Check whether settling changes the concentration within the measured region before comparing a long rheology run with an original bulk formulation.
Identify the Deformation and Model
NETZSCH explains that sedimentation can alter a suspension during viscosity measurement and discusses a dispersion-paddle approach. Its relative measurement interpretation must be retained rather than treating every geometry as an absolute-viscosity method. Primary reference: sedimentation during rheology.
Review a Hypothetical Comparison
Consider an invented vessel divided into two equal-volume regions that were initially both at particle volume fraction 0.20. Redistribution leaves one at 0.10 and the other at 0.30, while the combined average remains 0.20. A sensor interrogating only one region no longer sees the original concentration even though the inventory average is unchanged.
Keep the Evidence with the Decision
Mark the region interrogated by the geometry, sampling time and evidence of particle redistribution. Keep actual particle and liquid properties with any settling estimate. Distinguish material remixing from a measurement correction: changing the flow field may change the sample history as well as its distribution. Ask which quantity the selected geometry can legitimately report.
The equal-region arithmetic assumes unchanged total volume and particle inventory. It does not predict settling speed or establish that the quoted fractions apply to a particular product. No paddle, geometry constant or HM dispersion performance is specified. The decision is whether the reported viscosity belongs to a representative, stable composition or to an evolving local region that needs its own interpretation.
Can particle sedimentation alter the local sample during the test interval?
This blank worksheet is for your own project. It contains no H M machine trial result.
| Review field | Reference or result | Responsible person |
|---|---|---|
| Interrogated region and elapsed time | To complete | To complete |
| Particle/liquid and redistribution evidence | To complete | To complete |
| Local versus bulk concentration | To complete | To complete |
| Geometry quantity and calibration boundary | To complete | To complete |
Customer Questions
Does unchanged bulk concentration prove an unchanged local sample?
No. Redistribution can change the measured region.
Do the fractions determine settling speed?
No. Transport properties and conditions are needed.
Is every paddle output absolute viscosity?
No. Preserve the method’s stated interpretation.
Primary References
These references support the technical principles discussed in this guide. The worked examples and review questions are educational.
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