Brookfield RVDV-II+Pro - II.11 Time Modes for Viscosity Measurement

Brookeld Engineering Labs., Inc. Page 21 Manual No. M/03-165-D0410
3. The process of selecting a spindle and speed for an unknown uid is normally trial and error. An
appropriate selection will result in measurements made between 10-100 on the instrument
% torque scale.
Two general rules will help in the trial and error process.
1) Viscosity range is inversely proportional to the size of the spindle.
2) Viscosity range is inversely proportional to the rotational speed.
To measure high viscosity, choose a small spindle and/or a slow speed. If the chosen spindle/
speed results in a reading above 100%, then reduce the speed or choose a smaller spindle.
Experimentation may reveal that several spindle/speed combinations will produce satisfac
-
tory results between 10-100%. When this circumstance occurs, any of the spindles may be
selected.
Non-Newtonian uid behavior can result in the measured viscosity changing if the spindle
and/or speed is changed. See our publication, “More Solutions to Sticky Problems,” for more
detail.
Turn on motor.
Allow time for the indicated reading to stabilize. The time required for stabilization will depend
on the speed at which the Viscometer is running and the characteristics of the sample uid. For
maximum accuracy, readings below 10% should be avoided.
Record values.
4. Press the
MOTOR ON/OFF/ESCAPE key and turn the motor “OFF” when changing a spindle or
changing samples. Remove spindle before cleaning.
5. Interpretation of results and the instrument’s use with non-Newtonian and thixotropic materials
is discussed in the booklet, “More Solutions to Sticky Problems”, and in Appendix C, Variables
in Viscosity Measurements.
II.11 Time Modes for Viscosity Measurement
The Time Modes
allow the viscometer user to implement the unattended Time to Stop and Time to
Torque capabilities of the DV-II+Pro Viscometer. These features will allow the user to set up the
viscometer (i.e. select spindle and speed) and then record readings for a xed period of time (Time
to Stop) or until a set torque value is attained (Time to Torque). When timing begins, a message will
be displayed showing time remaining (or time elapsed) and the appropriate display item (viscosity
or torque) will be updated continuously during the event. Upon completion, the viscometer will
stop and display a screen stating that the test is complete and will also display the nal recorded
value for the viscosity in the rst case, or the time in minutes and seconds to reach the torque limit
in the second case. Pressing the UP or DOWN ARROW keys will allow additional viscometer data to
be examined. Pressing any other key (except the PRINT or ENTER/AUTORANGE key) will bring the user
back to the default (normal) viscometer display with the motor OFF. Refer to the Time Modes in
Section III.3.