Digital detection method for suspended particles

Abstract

This invention provides a digital detection method for suspended particles that accurately detects the number and diameter of suspended particles using a digital algorithm based on the principle of light scattering. [Solution] A small pump introduces air containing suspended particles into the measurement area. A laser-emitting component emits a laser beam perpendicular to the measurement area, generating scattered light. A photodiode then senses the scattered light and converts it into an electrical signal. Subsequently, the photodiode uses a built-in digital algorithm to divide the electrical signal into N energy intervals and cumulatively records the number of particles in each interval. By cumulatively recording the number of particles in each digital calibration distribution interval and forming a detailed data distribution, data processing and data accumulation are performed to calculate the particle size, total number of particles, and concentration value of suspended particles in each particle size range (PM1, PM2.5 or less, PM10 or less).

Description

Technical Field

[0001] The present invention relates to air quality monitoring technology, and particularly to a technical method for accurately detecting the number and particle size of suspended particles using a digital algorithm based on the principle of light scattering.

Background Art

[0002] As the interest in air pollution problems increases, the detection technology of PM (Particulate Matter) has become an important component of environmental monitoring and air purification devices. Currently widely used particle sensors are mainly based on the principle of light scattering. Suspended particles are introduced into the measurement area through an air flow path, and scattered light is generated by utilizing the interaction between the laser beam and the particles. After this scattered light is captured by a condensing device and a detector, it is converted into an electrical signal, and the particle size distribution and concentration are calculated by performing data processing.

[0003] However, in the prior art, there is a drawback that the intervals of PM1, PM2.5, and PM10 are classified only based on the threshold of energy response, and accurate information regarding the number of particles cannot be provided. Data analysis mainly focuses on particle concentration, and detailed statistics regarding the number of particles in each particle size range are lacking. Therefore, an improved technical method that can accurately detect the particle size and number distribution of suspended particles and provide more comprehensive air quality data is eagerly desired.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The main objective of this invention is to provide a digital detection method for suspended particles. The energy signal generated when suspended particles pass through a photodiode (PD) is divided into N different digital calibration distribution intervals based on the intensity and distribution of the scattered light, utilizing the principles of light scattering and digital processing technology. The number of particles in each digital calibration distribution interval is cumulatively recorded, and a detailed data distribution is formed. Data processing and data accumulation are then performed to calculate the particle size, total number of particles, and concentration value of suspended particles in each particle size range (PM1, PM2.5 or less, PM10 or less). [Means for solving the problem]

[0005] To achieve the above objective, a broad embodiment of the present invention provides a digital detection method for suspended particles. The method comprises the steps of providing a particle sensor, wherein an airflow channel, a small pump, a laser light-emitting component, and a photodiode (PD) are installed inside the particle sensor, the small pump introduces air containing suspended particles into a measurement area, the laser light-emitting component is positioned perpendicular to the measurement area and emits a laser beam, the suspended particles pass through the measurement area and generate scattered light, the photodiode (PD) captures the scattered light and converts it into an electrical signal, and the photodiode (PD) executes a digital algorithm on the suspended particles passing through the measurement area, wherein the built-in digital algorithm divides the electrical signal into N energy intervals, cumulatively records the number of particles in each interval, and calculates the following based on the digital algorithm: JPEG2026120096000002.jpg64128 Here, S(b) represents the particle size threshold of the suspended particles, N(b) represents the transit time of the suspended particles, and PSD TrimThe first step involves performing data processing and data accumulation to calculate the particle size, total number of particles, and concentration values ​​of suspended particles in each particle size range (PM1, PM2.5 or less, PM10 or less). [Brief explanation of the drawing]

