Method for synchronously detecting concentration of mixed gas based on continuous wide-spectrum laser light source
Through the continuous wide spectrum laser light source beam splitting and adjustable grating control method, the problem of low detection efficiency of mixed gas is solved, and the effect of efficient detection of multiple gas types and concentrations is achieved.
Patent Information
- Application Number
- CN202510853957.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-24
- Publication Date
- 2025-08-12
AI Technical Summary
In the prior art, the mixed gas detection method is low in efficiency and low in accuracy, making it difficult to detect the types and concentrations of multiple gases simultaneously.
After the beam splitting is performed by a continuous wide spectrum laser light source, the gas type is determined by the first beam of laser, and the second beam of laser selects a preset wavelength transmission under the control of an adjustable grating, and combines the detector to measure the intensity of the transmitted laser and calculate the gas concentration.
It realizes the detection of multiple gas types and concentrations in the mixed gas simultaneously, and improves the detection efficiency.
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Figure CN120468087A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of laser detection technology, and in particular to a method for synchronously detecting the concentration of mixed gases based on a continuous wide-spectrum laser light source. Background Art
[0002] In industrial production and scientific research, the composition of mixed gases often needs to be measured in advance so that further research can be carried out based on the concentration of each gas in the mixed gas.
[0003] In the existing technology, mixed gas detection often adopts a relatively single detection method, which can only detect one or a few gases, or can only detect specific gases of known gas types. The detection efficiency is low and the detection accuracy is not high, which brings inconvenience to scientific research or industrial production. Summary of the Invention
[0004] Some embodiments of the present invention provide a method for synchronously detecting the concentration of a mixed gas based on a continuous broadband laser light source, which can solve at least one of the above technical problems, as follows:
[0005] Some embodiments of the present invention provide a method for synchronously detecting the concentration of a mixed gas based on a continuous broadband laser light source, comprising the following steps:
[0006] A continuous broadband laser light source is split into two continuous broadband laser beams after passing through a beam splitter. The first continuous broadband laser beam is transmitted along the original optical path, and the second continuous broadband laser beam is transmitted perpendicular to the original optical path. The continuous broadband laser light source is a supercontinuum laser light source with an output wavelength of 700-2400nm. The beam splitter is a 45-degree flat mirror coated with a 50% transmission film system and a 50% reflection film system with a wavelength of 700-2400nm, which is used to equally split the laser input to the beam splitter.
[0007] The first continuous wide-spectrum laser beam is focused into a first gas sample pool to be measured via a first focusing lens. The laser beam focused into the first gas sample pool is absorbed by the gas to be measured and then input into a precision spectrometer via a second focusing lens. The precision spectrometer is used to detect the absorption spectrum after passing through the first gas sample pool to be measured. The precision spectrometer is connected to a computer, and the type of the gas to be measured in the first gas sample pool to be measured can be determined by the computer.
[0008] The second continuous wide-spectrum laser beam is input into an adjustable grating through a 45-degree reflector. The adjustable grating selects at least one laser beam of a preset wavelength for transmission under the control of the computer. The preset wavelength corresponds to the type of the gas to be measured. The transmitted laser beam is focused into a second gas sample cell to be measured through a third focusing mirror. The transmitted laser beam focused into the second gas sample cell to be measured is absorbed by the gas to be measured and then input into a laser absorption device through a fourth focusing mirror. A first detector and a second detector are provided to respectively measure the intensity of the transmitted laser beam before and after input into the second gas sample cell to be measured, and the measurement results are input into the computer.
[0009] The computer calculates the concentration of the corresponding absorption gas according to the measurement results of the first detector and the second detector.
[0010] In some embodiments, the gas species is oxygen, hydrogen fluoride, acetylene, ammonia, methane, hydrogen sulfide, ethylene, hydrogen chloride, and hydrogen.
[0011] In some embodiments, the preset wavelengths are 761 nm, 1278 nm, 1520.1 nm, 1530 nm, 1653.7 nm, 1578 nm, 1620 nm, 1742 nm, and 2122.0 nm.
[0012] In some embodiments, the first focusing mirror and the third focusing mirror are plano-convex lenses with a focal length of 200 mm, and are used to focus the detection laser onto the center position of the first gas sample cell to be measured and the second gas sample cell to be measured, respectively.
[0013] In some embodiments, the first gas sample cell to be measured and the second gas sample cell to be measured are exactly the same.
[0014] In some embodiments, the first detector and the second detector are power meters and / or spectrometers.
