Brookfield DV2T Viscometer - Manual (Page 25)

Brookfield Engineering Labs., Inc. Page 25 Manual No. M13-167-B0614
If your instrument has the EZ-Lock system, the spindles are
attached as follows:
With one hand hold the spindle, while gently raising the spring-
loaded outer sleeve to its highest position with the other hand,
as shown in Figure III-2. Insert the EZ-Lock Spindle Coupling
so that the bottom of the coupling is flush with the bottom of
the shaft, and lower the sleeve. The sleeve should easily slide
back down to hold the spindle/coupling assembly in place for
use. [Spindles can be identified by entry code; look for the
number on the side of the EZ-Lock spindle coupling.]
The motor should be OFF whenever
spindles are being removed or attached.
Note
: Keep the EZ-Lock Spindle Coupling and
outer sleeve as clean as possible and free
from debris that could become lodged
inside the adapter.
III.4 Multiple Data Points
The majority of viscosity and yield stress measurements are made at the quality control
level and often consist of a single data point. The test is conducted with one spindle at one
speed. The data point is a useful bench mark for the go/no-go decision in a production
setting. The DV2T can be used for single point measurement.
Many fluids exhibit a characteristic change in viscosity and yield stress with a change in
applied force. This non-Newtonian flow behavior is commonly seen in paints, coatings and
food products as a decrease in viscosity as shear rate increases or an increase in yield
stress as a rotational speed increases. This behavior cannot be detected or evaluated
with the single point measurement.
Non-Newtonian flow is analyzed through the collection of viscosity data over a range of
shear rates and the generation of a graph of viscosity versus shear rate (a rheogram).
This information will allow for a more complete characterization of a fluid and may help in
formulation and production of a product. The DV2T is capable of collecting multiple data
points for comprehensive analysis of flow behavior when using test programs created with
PG Flash Software (see Section V).
More information on flow behavior, shear rate and rheograms is available in our publication,
“More Solutions to Sticky Problems”.
III.5 Selecting Data Collection
The DV2T Viscometer offers several options for data collection. The Data Collection setting
is shown in Configure Viscosity Test directly under the Temperature display. The factory
setting is Single Point (see Figure III-3). Pressing the blue arrow, in this field, will present
the Data Collection screen (see Figure III-4).
Figure III-2