Screw filter

FC

CATEGORY SEWAGE
TYPOLOGY SCREENS

WHEN TO USE IT

The screw filter is suitable for many applications, in particular it is suitable for the micro-screening treatment of wastewater of civil and/or industrial origin in treatment plants, and for the filtration of sludge and supernatants.

HOW IT IS MADE

The main components of the FC type screw filter are a multifunctional screw and a semi-cylindrical filtering screen. The standard filtering screen is composed of a semi-cylinder composed of longitudinal wedge wire bars where the distance between the bars determines the filtration opening, but upon request the bars can be replaced by a perforated sheet screen where the filtration opening is determined by the diameter of the chosen hole. The multifunction screw is keyed onto a sturdy designed gearmotornand the various functions it must perform are ensured by different diameters gradually decreasing upwards and by the variability of pitch and thickness depending on the area in which it is located and therefore on the operation which it must carry out.

HOW IT WORKS

In the standard version, the screw filter is installed in a concrete channel where the water to be filtered flows, passing through the screen which blocks all solids with a diameter equal to or greater than the predetermined filtration opening. When the accumulated material on the screen creates a difference in water level between the upstream and downstream of the filter, a differential level sensor starts to rotates the shaft of the multifunction screw. The lower area of the screw has a diameter similar to the diameter of the filtering screen so that through a brush mounted on the external profile of the screw it continuously and effectively cleans the screen. The second area of the screw, of smaller diameter, carries the screened material upwards, draining the water. After drainage the third compaction area begins, where the screw, in order to perform the compaction function, always takes an increasingly smaller pitch and becomes increasingly thicker as it goes upwards. Before being discharged and bagged into a suitable container, the screened material undergoes compaction and dewatering equal to about 50% by weight. The particular feature of this machine, with its completely closed body, prevents the spread of bad odors. The FC screw filter is equipped as standard with a washing system for the filtering screen and the screened material with nozzles and pressurized water.