METHOD FOR DETERMINING TEMPERATURE OF BEGINNING OF CHANGE IN INDICATORS OF THERMAL OXIDATIVE STABILITY AND MAXIMUM OPERATING TEMPERATURE OF LUBRICANTS Russian patent published in 2020 - IPC G01N25/02 G01N25/22 G01N33/30 G01K11/00 

FIELD: technological processes.

SUBSTANCE: invention relates to technology of determining indicators of thermal oxidative stability of lubricants. Disclosed is a method in which lubricant samples are thermostated at a minimum of three selected temperatures in the presence of air with mixing of constant weight for a period of time, at regular intervals the sample of the oxidised lubricant is weighed, part of sample is photometered and optical density, evaporation and coefficient of thermo-oxidative stability are determined. According to said indicators of thermal oxidative stability, calculating the amount of heat energy absorbed by oxidation products, evaporation products, and total absorbed heat energy during temperature control of lubricant, which is determined by product of temperature value, multiplied by test time and value of corresponding thermo-oxidative stability index. Decimal logarithms of absorbed heat energy are calculated for each index and graphical dependencies of decimal logarithm of absorbed heat energy of thermo-oxidative stability index on decimal logarithm of time and test temperature are plotted. These relationships are used to determine values of decimal logarithm of absorbed thermal energy of thermo-oxidative stability index at given decimal logarithm of test time and test temperatures. Values of the decimal logarithm of the test time are also determined at a given value of the decimal logarithm of the absorbed heat energy of the thermo-oxidative stability at each temperature. Besides, values of decimal logarithm of time of beginning of change of decimal logarithm of absorbed thermal energy of thermo-oxidative stability at each temperature are determined. Based on the obtained data, additional graphic relationships are plotted for each index. Dependence of the decimal logarithm of the absorbed heat energy of the thermo-oxidative stability value on the test temperature is used to determine the temperature of the beginning of the change in the decimal logarithm of the absorbed heat energy at a given decimal logarithm of the test time. Dependence of decimal logarithm of test time on test temperature with given value of decimal logarithm of absorbed thermal energy of thermo-oxidative stability is used to determine maximum operating temperature of analyzed lubricant, and based on the decimal logarithm of the beginning of the change in the decimal logarithm of the absorbed heat energy of the thermo-oxidative stability index from the test temperature, the beginning of the change in the decimal logarithm of the absorbed heat energy is predicted for other temperatures.

EFFECT: high information content of lubricant control for comparison of their quality and selection.

1 cl, 3 dwg, 1 tbl