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Topic: playing with a WBI (9 msgs / 155 lines)
1) From: Ken Mary
I spent some time trying my suggestions from a previous post to increase the
airflow through a WBI. Shimming the fan motor to bring the fan blade closer
to the housing did nothing, the blade is already close enough. The internal
recirculation is not significant. Removing the fan blade end plate reduced
the flow as I assumed. But it is nice to prove it.
Removing both bottom covers as others have done, did significantly increase
airflow, as observed by bean movement and outlet static pressure
measurement. I plan to reinstall the plastic cover with a hole, maybe 2 or 3
inches diameter, screened-over to keep chaff out. The metal cover is in the
trash.
Drilling some holes in the roast chamber bottom plate will do nothing since
it is sealed off from airflow by the ceramic disk.
--
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2) From: AlChemist John
Sometime around 11:01 2/7/2003, Ken Mary typed:
<Snip>
I found this also
<Snip>
Same here again with both covers remove, but simply have the covers off 
with no chaff problems.
<Snip>
Sort of true.  If you also put holes along the outer edge of the bottom 
plate and in the center, then it is no longer cut off as the plate is not 
flush with the ceramic disk.  Air can flow down through the  outer holes, 
between the plate and disk and up through center holes.  Don't bother 
though with a regular WB though.  Air flow does not increase, vortexing 
fluid action is reduced with the slight division of air and capacity 
remains the same ( or slightly lower)
If one were to completely block the side vortex vents and only blow from 
the bottom, who knows?  Likewise, I have not tried the above mod on my 25v 
boosted motor WBI.  Could be that on an unmodified fan, the air restriction 
is input air, but on a boosted fan the limitation could be output 
holes.  Probably worth trying with some spare time.
<Snip>
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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3) From: Ben Treichel
I wouldn't do anything to lessen the "vortexing fluid action" since this 
is what allows for a bigger roast. I've convinced myself that if my 3 oz 
FR did that instead of trying to lift the beans that it would have been 
a 4 oz roaster.
<Snip>
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4) From: AlChemist John
Sometime around 07:03 2/8/2003, Ben Treichel typed:
<Snip>
Actually, I don't agree with this.  I thought this might be the case but 
after converting my FR (temporarily) to a vortex, nothing changed capacity 
wise.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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5) From: Ken Mary
<Snip>
In my WB1, there is a cold spot in the center of the bottom plate, measured
by IR. Next time I will look at drilling the plate to force some hot air
through it. I see that if the plate is drilled near the edge upstream of the
side vents, there may be enough pressure to force the hot air under it to
holes near center.
I have done this in a newer popper to provide some upward lift to the beans
in addition to the spinning motion.
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6) From: Ben Treichel
AlChemist John wrote:
<Snip>
How did you do it? Did you eliminate the chamber so that the beans were 
next to the vents?
<Snip>
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7) From: AlChemist John
Sometime around 10:45 2/8/2003, Ben Treichel typed:
<Snip>
Yes, basically.  Made a chamber out of a small cylinder with canted vortex 
openings.  Set the whole thing down in.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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8) From: Ben Treichel
Ok, but it seems that the simplest solution is to put a dimmer on the 
fan (with the bridge still in place) and control it that way. I'm doing 
4 oz roasts in mine that way. However, I also used a tin can to extend 
the chamber by about an inch. I start out at 17 or 18 volts, and drop 
from there as the beans dry out. It also seems that I start at a higher 
initial voltage (100 vs 95), but end up at the same ending voltage, 
around 102.5 or 105. However I do dial the fan voltage down some (2 or 3 
volts).
Also as I was wiring in the 2nd variac (rebuilt after failure) I was 
struck by the thought that it might be possible to achieve 85% of what I 
have by varying fan voltage only. A lot cheaper also since the fan takes 
less than 1/10th the power, so a dimmer is a lot cheaper part.
Ben
AlChemist John wrote:
<Snip>
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9) From: AlChemist John
Sometime around 20:21 2/8/2003, Ben Treichel typed:
<Snip>
Seems we have veered to a FR discussion I think.
Making the FR vortex was not a solution, just a  failed test.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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