dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 13, 2017 13:55:12 GMT -8
Hello, People.. I am on to the new project now. This project will be done and it will start to be built on 1st of June, 2017. I have a batchbox rocket stove in mind (and on paper, and on SketchUp): CORE:system size 180mm sidewinder brick core octagonal heat riser floor channel SYSTEM:it is a single bell system which includes a bench and a metal white oven. START OF BUILDING:1. june, 2017 OTHER INFO:The bell will be built like double skin with schamotte bricks inside where the temperature is the highest (that is main, upper part of the bell) and regular old handmade red bricks for the outer skin. The bench will be built only with outer layer of handmade red bricks. The top of the bench will be concrete block (because i do not expect temperature higher than 250°C there). Everything will be plastered at the end. Some or all parts of the plaster will be strengthened with borax/casein mix... MAIN IDEAS FOR DESIGN ARE FROM:1. from my previous built that heats me nicely from 2013 onwards: mmmm, a toasty bench :-) (http://donkey32.proboards.com/thread/691?page=15) 2. Peter's build of 8" BRMH at MHA meeting - single+double skin combo (http://batchrocket.eu/en/applications#culdesac) 3. Nice description of sidewinder brick core with floor channel (http://batchrocket.eu/en/designs#core6) WHERE TO BE BUILTOn the concrete floor with tiles - the floor is made to hold more than enough weight. The back of the stove will be put directly to the masonry wall. Here is the photo of actual place. The bricked floor is 180cm x 118cm. The existing flue is insulated 20cm diameter pipe, over 6 meters high from the connection on the wall. The connection is 205cm high from the floor... (Sketchup file follows...) .jpg) EXPECTED END RESULTSomewhere among this sketch:  |
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 13, 2017 13:55:38 GMT -8
---Saved post for the end result---
|
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 13, 2017 14:54:37 GMT -8
The outer appearance is a wish of future owners, so there is not much to be done here, but if someone has a better design, speak up... The owner doesn't want it to be square, because of personal preferences... Now, here are questions, doubts things that i am not sure...1. This heater will be built for a friend and i would really like to do my best to make it great... Right now i have a fast SketchUp file. There can be seen dimensions for this stove, and based on my math, the ISA of 180mm system diameter should be about 7,60 m 2. With my calculation i came to 7,50 m 2, which i would say is OK. From my previous experience i prefer to make ISA smaller and if the stack temperature is too hot, i can put some more bricks inside the bell through the cleaning doors. Do you find calculated ISA to be OK?2. Inside the bell there is a brick "flue" leading from the bottom of the bell to the top and out to the chimney connection. I think that exhaust at the bottom of it is enough to not cause constrictions to the gases. Does it look okay?3. In the middle of it there is a bypass opening in the mentioned brick "flue". I am thinking of even lowering it to 75cm height from the bottom. I think that this should be enough to prevent possible troubles when cold starting the stove in a not so cold weather - if it would be needed at all... Does it look okay? Would you put it somewhere else4. I put two cleaning ports into the stove. Those are seen on the left of the heater. One on the bench and one on the outside of the vertical flue that leads to the chimney. Apart from those two, the metal oven can be removed quite easily and i can inspect/clean the heater from there... Are positions okay? Would you put them somewhere else?5. You see the core with a riser... (do not bother with a port at the end of the firebox - i will fix it in near future... It WILL be a right sidewinder version... But speaking of heat riser... what would you choose for a material: -3cm thick shamotte brick, with vermiculite board (600kg/cub. meter) around it. -3cm thick vermiculite board (1200kg/cub.meter) with another vermiculite board (600kg/cub meter) around it. -3cm thick shamotte brick with perlite-clay mix around it in some kind of metal compartment... I like 1200kg/cub.meter vermiculite board (1150°C rated, datasheed here) version but i am concerned regarding the highest temperatures and durability. Do you have any other option in the pocket?Also if you see a sketchup file, all around the riser there will be a perlite clay mix in a metal compartment (it will touch the back and part of the right wall of the bell). In this way saved more ISA for the bench and for the oven... 6. Metal oven... Do you think that the oven position is too high/ to low/ just about right in height? The photo of the oven is below, it will be revitalised with INOX prior to putting it in.  7. And for the last thing in this post - i have another burning question so that i can make a reliable firebox... It is about misterious brick moving at high temperatures...This one is posted here . SketchUp file is available here. It is not polished yet, floor channel comes on the right, door will be present, etc... And please, when you open it, click Edit>Unhide>All to see everything that is to be seen :-) I hope that i will be able to make a decently organised thread. I really hope to make another magnificent heater to be in service for many happy years to come, too. And last but not least, i hope that you will help me with your expertise as you did last time, back in the 2013 :-) I very look forward to your reply, Klemen from Slovenia! |
|
|
|
Post by peterberg on May 14, 2017 2:50:22 GMT -8
Klemen, all your images aren't visible to me. Could you please look into that?
