<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0mm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{mso-style-priority:99;
mso-style-link:"Plain Text Char";
margin:0mm;
margin-bottom:.0001pt;
font-size:10.5pt;
font-family:Consolas;
color:black;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0mm;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0mm;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";
color:black;}
p.MsoNoSpacing, li.MsoNoSpacing, div.MsoNoSpacing
{mso-style-priority:1;
margin-top:5.0pt;
margin-right:0mm;
margin-bottom:5.0pt;
margin-left:0mm;
mso-add-space:auto;
font-size:11.0pt;
font-family:"Arial","sans-serif";
color:#1F497D;}
p.MsoNoSpacingCxSpFirst, li.MsoNoSpacingCxSpFirst, div.MsoNoSpacingCxSpFirst
{mso-style-priority:1;
mso-style-type:export-only;
margin-top:5.0pt;
margin-right:0mm;
margin-bottom:0mm;
margin-left:0mm;
margin-bottom:.0001pt;
mso-add-space:auto;
font-size:11.0pt;
font-family:"Arial","sans-serif";
color:#1F497D;}
p.MsoNoSpacingCxSpMiddle, li.MsoNoSpacingCxSpMiddle, div.MsoNoSpacingCxSpMiddle
{mso-style-priority:1;
mso-style-type:export-only;
margin:0mm;
margin-bottom:.0001pt;
mso-add-space:auto;
font-size:11.0pt;
font-family:"Arial","sans-serif";
color:#1F497D;}
p.MsoNoSpacingCxSpLast, li.MsoNoSpacingCxSpLast, div.MsoNoSpacingCxSpLast
{mso-style-priority:1;
mso-style-type:export-only;
margin-top:0mm;
margin-right:0mm;
margin-bottom:5.0pt;
margin-left:0mm;
mso-add-space:auto;
font-size:11.0pt;
font-family:"Arial","sans-serif";
color:#1F497D;}
span.PlainTextChar
{mso-style-name:"Plain Text Char";
mso-style-priority:99;
mso-style-link:"Plain Text";
font-family:Consolas;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
span.EmailStyle22
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.EmailStyle23
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:Consolas;
color:black;}
span.EmailStyle26
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Dear Darren<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>All those ideas are good.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Don’t make any changes now re the grate because as we discussed some months ago – you do not really know yet what will happen with wood so there is no point is stressing. You are the first to make this style and put wood only in it. We cut the wood very small (finger and thumb I call it) just for ignition. It has to pack pretty densely though. You will tell us what you think when you see it running.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Another option is out a re-bar grate on top of the grate which will have the same effect: limiting the amount of fuel that can fall/slide/shove under the ceramic bridge.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Note to Paul A: this approach (with a finer grate) will burn pellets, I am sure, with editing of the secondary air supply size and maybe position (though I don’t worry about that position – it’s pretty good).<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>+++++++++</span></p><p class=MsoNormal><br><span style='color:#1F497D'>…</span>I am weighing up whether to cut away some more material from the bricks at either side of the throat to give space to modify the grate angle and/or height once the stove is complete or if I should modify the grate (quite possibly make a new one from bar as you suggested) so that it would lift up between the bricks. I'm thinking it would be best not to cut the bricks. <br><br>I was just looking at pricing for refractory board to make the sloping sides in the upper part of the combustion chamber. I'm planning to have three boards on all sides except where the door is. <br><br>I'm looking at 300mm x 200mm x 10mm (soldering) boards - prices on ebay, about £10 each). My father rang me and I told him what I'm up to and he said he thought he had a sheet of fireproof roofing sheet (asbestos replacement), which his brother had given him, in his shed which should be big enough for what I need....<br><br>I've decided to add a second secondary air inlet on the front of the burner, if for no other reason than to have it inputting some hot air up by the window in the door to keep it clean. Also means I can play about adjusting primary air, flue damper, both secondary air inlets and see what effect each has on the burn in the combustion chamber.<br><br>I've got some fire cement I'm planning to use between the bricks to try to stop air leaking in through the gaps. Everything does fit together tight but I'm trying to seal the whole burner up so there are no air leaks where they are not wanted.<br><br>Best<br><br>Darren<br><br><br><br>On 25/11/2011 22:20, Crispin Pemberton-Pigott wrote: <o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Dear Darren</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>This is coming along well.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>></span><span lang=EN-US>Some photos are attached.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Got them, thanks.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br></span><span lang=EN-US style='color:#1F497D'>></span><span lang=EN-US>The door and hatch are made and have fire rope seals. </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Good move. The hopper should have no air passing through it. There is a pyrolysis zone above and near the primary air entrance, then a burning zone further to the left (back of the grate) then a gas burning zone above the rear of the grate ascending into the vertical chimney.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>></span><span lang=EN-US>I've used a cast iron grate from an old coal stove that was the perfect size.