Brookfield DV3T Rheometer Manuale Utente Scaricare il pdf (Pagina 48)

Brookeld Engineering Labs., Inc. Page 48 Manual No. M13-2100

IV.3 Selecting a Spindle/Speed

TheDV3Thasthecapabilityofmeasuringyieldstressoveranextremelywiderange.Forexample,

theDV3TRVcanmeasureuidswithintherangeof0.5-400Pa.Thisrangeisachievedthrough

theuseofseveralvanespindlesovermanyspeeds.SeeAppendixBfordetails.

Theprocessofselectingaspindleandspeedforanunknownuidisnormallytrialanderror. An

appropriate selection will result in measurements made between 10-100 on the instrument %

torque scale.Therearetwogeneralruleswillhelpinthetrialanderrorprocess:

1)Viscosityrangeisinverselyproportionaltothesizeofthespindle.

 2)Viscosityrangeisinverselyproportionaltotherotationalspeed.

Inotherwords:tomeasurehighyield,chooseasmallspindleand/oraslowspeed.Ifthechosen

spindle/speedresultsinareadingabove100%,thenreducethespeedorchooseasmallerspindle.

Experimentation may reveal that several spindle/speed combinations will produce satisfactory

resultsbetween10-100%.Whenthiscircumstanceoccurs,anyofthespindlesmaybeselected.

When yield data must be compared, be sure to use the same test methodology: namely the

same instrument, spindle, speed, container, temperature and test time.

VanespindlesareoptionalequipmentandarenotpartofthestandardDV3Tpackage.DV3TLV

Rheometersareprovidedwithasetoffourspindlesandanarrowguardleg;DV3TRVRheometers

comewithasetofsixspindlesandawiderguardleg;DV3THAandDV3THBRheometerscome

withasetofsixspindlesandno guardleg.(SeeAppendixFformoreinformationontheguardleg.)

Do not use the guard leg with vane spindles.

Thespindlesareattachedtotherheometerbyscrewingthemonto

thecouplingnutonthelowershaft(seeFigureIV-1).Notethatthe

spindleshavealeft-handthread.Thelowershaftshouldbesecured

andslightlyliftedwithonehandwhilescrewingthespindletothe

left.Thefaceofthespindlenutandthematchingsurfaceonthe

lowershaftshouldbesmoothandcleantopreventeccentricrotation

ofthespindle.Spindlescanbeidentiedbythenumberontheside

ofthespindlecouplingnut.

ThemotorshouldbeOFF whenever

spindlesarebeingremovedorattached.

Figure IV-1

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Brookfield DV3T Rheometer Manuale Utente Pagina 48