Online Wear Particle Detection Sensors for Wear Monitoring of Mechanical Equipment—A Review

Online wear particle detectors have been widely studied due to their ability to monitor the wear state of machines, and to help to prevent serious mechanical failures caused by excessive wear of components. This paper presents a review of the state-of-the-art wear debris detectors based on different principles. That mainly includes optical/imaging particle detectors, electrical particle detectors, ultrasonic particle detectors and magnetic debris detection sensors. Meanwhile, the characteristics and the performance (sensitivity, maximum flow rate, and the detectable information) of each type of sensor are detailed discussed. In conclusion, the optical/imaging and magnetic debris detectors have become promising technologies in the field of wear monitoring. Meanwhile, that the rapid extraction algorithm and three-dimensional reconstruction method of wear debris for optical/imaging debris detectors, and improving the sensitivity and detectability of magnetic debris detectors are the two important research contents in the field. Besides that, it can be predicted that the integrated wear monitoring system that can collect multiple wear-information in-situ, and the intelligent wear particle detector that have the ability of wear monitoring, wear evaluation and fault warning are the main research directions in the future.