Brookeld Engineering Labs., Inc. Page 99 Manual No. M13-167-A0415
Rheometer Related Variables
Mostuidviscositiesarefoundtobenon-Newtonian.TheyaredependentonShearRate,timeoftestand
thespindlegeometryconditions.ThespecicationsoftheRheometerspindleandchambergeometry
willaffecttheviscosityreadings.Ifonereadingistakenat2.5RPM,andasecondat50RPM,the
twocPvaluesproducedwillbedifferentbecausethereadingsweremadeatdifferentshearrates.The
fasterthespindlespeed,thehighertheshearrate.
Theshearrateofagivenmeasurementisdeterminedby:therotationalspeedofthespindle,thesize
andshapeofthespindle,thesizeandshapeofthecontainerusedandthereforethedistancebetween
thecontainerwallandthespindlesurface.
Arepeatableviscositytestshouldcontrolorspecifythefollowing:
1) Testtemperature
2) Samplecontainersize(orspindle/chambergeometry)
3) Samplevolume
4) Rheometermodel
5) Spindleused
6) Whetherornottoattachtheguardleg
7) Testspeedorspeeds(ortheshearrate)
8) Lengthoftimeornumberofspindlerevolutionstorecordviscosity
9) Howthesamplewaspreparedand/orloadedintothecontainer