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>It looks really. I think you should expect to make two changes once you get going. One is to decrease the gap between the grate and the ceramic bridge (we found 75mm is perfect for the fuel we are burning) and to increase the 10 degree angle as a means for achieving this. That means lifting up the front or near end of the grate. What would make you want to try that would be excessive smoke caused by too much fuel burning at once. </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>We ran quite a number of tests with different spacings like 65, 70, 75 and 85 and 90mm but all having 10 degrees of slope. The 75 mm straight line distance was perfect. It gave an excess air ratio of 80-120% and extraordinarily low PM values for much of the time. Because your fuel is different you are going to have to do some hit and miss too until you get a really clean flame about 15 minutes after ignition and thereafter, no smoke. Hopefully it will perform as expected.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br>*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?<br><br><br></span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>This si going to be a very difficult question to answer without equipment. Suppose you have enough air but your 100mm grate gap is too big. It might incline you to provide more secondary air when you really needed to reduce the burn rate. At some point, you have enough power, so the air to match it is ‘X’ value. At a higher or lower burn rate, you need a different amount. You are gonna tell us what you need! I think the 20 x 20 may be too much but the fuel is different. The easy test is to open and close it when there is only a little smoke. It should make very little as it transitions from one firepower to another as it lights up. Somehow the feedback from you hand closing it will tell you which way to take things.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>If you can’t see any need for it, close it totally. It just add air with no effect other than to cool the output gases. If you need it, leave it open. We have not found any need to adjust the secondary volume when it is running. Most of the secondary air enters through the far end (back) of the grate where there is less fuel.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br>*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? </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>The expansion is important but not critical. If you can, do it. Professor Lodoysamba found that filling the combustion chamber with wood and top-lighting it provided immediate heat for cooking, very low emissions and easy ignition (automatic) of the fuel under the hopper. Very clever.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>When the fire reaches under the hopper, he had to shake the grate to move fuel down onto the grate. That is all in terms of attention.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>></span><span lang=EN-US>What effect does it have on combustion? what would happen if I leave them out?<br><br><br></span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>The effect of the bricks/ceramic is to improve the combustion by having hot walls. If you can’t get real refractory bricks second hand, use the hardest clay face bring you can find. It will last the longers in terms of off the shelf material.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br></span><span lang=EN-US style='color:#1F497D'>>…</span><span lang=EN-US>Hopefully I should finish and test fire it in the coming week.<br><br><br></span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Looking forward to more pictures and your comments.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>></span><span lang=EN-US>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) <br><br><br></span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>You construction matches the drawing.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br>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? <br><br><br></span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>The grate gaps look large which will create extra charcoal that might get snuffed in the ashes. Other than that it is fine. If the grate turns out to be too ‘coarse’ you can drop in a set of 12mm steel reinforcing bars welded into a grid. Works fine.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br></span><span lang=EN-US style='color:#1F497D'>></span><span lang=EN-US>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. <br><br><br></span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>You are going to have to try it with charcoal briquettes, wood pellets, wood, chopped up wood, coal and switchgrass cubes if you want us all to be happy! Good luck.</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Regards</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Crispin</span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span lang=EN-US> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><br><br><br><o:p></o:p></span></p><pre>_______________________________________________<o:p></o:p></pre><pre>Stoves mailing list<o:p></o:p></pre><pre><o:p> </o:p></pre><pre>to Send a Message to the list, use the email address<o:p></o:p></pre><pre><a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><o:p></o:p></pre><pre><o:p> </o:p></pre><pre>to UNSUBSCRIBE or Change your List Settings use the web page<o:p></o:p></pre><pre><a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><o:p></o:p></pre><pre><o:p> </o:p></pre><pre>for more Biomass Cooking Stoves, News and Information see our web site:<o:p></o:p></pre><pre><a href="http://www.bioenergylists.org/">http://www.bioenergylists.org/</a><o:p></o:p></pre><pre><o:p> </o:p></pre></div></body></html>