[Stoves] Correcting a misconception that approaches myth status

[Paul Anderson]

Crispin,

You are entitled to your opinions.   Expressing them helps people see 
different points of view.   And there are so many variations that no 
lexicon would ever be complete.

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.com

On 12/16/2014 10:21 AM, Crispin Pemberton-Pigott wrote:
>
> Dear Paul
>
> I think this is an important modification of the fuel feed story that 
> is worth noting.
>
>     *>>*I fed in some wood vertically and it worked just fine. I
>     continued to do so and it continued to run long after it should
>     have gone out. Thus I proved to myself (and Paul) that TLUD's can
>     be refuelled but not too much at a time. OK, that was valuable and
>     contradicted received wisdom.
>
> >What Crispin did then in 2002 was what BP-Oorja, Biolite and Philips 
> and others did years later.   They were all trickle feeding additional 
> fuel into the TLUD well above the pyrolytic zone.
>
> This is not what I did. It is possible to make a gasifier that does 
> not have an MPF. Feeding such a device that has vertically stacked 
> fuel bed is quite possible. I realise this is not the same thing, but 
> we should not be diverted into thinking there is only one way to make 
> a gasifier. The fuel is tucked in alongside the other (charcoaling) 
> fuel and it works quite well. It was not anything like an attempt to 
> put fuel on top of a packed bed, if you get my drift.
>
> >And when the MPF reached the bottom, and with new fuel placed on top 
> of the char (not into the hot zone), the unit switched over to 
> operating with Bottom Burning (BB) as a rather normal UpDraft gasifier.
>
> Well, be careful here. It depends on how the fuel is patterned. If it 
> is not in a packed bed, it can gasify if the air is sufficiently under 
> control. Remember that gases can be produced with no air at all (in a 
> retort) so the switch from an MPF to a gasifier is not necessarily to 
> a bottom-lit updraft config.
>
> As I have written in "Micro-gasification Terminology: An Instructional 
> Summary of MG", available at my website.   See: 
> http://www.drtlud.com/wp-content/uploads/2013/11/micro-gasification-terminology-14nov2013.pdf 
>
>
>     Therefore, there are actually two types of TLUD (device name)
>     gasifiers, one being TLUD-MPF and the other being TLUD-BB.
>
>     Well, I don't agree that it is a TLUD if it is burning at the
>     bottom. It has ceased to be top lit if the combustion is taking
>     place at the bottom. I suspect the misdirection is caused by a
>     desire to force the combustion into a pre-defined set of modes.
>     The modes should instead describe the combustion.
>
>     The two types are quite distinctive in operation, and deserve
>     separate recognition and study. The common usage of the "TLUD"
>     name today means more than the TL of "Top-Lit" can signify. ......
>     snip ...  In essence, TLUD is a name for the small updraft
>     gasifier processes/stoves and is not a description of what process
>     (MPF or BB) is actually happening.
>
>     Just as I said. It certainly /is supposed to be/ a description of
>     what is happening. What would be the point of calling something a
>     crossdraft burner if it was not burning crossdraft? And vise versa.
>
>     However, we expect that in common usage, the TLUD name will
>     designate TLUD-MPF, unless the UD-BB mode is specified.
>
> >However, many people continue to ignore the transition from MPF to BB.
>
> This is still a limitation on the 'definitions according to Paul' 
> instead of describing what is taking place. There is an assumption in 
> the statement that we are burning chipped fuel. That limited view 
> cannot be allowed to overtake and limit all the possible 
> configurations. Paul, I think as someone very interested in 
> classification you should address this and come up with a more 
> complete lexicon.
>
> I repeat:
>
>     However, we expect that in common usage, the TLUD name will
>     designate TLUD-MPF, unless the UD-BB mode is specified.
>
>     Paul, that is currently your opinion and it is incomplete and
>     inadequate. We can't accept something that arbitrary.
>
>     First, there are at least 4 variations, not 2: TLUD with MPF, MPF
>     converting to BLUD, retort, and retort with at least some air. All
>     make combustible gas. What was happening on the porch was the last
>     of the 4.
>
>     Now what?
>
>     Crispin
>
>
>
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