Design And Research Of Light Scattering Particle Counting Sensor

With the advancement of modern science and technology,the requirements for the accuracy and reliability of measurement of the cleanliness of different working media in many fields are constantly increasing.Now Measurement techniques of particle contamination to liquid medium,especially to oil medium vary from different to different.At present extensive measurements are widely used,such as settlement method,light diffraction method,electric induction method,light blockage method,light scattering method,ect.A variety of particle measurement techniques are improving and evolving.Light scattering method combines laser technology,photoelectric conversion technology,electronic circuit technology and computer programming technology.Light scattering method has become the most promising and development prospects of particle detection technology,for the virtue of detection speed,particle size measurement range,reliability,high intelligence and so on.The paper is based on the light scattering theory to design and improves the traditional light scattering particle counting sensors,which is divided into the following three parts:1.Based on Mie scattering theory,the relationship between refractive index,extinction coefficients and scale parameters of different materials in hydraulic oil was discussed by means of Matlab software programming,and the characteristics of Mie scattering are analyzed.The two types of scattered light collections,which are near-forward scattered light collection structure and right-angle directional scattered light collection structure,are compared,and compared with a polarized light and a natural light as an incident light respectively,calculated under the same light intensity of the light scattering particle counting sensor two commonly used scattered light collecting structure of the light quantity.2.The light scattering particle counter circuit design and the circuit noise calculation are introduced,and the design of software part of light scattering particle counter is described,including the overall design of oil on-line system and the design method of particle counting module.By mapping the size of the particles in the oil by means of an optical microscope and measuring the voltage values output from the standard spherical particles in the calibration solution purchased,the corresponding relationship between the particle size and the output voltage is fitted,at the same time introduced in PCB circuit board design to prevent electromagnetic interference.By using Arduino development board design platform,the experimentally measured relationship between particle size and output voltage is programmed to not only realize the on-line detection of particles contaminated with oil in the hydraulic system,but also achieve recording and storage functions,the monitoring data uploaded to the switchboard in a timely manner,and the latter part of the processing and analysis provides a reliable data and information resources.3.The working principle of the light scattering particle counter is introduced,and the different forms of scattering light collecting structure are compared,and introduced for the design of the oil passage part of the particle counter and the calculation of the main parameters of the particle counter.Through the improvements to the oil passage part,the rotating blades are added to rotate the oil particles to make the particles rotate,the particle size can be measured more accurately,and the error caused by the unilateral light measurement can be reduced and avoided.In addition,by analyzing the flow field of the oil at the cross section of different oil passages and the simulation of FLUENT,the pressure and velocity of the flow field at different cross sections are calculated,and the movement patterns of the particles in the oil passage after the particles are added and simulated.