A multi-functional gas component concentration monitoring sensor in a tunnel and a method of use

Abstract

The application discloses a kind of multi-functional gas component concentration monitoring sensors in tunnel and use method, belong to road construction technical field.The application includes white laser emitter, 90° prism, beam splitter, dust cleaner, dispersion prism, 180° prism, dispersion light intensity detector, phase interference range finding device, data processing and sending device and guide rail.The application solves the problem that the function of the existing monitoring sensor in tunnel is single, and the cost is higher and the monitoring efficiency is lower by relying on multiple single-function sensors for monitoring;The application significantly improves the monitoring accuracy of the concentration of various gas components by full-spectrum coverage and double-data comparison to average, breaks through the limitations of traditional single-function sensors, without multiple sensor devices in parallel, significantly reduces the overall operating cost, improves monitoring efficiency.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to a multifunctional gas composition concentration monitoring sensor for tunnels and its usage method. Background Technology

[0002] In tunnel construction, the environment inside the tunnel presents severe challenges. During construction, the concentrations of harmful gases such as dust, carbon dioxide, and methane increase significantly, while oxygen concentration decreases, directly threatening the safety of workers and construction efficiency. This environment necessitates a continuous supply of fresh air from outside the tunnel and the removal of harmful gases through a ventilation system to maintain suitable air quality. However, high-powered ventilation systems consume a large amount of electricity during operation, significantly increasing construction costs and burdening project management.

[0003] Currently, the industry primarily relies on deploying multiple gas sensors within tunnels to monitor gas concentrations. When harmful gases exceed safe levels, the system promptly activates ventilation equipment. However, existing sensors suffer from limited functionality: each sensor typically only detects a specific gas (e.g., a dust sensor only monitors particulate matter concentration, and a methane sensor only detects methane), failing to cover multiple gas components simultaneously. This necessitates the installation of multiple sensor nodes, increasing equipment procurement, maintenance, and energy costs, and reducing the overall efficiency of the monitoring system. Summary of the Invention

[0004] The purpose of this invention is to provide a multifunctional gas component concentration monitoring sensor and its usage method in tunnels. By covering the full spectrum and comparing two data to obtain the average value, the monitoring accuracy of various gas component concentrations is significantly improved, breaking through the limitations of traditional single-function sensors and solving the problem of requiring multiple sensor devices to operate in parallel in the existing technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A multifunctional gas composition concentration monitoring sensor for tunnels, comprising:

[0007] The white laser emitter uses fluorescence conversion to generate white laser light, which is used to excite yellow fluorescent material with blue laser light, so that the unabsorbed blue light mixes with the fluorescence to form white light.

[0008] A 90° prism is used to refract a vertically upward white laser beam into a horizontal beam.

[0009] A beam splitter is used to split a horizontal beam into two sub-beams of equal intensity.

[0010] The dust cleaner has a built-in motor-driven brush structure to automatically clean dust from the outer surface of the protective glass before each measurement.

[0011] Dispersive prisms are used to break down a returning beam of light into polychromatic light and form a continuous spectrum;

[0012] A 180° prism, located at the reflecting end, is used to reflect the first sub-beam back to the transmitting end after propagating through the air layer.

[0013] A dispersive light intensity detector has a linear array of miniature photoresistors arranged on the surface of its screen, with different positions corresponding to different colors of light, used to detect the attenuation intensity of light at various wavelengths;

[0014] A phase interferometric ranging device is used to measure the phase difference of different colors of light caused by the difference in the refractive index of air, and to calculate the concentration of various components in the air;

[0015] A data processing and transmission device is used to integrate light intensity attenuation data and phase difference data, and calculate gas concentration by weighted averaging.

[0016] The guide rail is used to connect the transmitter and the reflector. The reflector is configured to move along the guide rail within a 0.3m travel distance to a 0.15m calibration position.

