Working Principle of Twin Screw Puffing Machine
Twin-screw puffing machine is the two intermeshing and the same direction of rotation of a pair of screws, which together play a role in conveying, friction extrusion and heating, relying on the principle of positive displacement of the input material, forcible conveying, and seldom form a pressure reflux, which is a better solution to the single-screw extrusion puffing machine on the problem in this regard, strong conveying. According to the function and screw arrangement, the screw is divided into three sections: material conveying section, ripening and melting section, uniform molding section.
The material enters into the barrel through the inlet, and with the rotation of the twin screw, it is conveyed forward along the direction of the thread to mix the ingredients thoroughly. According to the process and technical requirements, it can be added directly into the barrel through the liquid injection port of the second section of the barrel. In this section, the material is processed into a continuous dough by the action of the twin screw.
After entering the maturing and melting section, the thread structure changes, the pressure rises, coupled with the external heating of the barrel and the shearing of the material between the screws and between the screws and the barrel, the temperature of the material rises, and it begins to melt until it is all molten. Thread gap is further reduced, the material temperature and pressure rise, the starch in the raw material is fully pasted, fat, protein denaturation, further homogenization of the organization, to reach the homogeneous forming section.
Material flow through the manifold evenly divided into molds, at this time the pressure is usually 3 ~ 6Mpa, the temperature can reach 150 ~ 200 ℃, the high pressure in the closed barrel exceeds the saturated vapor pressure at the extrusion temperature, the water will not evaporate quickly, when the material is extruded from the mold holes, the pressure is quickly released, free water evaporates dramatically, the material expands, the water from the material is rapidly dispersed, the product is quickly cooled to about 80 ℃, is cured and shaped, the product is cured and shaped. The product is quickly cooled down to about 80℃, cured and fixed, and maintains its shape after expansion.
Twin-screw extruder combines compression, mixing, blending, shearing, melting, sterilizing, puffing, molding and other functions into one, and all of them are completed in a very short period of time. The change of molds can change the shape and size of the products, twin-screw extruder can produce a wide variety of production line food, can produce casual snack foods, breakfast cereals, sandwich puffed food, instant rice noodles, soups, slices of bread, organized vegetable proteins, confectionery, seasoning components, pet food, fish and shrimp feed, etc., and can be developed into countless kinds of new food.
