[Stoves] Central channel combustion stoves. Was RE: Henson Center Fiure Burner System

[Paul S. Anderson]

Stovers,

I agree that Lanny has put something fresh into the options about 
stoves.  I say
"fresh" (as in a new perspective on something that exits) instead of "totally
new" because central channels (centralized vertically in the fuel) is found in
the packed-sawdust burners and in the holey briquettes of Richard Stanley, and
probably elsewhere.

The defining characteristic is the central channel, and that is a generic
descriptor of a fuel configuration for combustion.  (Feel free to 
propose other
names for the GENERIC descriptor of all such combustion devices with a central
channel.)  The specifics of the "Henson Center Fire Burner System" deserve
recognition of the inventor, and I applaude Lanny for having led us all to
examine central channel combustion.  I hope that he will lead us all and will
eventually produce a named stove that reaches the markets and the people.

What is fresh (innovative, new perspective) in what Lanny has accomplished is
that the fuel is NOT packed tightly as in the two previous examples.  Instead,
a central channel is created by a structure (wire basket or highly-perforated
cylinder) that prevents the fuel from collapsing into the central 
channel. This has several highly significant impacts on stove 
technology.

1.  The fuel is relatively loose (not packed like the sawdust or briquette
fuel).

2.  Therefore, the liberated gases can move more easily through it, with
preference (least resistance) toward the central channel where the heat of
combustion can ignite these arriving gases, continuing to drive the upward
movement of the air/gases, creating a lower pressure in the center, 
that favors
drawing in more of the gases.

3.  The fuel can be of many, many types of dry biomass provided that the
openings in the basket/cylinder are sufficiently small to prevent much (some
could be allowed?) falling through of the raw fuel.  And still large 
enough for
ash (not char) to fall through, perhaps if occassionally shaken or 
probed.  Many
types?  How about everything from rice husks and loose sawdust to lumps of
charcoal and perhaps even vertically placed long wood sticks.  Corn cobs would
be very good, as would wood chips and pellets and small-diameter briquettes
(not the briquettes that are large and with a hole).

4.  This device could be made to be continuous feed for continuous 
operation. (My example here is with the pot removed for refueling, but 
other ways could
possibly let the pot remain in place.)  The new fuel should probably be
inserted downward and to the outside of the fuel container, thereby 
forcing the
earlier fuel toward the bottom and toward the center.  This could also 
assist in
ash removal either through the central channel (be careful of up-draft 
carrying
the ash up to the pot, so refuel when the primary air has been cut off for a
couple of minutes), or downward through openings in the bottom of the "donut"
of the fuel holder.

5.  Even without refueling, the central channel keeps pulling the gases 
into it,
leaving the outside walls of the fuel container relatively cool (adding much
life to the metal of those walls).  When the fuel does burn outwards, it is
highly likely that the loose fuels will fall downward (especially if 
stimulated
by shaking or probing), filling in the voids, and returning more to the 
burning
(use of the oxygen in the available air) that is closest to the air 
flow in the
central channel.

6.  A major research question is the optimal diameter (or shape if conical or
otherwise) of the central channel, with variables of fuel types and desired
heat output.

7.  Another question is the impact of placing "things" down into the central
channel.  Things could be flame spreaders or turbulance stimulators or flame
retainers (wrong name, but you know what I mean), or even entrances for
secondary air.

8.  The central channel combustion is combustion where the making of the gases
from the solid fuel is mixed in with the combustion of those gases.  
Therefore,
it is NOT a gasifier in which the creation of the gases is able to be 
identified
as separate in time and space from the combustion of the gases.

9.  Could someone please explain and provide a contact for the statement made
days earlier that
>> Yes a number of examples have been posted now to which I will add the
>> combustible tube tlud stove that someone here built. [snip]

Although I am highly involved with the T-LUD technology, I have no 
knowledge of
that is mentioned above.

*************

Personally, I will certainly be eventually making and examining the central
channel combustion with loose placement of fuels, and I will always credit
Lanny Henson with initial experiments and reporting that has brought this
technology to our attention.

Paul


-- 
Paul S. Anderson, Ph.D., Geography professor - Emeritus
Telephone:  USA-309-452-7072 (residence and office)
Internet site:  www.ilstu.edu/~psanders
For my gasifier stoves info, go to (below) and click on my name:
http://www.repp.org/discussiongroups/resources/stoves/contributions.html

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