[Stoves] Air power Re: Burning saw dust in TLUD stove

[Richard Stanley]

Crispin,
The sawdust at Dedza then hailed from the Wood Industries Corporation of Malawi. I first set eyes upon it in an attempt to find a higher capacity press but what I found instead was a collection of five complelely non functioning, parted-out   augur type sawdust-log making machines. They had come off a largish project started in the mid 80's there...
As to roaring inferno being generated as this kind of sawdust stove  gets going, I havent seen it perform much myself but it was in use then on a regular basis. I did nto see any misting feed mechanism though but then I asn ot looking too closely.The concept is as old as  the hills though. It  was mentioned way back  in the original Village Technology Handbook out of the VITA organisaion in the  late 60's ..

If that the case and you cannot dampen it , then the dribble/mist -feed idea seems a good option. something needed to regularly tickle any kind of such feed through a construction funnel or otherwise, is going to be needed though: Viz.,  a thin rough edged rod linked to a  flopping damper in the chimney ?

Frankly, I  would not recommend briquetting where I had  such a (sawdust) resource available and a fixed location for an applications outlet.. Its far too much work relative to what you could do with a little innovation in the stove feed vessle.

Think that bridging effects would  not only a function of number of partical diameters but also be effected by the grain shape. I think they called this the "roughness coefficient" back in Sedimentology 402.

On the concrete crushers just a quick and probably naive observation but why such an investment in thickness across the full diameter of the flywheel. Wouldnt it be far better to thin out the inside and fatten up the outside. The MV squared rule  has me thinking that you want the maximum percentage of available mass at the largest radius where it is moving the fastest...There is a far more elegant way to say that eh ?  

Did anyone think about making up a water tight ring chamber  with lots of baffles for filling with water as the mass ? Instead of using a solid metal disk. Think it might be far easier to transport and easier on the hands when you hit  really solid bits of rock concrete or steel rbar...etc.  It would, once drained of its water ballast, be lighter and allow far easier transport too. 
 Now don'tchya just love this kind of armchair defacto critique ? My apologies to the actual developers John et al. Please feel free to fire back and/or take it with a grain of salt if you want.

Kind regards, 
Richard...



On Jan 18, 2011, at 3:39 PM, Crispin Pemberton-Pigott wrote:

> Dear Richard
>  
> >On dedza pottery you must have gottn up there more recently. Greatly stop enroute to from Lilongwe, eh ? 
>  
> It is an interesting place and the gift shop is amazing. I stayed there only once at the B&B.
>  
> The makes proper refractory linings for kilns which, interestingly enough, are not really up to the beating that stoves offer (because they are not made for rapid temperature cycling).
>  
> There is literally a mountain of sawdust across the road from a mill.
>  
> >On stone crushing I have to wonder why a new form of post quake architecture has not evolved yet
>  
> There is certainly a lot of talk about it. J Currelley says a lot of the damage and deaths were caused by poor quality concrete, in part from a weak host rock and in part from lousy concrete making skills. The Georgia Tech guys found that they can double the strength of the concrete by mixing am making it properly which is a Good Start.
>  
> >...Homes built up entirely out of rubble removed ex crushing or with a minimum of same. Probably has eh ? 
>  
> It seems the preference is to make new blocks and pours. There isn’t much you can do with a large cracked and folded slab of steel reinforced concrete except reduce it to <19mm aggregate.
>  
> John broke a few things getting the machines set up (sheared off pins) and now it seems they are ready to rock. As every home needs a roof and a stove, the connection seems obvious: make as much of the stove as possible from crushed rubble. Perhaps substantial outdoor cooking stoves with inserts.
>  
> They like large pots and there are so many existing large charcoal stoves, they can be set into air-controlling structures that cost only little to make on site. Jobs…recycling…fuel efficiency, maybe a fume hood – the whole kit and caboodle.
>  
> Time to be imaginative.
>  
> Regards
> Crispin
>  
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