Mechanical sizing of waste flows can be executed with various screens. Mesh-sizes vary from 4 to 500 mm. Large parts are usually first processed by crushers or shredders, separated manually or simply broken by a grab. The type of screen required depends on the type, size and density of the material to be screened. Examples of REDOX screens:
The REDOX trommels are designed to screen any kind of construction and demolition waste. The screen meshes of a REDOX trommel can vary from 200 mm down to 15 mm. In a sorting line they are mostly used as a first separation step in the separating / sorting process.
The material to be screened is brought into the trommel with a belt conveyor. The material then moves through the trommel and the material smaller than the screen mesh fall through. The fraction larger than the screen mesh will come out of the trommel on the other side.
Capacities of the REDOX trommels can be up to 160 m3/hour.
| Star screens are also used for demolition and construction waste. REDOX applies them as a second or third screening step and are soften used to screen fractions from 30-40 mm down to 10 mm.
Functioning of the star screen
The material to be screened is brought or falls onto the star screen. The rotating stars allow the material to be transported. During this material transport, the fines are removed by falling through the spacing between the fingers of the star or the spacing between the stars itself. The oversized material transported off the end of the star deck onto a conveyor belt or into a bay.
Advantages star screens: - compact construction
- good material spread
- high processing capacity
- adjustable star deck speed
- heavy-duty construction
- reduced operating noise (soft stars)
- low maintenance
- stars are easily replacable
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Construction and demolition waste often contain sand fractions. For small fraction like sand, REDOX applies a stretch deck screen. Even when the materials are moist, a strech deck screen will still be able to screen at the desired screen mess without clogging.
Functioning of the stretch deck screens
Elastic polyurethane screen panels are alternately tensioned and relaxed. This gives a "trampoline" effect. In the final tensioning phase, the screen panels are stretched changing the surface of the screen mat. Adherent particles burst away. Acceleration forces of up to 50G are achieved, whereas the machine structure gets 2 or 3G only. The screen deck operates free from blinding even with difficult feed materials.
Advantages stretch deck screens: - Effective classifying (also with damped and difficult materials)
- High availability because of the self-cleaning screen deck
- Good flexibility
- Compact construction
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Stretch deck screen
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Stretch deck screen
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