Has anybody got any definitive diagrams or proven theories when it comes to 
vanes in roaster drums?
50-60rpm 9 inch diameter solid.
Stuff like:
Vane height as a ratio to the diameter of the drum.
Number of vanes.
Shape of vanes eg tapering from one end to the other.
Angle of vanes to promote forward movement up a 10* slope. If the the angle 
is too severe with the beans be forced out the open front end of the drum? 
Apologies if that is a ludicrous outcome : )
Any and all information garnered through past experiences, or industry 
standards, much appreciated.
Stephen Frame

After trying an arrangement of two and four vanes running straight  
across, I then moved to a two vane configuration where one vane was  
angled to shift beans to the right and the other to shift beans to  
the left.  each vane covered about 1/4 of the diameter of the drum  
and about 2/3's of the length of the drum with the open end at the  
destination side.  Each vane was one inch tall in a six inch diameter  
drum.  The result was an agitation that not only rotated the beans  
toward and away from the drum surface but also moved the beans back  
and forth across the length of the drum.   I was quite happy with the  
results.
      Jim Gundlach
On Jan 4, 2006, at 9:33 AM, shark boy wrote:
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I have a 9" drum and use 1 1/4" high stirring vanes.  They work just fine.
*********************
Ed Needham
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] somewhere in the subject line of any email correspondence)
*********************

The vanes are there for agitation, to loft the bean through the air.  I would 
guess, from personal experience making a drum roaster from scratch, that 6 vanes 
at least 1" tall will work fine for loads up to one pound. Above a pound add 
more height to the vanes, say to 1.5"
<Snip>

My drum has six 1/2" vanes (made with SS "L" bracket).  Primary
purpose is to keep the bean mass from sliding across the drum.   The
beans closest to the vane are pulled toward the top, then fall down,
thus initiating a tumble.  The roasts are very even with this
arrangement.
I haven't noticed any problem with beans not roasting evenly, but the
angled vane idea makes sense to my pea-brain...  Possible mod?  Naw,
too much work......
Brett
On 1/4/06, Dan Bollinger  wrote:
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--
Regards,
Brett Mason
 HomeRoast
      __]_
   _(( )_  Please don't spill the coffee!

Four vanes works just fine.  I've built all shapes and sizes.  Four works.
*********************
Ed Needham
"to absurdity and beyond!"
ed at homeroaster dot com
(include [FRIEND] somewhere in the subject line of any email correspondence)
*********************