DRUM SCREENS
WATER FLOWS FROM INSIDE TO OUTSIDE

DESCRIPTION

The drum screen is installed in a concrete chamber between two parallel side walls with large apertures. The drum consists of a cylindrical rotor with a cylindrical surface made of side-by-side rectangular mesh panels. The rotor has two bearings and a drive at deck level. The panels travel down into the water. The water flows into the inside of the drum screen via the two side-wall apertures and flows out after passing through the mesh via the screen chamber’s back outlet.

The debris-laden panels travel up to the deck level. One or two spray pipes with fantail jet nozzles set on the downstream side of the panels within the screen’s head structure, back-wash the panels and remove the debris which are projected into an internal collection trough. They travel in a deck flume to the debris disposal system (basket, separator, etc.).

The screens are normally stopped and are washed periodically when obstructed by the debris. Permanent rotation can be provided.

ADVANTAGES

• 90 years’ experience

• Permanently resists high levels of head-loss

• Large debris-handling capacity

• Well-suited for permanent rotation

• Compact civil structure

• Fully-automatic

• Fish-friendly option

• Next to no maintenance required.

• Cost effective

NECESSARY ANCILLARIES

• Spray-water supply circuit

• Head-loss monitoring system

• Electrical control cabinet

• Upstream bar rack (25 to 75 mm spacing (1 to 3”))

• Pit dewatering stoplogs

• Trash collection system (basket, etc.)

SIZES AND DATA

• Mesh aperture from 1x1 to 10x10 mm (0.04 to 3/8”), or less upon special request

• Flow rate up to 120000 m3/h (300000 gpm)

• Tidal variation: no practical limit

• Panel frame useful width: 1.3 to 6 m (2 to 13 ft)

Wider machines on special request (two-wheel layout)

OPTIONAL FEATURES

• Two or three-speed operation

• Seismic qualification

• Special high travel speed design for handling very heavy debris loads

• Jellyfish lifting trays

• Screening medium resistant to fiber build-up

• Screening medium preventing jellyfish adherence

• Low pressure water-life protection system

• “Scoop-a-fishTM” total fish survival system

• Atex compliance

• By-pass valves