[0017] Preferably, one of the sub-beams split by the beam splitter is used to propagate through the air layer and be reflected back to the transmitter to analyze the attenuation of light during air propagation, while the other sub-beam serves as a comparison reference beam.

[0018] Preferably, the dispersive light intensity detector and the phase interferometric ranging device establish a dual-mode analysis model, specifically including:

[0019] Based on the analysis of the light absorption database, the gas composition is as follows: oxygen is in the 200-230nm band, water vapor is in the 1.3-1.5μm band, carbon dioxide is in the 4.3μm band, and methane is in the 3.3μm band.

[0020] Dust concentration was calculated by comparing the light intensity attenuation ratio at the 0.3m end position and the 0.15m calibration position of the reflector.

[0021] The final gas concentration value is the weighted average of the spectral absorbance data and the phase difference calculation results.

[0022] Preferably, the data processing and transmission device includes:

[0023] External power supply module for powering the device;

[0024] The wireless communication module is used to connect to the tunnel's WIFI network and periodically upload data to the smart construction site platform;

[0025] The Bluetooth module is used to support the mobile APP to set the device number, monitor real-time data, and trigger manual measurement.

[0026] The data cable interface is used to connect to a controller consisting of a single-chip microcomputer and relays, which automatically starts and stops the fan when the methane concentration is >1% or the dust concentration is >10mg / m³.

[0027] A method for using a multifunctional gas composition concentration monitoring sensor in a tunnel, based on such a sensor, includes the following steps:

[0028] Step 1: Install a monitoring sensor every 50m inside the tunnel. The transmitting and reflecting ends are connected via a guide rail and their positions are adjusted.

[0029] Step 2: Connect to an external power source and set a unique serial number via Bluetooth using the mobile app;

[0030] Step 3: Connect the controller's data cable when automatic fan control is required;

[0031] Step 4: After installation, conduct a trial run and upload the data to the smart construction site platform for verification.

[0032] Preferably, the step of adjusting the position of the reflecting end includes: moving the reflecting end along the guide rail to a position of 0.15m or 0.3m, and measuring the laser attenuation intensity at different distances to accurately calculate the attenuation ratio.

[0033] Preferably, the steps for testing the controller include: when the controller is connected, verifying the fan start-stop function directly on the controller; when the controller is not connected, observing data through a mobile APP.

[0034] Preferably, the data verification step includes: comparing monitoring data at different locations and time periods on the smart construction site platform to verify the reliability of dust and gas concentration measurements.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1. This invention generates white laser light using fluorescence conversion and combines it with a dual-path detection mechanism: a beam splitter divides the beam equally, one beam is reflected by the air layer and its absorptivity is analyzed for dispersion, while the other beam is used for comparison and reference. Simultaneously, a phase interferometry device measures the phase difference caused by the refractive index differences of each color of light. This dual-mode detection overcomes the limitations of traditional single-function sensors. Its beneficial effects are: by achieving full spectral coverage and averaging the two data points, it significantly improves the monitoring accuracy of various gas component concentrations and solves the problem of existing technologies requiring multiple devices in parallel.

[0037] 2. This invention uses a linear photoresistor array of a dispersive light intensity detector to analyze the attenuation intensity of each spectrum in real time, a phase interferometer to simultaneously capture the spectral phase difference, and a data processing device to fuse the two types of data into a model. Its beneficial effects are as follows: Firstly, cross-validation eliminates the error of a single detection method, making the calculation deviation of harmful gas concentration less than 2%; secondly, the data can be directly uploaded to a smart construction site platform and linked to the fan controller to achieve a closed loop of monitoring, analysis, and control, reducing ventilation energy consumption by 30%.

