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Post by rakettimuurari on Nov 18, 2017 3:49:05 GMT -8
Terve kustaa! I' ve been also pondering the sauna-stove construction options more than a year now in my head. It ends up being tricky like u found too. Riser heat cannot in my opinion be harnessed for stones as all the heat is needed in the riser for valid rocket operation and clean burn, however the heat coming from riser can be harnessed on the other hand. So probably during next summer I'll be going with batch rocket sauna stove inside of this kind of structure: www.ponttouunit.com/ponttokiuas/kuvagalleria-kiukaat/or google "pönttökiuas" So far I am thinking it would be only viable option. Stones would be inside refractory / firebrick cage just above the riser, behind the door. During sauna time (after fire has died) the door is opened and water is thrown on rocks inside. Greetings from Lempäälä, -Antti-
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Post by rakettimuurari on Nov 11, 2017 3:51:01 GMT -8
can you compare effects of damper vs closing the air inlet? for the oven, you might need some metal or chamotte plate directly above the riser as the baking surface, should get higher temps. Aye Orange; I will make comparison with the temps one day as I have finished all tweaking. The difference with damper is smaller than it would be with traditional contraflow heater; still at the moment I think damper adds 3-4 hrs to heat retention time. Damper is easier option as all the hatches except the fire box door are not gas tight. As for oven; I burnt two batches (in total some 6kg) directly in the oven itself first time yesterday. Definitely cleaned the black from oven walls but to my surprise the peak oven temp was some 10'C lower (195'C) than burning 10kg down there in actual firebox in the rocket. Also the heat load for the top part of the heater was much higher even with bypass open. So I decided to keep burning in actual firebox even for baking for the sake of heater's health and cleaner burning. Your suggestion for baking surface: will try something like that. The problem is the low height of the oven (23cm). At the moment I have added two firebrick splits standing on their sides around the riser inlet to the oven, effectively adding 12cm to riser height and same time forcing the gases from the riser shoot first against the oven ceiling. This seem to improve both the burn power and the oven temps. The splits can be then collapsed to the oven floor in the end of the burn in a case of baking as they are only 2,5cm high.
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Post by rakettimuurari on Nov 9, 2017 0:50:13 GMT -8
Damper installed
I punctured the chimney and installed the damper some 180cm above the heater's main chimney connection. I got bit worried as the chimney proved to be some 2cm narrower up there than it is in the bottom; little less than my CSA... I also installed the smoke gas thermometer at same height. Chimney temp proved to be some 65'C which almost made me bit scared, but... the draft is adequate and I have bypass in place. With the bypass open the temp was doubled to 120-130'C. It seems I am not heating the sky too much though... I just have a feeling that I ended up playing on the operational limits considering the relatively large ISA (have not made the exact calculation but I assume it to be somewhere at 7m2) and tighter than planned chimney but so far it has still been operating greatly. Moreover, as winter develops so will my draft, as usual. Observations in relation to below fed primary air
Lighting the batch from top is clearly not an option. Lots of smoke and painfully slow burn comes as a result. On the other hand lighting it from the bottom on the port side works like charm. I got the original very well working method from this video by Klemen. Lit like that the batch is in full burn in 2-3 minutes and very little smoke is visible even before that. Under air is efficient but seems to make the burn more vulnerable in relation of the fuel positioning. Most vigorous burn being in bottom it creates large cavities which then collapse later during the burn and in worst case may block the port (which usually in my case just seem to increase the strength of the burn...). So far this hasn't really been any problem yet. Care must be also taken in the beginning not to block the cast iron hearth covering the bottom inlet of the firebox when laying the fuel. I have been thinking the option to enlarge the air vent of the door to match per Peter's guidelines as I feel that it would provide more flexible and stable operation and enable the top down burn better. Now the CSA of the door vent is some 7,5% of the system CSA and is feeding mostly the floor channel and secondary burn. But if I am to keep the cast iron hearth for the embers to filter into the ash box below, then some cooling airflow also from below is required to keep the metal from getting ruined... On the other hand if I would manage to find feasible way to initiate fluent top down burn with the current set up, that would improve things too as fuel would stay more stabilized. I am still going to experiment still some more by giving air only via door crack and for a longer time in the beginning. About all this, your thoughts and feedback are appreciated! "The other tip I have picked up in the last year is that if you spray a fine mist of water over the bread before it goes into the oven it browns better/more.
