ASTM D5018 Standard Test Method for Shear Viscosity of Coal-Tar and Petroleum Pitches
5. Apparatus
5.1 Viscometer - A rotational viscometer capable of measuring viscosity in the range of about 5 mPa·s (cP) to 15 000 mPa·s (cP); the viscometer should be equipped with the appropriate accessories to allow measurements up to about 230 °C. The essential instrumentation required providing the minimum rotational viscometer analytical capabilities include (see Practice E1953):
5.1.1 Drive motor, to apply a unidirectional rotational displacement to the specimen of 0.3 r/min to 60 r/min constant to +/- 1 %.
5.1.2 Force sensor, to measure the torque developed by the specimen to within +/- 1 %.
5.1.3 Coupling shaft, or other means to transmit the displacement from the motor to the specimen.
5.1.4 Rotational element, spindle, or rotor, of the shape shown in Fig. 1, to fix the specimen between the coupling shaft and a stationary position.
5.1.5 Specimen container, chamber, or cup, to contain the test specimen during testing.
NOTE 1 - Rotor and cup are matched in size so that shear rate is fixed and known.
5.1.6 Data collection device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both. The minimum output signals required for rotational visocity are torque, rotational speed, temperature, and time.
5.1.7 Auxiliary instrumentation considered useful in conducting this test method includes:
5.1.7.1 Data analysis capability, to provide viscosity, stress, or other useful parameters derived from measured signals.
5.1.7.2 Stand, to support, level, and adjust the height of the drive motor, shaft, and rotor.
5.1.7.3 Level, to indicate the vertical plumb of the drive motor, shaft, and rotor.
5.2 Sample Temperature Control System - Any device capable of maintaining the sample test temperature within limits of +/- 1.0 °C while allowing viscosity measurements.
5.3 Thermometer - ASTM precision thermometer 2C, having a range of -5 °C to 300 °C.
5.4 Hot Plate - Any hot plate with adjustable temperature control and surface temperature indication (to prevent sample overheating).
5.5 Calibration Fluids - A series of calibrated fluids that cover the viscosity range of approximately 100 mPa·s (cP) to 15 000 mPa·s (cP) at temperatures up to 150 °C.
NOTE 2 - Calibration fluids are available from the rotational viscometer supplier.
6. Reagents and Materials
6.1 Cleaning Solvent - Any solvent capable of dissolving pitch, (suitable solvents are quinoline or creosote oils).
6.2 Rinsing Solvents - Toluene and acetone are used for final rinsing after initial cleaning.
