Project: 170mm (6.7inches) ceramic batch box bed and cooker

[Orange]

well, it would be cool if J feed tube can be bigger than the system size. Than the batch box wouldn't be needed.

anyway, I've destroyed the floor tiles so I can put insulation:

[Orange]

some simplification to the design:

j-tube

[captainchaoss]

Forgive me if I misunderstand .... but wouldn’t the unit try to vent smoke back towards the feed tube, instead of thru the intended path ?

[Orange]

well the system should have enough draft to push the gasses. This is a bell system so there's less friction than the pipes system. And I'll add a chimney bypass just in case.

[independentenergy]

built in this way it seems that the task of heating the environment is entrusted to the bench and not to the bell, there could be the risk of a bench too hot.
a too hot bench could be annoying.
I would increase the size of the bell, which serves as the main heater and maybe I would make a bench with smoke channels.
moreover the bypass should heat at least half the system and not only bring the chimney to temperature

[Orange]

thanks for the suggestions.

if the bench gets too hot I'll just add more bricks or enlarge the first bell.

smoke channels add friction, I don't know if the system with 100cm riser is powerful enough to push trought tunnels.

i'm hoping bypass won't be needed.

[independentenergy]

Hi
in theory, the gas extraction from the bell is entrusted to the chimney draft.
the riser of the system j should take care to draw the flames into the horizontal tunnel and push them through the first bell.
what is found after the first bell should be at the expense of a good chimney.

[grga]

I can remember a few times I sleep on similar heater at my grandparents when I was a kid. My opinion is that it is interesting and fun but not to do it every day - I never had a good sleep. It usually is too hot and not soft enough. Did you try it somewhere, if not you should before making it. Just for room heating it takes less space and is more efficient if the bell is higher.

[Orange]

Dec 12, 2017 7:42:06 GMT -8 grga said:

I can remember a few times I sleep on similar heater at my grandparents when I was a kid. My opinion is that it is interesting and fun but not to do it every day - I never had a good sleep. It usually is too hot and not soft enough. Did you try it somewhere, if not you should before making it. Just for room heating it takes less space and is more efficient if the bell is higher.

it is a concern: donkey32.proboards.com/thread/2332/sleeping-on-rocket-beds

My idea is not to heat like 5 hours before sleep.

[Orange]

the 2mm steel sheet is not perfectly stable and rigid:





I'll try yasin's method with steel "L" profiles 50x30x5mm or similar. Bricks are 250x120x65mm.

[manU]

Hi Orange. Nice project! I have a couple thoughts that may hopefully help.
- with a chimney more than 4m tall, and vented "to the 4 winds" (higher than the top of the roof) I would be confident about draft. "H" on top helps. I would try to make it straight and avoid the 2 elbows, and think about an inspection/cleaning/priming door right at the base (4L metal paint container is what I use as cheap option). Remember pipe "males" pointing down inside the house to keep any condensation inside the stove, and the opposite outside to keep rain out of chimney.
- The bed: I would make a wall in the middle creating 2 bells, cover with concrete slabs and make the opening from 1st (front) to 2nd Bell accessible through the inspection door you planed at the end of the bench,so you can change the height of it by moving a brick up and down to fine tune.
- The core looks good to me, but if the heat extraction system works you can try different cores later. In my view a J is more suited for a cooking stove with heating capabilities, and a batch more for a heating stove with cooking capabilities... but this topic is very user related in my opinion.

Cheers

[Orange]

thanks manU for the suggestions, I'll definitely do some more tweaking. The bench is huge so the concrete slabs would have to big and heavy and high-tem resistant so that's why the idea with L profiles and bricks sounds good.

[Orange]

some mold has formed between the bricks and inuslated wood:



mold didn't form on a fully laminated wood on the left. Under the 2cm thick wood plates there is 3cm of polystirene.

my guess is temperature difference because the space is not heated and cold air cools the bricks while the floor remains warmer. Or the opposite   Any ideas?

[Orange]

Testing the 160mm j-core:



I like the minimalistic core design. 100cm long heat riser makes the proper sound and draft. Floor of the feed tube gets really hot - 5cm thick air-concrete under is not enough.

But the power is to weak. With the regular dry wood flames stay in the lowest part of the riser.

Batchboxes like satamax have the whole fuel burning which increases the volume of the flames and also secondary air shoots more flames in the riser:


Let me know your thoughts on J vs BB. Does your stove shoot flames trough the riser? Is it more annoying chopping wood for the J-tube or kneeling down to feed the BB?

[josephcrawley]

I would strongly advise against the j tube core. It is a very small fire to heat that much mass and will frequently smoke back into the house when the wood jams up in the feed tube. Because of this it can never be left unattended. The batch box will require a door which is pain to make or find but it is well worth it. Not really sure why anyone would build a j tube since Peter came up with the batch box.