Crispin,
This was the Stickwood Boiler by Richard Hill, University of Maine at Orono. In 1979 it was the highest efficiency wood burner that we had seen. I had the privilege of working with Dick on the First International Conference on Solid Fuel Appliances which we held in Portland as part of an effort to improve wood stoves. Dick was part of the group of us working on improved wood heating appliances in the 1970s that lead eventually to the EPA smoke tests and standards for wood stoves. See the pdf report on how to make it at: http://www.bioenergylists.org/en/node/117 The home boiler was produced commercially in Maine in the 1980s as the "Jetstream". Dick is now an emeritus professor at the university. http://en.wikipedia.org/wiki/Jetstream_furnace It really was a staged combustor. By inducing a draft through a small hole Dick created a jet that would impinge on the firewood creating a blast furnace effect. The idea was to limit air entry but create an airblast that would create high local turbulence and wipe the boundary layer of gases from the wood as it burned. The products of starved air combustion were burned out by introducing secondary air. His theory was that CO and O2 molecules could travel along in the gas stream and never react unless forced them to at high temperatures. It worked. Tom From: [email protected] [mailto:[email protected]] On Behalf Of Crispin Pemberton-Pigott Sent: Monday, January 24, 2011 2:25 PM To: Stoves Subject: [Stoves] Pyrolysing side draft stove, 1982 Dear Friends Interesting set of features on this stove: <http://www.freepatentsonline.com/4309965.pdf> http://www.freepatentsonline.com/4309965.pdf It looks like it is a wood-pyrolysing sidedraft gas-burning concrete-lined combustor attached to a water heater. It claims to be creating pyrolysis gases, feeding them sideways from the bottom of the hopper together with (fan-driven) secondary air creating a flaming zone separate from the combusting/pyrolysing biomass zone. It does this in a very restricted primary air environment and burns whole logs. It can be refuelled continuously because the fire is on the bottom of the chamber. It makes frequent mention of refractory materials cast in situ and the complete burning of the gases. Another one might be of interest to the jatropha cake burners: <http://www.freepatentsonline.com/1469600.pdf> http://www.freepatentsonline.com/1469600.pdf It claims to be able to burn duff coal (small, to dust). Maybe with a wire grate instead of the cast iron shown. Note that it has an updraft channel for getting the fire started. Many stoves this size have such a feature. It is often re-invented as a solution to the difficulties faced getting downdraft stoves started. Regards Crispin
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