Brookfield DV2T Viscometer - Manual (Page 24)

Brookfield Engineering Labs., Inc. Page 24 Manual No. M13-167-B0614
Many samples must be controlled to a specific temperature for viscosity measurement.
When conditioning a sample for temperature, be sure to temperature control the
container and spindle as well as the sample.
Please see our publication, “More Solutions to Sticky Problems”, for more detail relating
to sample preparation.
III.3 Selecting a Spindle/Speed
The DV2T has the capability of measuring viscosity over an extremely wide range. For
example, the DV2TRV can measure fluids within the range of 100-40,000,000 cP. This
range is achieved through the use of several spindles over many speeds. See Appendix
B for details.
The process of selecting a spindle and speed for an unknown fluid 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.
In other words: 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 satisfactory
results between 10-100%. When this circumstance occurs, any of the spindles may be
selected.
Non-Newtonian fluid behavior can result in the measured viscosity and yield stress changing
if the spindle and/or speed is changed. See our publication, “More Solutions to Sticky
Problems”, for more details.
When viscosity data must be compared, be sure to use
the same test methodology: namely the same instrument,
spindle, speed, container, temperature and test time.
DV2TLV Viscometers are provided with a set of four spindles
and a narrow guardleg; DV2TRV Viscometers come with a set
of six spindles and a wider guardleg; DV2THA and DV2THB
Viscometers come with a set of six spindles and no guardleg.
(See Appendix G for more information on the guardleg.)
The spindles are attached to the viscometer by screwing
them onto the coupling nut on the lower shaft (see Figure
III-1). Note that the spindles have a left-hand thread. The
lower shaft should be secured and slightly lifted with one hand
while screwing the spindle to the left. The face of the spindle
nut and the matching surface on the lower shaft should be
smooth and clean to prevent eccentric rotation of the spindle.
Spindles can be identified by the number on the side of the
spindle coupling nut.
The motor should be OFF whenever
spindles are being removed or attached.
Figure III-1