METHOD OF DETERMINING MAXIMUM PERMISSIBLE PERFORMANCE INDICATORS OF LUBRICANTS Russian patent published in 2019 - IPC G01N25/02 G01N25/12 G01N33/30 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the technology of determining the quality of oil products and can be used to control thermal oxidative stability and temperature range of serviceability of lubricants. Disclosed is a method of determining maximum permissible parameters of operability of lubricants, including heating sample and conducting tests in two cycles of temperature change with stepped increase and stepped reduction. At that, at equal intervals of time at each temperature, the oxidized lubricant material sample is weighed, the evaporated lubricant mass and the evaporation rate are determined, part of the oxidized sample is sampled for photometry and optical density is determined. Thermo-oxidative stability coefficient is calculated from the obtained data. According to values of thermo-oxidative stability values obtained for cycles of increase and decrease of test temperature, additionally determining value of heat energy absorbed by oxidation products, products of evaporation, and total heat energy absorbed by products of oxidation and evaporation at each temperature, as product of temperature value by time and value of thermo-oxidative stability, calculating decimal logarithms of heat energy absorbed by oxidation products, evaporation products, and total heat energy absorbed by these products, graphical dependences of the decimal logarithm of heat energy on the decimal logarithm of test time are plotted, from which coordinates of the intersection of these dependences are determined, characterizing maximum permissible parameters of lubricant serviceability, including test time to maximum permissible values of optical density, evaporation and coefficient of thermo-oxidative stability and maximum permissible values of heat energy absorbed by products of oxidation, evaporation, and total heat energy absorbed by products of oxidation and evaporation, by which lubricants are compared.

EFFECT: high information value of monitoring serviceability of lubricants owing to taking into account heat energy absorbed by the lubricant.

1 cl, 3 dwg, 1 tbl