CN109211744B - Apparatus and method for measuring granular substance by optical method - Google Patents
Apparatus and method for measuring granular substance by optical method Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims abstract description 38
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- 238000001514 detection method Methods 0.000 claims abstract description 53
- 238000005520 cutting process Methods 0.000 claims abstract description 19
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- 238000005259 measurement Methods 0.000 claims description 42
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
- G01N15/0606—Investigating concentration of particle suspensions by collecting particles on a support
- G01N15/0618—Investigating concentration of particle suspensions by collecting particles on a support of the filter type
- G01N15/0625—Optical scan of the deposits
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- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses a device and a method for measuring granular substances by an optical method, wherein the device comprises: the collecting device is used for collecting atmosphere; the cutting head is used for cutting the atmosphere into particles with a preset particle size range; forming a gas channel for the container to enable particles cut into a preset particle size range to enter the left container and the right container respectively; the trapping device is used for trapping the filtered particles by using banded filter paper; the light source is used for alternately emitting light rays in a specific wavelength region to the strip-shaped filter paper; the detection device is used for receiving the light rays with different wavelengths emitted by the light source and detecting the reflected light and the transmitted light with different wavelengths through the detector; the processor is used for calculating the concentration of OC/EC in the particles captured on the strip-shaped filter paper through the voltage value detected by the detector. The device does not need to carry out thermal decomposition on the collected sample, does not need to carry out pretreatment to damage the sample, and has more accurate determination; no carrier gas is needed, the operation cost is reduced, and the device is simpler and more convenient.
Description
Technical Field
The invention relates to the technical field of environmental measuring instruments, in particular to a device and a method for measuring granular substances by an optical method.
Background
In recent years, the problem of atmospheric environmental pollution has attracted human attention, fog, smoke, haze and the like are atmospheric aerosols caused by natural or artificial reasons, Organic Carbon (OC) and Elemental Carbon (EC) are high-content components in the atmospheric aerosols and account for about 10% to 70% of the mass concentration of the aerosols, and the smaller the particle size of the atmospheric particulates is, the larger the proportion of the Organic Carbon (OC) and the Elemental Carbon (EC) is. Organic Carbon (OC) and Element Carbon (EC) in the atmospheric aerosol participate in the formation of photochemical smog, haze and the like, the Element Carbon (EC) has great surface activity, can adsorb harmful substances in the atmosphere, directly or indirectly influence the atmospheric environment and human health, cause regional composite pollution, influence the earth radiation balance, continuously and accurately measure the content of the Organic Carbon (OC) and the Element Carbon (EC) in the atmospheric aerosol, contribute to the research of the contribution of each emission source to the atmospheric aerosol, and have important significance for researching the source, formation and conversion mechanism of the atmospheric aerosol.
At present, the detection method aiming at OC/EC in the atmosphere is mainly a thermo-optic method. For example, (1) in the related art, the Organic Carbon (OC) concentration, the Elemental Carbon (EC) concentration, the Total Carbon (TC) concentration in the particulate matter are analyzed by a thermo-optic method using a reaction furnace and an oxidation furnace; (2) in the related technology, a graded sampler of a quartz membrane is used for sampling for at least 12 hours, a part of 1/2 quartz membrane sample is taken, cut into pieces and put into a crucible which is burnt at high temperature for weighing, high-purity iron powder is added, an infrared carbon sulfur instrument is heated, the measurement result is total carbon content TC (percentage content), and the other part of 1/2 quartz membrane sample is taken and heated to 405-445 ℃ in a muffle furnace for keeping for 5-60 minutes; analyzing the carbon content by using an infrared carbon sulfur instrument, wherein the determination result is the EC content (percentage content) of the element carbon; calculating the content of organic carbon OC in the sample by a differential subtraction method; (3) in the related technology, quartz filter membrane, combustion furnace, oxidation furnace and CO are used2Detector, laser detection unit, etc. for heating the sample in He gas environment, wherein the volatilized carbon is regarded as organic carbon, and then He/O2The temperature is raised in the carrier gas atmosphere, and the elemental carbon is oxidatively decomposed and escaped during the raising, thereby performing the measurement.
However, in the related art, the quartz film is almost used for sample collection, and the sample is pretreated by heating, oxidizing and other modes, so that the original sample detection cannot be realized, the measurement precision is influenced, the structure of the measurement device is complex, the cost of standard gas required in measurement is high, and the operation and maintenance of the device are complicated.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, an object of the present invention is to provide an optical-method particulate matter measuring apparatus.
Another object of the present invention is to provide a method for measuring a particulate matter by an optical method.
In order to achieve the above object, according to one aspect of the present invention, there is provided an optical-method particulate matter measuring apparatus comprising: the collecting device is used for collecting the atmosphere; the cutting head is used for cutting the atmosphere into particles with a preset particle size range; a container for forming a gas passage for allowing the particles cut into a predetermined particle size range to enter the left container and the right container, respectively; (ii) a A trapping device for trapping the plurality of particles in the container by using a band-shaped filter paper; a light source for alternately emitting light in a specific wavelength region to the band-shaped filter paper; the detection device is used for receiving the light rays with different wavelengths emitted by the light source and detecting the reflected light and the transmitted light with different wavelengths through the detector; and the processor is used for calculating the concentration of OC/EC in the particles captured on the strip-shaped filter paper through the voltage value detected by the detector.
According to the optical method granular substance measuring device provided by the embodiment of the invention, thermal decomposition and pretreatment of the collected sample are not required, the sample is not damaged, and the measurement is more accurate; the measuring device does not need carrier gas, so that the running cost is reduced, and the device is simpler and more convenient; and the OC/EC concentration contained in the atmospheric particulates can be measured by an optical method under the conditions of no need of sample pretreatment and no need of carrying carrier gas, and the method has the advantages of accurate measurement, low cost and simple maintenance.
In addition, the optical method particulate matter measuring apparatus according to the above embodiment of the present invention may further have the following additional features:
further, in one embodiment of the present invention, the collecting device includes: the air inlet rod is connected with the air inlet and the cutting head to form a sampling atmosphere channel.
Further, in one embodiment of the present invention, the trapping device comprises: the banded filter paper is used for trapping the particles cut into the preset particle size range; a rewinding shaft for mounting the band-shaped filter paper; a reel for winding the band-shaped filter paper of a fixed length; and the filter paper breakage inductor is used for detecting whether the strip filter paper is broken by utilizing an optical principle so as to judge whether the instrument normally operates for measurement.
