EXTRUDER

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EXTRUDER
Motor
Die
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Clextral EVOLUM 53 Extruder
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Extruder
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Extruder development in the food industry

• Mid-1930s Single screw continuous pasta press
• Oil extraction
• Pet foods
• 1960s RTE cereals
• 1980s Aquatic feeds
• In 1998 Retail value of extruded products 3.62
  billion or 3.7 million tons of production

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Extruder Classification
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Heat Generation
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Basic extruder components
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SCREWS and SHAFTS
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Elements for generating screw profiles and
pressures
1/2 P -cut
3/4 P - cut
1/2 P - Rev
1/2 P - 6 units
1/2 P - 9 units
1/2 P
1/2 P - Rev
9 units
Twin-flight
6 units
0.75
units
Twin-flight
1.5 units
0.75
units
Twin-flight
Twin-flight
3/4 P
3/4 P - 9 units
3/4 P - 9 units
3/4 P - 6 units
3/4 P - cone
3/4 P - cone
4.5
units
Single-flight
9 units
9 units - cut
Twin-flight
Twin-flight
Twin-flight
1/1 P - 9 units
1/2 P - Rev
Disks 0.75 units
Twin-flight
Twin-flight
6 units
Cone-screw
Shaft Collar
Paddles 1 unit
Washer
Paddles 0.75 units
3 units
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D screw diameter h channel depth t pitch N
screw speed
e axial flight tip thickness n number of screw
threads, d clearance between flight tips and
barrel
f screw helix angle (a function of diameter and
pitch)
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Advantages of Extrusion Process

• Adaptability
• Product variety
• Energy efficiency
• Low cost
• Unique products
• Increased throughput
• Product quality
• Minimal waste
• Minimum labor
• Combine several steps in conventional process

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PROCESSING STEPS IN A EXTRUDER
Feeding zone
Mixing
Cooking
Transport
Transport
Compression zone
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Single screw extruder
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Twin screw extruder (Corotating)
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Twin screw extruder (Counterrotating)