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Author
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Topic: Extrusion question
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Marilyn
Member Posts: 1
From:St Louis MO. USA
Registered: Mar 2003
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posted March 28, 2003 08:39 AM
   
I have been charged with the mission of looking into getting a lab size extruder for sugar confections applications. I am a little confused about the difference between co-extrusion and twin screw extruders. Do I need a twin screw extruder to do co-extrusion?? I want to be able to extrude filled tubes, cut shapes, etc. Can I use a single screw for this? Thanks for any insight you can give me.
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Tom C
Moderator Posts: 106
From:Wharton, NJ, USA
Registered: Jun 2001
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posted March 28, 2003 09:32 AM
You don't need a twin screw for co-extrusion, but you do need 2 extruders.Often twin screws are used for food extrusion because of low viscosity and the desire to keep all surfaces inside clean of hangup. Additionally twin screws can handle moisture and mixing problems better than single screws. On the other hand if you process is simple and stable a single screw can be much cheaper to buy. In a lab size single screws are often $ 25,000 +/- while lab twins are $ 100,000 +/-. Tom C
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zabielski
Senior Member Posts: 117
From:McHenry, IL USA
Registered: Nov 2002
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posted March 29, 2003 07:35 AM
Marilyn: When you do buy a pair of singles, be sure to highlight "FOOD APPLICATION" as I believe that both the barrel's and screws would have to be made from a stainless-steel alloy to gain FDA santions.I recall many moon's ago seeing one at a KRAFT Plant outside of Chicago. It was really impressive, and this is when I asked - why ar the barrels and screws made of SS? Such equipment has to be signed off by an FDA inspector (at that time, at least). So, the usual Lab Extruders your wanting to get may be a bit more costlier than a standard "lab" extrusion system. IP: Logged |
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