A device for generating fingerprint spectrum of PM2.5 particles in air

Abstract

The invention provides a device for generating a fingerprint spectrum of PM2.5 particles in the air, belonging to the technical field of environmental detection. The device comprises an air inlet pipe, an air outlet pipe, a PM2.5 splitter, an electrostatic device, a laser emitter, a laser detector and a host computer. The air inlet pipe is connected at the entrance of the PM2.5 splitter, the PM2.5 splitter is connected to the electrostatic device through a first connecting pipe, the PM2.5 splitter is used for filtering the air introduced into the electrostatic device, two high-voltage electrodes are arranged oppositely on the inner wall of the electrostatic device, the electrostatic device and a light-transmitting tube are connected through a second connecting pipe, the inner diameter of the light-transmitting tube is less than 1 mm, and the bottom end of the light-transmitting tube is connected to the air outlet pipe; the laser emitter is used for emitting a laser beam passing through the geometric center of the light-transmitting tube, the laser detector and the laser emitter are respectively arranged on both sides of the light-transmitting tube, and a PM2.5 particle fingerprint spectrum generating module is arranged in the host computer.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental detection, and in particular, relates to a device for generating a fingerprint spectrum of PM2.5 particles in the air. Background Art

[0002] Fine particulate matter, also known as fine particles, fine particles or PM2.5, refers to particles with a diameter of less than or equal to 2.5 microns in the ambient air. It can be suspended in the air for a long time, and high concentrations of PM2.5 represent more serious air pollution. Although PM2.5 is only a small part of the earth's atmospheric composition, it has an important impact on air quality and visibility. Compared with larger atmospheric particulate matter, PM2.5 has a smaller particle size, larger surface area and stronger activity. It is easy to carry toxic and harmful substances (such as heavy metals and microorganisms), and it stays in the atmosphere for a long time and is transported over a long distance. Therefore, it has a greater impact on human health and atmospheric environmental quality. With the development of society and the improvement of living standards, people are paying more and more attention to environmental health and air quality. The PM2.5 content is one of the important indicators for measuring urban air quality. PM2.5 not only causes large-scale haze disasters and serious air pollution, but also easily causes diseases such as asthma and respiratory infections, and may contain carcinogens, which pose a hazard to human health. Therefore, it is very necessary for people to detect PM2.5 when going out. At present, the main PM2.5 detection methods include weighing method, micro-oscillation balance method, β-ray method and light scattering method. The weighing method is complicated to operate and requires professionals to operate; the micro-oscillation balance method and the β-ray method can realize automatic measurement, but cannot perform real-time detection, and the instruments are expensive and large in size, which is not suitable for the civilian detection needs of ordinary individuals and families. The light scattering method detects PM2.5 by measuring the scattering principle of light by tiny particles, which is divided into turbidity method and particle counting method. The turbidity method has low detection accuracy and can only measure the total particle concentration, and cannot detect the mass concentration of PM2.5 alone. The optical particle counting method measures the particle size of the particle according to the scattered light intensity of a single particle, thereby inferring the concentration and distribution of PM2.5 particles in the gas sampling volume.

[0003] The above methods or devices can only detect the concentration of PM2.5 particles, but cannot detect the characteristics of PM2.5 particles. Summary of the invention

[0004] In view of this, the present invention provides a device for generating a fingerprint spectrum of PM2.5 particles in the air, which can solve the technical problem that the methods or devices in the prior art can only detect the concentration of PM2.5 particles but cannot detect the characteristics of PM2.5 particles.

[0005] The present invention is achieved in that:

[0006] The present invention provides a device for generating a fingerprint spectrum of PM2.5 particles in the air, which includes an air inlet pipe, an air outlet pipe, a PM2.5 splitter, an electrostatic device, a laser transmitter, a laser detector and a host computer, wherein the air inlet of the air inlet pipe introduces the air to be detected at a speed of 1 ml / s, the air inlet pipe is connected to the entrance of the PM2.5 splitter, the PM2.5 splitter is connected to the electrostatic device through the first connecting pipe, the air inlet pipe is used to introduce air, the PM2.5 splitter is used to filter the introduced air and then introduce it into the electrostatic device, and two high-voltage electrodes are arranged on the inner wall of the electrostatic device opposite to each other. The line connecting the midpoints of the two high-voltage electrodes is perpendicular to the central axis of the first connecting tube. The electrostatic device and the light-transmitting tube are connected via a second connecting tube. The inner diameter of the light-transmitting tube is less than 1 mm. The bottom end of the light-transmitting tube is connected to the air outlet pipe. The laser emitter is used to emit a laser beam through the geometric center of the light-transmitting tube. The laser detector and the laser emitter are respectively arranged on both sides of the light-transmitting tube. The laser detector includes at least one laser receiver arranged on the direct path of the laser beam. The laser detector is communicatively connected to the host computer. The host computer is provided with a PM2.5 particle fingerprint generation module in the air.

