Determination of metal particles in oil using a microfluidic chip-based inductive sensor

A new microfluidic chip is reported to detect wear particles in oil, and a dual-coil design was studied to improve the sensitivity. Compared to the conventional single-coil inductive sensor, the dual coil is based on the principle of mutual inductance and has a small basic inductance. Therefore, it does not hide the millimeter-size inductive pulses. A series of particles of various sizes were employed to evaluate the performance. Due to the small inductance and the zero distance between wear particles and the coil, the sensitivity of the inductive sensor was greatly improved as iron particles from 5-10 mu m in diameter were detected. This simple and economical device is expected to provide useful guidance to improve microfluidic inductive sensors for monitoring and fault detection in industry.