[0038] 3. In this invention, the dust cleaner automatically starts the brush to clean the outer surface of the protective glass before each measurement, ensuring the stability of laser transmittance in high dust environments; secondly, the reflector moves within a 0.3m range via the guide rail, realizing multi-distance attenuation measurement at the same point, which not only resists the interference of the extreme environment of the tunnel on the optical device, but also accurately distinguishes between gas absorption attenuation and dust scattering attenuation through distance difference measurement, improving the reliability of dust concentration calculation by more than 40%, and requires no manual maintenance, with strong environmental adaptability. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the sensor structure of the present invention;

[0040] Figure 2 This is a schematic diagram illustrating the sensor usage method of the present invention.

[0041] In the diagram: 1. White laser emitter; 2. 90° prism; 3. Beam splitter; 4. Dust collector; 5. Dispersion prism; 6. 180° prism; 7. Dispersion intensity detector; 8. Phase interferometric ranging device; 9. Data processing and transmission device; 10. Guide rail; 11. Sub-beam; 12. Protective glass. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] To address the issue of existing tunnel monitoring sensors having limited functionality, and the high cost and low efficiency resulting from relying on multiple single-function sensors for monitoring, please refer to [link to relevant documentation]. Figure 1-2 This embodiment provides the following technical solution:

[0044] A multifunctional gas composition concentration monitoring sensor for tunnels includes a white laser emitter 1, which generates white laser light using a fluorescence conversion method. Specifically, a blue laser excites a yellow fluorescent material, causing the unabsorbed blue laser light to mix with the fluorescence to form white light. The emitted laser beam is initially vertically upward, and after refraction by a 90° prism 2, it becomes a horizontal beam. This optical steering design ensures that the optical path is parallel to the tunnel axis, establishing a reference optical path for subsequent measurements.

[0045] The horizontal beam enters the beam splitter 3 and is divided into two sub-beams 11 of equal intensity. One sub-beam 11 passes through the protective glass 12 into the air layer, reaches the 180° prism 6 at the reflecting end, and then returns along the original path. The second sub-beam 11 serves as a reference beam and is directly input into the subsequent analysis unit. A dust cleaner 4 is installed on the outer surface of the protective glass 12. Its built-in motor-driven brush structure automatically cleans the dust on the surface of the protective glass 12 before each measurement, ensuring that the light transmittance is not less than 98%.

[0046] The returning light beam is guided by beam splitter 3 to dispersive prism 5, where it is decomposed into a continuous spectrum containing seven colors of light. This spectrum is projected onto the screen of dispersive light intensity detector 7. A linear array of miniature photoresistors is arranged on the surface of the screen, with each resistor corresponding to a specific wavelength range. The gas absorptivity is calculated by detecting the attenuation intensity of each color of light. Simultaneously, phase interferometry distance measuring device 8 measures the phase difference of each color of light in white light due to the difference in air refractive index. The concentration of each component of air is calculated and compared with the attenuation intensity measured by the photoresistors. The average value is taken, which can more accurately monitor the concentration of air components. A dual-modal analysis model is established by combining the preset gas absorptivity database: the light intensity attenuation data and the phase difference calculation results are weighted and averaged, and the gas concentration value is finally output. The gas absorptivity database includes the absorptivity of various types of gases in various wavelength bands, for example:

[0047] Oxygen (O2) absorption bands: Schumann-Runge band and Herzburg band below 200nm, with some absorption still observed in the 200nm~230nm band;

[0048] Water vapor (H2O) absorption bands: 0.71μm~0.735μm, 0.81μm~0.84μm, 1.3μm~1.5μm, 1.7μm~2.0μm, 2.4μm~3.3μm, 4.8μm~8.0μm, etc.;

[0049] Carbon dioxide (CO2) absorption bands: 2.7 μm, 4.3 μm, and 14.5 μm;

[0050] Methane absorption band: 3.3μm. The chemical bond structure enables the molecule to have multiple different vibration modes. When electromagnetic waves with a specific frequency, such as infrared rays, irradiate methane molecules, if their frequency matches the vibration frequency of the molecules, it will cause the transition of the molecular vibration energy level, thereby absorbing the infrared energy of the corresponding frequency.

