A woven bag washing machine is a coordinated recycling line for PP woven sacks, raffia bags and flexible intermediate bulk containers (FIBCs). It opens or cuts the feed, removes loose and embedded contamination, separates heavy material, dewaters the washed plastic and prepares it for extrusion. The correct line is determined by the actual bag construction and contamination—not by nominal throughput alone.
What material enters a woven bag washing line?
Typical feed includes fertilizer and feed sacks, rice bags, cement bags, industrial raffia packaging and used FIBCs. Although the woven substrate is often polypropylene, a used bag may also contain a PE inner liner, BOPP printed film, stitching, straps, labels, paper, metal, soil or product residue.
Identify these components before choosing equipment. A mono-material PP stream may be suitable for mechanical recycling after effective cleaning. Multilayer coatings, incompatible liners and hazardous residues can require source segregation or a different outlet. The CEFLEX design guidance for flexible packaging explains how construction and attached components affect polyolefin recycling.
Process flow from bags to clean regrind
| Pozornica | Glavni posao | What to confirm |
|---|---|---|
| Inspection and sorting | Remove unsuitable bags and large foreign objects | Previous contents, resin, liners, metal and moisture |
| Opening and size reduction | Cut compacted bags into a controlled, washable size | Feed form, rotor loading, screen or discharge size |
| Prewashing | Release loose sand, dust and product residue | Contamination load and water-loop capacity |
| Pranje trenjem | Scrub surfaces and transport material | Residence, wear, screen condition and rejected solids |
| Odvajanje po gustoći | Separate floating polyolefins from many heavy contaminants | Material pair, trapped air, flow and bottom discharge |
| Odvodnjavanje i sušenje | Remove free and surface water | Downstream moisture requirement and air handling |
| Densifying or pelletizing | Stabilize low-bulk-density feed and melt-filter the plastic | End-product specification and contaminant tolerance |
1. Inspect, sort and meter the feed
Start by defining acceptable and prohibited feed. Bags that held chemicals, pesticides or other controlled products need an appropriate risk assessment and disposal route; washing equipment does not by itself make an unknown residue safe. Remove metal hooks, stones and oversize objects before the cutting chamber.
A bale opener, conveyor or metering device should deliver an even load. Large surges cause unstable cutting, washing and drying. Record input mass and representative contamination samples so that later output tests can be tied to a known feed.
2. Choose shredding or wet granulation
Woven PP is light, strong and prone to wrapping. A shredder is useful for opening bulky bags and FIBCs, while a granulator can create a more controlled particle size. Some lines use both. Rotor geometry, knife clearance, screen choice and anti-wrapping provisions should match the feed trial.
Wet size reduction introduces water in the cutting chamber and can begin loosening dirt. Dry cutting simplifies that machine’s water circuit but transfers more contamination downstream. The right choice depends on abrasion, water management and the required flake size rather than a universal efficiency claim.
3. Remove soil, paper and product residue
Prewashing protects downstream equipment when bags carry sand or cement dust. A visokobrzinska frikciona pegla then applies mechanical scrubbing while a perforated screen releases water and fine contamination. Washer loading, rotor condition, screen openings and water quality influence the result.
Hot washing may be considered for a validated contaminant or adhesive, but it changes heating, chemistry, rinsing and wastewater requirements. Do not specify heat or detergent before testing the residue and confirming local discharge obligations.
4. Separate heavy contaminants
In a water-based tank, many unfilled PP and PE pieces float while stones, metal, glass and denser plastics sink. This is useful for removing a defined heavy fraction, but it does not reliably separate PP from a PE liner because both commonly float. Fillers, coatings and trapped air can also change behaviour.
Use the principles in our izmijenjeni vodič za razdvajanje sink-float to set feed rate, agitation, float removal and bottom discharge. Test both outlets: high float purity can hide excessive loss of usable PP to the sink fraction.
5. Dewater for the next process
Mechanical dewatering removes free water first. A centrifugal dryer, screw press or film squeezer may be used according to particle form and the downstream process. Thermal air drying can follow when the extruder or storage specification requires lower surface moisture.
There is no universal moisture percentage that is “ideal” for every woven-bag line. Set an acceptance limit with the pelletizer supplier or flake buyer, define the test method, and measure samples after stable operation. The film squeezing machine is one option for simultaneously removing water and increasing bulk density.
6. Prepare clean material for pelletizing
Washed woven material remains light and irregular. Buffer storage, a squeezer or an agglomerating stage can improve feeding consistency, but densification does not remove contamination. During extrusion, screen filtration removes certain solid contaminants; it cannot correct incompatible polymers, severe degradation or unsafe feed.
Define pellet requirements before purchasing the washing line: intended application, colour, ash, moisture, melt-flow range, odour, filtration and allowable contamination. These targets determine how much sorting, washing and drying is justified.
How to size and evaluate the line
Ask suppliers to state capacity on a defined feed and output basis. A nominal input rate is not the same as saleable dry output. Use a mass balance covering removed contamination, process loss, moisture and rejected material. Confirm that shredding, washing, water treatment, dewatering and pelletizing can all sustain the proposed rate.
For an acceptance test, agree on feed composition, run duration, sampling points and output limits before shipment. Record power, water makeup, labour, consumables and reject mass during the trial. These measured values are more useful for operating-cost planning than generic savings percentages.
Operating checks that protect quality
- Inspect incoming bags for resin, liners, previous contents and heavy objects.
- Track knife condition, screen wear and wrapping around rotating parts.
- Monitor washer load, water clarity, suspended solids and recirculation flow.
- Sample float and sink outputs as well as the final washed material.
- Trend moisture, ash or contamination against feed changes and operating settings.
- Follow documented lockout/tagout before clearing jams or servicing equipment.
The OSHA hazardous-energy guidance provides a baseline for energy-control procedures. Site-specific guarding, access and wastewater requirements must also be addressed.
Česta pitanja
Može jedan pralni niz procesuirati oboje PP vezane torbe i PE film?
Possibly, but only after trials. The materials can differ in thickness, wrapping behaviour, contamination and dewatering needs, and a mixed PP/PE output may not meet the intended buyer’s specification.
Razlikuje li sink-float tank torbe od polipropilena (PP) od linera od polietilena (PE)?
Nije pouzdan u vodi jer nenasjeni PP i PE često plavaju. Potrebno je izdvojiti po izvoru, kontrolirati dizajn vreća ili drugi potvrđeni metoda razdvajanja, kada se ova dva polimera moraju prodavati posebno.
Da li trebaju očišćene vezane torbe direktno ići u ekstruder?
Only when moisture, bulk density and contamination meet the extruder’s feed specification. A squeezer, agglomerator, buffer or additional drying stage may be required.
Specify the feed before requesting a line
Send Energycle representative bag samples, photographs of contamination, previous-use information, hourly input availability and the required flake or pellet specification. The PP woven bag and raffia recycling line can then be configured around verified material rather than a generic equipment list.
