Plastic Film Recycling Washing Line

Working Principle: A Step-by-Step Guide

The entire plastic film washing line is intelligently controlled via a central electric control panel and cabinet, ensuring synchronised operation. Each piece of equipment is seamlessly connected using conveyors for smooth material flow.

1. Plastic Shredder Machine:

   As long pieces of plastic film (similar to cling film) can easily tangle and cause blockages in conveyors and rotary-based machines, the initial crucial step is to cut the film into smaller, more manageable pieces using a robust plastic shredder. The resulting plastic pieces from the shredder are typically around 1-5 inches (2.5-12.5 cm).

2. Plastic Granulator (Wet Grinding):

   The plastic granulator further reduces the size of the plastic film into even smaller pieces, approximately 10-20mm. With water constantly injected into the cutting chamber, our wet granulation process also serves as a “pre-treatment,” partially cleaning the plastic film before it moves to the next stage.

3. Friction Washer:

   A high-power washing unit, our cold-water friction washers spin at nearly 1,000 rotations per minute. As the PP/PE films enter the friction washer, they rub against each other at high speeds, effectively dislodging hard-to-remove contamination. Simultaneously, any paper and cardboard are broken down into fibres and removed. While one friction washer is standard, various washing plants have requested a secondary friction washer to ensure exceptional cleanliness.

4. Sink-Float Separation Tank:

   Using water as a medium, materials that float are separated from those that sink. In plastic film recycling, PP and PE films will float, while heavier contaminants such as dirt, sand, glass, metals, and other plastics will sink. A screw conveyor at the bottom of the sink-float separation tank removes these contaminants. Beyond separation, this apparatus also serves to further clean the plastic film.

5. Centrifugal Dewatering Machine:

   The first stage in the drying process, our centrifugal dewatering machine, employs centrifugal force to remove a significant portion of water from the plastic film before it proceeds to the thermal dryers. As thermal dryers use heat to evaporate water, they require more energy. Hence, the use of the dewatering machine is highly beneficial in saving long-term operational costs.

6. Screw Press Dewatering Machine (Optional):

   An optional piece of equipment, the screw-press dewatering machine is a more advanced version of the standard dewatering machine. Instead of using centrifugal force, the screw press squeezes water out via high pressure. This machine can, in some configurations, replace both the centrifugal dewatering machine and thermal dryers.

7. Thermal Dryer + Cyclone Separator:

   The clean plastic film is vacuumed from the dewatering machine into the thermal dryer system, where it travels down a series of stainless steel tubes, mixing with hot air. Remaining moisture is thoroughly dehydrated in this process, which culminates with a cyclone separator. The cyclone separator allows the plastic film to mix with a fresh stream of cool air, preparing it for storage in the product silo. It is also effective in removing fines and dust particles.

8. Product Silo:

   A dedicated storage tank for the clean, dry pieces of plastic film, ready for the final processing stage or sale.

9. Plastic Pelletising Machine:

   The final, and arguably most crucial, step in plastic film recycling is processing the clean film into plastic pellets before it can be reused in production. To achieve this, we offer a specialised plastic film water-ring pelletising system that produces uniform, high-quality round plastic pellets.