Re: Juntos (together) stove !!! This works!!

["Chris Smith" <hotspringfreak@hotmail.com>]

    Very appropriate stoves note Paul - however I found formatting tags included
in your messaging very distracting.  What format was your note sent in?  I would
like to read it as intended, before sent.  Checking the archive for an html
version didn't help much, so I converted to text format and removed tags
manually (which was laborious).  I hope you don't mind if I resubmit your
offering again here, making perhaps, easier reading.

    - Chris Smith
__________

 Juntos ("together") Stove report.

This is a new design and it works in initial trials.  After my December Africa
trip, I am back in frozen Illinois doing stove design work.  Ambient temperature
20 F ( -5 C), snow fluries, light wind, unprotected/unshielded stove and
aluminum pot, and I boiled a liter of water in 5 minutes.  I am happy (but also
glad to get indoors to write the report).  I have already named my new stove.
Juntos means together in Portuguese (with a soft sound like that in protégé.  Or
in Spanish with the sound like in a political junta, making it sound like
hoontos but not hunt-tos.  In either language, it still means together and is
understandable by English speakers because of the junta term.

 Components of the Juntos stove:

1.  Basket-shaped metal grate ala New Dawn Crispin PP

2.  Rocket stove (small version) ala Aprovecho Dean Stills

3.  True gasification unit ala Reed-Larson

4.  Can burn briquettes ala Legacy Richard Stanley

5.  Air-pipe ala Paul Anderson Includes pre-heated secondary air, TOP lighting
AND BOTTOM lighting sections, Fast initial heat, Long-term slow heat Smoke-less
when operational, almost smokeless at start-up.  Tincanium materials with
probable mud and brick options, Projected cost to be under $10 per unit, maybe
under $3 if not counting local labor and materials But we could also have the
top of the line model with $100 value (chrome plated and nice handles, etc??)
Burns most biomass fuels And this is NOT an April Fools joke.  It really does
work.  I have made and tested two of them.  Think of layers of tin cans, each
can has about a 6 minch diameter and a 7 minch height.  (Oh, by the way, I like
the metric system, so I have invented the unit, which is a METRIC inch.).  One
minch is exactly 2.50000 centimeters (not the 2.5415 cm in the English inch,
which probably should be called an einch).   So multiply the minch measurements
by 2.5 and you have the centimeter sizes.

4 minch = 10 cm
5 minch = 12.5 cm
6 minch = 15 cm
7 minch = 17.5 cm
8 minch = 20 cm
40 minch = 1 meter
...and 0.4 minch = 1 cm.

 Anyway, back to the stove

1.  The lower or bottom unit is a tin can (I prefer a gallon paint can because
it comes with a lip at the top edge) with about 6 minch diameter, open at the
top, and with plenty of air holes at bottom or around the lower outside edge.
It would be nice if this lower can could be about 10 minch tall (see #2 below)

2.  Insert a basket grate (ala Crispin) that is open at the top (diameter just
under 6 minch) and has a lip that seals reasonably well with the top of the
lower can (#1).  The bucket height needs to match (that is, fit inside) - the
lower can.  I like Crispin's basket grate that is about 9 minch high, so I
needed to have an elongated lower tin can for one of my initial stoves.  I made
a longer can by taping a second can underneath.

3.  The basket gate is sealed in its lower ¾ of length, and only the top quarter
has air holes in the side walls.  This means that air that enters the bottom of
the tincan is able to rise up the outside of the basket (thereby being warmed)
and then that air enters into the upper part of the basket as SECONDARY air to
be mixed with the gasification gases that are being generated below in the
basket.

4.  At the bottom of the basket grate is an airpipe the allows primary air to
enter at the bottom of the biomass fuel supply.  The air goes upward to the
gasification (pyrolysis) zone that is gradually burning downward after being TOP
LIGHTED.  All of this is ala Reed-Larson and their IDD unit, except that the
holes for the secondary air are in this lower unit, not provided by a gap
between the gasifier and the burner.  In other words, the gases are burned in
the upper part of the basket grate.

5.  Enter the Rocket Stove.  Basically I made an OPEN-BOTTOM small rocket stove
to place on top of the lower unit (#1-3).  I used a same-size tin can and placed
a wire grid at the bottom (top keep the chunky fuel from falling through the
bottom) and a side hole for inserting fuel pieces.  (My experiment had NO
insulation or second layer or shield around the rocket unit, so in my -5 degree
C environment, you can imagine how much efficiency I was loosing !!!!)