[0006] [Figure 1] This is a flowchart of the digital detection method for suspended particles according to the present invention. [Figure 2] This is a schematic diagram of the particle sensor of the present invention. [Figure 3] This is a schematic diagram showing the configuration of related components of the particle sensor of the present invention. [Figure 4] This is a schematic diagram showing that the particle sensor of the present invention emits a laser beam from its laser light-emitting component and captures the scattered light with a photodiode (PD). [Figure 5] This is a cross-sectional view of the particle sensor of the present invention, and is a schematic diagram showing the arrangement relationship between the laser beam emitted from the laser light-emitting component and the photodiode (PD). [Figure 6] This is a schematic diagram showing an embodiment of the digital detection method for suspended particles according to the present invention. [Modes for carrying out the invention]

[0007] Embodiments illustrating the features and advantages of the present invention will be described in detail in the following description. The present invention can have various variations in different embodiments, all of which will not depart from the scope of the invention, and it should be understood that the description and drawings are used essentially for illustrative purposes and are not intended to limit the invention.

[0008] As shown in Figures 1 to 5, the present invention provides a digital detection method for suspended particles, comprising steps S1 and S2. In step S1, a particle sensor 1 is provided. Inside the particle sensor 1, an airflow channel 11 is installed, and a small pump 12, a laser light-emitting component 13, and a photodiode (PD) 14 are installed in the airflow channel 11. The small pump 12 introduces air containing suspended particles into the measurement area A. The laser light-emitting component 13 is positioned perpendicular to the measurement area A and emits a laser beam, generating scattered light from suspended particles passing through the measurement area A, and the photodiode (PD) 14 captures the scattered light and converts it into an electrical signal. In step S2, a digital algorithm is executed by the photodiode (PD) 14 on the suspended particles passing through the measurement area A. Using the built-in digital algorithm, the electrical signal is divided into N energy intervals, the number of particles in each interval is cumulatively recorded, and calculations are performed based on the digital algorithm, the formula being as follows. JPEG2026120096000003.jpg64128 Here, S(b) represents the particle size threshold of the suspended particles, N(b) represents the transit time of the suspended particles, and PSD TrimThis represents a correction value used to compare the particle distribution map of the standard instrument with the particle distribution map of the actually detected particles. The number of suspended PM1 particles is calculated as the sum of the number of particles in the N1 digital calibration distribution interval, the number of suspended PM2.5 or less particles is calculated as the sum of the number of particles in the N2.5 digital calibration distribution interval, and the number of suspended PM10 or less particles is calculated as the sum of the number of particles in the N10 digital calibration distribution interval. Here, N1 represents the digital calibration distribution interval of PM1 that has been calibrated in N energy intervals, N2.5 represents the digital calibration distribution interval of PM2.5 that has been calibrated in N energy intervals, and N10 represents the digital calibration distribution interval of PM10 that has been calibrated in N energy intervals. Finally, data processing and data accumulation are performed to calculate the particle size, total number of particles, and concentration value of suspended particles in each particle size range (PM1, PM2.5 or less, PM10 or less).

[0009] Step S1 provides the particle sensor 1. As shown in Figures 2 to 5, the particle sensor 1 contains an airflow channel 11, a small pump 12, a laser light-emitting component 13, and a photodiode (PD) 14. The small pump 12 introduces air containing suspended particles into the measurement area A. The laser light-emitting component 13 is positioned perpendicular to the measurement area A and emits a laser beam that passes through a light-transmitting window 15, generating scattered light from suspended particles in the measurement area A. The photodiode (PD) 14 captures the scattered light and converts it into an electrical signal. In this embodiment, the small pump 12 is a piezoelectric pump and drives the intake so that a stable airflow flows uniformly through the measurement area A. The light source of the laser beam from the laser light-emitting component 13 is wavelength-stable monochromatic parallel light or focused light with a wavelength in the range of 450 nanometers (nm) to 650 nanometers (nm).

