Brackett Green - Continuous Chain Raked Bar Screens
The Brackett Green® continuous chain raked bar screen (CCRBS) is used mainly on coarse screening of sewage or raw water intake. The unit is fixed on guide angles mounted to the vertical sides of the civil works. Horizontal raking beams (with teeth) move up the bars using two continuous chains, to a debris plate where a wiper dislodges the debris from the raking beam into a discharge chute. The number of raking beams depends on the amount of debris typically collected.
- Simple, robust and compact design
- Continuous removal of small debris at high volumes
- Self-contained units can be installed with one lift
- Short cleaning cycle time
This robust, heavy-duty type of raking machine is a self-contained unit mainly used on coarse screening of sewage or raw water intakes. The bar screen is angled at 15° from the vertical and is designed for operation in channels up to 4m wide and 15m deep. The screening bars come in sections that are bolted to horizontal beams mounted across the channel. The unit is located on guide angles attached to the vertical sides of the civil work, for ease of installation and removal.
- High debris removal capacity within a small footprint
- Suitable for jellyfish and sea grass removal
Horizontal raking beams provide continuous front raking of the vertical screen grid. Screening bars are arranged across the channel, and the area between the top of the bars and the debris discharge point has a flat debris plate or civil works apron wall for larger machines.
All models have a shaft-mounted weatherproof gearbox and motor directly positioned on the main drive shaft, which is supported by roller bearings in the head section of the machine frame. The bearings have adjusting screws to allow for chain tensioning, and an electronic power sensor provides overload protection.
Raking beams are bolted to each side of the roller chains and have teeth profiled to engage with the screening bars. The position of the raking beam is firmly controlled by either the liquid level in the channel, the differential level drop across the screen, from timers, or from a combination of these three methods, ensuring correct engagement with the screen bars. Although the number of raking beams provided is determined by the anticipated solids loading volume, our design also includes a second beam that engages the bottom of the bars at approximately the same time that the preceding beam clears the top of the screening area for more efficient debris removal.
During operation, each horizontal raking beam moves upwards along the bars and then carries the collected debris across the flat plate to the discharge point, where a wiper blade pushes the debris off the rake teeth onto a discharge chute that leads to a skip, floor channel or conveyor as required. The wiper blade ensures that all debris is removed from the rakes and falls back into position after the beam has passed.
The continuous chain raked bar screen requires minimal civil works and can be positioned directly into an existing channel in one direct lift.