Sludge scraper bridge with controlled extraction The sludge scraper bridge with controlled extraction is installed on a sedimentation tank with flat and/or inclined bottom. The inlet of the water to be treated and the sludge extraction occur coaxially towards the centre of the tank, through two pipes.
The bridge consists of tubular girder that rotates about a central pin fixed to a central steel tower and at the opposed end it leans on the tank wall, where a carriage with two rubber wheels, and idle and a driving one, slides. A truss structure is fixed below the girder to support the bottom scrapers shaped as a vomer, each allowing the conveying of sludge to the inlet of the relevant suction pipe.
Each suction pipe is fitted with a telescopic valve, manually adjusted to extract the desired amount of sludge. After that, the sludge is carried through piping to a main collecting tank fixed by brackets to the central steel post and then is finally discharged outside the tank through piping. The sludge suction system consists of a blower controlled through an electrical panel where the signals sent by level probes located inside the clear polycarbonate tank arrive; a probe signals the minimum level, another one the mean desired level and one the maximum level, while an emergency probe trips in the event of a failure.
The sludge scraper bridge with controlled extraction can be fitted with a suspended solid collecting system, usually consisting in a blade fitted at the front, shaped so as to push the solids from the middle of the tank towards the foam collecting tank secured to the tank wall, which is opened by the collecting blade that turns a turning cover by a lever system. From the tank, such residues are discharged, for example with the aid of a telescopic valve and a suction pump. To facilitate the suspended solid transport, it is also possible to fit a foam accelerator at about halfway of the foaming vane, which can operate both automatically or manually, according to the operating needs. On the carriage of the controlled extraction sludge scraper bridge it is also possible to install a stroke path cleaning device which automatically (thanks to a humidity and temperature sensor) cleans the bridge wheel sliding zone and of the anti-freeze fluid that falls on the stroke path (thanks to a solenoid valve control). The clean water flows into the pipe through a series of holes. To keep the pipe circumference clean, a cleaning mechanism is mounted which thanks to the rotating feeding movement of the bridge, cleans the top of the pipe. The brush can then be lifted manually. Drawing of the flat bottom extraction bridge, model PRR 3810
 Drawing of the inclined bottom extraction bridge, radius + 1/3, model PRR 3810
 Drawing of the flat bottom extraction bridge with pumps, model PRR 3810
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