Industrial Feed Extruder Machine

The feed extruder is specialized equipment for processing feed and food raw materials through mechanical extrusion. It is primarily used in livestock and poultry feed, food extrusion, and vegetable oil pretreatment, covering the feed processing needs for aquaculture, poultry, and pets.

Compared to the wet extrusion process, the dry extrusion process eliminates the need for a feed conditioner and its associated steam boilers and pipelines. This results in a system that is safe, simple, requires lower investment, and offers broad applicability. The process involves a short heating time, minimizing damage to heat-sensitive nutrients, making it a highly promising full-price feed extrusion and pelleting technology.

For full-price pet feed, extrusion and pelleting can effectively gelatinize starch, denature proteins, eliminate and deactivate anti-nutritional factors, and neutralize harmful microorganisms. This significantly increases feed digestibility, improves hygiene standards, and extends shelf life.

Working Principle

The extruder features a screw and a screw sleeve designed for mixing and kneading. After raw materials enter the extrusion chamber, they are subjected to continuous extrusion, friction, and shearing between the screw and sleeve. The internal pressure rises rapidly up to 4 MPa, and the temperature increases up to 140°C.

Within 3 to 7 seconds of this rapid increase in temperature and pressure, the physical structure of the material undergoes significant changes: starch is further gelatinized, proteins are denatured, crude fibers are broken down, and harmful bacteria such as Salmonella are destroyed. As the high-temperature and high-pressure material exits the discharge die, the pressure drops instantaneously, causing partial moisture flash evaporation. Upon cooling, the expanded material forms a loose, porous structure, appearing as clumps, flakes, or coarse crumbs.

Equipment Structure

1. Feeder: Ensures uniform and stable feeding by adjusting the feed volume based on the rated current of the extrusion motor. Speed control is typically managed via an electromagnetic variable-speed motor or frequency inverter. A screw auger is commonly used at the hopper outlet to convey materials into the extrusion section.
2. Extrusion Chamber: Comprises the screw, screw sleeve, die plate, and locking ribs. Both the screw and sleeve are modular (assembled in segments), allowing operators to adjust the compression ratio to meet the specific expansion requirements of different feed types.
3. Extrusion Mechanism: Functionally divided into three sections:

• Feeding Section: Features a larger screw pitch to transport and compress the material, ensuring the screw flights are completely filled.
• Compression Section: The screw flights become progressively shallower along the material flow direction, systematically compressing the material.
• Extrusion Section: Features the shallowest flights and a gradually decreasing pitch. Extrusion pressure reaches 3.0-10 MPa, and temperatures reach 120-150°C. Due to these extreme conditions, the screw and sleeve in this section are highly susceptible to wear. The outlet is equipped with a die plate tailored with specific hole shapes for various feed requirements. When the material is extruded through the die into the atmosphere, the sudden drop in pressure and temperature causes rapid volumetric expansion, moisture evaporation, and solidification into the final extruded feed.

Product Features

• Utilizes a single-screw extrusion system capable of producing optimized sinking extruded feed by precisely controlling material moisture, screw speed, and barrel temperature.
• Higher moisture levels promote starch gelatinization and improve pellet water stability. However, excessive moisture (over 29%) reduces conveyance efficiency within the extruder, while insufficient moisture yields floating feed and lowers water stability.
• Screw speed significantly influences sinking feed production. The optimal operational speed is 150-190 r/min. Excessive speeds result in floating feed, whereas insufficient speeds decrease pellet gelatinization and water stability.
• Barrel temperature control is critical for sinking feed manufacturing. The curing zone must be cooled and maintained between 40-60°C. High temperatures generate floating feed, while low temperatures negatively impact gelatinization and water stability. Incorporating raw soybean meal into the formula offers slight improvements to water stability.

Technical Specifications

Application Areas

• Feed Processing: Essential for producing aquatic feed (starter and fry feed for fish and shrimp), pet food (dog and cat kibble), and specialized livestock/poultry feed.
• Food Industry: Utilized in manufacturing breakfast cereals, instant nutritional powders, and leisure snacks such as corn flakes and rice crackers.
• Raw Material Pretreatment: Extrudes grains (corn, soybeans, rice) to enhance processing characteristics. It is also used to detoxify or modify proteins in materials like urea and cottonseed meal, and to convert crop residues (corn and wheat stalks) into high-quality feed for ruminants, pigs, and geese.
• Other Industrial Uses: Applied in the production of commercial fishing bait, textured vegetable protein (TVP), and modified starch.