[0007] The technical effects of the device for generating a PM2.5 particle fingerprint in the air provided by the present invention are as follows: by setting two high-voltage electrodes, the particles in the air are all charged with the same charge, so that like charges repel each other, and the particles are prevented from agglomerating and affecting the generated particle fingerprint. By setting the laser emitter to emit a laser through the geometric center of the light-transmitting tube, when the particles in the air pass through the geometric center of the light-transmitting tube, the particles will scatter the laser, and the scattered laser will be received by the laser detector, forming an electrical signal and sending it to the host computer.

[0008] On the basis of the above technical solution, the device for generating a fingerprint spectrum of PM2.5 particles in the air of the present invention can also be improved as follows:

[0009] Wherein, an air dust filter is also provided at the inlet of the air inlet pipe, and the air dust filter is used to filter large particles of dust in the air.

[0010] The field strength of the electric field formed by the two high-voltage electrodes is between 2800 V / mm and 3500 V / mm, or between -2800 V / mm and -3500 V / mm.

[0011] Furthermore, the distance between the two high-voltage electrodes is between 3 cm and 5 cm.

[0012] Furthermore, two electrostatic electrodes are arranged opposite to each other on the inner wall of the second connecting tube, the distance between the two opposite electrostatic electrodes is the same as the inner diameter of the light-transmitting tube, and the two electrostatic electrodes both carry the same positive and negative charges as those forming the electric field with the two high-voltage electrodes.

[0013] The beneficial effect of adopting the above-mentioned improved scheme is: by setting the two electrostatic electrodes with the same positive and negative charges as the electric field formed by the two high-voltage electrodes, the particles in the air have the same charge as the two electrostatic electrodes. Since like charges repel each other, the particles in the air are prevented from gathering on the inner wall of the second connecting tube.

[0014] Among them, an exhaust device is also provided at the outlet of the exhaust pipe, which is used to exhaust air at a stable exhaust rate so that the air passes through the air inlet pipe, PM2.5 separator, first connecting pipe, electrostatic device, second connecting pipe and light-transmitting tube at a stable speed.

[0015] The lasers emitted by the laser emitter are multiple laser beams of different colors, and the detection capability of the laser detector matches that of the laser emitter.

[0016] The beneficial effect of adopting the above-mentioned improved solution is that by setting the laser emitted by the laser emitter to be multiple laser beams of different colors, the multiple laser beams can pass through

[0017] Furthermore, the laser receiver is a photodiode or a photomultiplier tube, which is used to receive the laser emitted by the laser transmitter and passed through the light-transmitting tube, and generate a corresponding pulse electrical signal.

[0018] Furthermore, it also includes two first lateral laser monitors and second lateral laser monitors which are 45° away from the laser detector, the laser transmitter, the laser detector, the first lateral laser monitor and the second lateral laser monitor are located in the same plane, and the geometric center of the light-transmitting tube is equidistant from the laser detector, the first lateral laser monitor and the second lateral laser monitor, and the first lateral laser monitor and the second lateral laser monitor are both provided with the same laser receiver as that provided on the laser detector.

[0019] Furthermore, the PM2.5 particle fingerprint generation module in the air provided in the host computer is used to generate the PM2.5 particle fingerprint according to the electrical signal generated by the laser receiver, and specifically performs the following steps:

[0020] Step 1, obtaining a pulse electrical signal generated by a laser receiver when no airflow passes through the light-transmitting tube as a first signal set;

[0021] Step 2, obtaining a pulse electrical signal generated by the laser receiver when air passes through the light-transmitting tube as a second signal set;

[0022] Step 3, calculating the average value of the voltages of all pulse electrical signals in the first signal set as the basic voltage value;

[0023] Step 4, deleting the pulse electrical signals whose voltages in the second signal set differ from the basic voltage value by 5% to form a third signal set;

[0024] Step 5: The third signal set generates a voltage scatter plot as a fingerprint of PM2.5 particles in the air.

