The bridge is supported at the tank centre by a tripod and trunnion arrangement that accommodates small variations in tank geometry. A diffuser drum at the centre helps manage inlet flow, while the bridge drive system at the perimeter provides controlled, dependable rotation.
Scraper blades suspended from the bridge direct sediment towards the central hopper, with renewable wearing edges to support long service life. A separate scum blade sweeps floating material across the water surface towards the scum removal point.
Diffuser Drum, Inlet Pipe and Tripod
The centre pivot assembly is mounted on a fabricated mild steel tripod fixed to the tank floor. A diffuser drum is suspended from the rotating bridge and includes a baffled scum outlet to help manage flow conditions at the tank centre. The inlet pipe rises through the central hopper and is vertically supported on a duckfoot bend arrangement.
KEY FEATURES:
OPTIONAL FEATURES:
The trailing arm scraper arrangement uses tubular arms hinged from the bridge, allowing the scrapers to remain positively located while also rising and falling with variations in tank floor level. The scrapers are bolted to supports suspended from the bridge and fitted with renewable wearing edges for easier long-term maintenance.
Scum baffle plates are positioned around the tank perimeter to prevent surface scum passing over the outlet weir. Located inboard of the weir wall, they help contain floating material and support more effective scum collection.
The fabricated scum skimming blade is mounted to the bridge structure and works with the scum baffle plate to form a scum catchment zone as the bridge rotates. Floating material is directed towards the tank perimeter and deposited into the scum removal unit once per revolution.
The scum removal unit is mounted on the launder channel so that as the bridge passes over, the scum board allows the scum to be deposited into a collection box. A cam hanging of the bridge activates the cylindrical collection box, allowing the scum to be deposited through the collection opening & flushed away.
A central electrical collector column is mounted at walkway height and contains the slip ring assembly, which communicates power from a static external supply to the rotating bridge drive unit.
The slip ring assembly comprises of Brass slip rings and double leg, light duty brush holders (callipers) fitted with copper graphite brushes suitable rated. The bottom ring/brush is permanently earthed to the shaft and base to provide continuous bonding.
The unit comprises a series of brushes fitted to support brackets to clean the effluent channel sidewalls and weir top and rear of the weir plates as the bridge rotates. There are also offset brushes, which rest on the channel floor, from a pivoted bracket.
The bridge can only be restarted by releasing the emergency stop button by depressing the button whilst twisting it to the left. The button is spring-loaded to return to its original position.
To discuss rotating half bridge scrapers or find out how George Green can help your business, please get in touch.
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