[Stoves] Heat / cook stove - proposed design

[Alex English]

Hello Darren and Crispin,

I have played with some of these gravity hopper or down feed burners, 
both large and small.  I would like to point out the obvious, that your 
"playing with fire" and risking explosion. Often its a minor 'POOF' but  
it is still enough to send smoke and sparks back through air intakes and 
into places you don't want them to go.  That is what can happen when you 
trap combustible gasses. If your using very dry wood you can generate 
potent gasses.

You have taken on a tricky task. I am trying something similar too. If I 
learn something useful I'll let you know.

Good Luck

Alex


On 09/01/2012 3:26 PM, Darren wrote:
> Hello Crispin,
>
> I was using some reclaimed construction timber, pine/conifer, 2"x2" 
> and cutting it to short lengths.
>
> I was only opening the lid on top of the fuel hopper to push the fuel 
> through under the bridge, to look at what was happening inside or to 
> add more fuel.  I appreciate that when I've got things set up properly 
> I only really want to open it to refuel.  I was slightly surprised to 
> find the hopper full of smoke - I guess I was expecting the air in the 
> hopper to remain static - happy to hear that this is normal.
>
> The wood on the hopper side of the grate was catching alight well.  
> The flames did appear to die back significantly when the wood/embers 
> that were on the combustion chamber side of the grate had burnt away.  
> I guess more testing will tell more.
>
> The original grate is not shakeable, the new one that is sitting on 
> top is.  I did this so I can vibrate ;) the fuel down the grate.  I've 
> now got 9cm from grate up to the bridge and this throat is about 10cm 
> wide.
>
> Hopefully I'll get a chance to fire it up with the new grate later in 
> the week.  I was thinking about experimenting with covering some of 
> the back of the grate. I'll cut some metal to fit and try this at some 
> point also.
>
> I guess ideally it would run without needing to shake the grate.  
> Unfortunately, the way the thing is constructed, lifting the bridge is 
> not an easy option.  I could more easily lower the grate which would 
> provide a bigger gap between grate and bridge and allow for wood to 
> fall through more easily, although I guess if this will also effect 
> the heat output?  Also I guess a steeper grate angle will help.
>
> Best
>
> Darren
>
>

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