<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="-webkit-text-size-adjust: auto;"><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="-webkit-text-size-adjust: auto;"><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="-webkit-text-size-adjust: auto;"><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="-webkit-text-size-adjust: auto;"><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div style="-webkit-text-size-adjust: auto;">Fellow stovers,</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">A few photos of a test natural draft TLUD set up:<br><br><img src="cid:29DBF043-2A1A-42DE-A52D-6C943BE34B3F" id="29DBF043-2A1A-42DE-A52D-6C943BE34B3F" width="640" height="480"></div><div style="-webkit-text-size-adjust: auto;">½ inch gap - for photography. Unit out of its outer safety can. This was set up inside my wood stove for a well vented, wind free, test run. As the flames rises above the center disk, the flame cools and turns yellow. Reducing the secondary air gap increases the temp in the system, increase ability to withstand drafty conditions, also increase the draft on the pyrolysis zone as well as on the air gap. Feedstock is standard wood pellets.</div><div style="-webkit-text-size-adjust: auto;"><br><img src="cid:7EB51256-603A-4188-9AB8-958B7F63D023" id="7EB51256-603A-4188-9AB8-958B7F63D023" width="640" height="675"></div><div style="-webkit-text-size-adjust: auto;">Center disk, a 2 inch washer in a 3 inch diameter can, is in place above the fuel but below the top lip of the reactor can. This also puts it below the secondary air gap as well. The gap between the reactor and the outer edge of the disk preserves about 55% of the draft capacity.</div><div style="-webkit-text-size-adjust: auto;"><br></div><div><span style="-webkit-text-size-adjust: auto;">According to Tom Miles, this disk, when use in larger furnaces, is called "</span><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">an aerodynamic flame holder ".</span><br><br><span style="-webkit-text-size-adjust: auto;"><img src="cid:B49FBDBD-8D1A-4789-A390-46B3BC7F217F" id="B49FBDBD-8D1A-4789-A390-46B3BC7F217F" width="640" height="589"></span></div><div style="-webkit-text-size-adjust: auto;">Supports for the draft can - one inch corner brackets. These are held in place by long bolts which will support the center disk as seen above.<br><br><img src="cid:B11B699F-3ECC-415A-A70A-84B294E22930" id="B11B699F-3ECC-415A-A70A-84B294E22930" width="640" height="853"></div><div style="-webkit-text-size-adjust: auto;">Three deflector washers set up inside the bottom of the draft can. The space between the center disk and the deflectors establishes a turbulent combustion zone.<br><br><img src="cid:DF77DB88-97EC-494C-9F9A-9A8AEDE298DE" id="DF77DB88-97EC-494C-9F9A-9A8AEDE298DE" width="640" height="640"></div><div style="-webkit-text-size-adjust: auto;">You cannot see the blue flames created when the hot pyrolytic gases rise above the edge of the center disk and meet the secondary air. The flames you see are orange as they have cooled as they rise above the center disk and the three defectors. At least this is what I think is the reason for them not being blue. As you can see, the deflectors prevent a central spire of flame - the inverted bathtub drain effect.</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">One effect of this approach is to keep the flames at a relatively constant distance from the target, perhaps a pot, as the the pyrolysis zone works its way down towards the bottom of the reactor and away from the target.</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">At the end of the run, the unit self extinguishes. When the charcoal is poured into a metal pot it has a hot, "sweet" smell. After it is quenched in water, it has a rather neutral nose. The charcoal crushes very easily and rinses off very easily as well. No floaters and no pellets not converted to charcoal: 100% conversion. Appears to be very nice stuff.</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">Next to try this on my three lbs coffee cans which have about a 6 inch diamter. To cover 45% of the fuel bed, I will try a center disk with a diameter of about 4 inches [⅔ the diameter of the reactor can.]</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">Notes:</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;"><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Alexis Belonio and Paul Olivier have been able to create clean burning stoves with blue flames in variable speed fan assisted TLUDs. What I am working on is maximizing the amount of blue flames in a natural draft TLUD.</span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);"><br></span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">This is purely an educational device to show the advantages of using a central disk over the reactor can to force the hot gases to the edges to meet the secondary air. This solves the problem of trying to get secondary air into the middle of the TLUD gas stream. A result should be to enable larger diameter TLUDs. Additionally, the central disk absolutely seals off about 44% of the diameter of the reactor. This substantially reduces the chances of oxygen getting into the top of the pyrolysis zone. Further, it retains heat within the system, creating a hybrid TLUD with some aspects of a retort.</span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);"><br></span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">This device also shows avoiding the central spire of flame.</span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);"><br></span></div><div><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);">Net net, I expect this approach will yield a cleaner exhaust gas steam and higher quality charcoal. Initial observations support this. If true, then this would be an improvement on older designs using concentrators with small diameter holes in the center.</span></div></div><div style="-webkit-text-size-adjust: auto;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);"><br></span></div><div style="-webkit-text-size-adjust: auto;">---------</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">Perhaps you will consider building one of these, trivial, and then testing it for emissions and quality of charcoal? If you are willing to consider this, I would be glad to send a few more details your way off list via email.</div><div style="-webkit-text-size-adjust: auto;"><span style="-webkit-text-size-adjust: auto; background-color: rgba(255, 255, 255, 0);"><br></span></div><div style="-webkit-text-size-adjust: auto;">Comments? Suggestions?</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">Many thanks for your consideration,</div><div style="-webkit-text-size-adjust: auto;"><br></div><div style="-webkit-text-size-adjust: auto;">Jock<br><br><div>Jock Gill</div><div>P.O. Box 3 </div><div>Peacham, VT 05862</div><div><br></div><div>Cell: (617) 449-8111</div><div><br></div><div><span style="font-weight: bold; text-decoration: underline; background-color: rgba(255, 255, 255, 0);"><a href="http://google.com/+JockGill">google.com/+JockGill</a></span></div><div><br></div><div><span style="background-color: rgba(255, 255, 255, 0);">:> Extract CO2 from the atmosphere! <:</span></div><div><br></div>Via iPad</div></div></div></div></div></div></div></body></html>