Darren Just send me the photo and I'll post it.
Tom Miles Stovess List Owner T R Miles Technical Consultants Inc. [email protected] Sent from mobile. On Nov 25, 2011, at 5:26 AM, Darren <[email protected]> wrote: > Resent a third time with the photograph attachments stripped (suspecting that > the combined size of attachments may be stopping it getting through - > apologies if you get this three times!!) > > -------- Original Message -------- > Subject: Fwd: Re: [Stoves] Heat / cook stove - proposed design > Date: Fri, 25 Nov 2011 13:18:38 +0000 > From: Darren <[email protected]> > To: [email protected] > > Resent as it didn't appear to get to the list (apologies if this comes > through twice) > > -------- Original Message -------- > Subject: Re: [Stoves] Heat / cook stove - proposed design > Date: Fri, 25 Nov 2011 02:52:47 +0000 > From: Darren <[email protected]> > To: Discussion of biomass cooking stoves <[email protected]> > > Getting close to completing this stove now. > > Some photos are attached. > > I've also attached a drawing of how things stand now (not to scale) > > The door and hatch are made and have fire rope seals. These will be fitted > once everything else is together. > > I've used a cast iron grate from an old coal stove that was the perfect size. > > A couple of things I'm wondering > > *At the moment all the secondary air is going in through some square section > pipe with an internal diameter of 20x20mm that enters at the rear of the > combustion chamber above the ceramic blocks. (shown as blue square in > stove2-7.jpg). Is this going to supply enough air or should I put a similar > sized secondary air inlet on the front of the stove also? > > *Crispins GIZ design has an area where the combustion chamber tapers > wider (an expansion chamber?). I've drawn this in green in stove2-7.jpg . > How important is this? I could make these sloping walls from sheet steel or > I guess buy some refractory material sheets (my x partner who is making this > with me had some jewellers heat mats that would appear suitable although she > appeared reluctant to give them up) Is this a crucial detail? What effect > does it have on combustion? what would happen if I leave them out? > > Thanks in advance for any pointers. Hopefully I should finish and test fire > it in the coming week. > > Best > > Darren > > > > > > On 06/11/2011 22:33, Darren Hill wrote: >> >> Hello Everyone, >> >> After this project going well onto the back burner as it warmed up here, the >> temperature we are seeing at night now is focusing my attention again. >> >> If anyone is interested discussion about this started 29th December and went >> on until 23rd February. The stove is about half built- I'm going to be >> working on it again on Tuesday. >> >> I've attached a diagram of how I'm now planning to build the grate and >> throat area. (I took the liberty of modifying the GIZ diagram Crispin >> kindly sent to explain an appropriate layout) >> >> As I'm only going to be burning wood and in my experience of wood stoves all >> the wood burns to a light ash which would easily fall through the grate I am >> planning to have a stationary grate. Am I making the wrong decision here? >> >> I'd welcome anybodies thoughts on things as they stand. >> >> Hoping to get it finished soon. Considering the number of people I've been >> describing it to all year it would be good to also let them know how it >> works!!! I've never seen anything like this in action - I'm thoroughly >> intrigued. >> >> Best regards >> >> Darren >> >> ------------------------------------------------ >> >> >> [Stoves] Building my Heat / cook stove. >> Crispin Pemberton-Pigott crispinpigott at gmail.com >> Wed Feb 23 21:46:01 PST 2011 >> >> >> Dear Darren >> >> >> >> I think you are going to have a couple of problems with the layout as drawn >> and they are solvable. >> >> >> >> Let's look at them all: >> >> >> >> 1. The restricted height at the entrance of the combustion area is >> probably the right height, but that is for limiting the amount of fuel that >> can fall onto the grate further in. >> >> 2. The grate needs to extend into the whole area under the combustion >> zone or else it will fill up with ash and you don't have a way to get it >> out. The grate is correctly placed, perhaps a little steep but that can be >> altered. Char and ash will fall forward (as it should) but end up in the >> bottom of the combustion area. >> >> 3. The constriction you describe well on the side is going to catch >> some of the char and ash and might (or not) create a bridging problem. You >> can address that if it happens. >> >> 4. The purpose of getting the grate under all the horizontal area >> solves two things: it allows a lot of controllable air to reach the far end >> of the grate where there will always be less fuel. That means air gets >> through and effectively becomes secondary air. If you make the grate >> shakeable, you can clear the ash but you will need to have it stop at a >> vertical or inclined surface or the bottom will get blocked. >> >> 5. We are having pretty much the same layout but the restriction is >> above the grate about 100mm. This allows the grate to carry enough fuel and >> still have all the gases and smoke and flames come together above the fuel. >> >> 6. We start the fire by placing some fuel on the grate, extending into >> the part below the combustion area then top-light in the combustion area. >> The fire works its way back to the fuel hopper it the top is left open. Then >> when it is well established, close the hopper and vary the air with the >> controller you indicated. >> >> 7. The key change is the extension of the grate, perhaps at a lower >> angle. We are using 15-20 degrees but there is nothing magic in that. >> >> 8. I have attached a drawing of the GIZ 7.1 combustion chamber that >> worked very well using all the principles mentioned. Note the angled piece >> on the right. This protects the grate from becoming blocked from movement by >> trapping something between it and the wall, when shaken. >> >> 9. Note the constriction above the left side of the grate. It is 100 x >> 80mm. As you look at the side view drawing, the grate is 155 deep. That >> means the moving part is about 260 x 155. >> >> >> >> Regards >> >> Crispin >> >> >> >> >> >> >> >> From: stoves-bounces at lists.bioenergylists.org >> [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Darren Hill >> Sent: 21 February 2011 20:40 >> To: Discussion of biomass cooking stoves >> Subject: Re: [Stoves] Building my Heat / cook stove. >> >> >> >> Hello Crispin, >> >> The bleed is at top bypassing the need for gases to go down past the heat >> exchanger. >> >> Secondary air is flowing in through some 20mm x 20mm internal diameter >> square section tubing. Is this enough or do I need more? Another 20mm x >> 20mm square section tube? More? >> >> I've attached another diagram which shows things as they are currently >> planned/progressing. >> >> Looking at this diagram. Are you saying to have some of the grate to the >> left of the red line I've drawn on the diagram? >> >> Currently this is the thinnest point (or bottle neck, or throat) and has a >> vertical ceramic slab either side so that this 'throat' is not the full >> width of the hopper. Extending the grate further to the left will, in >> effect, increase the area of the thinnest point. I currently plan to have >> the lowest part of the grate level with the bottom of the ceramic block >> (that is the floor of the combustion chamber) so it is away from the >> thinnest/hottest area. >> >> Is it best to shift the grate to the left? >> If so what % of the grate left of the red line? >> Should I also raise the grate so that the its level with the top of the >> ceramic block that is the floor of the combustion chamber? >> >> I'm working on the stove today and tomorrow. Going to build the air tight >> doors today. >> >> Best >> >> Darren >> >> >> >> _______________________________________________ >> Stoves mailing list >> >> to Send a Message to the list, use the email address >> [email protected] >> >> to UNSUBSCRIBE or Change your List Settings use the web page >> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >> >> for more Biomass Cooking Stoves, News and Information see our web site: >> http://www.bioenergylists.org/ >> > <stove2-7.jpg> > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web site: > http://www.bioenergylists.org/ >
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