Oil Particle Detection Method And Circuit

The amount of metallic debris in the lubricant oil reflects a lot of information about the state of mechanical equipment operation, as an important indicator to judge whether the machine operate normally, therefore detection and analysis of metal wear particles in lubricant oil is a very important engineering application.The inductive oil debris detection sensor is a class of on-line metallic particle monitoring sensor installed in the pipe of the circulating lubricant oil, bass on the coupling relation between the metal abrasive particle and inductor coil. When the metal wear particle pass through the inductive oil debris detection sensor, it outputs induction signal related to metallic debris. The amplitude of induction signal is proportional to the mass of metallic particle, thus to estimate the content of metal grains in the oil accurately, analysis the wear condition of machinery and equipment.This thesis design three kinds of the inductive oil debris detection sensor, and construct mathematical model to analyze their working principles. the inductive wear particle detection sensor is too sensitive to be interfered by noise and vibration environment, the inductive signal of the metal grains are often flooded by the noise and interference, which seriously affects the detection results of the inductive wear particle detection sensor. In order to extract the small inductive signal from a severe mixed signal, this paper firstly discusses the processing of anti-interference of the oil debris detection system, and then proceed to the study of the detection circuit.Against to inductive signal characteristics of three kinds of inductive wear particle detection sensor, respectively design low-noise signal detection device, Include the design of the dual high-precision phase modulation signal source、the low-noise preamplifier、the precision rectifier circuit、the synchronous detection circuit and the later stage filtering amplifier. In the experiment, the three-coil inductive wear particle detection sensor detect the ferromagnetic debris accuracy up to200μm,and determine the ferromagnetic material of particle through the phase of the inductive signal (The phase of the ferromagnetic debris signal contrary to the non-ferromagnetic debris). With back-end A/D converter module、DSP data processing module, the ferromagnetic particle detection accuracy of three-coil inductive wear particle monitoring system is up to100μm, statistic and analysis the content of ferromagnetic particles, and ultimately achieve estimating the operating conditions of rotating machinery.