[0025] Compared with the prior art, the beneficial effect of the device for generating a fingerprint spectrum of PM2.5 particles in the air provided by the present invention is: by setting two high-voltage electrodes, the particles in the air all carry the same charge, thus achieving like charges repel each other, avoiding particle agglomeration and affecting the generated particle fingerprint spectrum. A laser transmitter is set to emit a laser through the geometric center of a light-transmitting tube. When particles in the air pass through the geometric center of the light-transmitting tube, the particles will scatter the laser. The scattered laser is received by a laser detector and then forms an electrical signal to be sent to a host computer. The host computer generates a fingerprint of PM2.5 particles in the air based on the electrical signal. Since PM2.5 particles of different properties have different physical or chemical structures, the scattered laser and lateral laser generated will have differences in brightness. Therefore, a scatter plot is generated by the voltage signals generated by a large number of PM2.5 particles of the same type. These scatter plots will have characteristics corresponding to the types of PM2.5 particles. Using these scatter plots as fingerprints of PM2.5 particles in the air can solve the technical problem that the methods or devices in the prior art can only detect the concentration of PM2.5 particles but cannot detect the characteristics of PM2.5 particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0027] Figure 1 A schematic diagram of the composition of a device for generating a fingerprint spectrum of PM2.5 particles in the air provided by the present invention;

[0028] Figure 2 A schematic diagram of a second embodiment of a device for generating a fingerprint spectrum of PM2.5 particles in air provided by the present invention;

[0029] Figure 3 Schematic diagram of the path of air particles passing through

[13] ;

[0030] Figure 4 This is a schematic diagram of scattered light after the laser is blocked by particles;

[0031] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0032] 10. Air inlet pipe; 11. First connecting pipe; 12. Second connecting pipe; 121. Electrostatic electrode; 13. Light-transmitting tube; 14. Air outlet pipe; 20. PM2.5 splitter; 30. Electrostatic device; 31. High-voltage electrode; 40. Laser emitter; 41. Laser detector; 41A. First lateral laser monitor; 41B. Second lateral laser monitor; 42. Host computer. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] like Figure 1 As shown, it is an embodiment of a device for generating a fingerprint spectrum of PM2.5 particles in the air provided by the present invention. In this embodiment, it includes an air inlet pipe 10, an air outlet pipe 14, a PM2.5 separator 20, an electrostatic device 30, a laser emitter 40, a laser detector 41 and a host computer 42, wherein the air inlet of the air inlet pipe 10 passes the air to be detected at a speed of 1 ml / s, the air inlet pipe 10 is connected to the entrance of the PM2.5 separator 20, the PM2.5 separator 20 is connected to the electrostatic device 30 through the first connecting pipe 11, the air inlet pipe 10 is used to pass air, the PM2.5 separator 20 is used to filter the air passed into the electrostatic device 30, and the inner wall of the electrostatic device 30 is provided with a filter. Two high-voltage electrodes 31 are arranged opposite to each other, and the line connecting the midpoints of the two high-voltage electrodes 31 is perpendicular to the central axis of the first connecting tube 11. The electrostatic device 30 and the light-transmitting tube 13 are connected through the second connecting tube 12. The inner diameter of the light-transmitting tube 13 is less than 1 mm, and the bottom end of the light-transmitting tube 13 is connected through the outlet pipe 14. The laser emitter 40 is used to emit a laser beam through the geometric center of the light-transmitting tube 13. The laser detector 41 and the laser emitter 40 are respectively arranged on both sides of the light-transmitting tube 13. The laser detector 41 includes at least one laser receiver arranged on the direct path of the laser beam. The laser detector 41 is connected to the host computer 42 for communication, and the host computer 42 is provided with a PM2.5 particle fingerprint generation module in the air.

[0039] Among them, in the above technical solution, an air dust filter device is also provided at the entrance of the air inlet pipe 10, and the air dust filter device is used to filter large particles of dust in the air.

[0040] Wherein, in the above technical solution, the field strength of the electric field formed by the two high-voltage electrodes 31 is between 2800 V / mm and 3500 V / mm, or between -2800 V / mm and -3500 V / mm.

[0041] Furthermore, in the above technical solution, the distance between the two high-voltage electrodes 31 is between 3 cm and 5 cm.

[0042] Furthermore, in the above technical solution, two electrostatic electrodes 121 are arranged opposite to each other on the inner wall of the second connecting tube 12, and the distance between the two opposite electrostatic electrodes 121 is the same as the inner diameter of the light-transmitting tube 13. The two electrostatic electrodes 121 both carry the same positive and negative charges that form an electric field with the two high-voltage electrodes 31.

