Self-calibration laser gas concentration detection method and device based on beam splitting and light splitting

Abstract

The invention discloses a self-calibration laser gas concentration detection method and device based on beam splitting and beam splitting, and relates to the technical field of gas concentration detection.The method comprises the following steps that firstly, laser is transmitted to a beam splitter through a light transmission protection pipe; step 2, generating semi-transmission and semi-reflection on a coating contact surface of the beam splitter, and splitting the beam into two beams with the same energy; step 3, the two laser beams respectively penetrate through a lens to be collimated, one laser beam enters a standard gas chamber, and the other laser beam enters a gas chamber to be detected; 4, photoelectric detectors in the two gas chambers respectively detect energy loss conditions of laser in the corresponding gas chambers, and detection data are recorded; and 5, by taking the laser energy loss condition of the standard gas chamber as a reference, comparing the laser energy loss data of the gas chamber to be detected, and judging the gas concentration in the gas chamber to be detected. According to the self-calibration laser gas concentration detection method and device based on beam splitting and light splitting, double-path detection of the standard gas chamber and the gas chamber to be detected is adopted, and self-calibration is achieved by comparing laser energy loss.

Description

Technical Field

[0001] This invention relates to the field of gas concentration detection technology, and in particular to a self-calibrated laser gas concentration detection method and device based on beam splitting and spectral dispersion. Background Technology

[0002] In the field of methane concentration detection, commonly used sensors rely on a single detection optical path or external periodic calibration. Existing technologies suffer from the following drawbacks and shortcomings: Calibration is cumbersome; traditional sensors require periodic manual calibration using standard gases, which is complex and time-consuming, impacting detection efficiency. This is especially problematic in long-term continuous monitoring scenarios, where frequent calibration can lead to monitoring interruptions. Accuracy is easily affected by interference; single-path detection is susceptible to factors such as the stability of the laser emitter, changes in ambient temperature, and contamination of the gas chamber, leading to deviations in detection results and making it difficult to guarantee long-term detection accuracy. Summary of the Invention

[0003] The purpose of this invention is to provide a self-calibrated laser gas concentration detection method and device based on beam splitting and spectral dispersion, which solves the problems of cumbersome calibration and low detection accuracy of existing methane concentration detection devices.

[0004] To achieve the above objectives, this invention provides a self-calibrated laser gas concentration detection method based on beam splitting, comprising the following steps: Step 1: The laser is emitted from the laser emitter and transmitted to the beam splitter via the optical transmission tube; Step 2: After the laser enters the beam splitter, it undergoes partial transmission and reflection at the coated contact surface of the beam splitter, and is split into two beams of the same energy. Step 3: The two laser beams after beam splitting are collimated through lenses. One laser beam enters the standard gas chamber, and the other laser beam enters the gas chamber to be tested. The laser beams propagate along the preset optical path in the two gas chambers. Step 4: The photodetectors in the two gas chambers respectively detect the energy loss of the laser in the corresponding gas chambers and record the detection data; Step 5: Using the laser energy loss of the standard gas chamber as a benchmark, compare the laser energy loss data of the gas chamber under test to determine the gas concentration in the gas chamber under test.

[0005] Preferably, in step two, the beam splitter coating must ensure that the energy deviation between the two beams after splitting is no more than 5%.

[0006] A self-calibrated laser gas concentration detection device based on beam splitting includes a beam splitter, a standard gas chamber, a gas chamber to be tested, and a lens. The lens is disposed between the beam splitter and the standard gas chamber and between the gas chamber to be tested and the beam splitter. The beam splitter is disposed inside a light transmission tube, and the front end of the light transmission tube is connected to a laser emitting end.

[0007] Preferably, the beam splitter is composed of two triangular prisms joined together, with a coating disposed between the two triangular prisms.

[0008] Preferably, the coating adopts a 5-layer symmetrical film system of SiO2-TiO2-SiO2-TiO2-SiO2, with physical thicknesses of 108nm, 69nm, 108nm, 69nm, and 108nm for each layer.

[0009] Preferably, both the standard gas chamber and the gas chamber to be tested are equipped with photodetectors, and the near-light end of each gas chamber is provided with a light-transmitting window.

