<div dir="ltr"><div style="font-size:12.8px">Hi Kirk,</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Maybe i have named the top of the combustion chamber with the wrong word (concentrator ring). The combustion chamber has on top a 3 inch hole, and no secondary holes inside the combustion chamber below the concentrator ring.</div><div style="font-size:12.8px">The 3 inch hole "concentrate" the smoke to the tube burner.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">When the primary air control is wide open, i can obtain a good flame with a taller internal chimney to increase draft. Another way to increase secondary air flow without a chimney is to add a fan.</div><div style="font-size:12.8px">The experiment, with a taller chimney, also make me doubt about the importance of the venturi effect versus the draft of a chimney. With a normal TLUD burner (Peko Pe or Champion stove for example) you can also have a short flame with a taller chimney.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Another way, as you say, is to add more than one burner.</div><div style="font-size:12.8px">I have made sometime ago, an experiment with 4 similar burners on top of a 18 liter chamber. The problem i had, is that always a burner draft "lose" vs a stronger draft of another burner. The weakest burner acts like a primary air control, and i never had a "positive" draft for all of the burners at the same time. If i restrict the weakest burner, another burner take the place with negative draft.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">The solution is to put a fan at the primary air control, like Paul Olivier did, or with the subdivision of the combustion chamber in 4 independent chambers, each with his own burner on top. All of the 4 independent chambers can "share" the same primary air control below.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">I have no equipment to test particulates or gases. The equipment are very expensive for me. I am not a stove constructor (yet). But i thing the stove would have very good results. Maybe you, Julian or Crispin can contruct this burner and make some measurments to test it.</div><div style="font-size:12.8px">I have made some variations of the tube, with distinct sizes and holes configurations, and i found this is the best configuration for now (best looking flame).</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Thanks for the photos of the control valve. Maybe i will construct something similar.</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Here are some photos of the same burner (tube and cone) and the same beer barrel, in another similar configuration stove:</div><div style="font-size:12.8px"><br></div><div style=""><span style="font-size:12.8px"><a href="https://www.dropbox.com/sh/af6b6gfihhw4psj/AAD6cuP8q4PMGTCDSMJqfXDGa?dl=0">https://www.dropbox.com/sh/af6b6gfihhw4psj/AAD6cuP8q4PMGTCDSMJqfXDGa?dl=0</a></span><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">This is a video of this stove with a taller chimney:</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><a href="https://youtu.be/j6BfGrPsvt8" target="_blank">https://youtu.be/j6BfGrPsvt8</a><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Greetings</div><div style="font-size:12.8px">Roberto Poehlmann</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">"</div><div style="font-size:12.8px"><span style="color:rgb(0,0,0);white-space:pre-wrap">Roberto,</span></div><div style="font-size:12.8px"><pre style="white-space:pre-wrap;color:rgb(0,0,0)">Nice. I would like to see test results for particulates. It should be very clean. It looks like it is loosely based on Crispins flame tube design with holes added in the tube where the Venturi low pressure area is. The holes are at the bottom of the burner, so there is better draft and a good burning area above. If I understand correctly Crispin is using the tube differently, to concentrate the heat and increase the dwell time for the flame in that hot environment. His secondary air is all added before the flame tube. Your design looks more compact and perhaps would be a better choice for a TLUD.
There is a limit to how much gas the burner can handle. When the foil is removed and more primary air is added the burner is overloaded with gas and a tall diffusion flame forms. I have been trying to handle this problem by adding more mixing capability, and have had some improvment, but further work is needed. The problem with the mixing tubes I am using is that along the edges of the combustor, the air exiting the tubes exits at an angle instead of straight out. This holds the gasses below the burner along the edges, and adds to blowing them to the center, overloading the center of the mixer and wasting air at the edges of the combustor. This would not be a problem with your design. You might be able to use two or three of theses mixers side by side to gain a clean higher fire power.
The concentrator ring is intended to mix the wood gas and air, and the Venturi mixer is intended to mix the wood gas and the air, so you have a duplicate mixing system. I am not saying good or bad, just something I notice.
I see Julian has expressed some doubts about the Venturi concept. Good for him. I would be very happy if someone with adiquate equipment and technical ability proved or disproved the TLUD Venturi concept, either way. I perhaps will have to bite the bullet and buy a manometer with the ability to measure down to .001 inch of water column. My rather primative home made manometer did show a slight pressure drop at the mixer, but not enough to get any measurments. Our local college science department didn't seem to be interested.
Attached are some photos of the primary control valve I am currently using very successfully. It looks like something similar might work for you.
Good work Roberto,
Kirk</pre></div><div style="font-size:12.8px">"</div><div><div class="gmail_signature"><br></div></div>
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