Brookfield DV3T - Page 99

Brookeld Engineering Labs., Inc. Page 99 Manual No. M13-167-A0415
Rheometer Related Variables
Mostuidviscositiesarefoundtobenon-Newtonian.TheyaredependentonShearRate,timeoftestand
thespindlegeometryconditions.ThespecicationsoftheRheometerspindleandchambergeometry
willaffecttheviscosityreadings.Ifonereadingistakenat2.5RPM,andasecondat50RPM,the
twocPvaluesproducedwillbedifferentbecausethereadingsweremadeatdifferentshearrates.The
fasterthespindlespeed,thehighertheshearrate.
Theshearrateofagivenmeasurementisdeterminedby:therotationalspeedofthespindle,thesize
andshapeofthespindle,thesizeandshapeofthecontainerusedandthereforethedistancebetween
thecontainerwallandthespindlesurface.
Arepeatableviscositytestshouldcontrolorspecifythefollowing:
 1) Testtemperature
 2) Samplecontainersize(orspindle/chambergeometry)
 3) Samplevolume
 4) Rheometermodel
 5) Spindleused
 6) Whetherornottoattachtheguardleg
 7) Testspeedorspeeds(ortheshearrate)
 8) Lengthoftimeornumberofspindlerevolutionstorecordviscosity
 9) Howthesamplewaspreparedand/orloadedintothecontainer