question about my rocket batch 150

[cedro]

Hello everybody



after reading many trheads and experimenting with scketchup here is finally my project:

Combustion chamber in refractory bricks

6.1" x 6.1" firebrick square riser



P-channel on the floor



bell interior dimensions: 17" x 50" x 55"

bell stratification: first layer in concrete blocks, second layer in bricks, third layer in double refractory bricks with 1/2" ceramic fiber

Ceiling: 2 layers of fire bricks divided by 1/2" of ceramic fiber with a layer of refractory cement on top

For the first two layers i use portland cement for the last one I use refractory cement



gases exit into a cube of bricks and then into a 150 mm pipe



between the wall and the bell using 3" cellular concrete



to insulate the wooden floor I use a layer of cement and clay pebbles and a layer of bricks and tiles on top



glass cooking plate



1" iron plate on bell for radiant heat



in the drawings I forgot to draw the wood floor oops...



my questions:



1) Is a riser with 2" thick firebricks with 1" ceramic fiber are efficient?



2) between the bricks of the third layer of the bell is 1" of ceramic fiber enough?



3) is the gas outlet from the hood correct?





what do you think? thanks to whoever can answer me


the photo in my google drive: drive.google.com/drive/folders/1Of0xqAWaw2_Hk76ZuUgyCYIybsGKxa7k?usp=sharing

[cedro]

weila, I made new changes to my project:

riser with 1" fire brick

ceramic fiber insulator between the combustion chamber and the bell

I removed the iron plate on the side of the bell

I added a 2" cast iron plaque to the ceiling of the bell



what do you think of my gas output? Could the 15" long flat piece and two 90 degree bends be a problem?

the photo of the project: drive.google.com/drive/folders/1SM9dmkT5IleW3kGpWuZ5t1OTbFhoi2an?usp=sharing

[peterberg]

As I see it, the space between bricks and wood floor wouldn't work as well. There are channels under the bell and the firebox. In order to make this effective, these channels should also be along the wall where the channels along the floor lead into. The net effect would be an air current under the bell and along the wall, keeping the floor and wall cool.

It escapes me what you want with the hot cast iron plate on top of the bell. You won't need this when the heater is ran every day with at least one batch. In case the thing is started cold quite often, sit in front of it while it burns. The radiation from the door and the cooking plate on top of the firebox will throw quite some heat into the room.

When closing the bell with steel T-bars and bricks, try to avoid steel directly above the riser.

The riser need to be insulated with 1" of superwool. Between the 1st and 2nd layer of the bell's top one inch of superwool is sufficient. The bricks on top will get warm just the same, you could add one more layer of bricks and again superwool in between.

The exhaust box is correct, the stove pipe to the chimney isn't, really. Swap one 90 degree elbow for a 45 degree one, that will reduce the friction somewhat.

Are you sure the bell is large enough? You could choose to shift the firebox up about 20", easier for your back and the cooking plate is at a better level. The wood floor wouldn't be heated up as much also.

The vertical stub of the floor channel seems to be on the short side. The air should be delivered at the top half of the port, so the snake's head should be above the middle.

[cedro]

Thanks for your help



I modified the project further

drive.google.com/drive/folders/1JoDkUTGSo-9hWCrm6DztSFhuAV_YfheE?usp=sharing



I continued the floor channels on the right wall. a layer of shoreline bricks and a layer of 3" cellular concrete panels. is this correct?

the other wall and insulating with 3" cellular concrete

I would like to insulate the walls as they are 2' thick stone


i had put the cast iron plate on top of the riser for some radiant heat and as an extra warm floor



if I make the top with 3 layers of bricks will this count in the ISA calculation?



I changed a 90 bend with a 45 bend even if the design is bad...



inside the wall is an asbestos rod 6" x 6" section 9' high



I raised the hearth off the ground, reduced the inner section of the bell and raised it. inside bell measures: 5.4' x 19" x 39"



are the measurements of the floor channel correct now?



the combustion chamber should be insulated?



Thanks for the help, I'm learning a lot

[cedro]

for the first layer I use concrete bricks with non-standard sizes like the ones in the photo

dimension: 9,4"x 4,7"x 2,7"


I split the refractory bricks in two to make the riser as in the photo



drive.google.com/drive/folders/119rF16Sj1YO8-N9K3TKgRIRuRYLe_5XE?usp=sharing

[peterberg]

Jan 8, 2023 13:52:03 GMT -8 cedro said:

I continued the floor channels on the right wall. a layer of shoreline bricks and a layer of 3" cellular concrete panels. is this correct?

Not entirely. It would be better to have the cellular concrete against the wall and a steel corrugated plate on spacers against the concrete. The steel plate will heat up by the radiation and an air current starts behind it. This way, the wall will remain cool and the radiation is converted to convection. Of course, you need to place the steel directly on the channels on the floor so the air current is running under the bell also.

