[Stoves] Modified Cinese Retail TLUD Camp Stove

[neiltm at uwclub.net]

On 30 Mar 2020 at 11:20, ajheggie at gmail.com wrote:

> I don't know why your post earned a spam flag Neil, I've edited it off.
> 
> 
> 
> On Sun, 29 Mar 2020 at 00:04, <neiltm at uwclub.net> wrote:
> >
> > Andrew's post taking me to the bioenergylists.org main page and seeing
> > Jim Tisso's modifications to the Chinese stainless steel ND camp stove I
> > use, prompts me to write with a different suggestion for modifying the
> > primary air to reduce soot and towering infernos with close to zero
> > moisture wood, especially after having conducted a recent experiment that
> > underlined for me how advantageous that would be.
> 
> I see the stove you refer to on stoves.bioenergylists.org but am
> unfamiliar with it, I presume it is sold online?
> 

Sorry, yes I assumed others would be familiar with it:

Just search for <woodgas camp stove> on ebay, and there are a few 
variations, mainly to the concentrator and pot stand which I suspect is 
probably interchangeable with the other stove bodies as my two are. I 
prefer the higher riser despite less pot stability from the closer 
support points.  And I guess there is less, as you say, flame quenching?

> Traditionally primary air controls power and you note also the moister
> the wood the more primary air. So I agree there must be good control
> of primary air over a range of feedstock, the exception would be
> something guaranteed to be homogeneous, like pellets.
> 

Yes, pellets are a whole different ball game, but not something I want to 
get into, especially when camping, as not having to carry or shop for 
fuel is one of the advantages and freedoms. If there really is no such 
thing as a dirty fuel then the challenge of burning variable biomass in 
this context seems yet to be met as optimally as I suspect it can be.

> > Secondly, soot is really not that much of a problem, given that it can
> > easily be wiped, brushed or washed off the pot, and the pot can be
> > carried in a plastic bag to contain the black.  It's not been a problem
> > for us a month away at a time.
> >
> This last bit worries me; to my mind the big reason for using top lit
> updraught is that it produces very few particulates, this is because
> the offgas is fairly rich and largely devoid of inert dilutants like
> CO2, N2 and H2O. If the pot has become sooty this points to the
> secondary flame having been quenched before completion. Possibly not a
> problem in a camping scenario but just what we want to avoid when
> considering indoor air pollution.
> 

Granted, yes.  That was the nice thing about the Reed FD TLUD woodgas 
camp stoves, that they left little stain usually on the pot, but they 
were also far more fuel fussy unfortunately, whereas the ND Chinese stove 
is more tolerant of a wider variety of fuel and moisture content.  

> It's at a time like this that we appreciate why indoor air pollution
> is significant in its effect on the respiratory system.
> 
> Take care and keep safe.
> 

Thanks.  I only ever use the stove outdoors, and endeavour as far as I 
can not to breath it, which can be easier said than done under some 
conditions when the wind seems to come from all points simultaneously!

Note how small this packs  - you could put it in an anorack pocket, yet 
it is a powerful stove that can be refuelled very tolerantly to extend 
the burn for substantial cooking, and can be kept burning indefinitely as
the ash can be agitated out through the grate with a stick.

The stove is most smoky with the driest fuel, reminiscent of a candle 
with too long a wick, so definitely not balanced under those conditions, 
but will burn much cleaner within a range of moistures in found wood, 
which is its primary purpose.  Great for stir fry in a wok though with 
the huge flame!  I don't find the stovetec rocket stove any less soot 
producing to be honest, but that's too big for our camping trips.

I think it ought to be possible to improve on by being able to vary the 
primary air, for a cleaner as well as a more variable fire, but ideally 
needs to be something manufactured to the same standard as the stove.  It 
would add cost obviously, but needn't be that much if kept as simple as 
possible.  Or it could be done as a bolt on - an accessory.

In the other direction there are occasions when found wood is too high in 
moisture, and my thoughts also extend to fan assistance under those 
conditions.  I find moisture content very hard to guess in the field, and 
often get caught out by a fire that won't sustain, but which fan 
assistance would overcome.  Probably a metal band collar that can be 
tightened around the external air holes with a single airway for a fan to 
blow through, that could be placed over the stove or removed while the 
stove was burning, as needed.

Fritz Handel designed the bushbuddy out of frustration with the Sierra 
stove, primarily because it would not work in ND mode without batteries, 
but was also not very stable.  The Solo is a mass produced copy of that, 
and the Chinese stove based on it, only with the advantage of being able 
to halve the height for more compact storage, and using a thicker guage 
of metal making it much cheaper in mass production than the hand crafted 
off grid spot welded titanium Bushbuddy, but without becoming 
prohibitively heavy for carrying.  Thomas Reed produced the two sizes of 
FD TLUD 'woodgas campstoves' before that, which became quite popular and 
which we enjoyed for many years, but like the Sierra, there was no 
possibility to use them in the event of running out of battery power, a 
bit heavy for carrying, and relative fuel fussiness as the trade off for 
a clean burn, not necessarily the highest priority of the camper.  
Ultimately, not this one anyway.

The Ukranian's have come up with  FA version, the 'Airwood Euro BM' which 
seems to be no more than a rather crude blow torch, and not really of 
interest.

I think there is room for a fourth stage to this niche, possibily along 
the lines I'm thinking, that retains the core versatility of the Chinese 
stove, as optional 'bolt ons' that add significant versatility without 
burdening with too much complexity.  I'd love to see this happen, as I 
think it would be a real boost to 'western' awareness and appreciation of 
the utility and whole concept of 'clean enough' burning of biomass.

Neil Taylor





> Andrew
> 
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