Batch cookstove with a small riser

[Deleted]

Peter,

Thanks for your answer,

I now starve the embers every time at the end of a firing. I normally make two fires a day and with the starving technique there are always coals that are lighted again 8h after the previous fire.. so if I put small wood on it, it will ignite by itself. It's very very easy.

BUT the thing is that if I make a top-down lighting the fire will grow from both ends and there will be a massive amount of pyrolysed gases too soon in the burn, no ? Or maybe I'm afraid for nothing..!

Regards,

[peterberg]

Hmmm... In my case, the glow of the embers is generally down and out when I light it after 8 hrs. I would suggest you try to leave the embers to glow a little longer before closing and start top lighting the next time whether or not the coals are completely black.

[Orange]

yasin, how's your steel T-profile in the bech holding up, any bending due to high temperatures?

[esbjornaneer]

Dec 29, 2017 6:59:13 GMT -8 Orange said:

yasin, how's your steel T-profile in the bech holding up, any bending due to high temperatures?

And did you wrap it in ceramic blanket?

[Deleted]

Thanks, Peter.

Orange there where two L-profiles and I can't see anything inside but there is no cracks outside or anything yet.

esbjornaneer I don't use ceramic blanket inside wherever there's a contact with the smoke because last year I made a build with the riser being surrounded by superwool and now the superwool is half gone.. I suppose it's because it's bio-soluble..

Regards,

[Deleted]

Hi everyone,

As my last work of this year, here is the plan of the new version of the cookstove !

First trials will be at the end of January. Some modifications will be tried, mainly to add more internal ISA and to modify the riser, but the essence is there.

Part of the plan is to have the bricks pre-cut in the firebrick factory, so it will be sold "in kit" with the metal work sold separately. I hope to build them as a mason as well.

The construction of the cookstove requires 210 refractory bricks 220x110x60 mm and 6 lintels 600x110x60 mm. This represents 730 kg. With the metal work it's around 800kg.

The power on two full firing a day is 2500W BUT I've no doubt that is it possible to make 4 loads (or even more) a day without losing much efficiency. As a trade off, there is much more convection with this cookstove than with normal mass heaters.

Lots of compromises everywhere in this build :

The firebox is not as high as the Peter's specs, but it respects the volume of the firebox. That's because I took off the triangles.
The riser and the small bell above are mainly the results of the tweakings of this month.
Combustion results are not as good as Peter's standard batchrocket, but still excellent in my opinion.
The opening of the small bell is on the left because I saw by tweaking that the symetry of the double vortex was linked to the position of this opening.
I try to lay the bricks inside the heater to respect hydraulic Tichelmann's rules.
The cookstove is larger than the first version so that it could be a true double skin. It's made to be used with 50 cm long logs.
No glass on the oven's door because the other one was always full of soot.
They can be a ceramic glass of 340x350x4 mm replacing a metal plate, so that there will be the view of the vortex.
The metal plates for the plancha (8mm thick) and the oven door (5 mm thick) are plasma or laser cut. They can be cut with an angle grinder but with difficulty.
The insulating firebricks in the riser are JM26 flame-resistant or equivalent. They need to be cut in halves. They can be replaced easily.
The mortar is REFRACOL 240 (hydraulic and ceramic setting mortar) or something equivalent.
Dilatation joints are made with SUPERWOOL 607HT, 13 mm
Glass/metal joints are made with a self adhesive 10x2mm flat ceramic joint
Door joints are made with 12-15 mm (depends on the rigidity) round ceramic joint
The slab at the bottom of the cookstove can be concrete or aircrete (siporex or ytong). If you want some heat to go down then use normal concrete.
The closing valve is just a 5mm disk welded on a diam. 12 mm handle. There is only one hole of 13mm in the tube. The disk is blocked in any position because there is only one hole so the self-rotation is not possible. When you want to close the valve, you pull it a little bit to get it in the good position. It's been working well on the previous version.
The two thermometers are made for bread oven or BBQ and are sold on this link.