[0010] In step S2, a digital algorithm is executed by the photodiode (PD) 14 on suspended particles passing through measurement area A. As shown in Figure 6, the built-in digital algorithm is used to divide the electrical signal into N energy intervals b, the number of particles in each interval is recorded cumulatively, and calculations are performed based on the digital algorithm, with the following formula. JPEG2026120096000004.jpg64128 Here, S(b) represents the particle size threshold of the suspended particles, N(b) represents the transit time of the suspended particles, and PSD Trim This represents a correction value used to compare the particle distribution map of the standard instrument with the particle distribution map of the actually detected particles. The following values ​​are calculated for each: The PM1 suspended particle count is the total number of particles within the N1 digital calibration distribution interval. The number of suspended particles below PM2.5 is the total number of particles within the N2.5 digital calibration distribution interval. The number of suspended particles below PM10 is the total number of particles within the N10 digital calibration distribution interval. Here, N1 represents the digital calibration distribution interval of PM1, which has been calibrated in N energy intervals. N2.5 represents the digital calibration distribution interval of PM2.5 that has been calibrated in N energy intervals. N10 represents the digital calibration distribution interval of PM10, which has been calibrated in N energy intervals. In this embodiment, taking the case of dividing the energy into 40 intervals for calibration as an example, the N1 digital calibration distribution interval corresponds to the 0-10 digital calibration distribution interval, the N2.5 digital calibration distribution interval corresponds to the 0-25 digital calibration distribution interval, and the N10 digital calibration distribution interval corresponds to the 0-40 digital calibration distribution interval. For each of the 40 energy intervals, a comparison and calibration is performed between the particle distribution map of the standard instrument and the particle distribution map actually detected using a standard aerosol sample, and the PSD is calculated. Trim Generate comparative correction values. This will allow you to select the PSD for the actually detected particle size interval. Trim The data is calibrated according to the correction values ​​to ensure the accuracy of the actually detected data.

[0011] In this way, the energy signal generated when suspended particles pass through the photodiode (PD) 14 is divided into N different digital calibration distribution intervals based on its intensity, the number of particles in each digital calibration distribution interval is cumulatively recorded, a detailed data distribution is formed, and through data processing and data accumulation, the particle size, total number of particles, and concentration value of suspended particles in each particle size range (PM1, PM2.5 or less, PM10 or less) are calculated. That is, when suspended particles pass through the photodiode (PD) 14, the intervals for PM1 particle size, PM2.5 or less, and PM10 or less are divided based on the energy response threshold. When the threshold is in the 0-10 digital calibration distribution interval, it becomes the PM1 suspended particle size; when the threshold is in the 0-25 digital calibration distribution interval, it becomes the PM2.5 or less suspended particle size; and when the threshold is in the 0-40 digital calibration distribution interval, it becomes the PM10 or less suspended particle size. Of course, the built-in digital algorithm divides the area into N different digital calibration distribution sections based on its intensity, cumulatively records the number of particles in each digital calibration distribution section, and forms a detailed data distribution. Data processing and data accumulation are then performed to calculate the number of PM1 suspended particles as the sum of the number of particles in the N1 digital calibration distribution section, the number of PM2.5 or lower suspended particles as the sum of the number of particles in the N2.5 digital calibration distribution section, and the number of PM10 or lower suspended particles as the sum of the number of particles in the N10 digital calibration distribution section. In the measurement process in which the photodiode (PD) 14 executes the digital algorithm, the cumulative particle data is updated at a frequency of at least once per second.

[0012] As described above, the present invention provides a digital detection method for suspended particles. By combining the principle of light scattering and digital processing technology, electrical signals are amplified and digitized, and based on the intensity and distribution of scattered light, they are input into a built-in algorithm, and particle distribution data is calculated using a segmentation model, outputting the exact number of PM1, PM2.5, and PM10 particles, and accurately calculating the particle size, total number of particles, and concentration values ​​of suspended particles in each particle size range.

