—Single screw extruder: suitable for processing various raw materials and common livestock and poultry compound feeds.

     —Twin-screw extruder: The final product requires compound feed (aquatic feed,pet food) and high value-added raw materials (ɑ starch, textured protein), etc. It should be noted that the above divisions are not absolute. For example, we propose

It is proposed to use twin-screws to produce aquatic feeds, but currently many companies use single-screws to produce aquatic feeds.

There have been many articles introducing the differences between the two for aquatic feed production. In short, twin-screws have the following advantages over single-screws:

     —High yield rate, up to 98% or higher.

     —The particles are well formed and the particle shape is uniform. The twin-screw extrusion pressure is very stable, ensuring consistent particle molding.

     —The unique strong pumping capacity of the twin screws ensures no back spray or clogging. After stressing the quality, the steam content in the material is relatively high. Single-screws are prone to steam overflow and back-injection in the feeding area, resulting in unstable material flow and blockage of the machine. However, similar situations will not occur with twin-screws.

     —Can continuously and stably produce various small particle products. When producing particles with a diameter of 2 mm and below, the single screw working condition is unstable, the output rate will drop sharply, and the material type will also deteriorate.

     —Density control is more stable and reliable. The material is melted more fully and evenly in the twin-screw barrel, and the production of floating materials, sinking materials and slow-sinking products can be accurately controlled.

     —It has wide adaptability to formulas and is more suitable for high-energy formula production. Twin-screws can produce high-energy formulas with a fat content of 11~13% (foreign data say it can reach 17%), while single-screws generally do not exceed 6~8%.

     —Easy to operate and stable production process.

It is precisely because of the many advantages of twin-screw extruders compared to single-screw extruders in the production of aquatic feeds that we recommend giving priority to twin-screw extruders when producing this type of products. Of course, the investment and production costs of twin-screws are much higher than those of single-screws, and should be considered based on actual conditions.