High output, self-cleaning units that use a slow revolving, horizontal cylindrical wedge wire or perforated screen to separate solids from slurry, on the outside (external) surface of the screen.
To ease the function explanation: Looking at the unit from one end with the collection chamber to the left, image the cylindrical drum as a clock face (12 o’clock at the top and 6 at the bottom),
Solids laden slurry is pumped or gravity fed into the unit’s collection chamber and as it fills, runs over a full width weir creating a shallow reservoir of slurry evenly distributed across the entire width of the rotating screen at approx. 10 o’clock.
Revolving clockwise, the drum moves upwards out of the slurry taking solids with particle sizes larger than the screens void (slot) size with it, attached the exterior – the liquid and smaller particles pass through the voids (slots). The attached solids further dewater as the drum revolves and are removed onto the discharge chute @ approx. 3 o’clock by a blade (normally spring loaded brass) that acts like a squeegee.
All the liquid that passes through the screen, passing back through the screen at bottom of the cycle (6 o’clock) that not only washes the back of the screen but also dislodging and flushing out any caught up debris; presenting a clean screen as it moves up into the slurry reservoir. This liquid falls into the collection chamber to be pumped/fed anyway.
Generally used on applications for large volume – not recommended for slurries that have hard or heavy solid particles as they would not adhere to the screen surface and move up to and over the top (12 o’clock) position.
Throughput speed is determined by: