13. Cleaning of Viscometer
13.1 Between successive determinations of kinematic viscosity, clean the viscometer thoroughly by several rinsings with the sample solvent, followed by the drying solvent (see 7.3). Dry the tube by passing a slow stream of filtered dry air through the viscometer for 2 min or until the last trace of solvent is removed.
13.2 Periodically clean the viscometer with the cleaning solution (Warning - see 7.1), for several hours to remove residual traces of organic deposits, rinse thoroughly with water (7.4) and drying solvent (see 7.3), and dry with filtered dry air or a vacuum line. Remove any inorganic deposits by hydrochloric acid treatment before the use of cleaning acid, particularly if the presence of barium salts is suspected. (Warning - It is essential that alkaline cleaning solutions are not used as changes in the viscometer calibration can occur.)
14. Calculation
14.1 Calculate each of the determined kinematic viscosity values, v1 and v2, from the measured flow times, t1 and t2, and the viscometer constant, C, by means of the following equation:
v1,2 = C•t1,2
where:
n1,2 = determined kinematic viscosity values for v1 and v2, respectively, mm2/s,
C = calibration constant of the viscometer, mm2/s2, and
t1,2 = measured flow times for t1 and t2, respectively, s.
Calculate the kinematic viscosity result, v, as an average of v1 and v2 (see 11.2.3 and 12.5.1).
14.2 Calculate the dynamic viscosity, n, from the calculated kinematic viscosity, v, and the density, ρ, by means of the following equation:
n = v x ρ x 10-3
where:
n = dynamic viscosity, mPa•s,
ρ= density, kg/m3, at the same temperature used for the determination of the kinematic viscosity, and
v = kinematic viscosity, mm2/s.
14.2.1 The density of the sample can be determined at the test temperature of the kinematic viscosity determination by an appropriate method such as Test Methods D1217, D1480, or D1481.
15. Expression of Results
15.1 Report the test results for the kinematic or dynamic viscosity, or both, to four significant figures, together with the test temperature.
16. Report
16.1 Report the following information:
16.1.1 Type and identification of the product tested,
16.1.2 Reference to this test method or a corresponding international standard,
16.1.3 Result of the test (see Section 15),
16.1.4 Any deviation, by agreement or otherwise, from the procedure specified,
16.1.5 Date of the test, and
16.1.6 Name and address of the test laboratory.
