Investigation about data reduction and sedimentation distance of sedimentation balance method

The Sedimentation balance type particle size analyzer is improved. The slur ry supply device was automated and the height of peripheral wall of the det ective tray was raised. As a result we can acquire data of the sedimentatio n mass change accurately. Moreover, the ratio of measured total sedimentati on mass to the theoretical total sedimentation mass was kept constant rangi ng from 1.00 to 1.02 independent of particle size. By the above improvement , we can develop a more precious sedimentation balance. Twomey's non-linear iteration method was applied to retrieve a particle siz e distribution from the sedimentation curve measured with a sedimentation b alance method. It is found that the non-linear iteration method can calcula te size distributions accurately. Furthermore, the influence of the thickness at the base of the detective tr ay on the sedimentation distance was also investigated. As a result, it is clarified that the change in detected mass did not depend on thickness at t he base of the tray. Therefore, it is concluded that the sedimentation dist ance in the sedimentation balance method should be defined as the distance between the lower surface of the base of the tray and suspension surface.