ABSTRACT
Disk stack separators represent an industrial standard for mechanical separation within a large range of applications. To date, the prediction of separation efficiencies for disk stack separators is largely based on the concept of the equivalent clarification area, namely the Σ-Theory. This theory is based on various simplifying assumptions which lead to inconsistencies with experimental results. The separation process inside the top disk gap of a disk stack centrifuge with a transparent bowl top is visualized using a high-speed camera. The influence of disk geometry parameters on the flow and particle separation is analyzed by image processing and the unused clarification areas are determined. The analysis shows that the ratio of unused clarification area is significant.
Abbreviations: GEA: GEA Group AG; PMSQ: Polymethyl silsesquioxane beads; PVAc: Poly(vinyl acetate) beads; rpm: Revolutions per minute; 3D: Three-dimensional
KEYWORDS:
Novelty statement
The Σ-Theory theory, which is used for the prediction of separation efficiency for disk stack separators, is based on various simplifying assumptions which lead to inconsistencies with experimental results. One of the reasons may be an inefficient use of the clarification area, which can be influenced by holes in the disks. Therefore, experiments are conducted with a slightly modified disk-stack centrifuge. The bowl top is made of transparent acrylic glass, the remaining model equals an industrial used separator. The separation of particles was observed by a high-speed camera and the images were analyzed by the use of image processing software. The full separation process in an industrial disk stack separator and the usage of the clarification area has not been recorded and analyzed before.
List of symbols
Scalar Quantities
Table
Dimensionless Numbers
Table
Indices
Table