Pulper Screen Plate
The pulper screen plate is the core “filtering” component of the hydrapulper, located on the inner wall or bottom of the pulper cylinder. Through the shear, impact, and friction between the high-speed rotating rotor and the screen plate, impurity separation and coarse selection of the pulp are achieved. It directly determines the cleanliness and efficiency of the pulp after crushing.
The Function of Screen Plate
- Coarse purification: Separate large particle impurities such as iron nails, stones, plastic sheets, ropes, and sand particles from waste paper pulp.
- Control the fineness of the pulp: By adjusting the pore size, control the retention and discharge of fiber bundles and impurities in the pulp.
- Protection equipment: prevent large impurities from entering subsequent pipelines, refiner, and screening machines to avoid equipment damage.
Technical Parameter of Pulper Screen Plate
| Parameter | Features |
| Hole/Slot | Waste paper pulp: 2-6 mm (seam); Wood pulp/high-value waste paper: 1-3 mm; large impurities: choose large holes/wide slots. |
| Opening Rate | Opening rate ↑ → large processing capacity ↑, but prone to impurities; Opening rate ↓ → good filtering effect ↑, but prone to clogging. |
| Material | Wear resistant: high chromium alloy, wear-resistant steel (NM400+);
Universal: Stainless steel 304/316L. |
| Thickness | Determine lifespan. Conventional 10-20 mm; high concentration/large impurity conditions require 25 mm or more. |
| Surface Treatment | Wear resistant alloys significantly extend their lifespan. |
Screen Plate Material Comparation
| Material | Advantages | Suitable Application |
| Stainless steel (304/316L) | Corrosion resistant, easy to clean, and aesthetically pleasing | Wood pulp, low impurity, food grade/specialty paper |
| Wear resistant steel (NM400/NM500) | Extremely high wear resistance and impact resistance | Waste paper pulp, high sand content, and high wear conditions |
| High chromium alloy | Ultra wear-resistant, impact resistant, and longest lifespan | Heavy waste paper, high concentration pulper, long-term continuous operation |
Normal Problem and Reason for Screen Plate
Screen Plate Blockage (Hole Blockage)
Reason: high pulp concentration, fiber agglomeration, excessive impurities, and insufficient porosity.
Solution: Reduce concentration, strengthen impurity removal, and regularly rinse with high-pressure water.
Screen Plate Wear/Perforation
Reason: Impurities (stones, iron nails) impact, insufficient material hardness, and high rotational speed.
Solution: Choose high wear-resistant materials, install iron remover, and control speed.
Screen Plate Deformation/Broken
Reason: Improper installation, uneven stress, thermal expansion and contraction, frequent start stop.
Solution: Standardized installation, uniform fastening, and good insulation.
Selection of Pulper Screen Plate
Selecting the appropriate screen plate ensures the high-efficiency disintegration of the hydrapulper and extends the service life of the equipment. The selection process should be based on the following factors:
- Pulp Type:
For waste paper pulp with a high impurity content, screen plate with larger hole diameters should be selected, with priority given to wear resistance. For virgin pulp or recycled pulp, screen plate with smaller hole diameters may be used; considering wear resistance, stainless steel material is recommended to ensure superior fiber quality. - Pulp Consistency:
High-consistency pulping requires screen plate of greater thickness and higher material strength to withstand high-impact forces and abrasion, thereby preventing premature plate failure. - Pulp Impurities:
If the pulp contains significant amounts of grit, metal fragments, or similar impurities, screen plate featuring high impact resistance and superior wear resistance must be utilized to prevent premature failure. - Production Capacity Requirements:
While increasing the open area ratio of the screen plate boosts pulp throughput, it also compromises screening precision to a certain extent. Therefore, the selection process requires striking a balance between production capacity demands and the required purity of the pulp.