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We define pegging as feed material that lodges in screen apertures. On conventional screen machines there is not enough force (only 5 g) to dislodge
and reject the material that pegs into the apertures. Near-sized material, material only slightly larger than the opening and shaped such that it can
drop partway into the screen openings, can pose a serious problem. If there is a lot of ‘near sized’ the screen can quickly blind and stop the screen from functioning.
The Liwell® Screen operates on the "Flip-Flow" principle under which elastic polyurethane screen mats are alternately tensioned and relaxed. In the
final tensioning phase of the cycle, the screen mats are stretched, changing the surface of the screen mat and altering the shape of the aperture.
Adherent particles burst away. Acceleration forces on the LIWELL® screen mats of up to 50 g are achieved, whereas the machine structure gets 2 or 3 g only,
consequently, the LIWELL® screen machines operate very reliably. The screen deck operates free from pegging and blinding even with difficult feed materials.
The image below shows wood chips that have pegged the openings of a screen.
The images below show opposite sides of the same screen pegged with stones.
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