TT100 In-Line Viscometer Installation, Operation, Maintenance and Service Instructions
P/N M/97-520 C-1
Appendix C - Viscosity Range Change
Introduction
The model TT100 viscometer operates under defined shear conditions.
As a single speed instrument, the viscometer measures viscosity at one
specific shear rate as determined by the speed of rotation and the internal
measuring geometry.
Depending on the application, the model TT100 viscometer can be
redesigned, with minimal effort, to change the measured viscosity range
and/or the shear conditions. With the design of this viscometer, the
viscosity range is inversely proportional to speed, and shear rate.
With the limited single-point viscosity measurement, on a bench-top
(laboratory) viscometer, little is known about the viscosity of the process
fluid while it flows under different conditions in the process stream.
Therefore, we normally provide some built-in flexibility in the measured
viscosity range and shear rate to allow changes to be made in instrument
ranging after initial shipment.
Changing Range or Shear Rate
Reasons for changing the existing viscosity range:
• Better accuracy; accuracy is defined as + 1% of full scale range.
Accuracy improves with a finer viscosity range.
• Formulation change in the process.
• Over-ranging, requires broader viscosity range.
Reasons for changing the existing shear rate:
• Measure viscosity at a different part of the rheogram curve.
• Correlate/track with bench-top viscosity measurements in the
laboratory.
In order to change both the shear rate and viscosity measurement range, the
stationary cylinder (stator), and/or the gear box (speed of rotation) must be
replaced.
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