1) sequentially passes through the lens group (2), the small ultraviolet multi-reflection pool (3), the automatic calibration pool (4), the ultraviolet optical fiber (5) and the optical fiber spectrometer (6);
the ultraviolet light source (1) sequentially passes through a lens group (2), a small ultraviolet multiple reflection pool (3), an automatic calibration pool (4), an ultraviolet optical fiber (5) and an optical fiber spectrometer (6) for beam expansion, multiple reflection, calibration, transmission and optical fiber spectrum analysis to obtain a gas spectrum analysis result;
the transmission control unit (7) is communicated with the optical fiber spectrometer (6) to realize gas data acquisition, analysis, processing and uploading.
2. A gas spectrum analyzer as defined in claim 1 wherein:
the ultraviolet light source (1) is a deuterium lamp, the spectrum range covers the ultraviolet spectrum of 180-400 nm, the diameter of the light emitting surface is phi 1mm, and the deuterium lamp is provided with a multi-fin aluminum alloy shell.
3. A gas spectrum analyzer as defined in claim 1 wherein:
the lens group (2) is a collimation lens group and is provided with a beam expander to improve the divergence angle of the collimation lens group;
the lens group (2) adopts an inverted structure of a Galileo telescope, the front lens group is composed of a short-focus positive lens, the divergent light beam of the deuterium lamp is preliminarily collimated, a certain object space aperture angle is ensured, light energy is received as much as possible, and the rear lens group is a positive lens group formed by combining a positive lens and a negative lens and used for correcting spherical aberration; by controlling the distance between the three lenses and the thickness of each lens, the deuterium lamp beam is well collimated, and the divergence angle of the deuterium lamp beam is controlled to be about 1 degree.
The lenses are made of quartz glass and are plated with ultraviolet antireflection films of 180-400 nm.
4. A gas spectrum analyzer as defined in claim 1 wherein:
the ultraviolet multi-reflection pool (3) is formed by conjugatively arranging concave spherical reflectors A, B and C with the same curvature radius, wherein the reflector A is a main reflector, the reflectors B and C are auxiliary reflectors, and the reflectors B and C are arranged side by side;
substrates of the reflectors A, B and C are made of K9 glass and plated with reinforced aluminum films, and the reflectivity of the substrates to ultraviolet 190-310 nm wave bands is larger than 90%;
the ultraviolet multiple reflection tank is of a Whtie type, and the gas absorption optical distance in the white tank is calculated by a formula:
La＝n×L＝2(N+1)×L
wherein N is the number of light spots on the primary mirror, and L is the cavity length of the white cell;
the cavity length of the white cell is 600mm, the white cell is reflected back and forth for 20 times, and the whole gas absorption optical path is 12 m.
5. A gas spectrum analyzer as defined in claim 1 wherein:
the automatic calibration pool (4) adopts an aspheric single lens as an objective lens, and the aspheric single lens has the following specific parameters: clear aperture phi of 24mm, center thickness of 5.75mm, focal length of 50mm, eccentricity e2The coating is-0.59, made of JGS1 and plated with an ultraviolet antireflection film of 180-400 nm.
6. A gas spectrum analyzer as defined in claim 1 wherein:
the ultraviolet absorption rate of the ultraviolet optical fiber (6) is lower than 10%.
7. A gas spectrum analyzer as defined in claim 1 wherein:
the optical fiber spectrometer (6) adopts a symmetrical Czerny-Turner optical structure, and two concave mirrors are used for replacing a single mirror used in a Fasati-Ebert device;
the wavelength range of the fiber spectrometer (6) is 185-340nm, a 2048 unit linear array ultraviolet sensitive silicon CCD and an 1800 line blazed grating are used, the slit width is 50 microns, and the wavelength resolution is superior to 0.5 nm.
8. A gas spectrum analyzer as defined in claim 1 wherein:
the transmission control unit (7) adopts a DSP series single chip microcomputer as a control core, adopts an RS232/RS485 standard communication interface and is provided with a wireless communication module.
9. A gas spectrum analyzer as defined in claim 1 wherein:
the gas spectrum analyzer adopts a multi-component DOAS filtering algorithm, and the multi-component DOAS filtering algorithm is a combination of binomial coefficient filtering, polynomial fitting filtering and Savitzky-Golay filtering.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910941394.3A CN110632013A (en) | 2019-09-30 | 2019-09-30 | Gas spectrum analyzer |
| PCT/CN2020/091143 WO2021063003A1 (en) | 2019-09-30 | 2020-05-20 | Gas spectrum analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910941394.3A CN110632013A (en) | 2019-09-30 | 2019-09-30 | Gas spectrum analyzer |
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| CN110632013A true CN110632013A (en) | 2019-12-31 |
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| CN201910941394.3A Pending CN110632013A (en) | 2019-09-30 | 2019-09-30 | Gas spectrum analyzer |
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| WO (1) | WO2021063003A1 (en) |
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| JP4775798B2 (en) * | 2006-05-18 | 2011-09-21 | 独立行政法人科学技術振興機構 | Multiple gas concentration simultaneous measurement device |
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| CN106018310A (en) * | 2016-05-17 | 2016-10-12 | 广东电网有限责任公司电力科学研究院 | Gas component detection method and device based on ultraviolet spectroscopy |
| CN108051388A (en) * | 2018-01-16 | 2018-05-18 | 武汉敢为科技有限公司 | A kind of H2S gas ultraviolet spectra detection devices and its method |
| CN110632013A (en) * | 2019-09-30 | 2019-12-31 | 南京云创大数据科技股份有限公司 | Gas spectrum analyzer |
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2019
- 2019-09-30 CN CN201910941394.3A patent/CN110632013A/en active Pending
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- 2020-05-20 WO PCT/CN2020/091143 patent/WO2021063003A1/en active Application Filing
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