Brookfield DV2T - Page 77

Brookeld Engineering Labs., Inc. Page 77 Manual No. M13-167
BrookeldViscosityStandardsFluidsareaccurateto(+/-)1%oftheirstatedvalue.
Example:
 CalculatetheacceptablerangeofviscosityusingDV2TRVwithRV-3Spindleat
2RPM;Brookeld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 D-2
SMC=10fromTable D-1
Full Scale Viscosity Range
1
*
10
*
10,000
=
50,000 cP
2
 Theviscosityisaccurateto(+/-)500cP(whichis1%of50,000)
2) Theviscositystandarduid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BrookeldtechnicalsalesdepartmentoryourlocalBrookelddealer/distributor
withtestresultstodeterminethenatureoftheproblem.
Example:
Calculate the acceptable accuracy for viscosity measurement using DV2TLV
withSC4-21spindleinSmallSampleAdapterat6,12,and30RPM.Brookeld
viscositystandarduid100cPshasanactualvalueof101.5cPat25ºC.
1) Calculate thefullscale viscosity range eitherbyusing the SpindleRangeCoefcientin
AppendixBofMoreSolutionstoStickyProblemsorbyusingtheAutoRangebuttononyour
viscometer.
 TheSpindleRangeCoefcientforthe21spindleonanLVTorqueinstrumentis4,688.
 At6RPM,theFullScaleRange(FSR)viscosityis781cP.Allow+/-1%fortheviscometer
and+/-1%fortheSmallSampleAdapter.Totalallowableaccuracyis:
  +/-2%x781cP=+/-15.6cP
 Asimilarcalculationat12RPMgivesFSR=391cP:+/-2%x391cP=+/-7.8cP
 Asimilarcalculationat30RPMgivesFSR=156cP:+/-2%x156cP=+/-3.1cP
2) TheViscosityStandardFluidis101.5cP.Itsaccuracyis:
  +/-1%x101.5cP=+/-1.015cPorroughly+/-1.0cPforfurthercalculations.