Introduction on Extruding Principle

Firstly, the materials prepared and pulverized enter the feeding bin for bridge-breaking and are to be processed. When working, the feeder of the extruder continuously feeds the material in bridge-breaking feeding bin to the different diameter cylinder conditioner for conditioning, adds evenly, the continuous and metered steam, water and other liquids into conditioner while material is entering into it.

The material being conditioned for a certain period enters the feeding section of the extruding assembly for extruding, the material is conveyed from the feeding section, and the feeding section on the extruding machinery is mainly used for conveying the material to kneading section and primarily compressing the material; in the kneading section, the material will be gradually ripened or dissolved through strong stirring, mixing and cutting; the pressure and temperature will rise gradually after entering the final ripening section, and the material will be ripened further, the starch will be gelatinized further, the fat and protein will be modified and homogenized to form a non-crystal texture; finally, the material will be extruded and cut into shapes through the discharging assembly.

Three sections of extruding assembly can be adjusted as required by the production. The screw conveys the material to the whole expanding chamber, the mechanical energy of rotating screw will be transformed as heat energy through abrasion between material and parts of the extruder as well as internal abrasion of material. The rotating speed of the extruding screw is adjustable, and therefore, it is possible to adjust the extruding effect during the process according to processing requirement, so as to control the product density and ripeness.

When material is extruded to pass through the die holes in the end of the extruding machine chamber, doughy material will be processed to a certain shape. Because of the great push and mix of screw in the machine chamber, a certain pressure and temperature will be formed in material, so that the material will expand greatly when extruded from the die holes or when most of water is evaporated momentarily or lightly expanded because less water is lost. This can be realized through strictly control each operation parameter as required.

During production, material will be greatly expanded and kept in a corresponding shape and dimension depending on structural features of material.