Just something I found interesting, the first year using our wood furnace I was using a standard 6"double wall with a standard cap....the draft was ok but I did install a Draft Inducer and it did improve the draw....This year I finished up a custom concrete cap, it almost looks like a Chimney Pot Hybrid...four open sides with SS screening and maybe 5-6" to the underside of the top concrete cap. Since the new season I have not needed the draft inducer once....the draw is better, much better, wood is the same, everything is the same except the cap...I have no idea what the specific science is behind the cap I built, I certainly was not thinking about anything but the basics...just got lucky I guess..I have been reading and observing a lot about many different aspects of burning..on flue pipes and drafting i think the individual house, roof lines, Topography around the structure , orientation of the structure, neighboring structures all play a part in how well or poorly a stove or furnace will draft.....
Top Cap and draft...
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BoilerMan
Minister of Fire
This is interesting, I always thought that rooflines and how the wind comes off them has the most effect on draught. In some cases a cap can improve draught, where others it hinders.
I always figured if the chimney was the highest point of a structure it is ideal, and that a cap would have little effect on the natural convection in that column we call draught, other than diverting it sideways.
TS
I always figured if the chimney was the highest point of a structure it is ideal, and that a cap would have little effect on the natural convection in that column we call draught, other than diverting it sideways.
TS
BM, I don't know any of this for sure, but I do know what I am experiencing. The more I read about things like Gasification, Rocket Stoves, Syn Gas, Convection, Etc....the more I realize that there is a lot of things we don't know about fire....For example FEMA has a plan that I downloaded for building a Gasifier that will run a generator, the download is about 90 pages, I have just begun to read it...Likewise the Internet is full of people who attempt to improve the FEMA design because of the excess Tar and byproducts that the Gasafier produces, these BYPRODUCTS foul and shorten the life of any engine that they are running....Fire and the technology behind it appears to be a wide open field with many things left to learn......this is a good thing.....
velvetfoot
Minister of Fire
This is very interesting. I don't know if this could help with my problem of smoke order in the basement from a chase with multiple threads, so I'm going to start a separate thread.
BoilerMan
Minister of Fire
Those are cool, some on youtube running things.
I hope my tone didn't come across as not believing you. This is not the case at all, I was simply saying this is contrary to what I thought, and you taught me something.....always a good thing to learn!
TS
I hope my tone didn't come across as not believing you. This is not the case at all, I was simply saying this is contrary to what I thought, and you taught me something.....always a good thing to learn!
TS
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