Two-Stage Twin Screw & Single Screw Compounding Extruder

• Applicable Products: PVC cable material, sole material, clarity bolt material, medical material;Low-smoke and no-halogen material or Low- halogen and flame retardant material; EVA screen material, PE and EVA masterbatch, etc.
• Applicable Processing:Compounding,Pelletizing
• Alias: Two-stage Twin screw & single screw extrusion line, Double stage twin screw & single screw extruder, compounding extruder

SJS Series Two-stage Twin Screw & Single Screw Extruders are very suitable for PVC compounding and pelletizing.

Whatever single screw or twin screw extruder, for ordinary use, materials from feeding to extruding, all need the steps: solid conveying, melting, compounding, degassing and extruding etc. Normally, different step requires different screw structure, different operating conditions, such as the RPM, barrel heating temperature, material pressure, etc.

For single screw extruder extruding, we can provide different screw structure to each step, also can set different temperature for different step, but because all these extruding steps finished on the same screw shaft that means the screw rotary speed is the same, each step temperatures must influence each other step. All these cause pressure building-up, energy inputing can not carry out according to individual step requirement. So for the best extruding scheme, because of above facts, it doesn't work.

For example, to increase the output of single screw extruder, for conveying step, we’d better choose the screw structure like this: deeper groove depth, longer screw distance, higher RPM, lower die pressure and lower extruding temperature, etc. But if so, the melting step must be influenced. Higher RPM means the conveying speed would be faster, so it would influence the melting effect. Sometimes for better mixing, we use the kneading elements, it not only provides better compounding also high temperature. If the materials with the character of temperature sensitive, this kneading element may cause materials degraded.

For twin screw extruder extruding, the steps also include solid conveying, melting, conveying, compounding and degassing etc, so conflicts and influences also exist.

To solve these problems, people put forward the concept: Two-stage Twin Screw & Single Screw Extruder, put the extruding steps on two extruders. First stage is high speed co-rotating twin screw extruder, mainly for materials melting and compounding;Second stage is low speed single screw extruder, for pressure building-up and extruding, etc.

The twin screw extruder without die head can avoid the high temperature due to back pressure come from die head during processing, so the compounding can be finished as enough as possible in the twin screw but do not worry about the high temperature which may caused the PVC decomposing. And the compound melt of the PVC material will fall into the big size single screw extruder for cooling, pressure creating and filting because the big size screen changer is equipped on the single screw extruder, then the compounded PVC material will be extruded out from the die and be cutted with rotating knife into small pellets(granules), air cooling pelletizing system is the best choice for the PVC material especially good for the PVC compound of cable grade. The finished pellets (granules) will be cooled and tranferred by air to the silo for storaging and preparing for the packing.

For output lower than 1000kg/hr
> Pre-mixing
> Feeding
> Twin screw compounding and single screw extrusion
> Pelletizing (Dry cutting with air cooling)
> Cooling and collection for packing

For output higher than 1000kg/hr, the max output can be 3000 kg/hr
> Raw material supplying and loading
> Weighing and dosing according to the process program
> Pre-mixing and cooling
> Feeding
> Twin screw compounding and single screw extrusion
> Pelletizing (Dry cutting with air cooling)
> Cooling and collection for packing

Audop supplies all the two stage twin screw & single screw extruders and corresponding auxiliary machines or systems to meet your business demands. You get the freedom to build your extrusion line around the system components that meet your exact requirements. All subsystem and support equipment such as feeding device, dies, control panels, etc may be included to provide a total system concept. The end result is superior quality, highly reliable machines that turn products into bigger profits for you.

While the above may sound similar to other suppliers, we can assure you that the specific execution that we utilize is dramatically better. Upon request we can provide further specifics of our unique and proprietary approaches, on-going continuous improvements.

Technical Parameters

Your requirements are the basis for our development and a daily challenge to bring to fruition, please do not hesitate to inquiry us.