A novel inductance/capacitance microfluidic chip for the multi-contamination detection in marine hydraulic oil

Abstract

Micro particles in marine machinery systems contain vital information of the device working status. Statistics show that 75% of hydraulic system mechanical failures are caused by oil contamination. During the normal working condition of hydraulic equipment, the particles in hydraulic oil have a constant concentration and small size. When abnormal wear occurs, the concentration and the size of particles will increase rapidly. Compared with conventional hydraulic system, marine hydraulic system works in a harsh environment, so it requires high clean hydraulic oil. The qualitative detection and quantitative counting of oil particle contamination is of important significance to the condition monitoring and fault diagnosis of the marine machineries. A novel inductance/capacitance microfluidic chip is presented for the detection of multi-contamination in marine hydraulic oil in this paper. The microfluidic chip consists of d a straight microchannel with two embedded single-layer inductance coils, which is not only a micro inductor to detect the inductance changes of the oil but also a micro capacitor to detect the capacitance changes of the oil. In the inductance experiments, iron particles in the size of in the size of 80 to 90 μm and copper particles in the size of 150 to 160 μm in the oil are successfully detected and the inductance signals of the two type particles are distinguishable. In the capacitance experiments, water droplets in the size of 180 to 190 μm and bubbles in the size of 240 to 260 μm in the hydraulic oil are detected and their signals are also distinguishable. Based on the inductance/capacitance microfluidic chip, an integral micro detection system is presented. The micro detection system is expected to provide supports for fault prognostics and diagnosis in marine hydraulic systems.