Factory Footage · Live Trial Run

1. Definition

A roller screen (also known as a roller-grizzly / shaft screen) is a screening machine consisting of multiple parallel rotating shafts fitted with discs or toothed discs. Material fed onto a slightly inclined roller deck is conveyed forward by shaft rotation and gravity: particles smaller than the gaps between rollers drop through as undersize, while larger particles travel along the deck and discharge at the end as oversize — screening and conveying happen simultaneously.

2. Structure & Working Principle

Main structure: frame (screen housing), multiple roller shafts, discs / toothed discs, drive unit (motor + gearbox, with chain or gear transmission), feed inlet, fines outlet, oversize outlet.

Workflow: Feeding → conveyed by rollers → fines pass through → oversize discharges

• Feeding: material is fed evenly from the inlet onto the inclined roller deck;
• Conveying: all shafts rotate in the same direction; material moves toward the discharge end through roller friction and deck slope;
• Passing through: fines fall between the rollers into the undersize hopper below;
• Discharge: coarse lumps roll along the deck and exit through the oversize outlet at the end.

3. Classification

By roller surface:

• Disc type: flat discs on the shafts, uniform gaps; used for general size classification;
• Toothed-disc type: toothed discs on the shafts; better at breaking arches (bridging) and handling wet, sticky materials.

By drive:

• Central drive: one motor drives all shafts via chain/gear;
• Group drive: multiple motors drive shaft groups separately.

By installation:

• Fixed (most common); mobile (for temporary or relocatable jobs).

4. Key Technical Parameters (typical ranges)

Note: typical ranges (indicative); refer to specific models and manufacturer data.

5. Advantages & Limitations

Advantages:

• High throughput — suited to high-volume bulk pre-screening;
• Anti-blinding — handles wet, sticky, clay-bearing materials well;
• Smooth running, low noise, less dust;
• Screening and conveying combined in one; compact and easy to integrate into a system.

Limitations:

• More complex structure and higher cost;
• Gap size is fixed; changing the cut point requires replacing discs;
• Rollers (toothed discs) wear faster; more maintenance;
• Limited separation accuracy — not intended for fine classification;
• Efficiency drops for very fine materials (e.g., below ~10 mm).

6. Typical Applications

Coal handling systems in thermal power plants (pre-screening of raw coal and coal gangue), coal preparation plants, coking plants (coke screening), metallurgy (sinter, pellets), building materials (limestone), and mining (ore pre-screening) — coarse, high-volume bulk screening tasks.

7. Common Faults & Maintenance