What Is a Single Screw Pelletizer for PET Plastic Flakes?

An increasing number of PET bottle washing plants are being established to recover dirty, highly contaminated PET plastic bottles. Most of these plants typically sell the PET flakes they produce directly to PSF (polyester staple fiber) plants. Given the limited applications of PET flakes, many of our clients seek to expand their business by converting the clean PET flakes they generate into PET plastic pellets. Once PET is manufactured into pellets, they can be widely utilized in injection molding, profile production, plastic manufacturing such as the creation of plastic sheets, and much more.

Previously, double screw extruders were predominantly used in PET flakes pelletizing facilities, but for higher capacity, the investment cost for double screw extruders is excessively high due to their design. As a result, we have developed this new style single screw extruder pelletizing system. By harnessing the advantages of single screw extruders and combining it with our specially designed screw for PET flakes, we have managed to improve capacity by 20% while also consuming less power compared to an equivalent sized double screw extruder.

This innovative system can also maintain the ideal viscosity of PET without requiring a complex pre-crystallization dryer system. Based on our in-house testing, there is only a minor 0.02-0.03 dl/g viscosity reduction when producing PET pellets from flakes.

From the feeding system to the final product, ASG provides comprehensive system designs to meet all of your production needs. Expect a high-quality pelletizing system that fulfills all your requirements at a competitive price.

Working Principle

Feeding and Moisture Removal

The motor drives the conveyor belt and hauling device with automated controlled feeding speed. A metal detector can be added to the belt conveyor and can be integrated with the control system to alert and halt the system.

The compactor eliminates moisture from the PET flakes through high-speed rotation and friction. This is crucial as high moisture content in the material will reduce the IV.

Single Screw Extruder

The PET material is advanced forward by the screw’s rotation while simultaneously completing the compaction, melting, and homogenization processes. The screw is constructed from high-quality nitride steel (38CrMoAlA) and processed with nitride treatment to enhance its corrosion resistance and wear-resistance.

Barrel

The barrel is a component of the screw pair and is made from nitride steel with an inner surface treated with nitride to increase surface hardness and improve wear resistance. The energy produced by heaters is transmitted through the barrel to melt the plastic. Temperature sensors and cooling fans are installed within each heating zone.

Vacuum Degassing

Its purpose is to remove low molecular weight materials and any residual moisture from the melted PET plastic. The vacuum degassing system consists of a vacuum pump, vacuum chamber, filtering tank, pressure gauge, and pipelines. It utilizes a water ring vacuum pump which creates high negative pressure via water sealing, making it suitable for eliminating waste gas and moisture.

Plasticizing And Degassing

A specialized single-screw extruder gently melts the PET plastic material. Throughout the melting and plasticizing process, a double-zone vacuum degassing system effectively removes volatiles such as low molecular weight materials and moisture.

Melt Filtration

A single-plate / piston double-station or non-stop double-plate / piston four-station screen changer can be installed at the head of the extruder to provide significant filtration performance. The filtration technology requirements depend heavily on the quality of the input material as well as the application of the pellets.

Pelletizing

An underwater pelletizing system is the standard granulating method for PET flakes. Our system features a self-adjusting pelletizing head, resulting in the highest granulate quality possible.

Vibration Drying And Bagging Station

An advanced vibration sieve combined with a horizontal centrifugal dryer delivers high-performance dried pellets with low energy consumption. The final bagging station can be designed according to the height of the PP jumbo bags used.

Technical Specifications

Model	Motor Power	Output (kg/h)
CT-100	90KW	300
CT-130	132KW	600
CT-140	160KW	900
CT-160	250KW	1200

Additional Images

Inquiries

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