ASTM D5133 low temp, low shear rate, viscosity/temp dependence of lubricants
ASTM D5133 standard test method for Low Temperature, Low Shear Rate, Viscosity/Temperature Dependence of Lubricating Oils Using a Temperature-Scanning Technique
13. Procedure
13.1 Bath Programming:
13.1.1 Prepare to use special cooling program shown in Table 2 for testing unknown oils on programmable liquid cooling bath. Follow equipment manufacturer's instructions.
13.1.2 Set cooling bath to hold at -5°C until test is begun.
13.2 Follow equipment manufacturer's instructions for entering identification of samples and sample cells into computer program.
NOTE 8 - It is helpful to occasionally check operator technique and the functioning of the bath and other equipment by including and running a Gelation Index Reference oil having a known value of Gelation Index and Gelation Index temperature.
13.3 Follow Section 12 to properly pre-heat the oils in preparation for analysis.
NOTE 9 - These pre-heating steps should be followed precisely as described.
13.4 Zero the viscometer head according to equipment manufacturer's instructions.
13.5 Insert matching, room-temperature rotor into the appropriate stator in preparation for joining the test cell to the adapter/viscometer head support and proceed immediately to remaining steps for preparation and cold-bath immersion.
13.6 Place test cell into test cell adapter according to manufacturer's instructions, taking care that no air bubbles are clinging to the bottom of the rotor when the cell and adapter are affixed to the viscometer head. If bubbles are noted after assembly, tip the assemblage to the side until the bubbles slide off the rotor bottom and hold upright again to permit bubbles to rise to the surface.
13.7 Fasten test cell and adapter to viscometer head after hooking rotor shaft to viscometer motor shaft.
13.8 Place the assembled test cell and viscometer head onto the programmable liquid bath. The samples should equilibrate in the cold bath at least 15 min but no longer than 30 min.
13.9 Set up the dry gas flow at approximately 10 mL/min. for each test cell.
13.10 Set the viscometer speed to 0.3 r/min.
13.11 Within 30 min of the time the first sample has been immersed in the bath, turn on the computer program and simultaneously initiate:
13.11.1 The cooling program on cold-bath and
13.11.2 Data recording on computer according to manufacturer's instructions.
13.12 At the conclusion of the test, use the computer program for data analysis and determination of critical pumpability temperature, Gelation Index, and Gelation Index temperature according to the manufacturer's directions.
NOTE 10 - It is necessary to complete Section 11 for calibration of viscometer and cells before using the computer program or the program will not be able to accept information generated during the analysis of test oils.
