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.