[0051] Dust can be calculated by using the overall light intensity attenuation at different distances at the reflection end. The dust concentration has the greatest impact on the attenuation of light intensity.

[0052] The transmitting end and the reflecting end are connected by the upper and lower guide rails 10. The reflecting end can move within a 0.3m stroke. During normal measurement, the reflecting end is placed at the end of the guide rail 10. In the calibration mode, it can be moved to the midpoint position of 0.15m to re-measure the light beam attenuation intensity. By comparing the light intensity attenuation ratios at the two positions, the calculation accuracy of the dust concentration is significantly improved. This dynamic calibration is automatically executed once every 24 hours.

[0053] The data processing and sending device 9 integrates the data of the light intensity detector 7 and the phase interference ranging device 8, and realizes the monitoring function in the following ways:

[0054] Powered by an external power supply, with a built-in wireless module connected to the tunnel WIFI network, and data is regularly uploaded to the intelligent construction site platform;

[0055] Supports Bluetooth connection with the mobile phone APP to realize device number setting, real-time data viewing and manual measurement triggering;

[0056] When used for fan control, it is connected to a controller composed of a single-chip computer and a relay through a data cable. The controller automatically starts and stops the fan according to the methane and dust concentration thresholds monitored in real time.

[0057] Install a sensor on each side wall of the tunnel every 50m. During installation, it is necessary to ensure that the horizontal accuracy error of the guide rail 10 ≤ 0.5°. After power-on, bind a unique device number through the mobile phone APP and conduct a 48-hour commissioning test: verify the data stability through the APP when not connected to the controller; simulate a scenario of excessive harmful gases when connected to the controller to test the fan linkage response. After the test is completed, enable the regular upload function. The system collects data once every 10 minutes and automatically optimizes and calibrates parameters. The key parameters are as follows:

[0058] White laser wavelength range: 400 - 700nm

[0059] Dust concentration detection limit: 0.1mg / m³

[0060] Methane detection accuracy: ±10ppm

[0061] Data upload delay: < 3s

[0062] Device Positioning and Fixing: When installing inside the tunnel, select an installation location every 50m according to design requirements. The transmitter and receiver are connected via upper and lower guide rails 10. Securely install the device at the selected location to ensure stability and prevent measurement accuracy from being affected by vibration, collisions, or other factors during tunnel construction. During installation, pay attention to the installation accuracy of the guide rails 10 to ensure that the reflector can move smoothly along the guide rails 10. The total moving distance is 0.3m, and measurements can be taken at the middle position of 0.15m.

[0063] Numbering System: Each device connects via Bluetooth through a mobile app, where a unique number is assigned to each device. This number corresponds to its specific installation location within the tunnel, facilitating subsequent management and data identification of each device. This ensures that data from each device is accurately recorded and analyzed within the vast tunnel monitoring system.

[0064] Power Connection: Connect the device's power supply to the main power supply in the tunnel. During the connection process, strictly adhere to electrical safety regulations to ensure secure wiring and good insulation, preventing safety accidents such as leakage and short circuits. Simultaneously, considering the special nature of the tunnel construction environment, implement necessary protection for the power lines, such as conduit protection, to extend the line's lifespan and ensure a stable power supply for the device.

[0065] System connection (if automatic start / stop fan function is involved)

[0066] Data cable connection: If the device needs to be connected to the controller to form an automatic start-stop fan system, use the provided data cable to connect the device to the controller. The controller consists of a microcontroller and relays. Through microcontroller programming, it automatically controls the start and stop of the fan based on the concentration of harmful gases in the air measured by sensors. When connecting the data cable, carefully check the interface type and pin definitions to ensure correct connection and avoid system malfunctions due to incorrect connections.

[0067] Network Connection Setup: The device connects to the tunnel's Wi-Fi network using a mobile app. Follow the on-screen instructions in the app to configure the network, entering the correct Wi-Fi username and password to allow the device to access the tunnel's network. Furthermore, the app supports scheduled data uploads to a smart construction site platform or other control platforms, enabling construction personnel to remotely access monitoring data in real time and stay informed about the tunnel's air quality.

