Rotating drum trommel screens work well for sizing and separating any mix of materials. A variety of screen opening sizes are available, and multiple sizes can be installed on the same trommel drum for graduated sizing and separating — one drum, several size fractions, no moving screen decks to feed or maintain.
What Is a Trommel Screen?
A trommel screen — also called a rotating drum screen — is a perforated cylinder that turns slowly on its axis while material passes through it. As the drum rotates, the material inside tumbles: it is lifted partway up the drum wall, falls back, and works its way toward the discharge end. Every tumble presents the material to the screen surface again, so pieces smaller than the openings find a hole and fall through, while everything larger travels the length of the drum and discharges off the end. The tumbling action also helps break up clumps and shake small pieces loose from larger ones, so a trommel handles a dirty, commingled stream well. The result is separation by size, done with one slow-turning drum — the mechanical simplicity behind the trommel's reputation as a low-cost way to screen a mixed stream.
Graduated Screening — Multiple Opening Sizes on One Drum
A drum with a single opening size splits a stream two ways: what falls through and what doesn't. The trommel's real trick is graduated screening. Multiple screen opening sizes can be installed on the same trommel drum, arranged from smallest at the infeed end to largest toward the discharge. Material meets the smallest openings first, so the finest fraction drops out early; as the remaining material travels down the drum, each successively larger opening size takes its cut. Whatever is too large for the last section discharges off the end of the drum as oversize.
Each section drops its fraction into its own collection point below the drum, so a single rotating drum trommel screen can replace what would otherwise take several separate screening steps — one machine producing three, four, or more sized streams in a single pass.
What Materials Does a Trommel Screen Sort?
Any mix that separates by size is a candidate. Common applications for the machine type include:
- Glass & cans — broken glass falls through small openings while whole aluminum and tin cans carry over, splitting a container stream into a glass fraction and a can fraction. The trommel pictured above was built for exactly this duty.
- Fines removal — grit, dirt, caps, and glass shards drop out of a single-stream or solid waste line early, before they grind against belts, bearings, and downstream equipment.
- Compost & organics — finished compost screens away from oversize wood and unbroken material, which can be returned for further processing.
- Construction & demolition (C&D) debris — soil and small rubble separate from the larger wood, metal, and concrete that sorters or machines recover downstream.
Where a Trommel Sits in a Recycling Line
A trommel usually earns its keep early in the line. Screening by size ahead of the sort means the people and machines downstream see a cleaner, more uniform stream — and the abrasive fines that wear out belts are gone before they travel the length of the plant.
An infeed conveyor meters material into the high end of the drum at a controlled rate — surging a trommel buries the screen surface just as it buries a flat screen. Below the drum, collection hoppers land each undersize fraction on its own takeaway conveyor. Oversize off the end of the drum carries on to the next stage: a sort line, an eddy current separator, an overhead magnet, or a baler, depending on the plant. The trommel is one machine in that chain — the conveyors, chutes, and structures around it are what turn it into a working line.
Trommel, Disc Screen, or Vibratory Screen?
All three screen by size, and plenty of plants run more than one. A trommel tumbles material inside a rotating drum — a simple, forgiving action that suits dirty, commingled streams and graduated multi-fraction screening. A disc screen walks material across banks of rotating discs and also separates flat fiber from rounder containers — the workhorse of single-stream paper lines. A vibratory screen stratifies material on a vibrating deck for precise sizing. Remcon builds trommel drum screens in-house; disc and vibratory screens we source from their manufacturers and integrate into the line. Not sure which screen your material needs? Tell us the material mix and we'll help you sort it out.
Trommel Screens from Remcon
Remcon builds multiple types of equipment designed for the sorting and separation of different types and sizes of materials, and trommel drum screens are part of that lineup — see the full sorting & separation catalog. We specialize in custom designed and fabricated equipment: the drum, its screen opening sizes, the enclosure, and the collection hoppers are configured to your material and your building, and the trommel is integrated with the conveyors that feed it and take each fraction away. Every Remcon trommel is designed and fabricated at our Airway Heights (Spokane), Washington shop, then shipped and installed nationwide.
Trommel Screen Specifications
Because every trommel is built to order, the numbers come from your application rather than a catalog page:
| Specification | Remcon approach |
|---|---|
| Drum diameter & length | Sized to the application — quoted per job |
| Screen openings | A variety of opening sizes available, chosen for the fractions you need to pull |
| Graduated sections | Multiple opening sizes can be installed on the same drum for graduated sizing and separating |
| Fractions produced | One undersize fraction per opening size, plus oversize off the end of the drum |
| Enclosure & collection | Guarding, enclosure panels, and collection hoppers configured to the application |
| Infeed & takeaway | Integrated with the conveyors that feed the drum and carry each fraction away |
| Installation | Shipped and installed nationwide from Airway Heights, WA |
Trommel Screen FAQ
What is a trommel screen?
A trommel screen — also called a rotating drum screen — is a rotating perforated drum that sizes and separates a mix of materials. As the drum turns, material tumbles inside it: pieces smaller than the screen openings fall through, and larger pieces travel on to discharge at the far end. Rotating drum trommel screens work well for sizing and separating any mix of materials.
How does a trommel screen separate different sizes of material?
A trommel separates by the size of its screen openings — anything that fits through the openings falls through, and everything larger keeps traveling down the drum. A variety of screen opening sizes are available, and multiple sizes can be installed on the same trommel drum, smallest openings first and largest last, so a single drum produces several clean size fractions in one pass, each dropping into its own collection point.
What materials can a trommel screen handle?
Any mix of materials that separates by size. Common uses include separating broken glass from aluminum and tin cans in container streams, dropping fines and grit out of single-stream recycling, screening finished compost away from oversize, and pulling dirt and small debris out of mixed construction and demolition (C&D) loads. Remcon has built trommel drum screens for jobs such as glass and aluminum can separation.
How much does a trommel screen cost?
Every Remcon trommel is custom designed and built, so price is quoted per job rather than from a catalog. The main cost drivers are drum size, the number of screen opening sizes on the drum, the drive arrangement, enclosures and guarding, and the conveyors and chutes that feed the drum and carry each fraction away. Tell us the material mix and what has to come out of it and we will quote it. Call (509) 244-9439.
We specialize in custom designed and fabricated equipment and can work with you to design a solution that will work well for your needs. Contact us to discuss a trommel for your line or to get a quote.
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