Rotary drum screen.
A perforated drum set across the channel: the flow passes through the drum surface, the material that will not pass is carried round on the drum, and a wash bar cleans it off above the water line.
How a rotary drum screen works
The drum is a perforated cylinder mounted across the inlet channel and driven slowly at one end. The flow passes through the drum surface, and the material that will not pass is carried on the drum as it turns; above the water line a wash bar sprays the drum and flushes that material into a collecting trough or a screw conveyor, so the apertures are cleaned on every revolution instead of blinding over. The wash does the job a rake does on a bar screen, which is why the drum screen has no rake mechanism in the water: fewer moving parts in the flow. The drum spans the channel, so the unit takes its space in the width of the inlet rather than in its length, and the screens are used where the flow is modest — a small or medium plant, or the inlet of an industrial pretreatment train.
Rotary drum screen, channel type
The drum, its shaft and the drive are carried on one base frame that is set into the channel. The drive is a geared motor at the drum head, the wash bar runs along the length of the drum above the water line, and the discharge is arranged to suit the screenings handling the site already has — a trough, a conveyor or a container. Inspection is from the channel walkway, so the routine check is made without lifting the unit out of the water.
Applications
Small and medium plants
The inlet screening duty at a plant where the flow is modest and a compact unit suits the inlet structure better than an inclined bar screen.
Industrial pretreatment
Screening the inlet of an industrial treatment train, where the coarse material has to be taken out of the flow ahead of the units downstream.
Screening ahead of filtration
Protecting a filtration or membrane stage by removing the coarse material before it reaches the fine surface.
Delivery
Units are assembled and tested at our factory before shipment, then shipped with export documentation. The channel width, the drum aperture and the discharge arrangement are confirmed against the site before the build. Loading arrangement and delivery schedule: [to be confirmed with factory].
