Extrusion processing is a system that includes several unit functions such as blending, cooking food, kneading, shearing, forming. Extruder machines are categorized based on the way of operation (cold extruders or hot extruders) and the way of structure (single-screw extruders or double-screw extruders).
The methods of operation are the same in most types: the ingredient are given into the extruder drum and the screws then move the ingredients along with them. Further along the drum, scaled-down flights limit the volume and enhance the resistance to motion of the ingredients. Consequently, they fill the drum and the gaps between the screw and gets to be compacted. While they go further along the drum, the screw kneads the ingrediens into a semi-solid, plasticised bulk. When the ingredient is heated up over 100oC the course of action is called extrusion cooking.Here, frictional heat and any kind of extra heat would result in the temperature to go up quickly. The cooking ingredient is then gone by the part of the barrel with the tiniest flights, in which stress and shearing is definitely further enhanced. Lastly, it will be pressured via one or two restricted dies at the release ending of the drum.
When the cooking ingredient comes out under stress from the die, it expands to the last appearance and cools down quickly while wetness will be flashed away as vapor. A number of shapes, such as rods, balls, doughnuts, pipes, strips or shells will be shaped. Standard products feature a broad variety of small density, puffed snackfoods and ready-to-eat extruded cereals.Extrusion products could be eventually processed deeper by means of drying out , frying or packing . Numerous extrusion foods can also be ideal for covering .
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