<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><DIV>Hi Crispin</DIV>
<DIV> </DIV>
<DIV>The fired bricks are physically strong and fire resistant when: the brick production recipe is followed, the clay is from a good source and they are well fired. The only problem we have with the firebox bricks is to train the masons to hacksaw the legs on the aluminum pots to be more like stubs, so the pots don't poke the bricks and crack them. </DIV>
<DIV> </DIV>
<DIV>For the outer shroud bricks they are unfired to save money and trees. If the clay quality is not that good we use lime as a binder to improve brick quality. <BR>We use moulds to shape the bricks and a double mould is used for the shroud bricks to speed production. There is not much heat on the outer bricks so we don't fire them. The one above the shroud door we use a combustion chamber brick to make it longer and more fire resistant. It's mostly the assembly that requires good training to get the lime cement subsoil mix well prepared and at the right mixture.</DIV>
<DIV> </DIV>
<DIV>The only bricks we ever cut were the original green undried purchased house bricks when we did our orignial prototyping to develop the dimensions of the bricks for both the combustion chamber and shroud bricks. Hand sawing bricks is tough!</DIV>
<DIV> </DIV>
<DIV>We are putting up kilns in communities and are trying to create a business model to develop other high value clay products with the kilns to help keep stove brick production costs low. Some of the communities with kilns are making water jars and others plan to make floor tiles to displace imports. It's a capacity building excercise with the communities but they are keen to innovate new products so I think some could be trained to build clay grates. Clay in west africa is an amazing renewable resource that could be used much more widely for the housing and cooking sector. </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>regards</DIV>
<DIV>roger</DIV>
<DIV> </DIV>
<DIV><BR>--- On <B>Thu, 1/24/13, Crispin Pemberton-Pigott <I><crispinpigott@gmail.com></I></B> wrote:<BR></DIV>
<BLOCKQUOTE style="BORDER-LEFT: rgb(16,16,255) 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><BR>From: Crispin Pemberton-Pigott <crispinpigott@gmail.com><BR>Subject: Re: [Stoves] Introducing a new low cost clay brick stove<BR>To: "'Discussion of biomass cooking stoves'" <stoves@lists.bioenergylists.org><BR>Received: Thursday, January 24, 2013, 3:25 PM<BR><BR>
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<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Dear Roger</SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"> </SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Those are very simple implementations of basic stove science. Well done.</SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"> </SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">How strong are the bricks? Can you saw them? Are the producers capable of making a round clay grate like the one shown in the Anglo SupraNova picture?</SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"> </SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">And how’s married life?</SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Crispin</SPAN></DIV>
<P class=yiv697434306MsoNormal><SPAN style="FONT-FAMILY: 'Calibri', 'sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"> </SPAN></DIV>
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<P class=yiv697434306MsoNormal>Hi Crispin</DIV></DIV>
<DIV>
<P class=yiv697434306MsoNormal> Yes I learned that trick from you and others, we have three other primary air holes on the first layer that enter behind the centre of the fire brick walls (so its not aligned) to help oppose air entry through the outer fuel hole. The fire box also is not enclosed tightly so air can get in between the bricks at the corners of the combustion chamber so it helps oppose the interior fuel hole air entry. With the round shroud, the pot can function as a plug to slow the airflow so we limit excess air to a reasonable level. All these factors help us get the air warmer before it enters the combustion chamber. </DIV></DIV>
<DIV>
<P class=yiv697434306MsoNormal> We have 4 secondary air holes, perhaps we could use more but the masons like to keep things simple. There are compromises on everything. We have found the more holes in the walls the more the structure is vulnerable and difficult to build. Our design aim is profound simplicity, easy to build and easy to use is whats working for us. Our biggest problem to date has been sorting out the mortaring and windows to stop the rows from breaking apart when they are banged with a heavily loaded pot. What we have now the local masons are pretty happy to work with and the women are very satisfied with the lack of smoke and fuelwood savings and speed. One thing that surprised me was how much people appreciated the safety of the stove for children.</DIV></DIV>
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<P class=yiv697434306MsoNormal> regards</DIV></DIV>
<DIV>
<P class=yiv697434306MsoNormal>roger </DIV></DIV>
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<P class=yiv697434306MsoNormal> <SPAN style="COLOR: #1f497d"></SPAN></DIV></DIV></TD></TR></TBODY></TABLE>
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