[0043] like Figure 3 As shown, the charged particles pass through the path of the light-transmitting tube 13 while avoiding the lateral disorderly movement of the particles.

[0044] Among them, in the above technical scheme, an exhaust device is also provided at the outlet of the air outlet pipe 14, which is used to exhaust air at a stable exhaust rate, so that the air passes through the air inlet pipe 10, the PM2.5 separator 20, the first connecting pipe 11, the electrostatic device 30, the second connecting pipe 12 and the light-transmitting tube 13 at a stable speed.

[0045] Among them, in the above technical solution, the laser emitted by the laser emitter 40 is a plurality of laser beams of different colors, and the detection capability of the laser detector 41 matches that of the laser emitter 40 .

[0046] Furthermore, in the above technical solution, the laser receiver is a photodiode or a photomultiplier tube, which is used to receive the laser emitted by the laser transmitter 40 and passing through the light-transmitting tube 13, and generate a corresponding pulse electrical signal.

[0047] Photodiode: When a laser photon strikes a photodiode, it ionizes the detector's atoms, creating electrons in the diode's depletion region and sweeping them toward positive and negative potentials. Photodiodes are inexpensive, but have low sensitivity, and they do not amplify photocurrent as well as photomultiplier tubes.

[0048] Photomultiplier tube: When laser photons enter the photomultiplier tube, they strike the photocathode and generate electrons, which move from the dynode to the dynode where secondary electrons are generated, amplifying the signal. Photomultiplier tubes are more sensitive to low signal levels and can amplify the energy of a single photon millions of times, which can better improve the sensitivity of detection.

[0049] Further, such as Figure 2 As shown, in the above technical solution, it also includes two first lateral laser monitors 41A and second lateral laser monitors 41B which are at 45° to the laser detector 41, the laser emitter 40, the laser detector 41, the first lateral laser monitor 41A and the second lateral laser monitor 41B are located in the same plane, and the geometric center of the light-transmitting tube 13 is at the same distance from the laser detector 41, the first lateral laser monitor 41A and the second lateral laser monitor 41B, and the first lateral laser monitor 41A and the second lateral laser monitor 41B are both provided with the same laser receiver as that provided on the laser detector 41.

[0050] Furthermore, in the above technical solution, the PM2.5 particle fingerprint generation module in the air provided in the host computer 42 is used to generate the PM2.5 particle fingerprint according to the electrical signal generated by the laser receiver, and specifically performs the following steps:

[0051] Step 1, obtaining a pulse electrical signal generated by a laser receiver when no airflow passes through the light-transmitting tube 13 as a first signal set;

[0052] Step 2, obtaining the pulse electrical signal generated by the laser receiver when air passes through the light-transmitting tube 13 as a second signal set;

[0053] Step 3, calculating the average value of the voltages of all pulse electrical signals in the first signal set as the basic voltage value;

[0054] Step 4, deleting the pulse electrical signals whose voltages in the second signal set differ from the basic voltage value by 5%, to form a third signal set;

[0055] Step 5: The third signal set generates a voltage scatter plot as a fingerprint of PM2.5 particles in the air.

[0056] When the device also includes a first lateral laser monitor 41A and a second lateral laser monitor 41B or a laser emitter 40 that emits multiple laser beams, when executing the step of generating a PM2.5 particle fingerprint spectrum from electrical signals, different laser receivers are considered separately. At the same time, the voltage scatter diagrams corresponding to the multiple laser receivers are used to generate a voltage scatter diagram set, and this voltage scatter diagram set is used as the PM2.5 particle fingerprint spectrum in the air.

[0057] Specifically, the principle of the present invention is: Figure 4 As shown, when the laser beam irradiates the PM2.5 particles in the air, forward scattered laser and side scattered laser will be generated, and the brightness of both is lower than that of the original laser beam. A photodiode or a photomultiplier tube is used to receive these forward scattered laser and side scattered laser, and convert them into voltage signals. PM2.5 particles of different properties will generate scattered laser and side laser with different brightness due to their different physical or chemical structures. Therefore, a large number of PM2.5 particles of the same type will generate voltage signals to generate scatter plots. These scatter plots will have characteristics corresponding to the types of PM2.5 particles. These scatter plots will be used as fingerprints of PM2.5 particles in the air, and a PM2.5 particle fingerprint database will be formed. According to this database, the type of PM2.5 particles in the air to be detected can be determined.

