Central drive circular scraper bridge
For primary and secondary setting, utilizing the force of gravity for the removal of solids
It consists of a rotation unit with a bottom scraper system having two blade holder arms, a central deflector cylinder which defines the mixing and flocculation compartment and a peripherical weir. The sludge scraper blades remove the sludge precipitated to the sloping bottom of the tank and gathers it in a central ditch wherefrom it is then sucked. The clarified wa-ter is removed by means of the weir. The scraper and any moving parts of the bridge are supported and moved only through the central shaft.
This way, the sedimentation tank volume, free from any parts in motion allows, for example, the installation of lamellar packs in its inside and it avoids the maintenance on the clarifier edge required if the bridges is peripherical driven type, in correspondence of the traction trolleys.
The protection against overloads is carried out by an adjustable dynamometric torque limit switch complete with alarm sig-nalling device is required.