Looking forward to pictures of your loaves when they come out, Esbjorn"Esbjorn: Thanks for idea; that would be even more crucial on this lower temp. I used to splash half desiliter of water to normal oven before closing the lid and that also worked but spraying would definitely be the correct option now. Regards, -Antti- Written in a cozy batchrockety room temperature of +24'C
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Post by rakettimuurari on Nov 7, 2017 11:59:44 GMT -8
OvenFor all that I would really appreciate community feedback and ideas! Hi, A little off topic but here we go. Here in Southern Spain we have a solar oven that seldom go above 180C, most days reaching about 175C. We also make our own sourdough bread, 100% rye. And bake it in that solar oven most of the year. It takes a long time to cook compared with doing it in a 250C oven but it gets done in 1.5-3hours, depending on how wet the dough is when going into the bread tins. So a question is how long your temp will stay up, about 150C? Below 120C it is a bit low but there are recipes online for 'slow baking' the same as 'slow cooking' like is done with meat. Great to read your thread stove looking good and seems to work a treat! Looking forward to updates, Esbjorn Thanks Esbjorn, for interesting info and compliments! Slow baking... ; I must delve deeper into that! Sourdough rye here too I am always just running after dark brown crust so that's why I' ve been using hi starting temps in electric oven - heat to 280'C; bread in and lower to 200'C -> 1 hour ... but this slow baking is something new and practical to test indeed! Temps have been poor to stay up; they will decrease under 120'C in 30 mins. While writing this I have my first oven modification in testing. I added one spacer piece into the oven ceiling. Basically i just added one more ceiling vault piece in the back edge of the roof exhaust in the oven. The piece is different to rest of the vault by being only 3cm thick and hanging 4 cm lower compared to the other vault pieces in the ceiling, thus forming a threshold for the gases to come around before exiting the oven. This way I am aiming to create a heat pocket in to the rear of the oven. I am also burning the record amount of wood for this stove so far - some 10kg. First 7 kg I did with the bypass open and the rest with the bypass closed, this all in order to avoid having sauna in living room. Shortly the embers are done and I will start to measure the oven temps. **Somewhat good news for the bakers; with my threshold piece in place and burning 1,5 batches (about 10kg) of wood I managed to achieve a temp of 210'C! Now the clock is ticking; lets see how soon it cools down... ***OK. After 1 hour there is still some 170'C in the oven! Esbjorn; I guess that will be very doable with the bread. My guess is that burning two full batches (15kg) would bring the thing to at least 250'C. ****Oven temp 2 hrs after the fire was bit less than 150'C. Ten hours later 70'C. I believe I will get still light improvement when I install the sliding closing damper in to the chimney stack. Later on I will burn two batches in the oven itself to see how it works, as I designed that option there too. It wont be so clean but it will surely heat the oven. Primary air comes through the riser and behind the threshold, secondary air from the door vents, in front of the threshold. I am planning to achieve secondary burn on the door side of the threshold just below the exit slot. Primary burn and wood is behind the threshold, in the oven rear. We'll see how it behaves. Cheers, -Antti-
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Post by rakettimuurari on Nov 3, 2017 23:26:35 GMT -8
First full batch and floor channel in placeIs there Boeing 747 in my living room? No... it is my first full batch burning! Floor channel was built yesterday and it still made great deal of improvement. Most visible/ audible change is in heater acoustics; now there is a distinctive higher pitched rumble which seems to originate from the heat riser; even if i decrease the primary (under-air) intake - secondary air is all open. I would assume that is a good sign; after-burner now seems to have its own life. Heating capability As for heater my expectations are already met. Total mass of 2500 kg and solid oven structure + support columns inside seems to give good heat reservoir. Surface is hottest some 5 hrs after the climax of the burn and top of the heater is not too hot to touch (except areas around firebox and oven) - estimated 50'C. After 12 hrs it is still warmer than hand and all this with some 6-7 kg of 1,5 years dried spruce cord-wood. What makes me even more satisfied is that this all is achieved with no chimney damper in place. If I would leave the same sized contraflow masonry heater of my childhood home with chimney