Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...
Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...
Strona 2_redak - Instytut Agrofizyki im. Bohdana DobrzaÅskiego ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
98<br />
obtained the max<strong>im</strong>um deviation of the strength 1 c not higher than ± 0,13 kPa, not<br />
dependent on the level of consolidation pressure. These authors have reported<br />
good repeatability of results with deviation not higher than 5%. According to the<br />
authors, the reproducibility of the tester, together with operator independence and<br />
fairly rapid test procedure make the equipment a suitable tool for quality control<br />
of powders. Accuracy of the method allows for flow property deviations from<br />
batch to batch in batch production operations. The equipment may be also used<br />
for investigations of the compaction properties of slightly compacted samples,<br />
determination of the modulus of elasticity, or examinations of stress relaxation<br />
and creep phenomena of powders.<br />
3LVWRQ<br />
0ROG<br />
(ODVWLF<br />
PHPEUDQH<br />
6DPSOH<br />
%DVH<br />
SODWH<br />
D8QLD[LDOFRPSUHVVLRQ<br />
E)DLOXUH<br />
Fig. 13.4. POSTEC uniaxial tester [102]<br />
13.2. Carr Indices<br />
Chemical industry and, particularly, pharmaceutical industry need characterization<br />
of fine powders. Flowability determines operations of transport, mixing,<br />
dosing, storage granulation or forming tablets. Carr Indices are willingly used by<br />
practitioners of those industries, and were standardized by the American Society for<br />
Testing Materials [7]. The method can be applied to free flowing and moderately<br />
cohesive powders and granular materials up to 2 mm in size. Materials must be able<br />
to pour through a 7.0 ± 1.0 mm diameter funnel outlet when in aerated state. The<br />
method consists of eight measurements and two calculations to provide ten tests for<br />
Carr Indices. These ten tests are as follows: