Air pollution gas concentration monitoring system based on quantum cascade laser absorption spectrum

Abstract

According to the air pollution gas concentration monitoring system based on the quantum cascade laser absorption spectrum, a gas inlet of a first gas chamber is connected to a gas inlet pump through a pipeline I, and a gas outlet of the first gas chamber is connected to a gas inlet of a second gas chamber through a pipeline II; an air outlet of the second air chamber is connected to an exhaust pump through a pipeline III; the industrial personal computer is used for controlling the electromagnetic valve, the air inlet pump and the exhaust pump to work, the control output end of the industrial personal computer outputs a control command to the control input end of the quantum cascade laser, and the input end of the industrial personal computer is connected to the output end of the sensor module and the output end of the laser detector; the industrial personal computer is in communication connection with the monitoring center through the transmission module; two opposite light passing ports are formed in the two opposite side walls of the second gas chamber, the light passing ports are provided with optical fiber connectors, the optical signal output end of the quantum cascade laser is connected to one optical fiber connector through an optical fiber, and the optical signal input end of the laser detector is connected to the other optical fiber connector through an optical fiber.

Description

Technical Field

[0001] The utility model relates to an air detection system, in particular to an air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy. Background Art

[0002] As environmental pollution becomes increasingly serious, it is necessary to monitor the concentration of pollutant gases in the atmosphere, especially in chemical parks, where the exhaust gas emitted contains pollutants such as CO and SO2. If the concentration of these pollutants cannot be accurately monitored, accurate environmental treatment measures cannot be taken.

[0003] In the existing technology, there are the following methods for monitoring atmospheric pollutants: manually collecting sample gas with the help of corresponding instruments, and then taking it to the laboratory for analysis. This method is affected by human factors, the transportation process and the properties of the gas itself, which leads to inaccurate monitoring results. With the development of technology, online monitoring methods have been proposed. For example, corresponding sensors are used to monitor the concentration of pollutants in the atmosphere. However, due to external interference such as air flow rate and wind direction, serious errors will be caused. Moreover, as the probes of these sensors are used for a period of time, the adhesion of dust will also cause increased errors, and accuracy cannot be guaranteed.

[0004] Spectral analysis systems and methods based on lasers have also been proposed with the development of technology. For example, quantum cascade lasers and laser detectors are used to monitor sample gases. Different gases have different absorption lines of the laser spectrum, thereby forming corresponding spectral information. Concentration analysis is performed based on the spectral information. This method is efficient and its accuracy can be guaranteed. However, this method is basically completed in the laboratory and still requires sample gas collection, which results in the above-mentioned defect of manually collecting sample gas with the help of instruments.

[0005] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. Utility Model Content

[0006] In view of this, the purpose of the utility model is to provide an air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy, which can use quantum cascade lasers to monitor the concentration of pollutant gases in the air in actual sites, effectively ensuring the impact of the final monitoring results, without the need to be carried out in a laboratory, and can avoid the influence of environmental factors such as air flow rate and wind direction. The system structure is simple and easy to use.

[0007] The utility model provides an air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy, which includes a box, an air intake pump, an exhaust pump, a quantum cascade laser, a laser detector and a control unit. A first air chamber and a second air chamber are provided in the box. The air inlet of the first air chamber is connected to the air intake pump through a pipe I, the air outlet of the first air chamber is connected to the air inlet of the second air chamber through a pipe II, and the air outlet of the second air chamber is connected to the exhaust pump through a pipe III. The pipes I, II and III are all provided with solenoid valves.

[0008] The control unit includes an industrial computer, a sensor module and a transmission module;

[0009] The industrial computer is used to control the operation of the solenoid valve, the intake pump, and the exhaust pump. The control output terminal of the industrial computer outputs control commands to the control input terminal of the quantum cascade laser. The input terminal of the industrial computer is connected to the output terminal of the sensor module and the laser detector. The industrial computer is connected to the monitoring center through the transmission module.

[0010] Two opposite light ports are provided on the opposite side walls of the second air chamber, each of which is provided with a fiber optic connector. The optical signal output end of the quantum cascade laser is connected to one of the fiber optic connectors through an optical fiber, and the optical signal input end of the laser detector is connected to the other fiber optic connector through an optical fiber.

[0011] Furthermore, a filter screen is provided at the output end of the first air chamber, and the filter screen includes a first filter screen and a second filter screen;

[0012] The first filter screen and the second filter screen are arranged in sequence along the airflow direction. The first filter screen is used to filter out moisture in the air. The second filter screen includes at least two layers, and the mesh size of each layer of the second filter screen gradually increases along the airflow direction.

[0013] Furthermore, the side wall of the first air chamber provided with the air outlet is recessed outward to form a sinking cavity, the filter is arranged in the sinking cavity, and the air outlet of the first air chamber is arranged at the bottom of the sinking cavity.

