HomeRoast Digest

Topic: update on fluid bed testing an 8 qt galvanized funnel (5 msgs / 240 lines)
1) From: Michael Walls
Thanks for all the warning about using Galvanized
metal. I just tested with it using cold air. I bought
this funnel to test with because of it shape and its
low cost.  Here is a link so you will know what I
mean.  http://doityourself.com/store/6241533.htmIt is not a typical cone funnel. The sides are
vertical about 5 inches in height and the funnel
portion is not very steep. It allows for 2 lbs of
beans to spread out so that in the center the beans
are only 1 1/2 to 2 inches deep.
With a small 2 gallon 3.5 amp Sears Wet/Dry vac that I
used with a standard 600 watt dimmer.  I was able to
get a continuous foutain of beans flowing up the
center and back down to the sides. I had to use the
dimmer because full power would shoot them over the
top. I found that I got better flow without the
removable brass strainer screen,but with the screen
removed I had to get the air flowing a little bit
before adding the 2 lbs of beans. The beans would
settle in the 3 inch spout and stall the air flow. But
a simple solution was about 1/2 power, add the beans
and then increase to get the foutain flowing. I did
experiment with the center column design for about and
hour and found that I got better movement with it with
the  stainer screen in at the bottom. The flow is much
better without the screen or column. I will leave out
a screen and column from the next step. 
The next step is to make wide based funnel out
Stainless steel. My plan is drill a 3 inch hole in the
bottom of an 8 quart mixing bowl and add a sink drain.
Total Cost about $30 because of $15-20 metal hole
drill bit.  Can any one else think of a cheaper,better
way or where I can by one that is complete. 
 I spent way too much time playing in the garage on
Sunday afternoon and I ran out of Roasted beans last
night. The grill has finished preheating so it is time
to start roasting.  
Mike Walls,
Columbia, SC.
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2) From: peter zulkowski
Hi Michael,
Sounds like you are well on your way to making something that works.
As far as the hole goes, I have made holes like this by first drilling a 
pilot hole and then using my saber say with a metal cutting blade. Run 
the saw at the slowest speed and use lubricant. Should work fine.
I have been thinking of doing this same kind of an experiment, and here 
are some of my thoughts.
You blow hot air into the tube, and up the funnel, the beans get heated 
by the incoming air, but then they fall out of the stream into a cooler 
area. How do you insure that the whole mass stays at the temperature you 
want? Do you have to insulate around the outside of the funnel?
Michael Walls wrote:

3) From: Ed Needham
I'm going to build a small air roaster using a stainless canning jar funnel,
a piece of stainless screen and a heat gun.  The canning jar funnel has a
hole in it that is about 2 " in diameter and is a match made in heaven for a
heat gun to make an air roaster.http://www.happycookers.com/wc.dll/products/divulge/1-4837.htmlBed, Bath and Beyond also has them.
Sivetz has a setup similar to what I'm talking about as shown here,http://www.sivetzcoffee.com/online%20catalog.htm#30gmbut I think this would be even simpler and the shape of the canning funnel
might be even better.  Definitely easier to buy one than make it as he did,
and the stainless canning funnel is attractive in design too.  A chamber
mounted on the canning funnel would allow for a larger batch size and keep
the beans from going all over the place, as I'm guessing they might with
Sivetz design.
The idea of using a heat gun to roast coffee is definitely not my idea, but
using the canning jar funnel puts a new slant on it and might allow an easy
build for homeroasters who want to build their own.
Ed Needham
To Absurdity and Beyond!
homeroaster ... d.o.t ... com

4) From: GBL
Ed, thanks for the link to the ss canning jar funnel.
I've been scouring the restaurant supply stores etc., here in San Diego
for parts for experimental hot-air roasters for a couple of months now.
I've currently got a 10 ounce air-roaster working "proof-of-concept" with a
35,000 btu BBQ
Its a kluge but I will share the heat exchanger picturehttp://members.cox.net/kentaj/heatexchanger.jpg.Have you had any experience using hair driers as the hot air source?
I'm concerned about the air flow needed. Harbor-freight has 3 types of heat
for sale but they look like they might not have enough air flow to  float
even 1oz of beans.
I saw a 1600 watt  hair-drier in a thrift store the other day  and wondered
if it would have enough
air flow to fluidize 3 oz of beans for a sample roaster.
Of course not being designed for the high temp some mods might have to be
made...but for $5?
(posting after reading Ed's message in homeroast digest. #1617.  Not exactly
real time)
Original message:
on Tue, 2 Dec 2003 22:58:20 -0500
Ed Needham wrote:
| I'm going to build a small air roaster using a stainless canning jar
| a piece of stainless screen and a heat gun.  The canning jar funnel has a
| hole in it that is about 2 " in diameter and is a match made in heaven for
| heat gun to make an air roaster.

5) From: peter zulkowski
Wow GBL, I am impressed!
I picked up a Hair Salon Chair in a thrift shop very cheaply a few weeks 
ago, and found that it will 'float' a half  pound of beans very nicely. 
The problem was keeping them from blowing all over the garage!
The heat was another problem, and I was stymied with trying to heat such 
a large airflow to the right temperature, using electricity. May need to 
jump to 220 volts. In consideration of my electric bill, I have started 
thinking about supplying a gas heater for the unit. What you have will 
work just fine I bet.  Now if I can just find a heat exchanger in a 
thrift shop...
Thanks, for the JPG
GBL wrote:

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