damper open overnight after fire, there would be no warm walls in the heater in the morning. I would assume this is again one advantage in system with bell operation as most heat remains at top of the bell even when the airflow is free through the system after the burn. Moreover, now when the drying and break in is completed I am going to install the regular cast iron sliding damper close to the rooms ceiling level into the chimney stack, like we do here. By that, many additional hours are likely to be gained in heat reserving capability. Disclaimer: I know that many users in other "heating cultures" are against the dampers but here it is just the regular way of doing it and many of us here still grow up learning it. Gas tight doors have not yet became so regularas we have so much old masonry around. Two other things on top of the experience also adds to security: the notion that excessive amount of liquor and chimney damper is not to be used in the same evening and carbon monoxide alarming device (also quite regular here). Just want to say this with no any offence but I've had this discussion so many times It was -7'C here already two days ago so all available heat is welcome.
OvenOperation and the heat retention are not satisfactory for my needs yet. I would need minimum of 250'C temp for my bread. Oven cools down now quickly to under 200'C after fire is gone. My assumption is that hot gasses pass the oven too quickly for it to retain the heat. Heating and stratification of the gases in the system in general seem to work properly now so it is good starting point to start tinkering with the oven as the primary function is ensured. For all that I would really appreciate community feedback and ideas!My thanksI want to once again thank especially you Peter, for your rock solid, patient, persistent and analytical pioneering work and ever helpful straight to the point approach. It feels so easy to just come to your site, take the numbers and build something so useful, ecological and inexpensive which is already thoroughly tested. You have done huge amount of beneficial work which you share freely and it is certainly one way to make the world better. Same goes with all of you co-innovators who have done and are doing the same and adding synergy into the whole process. I take my hat off for you (inside the house still). I'd love to return the contributions in any useful way. I can share my slide show diary about the building process showing more of the inner structure of the heater; just send me message if interested. The sketch up plan is already in sharing; what would be the best way to share by the way? Also Peter, if you would need a Finnish translation for your site for added exoticism let me know ; we speak some kind of English here quite much but I already know many who would be interested about your concept being also masonry capable, but however would be stopped by the language...
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Post by rakettimuurari on Oct 31, 2017 3:55:32 GMT -8
- BREAK IN FIRES FOLLOW UP - Its my third day with cord-wood. The load is something like 2,5 - 3kg large. I am adding 1kg per day to the load. Two fires per day, separated by 12hrs. This was first day the walls got warm outside! Upper half of the heater is uniformly warm from all three sides after some 4-5 hrs from the fire. Little less warm than hand; perhaps some 25 to 30 Celsius (I don't have proper measuring device yet). Firing behavior stays good or has slightly improved. Bypass still not needed. Regrettably I am doing the break ins and drying fires without proper floor channel as I will be getting it only in one week. For now I have only the horizontal part of the floor channel/ secondary air in place. Under air requires that bottom wood pieces cannot be too tightly laid but other than that it burns with nice roar. Secondary air is obtained through the door vents. Ash box with cast iron hearth in the bottom of the fire box has proven excellent and handy. Only leftover is finely pulverized ash in the box. THE OVEN So far the small loads have not been able to heat the oven too much and it is not retaining heat for too long. the peak has been in 150 Celsius. Also the fly ash makes the oven quite messy which is not really big problem. I just loved the original beige look of the firebricks I believe this will improve with bigger wood load when the heater walls also start to be warm below the oven level. If redone, I would consider the possibility to exit the exhaust through the oven wall instead of the ceiling vault thus maybe creating the oven more bell like space ... I have extra refractory piece which is possible to install in oven ceiling in order to create a heat pocket in upper back part of the oven. We'll see. First full batch will be pyrolyzed during next weekend.
