On the measurement of the size characteristics of powders by photo-extinction methods. I. Theoretical considerations

✍ Scribed by Rose, H. E. ;Lloyd, H. B.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1946
• Weight: 670 KB
• Volume: 65
• Category: Article
• ISSN: 0368-4075
• DOI: 10.1002/jctb.5000650204

✦ Synopsis

Abstract

In recent years a considerable number of apparatus for the determination of the size characteristics of fine powders has been devised but, on the grounds of general convenience, the email sample of powder necessary for a teat and the high accuracy with which the fundamental measurements may be carried out, the typos of apparatus involving photo‐extinction methods appear to be without equal.

Unfortunately the method is subject to a considerable number of errors, some arising from the motion of the particles in the necessary suspension fluid and others from the fact that the mathematical laws of transmission of light through a suspension of particles, upon which the calculations are based, are only partially obeyed in practice so, although the measurements may be made with high precision, considerable errors may arise unless due allowance is made for the effects of these deviations.

In the present work the errors arising from the second only of the sources enumerated above will be considered, since there appears to have been no systematic investigation into the errors arising from this cause.