An Inductive Coulter Counting Device for Online Monitoring of Wear Debris in Lubricant

A device based on an inductive Coulter counting principle to detect metal particles in lubrication oil is presented. The device detects the passage of ferrous and nonferrous particles by monitoring inductance change in a coil. First, the sensing principle is demonstrated at the mesoscale using a solenoid. Next, a microscale device is developed using a planar coil. The device is tested using iron and aluminum particles ranging from 80μm to 500μm. The testing results show the device is capable of detecting and distinguishing ferrous and nonferrous metal particles in lubrication oil, such particles can be indicative of potential machine faults in rotating and reciprocating machinery. The design concept demonstrated here can be extended to a microfluidic device for real-time monitoring of ferrous and nonferrous wear debris particles.