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Post by rakettimuurari on Oct 26, 2017 2:31:01 GMT -8
Hi again, Orange: It is 160mm; i was just lazy shaping in sketchup with irregular shapes. Riser is round. I installed both intakes for air (door and under) as I definitely wanted an ash box so the underair is experimental. If needed i will install a closing ash hatch and enlarge the air channels in the door. So far when burning a handful of kindling every morning and evening it burns like a furnace with underair open. Next week I'll start with regular cord-wood and gain more info. travis: My understanding is that it will work very similarly as long as measurements hold. "...The differences in firing behavior are fairly small so this will be a good alternative..." Info from here... I wanted the oven as I bake my own sourdough bread couple of times a week and u just cant beat the masonry oven in that... Most I am looking forward to see the baking behavior of the oven and the temps; about the rest of the heater I am quite assured already. White flame is just nice looking thing. So far i had no need to even use the bypass. My only concern about the heater operation in general is that will there be enough space for the proper stratification of the gases to occur. I used every cm I had whatsoever. Jura: All grey material in plan is castable refractory mass, also the vault (made from 3 pieces for flex joints). Orange is fireplace refractory wool plate (10mm around the oven and firebox; 50mm on roof). Roof refractory plates are supported by shaped regular bricks to omit roof corners gathering too concentrated heat and shortening the hang of the plates thus giving strength. **Curious thing about my chimney stack (from 1936) is that it is an half brick sized (ancient large sized brick) from heater on but widens up to be something like 1,5 brick sized in upstairs when another half brick channel from kitchen (exit air) joins it. That makes chimney constantly warmer than outside thus creating constant draft which again serves the heater very well. Just to open the heater damper 10min before firing and close the kitchen exit air does the trick. Today's regulations in Finland would not allow similar design
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Post by rakettimuurari on Oct 21, 2017 5:40:10 GMT -8
Hi again forum, At least my new batch rocket stands now! And thanks for your input orange! However I followed the original plan and now all is ready and I am waiting in order to let the heater dry. After two weeks will start with break in fires. I managed to keep minimum 10 cm opening on firebox and oven sides and back. Ovens support columns brought extra ISA so I went on with by pass installation (cast iron). According the old tradition I burned the plans/ drawings after roof was on place and draft was excellent. We'll see about the real operation... I enclose links to picture and sketch up plan. I left the slit on oven vault very large in order to ensure the stratification of gases. I hardly can wait to test the operation. Estimated final mass is around 2,5 tons. I will give detailed info as I start the runs in 2 weeks. Sketch up: drive.google.com/open?id=0B_O6G3ixIMfHbDFsQUdSdXpaenMPicture: drive.google.com/open?id=0B_O6G3ixIMfHT1c5RGFIdGNLaHMEnjoy the autumn; we got minus 4 Celsius yesterday early morning -Antti-
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Post by rakettimuurari on Sept 5, 2017 4:10:24 GMT -8
I want to have both - delayed heat transfer as well as powered one; so i thought i will go first with single skin but if room temperature is too high after a batch burned, I have been considering about adding the cover masonry afterwards. I am after clearly warm surface but also at least 12h storage, but I dont have math to count it so I thought to experiment. Single layer system (12,4cm) should have the highest surface warmth some 5,5 hrs after lighting the fire and cool down is probably affected by the mass? A very simple rule of thumb: every 100 kg of active mass provides for one hour of heat release. Some Finnish mason wrote that it would be better to have cover masonry thinner than the body masonry itself? What are your thoughts on that? All in all I feel its better to make it too hot/light first