[0010] Preferably, the laser emitter and the beam splitter are located on the same horizontal line; the lens located at the front end of the gas chamber under test is located on the same horizontal line as the beam splitter; and the lens located at the front end of the standard gas chamber is perpendicular to the beam splitter.

[0011] Therefore, the present invention employs the above-mentioned self-calibrated laser gas concentration detection method and apparatus based on beam splitting and spectral dispersion, which has the following beneficial effects: (1) It realizes the self-calibration function, eliminating the need for manual periodic calibration. Through real-time comparison between the built-in standard gas chamber and the gas chamber to be tested, it can dynamically eliminate system errors and ensure the accuracy and reliability of long-term testing.

[0012] (2) High detection accuracy. The beam splitter design ensures that the energy of the two detection lasers is consistent. Based on the same light source, it effectively avoids the comparison deviation caused by light source fluctuations and optical path differences, thus improving the detection accuracy.

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an embodiment of a self-calibrated laser gas concentration detection device based on beam splitting and spectral dispersion according to the present invention; Figure 2 This is a schematic diagram of the beam splitter structure of a self-calibrating laser gas concentration detection device based on beam splitting and beam splitting according to the present invention;

[0015] Figure Labels 1. Laser emitter; 2. Beam transmission tube; 3. Lens; 4. Standard gas chamber; 5. Beam splitter; 6. Photodetector; 7. Gas chamber under test; 8. Right-angle prism; 9. Coating. Detailed Implementation

[0016] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0018] Example Please see Figures 1-2 The present invention provides a self-calibrated laser gas concentration detection device based on beam splitting, including a beam splitter 5, a standard gas chamber 4, a gas chamber to be tested 7, and a lens 3. The lens 3 is disposed between the beam splitter 5 and the standard gas chamber 4 and between the gas chamber to be tested 7 and the beam splitter 5. The beam splitter 5 is disposed inside the light transmission tube 2, and the front end of the light transmission tube 2 is connected to the laser emitting end 1.

[0019] Beam splitter 5 is formed by splicing two triangular prisms to create a right-angle prism 8. A coating 9 is placed between the two triangular prisms. The coating has semi-transparent and semi-reflective properties, which can split the incident laser into two beams of equal energy. The coating 9 must ensure that the energy deviation between the two beams after splitting is ≤5%. The coating 9 adopts a 5-layer symmetrical film system of SiO2-TiO2-SiO2-TiO2-SiO2, with physical thicknesses of 108nm, 69nm, 108nm, 69nm, and 108nm, respectively, which can achieve 50:50 beam splitting.

[0020] Both the standard gas chamber 4 and the gas chamber under test 7 are equipped with photodetectors 6, and each gas chamber has a light-transmitting window at its near-light end. Both gas chambers must be kept sealed to prevent gas leakage from affecting detection accuracy. By setting up the standard gas chamber 4 and the gas chamber under test 7, the laser energy loss is detected separately using the photodetectors 6, and self-calibration is achieved using the data from the standard gas chamber 4 as a benchmark.

[0021] The laser emitter 1 and the beam splitter 5 are located on the same horizontal line. The lens 3, located at the front end of the gas chamber 7 under test, is also located on the same horizontal line as the beam splitter 5. The lens 3, located at the front end of the standard gas chamber 4, is perpendicular to the beam splitter 5. The lens 3 is positioned between the beam splitter 5 and the gas chamber to collimate the split laser beam, ensuring that the laser enters the gas chamber perpendicularly with a stable optical path.

[0022] A self-calibrated laser gas concentration detection method based on beam splitting includes the following steps: Step 1: The laser is emitted from the laser emitter 1. The laser emitter 1 needs to provide a stable wavelength laser output, which is transmitted to the beam splitter 5 through the optical transmission tube 2.

[0023] Step 2: After the laser enters the beam splitter 5, it undergoes partial transmission and reflection at the contact surface of the coating 9 of the beam splitter 5, and is split into two beams of the same energy.

[0024] Step 3: The two split laser beams are collimated through lens 3. One laser beam enters the standard gas chamber 4, and the other enters the test gas chamber 7. The laser beams propagate along a preset optical path within the two gas chambers. The two gas chambers must be kept sealed to prevent gas leakage from affecting the detection accuracy.

[0025] Step 4: The photodetectors 6 in the two gas chambers detect the energy loss of the laser in the corresponding gas chambers and record the detection data.