[0058] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A device for generating a fingerprint spectrum of PM2.5 particles in the air, characterized in that: The device comprises an air inlet pipe, an air outlet pipe, a PM2.5 separator, an electrostatic device, a laser emitter, a laser detector and a host computer, wherein the air inlet of the air inlet pipe introduces the air to be detected at a speed of 1 ml / s, the air inlet pipe is connected to the entrance of the PM2.5 separator, the PM2.5 separator is connected to the electrostatic device through a first connecting pipe, the air inlet pipe is used to introduce air, the PM2.5 separator is used to filter the introduced air and then introduce it into the electrostatic device, two high-voltage electrodes are arranged opposite to each other on the inner wall of the electrostatic device, the line connecting the midpoints of the two high-voltage electrodes is perpendicular to the central axis of the first connecting pipe, and the electrostatic device The light-transmitting tube is connected to the air outlet pipe through a second connecting tube, the inner diameter of the light-transmitting tube is less than 1 mm, and the bottom end of the light-transmitting tube is connected to the air outlet pipe through a connecting tube; the laser emitter is used to emit a laser beam through the geometric center of the light-transmitting tube, the laser detector and the laser emitter are respectively arranged on both sides of the light-transmitting tube, the laser detector includes at least one laser receiver arranged on the direct path of the laser beam, the laser detector is connected to the host computer for communication, and a PM2.5 particle fingerprint generation module in the air is arranged in the host computer, which is used to generate a PM2.5 particle fingerprint according to the electrical signal generated by the laser receiver, and specifically performs the following steps: Step 1, obtaining a pulse electrical signal generated by a laser receiver when no airflow passes through the light-transmitting tube as a first signal set; Step 2, obtaining a pulse electrical signal generated by the laser receiver when air passes through the light-transmitting tube as a second signal set; Step 3, calculating the average value of the voltages of all pulse electrical signals in the first signal set as the basic voltage value; Step 4, deleting the pulse electrical signals whose voltages in the second signal set differ from the basic voltage value by 5% to form a third signal set; Step 5: The third signal set generates a voltage scatter plot as a fingerprint of PM2.5 particles in the air.

2. The device for generating a fingerprint spectrum of PM2.5 particles in the air according to claim 1, characterized in that: An air dust filter is also provided at the inlet of the air inlet pipe, and the air dust filter is used to filter large dust particles in the air.

3. The device for generating a fingerprint spectrum of PM2.5 particles in air according to claim 1, characterized in that: The field strength of the electric field formed by the two high-voltage electrodes is between 2800 V / mm and 3500 V / mm, or between -2800 V / mm and -3500 V / mm.

4. The device for generating a fingerprint spectrum of PM2.5 particles in air according to claim 3, characterized in that: The distance between the two high voltage electrodes is between 3 cm and 5 cm.

5. The device for generating a fingerprint spectrum of PM2.5 particles in air according to claim 3, characterized in that: Two electrostatic electrodes are arranged opposite to each other on the inner wall of the second connecting tube, the distance between the two opposite electrostatic electrodes is the same as the inner diameter of the light-transmitting tube, and the two electrostatic electrodes both carry charges of the same positive and negative as those forming the electric field with the two high-voltage electrodes.

6. The device for generating a fingerprint spectrum of PM2.5 particles in air according to claim 1, characterized in that: An exhaust device is also provided at the outlet of the air outlet pipe, which is used to exhaust air at a stable exhaust rate so that the air passes through the air inlet pipe, PM2.5 separator, first connecting pipe, electrostatic device, second connecting pipe and light-transmitting pipe at a stable speed.

7. The device for generating a fingerprint spectrum of PM2.5 particles in air according to claim 1, characterized in that: The lasers emitted by the laser emitter are multiple laser beams of different colors, and the detection capability of the laser detector matches that of the laser emitter.

8. A device for generating a fingerprint spectrum of PM2.5 particles in air according to any one of claims 1 to 7, characterized in that: The laser receiver is a photodiode or a photomultiplier tube, which is used to receive the laser light emitted by the laser transmitter and passed through the light-transmitting tube, and generate a corresponding pulse electrical signal.

9. The device for generating a fingerprint spectrum of PM2.5 particles in air according to claim 8, characterized in that: It also includes two first lateral laser monitors and a second lateral laser monitor which are at 45° to the laser detector. The laser transmitter, the laser detector, the first lateral laser monitor and the second lateral laser monitor are located in the same plane, and the geometric center of the light-transmitting tube is at an equal distance from the laser detector, the first lateral laser monitor and the second lateral laser monitor. The first lateral laser monitor and the second lateral laser monitor are both provided with a laser receiver identical to that provided on the laser detector.

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