ElfN
New Member
Posts: 9
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Post by ElfN on Nov 18, 2010 12:17:08 GMT -8
Has anyone here used a rectangular riser? I think I can score some 3/16" thick 8"x6" steel tubing.
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Post by canyon on Nov 18, 2010 21:00:23 GMT -8
I don't have experience with that material for a heat riser but I have used a lot of that dimension material for other things (such as a downdraft feed tubes or structural columns) and it is handy. In the book there is a drawing showing how round is more draft efficient for area (pg 32) and round well casing sections are somewhat easier to find (at least here) so I personally wouldn't use the rectangle tubing for a heat riser unless that was all I had.
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ElfN
New Member
Posts: 9
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Post by ElfN on Nov 19, 2010 5:58:37 GMT -8
Finding 8" well casing for a riser is proving to be an issue. I can get the 6x8 fairly easily so I'll do testing to see how it works. I'll try it in both orientations.
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Post by Donkey on Nov 19, 2010 8:48:57 GMT -8
I imagine that the rectangular tubing will do just fine. Where things might get a little strange is in figuring system size.. The cross sectional area of your tubing is 48 sq inches.. The area of 8" pipe is 50.24.. It's close, and there may be no issue at all.. OTOH, if you have a long bench, there may be a pressure mis-match causing backup.. ?? Play with it and let us know.
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ElfN
New Member
Posts: 9
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Post by ElfN on Nov 20, 2010 7:46:38 GMT -8
When Wadly gets me a chunk, I can play.
The area for an 8" round is 50.265si. The area for an 8x6 rectangle, taking into account the 3/16 wall thickness (7.625*5.625), is 42.89si. Not close. Even less close when you remove the area of the rounded corners. Closer to 40 than to 42, I would calculate, which puts it even farther away from the area of the 8" round.
Close is 7" round pipe (3.5*3.5*3.14159) at 38.48si. Closer by half.
I have a bunch of things I want to test with the 8x6 tube. One is the air flow between the tubing's long side faced to the burn tunnel and the short side faced to the burn tunnel. I won't get a chance to play once the stove's in place, so I'll have to do it before.
For the rectangular riser, I also want to test wide burn tunnel versus tall burn tunnel.
Has anyone employed an air flow meter during their testing?
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Post by ronyon on Nov 28, 2015 22:18:22 GMT -8
How did this turn out? My son wants a rocket forge ( as do I) and even heating along a fairly long area would be great for that, so I was thinking either a baffle plate at the top of a conventional riser, or a set of rests at the top of a .rectangular riser.
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