Back Rake Screens
EVA Back raked screens are specialised equipment's for cleaning and removing all kinds of flotsam and debris from water intakes at power stations, municipal water treatment facilities, rivers, canals, harbours, docks and lakes.
- The raking tines insert into the weed or debris mass at the base of the intake channel on the upstream side of the screen. The tines move upwards from the base of the channel.
- All working parts are protected behind the static screen and consequently function on the clean side of the bar screen.
- The raking tines move upward through the bar screen forming an angle of 90° to the bars. At the top of the screen the raking tines describe an arc until they are almost vertical.
- The tines start the retract cycle on reaching the top of the travel, thus cleaning the tines and enabling all recovered waste to drop by free fall to a conveyor belt or a waste container. After cleaning, the tines start the descending motion through the curved section of bars at the top of the unit. No obstruction is possible between the recovered waste and the tines, because the tines retract within the downstream side of the screen frame. No recovered waste can drop behind the screen, because the screens are positioned directly against the concrete working floor. There is no gap or opening between the screen and the working floor. Neither can any waste drop on the working floor because all equipment, i.e. the conveyor belt or waste-container, is positioned directly against the screen.
- Once arriving at the bottom of the screen, the raking tines return gradually to their unfolded position, of 90° in relation to the static bar screen, by turning counter-clockwise.
- All machines have a bar section of ø 42 mm, a spacing between bars of 50 mm or more and a raking tine length of 600 mm protruding in front of the screen bars.
Screens with bar spacing of 16 to 30 mm are also available. These fine screens are used in sewage pump stations. They are equipped with flat bars of 65 by 10 mm, instead of round bars. The above deck level portion of the screen can range in height from 1,6 m to 2,4 m. The height of the curved section above deck level varies depending on the method of discharge, i.e. onto a conveyor or into a container.