We feel proud to be the representatives of EVA SCREENS, a division of the Belgian company MOTOGROUP for its Back Raked Screen. EVA SCREENS is particularly specialized in the development of equipment for cleaning and removing all kinds of flotsam and debris from water intakes at power stations, municipal water treatment facilities, rivers, canals, harbors, docks and lakes.
The screens are marketed and promoted by EVA SCREENS Ltd. The screens are covered by patents in several countries:
CENTRAL and NORTH AMERICA;
The screen is a very compact, easy to install unit with transmission system, drive gear motor and grease pump, etc. all incorporated and well protected, in the upper part of the screen.
In brief, we deliver a self contained and ready to use screen, with a lifting capacity of 2000 kg/tine beam, which only has to be connected to the power supply to make the unit immediately operable. The complete installation takes no more than 2 hours per screen, where the screen is simply lowered and positioned in the recesses in the concrete-walls of the water intake structure.
De-watering of the intake structure is not necessary to allow installation or removal.
In the cases where the screens are being retrofitted into an existing concrete structure that is not constructed with the necessary guide recesses, steel or stainless steel guide assemblies can be bolted to the concrete structure. The heavy duty screen offered is able to take out of the waterways all solid material from the size of 30x30 mm to the size of 1000x1000 mm such as waste, garbage bags, refuse, old furniture, wood, drums, treys, plastics and all sorts of water borne weeds such as horn-wort, water-hyacinth, etc.
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.
All screens are “Tailor-Made” and manufactured in mild steel or in stainless steel grades 304 or 316, in widths ranging from ± 1,5 m to ± 4,5 m and ± 2,5 m to ± 18 m high. The screens are manufactured to the requirements of the customer; quotations are calculated taking into account screen dimensions and materials of construction.
In case of overloading (when load is more than 2000 kg): the screen will stop automatically by cos φ controller. The screen will operate again after removing the excess load (or blockage).
Codes and Standards
The ISO International code and standard is applied in carrying out engineering activities and manufacturing of equipment.
The screen is fully reliable and efficient with following main advantages:
1 . A lifting capacity per tine beam of 2000 kg.
2 . Tines protruding between the bars with a length of 600 mm.
3 . An above deck level height of approx. 1600 mm and 2000 mm.
4 . A lifting speed of the waste per tine beam of 8,6 m/min.
5 . Each screen is able to lift out of the water volumes of:
1,00 m x 1,00 m x 1,00 m within the time limit of 1 min.
6 . Installed power 3 kW.