Catalogue

Plants, equipment and machines for water treatment

GNAFO

The perforated sheet belt screen is installed in various depth channels of small and medium size civil or industrial wastewater treatment plants. It allows to discharge the screened material to the needed height and complies with fine screening requirements. It is mainly composed of a sturdy frame in press-bended steel sheet reinforced by steel standard sections, a belt with mobile elements in stainless steel perforated sheet properly shaped and mounted on the links of a couple of roller chains, two cogwheel fitted in the upper part of the screen for moving the chains, two static counterwheels fitted in the lower part of the screen, a gearmotor with suitable power for the moving of the mobile part of the screen, a cleaning system composed of a rotating brush in synthetic fiber, a gearmotor with suitable power for the moving of the cleaning brush and the pre-arrangement for an optional water washing system by means of solenoid valves and nozzles.
The filtering gap is the same as the holes of the perforated sheet of the mobile elements. These elements are shaped and fixed on the links of the chains in such a way that the filtering belt presents a surface made by overhanging steps that allows the lifting of the filtered screenings even if hardly liftable, avoiding the accident falling. For particular kind of screenings it is possible to increase the surface of the steps mounting on the belt three or more combs. Most of the time the screen doesn't have moving parts; only when the difference in height between upstream and downstream reaches a threshold value the gearmotor starts the belt movement.
The belt cleaning occurs when it is in movement, thanks to the cleaning system that supports the screened material fall on the chute below. The result is a screen with an automatic cleaning device of simple construction and great safety. A further cleaning is guaranted when filtered flow crosses again the belt through its downstream side counterwashing it. Finally a third extra washing device (optional) using service water, by means of nozzles can be used, if needed.

Strenghts

• FINE SCREENING.
• HARDLY LIFTABLE MATERIAL SCREENING THANKS TO THE STEP PROFILE.
• SIMPLICITY.
• STURDINESS.
• BELT CLEANING ENSURED BY 3 CLEANING SYSTEMS.
• ABSENCE OF MECHANICAL MOVING PART  IN WATER.