Inductive particle detection system for real-time monitoring of metals in airborne particles

Abstract

A novel inductive particle detection system was developed for a real-time monitoring of metals in airborne particles which cannot be measured using current commercial portable devices. The detection system consists of particle sampling, particle sensing, oil circulation sections and signal processing circuit. Airborne particles of different sizes enter the system and are classified according to their sizes in the particle sampling section. Particles larger than 5 µm are collected on the oil surface and passed through the particle sensing section along with the oil circulating throughout the system. The particle sensing section was realized using a 3D multilayer solenoid connected to a high-precision inductance meter. The performance of each section was first evaluated, and then the overall performance of the system was evaluated. The results show that ferrous and nonferrous metals in airborne particles can be detected and differentiated using proposed system with minimum detectable size of 5–10 µm for Fe and 50–60 µm for Cu particles. In addition, the number concentration of Fe particles was converted and compared with the reference number concentrations measured by high-precision commercial instrument, under the metal particle generation condition. The comparison results of the system show good agreement at concentrations within its detectable range, up to 200 #/L. The proposed system and design concept demonstrated here can be widely used for the real-time and extensive monitoring of airborne metal particles in industrial workplaces.