ASTM D2170 standard test method for kinematic viscosity of asphalts (bitumens)
6. Apparatus
6.1 Viscometers, capillary-type, made of borosilicate glass, annealed, suitable for this test are described in Annex A2 and include the following:
6.1.1 Cannon-Fenske viscometer for opaque liquids,
6.1.2 Zeitfuchs cross-arm viscometer,
6.1.3 Lantz-Zeitfuchs viscometer,
6.1.4 BS U-Tube modified reverse flow viscometer.
6.2 Calibrated viscometers are available from commercial suppliers. Details regarding calibration of viscometers are given in Annex A3.
6.3 Thermometers - Calibrated liquid-in-glass thermometers of an accuracy after correction of 0.04°F (0.02°C) can be used or any other thermometric device of equal accuracy. ASTM Kinematic Viscosity Thermometers 47F and 47C and IP 35F and 35C are suitable for use at 140°F (60°C) and ASTM Kinematic Viscosity Thermometers 110F and 110C are suitable for use at 275°F (135°C).
6.3.1 The specified thermometers are standardized at "total immersion", which means immersion to the top of the mercury column with the remainder of the stem and the expansion chamber at the top of the thermometer exposed to room temperature. The practice of completely submerging the thermometer is not recommended. When thermometers are completely submerged, corrections for each individual thermometer based on calibration under conditions of complete submergence must be determined and applied. If the thermometer is completely submerged in the bath during use, the pressure of the gas in the expansion chamber will be higher or lower than during standardization, and may cause high or low readings on the thermometer.
6.3.2 It is essential that liquid-in-glass thermometers be calibrated periodically using the technique given in Test Method E 77 (see Appendix X1).
6.4 Bath - A bath suitable for immersion of the viscometer so that the liquid reservoir or the top of the capillary, whichever is uppermost, is at least 20 mm below the upper bath level, and with provisions for visibility of the viscometer and the thermometer. Firm supports for the viscometer shall be provided, or the viscometer may be an integral part of the bath. The efficiency of the stirring and the balance between heat losses and heat input must be such that the temperature of the bath medium does not vary by more than more or less 0.05°F (more or less 0.03°C) over the length of the viscometer, or from viscometer to viscometer in the various bath positions at 140°F (60°C). The variation at 275°F (135°C) must not exceed more or less 0.05°F (more or less 0.03°C).
NOTE 2 - Distilled water is a suitable bath liquid for determinations at 140°F (60°C). USP White Oil with a flash point above 420°F (215°C) has been found suitable for determinations at 275°F (135°C). The flash point is determined in accordance with Test Method D92.
6.5 Timer - A stop watch or other spring-activated timing device graduated in divisions of 0.1 s or less and accurate to within 0.05 % when tested over intervals of not less than 15 min.
6.6 Electrical Timing Devices may be used only on electrical circuits the frequencies of which are controlled to an accuracy of 0.05 % or better.
6.6.1 Alternating currents, the frequencies of which are intermittently and not continuously controlled, as provided by some public power systems, can cause large errors, particularly over short timing intervals, when used to actuate electrical timing devices.
