With whatever screening media you are using, make sure that the screen wears out and does not break. If the screen breaks see where it breaks.

1. If it breaks at the feed end of the deck:
  • Make sure to spread the material feed evenly to the full width of the screen bed in order to use the complete screening surface of the deck.
  • Reduce feed height to avoid high impact on the screening media.
  • Use the correct screening media, you may want to use at the feed end perforated plates, rubber or polyurethane that have a higher resistance to high impact and abrasion.
2. If it breaks along the support bars:
  • Check that the screen is fitted correctly and at the correct tension and re-check this at regular intervals. This is the main cause of premature screen failure. If the screen is loose it will be vibrating and banging the support bars, creating micro fractures along the support bar that will result in screen damage. Also make sure to allow enough space (H) on both sides of the screen to tighten it symmetrically, the hook of the screen should never touch the machine’s side.
  • Check the correct position of the side plates one side plate on one screen, so that there is an even tension on the screen. If one side plate is tensing two screens, the screens will never be tensed correctly.
  • When tightened, the mesh should form a single body with the deck, otherwise the mesh will bang into the screen rack and will end up getting broken.
  • If you are using metallic screens with wire diameter over 6.3mm. you may need to use U-Bars or J-Bars to fix the mesh to the screen deck.
  • On meshes with thick wires, greater than 6.3 mm, there is the possibility of the tension plates coming loose despite having tightened the screws. It is necessary to check and retighten after ten hours of screening.
  • Check you use rubber liners on the deck’s support bars and that they are in good condition. When the rubber liner is worn or broken it will create gaps between the mesh and the deck, creating soft and weak areas on the mesh.
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  • If you are using self-cleaning screens make sure the polyurethane bands coincide with the deck’s support bars, if they don’t it will generate potential blind areas and loose screening surfaces.
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  • If you are using polyurethane or rubber screens make sure the blind areas coincide with the deck’s support bars.
3. If it breaks along the edge of the screening media’s hook:
  • Check that the side plate fits correctly on the screen’s hook (1). If the side plate touches point 2, the hook will turn, breaking the mesh at point 3.
Overlap types

Metallic overlap

Polyurethane overlap

All screens with apertures under 14 mm should have overlap to avoid contamination between screens.

Tension types

Side tension

End tension

Split side tension – Type 1

S type end tension

Split side tension – Type 2

Side tension (optional):

without overlap / with overlap

End tension:

without overlap screening

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Guidance chart for mesh aperture size
CLASSIFICATION – Approximate correspondence between PARTICLE SIZE and MESH APERTURE
Particle size mm Metallic Screen Doblonda Screen PU Screen Rubber Screen
Natural Crushed Natural Crushed Natural Crushed Natural Crushed
1 1,12 1,25 1 1,2 – – – –
1,25 1,4 1,6 1,3 1,5 – – – –
1,6 1,8 2 1,75 2 – – – –
2 2,24 2,5 2,2 2,5 – – – –
2,5 2,8 3,15 2,5 3 – – – –
3,5 3,55 4 3,3 3,5 – – – –
4 4,5 5 4,2 4,5 5 5,6 5,5 6,3
5 5,6 6,3 5,5 6 6,3 7,1 6,5 7,5
6,5 7,1 8 7 7,5 7,1 8,5 7,5 8,5
7,1 8 9 7,5 8 8,5 9,5 8,5 9,5
8 9 10 9 10 9,5 10,5 9,5 10,5
9 10 11,2 10 11 10,5 11,5 11 12
10 11,2 12,5 11 12 12 13 12,5 13,5
11,2 12,5 14 12 13 13,5 14,5 14,5 15,5
12,6 14 15 14 15 14,5 16 16 17
14 16 17 15 16 16,5 18 18 19
16 18 19 18 19 18,5 20 20 21
18 20 21 20 21 20 23 23 24
20 22 23 22 23 22,4 25 25 26
22,4 24 25 24 25 25 28 27 29
25 27 28 27 28 28 31,5 31,5 33,5
28 30 31,5 30 31,5 31,5 35,5 35 37
31,5 34 35,5 34 35,5 35,5 38 38 40
35,5 38 40 38 40 38 40 43 45
40 43 45 43 45 42 45 50 52
45 48 50 – – 48 50 55 57
50 53 56 – – 53 56 60 62
63 65 70 – – 65 68 74 76
80 85 90 – – 85 90 98 100
100 105 112 – – 105 112 115 120
120 – – – – – – 135 140
150 – – – – – – 170 175

Note: The data shown is recommended for dry screening at an inclination of 12º to 18º