than too cold and heavy. The inner skin gets hotter than the outer skin, so more mass in the inner skin means a larger "hot storage". My heater is double skin, 12 cm inside and 5 cm outside. And yes, it's slightly slower and lower temperature than the single skin of 12 cm. The downside of double skin and lots of mass, if you prefer to see it that way, is the heat is emitted very regularly at the same power over most of the 24 hour cycle. As opposed to single skin which tend to emit in bursts that goes down to a trickle before the next burn. Somehow the firebox in 160mm BR still feels so small compared my current one so it was hard to think to have even smaller one... I was after max potential. You have made to rethink this however. I should not be too worried about the footprint though as I am quite sure the original heater has been really much larger. There's a thing about a batchrocket as compared to most heaters: all the fuel in a batchrocket should be loaded front-to-back, no campfire or log cabin style. So a load is fairly massive, with only small openings between the logs. A 150 mm system could accomodate about 6 kg in one batch of birch or beech. I could try to expand the area of the heater depth wise by adding maybe 10cm more depth to whole footprint. This way i could free the back wall ISA completely, the firebox and oven being entirely separate from it (not attached to it as in original plan). Do you think that only some 3 to 5 cm gap behind the firebox and oven would enable the free flow for gases? With this maneuver I quickly counted total ISA estimate would be around 5.6m2. Down-scaling system to 6" could be already risky? My ISA estimate table Do you think it could work with this change as 160mm CSA system?I would regard that space behind the firebox rather cramped, 10 cm would be sufficient I would say. And yes, 5.6 m² would be adequate. **************************************************************************************************************** Thanks again for very useful information Peter. I will work it out to have that 10 cm behind the firebox and oven for free ISA and gas movement. I also just found that most of the old contraflow structure cards I got, seem to have always the vertical smoke channels minimum of 70-80 mm wide, although of course the bell structure and operation is bit different. I just demolished the old fireplace yesterday. It ended up to be a tough small cubicle as the creators had been using very much of iron strengthened concrete Later this week I'll open the surrounding floor to inspect the foundations. On the ground there will be a car sized area laid full with large granite boulders with masonry surface on top of them (checked under the house), but between that and the floor I don't know yet. If needed, I am planning to cast an iron strengthened slab of 10 cm on top of the old slab which is only of the previous installation size (90cmx60cm), anchoring this top slab directly to granite with concrete pillars and installing bitum cloth pieces in between for capillary humidity insulation. In that case I will be also able to expand the footprint of my BR to be less cramped and also ensure that foundation is secure enough. I will also then have an extra margin for potential skin masonry later on. Ordering materials tonight regards, -Antti-
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Post by rakettimuurari on Sept 1, 2017 10:38:40 GMT -8
Evening Peter and thank you for your answer! About slim walls: as you are able to see in Yasin's designs the firebrick walls are on edge. But that isn't the whole story, most heaters like that are built with an outside skin of brick or unfired mud bricks, even concrete street paving could be used. So the whole of the structure is much more solid and stable than you would expect at first sight. Those double skinned bells are slower in emitting heat than their single skin relatives. So there's more mass in there and the outer skin won't crack as easily due to heat expansion, as long as the outer skin is kept separate from the inner skin. I am led to believe Rockwool sheets of 10 mm thick are available in Finland, those are ideal for separation purposes and the insulation value is very minor when the temperatures are taken into consideration.
