Precision screening, 40–200 µm
Fine stainless sieve mesh removes solids before they dissolve, protecting downstream pumps and the biofilter with stable separation and clog resistance.
Automatic Rotary Drum Filter
The first line of defense in any RAS — a fully-automatic microscreen drum filter that removes suspended solids, uneaten feed, algae and faeces down to 40–200 µm before they break down and load the biofilter, with gravity-fed flow and high-pressure backwash for 24/7 unmanned operation.
- Capacity5–200 m³/h
- Mesh40–200 µm selectable
- Screen304 / 316L stainless steel
- WaterFresh & saltwater
ISO 9001 CE OEM / ODM
15+ years in aquaculture engineering · Trusted by Japfa Group, Japan Nissui & Tropo Farms · Shipped worldwide in one container
Product Description
Automatic rotary drum filter made of case part, drum components, back washing system, motor control case, which made up of nontoxic corrosion-resistant engineering plastics. We use 316L stainless steel 100–400 mesh filter screen imported from Germany to separate suspended solids from water.
Advantage:
★Multiple working modes: Auto, Stop, and Manual. When in Auto working mode, it can automatically turn on and off
the backwashing system. It also can base on the mesh’s blocking situation to set the backwashing time.
★Use high-quality and special woven stainless steel mesh. A small aperture, low resistance, and strong flow capacity.
★Outer shell made of high-quality PP material, strong corrosion resistance, and durable
★Internal dump tank designed in tilted, flushing sewage can flow out easily.
★Transparent cover made of thicker anti-throw material. Can view the running state at any time.
Application
Package and Shipment
Specifications
Models & configuration
Model series integrated from the standard industry range — final specifications are confirmed by SIGMA's production line per project.
| Model | Capacity | Typical use | Core configuration |
|---|---|---|---|
| SIGMA-RDF-5 | 5 m³/h (≈1,320 GPH) | ||
| SIGMA-RDF-10 | 10 m³/h (≈2,640 GPH) | ||
| SIGMA-RDF-20 | 20 m³/h | ||
| SIGMA-RDF-30 | 25–30 m³/h | ||
| SIGMA-RDF-50 | 50 m³/h (≈13,200 GPH) | ||
| SIGMA-RDF-100 | 100 m³/h (≈26,400 GPH) | ||
| SIGMA-RDF-200 | 200 m³/h |
| Filtration precision | 40 / 50 / 70 / 100 / 120 / 200 µm mesh options (70 µm typical) |
|---|---|
| Screen & drum | 304 / 316L stainless-steel sieve mesh (316L wedge-wire on largest models) |
| Housing | Food-grade PP / SS304 / SS316 (316L for saltwater) |
| Water feed | Gravity flow preferred (low head loss, energy-saving) or pump feed |
| Self-cleaning | Differential-pressure or timer triggered, high-pressure spray-nozzle backwash to sludge tray |
| Water type | Freshwater / saltwater |
| Options | UV port reservation, VFD, PLC integration, enlarged sludge collection |
System composition
High-pressure self-cleaning nozzles
Fan-pattern spray nozzles flush the mesh from outside on every cycle, keeping the screen clear and throughput high — no manual cleaning.
Fully automatic, 24/7 unmanned
Backwash is triggered by differential water level or a timer, so the drum filter for RAS runs unattended at very low operating cost.
Gravity-fed, low energy
Low head loss allows pure gravity flow or pump feed, cutting pumping energy across the recirculating loop.
316L corrosion resistance
Suited to seawater RAS and abrasive duty; mesh and drum are 316/304 stainless steel.
Modular and expandable
Multiple drums combine for larger farms — flexible installation and easy capacity upgrades.
Low maintenance
Few moving parts and few failure points; periodic inspection is all that is required.
Application
- First-stage solids removal in RAS for tilapia, sturgeon, trout, shrimp and hatchery duty
- Koi and ornamental-fish display ponds
- Seawater aquaculture and recirculating-water pre-treatment
- Municipal / industrial wastewater primary screening and process-water reuse
Video
Automatic Rotary Drum Filter
FAQ
Frequently asked questions
How does a rotary drum filter work?
Water enters the rotating drum and passes outward through a fine stainless-steel sieve mesh, trapping solids on the inside. As debris builds up (or on a timer) the drum turns and a row of high-pressure spray nozzles flushes the mesh into a sludge tray — fully automatic, with no manual cleaning.
What micron rating does the drum filter use?
Filtration precision is set by the mesh, commonly 40–200 µm, so the unit can be tuned from fish RAS to shrimp or hatchery duty.
Why is a drum filter the first stage in a RAS?
Removing solids is the first critical step — if suspended particles, uneaten feed, algae and waste are not taken out early, they dissolve, spike ammonia and overload every downstream stage.
Can the drum filter be used in saltwater RAS?
Yes — the mesh and drum are 316/304 stainless steel and the housing is food-grade PP or stainless steel, both built for fresh- and sea-water. Units run by gravity feed or pump feed.
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