Key Technologys Of The Dust On-line Monitoring Instrument Based On The Principle Of Laser Scattering

Atmospheric particulate pollution has become an important factor of environmental pollution,therefore,local governments and environmental protection departments continuously invested a large amount of manpower,materials and capital to control and prevent particulate pollution,and put forward an idea of grid management.Aiming at the high price challenges of environmental monitoring equipment,this paper proposed to develop a miniaturized,low-cost,high real-time atmospheric particulate measuring instrument based on laser scattering,and design a monitoring system for atmospheric particulate matter concentration based on angular scattering.Meanwhile it has also studied the mathematical model and calibration method of the dust sensor.The main contents are as followings.(1)Designing the dust sensor based on angular scattering.According to Mie scattering theory,the technical scheme of angular scattering structure is used to finish the dust system design through analyzing the principle,application occasions,advantages and disadvantages of light scattering dust sensor,which includes the design and implementation of lighting structure,signal processing,calculation,flow control and detection.(2)Completing the mathematical model and calibration method design of the dust sensor.Analyzing the influence of wavelength,refractive index and scattering angle on the intensity of scattering light,and determining the lighting mode and lighting angle;analyzing the effect of particle size on scattered light,and combining lighting mode to get the relationship between luminous flux F and particle diameter D;then proposing the data processing and calculating method of the dust sensor through the F~D curve and lighting structure,and the calibration requirement based on the application situation and the mathematical model of the dust sensor,then designing the calibration equipment and calibration software,so as to complete the zero calibration,particle size calibration and consistency calibration of the dust sensor.(3)Through the outdoor experiment and data evaluation of the dust sensor,it is proved that the dust sensor is feasible to serve as the particulate matter monitoring instrument in the grid engineering of environmental pollution.Setting up the experimental data service platform,completing the online real-time measurement of PM10 concentration in outdoor scene,and evaluating the sensor from two aspects of accuracy and consistency.In terms of accuracy,when the concentration of PM10 is 0-70 ?g/m3,the maximum measurement error is 7?g/m3,and the obtained relative error is 10%;when the concentration of PM10 is 225 ?g/m3,the maximum error is-33 ?g/m3,then the relative error is 14.67%;in terms of consistency,the Pearson relevance between each two sets among the five equipment is 0.970,which is relatively high.Then from the existing experimental data,the performance of the sensor can meet the design requirements,thus it can be used in the grid engineering of atmospheric particulate monitoring that has been mentioned above.