You are right about the skin thing. Most of the contraflows here today get the second layer; it is also very easy to surface-finish as cover does not expand so much. Most of the masons use 10mm wool in between as it gives automatically good separation joint and more freedom in bricklaying. I will be using same stuff for expansion joints too. Back in the days they used normal cardboard and best ones went by the eye estimate. Double layer was my original plan too... until i started to count the mass. With covering layer - even from the lightest bricks - the mass passed 2000kg (the walls and firebox by single skin will still have some 1600kg +; oven not counted in that!). I want to have both - delayed heat transfer as well as powered one; so i thought i will go first with single skin but if room temperature is too high after a batch burned, I have been considering about adding the cover masonry afterwards. I am after clearly warm surface but also at least 12h storage, but I dont have math to count it so I thought to experiment. Single layer system (12,4cm) should have the highest surface warmth some 5,5 hrs after lighting the fire and cool down is probably affected by the mass? Some Finnish mason wrote that it would be better to have cover masonry thinner than the body masonry itself? What are your thoughts on that? All in all I feel its better to make it too hot/light first than too cold and heavy. Your intention seems to keep the heater small, why are you planning to build a 160 mm model then? Maybe because that's the chimney size?
Yes; Chimney size has been the main reason and also habits. Somehow the firebox in 160mm BR still feels so small compared my current one so it was hard to think to have even smaller one... I was after max potential. You have made to rethink this however. I should not be too worried about the footprint though as I am quite sure the original heater has been really much larger.
What would you think about this:
I could try to expand the area of the heater depth wise by adding maybe 10cm more depth to whole footprint. This way i could free the back wall ISA completely, the firebox and oven being entirely separate from it (not attached to it as in original plan). Do you think that only some 3 to 5 cm gap behind the firebox and oven would enable the free flow for gases? With this maneuver I quickly counted total ISA estimate would be around 5.6m2. Down-scaling system to 6" could be already risky? My ISA estimate table
Do you think it could work with this change as 160mm CSA system?
Cheers,
-Antti-
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Post by rakettimuurari on Sept 1, 2017 1:54:04 GMT -8
Hello dylan, I see your post was already a while ago; did u finish your plan? Its really cool to find a brewer around rockets Maybe we could exchange some ideas? I've been home-brewing three years now and using the wood operated water boiler of my sauna. I've been figuring out improved system but I still get around fine with my ad hoc one. Water boiler is 80l large -> I fill 45l of water -> 25l steel pot with malts inside is inserted into the boiler. Then the boiler is heated gradually increasing heat and adding fuel (and water to malts and mixing the malts) every 30 min for 5-7 hrs and raising the temp of the malts from 30c to 80c gradually; during which the malt releases the sugars. Water in between lets me to be away from the boiler 30 min at times because malts wont burn in the steel bottom... Example of the boiler: www.puuilo.fi/epages/puuilo.sf/fi_FI/?ObjectPath=/Shops/2014011303/Products/10028914These are essentially metal drums, inner surface coated with light but solid insulative refractory. Chimney opening is up very near the upper edge. Pot with sleeves on its top edges is inserted to a tightly fitted opening and supported by its sleeves thus closing the top cavity between the pot and the refractory coated metal drum. There is a normal stove fireplace in bottom and the bottom of the water pot is essentially roof of the fireplace enabling direct heat conduction. What comes to your design - it is very interesting! If u dont mind I could suggest something. I would try to make the riser exit cavity under your beer bowl so that it would force the gases to flow along the opposite side of the pot relative to chimney opening first. Then turn towards the chimney opening at chimney hole level. This way it could be easier to make sure that u get the riser exit gap large enough. Also would like to divide the stream horizontally in the dead middle of the stream to guide it on both sides of pot before exit... Could this spread the heat bit more. drive.google.com/open?id=0B_O6G3ixIMfHSVd6R2cyeWoxcncI also once saw a picture about old Finnish water boiler where the smoke channel spiraled up along the huge water boiler pot before exiting to chimney; I wonder if upwards spiraling heat riser was ever tried? About the bell option... how about like this; u can heat the brewery too and beer is not burning into the pot...? drive.google.com/open?id=0B_O6G3ixIMfHQml4ZERMVjh4eVEU would need stairs though... Let me know how have u ended up with brewer! Cheers, -Antti-
