<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><br>Interesting, is this self regulating?</div><div><br>On May 15, 2014, at 9:39 PM, Crispin Pemberton-Pigott <<a href="mailto:crispinpigott@outlook.com">crispinpigott@outlook.com</a>> wrote:<br></div><blockquote type="cite"><div class="WordSection1"><div><div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0mm 0mm 0mm"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">I can suggest one additional effect to try which is to put a shell around the outside that is closed to the body at the bottom and open at the top. This is a down-drafting secondary air preheater. The height of the upper lip strongly affects the performance so you need to find where to put it. The effect of this is to create a negative draft on the secondary air supply that balances the heat inside in such a way that you get the exact airflow level you want at different power levels.</span></p></div></div></div></blockquote><blockquote type="cite"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Crispin</span></p></div></blockquote><style><!--
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