Brookfield Engineering Labs., Inc.
Page 47
Manual No. M13-167-A0415
IV. MAKING YIELD MEASUREMENTS
IV.1 Quick Start
The DV3T Rheometer uses the same methodology for yield measurements as the Brookfield YR-1
and DV-III Ultra Rheometers. If you have experience with other Brookfield equipment, this section
will give you quick steps for making a yield measurement. If you have not used a Brookfield
Rheometer before, skip this section and go to Section IV.2 for a detailed description.
A) Assemble and level the DV3T Rheometer (Section I.4).
B) Turn power on.
C) Autozero the rheometer (Section II.2).
D) The DV3T will display the Configure Viscosity Test Screen. Press the Home Icon in
the Navigation Bar. From the Home Menu, select Configure Yield Test.
E) Select: Spindle, Immersion Mark, and Run Speed.
F) Attach the vane spindle to the DV3T.
NOTE: Left-hand thread.
If equipped with EZ-Lock, use the appropriate procedure
to connect the spindle (see Section III.3). Immerse the spindle gently into the test
sample by lowering the DV3T on the Model G laboratory stand.
G) Press the Run button. The screen will change to the Running Yield Test Screen.
H) When the Yield Test is complete, the DV3T will present the Yield Test Complete
screen. Record the Stress (yield stress), Torque, and Temperature.
I)
To run another test, press Configure Test. To return to the Home Menu, press the
Home Icon.
IV.2 Preparations for Making Measurements
A) RHEOMETER: The DV3T should be turned on, leveled and autozeroed. The level is adjusted
using the two feet on the bottom of the base and confirmed using the bubble level on the front
of the head. Adjust the feet until the bubble is inside the center target. Set the level prior to
autozero and check the level prior to each measurement.
The proper level is essential for correct operation of the DV3T.
B) Sample: The measured yield value is very dependent on how the sample is handled prior to the
measurement. The sample should be disturbed as little as possible prior to inserting the vane
spindle. Brookfield recommends testing the sample in the container in which it is provided when
possible. If it is necessary to transfer the sample to a new container, then it is recommended to
include a pre-shear and/or wait time in the Yield Test. This pre-shear and wait-time will provide
a common history to each sample to aid in sample to sample comparison.
Brookfield recommends the use of vane spindles for measuring yield value. The vane spindle
provides a unique geometry that minimizes disturbance of the sample during spindle insertion.
Many samples must be controlled to a specific temperature for yield measurement. When
conditioning a sample for temperature, be sure to temperature control the container and spindle
as well as the sample.