Further, in one embodiment of the present invention, the container includes: the gas pumping pipeline is used for connecting the container and the pumping pump to form a gas channel; the pressure sensor is used for detecting a pressure value so as to ensure the normal operation and measurement of the device; the filter is used for filtering dust possibly existing in the suction pipeline so as to ensure that the device components work normally; the flow sensor is used for sensing the flow of the gas channel to carry out real-time monitoring; and the electromagnetic valve is used for flow control.
Further, in one embodiment of the present invention, the detection device includes a transmitted light detector for detecting transmitted light of a plurality of wavelengths received by the band pass filter, and a reflected light detector for detecting reflected light of a plurality of wavelengths received by the band pass filter.
Further, in an embodiment of the present invention, the detection of the transmitted light is the detection of a voltage value corresponding to the intensity of the transmitted light of the particulate matter, and the detection of the reflected light is the detection of a voltage value corresponding to the intensity of the reflected light of the particulate matter.
In order to achieve the above object, according to another aspect of the present invention, there is provided a method for measuring a particulate matter by an optical method, comprising the steps of: collecting atmosphere, and cutting the atmosphere into particles with a preset particle size range; forming a gas channel through the container to enable the particles cut into the preset particle size range to respectively enter the left container and the right container so as to carry out banded filter paper trapping; the light source alternately emits light rays in a specific wavelength region to the strip-shaped filter paper, the detector receives the light rays in the specific wavelength region, detects reflected light rays and transmitted light rays through the light rays in the specific wavelength region to obtain voltage values of the reflected light rays and the transmitted light rays, and calculates the concentration of OC/EC in particles captured on the strip-shaped filter paper.
According to the method for measuring the granular substances by the optical method, the collected samples do not need to be subjected to thermal decomposition and pretreatment, the samples are not damaged, and the measurement is more accurate; the measuring device does not need carrier gas, so that the running cost is reduced, and the device is simpler and more convenient; and the OC/EC concentration contained in the atmospheric particulates can be measured by an optical method under the conditions of no need of sample pretreatment and no need of carrying carrier gas, and the method has the advantages of accurate measurement, low cost and simple maintenance.
In addition, the method for measuring the granular material by the optical method according to the above embodiment of the present invention may further have the following additional technical features:
further, in an embodiment of the present invention, the filtering the particles cut into the predetermined size range into the left container and the right container respectively further includes: when the particle size of the cut particles is smaller than the preset particle size, the particles enter a left container; and when the particle size of the cut particles is larger than the preset particle size, the particles enter the right container.
Further, in an embodiment of the present invention, the detecting of the reflected light and the transmitted light by the light in the specific wavelength region further includes: detecting, with a transmitted light detector, transmitted light of a plurality of wavelengths received by the band-pass filter; a reflected light detector is used to detect reflected light in the plurality of wavelengths received by the band pass filter.
Further, in an embodiment of the present invention, the detection of the transmitted light is the detection of a voltage value corresponding to the intensity of the transmitted light of the particulate matter, and the detection of the reflected light is the detection of a voltage value corresponding to the intensity of the reflected light of the particulate matter.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic view showing the construction of an apparatus for measuring a particulate matter by an optical method according to an embodiment of the present invention;
FIG. 2 is a schematic view showing the detailed structure of an apparatus for measuring a particulate matter by an optical method according to an embodiment of the present invention;
FIG. 3 is an enlarged view of a band-shaped filter paper in an apparatus for measuring a particulate matter by an optical method according to an embodiment of the present invention;
FIG. 4 is one of the results of measurements of the decay rate of transmitted light intensity as a function of time for each measurement according to one embodiment of the present invention;
FIG. 5 is one of the results of measurements of the decay rate of reflected light intensity as a function of time for each measurement, according to one embodiment of the present invention;
FIG. 6 is one of the results of measurements of Organic Carbon (OC) concentration as a function of time for each measurement according to one embodiment of the present invention;
FIG. 7 is one of the results of measurements of inorganic carbon (EC) concentration as a function of time for each measurement according to one embodiment of the present invention;
FIG. 8 is one of the results of measurements of PM2.5 mass concentration as a function of time for each measurement, according to one embodiment of the present invention;
FIG. 9 is a correlation of light intensity with fWSOC, according to one embodiment of the present invention;
FIG. 10 shows the organic carbon concentration (. mu.gC/m) measured by the apparatus for measuring granular matters by optical method and the apparatus for measuring carbon analyzer according to one embodiment of the present invention3) Correlation;
FIG. 11 is a graph showing the inorganic carbon concentration (. mu.gC/m) measured by the apparatus for measuring a granular material and the apparatus for measuring a carbon analyzer according to one embodiment of the present invention3) Correlation;
fig. 12 is a flow chart of a method for optically determining particulate matter in accordance with one embodiment of the present invention.
Description of reference numerals:
100-optical method granular material determination device air inlet, 1-collection device, 1.1-air inlet, 1.2-air inlet rod, 2-cutting head, 3-container, 3 a-left container, 3 b-right container, 3.1-first air suction pipeline, 3.2-second air suction pipeline, 3.1.1-pressure sensor, 3.1.2-first filter, 3.2.1-second filter, 3.1.3-first flow sensor, 3.2.2-second flow sensor, 3.1.4-first solenoid valve, 3.2.3-second solenoid valve, 4-trapping device (i.e. strip filter paper), 4.1-reverse reel, 4.2-reel, 4.3-filter paper break sensor, 4.4-strip filter paper support net, 4.4.1-linear support material, 4.4.2-support mesh, 5-light source, 6-detection device, 6.1-transmission light detector, 6.2-reflection light detector, 7-processor, 7.1-first calculating part, 7.2-second calculating part, 8-composite optical fiber, 9-control device, 10-storage device, 11-suction pump and 12-box body.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
An optical-method particulate matter measuring apparatus proposed according to an embodiment of the present invention will be described below with reference to the accompanying drawings, and first, an optical-method particulate matter measuring method proposed according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a schematic structural view of an optical-method particulate matter measuring apparatus according to an embodiment of the present invention.
As shown in fig. 1, the optical-method particulate matter measurement device 100 includes: the device comprises a collecting device 1, a cutting head 2, a container 3, a trapping device 4, a light source 5, a detection device 6 and a processor 7.
