Difference Between Dry And Wet type Fish Feed Extruder

There are two types of fish feed extruders. One is the dry type fish food extruder. The other is the wet type fish food extruder. Both need to be used in conjunction with the steam boiler to produce steam for pelletizing. Both are used widely by pets such as fish, catfish and shrimp. It is important to understand the functions of fish feed extruders.

Dry Type Fish Feed Extruder
Wet Type Fish Feed Extruder

Differentiation between dry and wet fish feed extruders

  • Wet types have a higher capacity than dry ones. For example, a 15kw pellet mill can produce 120-150kg/hour of dry type, while 180-200kg/hour is the capacity of the wet type.
  • Wet types are more expensive than dry.
  • They are nearly identical in terms of digestibility. Although the surface of pellets made from wet type is slightly better than that of dry, it doesn’t make a huge difference.
  • Conditioner is available for wet-type floating fish feed pellet mills. To work with the conditioner, it will also require a boiler. Dry type machines do not require a boiler or conditioner. Both the dry and wet types of pellet mills can produce pellets from 0.9mm to 10mm in size.

What is a Dry Type Fish Feed Extruder and How Does It Work?

There are two types available for floating aqua feed making machines: the dry type fish feeder extruder and the wet type fish feeder extruder. The dry type fish extruder is used primarily for making aquatic feed such as fish feed pellets and tilapia feed, catfish food pellets, shrimp feed pellets and crab feed pellets. The heating plate of the dry-type fish feed machine heats the pellet feed at high temperatures.

Because they are puffed, the granules will float in the water for approximately 24 hours. The finished particle sizes are 0.9mm to 1.5mm to 2mm, 2.5mm to 3mm, 2.5mm to 3mm and 3.5mm to 4mm, 4.5mm to 5.5mm to 6mm etc. Upto a larger 15mm. Dry type machine heats the material using an electric heating plate. This dry type machine extrudes the material through the holes of a die under the action by the screw extruder. The machine releases the pellets and then the temperature and pressure drop dramatically. This causes the water to evaporate. The material is then expanded to form porous particles. The moisture content can range from 15% to 20% during this process.

Principle of Dry Type Fish Feed Extruder

When extrusion operation is performed, the material is moved from the open end to the extrusion cavities input by the screw transport to the entire cavity. The screw conveying action promotes material flow through the gap between the pressure rings and the inside cavity.

The material is extruded from the die hole at one end of the puffing cavities. This dough-like material is then processed into a specific shape. Due to the enormous propulsion of the screw in a puffing cavity of the dry fish feed machine, tremendous pressure is created. The material forms when it is extruded through the die hole. A large amount of water evaporates immediately, which significantly reduces its moisture content.

What is a Wet Type Fish Feed Extruder and How Does It Work?

The wet type fish feed extruder is widely used to make high-quality floating aquatic feed pellets. It is suitable for catfish, fish, shrimp, crabs, cats, dogs, and other pets. Wet type fish feeder machines can be used to make raw materials such as wheat, soybean, cake, and other scraps. The puffed particles that are produced by the fish feed extruder machine will float on the surface of the water for up to 24 hours without settling.

These machines are used mainly in large and medium-sized feed processing facilities and farms. It works in conjunction with the steam boiler. The boiler can continuously supply hot steam to extrude the wet type fish-feed machine extrusion section. The wet type machine works in the same way as the dry type fish feeder extruder machine. The wet type machine requires water or steam to raise the moisture level to twenty percent or more during processing. The steam raises the material’s temperature.

Working Principle Of Wet Type Fish Feed Extruder

The wet type fish feeder machine is made up of a screw, barrel and template. The barrel and screw are combined in sections. The compression degree can be adjusted to suit the requirements of the extruded food, as well as the expansion degree. The raw material is not heated once it reaches the filling device. Instead, the screw is pressurized at high temperature and pressure to cook and sterilize it.

The starch and fibers of the raw material expand during high-temperature curing. Under pressure-sealed conditions, the material is then moulded into pellets by using the molding die. The regular rotation of a screw generates high pressure, which is then cut using the regular high speed rotation of a front cutter. Finally, the product is shredded into puffed balls at room temperature and pressure.

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