Oil Metal Debris Detection Sensor Using Ferrite Core and Flat Channel for Sensitivity Improvement and High Throughput

A high throughput and high sensitivity sensor for detection of oil metal debris is presented. The sensor is mainly composed of a planar coil, a ferrite core and a flat channel. The adoption of flat channel can increase the throughput without sacrifice of sensitivity. The comparative experiments show that the ferrite core not only eliminates the phenomenon of multiple pulse peaks for detecting individual metal particle in the flat channel, but also can improve the sensitivity of inductance detection and resistance detection. For detecting 130-140 μm iron particles, the inductance amplitude and SNR (signal-to-noise ratio, the SNR is the amplitude divided by the interference noise) of sensor with ferrite core are 1.17 times and 1.22 times higher than those of sensor without ferrite core, respectively. For detecting 160-170 μm copper particles, the inductance amplitude and SNR of sensor with ferrite core are 1.24 times and 1.28 times higher than those of sensor without ferrite core, respectively, and the resistance amplitude and SNR of sensor with ferrite core are 1.09 times and 1.07 times higher than those of sensor without ferrite core, respectively. In addition, the introduction of resistance detection can increase the ability of sensor to detect non-ferromagnetic metal particles. We can detect iron particles with diameter of 40 μm onwards and detect copper particles with diameter of 90 μm onwards using the sensor with ferrite core combined with inductance and resistance detection methods. This work improves the throughput of microfluidic high-precision detection, which can provide technical support for large-flow oil detection.