SYMPOSIA PAPER Published: 01 January 1959

A Photoelectric Sedimentation Method for Particle Size Determination in the Subsieve Range


The method consists essentially of measuring the light absorbed by a suspension of the particles in a liquid medium; increments of light absorption are measured as the particles settle in the medium. A photoelectric cell is used to measure the light absorption.

The apparatus is simple and comprises a stable light system, a cell (for containing the suspension), a photoelectric cell, and a microammeter.

Calculations are based on Stokes' law, with modifications to compensate for variations with very fine particles. Comparison with other methods shows good agreement.

While not absolute, the method is reasonably accurate and reproducible; it has the distinct advantage of speed and simplicity and gives a complete size distribution. The elapsed time required for a determination is approximately 1hr.

A wide variety of materials has been successfully analyzed by this method.

Author Information

Harner, HR
The Eagle-Picher Co., Joplin, Mo
Musgrave, JR
The Eagle-Picher Co., Joplin, Mo
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Developed by Committee: E29
Pages: 172–179
DOI: 10.1520/STP39297S
ISBN-EB: 978-0-8031-5662-3
ISBN-13: 978-0-8031-5661-6