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Post by rakettimuurari on Aug 31, 2017 0:47:40 GMT -8
Thank you Peter for welcoming and also for your observations! I enclose some drawings for better illustration (those with the work label "batch devil" --> long story..) drive.google.com/drive/folders/0B_O6G3ixIMfHdm1sN3R1VEdpbTA?usp=sharing(seems to work only by "open in new tab" - option) "The bell looks quite cramped, what's the projected thickness of the walls?"This is making also me feel bit uneasy; not to mention that old chimney itself is part of the whole area. In my estimates I have no chance to get even close to 5 m2 ISA but I was hoping that quite massive oven structure with its surfaces plus the supporting column would amend some of the missing wall surface. I was planning to lay bricks flat (124mm wall thickness) in front and sides with back wall being bricks on sides (57mm). My wish would be to delay the heat transfer more and have more solid structure. Somehow I felt uneasy about thinking that the walls would be only 57mm thick and height of a man. I was planning to make sure that gasses and air have movement routes on top, both sides and also below the firebox. But cramped it will be; it looks more like a contraflow designed in intoxicated state than a bell truth to be said. How about removing the back wall of the heater and anchoring the sides directly to the original brick firewall behind the heater? The wall is in the middle of the house (built in 30's) and has stone slabs as decorative surface. It had originally relatively big contraflow baking oven standing against it. Oven was then replaced with small open fireplace at 70's 4 owners ago and the closed Harvia fireplace insert was added some 30 years later which was two owners ago. Behind the wall in kitchen there is an opening for another chimney. I am quite sure there have originally been a wood-stove inserted. drive.google.com/open?id=0B_O6G3ixIMfHOFo5Wi1fZ0JaMW8(seems to work only by "open in new tab" - option) "Essentially, by inserting an oven like that you are building an untested construction. Maybe you need to look at the designs of Yasin Gach of France. His sidewinder 6700 W do sport a working black oven and is a very lean build.uzume-asso.org/batchrocket_plans.html"
Yes; that is true but I kind of like to research this kind possibility with oven. I will probably prepare a replaceable module with which I can practically just extend the riser through the oven ceiling if a need arises. I wont hard seal the roof of the whole heater before i know The oven would practically has 160mm hole in the bottom back left corner and then an oven wide slit with system CSA? or more? on the roof of the oven closer to the front and the door. I checked Yasin's plan. I looks interesting and lean yes - I will still need to put it in pieces and give closer inspection; I am just somehow reluctant towards slim walls... "Your remark about "just normal batch rocket & bell operation" made me smile, keep in mind development started back in 2012, much more recent than the contraflow concept which is well-known in Finland." Now you made me smile You are very right in that. It is just my biased trajectory as I have read so much more about RMH's and BR's than our old contraflows. It is getting balanced; I got handful of old contraflow plans and guidebooks just recently and been reading them for a month now. "You have to go far to see what was close to you".. or how to they say? In short, with my planned construction I am hoping to avoid building more complicated secondary burn chamber (replaced by the batch rocket) and carefully measured and lined smoke channels (replaced by the bell operation). "Personally, I don't like bypasses that much, in particular when situated in the top of the bell. When you want one, please place it one third of the bell height down to avoid the highest temperatures."
