Brookfield YR-1 Rheometer - Manual (Page 49)

Brookfield Engineering Labs., Inc. Page 49 Manual No. M02-215-B0412
Pressing the Enter key toggles between the spindle and speed fields.
Note: The spindle must rotate at least five (5) times before readings are taken.
12) The viscosity reading should equal the cP value on the viscosity fluid standard to within the
combined accuracies of the Rheometer and the viscosity standard fluid as discussed in the
following section (Interpretation of Calibration Test Results).
13) When the calibration check is complete, switch off the rheometer or press the ESC key if
you wish to Print Parameter RAM (see Appendix H – Fault Diagnosis and Troubleshoot-
ing).
Interpretation of Calibration Test Results:
When verifying the calibration of the YR-1 Rheometer, the instrument and viscosity standard
fluid error must be combined to calculate the total allowable error.
The YR-1 is accurate to ±2% of any full scale spindle/speed viscosity range for vane spin-
dles.
Brookfield Viscosity standard Fluids are accurate to ±1% of their stated value.
Example: Calculate the acceptable range of viscosity using the RVYR-1 Rheometer and
V-71 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 A-2
SMC = 2.62 from Table A-1
Full Scale Viscosity Range 1 * 2.62 * 10,000 = 13,100 cP
2
The viscosity is accurate to ±262 cP (which is 2% of 13,100)
2) The viscosity standard fluid is 12,257 cP. Its accuracy is ±1% of 12,257 or ±123 cP.
3) Total allowable error is 262 + 123 cP = ±385 cP.
4) Therefore, any viscosity reading between 11,872 and 12,642 cP indicates that the YR-1
Rheometer is operating correctly. Any reading outside these limits may indicate a problem.
Contact the Brookfield technical sales department or your local Brookfield dealer with test
results to determine the nature of the problem.