Wherein the collecting device 1 is used for collecting the atmosphere. The cutting head 2 is used to cut the atmosphere into particles of a predetermined size range. The container 3 is used for forming a gas passage for allowing the particles cut into the preset particle size range to enter the left container and the right container respectively. The trap device 4 is used to trap a plurality of particles in a container by using a band-shaped filter paper. The light source 5 is used to alternately emit light in a specific wavelength region to the band-shaped filter paper. The detecting device 6 is used for receiving the light rays with different wavelengths emitted by the light source and detecting the reflected light and the transmitted light with different wavelengths through the detector. The processor 7 is used for calculating the concentration of OC/EC in the particles captured on the strip-shaped filter paper through the voltage value detected by the detector. The device 100 provided by the embodiment of the invention does not need to carry out thermal decomposition on the collected sample, does not need to carry out pretreatment to damage the sample, and is more accurate in measurement; the operation cost is reduced without carrier gas, so that the device is simpler and more convenient.
Specifically, as shown in fig. 2, the cutting head according to the embodiment of the present invention employs a PM2.5 virtual impact cutting head, and cuts the collected atmosphere into particles having a particle size of 2.5 μm or less and other particles according to the particle size (aerodynamic particle size), and the optical method particulate matter measuring apparatus according to the present invention is implemented to measure OC/EC in particles having a particle size of 2.5 μm or less, which affect human health by respirable human lungs. The light source 5 is disposed above the strip filter paper 4, the light source 5 is controlled by the control device 9 to alternately emit light rays (e.g., 378nm, 870nm) in specific first and second wavelength regions, and the light source 5 may be designed to emit a plurality of light rays of different wavelengths in a specific wavelength region or to emit light rays in third and fourth wavelength regions. Wherein the first wavelength region is 220nm-500nm, the second wavelength region is 650nm-1000nm, the third wavelength region is 400nm-600nm, and the fourth wavelength region is 200nm-300 nm. The Light source 5 of the embodiment of the present invention has an LED (Light Emitting Diode) capable of Emitting Light in the first and second wavelength regions, and an LED capable of Emitting Light in the third and fourth wavelength regions may be configured as needed, and besides the LED, the Light source 5 may also use a xenon lamp or the like to emit Light in different wavelength regions. The processor 7 is realized by a computer (PC) and comprises two calculating parts, wherein the first calculating part 7.1 is connected with the transmission light detector 6.1 and the reflection light detector 6.2, the second calculating part 7.2 is connected with the reflection light detector 6.2, and the OC/EC concentration in the particles collected on the strip-shaped filter paper 4 is calculated through the voltage value detected by the detectors.
Further, in one embodiment of the present invention, the collecting apparatus 1 includes: an air inlet 1.1 and an air inlet rod 1.2, wherein the air inlet rod 1.2 connects the air inlet 1.1 with the cutting head to form a sampling atmosphere channel.
Further, as shown in FIG. 2, a PM10 inlet was used as the inlet, and the sampled air (particle size of particulate matter is 10 μm or less) was introduced into the apparatus through the inlet.
Alternatively, in one embodiment of the present invention, the trapping device 4 comprises: a band-shaped filter paper 4 for trapping particles cut into a predetermined particle size range; a rewinding shaft 4.1 for mounting the banded filter paper; a reel 4.2 for taking up a band-shaped filter paper of a fixed length; and the filter paper breakage inductor 4.3 is used for detecting whether the strip filter paper is broken by utilizing an optical principle so as to judge whether the filter paper works normally.
As shown in fig. 2 to 3, the strip filter paper 4 according to the embodiment of the present invention is made of teflon, has a shape of a thin film paper tape, and collects the cut sampling air. The rewind shaft 4.1 is also the driven shaft in addition to being used for mounting the strip-shaped filter paper. The reel 4.2 connects the device to a motor (not shown) driving the reel in rotation, the motor being connected to a power supply, the motor being rotated by a fixed number of revolutions at fixed time intervals by an operating command from the control power supply, so that the reel takes up a fixed length of band-shaped filter paper. The filter paper breakage sensor 4.3 detects whether the strip filter paper is broken by using an optical principle so as to judge whether the device normally operates for measurement.
As shown in fig. 2 and 4, the trap device 4 further includes a strip-shaped filter paper support net 4.4, linear support members 4.4.1, and support meshes 4.4.2 for supporting the strip-shaped filter paper 4, wherein the strip-shaped filter paper support net 4.4 is formed by a plurality of linear members arranged in a grid pattern, meshes are arranged between the linear support members 4.4.1, and when a filter paper pressing module (not shown) is in a raised state, the strip-shaped filter paper can be continuously moved, and when the filter paper pressing module is in a pressed state, the strip-shaped filter paper cannot be moved.
Further, in one embodiment of the present invention, the container 3 includes: the gas pumping pipeline is used for connecting the container and the pumping pump 11 to form a gas channel; the pressure sensor is used for detecting a pressure value so as to ensure the normal operation and measurement of the device; the filter is used for filtering dust possibly existing in the air suction pipeline so as to ensure that the device parts work normally; the flow sensor is used for sensing the flow of the gas channel to carry out real-time monitoring; and the electromagnetic valve is used for flow control.
Specifically, as shown in fig. 2-3, in the embodiment of the present invention, the container is a square box-shaped structure made of metal, and is connected to a cutting head, small particles (less than 2.5 μm) cut by the cutting head enter a left container, large particles enter a right container, and are trapped by a strip-shaped filter paper; the lower end of the container is connected with an air pumping pipeline. The air pumping pipeline is connected with the container and the pumping pump to form an air passage. The pressure sensor senses the pressure in the pipeline, the measuring device of the invention sets a certain pressure value and sampling time, when the content of atmospheric particulate matters is higher, the sampling time is less than a set value, and the pressure is greater than the set value, the device can reset the filter paper, the filter paper is rolled to ensure the normal operation measurement of the device, and the measurement result can be ensured to be more accurate. The filter is positioned in the suction pipeline and is used for filtering dust possibly existing in the pipeline so as to ensure that the device parts work normally. The flow inductor is positioned in the air suction pipeline and induces the flow in the air path so as to realize real-time monitoring of the flow in the flow path. In addition, an electromagnetic valve is arranged in the air extraction pipeline and is used for flow control.
Further, in an embodiment of the invention, the detection means 6 comprises a transmitted light detector 6.1 and a reflected light detector 6.2, wherein the transmitted light detector 6.1 is arranged to detect transmitted light of the plurality of wavelengths received by the band-pass filter, and the reflected light detector 6.2 is arranged to detect reflected light of the plurality of wavelengths received by the band-pass filter.
