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

[Reedtb2@cs.com]

Dear Paul and All:

Sounds great!  I love the name.  I love the "minch".  I love the fact that 
you have only been working in stoves for 8 months, but have a potentially 
saleable stove COMBINING the best efforts of many on this list.  There's no 
substitute for DOING.  I hope you will have your 10 stoves ready for Spring.

You might consider "beta testing" the stoves by selling them (at cost?) to 
members on the STOVE list for them to test under their other conditions.  

I hope you will get a drawing program (I use Corel Draw) and draw a pretty 
picture of the concept complete with schematic raw fuel, pyrolysing fuel and 
charcoal and flames, even though I'm beginning to get the idea.

It would be nice to see a stove commercialized (US) or deployed (the world) 
from this list to pay for all the talk we've had.

Onward,                    TOM REED                    THE BEF STOVEWORKS





In a message dated 12/31/01 7:58:14 AM Pacific Standard Time, 
psanders@ilstu.edu writes:

<< 
 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.  &#8220;Juntos&#8221;  means 
&#8220;together&#8221; in Portuguese (with a soft &#8220;j&#8221; sound like 
the &#8220;ge&#8221; in protégé.  Or in Spanish with the &#8220;h&#8221; 
sound like in a political junta, making it sound like:  &#8220;hoontos&#8221; 
but not &#8220;hunt-tos&#8221;.   In either language, it still means 
&#8220;together&#8221; and is understandable by English speakers because of 
the &#8220;junta&#8221; term.
 
 Components of the Juntos stove:
 
 1.  Basket-shaped metal grate   ala New Dawn &#8211; Crispin PP
 2.  Rocket stove (small version)  ala Aprovecho &#8211; Dean Stills
 3.  True gasification unit   ala Reed-Larson
 4.  Can burn briquettes   ala   Legacy &#8211; 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 &#8220;top of the line model&#8221; 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 
&#8220;minch&#8221; unit, which is a 
 METRIC inch.). 
 One minch is exactly 2.50000 centimeters   (not the 2.5415&#8230;..cm in the 
English inch, which probably should be called an &#8220;einch&#8221;  )
 
 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 &#8220;gallon paint 
can&#8221; 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 &#8220;basket grate&#8221; (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 
&#8211; ( that is, fit inside) -  the lower can.  I like Crispin&#8217;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 &#8220;cooking spot&#8221; or the &#8220;cooking 
level&#8221;.  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 &#8220;burners&#8221; 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 &#8220;forced convection&#8221; options.
 
 8.  I could give more details on how I made one &#8220;basket grate&#8221; 
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 &#8220;chunky&#8221; 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 
measureing 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 &#8220;impressions&#8221; of what is 
&#8220;moderate&#8221;, 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 &#8220;Juntos&#8221;.   I can imagine seeing 
variations to be called   Juntos-2 and Juntos-3 and Juntos-3.C.7.    I 
consider the &#8220;Juntos&#8221; 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 &#8220;combination stoves.&#8221;  
 
 Likewise, I and we all must respect that the &#8220;Rocket Stove&#8221; is 
an Aprovecho name and product, so I should be referring to a 
&#8220;lower-side loading stove&#8221; 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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