ASTM D7279 Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids by Automated Houillon Viscometer
3. Summary of Test Method
3.1 The kinematic viscosity is determined by measuring the time taken for a sample to fill a calibrated volume at a given temperature. The specimen is introduced into the apparatus and then flows into the viscometer tube which is equipped with two detection cells. The specimen reaches the test temperature of the viscometer bath and when the leading edge of the specimen passes in front of the first detection cell, the automated instrument starts the timing sequence. When the leading edge of the specimen passes in front of the second detection cell, the instrument stops timing the flow. The time interval thus measured allows the calculation of the kinematic viscosity using a viscometer tube constant determined earlier by calibration with certified viscosity reference standards.
3.2 The kinematic viscosity is calculated using the formula:
ν = C x t
where:
ν = the kinematic viscosity in mm2/s,
C = the viscometer tube constant in mm2/s, and
t = the flow time in s measured during the test.
4. Significance and Use
4.1 Many petroleum products and some non-petroleum products are used as lubricants in the equipment, and the correct operation of the equipment depends upon the appropriate viscosity of the lubricant being used. Additionally, the viscosity of many petroleum fuels is important for the estimation of optimum storage, handling, and operational conditions. Thus, the accurate determination of viscosity is essential to many product specifications.
4.2 The viscosity of used oils is a commonly determined parameter in the oil industry to assess the effect of engine wear on the lube oils used, as well as the degradation of the engine parts during operation.
4.3 The Houillon viscometer tube method offers automated determination of kinematic viscosity. Typically a sample volume of less than 1 mL is required for the analysis.
