Brookfield PFT Powder Flow Tester Operating Instructions Manual page 60

The bulk density is commonly displayed as a bulk density curve (Figure A-9). Generally a free
flowing material will be incompressible and only show a small increase in density with stress.
A very cohesive, poorly flowing, bulk solid by comparison will show a large increase in bulk
density with increasing stress.
The fill bulk density, when the powder is just poured into a container
ρ
fill
ρ The bulk density after the material is poured and compacted to high stress.
comp
Summary
To summarize, the Brookfield Powder Flow Tester offers four standard tests,
1. Flow function test - Measures internal strength, flow function, internal friction angle
and bulk density - used for characterizing the flow strength and arching/ rat-holing
potential of powders.
2. Time consolidated flow function test – Same as above but following static storage for
a user defined time period.
3. Wall friction test - Measures friction between the powder and a given wall surface and
the bulk density – used for assessing mass-flow hopper half angles and gravity flow
chute angles.
4. Bulk density test – Measures bulk density curve of the powder.
Note: To undertake a full silo design requires the user to run and combine the results of
tests 1, 2 and 3.
AMETEK Brookfield
Incompressible material
Compressible material
Full bulk density (
Major Principal Consolidation Stress σ
Figure A-9: Bulk density curve
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)
ρ
fill
1
Manual No. M09-1200-F1016