Brookfield DV-II+ Programmable Viscometer - Manual (Page 58)

Brookfield Engineering Labs., Inc. Page 58 Manual No. M/97-164-F1102
Interpretation of Calibration Test Results:
When verifying the calibration of the DV-II+, the instrument and viscosity standard fluid error must be
combined to calculate the total allowable error.
The DV-II+ 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-II+ 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 Viscom-
eter is operating correctly. Any reading outside these limits may indicate a Viscometer problem.
Contact the Brookfield technical sales department or your local Brookfield dealer/distributor
with test results to determine the nature of the problem.
The Brookfield Guardleg
The guard leg was originally designed to protect the spindle during use. The first applications of the
Brookfield Viscometer included hand held operation while measuring fluids in a 55-gallon drum. It is
clear that under those conditions the potential for damage to the spindle was great. Original construction
included a sleeve that protected the spindle from side impact. Early RV guard legs attached to the dial
housing and LV guard legs attached to the bottom of the pivot cup with a twist and lock mechanism.
The current guard leg is a band of metal in the shape of the letter U with a bracket at the top that attaches
to the pivot cup of a Brookfield Viscometer/Rheometer. Because it must attach to the pivot cup, the guard
leg cannot be used with a Cone/Plate instrument. A guard leg is supplied with all LV and RV series
instruments, but not with the HA or HB series. It’s shape (shown in Figure 1) is designed to
accommodate the spindles of the appropriate spindle set; therefore, the RV guard leg is wider than the
LV due to the large diameter of the RV #1 spindle. They are not interchangeable.