Extrusion Line

Although twin-screw extruders are more complex and costly than their conventional single-screw counterparts, they possess several advantages. Twin-screw extruders are operational at very low feed moisture requiring minimum post-extrusion drying. In addition, they allow greater flexibility of operations to control product attributes by monitoring a desired time, temperature, and shear history for the processed material because of an additional independent variable such as: throughput, screw speed, moisture content, barrel temperature, residence time, etc..

Among all equipment and processes in Fôrtek, extrusion process is the essence in the research of modern food/feed technology. Therefore Fôrtek is equipped with Bühler twin screw extruder.

Bhler etruding line, <br />used just for research purposes
Bhler etruding line,
used just for research purposes Photo: Dejan Dragan Miladinovic
Machine Specification:

Twin screw Bühler BCTG 62 extruder. El.motor 45kW.
Maximum production capacity is 800kg/h for fish feed production.
Liquid system is integrated with the possibility of liquid addition directly in the extruders barrel or pre-conditioner (BCTC). Minimum dwell time in the pre-conditioner is 62 seconds and maximum residence time is 10 minutes. There is unique possibility to add online tree different liquids into the preconditioners chamber.

Bhler BCTC preconditioner
Bhler BCTC preconditioner Photo: Bhler

Dryer specification: Bühler Fluid-bed Dryer/Cooler OTW50 - 05TSR 2, 2004; Uzwil, Switzerland. Our OTW Dryer/Cooler has the cooling/drying area of 3,5m² where the perforated screen area is 0,5m².

Bhler OTW 50 cooler/dryer
Bhler OTW 50 cooler/dryer Photo: Bhler
Processing of bulk materials in a pulsating fluid bed In many industrial processes, it is
necessary to bring granular solids into intimate contact with gases.
One possibility is processing in a fluid bed, where an upward-directed
stream of gas causes a bed of granular solids to become fluidized.
Processes such as heating, cooling and drying can be performed with
advantage in a fluid bed.

The special characteristics of the process are:

• Continuous process
• Intimate intermixing
• Uniform temperature distribution
• Material is completely surrounded by flowing process gas
• Large exchange surface area
• Drying to low end moisture
• Favorable specific energy requirement
• Meets stringent environmental protection regulations
• Low-noise operation
• No vibrations


Mode of operation of the OTW The material is fed through the inlet
airlock to the processing zone. The hot or cold air is introduced from
below through the air intake chamber into the machine. A special perforated
bottom spreads it uniformly across the entire processing surface. A rotary
pulsator causes the air to pulsate vertically, fluidizing the material.
The retention time of the material is controlled on the basis of the air
velocity and the inclination of the perforated bottom.

Fôrtek can also offer a small scale research production with minimum output of 50kg/h. Small scale research production exclude the continuous preconditioning. Preconditioning can be done in the small batch with the twin shaft paddle mixer-conditioner.

Extruded Pet Food
Extruded Pet Food Photo: Dejan Miladinovic
Published 30. June 2014 - 13:18 - Updated 23. May 2017 - 19:43

Norwegian University of Life Sciences (NMBU)

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