Specifically, as shown in fig. 2, the transmitted light detector 6.1 is composed of a silicon photodiode, a photomultiplier tube, a multi-spectrometer having a light resolving function, and the like, and detects a voltage value (mV) corresponding to the intensity of transmitted light of the particulate matter. The transmission light detector can use a band-pass filter to instantly receive light rays with multiple wavelengths, or a plurality of transmission light detectors are arranged to detect the transmission light rays with different wavelengths by controlling the switch of the light source emitting the light rays with different wavelengths. The reflected light detector 6.2 is composed of a silicon photodiode, a photomultiplier tube, a multi-spectrometer with a light resolution function, etc., and is connected to one end of the composite optical fiber to detect a voltage value (mV) corresponding to the intensity of the reflected light of the particulate matter. The reflected light detector also has the function of a reference detector, can receive partial light rays emitted by the light source and detects the corresponding voltage value (mV). The reflected light detector 6.2 may use a band pass filter to instantly receive light of multiple wavelengths, or multiple reflected light detectors 6.2 may be provided to detect reflected light of different wavelengths by controlling the switching of LEDs with different wavelengths emitted from the light source.
Further, in one embodiment of the present invention, the transmitted light detection is detection of a voltage value corresponding to intensity of transmitted light of the particulate matter, and the reflected light detection is detection of a voltage value corresponding to intensity of reflected light of the particulate matter.
As shown in fig. 2, the measurement device according to the embodiment of the present invention includes, in addition to the above-described device:
the composite optical fiber 8: one end of the light source is connected with the reflected light detector, the other end is inserted in the container and is arranged opposite to the strip filter paper, and the light source is provided with a light transmitting part for transmitting the emitted light emitted by the light source to the strip filter paper, a reflected light receiving part for receiving the reflected light reflected by the granular substances on the strip filter paper, and a reflected light transmitting part for transmitting the reflected light. The composite optical fiber can realize the transmission of light by using E32-D32L 2M and the like produced by ohm dragon company.
The control device 9: the Processing Unit for controlling the operation of each part of the optical-method particulate matter measuring apparatus according to the present invention is realized by a microcomputer or a microprocessor including a Central Processing Unit (CPU), a read Only memory (rom), and a random Access memory (ram).
The storage device 10: the measurement device is constituted by a nonvolatile memory such as a flash memory or a Hard Disk Drive (HDD), and is used for storing a transmitted light attenuation coefficient and a reflected light attenuation coefficient (obtained by experiments described later), an Operating System (OS) program, a particulate matter measurement processing program, and various other application programs, and is executed by a control device.
The pumping pump 11: the pumping pump sets the pumping quantity at 1-20L/min through an electromagnetic valve according to the requirement. The suction pump sucks the atmosphere in the container through a suction pipeline, sucks the atmosphere into the air inlet rod from the air inlet, cuts the atmosphere through the cutting head, and collects the atmosphere by the strip-shaped filter paper after passing through the container.
A box body 12: used for installing and placing the devices.
Specifically, the measuring device of the embodiment of the present invention may be constituted by a band-shaped filter paper for collecting the atmosphere; a light source emitting light in a specific wavelength region; a light transmitting part connected with the light source and transmitting light to the strip-shaped filter paper; a reflection light receiving section above the band filter paper for receiving the light reflected by the particles on the band filter paper; a transmission light receiving part below the band-shaped filter paper and used for receiving the transmission light of the particles on the band-shaped filter paper; a reflected light detection unit for detecting the intensity of reflected light reflected by the particulate matter on the band-shaped filter paper; a transmitted light detecting section for detecting intensity of transmitted light transmitted through the particulate matter on the band-shaped filter paper; and a calculating part for calculating and collecting OC/EC contained in the particulate matter on the strip-shaped filter paper according to the light intensity detected by the reflected light detecting part and the transmitted light detecting part.
In order to make the operation principle of the measuring apparatus easier to understand, terms for measurement and the like of the present apparatus will be explained:
(1) the light of wavelength lambda generated by the light source emits the detected value of each detector.
a. Detection value (voltage value: mV) by transmission through photodetector: itrans (means, λ);
b. detection value (voltage value: mV) of the reflected light detector: ireflex (means, λ);
c. detection value (voltage value: mV) of the reflected light detector functioning as a reference detector: irefer (means, λ).
(2) The detected value of each detector under the state that the light source does not emit light.
a. Detection value (voltage value: mV) by transmission through photodetector: itrans (dark);
b. detection value (voltage value: mV) of the reflected light detector: ireflex (dark);
c. detected value (voltage value, mV) of the reflected light detector functioning as a reference detector: irefer (dark).
(3) Light intensity of transmitted light and reflected light of the blank band-shaped filter paper.
a. Transmitted light intensity: t (λ, 0);
b. intensity of reflected light: r (lambda, 0).
(4) And (4) after the strip-shaped filter paper collects the particles for t seconds, the light intensity of the transmitted light and the reflected light of the strip-shaped filter paper.
a. Transmitted light intensity: t (λ, T);
b. intensity of reflected light: r (lambda, t).
(5) And (3) acquiring the light intensity attenuation rate of the particles t seconds later by using the strip filter paper.
a. Attenuation rate of transmitted light intensity: tatn (λ, t);
b. attenuation rate of reflected light intensity: ratn (λ, t).
(6) Setting values of the strip-shaped filter paper support net.
a. Area of mesh in the band-shaped filter paper support net: asample;
b. area of linear material in the strip filter paper support net: asuport;
c. ratio of mesh in the band-shaped filter paper support net: α ═ Asupport/(Asample + Asupport).
(7) OC/EC and other component concentrations in the particulate material.
a. EC concentration calculated from the transmitted light intensity: [ EC ] t;
b. concentration of OC calculated from transmitted light intensity: [ OC ] t;
c. concentration of other components calculated from the transmitted light intensity: [ M ] t;
d. EC concentration calculated from the intensity of reflected light: [ EC ] r;
e. concentration of OC calculated from reflected light intensity: [ OC ] r;
f. concentration of other components calculated from the intensity of reflected light: [ M ] r.
(8) Attenuation coefficient of OC/EC and other components
Ec transmission light attenuation coefficient: ε [ EC, λ ];
transmission optical attenuation coefficient of oc: ε [ OC, λ ];
c. transmission light attenuation coefficient of other components: ε [ M, λ ];
reflection light attenuation coefficient of ec: σ [ EC, λ ];
reflected light attenuation coefficient of oc: σ [ OC, λ ];
f. reflection light attenuation coefficient of other components: σ [ M, λ ].