That work is released in Open-source CCBYSA4.0 (creativecommons.org/licenses/by-sa/4.0/deed.en) Please read it carefully.. It's mainly based on the batchrocket work by peterberg , but also great inspiration and advices from matthewwalker , Vortex , pyrophile and others as well.

The sketchup plans :
uzume-asso.org/assets/docs/experiences/cuisiniere_2500W/batch165_sidewinder_cuisiniere_V3-1.skp
uzume-asso.org/assets/docs/experiences/cuisiniere_2500W/batch165_sidewinder_cuisiniere_V3-1_sketchupV8.skp

Pictures :





Regards,

[esbjornaneer]

Great work Yasin!
When comparing the fact that your oven door sooted up and the glass at the front of Peter's DSR top box/tunnel did not, why would that be?

[peterberg]

The hottest point in the afterburn area is very close by, so the soot that's formed initially on the glass front will burn off later in the burn.

[esbjornaneer]

So Yasin's oven glass is in too cool an area?

[peterberg]

You could say it another way: the top box of the DSR is waaaay too hot for an oven appliance.

[esbjornaneer]

So you would say that there is no point in having glass in a black-oven door in any rocket stove where the oven is beyond the placement of the DSR viewing glass?

[peterberg]

The problem with you, my dear Esbjorn, is that every answer you get spawns new questions. I am actually surprised that it's just one question this time. To the point: I answered your former question and what you ask now is actually a conclusion.

I am really puzzled why you want the conclusion to be confirmed, since what you say above is an extension of the answer and as such the same. I find this behaviour irritating, the more you doesn't seem to have built anything at all, so there's no real situation to refer to. Probably you are one of those people that keep asking as the main occupance without doing anything else, there have been quite a few on these boards like that.

But to set your mind at ease: yes.

[esbjornaneer]

Thank you for your answer Peter. Isn't that what they say about science it produces more questions with each experimet/answer? (Don't bother answering, it was a retorical question.)
I am not sure that the search function of the forum is working properly at the moment as I am unable to find the thread in which I received help with my first build to refer you to. But you can still find the pictures here. It took place in 2015. And in the V2 folder following the link is my second build for which you kindly helped me sort out the by-pass damper. I have not got around to publishing the second build and did not create a thread for it as did not have more questions than about the damper. There is no reason you should have remembered either of the stoves.
And the 'real situation' I am refering to is visible here where the oven door glass is situated level with the top of the heat riser but it must still be too far away from the heat of the afterburn as it gets sooted up unless I overfuel the BBR. The fictitious (as in not yet realised) situation I had in mind is the DSR cookstove drawings I made and offered in donkey32.proboards.com/thread/2422/double-shoebox-rocket-cooker-oven?page=1&scrollTo=26648
But none of this information should really be in Yasin's thread... it only is because you inadvertently asked me for it in your previous comment to me.

Edit: the search seems to be working again. This was my first build in 2015 donkey32.proboards.com/thread/1901/bbrmh-oven-batchbox-rocket-heater

[Orange]

Yasin, your box seems to be different from the standard measures but I'm glad it's working properly. Have you thought about insulating the firebox, maybe there would be less coals and the burn would be cleaner? Also the cookstove can be higher like 100-120cm, that would give you more room for a riser or elevating the firebox for comfort.

[Deleted]

Hi Orange,

I think you're reffering to the version that I have tested until now.

The figures in your sheet are not exact. Mine are much closer to the standard specs. : the firebox height is 380 mm and the width is 240 mm. I measure the height of the port from the top surface of the horizontal part of the floor channel. The height of the port is then 290 mm.

I didn't want to insulate the firebox because all the insulating firebricks I know of are not abrasion proof at all.. and I don't want to compromise on that.

And how performant do you want to be, combustion-wise ? I think we can get cleaner by tweaking the riser and the bell, but it's not my top priority. Compared to any other cookstove I've seen (finnish style) the combustion here can only be much much much better !

Concerning the height of the cookstove I find that 100-120 cm is quite high if you cook on it. The first one I made was nearly 100 cm high and it was a little bit too much for the users who where 165-170 cm tall. 90 cm is standard.

Regards,