Even your avatar is absent...
|
|
|
|
Post by peterberg on May 14, 2017 12:37:16 GMT -8
1. This heater will be built for a friend and i would really like to do my best to make it great... Right now i have a fast SketchUp file. There can be seen dimensions for this stove, and based on my math, the ISA of 180mm system diameter should be about 7,60 m 2. With my calculation i came to 7,50 m 2, which i would say is OK. From my previous experience i prefer to make ISA smaller and if the stack temperature is too hot, i can put some more bricks inside the bell through the cleaning doors. Do you find calculated ISA to be OK?I didn't repeat the calculations but 7.5 m² should be fine, especially because you also planned a bypass. Adding another m² wouldn't pose a problem under these circumstances I'd think. My recommended ISA figures are on the conservative side, remember? 2. Inside the bell there is a brick "flue" leading from the bottom of the bell to the top and out to the chimney connection. I think that exhaust at the bottom of it is enough to not cause constrictions to the gases. Does it look okay?It looks OK although I am inclined to make the openings lower and on three sides. This way more heat can be retained in the bench. 3. In the middle of it there is a bypass opening in the mentioned brick "flue". I am thinking of even lowering it to 75cm height from the bottom. I think that this should be enough to prevent possible troubles when cold starting the stove in a not so cold weather - if it would be needed at all... Does it look okay? Would you put it somewhere elseHalfway should be fine. 4. I put two cleaning ports into the stove. Those are seen on the left of the heater. One on the bench and one on the outside of the vertical flue that leads to the chimney. Apart from those two, the metal oven can be removed quite easily and i can inspect/clean the heater from there... Are positions okay? Would you put them somewhere else?As long as you are able to reach a large part of the bell's floor this is OK. 5. You see the core with a riser... (do not bother with a port at the end of the firebox - i will fix it in near future... It WILL be a right sidewinder version... But speaking of heat riser... what would you choose for a material: -3cm thick shamotte brick, with vermiculite board (600kg/cub. meter) around it. -3cm thick vermiculite board (1200kg/cub.meter) with another vermiculite board (600kg/cub meter) around it. -3cm thick shamotte brick with perlite-clay mix around it in some kind of metal compartment... I like 1200kg/cub.meter vermiculite board (1150°C rated, datasheed here) version but i am concerned regarding the highest temperatures and durability. Do you have any other option in the pocket?Out of 30 mm chamotte and wrapped with superwool, chickenwire mesh around it is another possibility. 6. Metal oven... Do you think that the oven position is too high/ to low/ just about right in height? The photo of the oven is below, it will be revitalised with INOX prior to putting it in.  Not much experience with ovens, sorry. 7. And for the last thing in this post - i have another burning question so that i can make a reliable firebox... It is about misterious brick moving at high temperatures...This one is posted here . This is a tricky question. All the bricks are expanding while getting hot, nothing new. Shrinking would be fairly even at both ends of each when the pressure of other bricks on top is very well distributed. When one end of a brick is recieving more pressure from above than the other end it will eventually wander to the side where it is fixed best. Some people build steel frames around the firebox in order to keep things in place. |
|
|
|
Post by Jura on May 15, 2017 0:14:12 GMT -8
I also experiencing the issue with your images visibility.
