Brookfield DV3T User Manual

Brookeld Engineering Labs., Inc. Page 97 Manual No. M13-167-A0415
Special Considerations
Intakingviscositymeasurementswith the DV3TRheometer, there aretwoconsiderationswhich
pertaintothelowviscositylimitofeffectivemeasurement.
1) Viscositymeasurementsshouldbeacceptedwithintheequivalent%TorqueRangefrom
10%to100%foranycombinationofspindle/speedrotation.
2) Viscositymeasurementsshouldbetakenunderlaminarowconditions,notunderturbulent
owconditions.
Therstconsiderationhastodowiththeprecisionoftheinstrument.AllDV3TRheometershave
anaccuracyof+/-1%oftherangeinuseforanystandardspindleorcone/platespindle.(Notethat
accuracyvaluesmaybehigherthan1%whenusingaccessorydeviceswiththeDV3T).Wediscourage
takingreadingsbelow10%ofrangebecausethepotentialviscosityerrorof+/-1%isarelatively
highnumbercomparedtotheinstrumentreading.
Thesecondconsiderationinvolvesthemechanicsofuidow.Allrheologicalmeasurementsof
uidowpropertiesshouldbemadeunderlaminarowconditions.Laminarowisowwherein
allparticlemovementisinlayersdirectedbytheshearingforce.Forrotationalsystems,thismeans
alluidmovementmustbecircumferential.Whentheinertialforcesontheuidbecometoogreat,
theuid can break into turbulentowwhereinthe movement of uid particlesbecomesrandom
andtheowcannotbeanalyzedwithstandardmathmodels.Thisturbulencecreatesafalselyhigh
rheometerreadingwiththedegreeofnon-linearincreaseinreadingbeingdirectlyrelatedtothedegree
ofturbulenceintheuid.
Forthefollowinggeometries,wehavefoundthatanapproximatetransitionpointtoturbulentow
occurs:
1) No.1LVSpindle: 15cPat60RPM
2) No.2LVSpindle: 100cPat200RPM
3) No.1RVSpindle: 100cPat50RPM
4) ULAdapter:   0.85cPat60RPM
5) SC4-18/13R:   1.25cPat240RPM
TurbulentconditionswillexistinthesesituationswhenevertheRPM/cPratioexceeds thevalues
listedabove.
Eect on accuracy when using accessory devices
TheBrookeldrheometerhasastatedaccuracyof+/-1%oftherangeinuse.Thisstatedaccuracy
applies when the rheometer is used in accordance with the operating instructions detailed in the
instrumentinstructionmanualandthecalibrationtestuidisusedinaccordancewiththeinstructions
providedbytheuidsupplier(includingthecriticalparametersoftemperaturecontrolandstateduid
accuracy).Brookeld’saccuracystatementof+/-1%oftherangeinuseappliestotheBrookeld
rotationalrheometerwhenusedwiththestandardspindlessuppliedwiththeinstrument,includingLV
spindles1through4(suppliedwithLVseriesrheometers),RVspindles2through7(suppliedwith
RVseriesrheometers),andHVseriesspindles2through7(suppliedwithHAseriesrheometersand
HBseriesrheometers)ina600mLlowformGrifnbeaker.
Brookeld offers a range of accessories for use with the Brookeld rheometer to accommodate
specialmeasurementcircumstances.Theseaccessories,whileofferingaddedcapabilitytotheuser,
alsocontributetoanexpandedmeasurementtolerancebeyondtheinstrumentaccuracyof+/-1%of
therangeinuse.Thisexpandedmeasurementtoleranceisafunctionofmanyparametersincluding
spindlegeometry,accessoryalignmentaccuracy,samplevolumerequirement,andsampleintroduction
techniques.  The effect of these elements on measurement tolerance must be considered when
verifyingthecalibrationofyourBrookeldrheometer.Sampletemperatureinalltestcircumstances
isveryimportant,andwillalsoaddanadditionalexpandedtolerancedependingonthetemperature
controlsystemandthecalibrationvericationtestsbeginwiththestandardrheometerspindlesas
detailedabove.Oncethecalibrationoftherheometeritselfisconrmed,theexpandedtoleranceof
themeasurementsystemmaybedeterminedusingaccessorydevices.Inmanycases,thisadditional
tolerancewillbeveryminimal,butasageneralstatement,theadditionof+/-1%oftherangeinuse
isreasonableforaccessories.

Brookfield DV3T Specifications

General

Brand	Brookfield
Model	DV3T
Category	Measuring Instruments
Language	English