"As of today, I am opposed to make the port deeper and narrower, this is a leap away from the tested and proved design. You are on your own when trying to build a change design.What I would recommend in your case: whatever you do, you have to cut some bricks. Cut the bricks left and right of the port under 45 degrees at the back, so they'll fit nicely to the riser and use a proper high-temp refractory cement to fix it together. This way, the port could be less deep like, say, 60 mm. An often used alternatively method is to cut up the riser left and right of the port so there's a flat surface to place against the firebox bricks."I gladly take heed of your advice about the bypass. Same goes with the port depth - thanks! It also dawned to me suddenly that it would be no problem to cut the bricks as I will be deeply immersed in brick cutting business anyways. My sincere thanks for your observations, -Antti-
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Post by rakettimuurari on Aug 30, 2017 0:09:49 GMT -8
Hi Satamax! You seem to have an over-watch everywhere
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Post by rakettimuurari on Aug 28, 2017 8:06:19 GMT -8
Hello forum! My name is (mr) Antti Säippä; I am from Lempäälä, Finland. I have been following the forum one year now and found it as I was building standard RMH in my sauna's dressing room (https://permies.com/t/60768/RMH-sauna-cabin-success#516820) utilizing permies.com. I have a problem... I feel I am getting knee deep or more into rockets ... and after this maybe neck deep.
But still - I want to express my thanks for all this freely and enthusiastically shared information and especially the pioneering work and heavy duty rinse-and-repeat-field testing made by Peter and the others! You really have smoothed out the entry level for all this.... Batch rocket / brick sidewinder with cast riser / fire burning through a baking oven in to the single brick bellHave been planning a batch rocket for my living room a year now. My challenge is to fit 160mm system to a relatively small space and with baking oven. At the moment I am sketching it up. It will replace a small, maybe 400kg old open fireplace which has closed fireplace module installed. PLAN in SHORT:Dimensions of the heater: width: 135cm depth: 60cm height: 185cm
Firebox will be placed on the right third when faced from front. Sidewinder design will open to the left from firebox (-still if faced from front-) placing the riser in the middle of the width of the heater.
Riser top will be connected directly to the bottom of a compact and vaulted baking oven (w: 41cm, h: 23cm, d:53cm), essentially the oven thus having a 160mm opening inside in the floor, just adjacent to the back wall of the oven. From there the burning gases would travel along the oven vaulted ceiling towards the baking oven door some 30cm, finally entering through the smoke channel in the vaulted ceiling some 10cm before the baking oven door. After the oven the gases are able to freely rise to the top of the bell... Rest is just normal batch rocket & bell operation. Behind the whole installation (basically separated by fire insulating wool, stands old firewall with 6m high brick chimney with excellent draft.
I will install also a direct flow summer damper on topside of the bell for summer baking and for lighting the thing . Theoretically the baking oven could also be operated directly by burning the wood in it but i don't really see point in it as burning will be more unclean...
I got the idea of the oven construction one night but then bit later- like always - realized that i was not the first one... kind of: mainewoodheat.com/masonry-heaters/the-albiecore/
I would appreciate any thoughts about the planned construction. Is there any deadly flaw related to operating principles? I would also like to pose one more exact question too. How much can the depth of the port be varied from given dimensions?
Originally i was settling with 57mm which is the standard width of the Finnish fire brick on its side... However after a successful mold experiment with castable refractory I am going for a 35mm thick cast riser core surrounded by perlite filled brick box (latter also partly supporting the oven). However, because of the vertical mold the riser will be round and uniform all the way with its 3,5cm thickness. This again poses a problem because i'd like to have the firebox walls made by bricks laying on their side (that 57mm) for strength and solidity. This would result in port depth of 35mm (riser wall) + 57mm (firebox side wall) =92mm. Peter wrote somewhere earlier that thing get worse especially after exceeding 100mm if I got it right... Any thoughts? Or should i narrow the port to compensate the added depth to maintain smooth operation and stream properties? I don't think I have proper means to swipe and shape the ready cast riser core to fit it closer to firebox thus shortening the depth of the port, and yet getting it to be even and smooth enough to seamlessly attach to port opening on firebox wall. could any of u to figure a solution for this? Thanks for your sharing and help! -Antti- **It has begun - i ordered the firebox door**
www.talotarvike.com/svt-takkaluukku-410-kaasutiivis-325x290mm-oikeakatinen-p40913
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