Paul, first of all, have a look to a picture of a rotameter. So it is easier to explain:
http://www.electro-mation.de/schwebekoerperdurchflussmesser.html If you use a rotameter, you cannot use a fan to admit the forced air. You must have somehow really compressed air. The pressure must be much higher than the fracture of one mm H20 in a stove. The air is (variable) restricted very much before the air-column of the rotameter , so that through the measure-part of the rotameter flows nothing (when closed) or e.g. 100ml of air or 2 liters or 4 liters; as you turn more on or off these restriction. The rotameter column only shows you, (by a floating weight on the air- or fluid-column) how much air or gas or water flows per minute. In low tech, you could use a screw-clamp, which quenches an elastic tube. By doing this, the resistance of the burning-chamber is so small, that it nearly does not alter the pressured air-flow per minute. This system with rotameters was used in anesthesia-equipment, to have a continuos ( and/but changeable !) rate of fresh oxygen, N2O or air coming into the circular breathing system. This circular-system has always different pressures during artificial breathing -(by inspiration pressure plus; by exspiration pressure zero). Normally between 0cm H2O and 20cm H2O- column. It can exceed up to: say 49 cm H2O without altering remarkable the incoming amount per time of fresh oxygen or air or N2O. When you see these pressure-numbers, it is clear, that it would work in stoves as well, because the pressures are remarkable lower. I think if you could use pressurized air, a pressure with minimum 1 meter water-column (0,1 bar) could work. You could get an air-stream, which is _relatively_ not dependent from different resistance within the fuel-stack. If you would take an inflated inner car-tire (the bigger the tire the better ), good inflated, you had enough air with high pressure to feed a TLUD with primary air for a long time, without lowering the tire-pressure too much, giving a (nearly) constant air-flow. The flow-rate would be regulated by a screw-clamp, squeezing a flexible hose. - Behind that clamp you would have the a rotameter-column. But you can do without a rotameter: Bubble through that hose the air into water and fill a dumped, water-filled glass with these bubbles, to measure the amount of air. Count the amount per minute and regulate the bubbling to your wish/need. In this setting, you know the primary-air you get out of that hose sufficient exact. Naturally you must separate primary- and secondary-air. You could force the secondary air by a normal fan, if you want to have artificial draft. Primary- and secondary-air would be to regulate each practically independent from the other. The most important is, that you know the amount of primary air, and so you know the primary-air per square-section. -And that is the point you want to change in the system, because different primary air gives the different amount of produced "smoke"- You can adjust the TLUD-burn as you want, to look for its best performance. -And you get to know the numbers when it best performs. Mind: measuring the primary air-pressure does not give you the air-amount-numbers you want (or better you must have ) to know. You must know the flow number according to the square-section and look to the performance. So you get to know the right amount. At the end rises the simple question: How many liters primary-air per minute per square-section needs a TLUD for excellent burning? Regards Martin Am 07.05.2013 um 17:18 schrieb Paul Anderson <[email protected]>: > Martin, > > Where would you place the rotometer? Most fans / blowers create > back-pressure (and back flows) that do not go to the fuel stack? > > I do not have experience with nor possession of a rotometer. For this I > also need guidance. It would be nice to include this in the experiments at > Aprovecho Stove Camp this summer. And there we can also do experiments > with different layers of fuels. > > Paul > > Paul S. Anderson, PhD aka "Dr TLUD" > Email: [email protected] Skype: paultlud Phone: +1-309-452-7072 > Website: www.drtlud.com > > On 5/7/2013 2:22 AM, Boll, Martin Dr. wrote: >> Paul, >> >> I do not expect to get much energy, but the performance would be >> interesting. Even if there is different rate of mixture in different layers >> of the TLUD, you could get different outputs, and do that in mind the needs >> of the cooking-proceedure. >> Upper layer charcoal, to get ignition without smoke, than fuel with few >> charcoal as space-filler, than charcoal with (one have to experiment the >> rate of fuel/charcoal) fuel-bits, possibly a sort of raw saw-dust. And at >> the bottom just some charcoal to finish without smoke. >> If you allow only the amount air liters per minute to pass the rotameter >> and so the TLUD-primary (naturally you have to separate primary from >> secondary.air) >> you know exactly the rate of air. You have to calculate the free space in >> order to get the real air-speed in this area. >> I think even if that is naturally not the true surface-speed on the fuel, it >> is a good number to deal with. >> Even if you don't have the right number, you could calculate from one >> good-working TLUD to another which has a different Square-flat. >> Mind: The high of the fuel stack does not count, because the flow-rate is >> limited by the rotameter and not by the fuel-stack, because you work with a >> relatively high pressure and the flow is limited by the high resistance >> regulated by the rotameter. >> >> Little bit in hurry-. >> >> Regards >> Martin >> >> >> Am 07.05.2013 um 04:35 schrieb Paul Anderson <[email protected]>: >> >>> Martin, >>> >>> Concerning "space fillers", I and probably others have put wood chips and >>> small pieces into TLUDs where there is otherwise too much space between the >>> main biomass fuel pieces. Yes, the chips do pyrolyze. >>> >>> But my point is that making small pieces of biomass for filler can be >>> difficult. But using char pieces from previous TLUD batches is very easy. >>> But just do not expect to get much energy from the charcoal filler, >>> because it has already been pyrolyzed. >>> >>> Concerning your comment/question about measuring the flow of primary air, >>> it is not sufficient to measure characteristics of the fan/blower/pump >>> because the holes in the bottom of the TLUD are intentionally small and the >>> fuel is intended to (expected to) block some of the flow. What is needed >>> is to measure the flow INSIDE the fuel cylinder, such as in the bottom 2 cm >>> of fuel. But how to do that? >>> >>> Paul >>> >>> Paul S. Anderson, PhD aka "Dr TLUD" >>> Email: [email protected] Skype: paultlud Phone: +1-309-452-7072 >>> Website: www.drtlud.com >>> >>> On 5/6/2013 3:56 PM, Boll, Martin Dr. wrote: >>>> TLUD-ers turn it as you want; >>>> Charcoal as space-filler means __somehow__ that "mixed fuel" is used in >>>> a TLUD. From that aspect it is a "hybrid-fuelled" TLUD. >>>> Change the ratio of the "hybrid-fuelled" TLUD to: wood-pieces as >>>> space-filler (by charcoal-packing). Run this different mixture and look. >>>> Who did this already? Interesting to hear about. >>>> - It would be as well interesting to know the difference in performance >>>> between test-runs with natural draft and with forced air. >>>> >>>> Even by that different ratio, the burn can be stopped after outgassing, to >>>> get as final result charcoal. >>>> >>>> - Hybrid-fuelled TLUDs would get probably a better quality of resulting >>>> charcoal ( Frank, mentioned that as important difference for bio-char) >>>> >>>> P.S. We could stop guessing about the amount of more or less _primary air_ >>>> (caused by the minimal pressure of a fan or natural draft in >>>> different-dense TLUD-packages), and make an exact air-dosage by a >>>> rotameter, or less expansive and simpler by an aquarium-air-pump. >>>> >>>> Martin >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> Stoves mailing list >>>> >>>> to Send a Message to the list, use the email address >>>> [email protected] >>>> >>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org >>>> >>>> for more Biomass Cooking Stoves, News and Information see our web site: >>>> http://stoves.bioenergylists.org/ >>>> > _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