[0026] Step 5: Using the laser energy loss of standard gas chamber 4 as a benchmark, standard gas chamber 4 is pre-filled with methane gas at a concentration of 2%. The laser energy loss data of the test chamber 7 is compared. If the energy losses of the two are consistent, the methane concentration in the test chamber 7 is determined to be 2%; if the energy losses of the two are inconsistent, the methane concentration in the test chamber 7 is determined to be non-2%, thus achieving self-calibration detection.

[0027] Therefore, this invention employs a self-calibrating laser gas concentration detection method and device based on beam splitting and spectral dispersion, achieving self-calibration functionality: no manual periodic calibration is required; through real-time comparison between the built-in 2% CH4 standard gas chamber and the gas chamber under test, system errors can be dynamically eliminated, ensuring long-term accuracy and reliability. High detection accuracy: The beam splitter design ensures consistent energy between the two detection laser beams, and based on the same light source, effectively avoids comparison deviations caused by light source fluctuations and optical path differences, improving detection accuracy. Simple and easy-to-implement structure: The core structure consists only of conventional components such as a beam splitter, standard gas chamber, and gas chamber under test, requiring no complex control modules, making it easy to manufacture and widely apply. Strong real-time response: The laser transmission and energy detection process is continuous, allowing for real-time output of comparison results, meeting rapid detection needs and suitable for scenarios sensitive to changes in methane concentration.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A self-calibrated laser gas concentration detection method based on beam splitting and spectral dispersion, characterized in that, Includes the following steps: Step 1: The laser is emitted from the laser emitter and transmitted to the beam splitter via the optical transmission tube; Step 2: After the laser enters the beam splitter, it undergoes partial transmission and reflection at the coated contact surface of the beam splitter, and is split into two beams of the same energy. Step 3: The two laser beams after beam splitting are collimated through lenses. One laser beam enters the standard gas chamber, and the other laser beam enters the gas chamber to be tested. The laser beams propagate along the preset optical path in the two gas chambers. Step 4: The photodetectors in the two gas chambers respectively detect the energy loss of the laser in the corresponding gas chambers and record the detection data; Step 5: Using the laser energy loss of the standard gas chamber as a benchmark, compare the laser energy loss data of the gas chamber under test to determine the gas concentration in the gas chamber under test.

2. The self-calibrated laser gas concentration detection method based on beam splitting and spectral dispersion according to claim 1, characterized in that: In step two, the beam splitter coating must ensure that the energy deviation between the two beams after splitting is no more than 5%.

3. A self-calibrating laser gas concentration detection device based on beam splitting and spectral dispersion, used in the self-calibrating laser gas concentration detection method based on beam splitting and spectral dispersion as described in any one of claims 1-2, characterized in that: It includes a beam splitter, a standard gas chamber, a gas chamber to be tested, and a lens. The lens is disposed between the beam splitter and the standard gas chamber and between the gas chamber to be tested and the beam splitter. The beam splitter is disposed inside the optical transmission tube, and the front end of the optical transmission tube is connected to the laser emitting end.

4. The self-calibrating laser gas concentration detection device based on beam splitting and spectral dispersion according to claim 3, characterized in that: The beam splitter is composed of two triangular prisms joined together, with a coating disposed between the two triangular prisms.

5. The self-calibrating laser gas concentration detection device based on beam splitting and spectral dispersion according to claim 4, characterized in that: The coating adopts a 5-layer symmetrical film system of SiO2-TiO2-SiO2-TiO2-SiO2, with physical thicknesses of 108nm, 69nm, 108nm, 69nm, and 108nm for each layer.

6. The self-calibrating laser gas concentration detection device based on beam splitting and spectral dispersion according to claim 5, characterized in that: Both the standard gas chamber and the gas chamber to be tested are equipped with photoelectric detectors, and the near-light end of each gas chamber is provided with a light-transmitting window.

7. The self-calibrating laser gas concentration detection device based on beam splitting and spectral dispersion according to claim 6, characterized in that: The laser emitter and the beam splitter are located on the same horizontal line. The lens located at the front end of the gas chamber under test is located on the same horizontal line as the beam splitter. The lens located at the front end of the standard gas chamber is perpendicular to the beam splitter.

Images