Drum thickener for sludge treatment
Passavant Geiger

Stirring and scraping mechanisms are installed in sludge thickener tanks to reduce the water content of sludges and to continously remove the still fluid and pumpable sludge to the central sludge sump.

Function
The raw, mixed or digested sludge is fed through a central influent cylinder mounted to the thickener mechanism into the thickener tank.
The thickening process is intensified with the application of vertically mounted stirring members. By means of an echelon type scraper blade assembly the thickened sludge on the tank bottom is removed to a center hopper from where it is drawn off by hydrostatic pressure or pumped off to further treatment facilities. Depending upon the mode of operation, the supernatant is drawn-off from the surface continously or discontinously into a discharge trough via overflow weirs or via level adjustable or floating supernatant discharge devices.

Design
A support bridge (mostly a concrete bridge, alternatively a steel bridge) is spanning the thickener tank. The thickener unit is driven by a central drive with a geared slewing ring ball.
For overload protection an electronic system measuring the true power output of the electric motor is included in the supply.

Types
sizes: Ø 5 - 30 m,
types: central drives 3Z - 50Z = torques 3 - 50 kNm
blade load class: the drives are designed for a solids content of 8% acc. DIN 19569 part 2 blade loading class 3