An on-line imaging sensor based on magnetic deposition and flowing dispersion for wear debris feature monitoring

Abstract

Sensors that can real-time monitor the wear particles suspended in lubricating oil are of great value in evaluating the health state of various machines (e.g., engines, transmissions). Here we report an on-line imaging sensor with a new structure, operating with magnetic deposition and flowing dispersion methods. A highly divergent magnetic field is generated by the cage electromagnet to collect ferromagnetic particles which will then disperse via the flow field in the disc-like channel. Wear particles in the chain- and separated-form are imaged respectively by the imaging module to acquire four debris features (concentration, size distribution, shape, and colour). We demonstrated that the developed sensor offers a low size detection limit (1–10 μm), a broad concentration-sensing range (2–200 ppm), and a high throughput (∼100 ml/min). Beyond that, the type and material of wear debris can also be identified in the test, utilising the shape and colour features getting by the sensor. This sensor shows promise for use in monitoring the machine health condition and studying the wear mechanism of surfaces.