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Post by satamax on Oct 18, 2015 11:55:44 GMT -8
Well, all the pics have disappeared from the server i was using. They are all back up at permies. permies.com/t/44806/Cobbling-workshop-heaterIf ever i feel like it, i'll check way back machine, and re post the permies ones, in the right post. But that would take forever!     Well, gathered some materials in the happy chappy thread. Now i'm starting to use thoses. This is going to be the second bell at 6.35m² of isa. Will be covered in recovered bricks. From the inner wall that i have smashed up. Thoses bricks are hollow, and will be filled with concrete. I'm wondering if i should put a bypass from this bell to the chimney, on top. Or if i should do it in the first bell. System size gonna be 22cm. This vane is 25cm diameter. But it gonna feed into a 20cm chimney. Tho, that chimney is square'ish. I hope everything will be all right. Parts are going to be extremely tight! |
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Post by satamax on Oct 19, 2015 13:04:23 GMT -8
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Post by satamax on Oct 20, 2015 12:07:36 GMT -8
Repost from the bottom V secondary air! Yeeee fucking hell haaaaaa! This is a cross between my two systems, the current one, and the future one. Can you imagine a 18cm square heat riser. With a weird shape uninsulated batch box, and V bottom secondary air. Running a 8.21 ISA all metal double bell? Here it is!  I'll post the same message in the other post about my new build! You just can't immagine how chuffed i am. That exceeds previsions. A 7 incher, supposedely could cope with may be 8m² of massonry single bell. Here i'm in double bell mode, with all bare metal arangement. Madness, i tell you/ About 8m high chimney. And 20x20 sqare with rounded corners. |
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Post by pinhead on Oct 20, 2015 13:03:23 GMT -8
Chuffed?
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dkeav
New Member
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Post by dkeav on Oct 20, 2015 16:46:13 GMT -8
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Post by Daryl on Oct 20, 2015 17:52:13 GMT -8
Did you say metal, Max?  |
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dkeav
New Member
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Post by dkeav on Oct 20, 2015 18:04:41 GMT -8
Did you say metal, Max? Haha, get him! Rabble rabble Refractory!!  |
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Post by satamax on Oct 20, 2015 19:20:34 GMT -8
Well, sorry girls and boys, but the core of the batch is all refractory. Well, showing it's age and exposure tho! But it's mental!  Can't wait to have the new core on this! |
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Post by satamax on Oct 20, 2015 19:24:32 GMT -8
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Post by Daryl on Oct 21, 2015 2:20:06 GMT -8
Is the metal bell empty? What are the temps?
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Post by satamax on Oct 21, 2015 2:58:43 GMT -8
Well, sorry Daryl, i haven't recorded the temps yet  The big bell is empty and will be covered with the same bricks as the ones behind, and theses will be filled with concrete. Certainly stones on top, and poured concrete around the stones. For the moment i'm struggling making my concrete mixer work. And i'm wondering what kind of gap i should make around this inner skin. |
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Post by satamax on Oct 21, 2015 11:24:36 GMT -8
Fired it again tonight, and it was temperamental, for a little while, the stove would pulse slowly, like the J tubes when they are restricted, sucking the flame, then smoking back a tiny bit, then sucking the flame again, and so on. When the second bell was hot enough and the chimney too, it ran fine.
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Post by peterberg on Oct 21, 2015 12:17:47 GMT -8
Hi Max,
Just in the past 7 months it became clear the figures for the bell sizes weren't correct. My own cast refractory 6"/150 mm batch box single bell system is brought back from 5.4 m2 to 5 m2 and now it is finally willing to start up every time without a hitch. End temperature when started warm, last firing 12 hours ago, is between 80 and 90 degrees Celsius. We don't employ a bypass and since downscaling we don't prime the chimney anymore. Incidentally, the barrel tower in my former workshop happened to be the same size but was all metal. This suggest the difference between a brick bell and stacked barrels aren't that large, heat extraction-wise.
