| Popis: |
Glidants have often been selected by subjective or indirect methods such as measurement of the angle of repose. As a result, several materials have been empirically classified as glidants. The recording powder flowometer described in Part I of this series was utilized to evaluate various glidants. A comparison was made between the results obtained with this instrument and those by measurement of the angle of repose. The commonly used glidants, fumed silicon dioxide, magnesium stearate, starch, and talc were studied in combination with selected materials. Many of the more widely used glidants actually decreased the flow rate. Glidants which lowered the angle of repose did not necessarily increase the flow rate and marked changes in flow rate were not always detectable by angle of repose measurement. In addition, a comparison of the angle of repose and the flow rate of various commonly used raw materials indicated that the angle of repose was not a reliable method for evaluating the flow of these materials. |
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