The following specific measurement method of the apparatus for measuring a granular material by an optical method according to the embodiment of the present invention is as follows:
(1) in the blank filter paper light intensity measurement, the filter paper pressing module is in a rising state by the control part, the reel is driven to rotate, the strip filter paper with fixed length is coiled, and then the filter paper pressing module is pressed. A light source, a composite optical fiber, a transmitted light detector, a reflected light detector and a processor are used to calculate the transmitted light intensity T (lambda, 0) of a blank strip filter paper according to the formula (1) in a calculation unit 1 and the reflected light intensity R (lambda, 0) according to the formula (2) in a calculation unit 2.
T(λ，0)＝[Itrans(means,λ)-Itrans(dark)]/[Irefer(means,λ)-Irefer(dark)]·······(1)
R(λ，0)＝[Ireflect(means,λ)-Ireflect(dark)]/[Irefer(means,λ)-Irefer(dark)]····(2)
(2) The transmitted light intensity T (λ, 0) and the reflected light intensity R (λ, 0) are acquired at a period of 1 second. The control device executes the following detection operations of the detectors within 300ms in a state that the light source is not emitting light: a transmission light detector Itrans (dark), a reflection light detector Ireflect (dark), a reflection light detector Irefer (dark) with reference to the function of the detector; the control device controls the light source to execute the following detection actions of the detector within 300ms under the condition of emitting light rays in the first wavelength region: a transmission photodetector Itrans (means, λ), a reflection photodetector Ireflect (means, λ), and a reflection photodetector Irefer (means, λ) functioning as a reference detector; the control device controls the light source to execute the following detection actions of the detector within 300ms under the condition of emitting light rays in the second wavelength region: a transmission photodetector Itrans (means, λ), a reflection photodetector Ireflect (means, λ), and a reflection photodetector Irefer (means, λ) functioning as a reference detector.
(3) And (6) collecting a sample. The control device starts the pumping pump to make the strip-shaped filter paper start to collect the granular substances in the atmosphere.
(4) After the belt-shaped filter paper collects the particulate matter for T seconds, the transmission intensity T (λ, T) and the reflection intensity R (λ, T) of the belt-shaped filter paper are measured. The control device controls the light source, the composite optical fiber, the transmitted light detector, the reflected light detector and the processor, the calculation part 1 calculates the transmitted light intensity T (lambda, T) of the strip-shaped filter paper after collecting the particulate matter for T seconds according to the formula (3), and the calculation part 2 calculates the reflected light intensity R (lambda, T) according to the formula (4).
T(λ，t)＝[Itrans(means,λ)-Itrans(dark)]/[Irefer(means,λ)-Irefer(dark)]·······(3)
R(λ，t)＝[Ireflect(means,λ)-Ireflect(dark)]/[Irefer(means,λ)-Irefer(dark)]····(4)
(5) The transmitted light intensity T (λ, T) and the reflected light intensity R (λ, T) are acquired at a period of 1 second. The control device executes the following detection operations of the detectors within 300ms in a state that the light source is not emitting light: a transmission light detector Itrans (dark), a reflection light detector Ireflect (dark), a reflection light detector Irefer (dark) with reference to the function of the detector; the control device controls the light source to execute the following detection actions of the detector within 300ms under the condition of emitting light rays in the first wavelength region: a transmission photodetector Itrans (means, λ), a reflection photodetector Ireflect (means, λ), and a reflection photodetector Irefer (means, λ) functioning as a reference detector; the control part controls the light source to execute the following detection actions of the detector within 300ms under the condition that the light source emits light rays in the second wavelength region: a transmission photodetector Itrans (means, λ), a reflection photodetector Ireflect (means, λ), and a reflection photodetector Irefer (means, λ) functioning as a reference detector.
(6) And calculating the attenuation rate Tatn (lambda, t) of the transmitted light intensity and the attenuation rate Ratn (lambda, t) of the reflected light intensity after the strip-shaped filter paper collects the particulate matters for t seconds. The data acquired according to the above-described procedure is calculated at the calculating section 1 by the formula (5) for Tatn (λ, t), and at the calculating section 2 by the formula (6) for Ratn (λ, t).
Tatn(λ，t)＝-Ln[T(λ,t)/T(λ,0)]················(5)
Ratn(λ，t)＝-Ln[{R(λ,t)-αR(λ,t)}/{R(λ,0)-αR(λ,0)}]······(6)
(7) The EC concentration [ EC ] t, the OC concentration [ OC ] t and the other component concentration [ M ] t are calculated in the calculation unit 1 based on the attenuation factor Tatn (λ, t) of the transmitted light intensity, and the EC concentration [ EC ] r, the OC concentration [ OC ] r and the other component concentration [ M ] r are calculated in the calculation unit 2 based on the attenuation factor Ratn (λ, t) of the reflected light intensity.
(8) Assuming that the light source alternately emits light of three wavelengths of λ 1, λ 2, λ 3, the calculation unit 1 calculates the EC concentration [ EC ] t, the OC concentration [ OC ] t, and the other component concentration [ M ] t according to the formulas (7), (8), (9) with reference to the transmission light attenuation coefficients of EC [ EC, λ 1], EC, λ 2, and ε [ EC, λ 3], the transmission light attenuation coefficients of OC [ OC, λ 1], ε [ OC, λ 2, and ε [ OC, λ 3], and the transmission light attenuation coefficients of OC [ M, λ 1], and ε [ M, λ 3], respectively.
Tatn(λ1)＝ε[OC,λ1]·[OC]t+ε[EC,λ1]·[EC]t+ε[M,λ1]·[M]t··················(7)
Tatn(λ2)＝ε[OC,λ2]·[OC]t+ε[EC,λ2]·[EC]t+ε[M,λ2]·[M]t··················(8)
Tatn(λ3)＝ε[OC,λ3]·[OC]t+ε[EC,λ3]·[EC]t+ε[M,λ3]·[M]t··················(9)
(9) With reference to the reflected light attenuation coefficients σ [ EC, λ 1], σ [ EC, λ 2], σ [ EC, λ 3] of EC, the reflected light attenuation coefficients σ [ OC, λ 1], σ [ OC, λ 2], σ [ OC, λ 3] of OC, the reflected light attenuation coefficients σ [ M, λ 1], σ [ M, λ 2], σ [ M, λ 3] of other components, the concentration [ EC ] r of EC, the concentration [ OC ] r of OC, and the concentration [ M ] r of other components are calculated in the calculation section 2 according to the formulas (10), (11), (12).
