METHOD FOR DETERMINING THERMAL OXIDATIVE STABILITY OF LUBRICANTS Russian patent published in 2005 - IPC

FIELD: measurement technology; material quality control.

SUBSTANCE: method involves testing lubricant material sample in presence of air with stirring constant volume under optimum temperature selected with its dependence on lubricant base and a group of operational properties during a time interval characterizing equal oxidation degree taken into account. Acting in equal time intervals, absorption coefficient is measured for luminous flow absorbed by oxidized lubricant material by applying photometry methods. Viscosity and thermal oxidative stability coefficient K_tos are calculated by using relationship like K_tos = K_a μ₀/μ_in, where K_a is the luminous flow absorption coefficient of oxidized lubricant material; μ₀ and μ_in are the viscosities of oxidized and initial state lubricant, respectively. Graphic dependence of thermal oxidative stability coefficient against luminous flow absorption coefficient of oxidized lubricant material is plotted. Rate of oxidation end products release and their influence upon tested lubricant viscosity growth is determined from plot slope angle tangent with respect to abscissa axis after inflection point. The inflection point coordinates are used for determining the starting point the oxidation end products release begins.

EFFECT: high reliability of estimation method.

4 dwg