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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>Dear Paul<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'>I think this is an important modification of the fuel feed story that is worth noting.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>>></span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>I fed in some wood vertically and it worked just fine. I continued to do so and it continued to run long after it should have gone out. Thus I proved to myself (and Paul) that TLUD’s can be refuelled but not too much at a time. OK, that was valuable and contradicted received wisdom. </span><o:p></o:p></p></blockquote><p class=MsoNormal><span style='color:#1F497D'>></span>What Crispin did then in 2002 was what BP-Oorja, Biolite and Philips and others did years later. They were all trickle feeding additional fuel into the TLUD well above the pyrolytic zone. <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>This is not what I did. It is possible to make a gasifier that does not have an MPF. Feeding such a device that has vertically stacked fuel bed is quite possible. I realise this is not the same thing, but we should not be diverted into thinking there is only one way to make a gasifier. The fuel is tucked in alongside the other (charcoaling) fuel and it works quite well. It was not anything like an attempt to put fuel on top of a packed bed, if you get my drift.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>></span>And when the MPF reached the bottom, and with new fuel placed on top of the char (not into the hot zone), the unit switched over to operating with Bottom Burning (BB) as a rather normal UpDraft gasifier. <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Well, be careful here. It depends on how the fuel is patterned. If it is not in a packed bed, it can gasify if the air is sufficiently under control. Remember that gases can be produced with no air at all (in a retort) so the switch from an MPF to a gasifier is not necessarily to a bottom-lit updraft config.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal>As I have written in "Micro-gasification Terminology: An Instructional Summary of MG", available at my website. See: <a href="http://www.drtlud.com/wp-content/uploads/2013/11/micro-gasification-terminology-14nov2013.pdf">http://www.drtlud.com/wp-content/uploads/2013/11/micro-gasification-terminology-14nov2013.pdf</a> <br><br><o:p></o:p></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal>Therefore, there are actually two types of TLUD (device name) gasifiers, one being TLUD-MPF and the other being TLUD-BB. <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0mm;margin-right:36.0pt;margin-bottom:5.0pt;margin-left:0mm'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0mm;margin-right:36.0pt;margin-bottom:5.0pt;margin-left:0mm'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Well, I don’t agree that it is a TLUD if it is burning at the bottom. It has ceased to be top lit if the combustion is taking place at the bottom. I suspect the misdirection is caused by a desire to force the combustion into a pre-defined set of modes. The modes should instead describe the combustion.<o:p></o:p></span></p><p class=MsoNormal>The two types are quite distinctive in operation, and deserve separate recognition and study. The common usage of the “TLUD” name today means more than the TL of “Top-Lit” can signify. ...... snip ... In essence, TLUD is a name for the small updraft gasifier processes/stoves and is not a description of what process (MPF or BB) is actually happening. <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0mm;margin-right:36.0pt;margin-bottom:5.0pt;margin-left:0mm'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0mm;margin-right:36.0pt;margin-bottom:5.0pt;margin-left:0mm'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Just as I said. It certainly <i>is supposed to be</i> a description of what is happening. What would be the point of calling something a crossdraft burner if it was not burning crossdraft? And vise versa.<o:p></o:p></span></p><p class=MsoNormal>However, we expect that in common usage, the TLUD name will designate TLUD-MPF, unless the UD-BB mode is specified.<o:p></o:p></p></blockquote><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>></span>However, many people continue to ignore the transition from MPF to BB. <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>This is still a limitation on the ‘definitions according to Paul’ instead of describing what is taking place. There is an assumption in the statement that we are burning chipped fuel. That limited view cannot be allowed to overtake and limit all the possible configurations. Paul, I think as someone very interested in classification you should address this and come up with a more complete lexicon.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal>I repeat: <o:p></o:p></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal>However, we expect that in common usage, the TLUD name will designate TLUD-MPF, unless the UD-BB mode is specified.<o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Paul, that is currently your opinion and it is incomplete and inadequate. We can’t accept something that arbitrary. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>First, there are at least 4 variations, not 2: TLUD with MPF, MPF converting to BLUD, retort, and retort with at least some air. All make combustible gas. What was happening on the porch was the last of the 4.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Now what?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p></blockquote></div></body></html>