Lubricant oil condition monitoring using a scattering-free single-wavelength optical scheme

A simple and low-cost optical setup can be used for monitoring online the condition of lubricant oil in big machineries, as an action of preventive maintenance. The total acid number and the water content, as indicators of the lubricant oil quality, can be assessed by means of an integrating sphere for achieving scattering-free absorption measurements. For each indicator, spectroscopy showed that a peculiar wavelength is enough for predicting with good accuracy the value of the indicator. © 2014 SPIE.