Views: 13 Author: Site Editor Publish Time: 2022-04-14 Origin: Site
Most recycling tasks use pellets as an intermediate product. For some materials, a plastic recycling twin-screw extruder can be followed by a pellet cutting system or downstream flake extrusion. In the case of PET bottle flake recycling, it can produce PET pellets or directly manufacture PET flakes. Twin-screw extruders are developed on the basis of single-screw extruders, which have numerous advantages that cannot be ignored compared to single-screw extruders.
Here is the list of contents
Introduction of reverse rotary twin-screw extruder
Advantages of plastic recycling twin-screw extruder compared with a single-screw extruder
Plastic recycling twin-screw extruder process
Advantages of Roots Pumps
Reverse rotary twin-screw extruders are widely used for extrusion molding and batch pelletizing. Close-meshed counter-rotating twin-screw extruders for PVC profile extrusion are limited to a shear rate of [γ] = 6 to 8 S-1. The maximum linear speed of the screw is V = 7 to 8 m/min. The maximum linear speed of the screw for PVC pipe extrusion is V = 10 to 12 m/min. Therefore, it often operates at a lower speed.
Engaging co-rotating twin-screw extruder, widely used for polymer modification: blending, filling and fiber reinforcement, compounding, or mixing. It can also be used for the extrusion of molded products but is rarely used to process profile products. The allowable shear rate is about [γ] = 60 to 140 S-1.
Screw linear speed V = 30 to 50 m/min, with a maximum linear speed of V = 160 m/min. High-speed meshing co-rotating twin-screw extruder compounding, extrusion, and venting operations are a continuous chemical reaction, and this extrusion speed is in the range of 300 to 600 r/min.
Higher production capacity.
Energy and time savings due to the elimination of pre-drying and crystallization.
Superior quality of the final product, which does not turn yellow.
High flexibility, because the plastic recycling twin-screw extruder has good self-cleaning properties and can change formulation and color very quickly.
Simpler logistics, because the new product in granular form and the different recycled products can be processed together.
Depending on the cleanliness of the raw material and the actual production needs, the twin-screw extruder for plastic recycling can be selected from water ring pelletizing or strip pelletizing to match the different raw materials. The production process of plastic recycling twin-screw extruders is rough as follows.
PET raw material feeding
TSE series plastic recycling twin-screw extruder
Degassing
Roots pump and specially designed filter
Specially designed water bath
Blower
Strip Pulping Machine
The most important feature of the plastic recycling twin-screw extruder lies in its use of a Roots pump and a specially designed filter. Compared to other types of vacuum pumps, the Roots vacuum pump has the following advantages.
No gas compression in the pump chamber and clearance between the moving parts, so they are insensitive to dust and vapors in the pumped gas and can pump out condensable vapors.
The moving parts in the pump cavity do not need oil lubrication, which can avoid the pollution of the vacuum system by oil vapor and is conducive to obtaining an oil-free vacuum.
The utility model product has a simple structure, low noise, no contact of moving parts in the pump cavity, no damage, and low maintenance cost.
It starts quickly and reaches the ultimate vacuum in a short time.
Nanjing Haisi Extrusion Equipment Co., Ltd. is a high-tech enterprise consisting of a team with many years of experience in R&D, design, manufacturing technology, sales, and service in the extruder industry. If you are interested in our products, welcome to contact us!