[0015] In some embodiments, the second beam of continuous wide-spectrum laser light passes through multiple beam splitters and is simultaneously input into multiple adjustable gratings. The multiple adjustable gratings select a laser beam of a preset wavelength for transmission under the control of the computer. The multiple adjustable gratings output multiple transmitted laser beams of corresponding wavelengths. The multiple transmitted laser beams of corresponding wavelengths are respectively focused into multiple second gas sample pools to be tested. Multiple first detectors and multiple second detectors are provided to respectively measure the intensity of the transmitted laser beam before and after input into the second gas sample pool to be tested, and the measurement results are input into the computer.
[0016] In some embodiments, the concentration of the absorption gas satisfies the following relationship:
[0017] P=(2πSλ) / (LhB)
[0018]
[0019] P is the concentration of the gas to be measured, λ is the absorption peak wavelength of the gas to be measured, S is the area enclosed by the gas absorption peak, B is the gas absorption transition constant, L is the length of the gas sample cell to be measured, h is Planck's constant, I(ω) is the outgoing laser intensity, and I0(ω) is the incident laser intensity.
[0020] In some embodiments, the continuous broadband laser light source includes: a 1310 nm femtosecond laser, a coupling system, and a photonic crystal fiber. The 1310 nm femtosecond laser excites the photonic crystal fiber to produce multi-order nonlinear effects, thereby generating a 700-2400 nm continuous broadband laser output.
[0021] In some embodiments, the transmitted laser is a narrow linewidth laser.
[0022] Compared with the related art, the present invention has at least the following technical effects:
[0023] The present invention provides a method for synchronously detecting the concentration of mixed gases based on a continuous wide-spectrum laser light source. The method adopts a continuous wide-spectrum laser light source for detection, and can simultaneously detect the types and concentrations of multiple gases in the mixed gas, thereby improving the detection efficiency of the mixed gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0025] Figure 1 A schematic diagram of an optical path structure for synchronously detecting the concentration of a mixed gas based on a continuous broadband laser light source provided in some embodiments of the present invention;
[0026] Figure 2 A schematic diagram of a spectrum simulation state provided by some embodiments of the present invention;
[0027] Figure 3 Schematic diagram of an optical path structure for synchronously detecting the concentration of a mixed gas based on a continuous wide-spectrum laser light source provided in other embodiments of the present invention;
[0028] Figure 4 A schematic diagram of the structure of a continuous broadband laser light source provided by some embodiments of the present invention;
[0029] Explanation of the accompanying symbols: continuous broadband laser light source 1, femtosecond laser 1-1, coupling system 1-2, photonic crystal fiber 1-3, beam splitter 2, first focusing mirror 3, first gas sample pool to be measured 4, second focusing mirror 5, precision spectrometer 6, computer 7, reflector 8, adjustable grating 9, third focusing mirror 10, first detector 11, second gas sample pool to be measured 12, fourth focusing mirror 13, second detector 14, laser absorption device 15. DETAILED DESCRIPTION
[0030] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings. It is apparent that the embodiments described are only some, not all, of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.
[0031] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a," "an," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.
[0032] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.
[0033] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprising a" does not exclude the presence of other identical elements in the product or device comprising the element.
[0034] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0035] Please refer to Figure 1 Some embodiments of the present invention provide a method for synchronously detecting the concentration of a mixed gas based on a continuous broadband laser light source, comprising the following steps:
[0036] Step S102: The continuous broadband laser light source 1 is divided into two continuous broadband laser beams after passing through the beam splitter 2, the first continuous broadband laser beam is transmitted along the original optical path, and the second continuous broadband laser beam is transmitted perpendicular to the original optical path; wherein the continuous broadband laser light source 1 is a supercontinuum laser light source with an output wavelength of 700-2400nm; the beam splitter 2 is a 45-degree flat mirror coated with a 50% transmission film system and a 50% reflection film system of 700-2400nm, and is used to equally divide the laser input into the beam splitter; optionally, the first continuous broadband laser beam and the second continuous broadband laser beam do not need to be equally divided, and the beam splitter 2 uses a 45-degree flat mirror coated with a 30%-70% transmission film system and a 70%-30% reflection film system of 700-2400nm to split the first continuous broadband laser beam and the second continuous broadband laser beam in a ratio of 3:7-7:3.