[0068] Trial Run: After the device is installed and connected correctly, a trial run should be conducted for a period of time. If the device is connected to a controller, functional tests can be performed directly on the controller to check whether the controller can accurately receive the air composition data transmitted by the device and correctly control the start and stop of the fan according to the preset program. If the device is not connected to a controller, the measurement operation can be controlled using a mobile APP. The measured data can be observed in real time on the APP interface to check the accuracy and stability of the data.

[0069] Data Verification and Analysis: During the trial run, the collected data is uploaded to the smart construction site platform or other control platforms via a mobile app. Technicians then perform detailed data analysis on the platform, comparing monitoring data from different time periods and locations to verify the reliability of the device's measurement results. For example, they observe the changes in parameters such as harmful gas concentration, humidity, and temperature measured by the device when the ventilation system is on and off inside the tunnel to determine whether they conform to actual conditions and relevant standards.

[0070] Optimization and Adjustment: Based on the data verification and analysis results, if measurement errors or other problems are found in the device, corresponding optimizations and adjustments are made. For example, check whether the emission power of the white laser emitter 1 is stable, adjust the positions of optical components such as the beam splitter 3 and the dispersive prism 5 to ensure the accuracy of the optical path; check the working effect of the dust cleaner 4, and clean the dust on the surface of the outer transparent glass in a timely manner to ensure that the laser beam can pass through the glass normally and enter the air for measurement. After multiple optimizations and adjustments to ensure that the device performance is stable and reliable, it is then put into formal use.

[0071] After installation, after a period of trial testing, if connected to a controller, test directly on the controller; if not connected to a controller, use a mobile app to control the measurement, observe the measurement data on the app, and then connect to the network to use a smart construction site platform or other control platform to control the data collection and upload, verify its reliability before putting it into use.

[0072] Working Principle: The white laser emitter 1 operates via fluorescence conversion: a blue laser excites a fluorescent material to produce white light, whose full spectrum covers the characteristic absorption bands of gases such as oxygen, water vapor, and carbon dioxide. A 90° prism 2 refracts the upward laser beam into a horizontal beam, which is then split into two sub-beams 11 by a beam splitter 3. One beam 11 passes through a protective glass 12 cleaned by a dust cleaner 4 and enters the air layer, while the other beam 11 serves as a reference beam. The dust cleaner 4 automatically removes dust with a brush before each measurement to ensure light transmittance. A 180° prism 6 returns the sub-beam 11 that has passed through the air layer along its original path. After being split by the beam splitter 3, a portion of it enters the dispersive prism 5, where it is decomposed into multi-color light and projected onto a dispersive light intensity detector 7. The dispersive light intensity detector 7 detects the attenuation intensity of each color light through linearly distributed photoresistors.

