[Stoves] small unit feeding continuously is not a small idea

[Legacy Mail]

Crispin, Alex, peter et al.,
re flow rate of pellets Crispin , I think it would also be a function of cross sectional area of the feed tube that would determine critical air velocities for potential back burn up the tube. I.e., for any given flow rate of pellets, the smaller the diameter the feed tube the faster they will be dropping thru it. 
Second point is that we speak of small stoves for this application: I look at the typical pellet stove and it is heating  a house and all you see is a small handfull of pellets being combusted ---AT ANY ONE TIME. 
Immediate ignition  ,near complete combustion, tremendous energy output. 

"Small unit / continuous feed" also challenges or at least tends to denude  the whole rationale and evolved declention on this list for  "top lit / bottom lit".  Viz., A pea-sized pellet  being continuously dribbled into a cup -sized combustion chamber and ignited almost spontaneously, is being lit from all sides at once   viz ; All lit.
Hmm...who will step up to the plate now as our new  Dr. ALUD...!

Seriously, developing a continuous feed      
mechanism that prevents bridging /jamming and back burn up into the feed stock is the thing to look at. Maintaining a critical air flow is one approach but it moves away from the simple easily replicated arena of "small village household" Capping the tube to prrvent any air flow up into it --while providing separate air inlet to the combustion chamber seems to make more sense for the kind of village small scale applications we are seeking.

Am all lit up about the idea frankly ,

Richard Stanley
www.legacyfound.org

Sent from my iPhone

On Oct 24, 2012, at 1:56, "Crispin Pemberton-Pigott" <crispinpigott at gmail.com> wrote:

> Dear Alex
>  
> I get ≈3 kW for that burn rate. Is that correct? Ideal for single pot cooking.
>  
> To develop your comment to Richard about the air flow, cover or not, I understand from Tom Reed that the superficial velocity is the marker for a fire occurring systematically in the hopper or not. If the air flow through the fuel is above some limit, the heat will not rise in the hopper. Yes?
>  
> Regards
> Crispin
>  
> >These pellets are feeding at a rate of about 0.7 liters per hour.  
> 
>  
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