[0037] Step S104: The first continuous wide-spectrum laser beam is focused by the first focusing lens 3 into the first gas sample pool 4 to be tested. The laser beam focused into the first gas sample pool 4 is absorbed by the gas to be tested and then input into the precision spectrometer 6 through the second focusing lens 5. The precision spectrometer 6 is used to detect the absorption spectrum after passing through the first gas sample pool 4 to be tested. The precision spectrometer 6 is connected to a computer 7, which displays the spectral state after absorption measured by the precision spectrometer 6, thereby determining the type of gas to be tested in the first gas sample pool 4 to be tested. The precision spectrometer 6 is a spectrometer capable of resolving adjacent spectra of more than 1 nm, so that adjacent absorption spectra can be detected and distinguished.
[0038] like Figure 2 The figure shows a schematic diagram of the spectrum simulation state measured by the precision spectrometer 6 displayed by the computer 7. The spectrum of the 700-2400nm supercontinuum wide-spectrum laser before passing through the first gas sample pool 4 to be measured is shown in S1. After passing through the first gas sample pool 4 to be measured, some gas components therein absorb the laser of the corresponding wavelength. Therefore, spectral defects will be formed in the obtained spectral image, such as Figure 2 The absorption defects shown in the figure correspond to wavelengths of approximately 761 nm, 1278 nm, 1520.1 nm, 1530 nm, 1653.7 nm, 1578 nm, 1620 nm, 1742 nm and 2122.0 nm, respectively. The types of gases can be determined based on the corresponding wavelengths, and the gas types include oxygen, hydrogen fluoride, acetylene, ammonia, methane, hydrogen sulfide, ethylene, hydrogen chloride and hydrogen.
[0039] The present application can determine the type of mixed gas in the first gas sample pool 4 to be tested by passing a supercontinuum wide-spectrum laser of 700-2400nm through the first gas sample pool 4 to be tested at one time. The measurement method is simple and efficient, and can greatly improve the detection efficiency for the type detection of multiple mixed gases of 9 or even more gas types.
[0040] Step S106: The second continuous wide-spectrum laser beam is input into the tunable grating 9 through the 45-degree reflector 8. Under the control of the computer 7, the tunable grating 9 selects at least one laser beam of a preset wavelength for transmission, where the preset wavelength corresponds to the type of the gas to be measured. The transmitted laser beam is focused into the second gas sample cell 12 to be measured via the third focusing lens 10. After being absorbed by the gas to be measured, the transmitted laser beam focused into the second gas sample cell 12 is input into the laser absorption device 15 via the fourth focusing lens 13. A first detector 11 and a second detector 14 are provided to respectively measure the intensity of the transmitted laser beam before and after input into the second gas sample cell 12, and the measurement results are input into the computer 7. The transmitted laser beam is a narrow-linewidth laser beam.
[0041] The first gas sample pool 4 and the second gas sample pool 12 are identical, including the composition, volume, sample pool length, cross-sectional area, etc. of the mixed gas, so that the two measurements are equivalent to measuring the same mixed gas and obtaining accurate measurement results.
[0042] In some embodiments, the first focusing mirror and the third focusing mirror are plano-convex lenses with a focal length of 200 mm, which are used to focus the detection laser to the center position of the first gas sample pool 4 and the second gas sample pool 14 to be tested, respectively, so that the gas fully absorbs the corresponding wavelength.
[0043] If, in step S104, it is determined that the gas types in the mixed gas are oxygen, hydrogen fluoride, acetylene, ammonia, methane, hydrogen sulfide, ethylene, hydrogen chloride, and hydrogen, and their corresponding wavelengths are 761 nm, 1278 nm, 1520.1 nm, 1530 nm, 1653.7 nm, 1578 nm, 1620 nm, 1742 nm, and 2122.0 nm, respectively, then the computer 7 can output a control instruction to adjust the position of the adjustable grating, thereby outputting at least one wavelength. For each wavelength, the second gas sample cell 12 is input to detect the corresponding gas concentration. The first detector 11 and the second detector 14 respectively measure the intensity of the laser light transmitted at that wavelength before and after input into the second gas sample cell 14, thereby calculating the concentration of the gas corresponding to that wavelength.