[0073] The phase interferometric ranging device 8 synchronously measures the phase difference of each color of light due to the difference in refractive index, and takes the average value by combining the attenuation data of the dispersive light intensity detector 7 to accurately calculate the gas concentration; the guide rail 10 moves the reflecting end, and distinguishes between dust attenuation and gas absorption by measuring the light intensity attenuation ratio at different distances; the data processing and transmission device 9 integrates the data of the dispersive light intensity detector 7 and the phase interferometric ranging device 8, outputs the concentration result, and uploads it to the smart construction site platform via WIFI / mobile APP; when connected to the controller, it drives the fan to start and stop in real time.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A multi-functional gas component concentration monitoring sensor in a tunnel, characterized by, include: The white laser emitter (1) uses fluorescence conversion to generate white laser, which is used to excite yellow fluorescent material with blue laser, so that the unabsorbed blue light and fluorescence are mixed to form white light; A 90° prism (2) is used to refract a vertically upward white laser beam into a horizontal beam; The beam splitter (3) is used to split the horizontal beam into two sub-beams (11) of equal intensity. The dust cleaner (4) has a built-in motor-driven brush structure for automatically cleaning dust from the outer surface of the protective glass (12) before each measurement. Dispersion prism (5) is used to decompose the returning beam into polychromatic light and form a continuous spectrum; A 180° prism (6) is located at the reflecting end and is used to reflect the first sub-beam (11) back to the transmitting end after it propagates through the air layer. The dispersive light intensity detector (7) has a micro photoresistor array linearly arranged on the surface of its screen, with different positions corresponding to different colors of light, used to detect the attenuation intensity of light at each wavelength. The phase interferometric ranging device (8) is used to measure the phase difference of various colors of light due to the difference in air refractive index and to calculate the concentration of various components of air; Data processing and transmission device (9) is used to integrate light intensity attenuation data and phase difference data, and calculate gas concentration by weighted average; A guide rail (10) is used to connect the transmitting end and the reflecting end, and the reflecting end is configured to move along the guide rail within a 0.3m stroke to a 0.15m calibration position; One of the sub-beams (11) split by the beam splitter (3) is used to propagate through the air layer and be reflected back to the transmitter to analyze the attenuation of light during air propagation. The other sub-beam (11) serves as a comparison reference beam. The dispersive light intensity detector (7) and the phase interferometric ranging device (8) establish a dual-modal analysis model, specifically including: Based on the analysis of the light absorption database, the gas composition is as follows: oxygen is in the 200-230nm band, water vapor is in the 1.3-1.5μm band, carbon dioxide is in the 4.3μm band, and methane is in the 3.3μm band. Dust concentration was calculated by comparing the light intensity attenuation ratio at the 0.3m end position and the 0.15m calibration position of the reflector. The final gas concentration value is the weighted average of the spectral absorbance data and the phase difference calculation results.

2. The multi-functional gas component concentration monitoring sensor in a tunnel according to claim 1, wherein The data processing and transmission device (9) includes: External power supply module for powering the device; The wireless communication module is used to connect to the tunnel's WIFI network and periodically upload data to the smart construction site platform; The Bluetooth module is used to support the mobile APP to set the device number, monitor real-time data, and trigger manual measurement. The data cable interface is used to connect to a controller consisting of a single-chip microcomputer and relays, which automatically starts and stops the fan when the methane concentration is >1% or the dust concentration is >10mg / m³.

3. A method for using a multi-functional gas component concentration monitoring sensor in a tunnel, based on the multi-functional gas component concentration monitoring sensor according to any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Install a monitoring sensor every 50m in the tunnel. The transmitting end and the reflecting end are connected by a guide rail (10) and the position is adjusted. Step 2: Connect to an external power source and set a unique serial number via Bluetooth using the mobile app; Step 3: Connect the controller's data cable when automatic fan control is required; Step 4: After installation, conduct a trial run and upload the data to the smart construction site platform for verification.

4. The method of claim 3, wherein the sensor is used in a tunnel. The step of adjusting the position of the reflector includes: moving the reflector along the guide rail (10) to a position of 0.15m or 0.3m, and measuring the laser attenuation intensity at different distances to accurately calculate the attenuation ratio.

5. The method of claim 3, wherein the sensor is used in a tunnel. The trial operation steps include: after the device is installed and connected correctly, a trial operation is conducted for a period of time; if the device is connected to the controller, the function test can be performed directly on the controller to check whether the controller can accurately receive the air composition data transmitted by the device and correctly control the start and stop of the fan according to the preset program; if the controller is not connected, the measurement operation is controlled by a mobile APP, and the measured data is observed in real time on the APP interface to check the accuracy and stability of the data.

6. The method of claim 3, wherein the sensor is used in a tunnel. The data verification steps include: comparing monitoring data from different locations and time periods on the smart construction site platform to verify the reliability of dust and gas concentration measurements.

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