Particle concentration based on mie scattering theory monitoring system and using method thereofTechnical field
The present invention relates to airborne dust technical field of measurement of particulate matter concentration, be specifically related to a kind of particle concentration based on mie scattering theory monitoring system and using method thereof.
Background technology
Atmospheric Grains source complexity, result of study shows, airborne dust is one of key factor causing Atmospheric Particulate Matter, its source predominantly road, construction site, pier storage yard etc..Airborne dust particle size range is big, concentration change is quick, therefore the change of monitoring airborne dust need applied widely, measuring speed fast, can the method for On-line sampling system.
The method of currently used monitoring particle concentration is mainly traditional β ray method and concussion sedimentation balance method, on the one hand both approaches needs sampling, certainty of measurement is easily subject to sampling apparatus impact, on the other hand cannot effectively distinguish different diameter airborne particle, therefore cannot realize on-line measurement.
When the principle of light scattering refers to the particulate matter that light is irradiated in medium, can deviate the direction of propagation with medium interaction, scattering causes the decay of light in all directions.Light scattering situation in all directions depends on the parameters such as the refractive index of the wavelength of light, the particle diameter of particulate matter and particulate matter.The product of the outer existing light scattering measurement particle concentration of Current Domestic is all extraction-type light scattering measurement equipment.The sampler extraction of the equipment configuration air containing particulate matter, isolates certain particle diameter particles below thing by particle sickle, and these particulate matters enter light scattering measurement space along with air-flow, record the scattered light intensity under special angle, calculate particle concentration.The accuracy of instrument depends on particle sickle and sampler, the accuracy of particle cutting and the discharge stability of sampler and measurement result causes the biggest impact.
Summary of the invention
For solving the problems referred to above, the invention provides a kind of particle concentration based on mie scattering theory monitoring system and using method thereof, have noncontact, on a large scale, measure in real time, accurately and reliably, advantage easy to use.
For achieving the above object, the technical scheme that the present invention takes is:
Particle concentration based on mie scattering theory monitoring system, including transmitting terminal, receiving terminal, Single Chip Microcomputer (SCM) system and 3G communication module, described transmitting terminal is by laser instrument, Laser Driven module, the first signal processing circuit module composition, use the laser instrument of four kinds of different wave lengths, all it is furnished with PD outfan feedback laser shoot laser light intensity, the error brought in order to correct output intensity change；The front of laser instrument is provided with beam expanding lens, makes incident laser hot spot bigger and ensures the depth of parallelism；First signal processing circuit, for providing modulated signal to laser instrument, is acquired PD output end signal and uploads to Single Chip Microcomputer (SCM) system；Described receiving terminal is processed circuit by light intensity receiving unit, secondary signal and forms, and light intensity receiving unit uses silicon cell as photo-electric conversion element, the light path system closed with condenser lens, filter plate composition；Advantageously reduce ambient light disturb and improve signal to noise ratio；Secondary signal processes circuit, the process that signal for receiving photo-electric conversion element filters and demodulates, gather signal and be sent to Single Chip Microcomputer (SCM) system, Single Chip Microcomputer (SCM) system, for airborne dust concentration information is sent to remote platform from measure field by 3G communication module by data, it is achieved the far-end measuring of airborne dust particle concentration.
For solving the problems referred to above, present invention also offers the using method of above-mentioned particle concentration based on mie scattering theory monitoring system, comprise the steps:
S1, system is placed in clean room, measures one group of light intensity value Itest, by light intensity value I nowtestAs system incident intensity I in airborne dust space0；
S2, system being placed in airborne dust space, transmitting terminal launches four tunnels modulation laser signals, occurs light scattering to decay by airborne dust space, and the light intensity after decay is received by receiving terminal and obtains transmitted light intensity I；
S3, the blue ripple Beer law of utilization combine light path and calculate the turbidity value under the wavelength of each road；
S4, use function limit solution thought, initially set up airborne dust particle size distributed model in space；Then the turbidity value under the wavelength of each road is combined according to Mie scattering law, by the practical situation of optimized algorithm inverting particle size distribution；Finally combine the particle concentration distributed model that inverting obtains, obtained the numerical value of PM2.5, PM10 and TSP by integration；
S5, the value of calculation of airborne dust particle concentration is sent to remote platform by 3G communication module.
