Research On The Detection Of Ferromagnetic Metal Particles In Oil

The state detection of lubricating oil is an important part to ensure the safe and stable operation of mechanical equipment.Through analyzing the status of oil accurately the mechanical failure can be predicted.Thus,engineers can start the maintenance in time,which can greatly reduce the maintenance cost,reduce the loss and improve the production efficiency.Iron and its alloy materials are the important components of mechanical equipment.When the mechanical parts wear,the ferromagnetic metal wear particles will appear in the lubricating oil circuit and flow with the oil.Therefore,the degree of wear of mechanical equipment can be get by the detection of the oil.This can achieve the purpose of ensuring safe and stable production.The goal of this subject is to develop a practical instrument for detecting ferromagnetic metal particles in oil.The reverse double supply inductance sensor is selected.In this paper,the influence parameters of metal particle sensor in oil are studied.This paper analyzes the factors that affect the detection response of the sensor and the method to reduce the error and improve the stability.Through the simulation software,the finite element two-dimensional axisymmetric model of the sensor is established.The basic design parameters of the sensor which can produce large output are determined,which is the theoretical basis for the detection of the sensor.According to the theoretical basis of the simulation model,the metal particle sensor and related electrical circuit is designed and manufactured.The performance of the sensor is verified by experiments.Finally,a data acquisition system based on MCU is designed to collect the output of the sensor.The research and design of the metal particle detector in the oil is completed.Through the preliminary experiment,the metal particle detector can detect the ferromagnetic metal particles above 100μm.The main innovations of this paper are as follows:(1)In the COMSOL simulation experiment,a new "set outside" model is established which is different from the traditional "press from both sides" basic model.And the basic model and the new model are verified by physical experiments.(2)The AC power supply with adjustable frequency from 2400 Hz to 3000 Hz is designed,which is used as the excitation supply of the sensor.(3)The design of traditional unity gain filter is improved,and the design of bandpass filter with gain is realized.While simplifying the circuit structure,the better filter and amplification effect are obtained.(4)The data acquisition system is designed.The sensor is combined with the data acquisition system,which is separated from the measuring instrument(such as oscilloscope,inductance parameter measuring instrument and optical instrument).A complete set of instruments has been basically completed.