Thermo Scientific HAAKE RotoVisco 1 Instruction Manual page 104

Sensor Systems
1. Cone/plate gap error
The measuring cones are equipped with a truncated tip
which corresponds to a fictive gap. If this gap is not observed
measuring errors will occur, since the assumptions made
when determining the calculation factors no longer hold true.
a
x
If the "ideal" gap distance "a" is increased, the viscosity cal-
culation deviates as detailed below:
Measuring =
uncertainty
2. Cone/plate reduced effective radius error
If a cone/plate sensor system is insufficiently filled or the gap
empties itself during a measurement, significant measure-
ment errors can result. This condition of insufficient filling can
be referred to as a reduced effective radius error and is char-
acterized by a reduction in the effective radius.
R = R R
eff
The measurement error can be estimated using the follow-
ing equation:
viscosity measuring error = 1 −
102
R
x  (  0.0174) / R / 1000
 = cone angle
R = cone radius in (mm)
R = plate radius
R
= effective radius
eff
R

R
reduced effective radius
= R -- R
eff
R
(R − ΔR)
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