[0044] Optionally, the first detector 11 and the second detector 14 may be power meters. Under the control of the computer 7, the tunable grating 9 outputs one wavelength at a time. The power meter measures the power of the laser light transmitted at that wavelength before and after it is input into the second gas sample cell 12 to calculate the concentration of the gas corresponding to that wavelength. Then, under the control of the computer 7, the tunable grating 9 outputs another wavelength. The power meter measures the intensity of the laser light transmitted at that wavelength before and after it is input into the second gas sample cell 12 to calculate the concentration of the gas corresponding to that wavelength. This process continues in this manner until all wavelengths determined in step S104 have been measured, ultimately determining the concentrations of all gases in the mixed gas.
[0045] Optionally, the first detector 11 and the second detector 14 may be spectrometers. Under the control of the computer 7, the adjustable grating 9 outputs one or more wavelengths at a time. The spectrometer measures the contrast of the spectral intensities of the laser light transmitted at each wavelength before and after input into the second gas sample cell 12 to calculate the concentration of the gas corresponding to that wavelength. This process is repeated one or more times until all wavelengths determined in step S104 are measured, ultimately determining the concentration of all gases in the mixed gas.
[0046] In some embodiments, the second beam of continuous wide-spectrum laser light passes through multiple beam splitters 4 and is simultaneously input into multiple adjustable gratings 9. The multiple adjustable gratings 9 select a laser of a preset wavelength for transmission under the control of the computer 7. The multiple adjustable gratings 9 output multiple transmitted laser light of corresponding wavelengths. The multiple transmitted laser light of corresponding wavelengths are respectively focused into multiple second gas sample pools 12 to be tested. Multiple first detectors and multiple second detectors are provided to respectively measure the intensity of the transmitted laser light before and after input into the second gas sample pool 12 to be tested, and the measurement results are input into the computer 7.
[0047] like Figure 3As shown, the measurement unit for measuring gas concentration in measurement step S106 has n paths, where n is greater than or equal to 9, for example, 10 or more paths: the second continuous broad-spectrum laser beam is divided into n measurement light paths by a 45-degree beam splitter 4. The measurement laser beams in the n measurement light paths are respectively input into an adjustable grating 9. Under the control of the computer 7, the n adjustable gratings 11 respectively and simultaneously select one or more preset wavelengths for transmission. The preset wavelengths correspond to the types of gases to be measured. The transmitted laser beams of multiple wavelengths are respectively input into the second gas sample cells 12 to be measured for synchronous detection. A first detector 11 and a second detector 14 are provided to respectively measure the intensity of the transmitted laser beam before and after entering each second gas sample cell 12 to be measured, and the measurement results are input into the computer 7. This embodiment places lower performance requirements on the adjustable gratings 9. Each adjustable grating 9 only needs to be able to output a single wavelength. Through software control, multiple adjustable gratings 9 cooperate to complete mixed gas detection at one time, thereby improving detection efficiency and reducing the performance requirements of the adjustable gratings.
[0048] Step S108 : the computer 7 calculates the concentration of the corresponding absorption gas according to the measurement results of the first detector 11 and the second detector 14 .
[0049] The concentration P of the absorbed gas is calculated as follows:
[0050] P=(2πSλ) / (LhB)
[0051]
[0052] P is the concentration of the gas to be measured, λ is the absorption peak wavelength of the gas to be measured, S is the area enclosed by the gas absorption peak, B is the gas absorption transition constant, L is the length of the gas sample cell to be measured, h is Planck's constant, I(ω) is the outgoing laser intensity, and I0(ω) is the incident laser intensity.
[0053] In some embodiments, the continuous broadband laser light source 1 includes a 1310nm femtosecond laser 1-1, a coupling system 1-2 and a photonic crystal fiber 1-3. The 1310nm femtosecond laser 1-1 serves as a pump source for a 700-2400nm laser light source. The laser it emits enters the photonic crystal fiber 1-3 through the coupling system 1-2. The femtosecond laser excites the photonic crystal fiber 1-3 to produce multi-order nonlinear effects, thereby generating a 700-2400nm fiber laser output.
[0054] The present invention provides a method for synchronously detecting the concentration of mixed gases based on a continuous wide-spectrum laser light source. The method adopts a continuous wide-spectrum laser light source for detection, and can simultaneously detect the types and concentrations of multiple gases in the mixed gas, thereby improving the detection efficiency of the mixed gas.
[0055] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. References to the common and similar parts between the various embodiments will be sufficient. For the systems or devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, their descriptions are relatively simple; for relevant details, refer to the descriptions of the methods.
