Research Dust Concentration Detection Based On Finel Lens

In recent years, with the rapid development of agriculture and science technology, many industries have been developing rapidly in China, which provided a convenient and comfortable environment while also produced a large amount of pollutants. Due to the increased number of dust particles in the atmosphere, people’s health and daily life was some kind of threat.It is a very important for environmental protection and control that Measuring the concentration of dust in the atmosphere.The common measurement method for dust concentration is contact measuring method, which can achieve higher accuracy, but it needs long testing period and the high cost, which have a number of advantages, and get more attention and were used widely.Aim at the problem for poor accuracy of transmission method and scattering method takes advantages of optical methods, the method was proposed to measuring the concentration of dust, which combination of scattering method and transmission method and based on Fresnel lens.When light through the dust zone which will be measured, the part of light energy is absorbed, its mode of transmission is not changed;another part of light energy is scattering, the propagation path was changed. Based on the principle of scattering method and transmission method,the concentration of dust can be reflected indirectly, by measuring the degree of attenuation of the transmitted light or scattered light.Its range is limited, which only using light transmission method or light scattering method to detect dust concentration. When the dust concentration gets higher or lower, this way does not measure the concentration of dust accurately.In order to further improve the measuring method of the dust concentration in the air, the concentration of dust was measured by combined with light scattering and light transmission method. By using Fresnel lenses, to diffuse the point light sources as the large-area parallel light. According to measuring the intensity of light through the dust area. Based on the Lamber principleand the Mie scattering law, by selecting a specific scattering angle, the detected scattering signal and transmission signal are transferred to the computer,by signal acquisition system, for data processing.The experimental results show that the proposed method increases the area of the test area, and increases the measurement accuracy. This method of measurement is accurate and reliable for high dust concentration or low dust concentration.