Solids are deposited on the bowl inner diameter under the influence of centrifugal force. In this process, the scroll is the transport tool in a decanter. It rotates with a differential speed (in relation to the bowl) and transports the settled solids towards the conically narrowing end of the bowl.

The Flottweg decanter scroll – additional functions

Furthermore, the differential speed defines how long the solid spends in the bowl. Consequently, the differential speed has a decisive effect on the total dry solids that can be achieved, and is optimally adapted according to the separation task. Past projects and processes have shown that there is no „standard scroll“. As a result, Flottweg decanter scrolls are available that have been specifically developed and produced for customers‘ particular requirements and processes.

The decanter scroll – design

The scroll pitch is the distance between the scroll blades of a helical turn, i.e. the advance movement performed by the scroll during one rotation. This means the scroll pitch is significant in terms of the transport performance of the scroll. Another design feature of the scroll is the loading point at which the medium to be separated enters the decanter bowl. This differs according to the application and requirement.

The Flottweg decanter scroll – number of turns

The transport performance can be increased when multi-turn scrolls are used. Single and two-turn scrolls are normal.

By exchanging or modifying the scroll, it is possible to adapt Flottweg decanters to the modified requirements when the product is changed. This means it is also possible to select between scrolls with different pitches or single and multi-turn scrolls.

The decanter scroll – summary

Decades of experience show that decanters work optimally when the decanter scroll is correctly and exactly adapted to the separation task or application. The advantage that Flottweg offers its customers concerns having very many different scroll types to choose from.