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Post by AlexHarpin on Oct 3, 2014 16:11:41 GMT -8
I filmed the flame escaping from the top of the heat riser in the most intense moment of combustion. I'm no expert but I think it is very hot.
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Post by satamax on Oct 3, 2014 22:44:45 GMT -8
I think you're lacking insulation
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Post by AlexHarpin on Oct 3, 2014 23:38:05 GMT -8
You think so? Yet this insulating bricks is good for supporting up to 2800F and it was not really warm to the touch, wouldn't be rather the fact that there have no mortar between the bricks and there could be a leak of seal? I'll be sure to add a ceramic blanket during final assembly. However to my eye, the heat riser seem shorter proportion in your video.
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Post by satamax on Oct 4, 2014 1:12:37 GMT -8
may be you had less wood
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Oct 4, 2014 10:29:42 GMT -8
Alex I would have to agree with you. Your leaky riser isn't helping things. Once sealed it will perform better.
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Post by pinhead on Oct 8, 2014 5:53:22 GMT -8
As I will repeat my mold, I decided to make a version with the integrated P channel. Would it be a good idea to do it this way?
8,5" mould with P channel I believe Peter recommends the P-Channel being made out of metal so it absorbs heat from combustion, thus preheating the secondary air.
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Post by AlexHarpin on Oct 9, 2014 17:58:05 GMT -8
Thank you for the tip! In this case I'll built it out of stainless steel as assumed.
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Post by ericvw on Oct 9, 2014 18:12:41 GMT -8
Hi Alex, In my current test setup, I used what I had on hand-mild steel, and after 2 months, no problem. But I do have a stainless steel version coming out of scrap at work- thing is, won't be tube, but 2 formed halves, welded. should do the trick... Eric VW
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Post by AlexHarpin on Oct 10, 2014 6:07:52 GMT -8
^^^
One of my client is a good tig welder, he is supposed to be able to make one for me.
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Post by AlexHarpin on Oct 17, 2014 10:34:19 GMT -8
In terms of bells, I thought I read somewhere that the second bell must have an internal surface area 35% smaller than the main bell, same for the third versus the second. Is that correct? How many bells could support a system of this magnitude?
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Post by peterberg on Oct 17, 2014 11:00:10 GMT -8
In terms of bells, I thought I read somewhere that the second bell must have an internal surface area 35% smaller than the main bell, same for the third versus the second. Is that correct? How many bells could support a system of this magnitude? A large system can easily support three bells. I am not familiar with that 35% rule, but there's something you should know before building such a stove. I've found out that a double bell is about 15% better in extracting heat. So a double bell should comprise a 15% smaller ISA as compared to a single bell. There are some signals that the triple bell is again a percentage better, somewhere in the range of 10% to 15% again. In short, the total effective ISA of a double bell need to be 15% smaller than a single bell of whatever shape.
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Post by AlexHarpin on Oct 17, 2014 13:12:22 GMT -8
Ok thank you Mr. Berg! It's more clear to me now , I misread and I was totally wrong with the 35% rule.
So if the internal surface area is approximately 129ft2 (11.9m2) with a single bell system, with three bells the ISA will be 89.7ft2 (8.33m2) ?!
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Oct 18, 2014 0:05:30 GMT -8
Peter, Alex calculated the ISA of his triple bell as 30% (2 x 15%) of a single bell ISA. Is this correct or should it be 15% of the double bell ISA?
Metric
| Calculated from single bell ISA | Calculated from double bell ISA | Single | 11.90 m2 | 11.90 m2 | Double | 10.12 m2 | 10.12 m2
| Triple | 8.33 m2 | 8.60 m2 |
Imperial
| Calculated from single bell ISA | Calculated from double bell ISA | Single | 129 ft2 | 129 ft2
| Double | 109.6 ft2 | 109.6 ft2
| Triple | 90.3 ft2 | 93.2 ft2 |
As you can see there isn't much in it, but would be useful to clarify this.
Andy
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Post by peterberg on Oct 18, 2014 0:21:03 GMT -8
Alex, this is not entirely correct. Deduct 15% from the single bell to a double bell, deduct 15% AGAIN from the double bell to the triple bell. That 11.9 m2 doesn't seem right, according to my calculation the 8.5" riser's csa is 2.07 larger as compared to the 6". We know 6 m2 is maximum for a 6" system, so an 8.5" system could (probably) serve 12.42 m2 as a single bell. That would be 10.56 m2 for a double version and 8.97 m2 for a triple version.
Mark however, this hasn't been done before so you are on the cutting edge. To be on the safe side, I'd recommend to install a bypass halfway the height of the first bell. Preferably not at the top, too darn hot up there.
Morty, our posts did cross but you are right regarding the method.
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Oct 18, 2014 0:42:19 GMT -8
Thanks Peter
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