[0014] Furthermore, the sensor module includes a temperature sensor, a humidity sensor and two air pressure sensors; the temperature sensor and the humidity sensor are both arranged in the second air chamber, one air pressure sensor is arranged in the second air chamber, and the other air pressure sensor is arranged outside the box.

[0015] Furthermore, the control unit further includes a location module, which is connected to the industrial computer and is used to obtain location information of the current monitoring point.

[0016] Furthermore, the transmission module is a wireless transmission module.

[0017] Furthermore, the monitoring center includes a monitoring host and a touch display, the monitoring host is communicatively connected to the touch display, and the monitoring host is communicatively connected to the industrial computer.

[0018] Furthermore, the outer side wall of the box is provided with a light-shielding and radiation-proof layer.

[0019] The beneficial effects of the present invention are as follows: through the function of the two-stage air chamber in the present invention, the sample gas collected in real time can enter the first air chamber for expansion and deceleration, and then enter the second air chamber through the filter. After filtering out most of the moisture and solid particles in the air, the concentration of the target gas is accurately detected, avoiding the influence of wind speed and wind direction, reducing the influence of moisture on accuracy, and effectively improving the accuracy of the final monitoring results.

[0020] Moreover, the structure of the present invention enables gas concentration detection based on quantum cascade lasers to be applied in on-site industrial environments without entering a laboratory, thereby reducing interference from human factors on the sample gas and further ensuring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0022] Figure 1 It is a structural diagram of the present utility model.

[0023] Figure 2 This is a schematic diagram of the electrical structure of the utility model. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below:

[0025] The utility model provides an air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy, comprising a box 2, an air intake pump 1, an exhaust pump 12, a quantum cascade laser 17, a laser detector 9 and a control unit. A first air chamber 5 and a second air chamber 11 are provided in the box 2. The air inlet of the first air chamber is connected to the air intake pump through a pipe I 4, the air outlet of the first air chamber is connected to the air inlet of the second air chamber through a pipe II 20, and the air outlet of the second air chamber is connected to the exhaust pump through a pipe III 13. The pipes I, II and III are all provided with solenoid valves (3, 19, 14);

[0026] The control unit includes an industrial computer, a sensor module and a transmission module;

[0027] The industrial computer is used to control the operation of the solenoid valve, the intake pump, and the exhaust pump. The control output terminal of the industrial computer outputs control commands to the control input terminal of the quantum cascade laser. The input terminal of the industrial computer is connected to the output terminal of the sensor module and the laser detector. The industrial computer is connected to the monitoring center through the transmission module.

[0028] The two opposite side walls of the second air chamber 11 are provided with two directly opposite light ports, each of which is provided with a fiber optic connector (16, 10). The optical signal output end of the quantum cascade laser 17 is connected to one of the fiber optic connectors 16 via an optical fiber, and the optical signal input end of the laser detector 9 is connected to the other fiber optic connector 10 via an optical fiber. Through the above structure, the concentration of polluted gases in the air can be monitored using a quantum cascade laser in the actual field, effectively ensuring the influence of the final monitoring results, without the need to be carried out in a laboratory, and can avoid the influence of environmental factors such as air flow rate and wind direction. The system structure is simple and easy to use. Among them, the quantum cascade laser and laser detector adopt existing technology. It should be noted that for different gases, different models of lasers and laser detectors need to be selected. For example, for SO2 gas detection, this gas has absorption characteristics in the infrared spectrum range of 6.82 to 9μm wavelength, so an infrared laser and a corresponding detector are selected.

[0029] In this embodiment, a filter is provided at the output end of the first air chamber, and the filter includes a first filter 9 and a second filter;

[0030] The first filter screen 7 and the second filter screen are arranged in sequence along the airflow direction. The first filter screen is used to filter out moisture in the air. The second filter screen includes at least two layers (21, 22), and the mesh size of each layer of the second filter screen gradually increases along the airflow direction. The airflow direction is from the first air chamber to the second air chamber. Figure 1 The middle is from top to bottom. Through the above structure, the influence of moisture and solid particles in the air on the laser can be effectively reduced, thereby ensuring the accuracy of the monitoring results. Of course, the mesh number of the second filter is not the larger the better. If the mesh number is too high, it may affect the sample gas.

[0031] In this embodiment, the side wall of the first air chamber 5 with an air outlet is recessed outward to form a sinking cavity 6, the filter is arranged in the sinking cavity, and the air outlet of the first air chamber is arranged at the bottom of the sinking cavity. This structure is conducive to the arrangement of the filter, and it is also conducive to the sample gas being processed through the filter, thereby ensuring the accuracy of the final result.

