The Difference Between Single Screw Extruder and Twin Screw Extruder

First of all, we take the production of aquatic feed as an example, according to the material and purpose of the expansion from the structure of the single screw extruder and twin screw extruder,

In general:

--- Single screw extruder: suitable for processing all kinds of raw materials and common livestock and poultry compound feed.

--- Twin-screw expander: The final product requires good molding and beautiful appearance, uniform maturation and adjustable density of compound feeds (aquatic food and pet food) and high value-added raw materials (alpha starches and histones), etc. It should be noted that the above division is not absolute. For example, we suggest using twin screw to produce aquatic feed, but there are many enterprises using single screw to produce aquatic feed. Many articles have introduced the differences between the two used in aquatic feed production. 

In short, compared with single screw, twin screw has the following advantages:

--- High yield, up to 98% or higher.

--- Good particle molding, uniform grain shape. Double screw die pressure is very stable, to ensure consistent particle forming.

--- The unique strong pumping capacity of the twin screw ensures no backflow and blockage. After emphasizing the quality, the steam content in the material is higher, the single screw in the feeding area is easy to overflow steam, reverse injection, resulting in unstable material flow blocking machine, and the twin screw will not occur similar situation.

--- Can continuously and stably produce a variety of small particle products. In the production of 2mm and below diameter particles, the single screw working condition is unstable, the production rate will drop, the material type will become worse.

--- Density control is more stable and reliable. The material in the twin screw barrel melting more fully, uniform, can precisely control the production of floating materials, sinking materials and slow sinking products.

--- Wide adaptability to formula, more suitable for high energy formula production. Double screw can produce fat content 11~13% (foreign data said up to 17%) of the high energy formula, and single screw generally does not exceed 6~8%.

--- Easy to operate, stable production process.

It is because of the advantages of twin screw compared with single screw in the production of aquatic feed, so we suggest that the twin screw extruder is preferred in the production of this kind of product. Of course, twin screw investment and production costs are much higher than single screw, according to the actual situation to consider.