METHOD OF CLASSIFICATION OF LUBRICANTS ON PARAMETERS OF THERMOXIDATING STABILITY Russian patent published in 2017 - IPC G01N33/30 

FIELD: chemistry.

SUBSTANCE: in the process, a lubricant sample is tested in the presence of stirring air, a constant volume, at a minimum of three temperatures, selected depending on the base substrate, purpose and group of performance properties, for a time indicative of the same oxidation state. At regular intervals, an oxidised lubricant sample is taken and the oxidation process is evaluated. According to the invention, the oxidised lubricant sample is weighed, the mass of the evaporated lubricant and the volatility factor are determined as the ratio of the mass of the evaporated lubricant to the mass before testing. A portion of the sample is taken for photometry and the determination of the optical density of the oxidized lubricant. According to the obtained data, the thermooxidative stability index as the sum of the optical density and the coefficient of volatility are determined. The graphical dependencies of the thermooxidative stability index are plotted against time, at a minimum, at three test temperatures, which determine the potential resource characterising the time to reach the specified value of the thermooxidative stability index at each test temperature. Based on these data, the graphic dependencies of the potential resource on the test temperature are determined, which determine the rate of change of the potential resource from the test temperature and the critical temperature, and the classification of lubricants is established from the critical temperature and the rate of change of the potential resource at the selected test temperatures.

EFFECT: improvement of the system of classification of lubricants, as well as the implementation of an informed choice of lubricants for engines of varying loading with the maximum life.

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