6.  ABOVE the top of the rocket stove I could place an additional ring (for more
chimney effect) or place a holder for the pot of water.  That holder is want I
will call the cooking spot or the cooking level I envision that in a real stove,
the cooking spot will be independently supported by bricks or metal or whatever,
and could look like the top of a stove with burners coming from underneath
and/or with a hot metal plate and a hot-water tank and whatever else the cook
wants.  In other words, the heat generation containers would NOT be required to
support the weight of the cooking pots.  And therefore the heat generation
containers can be inserted and removed from the area (a chamber?) that is below
the cooking spot.

7.  And an extra: I rigged up a bicycle tire pump to be able to force air into
the air pipe that provides the primary air to the gasifier.  I did not need it,
but it let me play with some forced convection options.

8.  I could give more details on how I made one basket grate that fit into a
gallon paint can.  I rolled some sheet metal, closed off the bottom, punched
some holes for the secondary air passages, added an air-pipe, and stuck it into
the paint can, sealing for air leaks as best as possible.

9.  Fire dynamics observed:

     a.  By itself, the lower unit (the gasifier) has the characteristics of the
NC (natural convection) IDD unit of Reed-Larson.  Not much draft.  Languishing
flames.  Nice but not sufficient to cook a real meal as currently configured by
itself.

    b.  The gasifier was loaded several times, mainly with the wood pellets
commercially available in the USA for pellet stoves.  I consider those pellets
(diameter 0.5 cm and variable lengths of 1 to 2 cm) to be too small.  I think
they block too much the flow of the air in the NC gasifier.  I am seeking some
more chunky fuel, maybe 1 x 1 cm to 2 x 2 cm sizes).  I did sometimes mix in
some sticks and some locust tree seed-pods and some birch-bark (wow!  for b-b)
just for seeing some impact.  I am NOT measuring fuel quantities.  I just want
to get an acceptable fire, then we can measure the heck out of it.

    c.  Into the Rocket unit, I placed various stuff.  Mainly twigs and broken
pieces of briquettes, and once a full Legacy briquette with center hole.
Everything burned VERY well.

     d.  Imagine the secondary flames for the gasifier unit licking at the
bottom of the fuel in the Rocket stove.  I hardly needed to think of lighting
the rocket area.  The fire quickly went to minimal smoke, with shooting flames
that would make any cook-in-a-hurry a happy person.  In fact, I was more
concerned about cutting back the fire!!  I noticed great action in the gasifier
unit.  The flames above must have been pulling in a draft of primary air.  I
only played a little with trying to limit the primary air via the air-pipe.

     e.  After the initial blaze with the rocket unit working great, those
rocket flames could be continued via the side-feeder hole, or allowed to
extinguish themselves.  Then the gasifier continued to put out nice moderate
heat that could keep a slow boil going.  (Remember that I was outside, below
freezing, and snowing slightly, and with no insulation on my stove, so do not
ask me for more than these impressions of what is moderate, etc.).

     f.  When flames were gone from the gasifier, I tried the air pump.  I had a
virtual forge in operation with glowing coals that eventually burned through
some of my makeshift metal materials!  To consume in the stove or remove the
charcoal is an open option.

10.  Discussion: It seems to work very well as a combination of our various
technologies.  Cheap at twice the price.  Subject to MANY variations and
refinements, including issues such as diameter of unit, and nature of the
basket-grate, and control of air in the air-pipe.  The stove really does bring
together stove components from several people.  And that is why I chose the name
Juntos.  I can imagine seeing variations to be called Juntos-2 and Juntos-3 and
Juntos-3.C.7.

I consider the Juntos name to be copyrighted for this style of stoves because
the stove has potential to make it into production.  If you want a generic name,
call them combination stoves.  Likewise, I and we all must respect that the
Rocket Stove is an Aprovecho name and product, so I should be referring to a
lower-side loading stove or whatever.  I invite everyone to participate with
this stove design work.  Crispin, I will probably be making an order for some
basket grates to my specifications, so you can start thinking of what the prices
could be and what materials you recommend.  I hope to have enough refinements by
February to seriously consider production of 10 or 100 for my March trip to
southern Africa.  Pictures?  Not needed.  Crispin and Dean and Richard and
Tom+Ron all have their websites to see the component parts.  All I had in the
back yard looked like 2 or 3 paint cans stacked on top of each other, with
flames at the top.

Sincerely, Paul

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