[0013] To summarize, the present invention provides a digital detection method for suspended particles, solving the problem in the prior art that the number of suspended particles cannot be accurately calculated. When the suspended particles pass through the photodiode (PD) 14, the energy signal generated is divided into N different digital calibration distribution intervals based on its intensity, and the number of particles in each digital calibration distribution interval is cumulatively recorded, forming a detailed data distribution. Through data processing and data accumulation, the particle size, total number of particles, and concentration value of suspended particles in each particle size range (PM1, PM2.5 or less, PM10 or less) are calculated.

Explanation of Reference Numerals

[0014] 1: Particle sensor 11: Airflow channel 12: Miniature pump 13: Laser emission component 14: Photodiode (PD) 15: Light transmission window A: Measurement area b: Energy interval S(b): Threshold value of the particle size of suspended particles N(b): Passage time of suspended particles PSD Trim : Correction value for comparing the particle distribution diagram of the standard instrument with the actually detected particle distribution diagram N1: Digital calibration distribution interval of PM1 calibrated by section in N energy intervals N2.5: Digital calibration distribution interval of PM2.5 calibrated by section in N energy intervals N10: Digital calibration distribution interval of PM10 calibrated by section in N energy intervals S1, S2: Steps

Claims

1. A digital method for detecting suspended particles, A step of providing a particle sensor, wherein an airflow channel, a small pump, a laser light-emitting component, and a photodiode (PD) are installed inside the particle sensor, the small pump introduces air containing suspended particles into a measurement area, the laser light-emitting component is positioned perpendicular to the measurement area and emits a laser beam, the suspended particles pass through the measurement area and generate scattered light, the photodiode (PD) captures the scattered light and converts it into an electrical signal, The step involves executing a digital algorithm using the photodiode (PD) on suspended particles passing through the measurement area, wherein the built-in digital algorithm is used to divide the electrical signal into N energy intervals, the number of particles in each interval is recorded cumulatively, and calculations are performed based on the digital algorithm, the formula of which is as follows: Here, S(b) represents the particle size threshold of the suspended particles, N(b) represents the transit time of the suspended particles, and PSD Ｔｒｉｍ This represents a correction value for comparing the particle distribution map of the standard instrument with the particle distribution map of the actually detected particles. The number of suspended PM1 particles is calculated as the sum of the number of particles in the N1 digital calibration distribution interval, the number of suspended PM2.5 particles or less is calculated as the sum of the number of particles in the N2.5 digital calibration distribution interval, and the number of suspended PM10 particles or less is calculated as the sum of the number of particles in the N10 digital calibration distribution interval. Here, N1 represents the digital calibration distribution interval of PM1 that has been calibrated in N energy intervals, N2.5 represents the digital calibration distribution interval of PM2.5 that has been calibrated in N energy intervals, and N10 represents the digital calibration distribution interval of PM10 that has been calibrated in N energy intervals. Finally, the process involves data processing and data accumulation to calculate the particle size, total number of particles, and concentration value of suspended particles in each particle size range. A digital detection method for suspended particles, including [specific particle type].

2. The digital detection method for suspended particles according to claim 1, wherein the data processing includes amplification and digitization of electrical signals, and calculation of particle diameter, total number of particles, and concentration values ​​of suspended particles in each particle diameter range using an algorithm based on the intensity and distribution of scattered light.

3. The digital detection method for suspended particles according to claim 1, wherein the light source of the laser beam of the laser light-emitting component is wavelength-stable monochromatic parallel light with a wavelength in the range of 450 nanometers to 650 nanometers.

4. The digital detection method for suspended particles according to claim 1, wherein the airflow path is configured such that a stable airflow driven by the small pump flows uniformly through the measurement area.

5. The digital detection method for suspended particles according to claim 1, wherein in a measurement process in which the photodiode (PD) executes a digital algorithm, the accumulated particle data is updated at a frequency of once per second or more.

6. The digital detection method for suspended particles according to claim 1, wherein the digital algorithm divides an electrical signal into the N energy intervals, and the N energy intervals are calibrated using a standard aerosol sample to improve the accuracy of the measurement.

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