Brookfield DV-I Viscometer - Manual (Page 37)

Brookfield Engineering Laboratories, Inc. Page 37 Manual No. M/92-021-O604
4) With the viscometer stopped, remove the sample cup and place the viscosity standard fluid
into the cup.
5) Allow sufficient time for temperature to reach equilibrium, and connect the sample cup
to the Viscometer.
6) Measure the viscosity and record the Viscometer reading in both % torque and centipoise.
NOTE: The spindle must rotate at least five (5) times before a viscosity reading is taken.
Interpretation of Calibration Test Results:
When verifying the calibration of the DV-I+, the instrument and viscosity standard fluid error
must be combined to calculate the total allowable error.
The DV-I+ 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-I+ 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
viscometer 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 construc-
tion 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 mecha-
nism.