The most frequent cause of downtime in a sorting plant is not a breakdown, it is a blinded screen. Household waste is wet, sticky and fibrous, and particles lodge in the mesh until nothing passes through any more. A flip flow screen is engineered for exactly the material that blinds everything else.
The solution is ingenious: the screen is not a rigid mesh but an elastic panel. The panel and a counterweight form two independent vibrating masses that move out of phase. The result is that one section of the screen is under tension while the adjacent section is slack, and the geometry of the openings changes constantly. No particle has time to lodge. See the full range of waste sorting equipment and where each machine sits in the flow.
Key Advantages of a Flip Flow Screen
• Blinding effectively disappears, the alternating tension continuously changes the shape of the openings, so wet particles cannot wedge into the mesh the way they do on any fixed screen.
• It runs on the hardest material, wet municipal waste, plastic film, damp paper, organic waste, textile fibres, precisely the flows a perforated drum refuses.
• No stops for manual cleaning, it removes the most expensive lost time in a sorting plant, halting the line to clear a blinded screen.
• Bouncing motion, not sliding, the elastic panel stretches and snaps back, throwing material forward, which creates particle collisions and breaks up clumps.
• It protects the downstream investment, by removing the fine, wet fraction at the start, optical sorters and air separators work on clean material and far more accurately.
• Long-lasting screen panels, because they are not subject to continuous abrasive rubbing like a rigid screen, elastic panels have a longer service life.
Technical Specifications, Flip Flow Screen
| Parameter | 1.2 m width | 1.6 m width | 2.0 m width |
|---|---|---|---|
| Working width (mm) | 1200 | 1600 | 2000 |
| Principle | Dual vibrating mass | Dual vibrating mass | Dual vibrating mass |
| Screening surface | Elastic panel | Elastic panel | Elastic panel |
| Counterweight | Adjustable | Adjustable | Adjustable |
| Screen box | Inclined | Inclined | Inclined |
| Self-cleaning | Yes, by alternating tension | Yes, by alternating tension | Yes, by alternating tension |
Throughput depends on moisture, inlet particle size and the chosen cut point, so it is calculated at configuration rather than given in a table. Tell us your flow composition and we set the width and the number of sections.
Applications for Screening Wet Waste
• Municipal waste sorting plants, separating the fine and organic fraction, immediately after pre-shredding and bag opening.
• Mechanical biological treatment plants, preparing the organic fraction for composting or anaerobic digestion.
• Construction and demolition waste, separating soil and fine rubble from wood, metal and plastic.
• Commercial and industrial waste, screening mixed packaging, where moisture varies widely from batch to batch.
• Composting, removing oversized contaminants from finished compost, on material with high moisture content.
How It Works
Material is fed onto the inclined screen deck at the upper end. The drive system rhythmically pulls the two vibrating masses, the elastic panel and the counterweight, in opposite phases. Picture the panel as a trampoline sheet pulled taut and then allowed to go slack, in a wave that travels across the width of the machine. When a section is taut, the openings become slightly smaller and more defined, and the material on that section is propelled sharply forward and upward. Immediately after, the section goes slack, the openings relax and widen, and small particles fall through under gravity. The cycle repeats rapidly and continuously across the whole surface. Particles are thrown forward in the tension phase, collide with each other, and get the chance to reorient during the relaxation phase. The small fraction, soil, broken glass, fine organics, falls below. The large fraction, bottles, cans, cardboard, textiles, travels up the incline and is discharged at the top.
Selection Guide
A flip flow screen is chosen when material moisture is the main problem. If your flow is dry and relatively clean, a trommel screen is simpler and cheaper. If it is damp but not extreme, a star screen may be enough. But if you have freshly collected household waste with food residue, or you operate in a high-rainfall region, this is the machine for the job. Width is chosen from line throughput, and the cut point from what you want to remove: below 40 mm for the fine organic fraction, around 80 mm for preparing recyclables. It is worth ordering a set of spare panels with the machine.
Frequently Asked Questions
How does it differ from an ordinary vibrating screen?
A classic vibrating screen has a single vibrating mass and a rigid deck, which blinds on wet material. A flip flow screen has two vibrating masses and an elastic panel under alternating tension, which cleans itself. For dry material the ordinary vibrating screen is enough and cheaper. For wet material, the difference is between a machine that keeps running and one that stops every few hours.
When do I choose a flip flow screen over a star screen?
Both are designed for wet material. A star screen is better when you want a clean flat fraction, typically paper and cardboard, because flat material stays on top of the discs. A flip flow screen is better when moisture is high and the cut point has to be precise, because the opening geometry is defined rather than dependent on disc spacing.
How often are the screen panels replaced?
The elastic panels are wear parts, but they last longer than an equivalent rigid screen because their elasticity absorbs impact rather than taking it head on. The actual life depends on how abrasive the material is. They are replaced section by section, so the intervention stays local.
What is the machine's throughput?
No honest catalogue figure can be given, because the throughput of a flip flow screen depends heavily on material moisture and on the chosen cut point. The same machine can screen twice as much on dry material as on saturated material. We calculate it at configuration, from your real flow composition.
Is the equipment supplied new?
Yes. We supply new units only, made to order for your application, with complete technical documentation.
What maintenance does it need?
Checking the tension and condition of the elastic panels, inspecting the drive system and the bearings of the two vibrating masses, and verifying the counterweight setting. With no manual screen cleaning required, maintenance reduces to planned inspections.
Why URSTAG?
URSTAG is a premium brand of recycling equipment, with over 15 years of experience. You don't just get a machine, you get a solution engineered by specialists, built from top-tier components and backed by a team that supports you from design through commissioning.
• European engineering, every machine and every complete line is designed by our engineering teams in Europe, with a focus on reliability, safety and energy efficiency.
• Premium components, we build on motors and automation from industry leaders: Siemens, Schneider Electric, ABB, WEG, SEW-Eurodrive, NORD Drivesystems and Bonfiglioli.
• Over 15 years of experience, we know how materials and machines behave in real-world operation, and we configure each solution for your flow and volume.
• New equipment, configured for you, we supply new units, made to order for your application, with complete technical documentation.
• Delivery, installation and training included, we handle transport, commissioning and operator training, with support throughout the equipment's life.
As a premium brand, URSTAG relies on European engineering, top-tier components and experience. You choose a partner that supports your production long term, with equipment built to run reliably in demanding industrial environments.