|
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 15, 2017 0:31:44 GMT -8
Klemen, all your images aren't visible to me. Could you please look into that? Even your avatar is absent... Hi, Peter. Now they should be visible... Thanks! |
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 15, 2017 1:06:46 GMT -8
I didn't repeat the calculations but 7.5 m² should be fine, especially because you also planned a bypass. Adding another m² wouldn't pose a problem under these circumstances I'd think. My recommended ISA figures are on the conservative side, remember? Hi, Peter. Yes, i do remember the safe side ISA figures that you recommend... I will think about that additional m². It looks OK although I am inclined to make the openings lower and on three sides. This way more heat can be retained in the bench. Hm, i was also thinking about that possibility. Nice. i will give it a thought. Making a slope in bricks that lead to the flue so that the path is more smooth to the gasses will maybe even lower the restriction... Out of 30 mm chamotte and wrapped with superwool, chickenwire mesh around it is another possibility. If one would pick this possibility, would it be still wise to use clay slip to put these together? If i put perlite/clay mix around it, it would feel safer to me... I am leaning towards the vermiculite board (1200 density) because it is really simple to cut and construct and hold together. But i am concerned about longevity of vermiculite board compared to chamotte bricks. Should i be concerned about that or are both materials good enough for this task? I intend to put perlite-clay mix around the riser anyway.. If you see sketchup file and image below you can see a lot of white insulated volume around. But thinking of it now, maybe i will remove some of it on the RIGHT side of the heater's wall to get some more ISA (about 0,27m 2). This is a tricky question. All the bricks are expanding while getting hot, nothing new. Shrinking would be fairly even at both ends of each when the pressure of other bricks on top is very well distributed. When one end of a brick is recieving more pressure from above than the other end it will eventually wander to the side where it is fixed best. Some people build steel frames around the firebox in order to keep things in place. Wow, this is quite an interesting info... Building the steel frames around the firebox would keep the bricks from moving outside. But not towards the inside... I am inclined to make few holes in the top + bottom rows of chamotte and connect them with metal pins...These should prevent excessive movement, but still allow expansion when hot... Thanks for the replies. But i have still some more questions in a rows... |
|
|
|
Post by peterberg on May 15, 2017 1:49:48 GMT -8
Three centimeter of chamotte should be done with proper refractory cement or something like that when insulated with superwool. You need to make a canister of some sort to hold the perlite/clay mix but it's very effective. Maybe a piece of large diameter chimney pipe?
