Shafted Grit Screw Classifier
Shafted Grit Screw Classifier Overview
The shafted grit screw classifier is a grit conveying and dewatering unit that typically receives grit slurry from a vortex grit separator, an aerated grit chamber, or a grit collector. The shafted 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. The water and organics flow gently over a weir and exit the classifier for further treatment.
Shafted grit screw classifiers are often provided with a hydrocyclone grit separator to meet larger flow requirements (250+ gpm or 1363+ m3/d). Using hydraulic forces (no moving parts), the hydrocyclone 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.