Ratn(λ1)＝σ[OC,λ1]·[OC]r+σ[EC,λ1]·[EC]r+σ[M,λ1]·[M]r·················(10)
Ratn(λ2)＝σ[OC,λ2]·[OC]r+σ[EC,λ2]·[EC]r+σ[M,λ2]·[M]r·················(11)
Ratn(λ3)＝σ[OC,λ3]·[OC]r+σ[EC,λ3]·[EC]r+σ[M,λ3]·[M]r·················(12)
In addition, when two components M1 and M2 other than OC/EC are present in the particulate matter, the concentrations thereof can be calculated from the equations (7), (8), (10), and (11).
The measurement of the OC/EC concentration in the apparatus for measuring a particulate matter by an optical method according to the present invention will be described in detail with reference to the following examples.
Assuming that only two components OC/EC are present in the particulate matter, the light source emits light with wavelengths λ 375nm and λ 890 nm.
In this case, as shown in FIG. 4, the transmission light intensity attenuation rates Tatn (λ 375nm) and Tatn (λ 890nm) are actually measured. As shown in FIG. 5, the measured data of the reflected light intensity attenuation rates Ratn (. lamda.375 nm) and Ratn (. lamda.890 nm) are shown.
The calculation unit 1 calculates the EC concentration [ EC ] t and the OC concentration [ OC ] t according to the equations (13) and (14).
Tatn(λ375nm)＝ε[OC,λ375nm]·[OC]t+ε[EC,λ375nm]·[EC]t···············(13)
Tatn(λ890nm)＝ε[OC,λ890nm]·[OC]t+ε[EC,λ890nm]·[EC]t················(14)
The calculation unit 2 calculates the EC concentration [ EC ] r and the OC concentration [ OC ] r according to the equations (15) and (16).
Ratn(λ375nm)＝σ[OC,λ375nm]·[OC]r+σ[EC,λ375nm]·[EC]r················(15)
Ratn(λ890nm)＝σ[OC,λ890nm]·[OC]r+σ[EC,λ890nm]·[EC]r················(16)
Then, it was experimentally found that the transmitted light attenuation coefficient ∈ [ EC, λ 375nm ] of EC was "0.30", ∈ [ EC, λ 890nm ] was "0.30", the transmitted light attenuation coefficient ∈ [ OC, λ 375nm ] of OC was "0.10", the ∈ [ OC, λ 890nm ] was "0", the reflected light attenuation coefficient σ [ EC, λ 375nm ] of EC was "0.32", the σ [ EC, λ 890nm ] was "0.20", the reflected light attenuation coefficient σ [ OC, λ 375nm ] of OC was "0.20", and the σ [ OC, λ 890nm ] was "0".
As shown in FIGS. 6-8, the calculation results of OC/EC concentrations.
As shown in fig. 9, it is understood that the measurement results of the optical-method particulate matter measuring apparatus have a good correlation between the measurement results of the transmitted light intensity and the reflected light intensity and wsoc.
As shown in FIG. 10, OC concentration [ OC ] measured by the apparatus for measuring a granular material by an optical method according to the embodiment of the present invention]t(μgC/m3) Analysis with carbonOC concentration in PM2.5 (μ gC/m) measured by the Instrument3) The correlation of (c). The carbon analyzer is provided with a thermal decomposition tube and CO2Analyzer, which determines the concentration by decomposing the organic carbon in PM 2.5.
As shown in fig. 10, the calculation method is: using the above formula (13), (14) in the epsilon [ OC, lambda 375nm]-ε[OC,λ890nm]＝1/17.5，ε[EC,λ375nm]-ε[EC,λ890nm]When the concentration is 0, OC concentration [ OC ] is calculated according to formula (17)]t(μgC/m3)。
[OC]t＝17.5[Tatn(λ375nm)-Tatn(λ890nm)]···········(17)
As shown in fig. 10, it can be seen that OC concentration [ OC ] t measured by the optical-method particulate matter measuring device has a good correlation with OC concentration measured by the carbon analyzer.
As shown in FIG. 11, the EC concentration [ EC ] calculated from the intensity of the reflected light measured by the optical-method particulate matter measuring apparatus according to the example of the present invention]r(μgC/m3) EC concentration in PM2.5 (μ gC/m) determined by carbon analyzer3) The correlation of (c). The carbon analyzer is provided with a thermal decomposition tube and CO2Analyzer, determining the concentration by decomposing the elemental carbon in PM 2.5.
As shown in FIG. 11, the EC concentration [ EC ] measured by the optical-method particulate matter measuring apparatus]r result, the calculation method is: using the above formula (16), σ [ EC, λ 890nm]>>σ[OC,λ890nm]，σ[EC,λ890nm]EC concentration [ EC ] was calculated according to formula (18) as 1/4.99]r(μgC/m3)。
Ratn(λ890nm)＝σ[EC,λ890nm]·[EC]r···············(18)
As shown in fig. 11, it is understood that the EC concentration [ EC ] r measured by the optical-method particulate matter measuring apparatus has a good correlation with the EC concentration measured by the carbon analyzer.
The above embodiments show that the embodiments of the present invention are different from the prior art, and the embodiments of the present invention do not perform thermal decomposition on the collected sample, do not need to perform pretreatment, do not damage the sample, and make the measurement more accurate. The determination device of the invention does not need carrier gas, reduces the operation cost, is simpler and more convenient, can determine the concentration of OC/EC contained in atmospheric particulates by using an optical method under the conditions of no need of sample pretreatment and carrier gas carrying, and has accurate determination, low cost and simple maintenance. In addition, the measuring apparatus of the embodiment of the present invention stores program information and the like from the storage device; the control device executes the program information in the memory part to control the operation of the instrument; effectively collecting a sample by using Teflon strip-shaped filter paper; directly measuring the collected sample by an optical method to obtain a light intensity value; and calculating the measured light intensity result by a processor so as to calculate the content concentration of OC/EC in the collected sample particles.
In summary, the measurement apparatus according to the embodiment of the present invention has the following key features.
(1) The band-shaped filter paper is used for collecting granular substances in the atmosphere; a light source emitting light in a specific first wavelength region (220nm-500nm) and a specific second wavelength region (650nm-1000 nm); a light transmitting part connected with the light source and transmitting the light emitted by the light source to the strip-shaped filter paper above the strip-shaped filter paper; a transmitted light receiving part for receiving the transmitted light intensity of the collected granular substances and a transmitted light detecting part for detecting the light intensity under the strip-shaped filter paper; and a processor connected to the transmitted light detector for calculating the concentration of organic carbon contained in the collected particles based on the intensity of light detected by the transmitted light detector.