|
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 15, 2017 2:31:11 GMT -8
Three centimeter of chamotte should be done with proper refractory cement or something like that when insulated with superwool. You need to make a canister of some sort to hold the perlite/clay mix but it's very effective. Maybe a piece of large diameter chimney pipe? Since i have an oven insert above the firebox i must not use too thick insulation at that side. I will again calculate the ISA to be sure and then decide if canister will be cylindrical (consequentially more ISA) or 5- cornered. If the latter, i will make it from sheet metal connected with some L profiles... If i choose 3cm chamotte bricks for the riser i might make the whole firebox and riser with refractory cement... I will have to use it anyway... Using vermiculite board for the riser with perlite/clay surroundings would make the core super fast to heat up... I am still inclined to use vermiculite boards... But would they hold in there for, say at least 15, 20 years? There will be no abrasion, but regular heating/cooling cycles... Question no. 8.: Above the bell there is a large chamote brick for closure. Dimensions are 7cm x 60 x 90cm. I will cut it down, but there is quite an expansion to reach... The flames will burst directly into it... Will it hold well? Does anyone have concerns about that? It wont be glued to the sides - i will just lay it down to the chamotte walls on some cheramic blanket... Question no. 9.: The thin cheramic blanket layer will also be present between inner (chamotte) and outer (red brick) layer to prevent cracking... But i am not sure how to build details around the vertical flue coming from the inside to the outside of the heater. Also i am not sure how to cover the whole thing over the large chamotte bricks (inner ceiling)... I would really like to do my best to prevent cracking when finishing layer comes over... Any suggestions are highly welcomed... |
|
|
|
Post by peterberg on May 15, 2017 4:05:16 GMT -8
Using vermiculite board for the riser with perlite/clay surroundings would make the core super fast to heat up... I am still inclined to use vermiculite boards... But would they hold in there for, say at least 15, 20 years? There will be no abrasion, but regular heating/cooling cycles... Vermiculite board in the lower part of the riser won't hold for 20 years, I'm afraid. You mentioned it is specced for a maximum temperature of 1150º C. Temperature in that part would be 1200º C and more regularly. If you ask me, I would use split chamotte bricks (30 mm) and an adequate insulation material which could be that board, by the way. Question no. 8.: Above the bell there is a large chamote brick for closure. Dimensions are 7cm x 60 x 90cm. I will cut it down, but there is quite an expansion to reach... The flames will burst directly into it... Will it hold well? Does anyone have concerns about that? It wont be glued to the sides - i will just lay it down to the chamotte walls on some cheramic blanket... It will hold probably quite well, but these heating cooling cycles could cause creep again. You could use a simple steel wire to hold those slabs together. Question no. 9.: The thin cheramic blanket layer will also be present between inner (chamotte) and outer (red brick) layer to prevent cracking... But i am not sure how to build details around the vertical flue coming from the inside to the outside of the heater. Also i am not sure how to cover the whole thing over the large chamotte bricks (inner ceiling)... I would really like to do my best to prevent cracking when finishing layer comes over... Any suggestions are highly welcomed... Hmmm... May I suggest you build the inner shell complete all around and the internal flue as just two extra walls in the corner? This way you could just cut out a corner out of the top slab and close the square hole with bricks. I'll copy a part of your drawing with this details filled in later today. |
|
|
|
Post by peterberg on May 15, 2017 5:20:53 GMT -8
OK, details are filled in. See the sketchup file.The internal chimney is like I proposed, there are three openings down at floor level, only 120 mm high. This is still waaay larger together than needed, 200% of system csa would be fine. The height of the exhaust openings is now as small as 120 mm. The top end shows how I would do it. Assuming another layer would come on top of the refractory slabs the chimney connection could be done with an elbow and a metal plate with a hole in it, mounted between the layers and sealed with keramic blanket. If there's a habitated room behind the back wall of the heater I would leave the outer skin away there and place the inner shell directly against that wall. A thicker layer of keramic blanket would be sufficient to spread the heat, so the wall in the other room would be quite warm as well. Years ago I built a high mass heater for a friend against a double brick wall, with 50 mm of rockwool to insulate it from the heater. The kitchen is on the other side and that particular wall is warm the entire winter, despite the rockwool. We built the heater up to the ceiling with 150 mm of rockwool and two cast slabs to cover it. Above the heater is a concrete floor of 150 mm and a bedroom. The owner is able to find the location of the heater in winter with his eyes closed and walking on bare feet. |
|
|
|
Post by satamax on May 15, 2017 5:45:06 GMT -8
Dvawolk, refering to your ketchup drawing, may be extend your hearth/slab or tiling a bit more in front of the firebox. Just in case!
