Brookfield Engineering Laboratories, Inc.
Page 98
Manual No. M98-211-E0912
A.4 VERIFYING CALIBRATION
1. Determine the appropriate sample volume.
C o n e
S a m p l e Vo l u m e
Pa r t N o .
C P A - 4 0
0 . 5 m l
C P A - 4 1
2 . 0 m l
C P A - 4 2
1 . 0 m l
C P A - 5 1
0 . 5 m l
C P A - 5 2
0 . 5 m l
Ta b l e A 6
Table A-1
Refer to Table A-1 to determine the correct
sample volume required for the spindle to be
utilized.
2. Select a Brookfield Viscosity Standard fluid
that will give viscosity readings between
10% and 100% of full scale range. Refer
to
Appendix B
for viscosity ranges of cone
spindles; ranges listed apply to CPA cones.
Do not use a silicone viscosity standard fluid with a viscosity value greater than 5000 cP with a
Cone/Plate. Brookfield offers a complete range of mineral oil viscosity standards suitable for
use with Cone/Plates for viscosities above 5,000 cP or shear rates above 500 sec
-1
; see Table E-2
in Appendix E for a list of available fluids.
It is best to use a viscosity standard fluid that will be close to the maximum viscosity for a given
cone spindle/speed combination.
Example:
LVDV-III Ultra Viscometer, Cone Spindle CPE-42, Brookfield Silicone
Viscosity Standard having a viscosity of 9.7 cP at 25°C
At 60 RPM, the full scale viscosity range is 10.0 cP. Thus, the Viscometer reading should be
97% torque and 9.7 cP viscosity ± 0.197 cP. The allowable error (±0.197 cP) is a combination
of Viscometer accuracy and fluid tolerance (refer to
Interpretation of Calibration Test Results
at the end of Appendix E).
3. Set the gap as described in Section A.3.
4. With the motor off, remove the sample cup and place the viscosity standard fluid into the cup.
5. Attach the sample cup to the Viscometer and allow sufficient time for the sample, cup and cone
to reach temperature equilibrium.
6. Turn the motor on. Set the desired speed(s). Measure the viscosity and record the reading in
both % torque and centipoise (cP).
Note:
The cone spindle must rotate at least five (5) times before a viscosity
reading is taken.
7. Verify that the viscosity reading is within the allowable 1% deviation, as explained earlier, for
the specific viscosity standard fluid(s) that you are using.
*
The CPE designation on the cone spindle indicates use with Electronic Gap Setting Cone/Plate
Viscometers/Rheometers
only
.