(2) The band-shaped filter paper is used for collecting granular substances in the atmosphere; a light source having a first wavelength region and a second wavelength region which emit light in a specific range; a light transmitting part connected with the light source and transmitting the light emitted by the light source to the strip-shaped filter paper above the strip-shaped filter paper; a reflection light receiving section for receiving light reflected by the particulate matter collected by the strip filter paper and a reflected light detecting section for detecting the intensity of the light above the strip filter paper; and a processor connected to the reflected light detection unit and calculating the concentration of organic carbon contained in the collected particulate matter based on the intensity of light detected by the reflected light detection unit.
(3) The band-shaped filter paper is used for collecting granular substances in the atmosphere; a light source having a first wavelength region and a second wavelength region which emit light in a specific range; a light transmitting part connected with the light source and transmitting the light emitted by the light source to the strip-shaped filter paper above the strip-shaped filter paper; a transmitted light receiving part for receiving the transmitted light intensity of the collected granular substances and a transmitted light detecting part for detecting the light intensity under the strip-shaped filter paper; a reflection light receiving section for receiving light reflected by the particulate matter collected by the strip filter paper and a reflected light detecting section for detecting the intensity of the light above the strip filter paper; and a processor connected to the transmitted light detection unit and the reflected light detection unit, for calculating the concentration of organic carbon contained in the collected particulate matter based on the intensity of light detected by the transmitted light detection unit and the reflected light detection unit.
According to the optical method granular substance measuring device provided by the embodiment of the invention, thermal decomposition and pretreatment of the collected sample are not needed, the sample is not damaged, and the measurement is more accurate; the measuring device does not need carrier gas, so that the running cost is reduced, and the device is simpler and more convenient; and the OC/EC concentration contained in the atmospheric particulates can be measured by an optical method under the conditions of no need of sample pretreatment and no need of carrying carrier gas, and the method has the advantages of accurate measurement, low cost and simple maintenance.
Next, a description is given of an optical method particulate matter measuring method according to an embodiment of the present invention with reference to the drawings.
Fig. 12 is a flowchart of a method for measuring a particulate matter by an optical method according to an embodiment of the present invention.
As shown in fig. 12, the optical method for measuring a particulate matter includes the steps of:
in step S101, the atmosphere is collected and cut into particles of a predetermined particle size range.
In step S102, the particles cut to the predetermined particle size range are respectively entered into the left container and the right container through the container forming gas passage to perform band filter paper trapping.
Further, in an embodiment of the present invention, the filtering of the particles cut into the predetermined size range into the left container and the right container, respectively, further comprises: when the particle size of the cut particles is smaller than the preset particle size, the particles enter a left container; when the particle size of the cut particles is larger than the preset particle size, the particles enter the right container.
In step S103, the light source alternately emits light in a specific wavelength region to the band-shaped filter paper, the detector receives the light in the specific wavelength region, detects reflected light and transmitted light by the light in the specific wavelength region to obtain voltage values of the reflected light and the transmitted light, and calculates the OC/EC concentration in the particles captured on the band-shaped filter paper.
Further, in an embodiment of the present invention, the detecting of the reflected light and the transmitted light by the light in the specific wavelength region further includes: detecting, with a transmitted light detector, transmitted light of a plurality of wavelengths received by the band-pass filter; a reflected light detector is used to detect reflected light in the plurality of wavelengths received by the band pass filter.
Further, in one embodiment of the present invention, the transmitted light detection is detection of a voltage value corresponding to intensity of transmitted light of the particulate matter, and the reflected light detection is detection of a voltage value corresponding to intensity of reflected light of the particulate matter.
It should be noted that the above explanation of the embodiment of the apparatus for measuring a particulate matter by an optical method is also applicable to the method, and will not be described herein again.
According to the method for determining the granular substances by the optical method, provided by the embodiment of the invention, the collected samples do not need to be subjected to thermal decomposition and pretreatment, the samples are not damaged, and the determination is more accurate; the measuring device does not need carrier gas, so that the running cost is reduced, and the device is simpler and more convenient; and the OC/EC concentration contained in the atmospheric particulates can be measured by an optical method under the conditions of no need of sample pretreatment and no need of carrying carrier gas, and the method has the advantages of accurate measurement, low cost and simple maintenance.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. An optical-method particulate matter measuring apparatus, comprising:
the collecting device is used for collecting the atmosphere;
the cutting head is used for cutting the atmosphere into particles with a preset particle size range;
a container for forming a gas passage for allowing the particles cut into a predetermined particle size range to enter the left container and the right container, respectively;
a trapping device for trapping the plurality of particles in the container by using a band-shaped filter paper;
a light source for alternately emitting light in a specific wavelength region to the band-shaped filter paper;
the detection device is used for receiving the light rays with different wavelengths emitted by the light source and detecting the reflected light and the transmitted light with different wavelengths through the detector; and
a processor for calculating the concentration of OC/EC in the particles captured on the strip-shaped filter paper by the voltage value detected by the detector;
wherein, the EC concentration [ EC ] t, the OC concentration [ OC ] t and the other component concentration [ M ] t are calculated from the attenuation rate Tatn (lambda, t) of the transmitted light intensity, and the EC concentration [ EC ] r, the OC concentration [ OC ] r and the other component concentration [ M ] r are calculated from the attenuation rate Ratn (lambda, t) of the reflected light intensity;
if the light source alternately emits light with three wavelengths of lambda 1, lambda 2 and lambda 3, the concentration [ EC ] t of EC, the concentration [ OC ] t of OC and the concentration [ M ] t of other components are calculated:
Tatn(λ1)＝ε[OC,λ1]·[OC]t+ε[EC,λ1]·[EC]t+ε[M,λ1]·[M]t
Tatn(λ2)＝ε[OC,λ2]·[OC]t+ε[EC,λ2]·[EC]t+ε[M,λ2]·[M]t
Tatn(λ3)＝ε[OC,λ3]·[OC]t+ε[EC,λ3]·[EC]t+ε[M,λ3]·[M]t
wherein ε [ EC, λ 1], ε [ EC, λ 2], ε [ EC, λ 3] represent the transmission light attenuation coefficients of EC, ε [ OC, λ 1], ε [ OC, λ 2], ε [ OC, λ 3] represent the transmission light attenuation coefficients of OC, and ε [ M, λ 1], ε [ M, λ 2], ε [ M, λ 3] represent the transmission light attenuation coefficients of other components;
calculating the concentration of EC [ EC ] r, OC [ OC ] r and other components [ M ] r:
Ratn(λ1)＝σ[OC,λ1]·[OC]r+σ[EC,λ1]·[EC]r+σ[M,λ1]·[M]r
Ratn(λ2)＝σ[OC,λ2]·[OC]r+σ[EC,λ2]·[EC]r+σ[M,λ2]·[M]r
Ratn(λ3)＝σ[OC,λ3]·[OC]r+σ[EC,λ3]·[EC]r+σ[M,λ3]·[M]r
wherein σ [ EC, λ 1], σ [ EC, λ 2], σ [ EC, λ 3] denote the reflection light attenuation coefficient of EC, σ [ OC, λ 1], σ [ OC, λ 2], σ [ OC, λ 3] denote the reflection light attenuation coefficient of OC, and σ [ M, λ 1], σ [ M, λ 2], σ [ M, λ 3] denote the reflection light attenuation coefficients of other components.
