Dear Jonathan and All: Very interesting observation that the upstream facing jagged holes almost completely blocked the water (air?) flow, while facing downstream they functioned better (but not good).
I'm very sensitive to this, having made an elegant natural draft pellet/wood stove from a 4 1/4" diameter by 6 3/4" high Dole Pineapple juice can. I'll report on the tests later. However, I drilled 12 1/8" primary air holes an inch up from the bottom (to allow combustion to stop well above the bottom) and 12 3/16" secondary air holes 3" below the top. I used the can lid to make a draft enhancer/pot support. I drilled these 24 holes using a step drill that has many diameters in increasing steps. (If you haven't got one, get it at Harbor Freight). But, I noticed some jagged metal on the inside and took long drills and waggled them around in the holes until they were smooth inside and out, since this was a research project. (Results to be published when I digest them.) I tested the new stove with pellets. Big mistake. They burned for 2 hours, mostly at a level of 1600 watts, as tested by observing rate of weight loss on a digital scale. (1 g/min of biomass combustion generates 20 kJ/g or 333 Watts. I was burning about 5 g/min. The stove held 600 g of pellets.) More to come when digested... TOM REED Pyrologist On Fri, Oct 1, 2010 at 9:00 AM, Jonathan Otto <[email protected]>wrote: > > > > *Report (written while flying at 4,235 feet above sea level over Lake > Victoria --I’m looking over the pilot’s shoulder -- in a Cessna 12-seater en > route from Bukoba to Mwanza), of a minor observation made in the shower.* > > > > When I tried to take a shower in our little hotel last night all the water > ran out around the edges of the shower head rather than through the holes > provided. Thinking the holes may be clogged, I unscrewed the unit -- which > looked like the spout for a local tinsmith’s handmade watering can -- and > popped off the flat perforated disk. > > > > It turned out the holes were not clogged at all. The holes had been made > with a punching tool and then the disk was inserted upside down, so that the > jagged edges of the holes faced up towards the stream of descending water > while their smooth side was facing downward. In layman’s terms, it seemed > that the water had no time to find its way around the jagged edges and > through the holes before the pressure forced it out of the showerhead around > the ill-fitted edges of the disk. I flipped the disk over, reinserted it > into to the unit, screwed that back onto the supply pipe, optimistically > turned on the faucet marked hot and voila! – fine streams of rather tepid > water spouted from every hole. > > > > Of course, flows of water and air behave very differently; however, as the > ever-colder water washed over me I wondered: would it make any significant > difference in the performance of the J seed TLUD if the secondary air holes > were punched with an awl instead of drilled. The dimpled rim on the exterior > side of each hole might slightly speed up the air inflow bending to enter. > The slightly protruding and perhaps slightly irregular inner rim of the > holes might create a bit of additional turbulence. > > > > Then I wondered if holes of various diameters would cause air entering the > chamber to behave differently and cause some more turbulence. Next thought: > if punching holes had no positive impact on air intake, can we determine > that there is at least no *negative* impact of punched air intake holes. Why > worry about that? Because producing all the required holes at once in a > piece of sheet metal that is secured to a purpose-made punching jig may be a > reliable way for tinsmiths to rapidly and accurately reproduce the winning > design of the ever-evolving Seattle J seed stove. > > > > On the other hand this bit of random cogitation whilst engaged in daily > ablutions may simply be a fine example of why some people make/test/perfect > stoves, and others trudge through their so-called careers as development > bureaucrats; and why I, who seem ensconced in the latter category, should > stick to writing the great American funding proposal so we can disseminate > the ingenious cooking appliance soon to be produced by the Seattle J seed > stove team. > > > > Over two youse guys, > > > > Jonathan > > -- NOTE: PLEASE CHANGE MY ADDRESS TO [email protected] Dr. Thomas B. Reed The Biomass Energy Foundation BEF, BEC, BER _______________________________________________ Gasification mailing list [email protected] http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org http://gasifiers.bioenergylists.org http://info.bioenergylists.org UNSUBSCRIBE HERE; http://listserv.repp.org/mailman/listinfo/gasification_listserv.repp.org
