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The flow properties of these materials are not easily
measured using traditional coaxial cylinder or cone
& plate equipment. Vane spindle geometry provides a
solution. The vane spindle is lowered into the test
sample with minimal disruption. The test is easily run
in the sample's original container.
There are two significant Test Methods easily
accomplished by the Soft Solids Tester:
- 1. Constant Rate Yield Test
-
- For Products
Like: Stiff pastes, slurries, set gels,
waxes
- Properties
Measured:Yield Stress, Yield Strain,
Modulus
- Test
Description:This is a Constant Shear Rate
Test. The vane is rotated at a constant low
rotational rate and the Stress (torque) is
measured against Time, Rotational Angle or
Strain.
- Example Method
for Mayonnaise:Constant Rotation at 0.2
rpm, 60 data points are taken in 60 seconds
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Typical Results Plot |
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- 2. The Creep/Recovery Test
-
- For Products
Like:Gels, lumpy products like custard,
gravy, sauces and jams
- Properties
Measured:Instantaneous Strain, Viscous
Creep, Elastic Recovery, Permanent Flow
- Test
Description:This is a Constant Stress
Test. The Stress (torque) is applied to the
sample for a fixed time period, usually from one
to five minutes. The degree of sample movement
is recorded against time as Angular
Displacement, Strain or Compliance. The Stress
is removed and the Elastic Recovery and
Permanent Flow is determined.
- Example Method
for Fruit Preserves:Constant Stress of
1,250 Pa is applied over 120 seconds and 60 data
points are taken. The stress is then removed and
60 data points are taken for another 120
seconds.
| Typical Results Plot |
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