[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. A method for synchronously detecting the concentration of mixed gases based on a continuous wide-spectrum laser light source, characterized in that: The steps include: A continuous broadband laser light source (1) is divided into two continuous broadband laser beams after passing through a beam splitter (2), wherein the first continuous broadband laser beam is transmitted along the original optical path, and the second continuous broadband laser beam is transmitted perpendicular to the original optical path; wherein the continuous broadband laser light source (1) is a supercontinuum laser light source with an output wavelength of 700-2400nm; the beam splitter (2) is a 45-degree flat mirror coated with a 50% transmission film system and a 50% reflection film system of 700-2400nm, and is used to equally split the laser input to the beam splitter (2); The first beam of continuous wide-spectrum laser light is focused into a first gas sample pool (4) to be measured via a first focusing mirror (3); the laser light focused into the first gas sample pool (4) is absorbed by the gas to be measured and then input into a precision spectrometer (6) via a second focusing mirror (5); the precision spectrometer (6) is used to detect an absorption spectrum after passing through the first gas sample pool (4); the precision spectrometer (6) is connected to a computer (7); and the type of the gas to be measured in the first gas sample pool (4) to be measured can be determined via the computer (7); The second continuous wide-spectrum laser beam is input into the adjustable grating (9) through a 45-degree reflector (8). The adjustable grating (9) selects at least one laser beam of a preset wavelength for transmission under the control of the computer (7). The preset wavelength corresponds to the type of the gas to be measured. The transmitted laser beam is focused into the second gas sample pool (12) to be measured through a third focusing mirror (10). The transmitted laser beam focused into the second gas sample pool (12) to be measured is absorbed by the gas to be measured and then input into the laser absorption device (15) through a fourth focusing mirror (14). A first detector (11) and a second detector (14) are provided to respectively measure the intensity of the transmitted laser beam before and after input into the second gas sample pool (14) to be measured, and the measurement results are input into the computer (7). The computer (7) calculates the concentration of the corresponding absorption gas based on the measurement results of the first detector (11) and the second detector (14).
2. The method according to claim 1, characterized in that The gas types are oxygen, hydrogen fluoride, acetylene, ammonia, methane, hydrogen sulfide, ethylene, hydrogen chloride and hydrogen.
3. The method according to claim 1, characterized in that The preset wavelengths are 761 nm, 1278 nm, 1520.1 nm, 1530 nm, 1653.7 nm, 1578 nm, 1620 nm, 1742 nm and 2122.0 nm.
4. The method according to claim 1, wherein The first focusing lens (3) and the third focusing lens (10) are plano-convex lenses with a focal length of 200 mm, and are used to focus the detection laser onto the center positions of the first gas sample pool (4) and the second gas sample pool (12) to be tested, respectively.
5. The method according to claim 1, wherein The first gas sample pool (4) to be tested and the second gas sample pool (12) to be tested are completely identical.
6. The method according to claim 1, characterized in that The first detector (11) and the second detector (14) are power meters and / or spectrometers.
7. The method according to claim 1, characterized in that The second continuous wide-spectrum laser beam passes through a plurality of beam splitters (4) and is simultaneously input into a plurality of adjustable gratings (9). The plurality of adjustable gratings (9) select a laser beam of a preset wavelength for transmission under the control of the computer (7). The plurality of adjustable gratings (9) output a plurality of transmitted laser beams of corresponding wavelengths. The plurality of transmitted laser beams of corresponding wavelengths are respectively focused into a plurality of second gas sample pools to be tested (12). A plurality of first detectors (11) and a plurality of second detectors (14) are provided to respectively measure the intensity of the transmitted laser beam before and after the transmission into the second gas sample pool to be tested (12), and the measurement results are input into the computer (7).
8. The method according to claim 1, characterized in that The concentration of the absorbed gas satisfies the following relationship: P=(2πSλ) / (LhB) P is the concentration of the gas to be measured, λ is the absorption peak wavelength of the gas to be measured, S is the area enclosed by the gas absorption peak, B is the gas absorption transition constant, L is the length of the gas sample cell to be measured, h is Planck's constant, I(ω) is the outgoing laser intensity, and I0(ω) is the incident laser intensity.
9. The method according to claim 1, characterized in that The continuous broadband laser light source (1) comprises: a 1310nm femtosecond laser (1-1), a coupling system (1-2) and a photonic crystal fiber (1-3); the 1310nm femtosecond laser excites the photonic crystal fiber (1-3) to generate multi-order nonlinear effects, thereby generating a 700-2400nm continuous broadband laser output.
10. The method according to claim 1, characterized in that The transmitted laser is a narrow linewidth laser.