company news about Do you know the difference between Dry Type Fish Feed Extruder and Wet Type Fish Feed Pellet Mill?

The dry-type small fish feed pellet making machine operates on the core principle of "mechanical frictional heat generation." It requires no additional water or steam, relying entirely on the high-intensity extrusion and shearing action between the screw and barrel to generate heat, raising the raw material temperature to 120-150℃, achieving starch gelatinization and protein denaturation. Its structural features include a barrel inner wall made of highly wear-resistant material, a steep screw design, and a small screw pitch, maximizing friction with the raw material. The equipment has no steam or water addition system, equipped only with simple feeding and temperature control modules, resulting in a relatively compact machine body. For example, dry extruders commonly used in the production of freeze-dried pet snacks control the intensity of frictional heat generation by adjusting the screw speed (250-300 r/min), ensuring full expansion of low-moisture raw materials (moisture content ≤10%).

The wet small fish feed maker machine operates on the principle of "external energy + moisture synergy." During the extrusion process, a steam injection or warm water addition system raises the moisture content of the raw material to 15%-25%, while the heat provided by the steam (in conjunction with mechanical friction) raises the material temperature to 100-130℃. Its core structure includes a steam generator and a moisture metering and addition device. The barrel is divided into preheating, humidification, and expansion sections, each with independently adjustable temperature and moisture content. The screw design is gentle with a large pitch, emphasizing the conveying and mixing of the raw material and reducing localized scorching caused by excessive friction. The wet extruder for producing grass carp floating feed precisely controls the amount of steam added (100-150 kg of steam per ton of raw material) to create a uniform porous structure in the feed, ensuring a water resistance time of over 40 minutes.

The core structural differences between the two types of equipment also lie in their temperature control systems: dry extruders rely on dual temperature control via screw speed and barrel cooling jacket to prevent overheating; wet extruders, on the other hand, use steam pressure and barrel heating module for coordinated temperature control, resulting in greater temperature stability. Understanding these principles and structural differences is fundamental to making the right choice.

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