Design And Research Of Monodisperse High Concentration Laser Dust Particle Counter

As an effective air cleanliness monitoring device,the dust particle counter plays an increasingly important role in people's lives and production processes in modern society.Studying a high-concentration dust particle counter has a very significant effect on detecting emission indexes of high-concentration particles such as automobile exhaust and industrial exhaust gas.In order to improve the concentration of the monodisperse particle counting sensor,the working principle of the traditional dust particle counter is analyzed.Based on the research of the traditional dust particle counter at home and abroad,the corresponding transformation and innovation are carried out.Through the study of the structure of the photosensitive region,the beam is shaped by an aspherical lens plus a cylindrical mirror structure,so that the photosensitive region is narrower than the conventional particle counter,which improves the counting efficiency;The use of a dual detector structure replaces the traditional detector module,so that particles in different spaces are counted by different detectors,greatly reducing the probability of false detection and missed detection of particles;The use of a transimpedance input design with bootstrap function improves the frequency characteristics of the system and reduces the frequency.The input noise makes it possible to perform the small signal amplification function well,and the second-order KRC and the nonlinear processing circuit are combined in the subsequent circuit module to improve the measurement range.On this basis,the new laser dust particle counter was tested and analyzed,and the particle size files were calibrated.The results showed that the particle size distribution errors of 0.4?m particles and 0.6?m particles were 4.85%and 10.23%,respectively.It meets the“JJF 1190-2008 Calibration Specification for Airborne Particle Counter”standard.Compared with the traditional particle counter,the highest measurement concentration reaches the order of 10~9/m~3,which meets the design requirements.