[0032] In this embodiment, the sensor module includes a temperature sensor 8, a humidity sensor 15 and two air pressure sensors; the temperature sensor and the humidity sensor are both arranged in the second air chamber, one air pressure sensor 18 is arranged in the second air chamber, and the other air pressure sensor 23 is arranged outside the box, wherein the air pressure sensor located outside the box is used to obtain the ambient air pressure of the current monitoring point, and the air pressure sensor in the second air chamber obtains the air pressure in the second air chamber. When collecting sample gas, the industrial computer controls the air intake pump to work, and the solenoid valves of pipeline I and pipeline II are opened, and the solenoid valve of pipeline III is closed, so as to collect sample gas. When the second air chamber When the air pressure value is equal to the air pressure value of the environment outside the box, the solenoid valves of pipeline II and pipeline III are closed. Then, after waiting for the set time, the industrial computer controls the quantum cascade laser to work. At the same time, the industrial computer obtains the temperature and humidity signals of the second air chamber, and the laser detector converts the optical signal into an electrical signal and outputs it to the industrial computer. The industrial computer generates a spectrum according to the electrical signal output by the laser detector and calculates the concentration of the target gas according to the spectrum. Of course, the calculation process is also corrected by temperature and humidity. This calculation process is an existing technology. The industrial computer transmits the process and results to the monitoring host, and the monitoring host displays and issues warnings through the touch display.

[0033] In this embodiment, the control unit also includes a positioning module, which is connected to the industrial computer and is used to obtain the location information of the current monitoring point. The positioning module uses an existing Beidou or GPS positioning module to obtain the location information of the current monitoring point, which facilitates the formulation of subsequent environmental governance measures.

[0034] In this embodiment, the transmission module is a wireless transmission module. Using a wireless module avoids line layout and saves costs. The wireless transmission module can use an existing 5G module.

[0035] In this embodiment, the monitoring center includes a monitoring host and a touch display. The monitoring host is communicatively connected to the touch display, and the monitoring host is communicatively connected to the industrial computer.

[0036] In this embodiment, the outer wall of the box 2 is provided with a light-shielding and radiation-proof layer (not shown in the figure). Through this structure, the influence of ambient light and electromagnetic radiation in the environment on the laser and laser detector is prevented, and the accuracy of the final monitoring results is effectively ensured. The light-shielding and radiation-proof layer adopts existing materials, such as aluminum foil.

[0037] Among them, Figure 2 The dashed arrows in the figure represent optical signals.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. An air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy, characterized by: The invention comprises a housing, an air intake pump, an air exhaust pump, a quantum cascade laser, a laser detector and a control unit. The housing is provided with a first air chamber and a second air chamber. The air inlet of the first air chamber is connected to the air intake pump via a pipe I, the air outlet of the first air chamber is connected to the air inlet of the second air chamber via a pipe II, and the air outlet of the second air chamber is connected to the air exhaust pump via a pipe III. The pipes I, II and III are all provided with solenoid valves. The control unit includes an industrial computer, a sensor module and a transmission module; The industrial computer is used to control the operation of the solenoid valve, the intake pump, and the exhaust pump. The control output terminal of the industrial computer outputs control commands to the control input terminal of the quantum cascade laser. The input terminal of the industrial computer is connected to the output terminal of the sensor module and the laser detector. The industrial computer is connected to the monitoring center through the transmission module. Two opposite light ports are provided on the opposite side walls of the second air chamber, each of which is provided with a fiber optic connector. The optical signal output end of the quantum cascade laser is connected to one of the fiber optic connectors through an optical fiber, and the optical signal input end of the laser detector is connected to the other fiber optic connector through an optical fiber.

2. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 1 is characterized in that: The output end of the first air chamber is provided with a filter screen, and the filter screen includes a first filter screen and a second filter screen; The first filter screen and the second filter screen are arranged in sequence along the airflow direction. The first filter screen is used to filter out moisture in the air. The second filter screen includes at least two layers, and the mesh size of each layer of the second filter screen gradually increases along the airflow direction.

3. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 2, characterized in that: The side wall of the first air chamber provided with the air outlet is concave outward to form a sinking cavity, the filter is arranged in the sinking cavity, and the air outlet of the first air chamber is arranged at the bottom of the sinking cavity.

4. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 1 is characterized in that: The sensor module includes a temperature sensor, a humidity sensor and two air pressure sensors; the temperature sensor and the humidity sensor are both arranged in the second air chamber, one air pressure sensor is arranged in the second air chamber, and the other air pressure sensor is arranged outside the box.

5. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 1 is characterized in that: The control unit further includes a location module, which is connected to the industrial computer and is used to obtain location information of the current monitoring point.

6. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 1, characterized in that: The transmission module is a wireless transmission module.

7. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 1, characterized in that: The monitoring center includes a monitoring host and a touch display. The monitoring host is communicatively connected to the touch display, and the monitoring host is communicatively connected to the industrial computer.

8. The air pollution gas concentration monitoring system based on quantum cascade laser absorption spectroscopy according to claim 1, characterized in that: The outer side wall of the box body is provided with a light-shielding and radiation-proof layer.

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