METHOD FOR DETECTING PARTICLE CONCENTRATION

PROBLEM TO BE SOLVED: To provide a particle concentration detection method, capable of suppressing detection error resulted from the component ratio of particles in a liquid in detection of a particle concentration in the liquid based on a transmitted light quantity. SOLUTION: Visible light is emitted from a visible light emission part 12a1 toward lubricating oil, and a visible light transmittance (visible light transmission quantity I1/visible light emission quantity Io1×100) at that time is calculated. Infrared light is emitted from an infrared light emitting part 12a2 toward the lubricating oil, and an infrared light transmittance (infrared light transmission quantity I2/infrared light emitting quantity Io2×100) at that time is calculated. Based on an equation showing the relation of the ratio of visible light transmittance to infrared light transmittance (visible light transmittance T1/ray transmittance T2) with the particle concentration of the lubricating oil, more specifically, based on an approximation of particle concentration using the logarithm of the ratio of transmittance as a variable, the particle concentration of the lubricating oil is detected. COPYRIGHT: (C)2007,JPO&INPIT