Mobile screening falls into two main categories: trommel screens (rotating drums) and vibrating screens (incline, horizontal, or banana screens). Each technology has clear advantages depending on your material, moisture content, and production requirements.
A trommel uses a rotating cylindrical drum with screen panels. Material enters one end, tumbles through the drum, and undersized material falls through the screen openings. Oversize continues out the far end. The tumbling action breaks up clumps and separates sticky material that would blind a vibrating screen.
Vibrating screens use a flat or slightly inclined deck that shakes rapidly to move material across screen surfaces. Multiple decks allow separation into 3 or 4 products simultaneously. Material stratifies by size as it moves across the deck — fines drop through early, coarse material travels to the end.
| Factor | Trommel Screen | Vibrating Screen |
|---|---|---|
| Best material | Wet, sticky, irregular (topsoil, compost, C&D) | Dry, consistent (crushed stone, gravel, sand) |
| Moisture tolerance | Excellent — handles 20%+ moisture | Poor to moderate — blinds with wet clay |
| Number of products | 2-3 (oversized, screened, fines) | 3-4 (multiple deck separations) |
| Throughput | 100 – 400 TPH typical | 200 – 800 TPH typical |
| Screening precision | Moderate (tumbling is less precise) | High (vibration stratifies material well) |
| Screen media life | Longer (less abrasion from tumbling) | Shorter (high-frequency vibration accelerates wear) |
| Maintenance | Lower (fewer moving parts) | Higher (vibrating mechanism, bearings, springs) |
| Noise | Lower | Higher |
| New price range | $200,000 – $575,000 | $150,000 – $500,000 |