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Post by exoplasmic on Oct 11, 2015 5:11:59 GMT -8
is the entry and exit into the bells at same levels in your picture? Yes What is your system size? 8" perlite clay and refractory mortar. Daniel, what is you ratio of perlite to refractory mortar?
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Post by exoplasmic on Oct 11, 2015 5:14:55 GMT -8
$3750 This is more expensive than I first realized. I don't think I could have gotten approval from my wife if I said it was going to cost this much.
Chimney 2800 Bricks(refractory) 200 Claybrick 100 Castable 146 Castable 150 Mortar 45 Mortar 50 Trowel 10 Mixer 10 Chisel 10 Blades 75 Metal 15 Tube 20 Glue 5 Stove 100 Strap 10 TOTAL 3746
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Post by daniel on Oct 11, 2015 6:49:52 GMT -8
The refractory has only the role to be a binder here so you should use a fire resistant binder until everything holds toghether, I know all the receipes for clay perlite call for little clay but I have started with some micronized clay and some refractory mortar which I have mixed with expanded clay and perlite in a wet concrete consistency. I wanted to make it thicker but I did not want to open another bag of perlite. Because I poured this mixture between the riser and the stainless steel tube I figured it will slowly loose water and dry. I will fire it very very slow during several days to get rid of the moisture. I have about 10cm of this insulation around it.
I am now at the heat accumulation part and can't decide whether to do a one bell or two bells. I have some space constraints and I am not sure how to make my second bell. I also have a 8" system.
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Post by dustylfc on Oct 11, 2015 10:28:27 GMT -8
2800 for chimney!! Wow that's shocked me but that's a huge part of the budget I suppose.
Am lucky in that regard mine is going outside so no need for such a large chimney
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Post by shilo on Oct 11, 2015 16:04:44 GMT -8
in RMH you can use tin chimney. there is no real need for a gold one.
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Post by exoplasmic on Oct 12, 2015 10:29:31 GMT -8
Yep, chimney was overkill on quality and price. It has double walled pipe. The inside is black pipe and outer pipe is stainless steel. It's 34 feet (10.36 meters). $900 for labor. $1900 parts.
I don't feel good about the cost (to say the least).
Learn from my error!
But on another note: if my system fails, I can't say the chimney isn't high or insulated enough.
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Post by exoplasmic on Oct 12, 2015 10:40:31 GMT -8
Another note about wood burning in general.
A lot of people stop burning wood because of the hassle of finding wood, spitting it, storing it dry, and staying smoke-free. I hope the smoke in my house is minimal or non-existent.
I know two people who have discontinued burning wood because of the intermittent smoke issues. The smoke was causing respiratory problems. Both families burned a lot of wood. One family relied on it almost exclusively to heat their home. Smoke was leaking out sometimes when they opened the door to add more wood.
I hope I never have to open the door when the fire is going. With one or two batch burns per day, I'm hoping that I minimize any exposure to smoke, that otherwise that seems inevitable.
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Post by dustylfc on Oct 12, 2015 10:47:10 GMT -8
Am hoping it will roar soon as you light it and am sure it will draft very well with that chimney
I did a mock up yesterday of a batch box no measurements just tinkered with bricks to form it's similarity and I was either extremely lucky or the batch box just works great whatever the dimensions
It was outside not even air tight just loose brick and it was a real pleasure to see it work almost as it should this of course was just an experiment
What I did do though to get the wood burning was placed the wood inside the batch in the shape of a rocket stove and I don't know whether it's Been done before but it burnt excellent with wood that was damp it was an interesting experiment for me it was as they say rocketing
If you don't get what I mean with the wood arrangement I stacked the wood with a horizontal channel on base of batch just like a j tube and stacked wood on top of this channel I then set 1 piece of paper in the channel with some smaller bits of wood and left it Maybe this could be done with normal log burners it burned for quite some time
Anyways we want more pics heheheh
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Post by dustylfc on Oct 12, 2015 10:50:38 GMT -8
On any smoke issue I think the concept of the batch box is to let the loaded batch burn out before loading another but with the size of your chimney am sure the draft will be greater to stop any back smoke
That's only my guess I could be wrong
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Post by exoplasmic on Oct 14, 2015 17:33:20 GMT -8
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Post by exoplasmic on Oct 16, 2015 14:15:14 GMT -8
I may have 11.5 inches above the top of heat riser. Here is a picture... www.dropbox.com/s/ak2jc93t0o9ksia/2015-10-16%2017.48.50.jpg?dl=0Will this be enough? I could go another 5 inches, so I'd have 16.5 inches of open area above top of heat riser. The top will be a slab of refractory (castable) about 3 inches thick. On top of that is going to be 1 inch of ceramic board that is very friable and breaks easily. It is 12x36x1 inches. Then the very top might be square sheet of metal, mostly for dust protection. That would put it very close to PVC pipe.
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Post by dustylfc on Oct 17, 2015 14:47:00 GMT -8
Am pretty certain Pvdb batch had 12" above the riser am not completely sure if it makes any difference I would ask Peter himself or max they seem the most likely to help
Though I'd like to add I carnt wait to see you fire it up
Goodluck
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Post by exoplasmic on Oct 17, 2015 17:38:51 GMT -8
Thanks Dusty lfc. I think I'm going with 12 inches above heat-riser. The hot gases can expand at least 4 inches on all the sides too. It shouldn't be too restrictive to the flow of exhaust gases. Mike
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Post by satamax on Oct 18, 2015 0:29:40 GMT -8
Mike, i think the 11.5 is plenty good enough.
Tho, i have a concern. If you have an angle grinder with a diamond wheel, round the two edges leading into the down flue, i think that would be better, the less turbulence the better.
Regarding the top gap, i know for sure i can go much smaller. Tho, with a very tall chimney. Here what worries me, is the 180° bend the gases have to do, while hot and expanding. I'm not sure how much they realy expand. With Karl, we had an argument over this. He was saying that at ambient presure, gases are not realy expanding much with heat.
But restricting the downflow of the gases as you have done worries me a bit. I like the idea of a barrel or bell, where the gases have room to flow down. Mind you, i might be completely wrong. And you will have discovered a new way of doing things.
Anyway, now you are bound to bite the bullet.
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Post by exoplasmic on Oct 20, 2015 13:09:43 GMT -8
PV=nRT. If you increase the temp by 1% you increase the volume by 1%, all other things kept constant.
The 180 degree turn is over 4 inches as measured from edge of the heat riser to edge of the down tunnel. The down tunnel cross section area is 67.5 square inches. Compare that to the CSA of 8 inch tube of roughly 50 in2. I'm hoping that any mass of air has enough decrease in pressure (with slight increase in volume) to aid for the free movement of gases. A small decrease in temp would also aid the flow of gases too. Volume and temp are directly proportional.
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