Together with the experience at the MHA meeting it's likely the size of a single bell for an 8"/200 mm system would be a notch less than 9 m2. Extrapolating that to a 180 mm system the top ISA for this would be 7.15 m2. So I would say your shop heater is oversized and is in need of a bypass. Probably you are getting away with it due the long straight chimney?
As a rule of thumb, I would say take 5m2 as the base and work out the rest according to the csa of the respective riser.
By the way, it might be getting even stranger. In Montana last week I've built a 4" Dragon Heater core into a 55 gallon drum. With the drum inside bare, it ran just fine although the vertical stack temp was a bit low. The next day we lifted the lid and stacked ordinairy red bricks on edge inside the barrel. When run, the whole system wasn't happy because the stack didn't warm up to something over handwarm. So the bricks were extracting more heat than the bare barrel, despite the fact the inside ISA of the brick liner was smaller.
Same thing with a 4" batch box system built into a salvage drum of 110 gallon. Ran OK with the bare metal and was unwilling to come up to temp with an inside liner of red bricks on flat. To make a long story short: Both were brought back to reason with a 100x5 mm/4"x 1/4" vertical slit in the stack which was inside the barrel just under the lid. Oh yes, the vertical stack didn't sport an elbow, instead it started 6" above the bottom inside the barrel and protuded vertically out of the lid next to the rim. Both of those set ups were attempts to create a small housing mass heater. Could be cooked on top as well.
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Post by satamax on Oct 21, 2015 13:20:07 GMT -8
Hi Peter. Not a daft idea the slit in the plunger tube. This thing will have all the bells and whistles to make it work fine. There's only one thing which bugs me, the chimney elements in pozzolan concrete cools down very fast. I think, since this side will be un accessable when the bell is covered in bricks. That i gonna fill all around the chimney with concrete and stones, and leave a door on that chimney, to to the sweeping. Which will serve as season start priming. I have another thing which buggs me actualy, i'm under the impression that the bell gets bypassed a bit by the gases. It doesn't get hot very fast. I might build a little "kicktail" wall in the bell. with bricks. I need your expertise, or expertise from the others, What kind of gap should i leave between bricks and metal? Can i use thick corugated cardboard to achieve that gap, and pull it or let it burn before closing the top? The core will be 220mm after. I won't keep this 7 incher. Not powerfull enough for the whole nearly uninsulated workshop. I can't remember, what is the guesstimate for power? 3kw gathered, for 1kg of wood? I think i can stuff in the 60 liters of the future firebox, something like 30 kilos of wood. 90kw! That's a monster I might be completely off! I'm still on the lookout for a door / top plate, to close the top of the future first bell. As i can't assemble the riser first and lower the bell on top. Something like the little door on the second bell, but bigger would be good. Enough to lower two 60l barrels to hold the insulation. As they seem near perfect for this aplication. The 220mm flue elements being 265 on the outside. And thoses barrels iirc are 37cm od. I will be completely short in ways of mass i think. 3.41 tons, may be! if the mix of low cement concrete, sand and brick can reach 2.4t a cubic metre.I can put a bit more around the pipes. I will have the firebox's base too and the first bell's top too. But nothing fantastic! If i could get a flywheel of two cold days, it would be better!  Btw, i'll top the firebox with a little 35x40 cast iron plate to boil the tea |
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jono
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Post by jono on Oct 22, 2015 4:47:56 GMT -8
Im trying to remember where I read about someone using corrigated card board to make an expansion gap around a heavy gauge metal riser surrounded by insulating concrete, or cob, not sure. as I recall, they just left the card in their, figured it wasnt doing any harm, or possably helped with some insulation value. I think they covered the card with a reasonably thin layer of plaster/clay or something, then let that harden, to prevent it from getting saturated and crushed by the big mix. sorry I cant be more helpful. donkey would know what to do
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Can't wait to have the new core on this! 
