The Twin Screw Extrusion (TSE) process , enables the continuous production of highly homogeneous and finely structured products, using bio-sourced or synthetic raw materials. It is used to produce a wide range of Food & Feed products, Cellulose pulps, Bio-sourced plastics and chemicals.
HOW DOES EXTRUSION WORK?
Extrusion processing aims to physico-chemically transform continuously viscous polymeric media and produce high quality structured products thanks to the accurate control of processing conditions.
Twin screw extruders consist of two intermeshing, co-rotating screws mounted on splined shafts in a closed barrel. Due to a wide range of screw and barrel designs, various screw profiles and process functions can be set up according to process requirements. Hence, a twin screw extruder is able to ensure transporting, compressing, mixing, cooking, shearing, heating, cooling, pumping, shaping, etc. with high level of flexibility. The major advantage of intermeshing co-rotating twin screw extruders is their remarkable mixing capability which confers exceptional characteristics to extruded products and adds significant value to processing units.
In twin screw extrusion processing, the raw materials may be solids (powders, granulates, flours), liquids, slurries, and possibly gases. Extruded products are plastics compounds, chemically modified polymers, textured food and feed products, cellulose pulps, etc.
Difference between single screw and double screw Extruder
Compared to single screw extruder, double screw extruder has below features:
1) Material flow is stable, uneasy happen cutoff or billow, productive process is reliable.
2) Most heat of double screw extruder mainly come from mechanical transformation during operation, small amount of heat comes from the heating jacket. The single screw extruder often require additional equipment preheat quenched materials.
3) Time distribution is relatively narrow range of material retained in the machine, which is easier to control the temperature of the material, sufficient energy utilization, yield and quality are very stable.
4) Double screw extruder has a screw surface self-cleaning effect, so that the transportation of materials is stable, little residual material in cavity when finish working, and no need stop to cleaning if change the production material.
5) Double screw extruder has large productivity, is appropriate for processing of materials containing high oil (> 17%) and high humidity of materials (more than 30% moisture content)
Double screw extruder has complex structure, request high precision machining, therefore, investment for production facilities is much greater if select this type, so whether select it according to the actual situation.