MACHINERY | RECYCLING AND GRANULATORS
Answers to common recycling problems
Characteristics of waste plastic – such as feeding instability – can lead to recycling problems. In many cases, these problems can be solved with a minimum of effort, says Resul Gokpi- nar, international sales and marketing specialist at machinery supplier Polystar. Feeding instability: For maximum
productivity, feeding waste materials into plastic recycling machines must be stable. Excess or insufficient feeding can lead to poor production efficiency. Solution: Automatic material feeding systems with a belt conveyor, screw conveyor or nip roller feeders that work synchronously with a plastic pelletiser can provide stable feeding. Material contamination: Food
residues, dirt and other impurities – or mixing different plastics – can con- taminate the stream and cut quality
and reusability. It also makes the recycling process less efficient. Solution: The easiest solution is to ensure that waste plastics are clean and properly sorted before being recycled. Dirty plastic waste must be washed and dried beforehand. Blockages and hopper bridging:
Material blockage is usually caused by poorly prepared materials or poor
operation while requiring little input from opera- tors. Smart Control is generally available for all models and sizes of Hellweg system.
Cutting design At Plast 2023,CMG of Italy presented the EV916 and EV616 models from its Evoluzione range of post-consumer waste granulators. They are suitable for critical operating conditions – including wet or dry granulation – with a capacity 2,000-5,000 kg/h. The company has introduced a new cutting chamber design for the Evoluzione series. A new rotor configuration allows the blades to cut plastic feedstock perpendicularly against the bed blades, obtaining high cutting penetration and precision. The blades are mounted on the edge of the rotor holding modules and not on a holding block. CMG says: “The rotation of the rotor does not
produce the detrimental ‘drag’ effect,” said the company. “This means the mass of material being ground in the cutting chamber does not rotate with the rotor to produce lots of dust and fine particles – which will all become waste through the washing line.” Production of fine particles is reduced to few
percentage points, compared to a typical 15% or more from conventional granulators. The rotor is an open-type design and occupies only 30% of the cutting chamber volume. This
22 FILM & SHEET EXTRUSION | October 2023
maintenance of components. Solu- tion: Correct preparation – based on type, shape and condition of waste material, and using auto-feeding systems – can solve many material blockage problems. Periodic mainte- nance – such as changing filter meshes regularly and unclogging the die head – is also helpful. Overheating: Overheating of plastic waste in integrated pre-condi- tioning equipment, or overcooking the melt in the extruder, can degrade pellets and weaken end product quality. Solution: Setting the correct temperature in each section of a recycling machine – and using reliable components that do not cause temperature imbalance – can prevent overheating. Preventing material blockages also reduces local clogging and overheating.
feature alone allows twice the quantity of material in the cutting chamber, says CMG. The new cutting chamber has the so-called ‘tangential set up’. CMG has also introduced the G26 granulator
line, for use with extrusion, injection moulding and blow moulding. There are three models: G26-30, G26-45 and G26-60. The standard configurations cover capacities from 50 kg/h up to 300 kg/h. The line features integral sound enclosure and an innovative feed hopper design to accommodate a wide variety of shapes and dimensions of the parts to be ground. CMG says all models operate with high-efficiency, are equipped with EISA premium- efficiency motors and can have Adaptive Motor Power (AMP) controls.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.nexamchemical.com �
www.republicservices.com �
www.ravago.com �
www.repsol.com �
www.signode.com �
www.colines.it �
www.hosokawa-alpine.com �
www.rapidgranulator.com �
www.hellweg-maschinenbau.de �
www.herbold.com �
www.cmg-granulators.com �
www.polystarco.com
www.filmandsheet.com
IMAGE: POLYSTAR
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