The Grit Screw Classifier is a grit conveying and dewatering unit which typically receives a grit slurry from a Vortex Grit Separator, an Aerated Grit Chamber, or a Grit Collector.    The Grit Screw Classifier settling tank is designed to effectively separate and settle the grit from the water.  The shafted screw is supported by upper and lower bearings so that the screw never contacts the trough.  Grit is transported by the screw along a bed of grit which builds up between the rotating screw and the tank/trough.  As the grit is conveyed out of the settling tank it is lightly washed, dewatered, and discharged into a suitable receptacle for disposal while the water and organics flow gently over a weir and exits the classifier for further treatment.

The Grit Screw Classifiers are often provided with a hydro cyclone grit separator(s) to meet larger flow requirements (250+ gpm).  Using hydraulic forces (no moving parts), the hydro cyclone separator concentrates the grit and reduces the amount of water that is delivered to the classifier.  The overflow from the cyclone separator is returned to the process stream for further treatment.  The cyclone separator is provided with gum rubber liners.

BENEFITS

• Both standard size models and custom designed units are available. 

• Common materials of construction available: carbon steel, Type 304 SS, or Type 316 SS

• Standard carbon steel screw provided with heavy-duty shaft, welded flights, and durable UHMW-PE wear shoes.    Optional Ni-Hard wear shoes (12”, 16”, 18”, and 24” dia. screw sizes) or a welded hardened screw facing are also available.

• Submerged lower bearing assembly provided with a grey cast-iron housing, dual ball- bearing races, and a rugged mechanical seal for long life.  Maintenance of the oil lubricated lower bearing assembly is limited to a single yearly inspection. 

• Polycarbonate tank/trough covers provides safety to operators while permitting visual inspection of the unit during operation.