VSA: a new fast size analysis technique for low sample weight based on Stokes' settling velocity

Abstract

A new technique, VSA, provides a rapid, accurate, and precise method of determining the grain-size distribution of low weight samples. Its name, VSA, stands for volume size analysis. The apparatus is inexpensive and the proposed system can analyze four samples simultaneously in 85 min when used down to 0.45 μm size. The results are provided in sedimentation diameters. A set of equations, which discretely define the increasing volume of a homogeneous sediment sample settling in an enclosed volume of water, is solved to adequately approximate the continuous distribution. The final distribution is in terms of weight percent when bulk densities of discrete settled volumes are calculated. This additional calculation has only a marginal effect on the grain-size distribution of samples having means greater than 3 μm.VSA was compared with the pipette method and found to produce "statistically identical" size distributions.