A floating fish feed extrusion process that can convert any amount of raw materials into intermediate or final products with high consumer appeal under high temperature and pressure. This application not only improves the palatability and nutrient digestibility of the food but also makes the feed pellets more stable and easy to store. Extrusion provides a way to combine a range of ingredients into a product that floats, remains stable in water, and can float in water for 12 hours without breaking down. Nowadays, fish feed extruder machines used to process feeds falls into two categories: single screw fish feed extruder and twin screw fish feed extruder.
The belt conveying method is generally used for single-screw extruders, and the spindle speed is fixed and cannot be changed. The shaft connecting the screw components of various structures constitutes the screw of a single screw extruder. The feeding part, the kneading part (or melting part) and the forming part make up the whole screw. After the material enters the barrel from the feeding port, it undergoes the solid conveying and melting process in the screw, and changes from a loose state to a continuous dough.
The mainline of the material is to generate two C-shaped material flows along the inner wall of the sleeve in the direction of the screw rotation. The other is to form a countercurrent via the clearance of the screw’s meshing section. The material is “∞”shaped forward as a result of the left screw pulling it into the meshing gap and the right screw pulling it out of the gap. This causes the screw edge to produce forward transmission as well as to allow the material to change direction, which ultimately creates a different rotation mode for the twin screw.
1) Twin screw extruders have great mixing capacity thanks to intermeshing screws and a wide range of dedicated screw designs that allow fine control over the degree of mixing. On the other hand, single-screw extruders have very limited mixing capabilities, and the flow restriction of mixing has to be enhanced by special screw designs.
2) The twin-screw extruder can handle a high degree of process flexibility and the ability to handle various processes such as melting, mixing, cooking, venting, cooling, etc. But for single-screw extruders, throughput and screw speed are limited.
3) Twin screw extruders are more productive than single screw extruders in terms of process output.
4) Compared to single screw extruders, which have basic structures and are less expensive, twin screw extruders are more expensive because of the complexity of the equipment.
5) The twin screw extruder’s plasticizing capacity is better and faster. Granular materials linger in the extruder for a longer period of time with single screw extruders, slowing down production.
6) Compared to a single screw extruder, which is easy to manipulate and has a straightforward control process, a twin screw extruder has a complex operation and greater process control needs.