The method have the advantages that
1, the present invention penetrates incident beam by No. four laser instrument in side, airborne dust space, and incident beam is detected by dusty space receiving end, and follow-up calculating is all based on the light intensity measured, and therefore system can monitor the particle concentration change in airborne dust space in real time.
2, the present invention uses the measuring method of open path, it is not necessary to sampler and particle sickle, and the particle concentration not changing measurement space in dust environment is distributed, and reduces the intermediate link of measurement, adds certainty of measurement.
3, the system structure of the present invention can realize large-range measuring by adjusting light path, it is possible to the airborne dust concentration of detection airborne dust space diverse location as required.
4, present invention achieves simply, easy to use, reliability is high, can monitor by far-end, can be long lasting for for airborne dust space measuring concentration of granules in certain.
Accompanying drawing explanation
Fig. 1 is the structure chart of a light path in embodiment of the present invention particle concentration based on mie scattering theory monitoring system.
Detailed description of the invention
In order to make objects and advantages of the present invention clearer, below in conjunction with embodiment, the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.
As shown in Figure 1, embodiments provide a kind of particle concentration based on mie scattering theory monitoring system, including transmitting terminal, receiving terminal, Single Chip Microcomputer (SCM) system and 3G communication module, described transmitting terminal is by laser instrument, Laser Driven module, the first signal processing circuit module composition, use the laser instrument of four kinds of different wave lengths, all it is furnished with PD outfan feedback laser shoot laser light intensity, the error brought in order to correct output intensity change；The front of laser instrument is provided with beam expanding lens, makes incident laser hot spot bigger and ensures the depth of parallelism；First signal processing circuit, for providing modulated signal to laser instrument, is acquired PD output end signal and uploads to Single Chip Microcomputer (SCM) system；Described receiving terminal is processed circuit by light intensity receiving unit, secondary signal and forms, and light intensity receiving unit uses silicon cell as photo-electric conversion element, the light path system closed with condenser lens, filter plate composition；Advantageously reduce ambient light disturb and improve signal to noise ratio；Secondary signal processes circuit, the process that signal for receiving photo-electric conversion element filters and demodulates, gather signal and be sent to Single Chip Microcomputer (SCM) system, Single Chip Microcomputer (SCM) system, for airborne dust concentration information is sent to remote platform from measure field by 3G communication module by data, it is achieved the far-end measuring of airborne dust particle concentration.
Wherein, laser instrument and receiving unit one have four tunnels, only provide one of them light channel structure figure in Fig. 1, and other three tunnels are identical except laser device laser wavelength external structure different from optical filter wave band.
The embodiment of the present invention additionally provides the using method of above-mentioned particle concentration based on mie scattering theory monitoring system, comprises the steps:
S1, system is placed in clean room, measures one group of light intensity value Itest, by light intensity value I nowtestAs system incident intensity I in airborne dust space0；
S2, system being placed in airborne dust space, transmitting terminal launches four tunnels modulation laser signals, occurs light scattering to decay by airborne dust space, and the light intensity after decay is received by receiving terminal and obtains transmitted light intensity I；
S3, the blue ripple Beer law of utilization combine light path and calculate the turbidity value under the wavelength of each road；
S4, use function limit solution thought, initially set up airborne dust particle size distributed model in space；Then the turbidity value under the wavelength of each road is combined according to Mie scattering law, by the practical situation of optimized algorithm inverting particle size distribution；Finally combine the particle concentration distributed model that inverting obtains, obtained the numerical value of PM2.5, PM10 and TSP by integration；
S5, the value of calculation of airborne dust particle concentration is sent to remote platform by 3G communication module.
Originally being embodied as system transmitting terminal laser instrument and launch the parallel incident laser beam of four road different wave lengths, laser beam is scattered by particulate matter by airborne dust space, and the transmission laser after decay is received by silicon cell, can obtain transmission laser light intensity.For ensureing the accuracy of receiving terminal data, reducing ambient light interference, incident illumination exports through square-wave frequency modulation, obtains light intensity value by the transmission light in airborne dust space is demodulated.
The above is only the preferred embodiment of the present invention; it should be pointed out that, for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be regarded as protection scope of the present invention.