[Stoves] Anila Stove

[Ray Menke]

Thanks for responding.  Attached is a  112K composite photograph of
the experiment.  Earlier today, I fastened a fan (blower) from a
discarded microwave oven to the side of a coffee can, and put it under
the propane cylinder.  It made a good seal, so all the air had to go
through the fan, whether it was operating or not.  I did not remove
the material from the outer chamber of the cylinder, because a quick
inspection showed it was not completely charred.  Three cooking
projects were on the agenda;  Boil water for coffee and to fill a
large thermos bottle, make a pot of rice, and boil chicken scraps to
create chicken stock (broth).  I fired up the stove as before, and
each time I added fuel, I ran the blower so as not to create excess
smoke, and to create more glowing coals.  After three hours all the
cooking was done, with much less smoke, and some real firepower when
the blower was switched on!  Later, I opened the chamber and removed
the charred (torrified?) wood, and the bucket of paper scraps (lower
right photo)  Not all of the material was charred, so I think I need
to insulate the whole works.  At startup, I used the chimney as shown
in the upper left photo, but we later removed that and put the pot
holder several cm over the top of the cylinder coming out of the tank.
 (Upper right photo.)  The text indicates the propane cylinder is 12"
(30 cm) in diameter.  The lower left photo shows the bottom of the
tank and the 4 sided pyramid grate.  (Can't put a cone in a
rectangle.) This grate was shoved into the bottom of the square tube
with a tight fit, and then covered with a wire mesh that fits inside
the ring on the bottom of the tank, and then the blower can was
positioned, and the whole stove was set on top of this blower can.
The problem I am having is related to the varying amount of smoke
being released from the outer area. At the beginning, the stove burns
clean, but as the inner combustion area starts to heat up, and glows
red hot, it drives more and more smoke into the bottom of the burn
pot.  The fresh air supporting smoke free combustion just is not
there, so the fuel/air mix is not right, and smoke roars out the top,
especially if the stove is at the stage where it needs more wood.
Adding wood from the top cools the area even more, creating lots more
smoke!  Switching the blower on turns the thing into a FORGE, which
burns with no smoke, and throws a huge amount of heat into the pan
above.  This works fine with a big pot of liquid, but wouldn't work
for making flat breads (We make 32 Pita breads at a time, using black
cast iron skillets.  Each one needs to cook about 3 minutes, so that
currently means 96 minutes over Paul Anderson's Champion TLUD stove.)
The Anila type stove would seem to hold enough biomass to provide
extremely long cooking times, because of the reservoir of fuel.  I
just need to figure out a method of getting and keeping the proper
fuel/air mix.  (I've been telling people my little stoves were "smoke
burners"!)
I should once again point out that this is not an "Anila" stove as
designed by Professor Ravikumar, but an experiment inspired by his
creation.  These obsolete old style propane cylinders are made from
some good heavy duty material, and should last a long time, compared
to my tincanium projects.  The walls of the inner burn area
components(square tube and round tube welded together) are almost 1/4"
thick!

On Sun, Nov 14, 2010 at 12:53 AM, Crispin Pemberton-Pigott
<crispinpigott at gmail.com> wrote:
> Dear Ray
>
> Thanks for your description. Is it possible for  you to attach a modest JPG drawing of the stove (150k or so) showing the components and approximate dimensions?
>
> It sounds like too much primary air is being allowed to get to the fuel once a certain portion of the fuel has burned. In other words try it again with less primary air. It may be working in the beginning because the fuel is slowing the air flow.
>
> Once everything gets hot the thick walls may be conducting enough heat to roast the fuel with no air at all!  Hard to tell without a sketch.
>
> Good work and good luck experimenting.
> Crispin in Dakar



-- 
Ray  Menke
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