Comparison of Spectro LNF Q200 to Standard Kinematic Viscosity Measurements
To assess lubricant condition, laboratories commonly measure oil viscosity as the ratio of viscous force to inertial force, using kinematic capillary tube viscometers. Another methodology, using Poiseuille’s law, measures dynamic (absolute) viscosity from fundamental parameters when applied to fluid flow through an analysis cell after applying direct imaging particle counting technology to the determination of fluid viscosity. This makes it possible to obtain dynamic viscosity for the oil under test in addition to particle classification information. This paper explains the theory and use of applying Poiseuille’s law to measure viscosity, and presents results of tests comparing typical kinematic capillary tube measurements to those using this novel method using the Spectro LNF 200.