High Capacity Drum Screen

After the screen panels have been cleaned sufficiently to eliminate the differential level, a signal is transmitted to stop the screens drive motor. A follow-up device is installed in the control cabinet allowing the screen to complete another rotation before coming to a final halt, thus assuring that all screen panels are completely cleaned. The control cabinet is also equipped with an operating pause timer to start the drive unit at regular intervals (freely chosen) in case the level controller has not triggered a start pulse. This is an additional safety feature to prevent solids from accumulating or incrusting on the screen mesh.The differential level controller overrides the operating pause timer, thus ensuring proper cleaning even in case of sudden accumulation of screenings.

to medium speed of 12 cm/sec. A third, fast speed of 24 cm/sec is provided to cope with an extreme blockage of the screen panels. It is switched on automatically, too. An alarm is triggered if the differential level rises to maximum height, e. g. due to failure of the screens drive unit.

When the differential rises to a pre-set level, the screens drive unit is started to run initially at slow speed of 6 cm/sec. As the screen revolves, the screen panels pass a wash water system mounted at the top above the sludge trough serving to collect and discharge the screenings. The screen panels are washed down by means of two nozzle pipes fitted with different nozzle systems. If the differential level continues to rise, the drive is automatically accelerated

Water that has undergone preliminary cleaning by bar screens enters the drum screen through the inlet openings on both sides and passes through the submerged screen mesh panels. Debris contained in the inlet flow being larger than the mesh size is thus retained inside the screen. As the screen mesh becomes blocked, a differential water level occurs between the inlet and outlet sides of the screen. This differential is detected and electrically processed by a level controller.

Way of Functioning

Water Inlet Screen for remove debris at inlet flow