ASTM D4741 Measuring Viscosity at High Temperature and High Shear Rate by Tapered-Plug Viscometer
6. Apparatus
6.1 Ravenfield Tapered Plug High Shear Viscometer - Model BE (single speed) or BS (multispeed). The viscometer uses a rotating tapered plug in a matched stator.
6.2 Calibration Weight, (supplied with instrument).
6.3 Wash Bottle, fitted with metal tip (supplied with instrument).
6.4 Thermostatically Controlled Heating Bath, with fluid circulator.
6.5 Temperature Measuring Instrument, having a precision not worse than +/-0.2°C at 150°C.
6.6 Vacuum Pump, with suitable liquid trap.
7. Materials
7.1 Newtonian Calibration Oils, CEC Reference Oils RL 102-107.
7.2 Non-Newtonian Check Oil, CEC Reference Oil RL 90.
7.3 Washing Solvent, ASTM precipitation naphtha as specified in Test Method D91 or a solvent of similar volatility.
NOTE 1 - Warning: Extremely flammable. Vapors may cause flash fire. See Annex A1.
8. Sampling
8.1 Test oils that are visually free from haze and particulates need not be filtered before evaluation. A sample must be free of particles larger than 3 µm. If after filtration through a filter of pore size 3 µm, a heavy concentration of smaller particles is still visible, it is wise at least to reduce their concentration by further filtration. This will reduce the possibility of the particles wedging in the measurement gap and so causing erosion of the rotor/stator or erroneous readings. Do not filter formulated oils through pore sizes below 1 µm because certain lubricant additives could be removed.
