The Flottweg Impeller
Normally, the clarified liquid runs out of a decanter without pressure over weir plates. As an alternative to the weir plates, operators of systems transport the clarified liquid away using an impeller. This means the clarified liquid runs out in a closed system under pressure. It is a prerequisite for correct function that there must not be any solid phases, etc. in the centrate which could cause blockage of the impeller.
The adjustable impeller
A further development of the impeller is the adjustable impeller. In this variant, an adjustment mechanism alters the position of the impeller. This means the liquid flows out at different diameters (simply by moving a lever). Furthermore, adjusting the impeller optimises the separating performance, because it is possible to respond quickly to changed product properties in the feed.
Basically, it is possible to say:
- Small diameter of the impeller ► deep pond
- Large diameter of the impeller ► shallow pond
The diameter of the selected weir discs depends on the type of application or requirements. The set diameters can be read off easily using a scale.
The adjustable impeller and its advantages
- The variable impeller can be adjusted during ongoing operation
- Optimum adaptation to changed conditions (product property in the feed)
- Perfect separating properties are achieved, for an optimum product result
- Exact and variable setting of the pond depth is possible (by changing the weir disc diameter)
- Automation is possible
- Outflow of liquid under pressure replaces a pump that would normally be required
- Scale can be read off easily and without problems