2. The apparatus for measuring granular substances by an optical method according to claim 1, wherein the collecting means comprises: the air inlet rod is connected with the air inlet and the cutting head to form a sampling atmosphere channel.
3. The optical-method particulate matter measuring apparatus according to claim 1, wherein the trap device includes:
the banded filter paper is used for trapping the particles cut into the preset particle size range;
a rewinding shaft for mounting the band-shaped filter paper;
a reel for winding the band-shaped filter paper of a fixed length;
and the filter paper breakage inductor is used for detecting whether the strip filter paper is broken by utilizing an optical principle so as to judge whether the instrument normally operates for measurement.
4. The optical-method particulate matter measuring apparatus according to claim 1, wherein the container includes:
the gas pumping pipeline is used for connecting the container and the pumping pump to form a gas channel;
the pressure sensor is used for detecting a pressure value so as to ensure the normal operation and measurement of the device;
the filter is used for filtering dust possibly existing in the suction pipeline so as to ensure that the device components work normally;
the flow sensor is used for sensing the flow of the gas channel to carry out real-time monitoring;
and the electromagnetic valve is used for flow control.
5. The optical-method particulate matter measuring apparatus according to claim 1, wherein the detecting device includes a transmitted light detector for detecting transmitted light of the plurality of wavelengths received by the band pass filter and a reflected light detector for detecting reflected light of the plurality of wavelengths received by the band pass filter.
6. The apparatus for measuring a granular substance by an optical method according to claim 5, wherein the detection of transmitted light is detection of a voltage value corresponding to an intensity of transmitted light of the granular substance, and the detection of reflected light is detection of a voltage value corresponding to an intensity of reflected light of the granular substance.
7. An optical method for measuring granular substances is characterized by comprising the following steps:
collecting atmosphere, and cutting the atmosphere into particles with a preset particle size range;
forming a gas channel through the container to enable the particles cut into the preset particle size range to respectively enter the left container and the right container so as to carry out banded filter paper trapping; and
the light source alternately emits light rays in a specific wavelength region to the strip-shaped filter paper, the detector receives the light rays in the specific wavelength region, detects reflected light rays and transmitted light rays through the light rays in the specific wavelength region to obtain voltage values of the reflected light rays and the transmitted light rays, and calculates the concentration of OC/EC in particles captured on the strip-shaped filter paper;
wherein, the EC concentration [ EC ] t, the OC concentration [ OC ] t and the other component concentration [ M ] t are calculated from the attenuation rate Tatn (lambda, t) of the transmitted light intensity, and the EC concentration [ EC ] r, the OC concentration [ OC ] r and the other component concentration [ M ] r are calculated from the attenuation rate Ratn (lambda, t) of the reflected light intensity;
if the light source alternately emits light with three wavelengths of lambda 1, lambda 2 and lambda 3, the concentration [ EC ] t of EC, the concentration [ OC ] t of OC and the concentration [ M ] t of other components are calculated:
Tatn(λ1)＝ε[OC,λ1]·[OC]t+ε[EC,λ1]·[EC]t+ε[M,λ1]·[M]t
Tatn(λ2)＝ε[OC,λ2]·[OC]t+ε[EC,λ2]·[EC]t+ε[M,λ2]·[M]t
Tatn(λ3)＝ε[OC,λ3]·[OC]t+ε[EC,λ3]·[EC]t+ε[M,λ3]·[M]t
wherein ε [ EC, λ 1], ε [ EC, λ 2], ε [ EC, λ 3] represent the transmission light attenuation coefficients of EC, ε [ OC, λ 1], ε [ OC, λ 2], ε [ OC, λ 3] represent the transmission light attenuation coefficients of OC, and ε [ M, λ 1], ε [ M, λ 2], ε [ M, λ 3] represent the transmission light attenuation coefficients of other components;
calculating the concentration of EC [ EC ] r, OC [ OC ] r and other components [ M ] r:
Ratn(λ1)＝σ[OC,λ1]·[OC]r+σ[EC,λ1]·[EC]r+σ[M,λ1]·[M]r
Ratn(λ2)＝σ[OC,λ2]·[OC]r+σ[EC,λ2]·[EC]r+σ[M,λ2]·[M]r
Ratn(λ3)＝σ[OC,λ3]·[OC]r+σ[EC,λ3]·[EC]r+σ[M,λ3]·[M]r
wherein σ [ EC, λ 1], σ [ EC, λ 2], σ [ EC, λ 3] denote the reflection light attenuation coefficient of EC, σ [ OC, λ 1], σ [ OC, λ 2], σ [ OC, λ 3] denote the reflection light attenuation coefficient of OC, and σ [ M, λ 1], σ [ M, λ 2], σ [ M, λ 3] denote the reflection light attenuation coefficients of other components.
8. The method for optically measuring granular substances according to claim 7, wherein the step of filtering the particles cut to have a predetermined size range into the left container and the right container, respectively, further comprises:
when the particle size of the cut particles is smaller than the preset particle size, the particles enter a left container;
and when the particle size of the cut particles is larger than the preset particle size, the particles enter the right container.
9. The method for optically measuring a particulate matter according to claim 7, wherein the detection of the reflected light and the transmitted light by the light in the specific wavelength region further comprises:
detecting, with a transmitted light detector, transmitted light of a plurality of wavelengths received by the band-pass filter;
a reflected light detector is used to detect reflected light in the plurality of wavelengths received by the band pass filter.
10. The method for optically measuring a particulate matter as claimed in claim 9, wherein the detection of the transmitted light is detection of a voltage value corresponding to an intensity of the transmitted light of the particulate matter, and the detection of the reflected light is detection of a voltage value corresponding to an intensity of the reflected light of the particulate matter.
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