METHOD TO DETERMINE FLASH POINT OF LUBRICATING OILS Russian patent published in 2021 - IPC G01N25/52 G01N33/30 

FIELD: test technology.

SUBSTANCE: invention relates to the field of materials testing by means of heating, in particular to the technology of determining the flash point temperature of lubricating oils without use of firing of vapors, and can be used in evaluation of operational characteristics of commercial and operating lubricants. Disclosed is a method for determining flash point of lubricating oils, in which samples of lubricating oil of constant weight are thermostatically controlled at atmospheric pressure without mixing for a period of time, providing evaporation of the installed mass of lubricating oil. After equal time intervals of the test, the temperature-controlled sample is weighed, the weight of evaporated lubricating oil is determined, graphical dependencies of the weight of evaporated lubricating oil on time and temperature of temperature control are plotted. Obtained dependences are used to determine decimal logarithms of thermal energy absorbed by the mass of evaporated oil determined by the product of temperature for the set time and weight of the evaporated oil during that time. Graphical dependences of the decimal logarithm of heat energy absorbed by the evaporated oil mass are plotted against the decimal logarithm of the set time and temperature of temperature control. Values of decimal logarithms of thermal energy are determined at crossing of these dependencies with axis of ordinates. Constructing the graphical dependence of these values on the temperature control temperature, from which the temperature of the beginning of the change in the decimal logarithm of heat energy is determined. Also, at least three constant values of decimal logarithm of heat energy for analyzed oil are determined, from which values of decimal logarithms of time for achievement of selected constant values of decimal logarithm of heat energy for investigated temperatures of temperature control are determined. Graphical dependences of the decimal logarithm of time for achieving selected constant values of the decimal logarithm of heat energy absorbed by the mass of evaporated lubricating oil are plotted against temperature of thermal conditioning, and from points of intersection of given relationships with the axis of abscissa determining flash points and their dependence on the accepted constant values of the decimal logarithm of heat energy, based on which graphical dependence of constant values of decimal logarithm of heat energy absorbed by mass of evaporated oil is plotted, from the flash temperature, from which the effect of the decimal logarithm of heat energy on the flash point is determined, which enables to justify the choice of the value of the decimal logarithm of heat energy for comparison of different lubricating oils.

EFFECT: high accuracy of the method of determining flash point of lubricating oils by taking into account heat energy absorbed by the mass of evaporated oil and information on the temperature of the onset of evaporation processes.

1 cl, 15 dwg