|
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 16, 2017 3:57:06 GMT -8
Vermiculite board in the lower part of the riser won't hold for 20 years, I'm afraid. You mentioned it is specced for a maximum temperature of 1150º C. Temperature in that part would be 1200º C and more regularly. If you ask me, I would use split chamotte bricks (30 mm) and an adequate insulation material which could be that board, by the way. Ok. Then i would go for split chamotte bricks for the inside of the heat riser. I can then surround them with the lighter vermiculite board (rated only 1100°C, but more insulative) or perlite/clay mix. If i use vermiculite board, i would be less hassle... But then i will get a larger ISA because the insulation would not reach to the bell's walls. I will calculate ISA again. It will hold probably quite well, but these heating cooling cycles could cause creep again. You could use a simple steel wire to hold those slabs together. Ok. I think i understand. I will put a steel wire around the circumference of both slabs together so that they will stay in place... The internal chimney is like I proposed, there are three openings down at floor level, only 120 mm high. This is still waaay larger together than needed, 200% of system csa would be fine. The height of the exhaust openings is now as small as 120 mm. Nice. This will take really only the lowest parts of the gasses! I will implement that... The top end shows how I would do it. Assuming another layer would come on top of the refractory slabs the chimney connection could be done with an elbow and a metal plate with a hole in it, mounted between the layers and sealed with ceramic blanket. Yes, over the refractory slabs, another layer will be layed... But i am not sure how/what should i put over it.. I would really like to make it crack'proof (or at least lower the cracking possibility to a reasonable degree) One option is to heighten the outer (red brick walls) slightly over the refractory slabs and then put on a concrete layer... Since below it there will be a 7cm thick refractory material, this could also be rebarred i would say... Or maybe i could even make this layer right on its place. If i make it with dry enough concrete mix it would be okay to put it directly on the ceramic blanket with heavy duty aluminium foil on top? Or not? Rebars, yes or no? Its thickness? It would be easiest just to have the refractory slabs and then to put a thick clay plaster - but this will be prone to cracking... Still i am surprised that the plaster on the heater that you, Peter, built at MHA didn't got any cracks... There has been only one layer of slabs above, right? The chimney inlet is 200mm diameter at 45°. It will be reduced to 180mm and then a 135° elbow to the heater. If there's a habitated room behind the back wall of the heater I would leave the outer skin away there and place the inner shell directly against that wall. A thicker layer of keramic blanket would be sufficient to spread the heat, so the wall in the other room would be quite warm as well. I was thinking about that, but the room behind is not really habitated. It is a part of the house (not an outside wall), i am sure that it will get slightly warm (it is a similar thing at my place ), but i would prefer that the main heat is released to actual room. Dvawolk, refering to your ketchup drawing, may be extend your hearth/slab or tiling a bit more in front of the firebox. Just in case! Hi, Satamax. We were thinking about that, but i guess it will stay the way it is...Even the radiation through the window will heat the floor... But when handling the firebox full of coals caution will be needed... If the slab would be done with this kind of heater in mind, it would be safer to be abit larger... |
|
dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
|
Post by dvawolk on May 16, 2017 4:25:38 GMT -8
Question no. 10:I was just trying to calculate the dimensions of the floor channel for 180mm system... All info is well presented at batchrocket.eu, except the height of vertical part of floor channel... I don't recall it being explained anywhere... By feel i would say that it is in some proportion to the port height? I did a detailed sketch of the firebox door frame and the door... they will be made of stainless steel, T (30x30x4 mm) and U (80x40x4mm) profiles used for the main part. The majority of the design for the doors is "stealed" from here. I also have an old ceramic glass at hand that will come really handy :-)  The blue line shows where the 8mm sealing cheramic will be present. The U profile rectangle will sit on the red brick layer.  In the next image there are two metal rectangles market with red. They are movable from the inside. Once the stove will be fine tuned, they will be fixed in place. I prefer to have slightly too large inlet at first, just in case... Or do you think this is an overkill? The primary air intake is tilting to open... I am concerned because the floor channel tube is not in the middle but on the right... I think that it will be better to put the primary air opening to the right so that the floor channel gets the air with least restriction... Would you agree or it doesn't matter significantly...  Any doubts/recommendations regarding the door are highly welcome.Thanks again for all the replies, Klemen
|
|
