Research On Key Technologies Of Pollution Particle Size Sensor Based On Light Blockage Principle

As the manufacturing industry develops,the use of oil equipment is gradually increasing,which brings countless equipment failure problems caused by oil particles.Studies have found that different particle sizes cause different types of equipment damage,so research and development of particle size measurement instruments are essential for the regular replacement and maintenance of oil equipment.As the core component of the measurement instrument,the measurement accuracy and application form of the particle size sensor are extremely important.Therefore,researching a high-precision and low-cost particle size sensor is of great significance.The main research content of this article is as follows:Firstly,based on the detection principle of the photoresist method,the optical path structure and the optical path housing design of the particle size sensor were designed.In the optical path design,the wavelength of the light source was determined based on the different absorption degrees of oil at different wavelengths.The collimation design and software simulation of the light beam were carried out according to the detection principle.The size and structure of the sample flow chamber were designed according to the requirements of detection accuracy and particle size detection range.The mechanical packaging housing was designed according to the optical path structure to fix the optical path components.Secondly,the signal processing circuit of the particle size sensor was designed,including the photoelectric conversion circuit,the constant power drive circuit of the light source,the integral feedback stabilizing circuit,the second-stage amplification circuit,the AD acquisition circuit,and the linear power module.The stability and noise reduction problems of the photoelectric conversion circuit were emphasized,and theoretical analysis and simulation were carried out to provide the basis for selecting the key component parameters.To solve the problem of different circuit output voltage amplitudes caused by different oil conditions of the measured oil,an integral stabilizing feedback circuit was designed to adjust the light source power at all times to ensure that the instrument processes the circuit output stable amplitude when measuring different types of oil.Due to the insufficient amplification factor of the photoelectric conversion circuit,a second-stage amplification circuit was designed to detect small particles,and an integral stabilizing feedback circuit was also added to the second-stage amplification circuit to reduce the output amplitude fluctuation problem caused by multi-stage amplification and circuit drift.For particle counting,an AD acquisition circuit was designed instead of the traditional comparator circuit,and the collected particle pulse signal was sent to the single-chip microcomputer for comparison and counting through software to determine the particle size pollution level.Finally,experimental testing was conducted on the designed particle size sensor.The threshold voltage corresponding to the particle size was calibrated by measuring the configured monodisperse standard sample.Then,the calibrated threshold voltage was used to measure the polydisperse oil-based MTD particle standard substance,and it was compared with the standard substance quantity table;Under the determined working flow rate,the flow rate was varied by counting the dispersed reference materials,and the flow rate limit at the working flow rate was obtained.Finally,it was concluded that the sensor designed in this project has good accuracy and stability.