Differences between single-screw extruder and twin-screw extruder

Single-screw extruder: suitable for single materials and general livestock and poultry feed, with incomplete gelatinization. Twin-screw extruder: produces well-formed products with an attractive appearance, uniform and high degree of gelatinization, density-adjustable feed (aquatic feed, pet food), and high-value-added materials (ɑ-starch, textured protein). It should be noted that the above differences are not absolute; for example, twin-screw extruders are recommended for aquatic feed production, but many companies currently use single-screw extruders for aquatic feed. Many articles discuss the differences between the two in aquatic feed production. The twin-screw extruder has the following advantages over the single-screw extruder:

1. High yield rate, up to 98% or more.

2. Good pellet formation, uniform pellets, stable die pressure of the twin-screw extruder ensures uniform pellet formation.

3. The twin-screw extruder ensures no backflow or clogging. After intensive conditioning, materials with high steam content are prone to steam overflow and backflow in the feed zone of a single-screw extruder, causing unstable material flow and clogging, whereas the twin-screw extruder generally does not experience such issues.

4. Capable of continuously and uniformly producing various small pellet products. When producing pellets with a diameter of less than 2mm, the unstable working conditions of a single-screw extruder can lead to a sharp drop in yield and deterioration of product shape.

5. Product density control is more stable. The raw materials are more diverse, and even in twin-screw pumps, the production of floating, sinking, and slow-setting products can be precisely controlled.

6. Twin-screw extruders can handle more complex raw material formulations. In terms of product fat content, single-screw and twin-screw extruders show more significant differences.

7. Twin-screw extruders are easier to operate, and the production process is more stable.

In summary, twin-screw extruders have more advantages in producing aquatic feed, and the products are more easily digested and absorbed by consumers. Therefore, after considering customer needs, we generally recommend twin-screw extruders.