Owner manual

Brookfield Engineering Laboratories, Inc. Page 71 Manual No. M/98-211-A0701
4) With the viscometer stopped, remove the sample cup and place the viscosity standard fluid into
the cup, waiting 10 minutes for temperature equilibrium.
5) Connect the sample cup to the Rheometer. Allow sufficient time for temperature to reach
equilibrium. Typically 15 minutes is the maximum time that you must wait. Less time is required
if spindle and cup are already at test temperature.
6) Measure the viscosity and record the Rheometer reading in both % torque and centipoise (cP).
Notes: 1) The spindle must rotate at least five (5) times before a viscosity reading is taken.
2) The use of Brookfield Viscosity Standard fluids in the range of 5 cP to 5000 cP
is recommended for cone/plate instruments. Please contact Brookfield Engineer-
ing Laboratories or an authorized dealer if your calibration procedure requires
more viscous standards.
3) Select a 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. Do not use a silicone viscosity standard fluid with a viscosity value
greater than 5000 cP with a Cone/Plate Viscometer. Brookfield offers a complete
range of mineral oil viscosity standards suitable for use with Cone/Plate Viscom-
eters as shown in Table E2. Consult with Brookfield or an authorized dealer to
determine which fluid is appropriate.
Interpretation of Calibration Test Results:
When verifying the calibration of the DV-III+, the instrument and viscosity standard fluid error must
be combined to calculate the total allowable error.
The DV-III+ is accurate to (
+/-) 1% of any full scale spindle/speed viscosity range.
Brookfield Viscosity Standards Fluids are accurate to (+/-) 1% of their stated value.
Example: Calculate the acceptable range of viscosity using RVDV-III with RV-3 Spindle at
2 RPM; Brookfield Standard Fluid 12,500 with a viscosity of 12,257 cP at 25°C:
1) Calculate full scale viscosity range using the equation:
Full Scale Viscosity Range [cP] = TK
*
SMC
*
10,000
RPM
Where:
TK = 1.0 from Table D2
SMC = 10 from Table D1
Full Scale Viscosity Range = 50,000 cP
1
*
10
*
10,000
2
The viscosity is accurate to (+/-) 500 cP (which is 1% of 50,000)
2) The viscosity standard fluid is 12,257 cP. Its accuracy is (+/-)1% of 12,257 or
(+/-)122.57 cP.
3) Total allowable error is (122.57 + 500) cP = (+/-) 622.57 cP.
4) Therefore, any viscosity reading between 11,634.4 and 12,879.6 cP indicates that the Rheometer
is operating correctly. Any reading outside these limits may indicate a Rheometer problem.
Contact the Brookfield technical sales department or your local Brookfield dealer/distributor
with test results to determine the nature of the problem.