Jan 8, 2023 13:52:03 GMT -8 cedro said:

the other wall and insulating with 3" cellular concrete
I would like to insulate the walls as they are 2' thick stone

I understand this is an internal wall. Maybe it would be nice to have some warmth at the other side. Also, this internal wall will act as an extension of the heater's mass, which is a good thing.
In case this wall is also and external one or you don't want heat there, place the same plate on spacers, 25 mm or 1" is already enough. This reflection shield doesn't connect to the channels under de bell so you can place it some space above it, let's say 100 mm. This way, the air current behind it is able to cool the metal.
I have this construction behind my heater, the plate is getting handwarm, that's all. Without it, the plasterboard wall surface became too hot to touch for more than a few seconds.

Jan 8, 2023 13:52:03 GMT -8 cedro said:

if I make the top with 3 layers of bricks will this count in the ISA calculation?

Yes, it does, as long as the inside of this bell top is primarily made of brick.

Jan 8, 2023 13:52:03 GMT -8 cedro said:

inside the wall is an asbestos rod 6" x 6" section 9' high

Not ideal, but it'll work for sure, as long as it ends above the highest point of the roof.

Jan 8, 2023 13:52:03 GMT -8 cedro said:

I raised the hearth off the ground, reduced the inner section of the bell and raised it. inside bell measures: 5.4' x 19" x 39"

Recalculated in metrics since you are located in Northern Italy, the combined walls/ceiling of the bell's ISA is 5.34 m². This also the recommended maximum for a 150 mm system. In order to avoid problems starting a cold and wet heater a bypass would be very, very handy.

Jan 8, 2023 13:52:03 GMT -8 cedro said:

are the measurements of the floor channel correct now?

Yes, they are.

Jan 8, 2023 13:52:03 GMT -8 cedro said:

the combustion chamber should be insulated?

Insulating the combustion chamber is optional, the riser however does require insulation over its full length.

[peterberg]

Jan 8, 2023 13:55:26 GMT -8 cedro said:

for the first layer I use concrete bricks with non-standard sizes like the ones in the photo. dimension: 9,4"x 4,7"x 2,7"

The concrete bricks are OK, what are you planning to use above the riser's level? The same bricks on its side would allow for split firebricks for the inside liner. Lots of dense mass, those concrete street clinkers.

I'd think you are on the right track, please keep going.

[cedro]

Thanks to these new tips I updated my project:  drive.google.com/drive/folders/1JhIeU_G_mMfSIFyDfVPUUgEtFxpsuY1v?usp=sharing

Not entirely. It would be better to have the cellular concrete against the wall and a steel corrugated plate on spacers against the concrete. The steel plate will heat up by the radiation and an air current starts behind it. This way, the wall will remain cool and the radiation is converted to convection. Of course, you need to place the steel directly on the channels on the floor so the air current is running under the bell also.

I understand this is an internal wall. Maybe it would be nice to have some warmth at the other side. Also, this internal wall will act as an extension of the heater's mass, which is a good thing.

In case this wall is also and external one or you don't want heat there, place the same plate on spacers, 25 mm or 1" is already enough. This reflection shield doesn't connect to the channels under de bell so you can place it some space above it, let's say 100 mm. This way, the air current behind it is able to cool the metal.

I have this construction behind my heater, the plate is getting handwarm, that's all. Without it, the plasterboard wall surface became too hot to touch for more than a few secondsaaa

the wall channels should be correct. their section is 120mm x 200mm/4,7"x7,8" , I don't understand if you also need the corrugated sheet to insert it under the bell? the corrugated sheet is thick 0,5 mm, 1/5"
Is the 100mm space under the rear sheet correct as in the image?

Yes, it does, as long as the inside of this bell top is primarily made of brick.

I was thinking of using sand filled hollow bricks for the second and third layers of the bell top

Recalculated in metrics since you are located in Northern Italy, the combined walls/ceiling of the bell's ISA is 5.34 m². This also the recommended maximum for a 150 mm system. In order to avoid problems starting a cold and wet heater a bypass would be very, very handy.

the by-pass is a 150 mm t-piece with a wood stove damper

The concrete bricks are OK, what are you planning to use above the riser's level? The same bricks on its side would allow for split firebricks for the inside liner. Lots of dense mass, those concrete street clinkers.



I'd think you are on the right track, please keep going.

clinkers street was left over from an old project.I don't have enough to build the all bell. 
for the outside of the third layer I was  using solid bricks as in the photo.

for the inner layer full firebrick or split firebricks. in between bricks 15mm/1" of ceramic fiber.
what do you think of my half brick surface?



i build a new pipe for exit bell: 
1)a vertical tube 1000mm/3,2' long
2)45° bend
3)piece of tube 100mm/4"
4) T tube
5) 90° bend
6) horizontal tube 150m/6"


I thought of inserting a thin 1mm sheet between the wooden floor and the concrete base.

I will reinforce the concrete with some iron inside. Is it possible to do it or does it cause expansion problems?


I attach a photo of the place where I will build the stove


Thanks again to anyone who can help me

[fiedia]

Cedro,

Why don't you share the skp file? It would be easier to have a closer look at many details.

Could you reduce the bell height? The bell top radiates a lot. It is more efficient at body's height than above your head.

The bell bottom will not be that warm (except for the firebox). I do not see any temperature problem below your stove since the firebox is sitting on two rows of brick and air gap.

Regarding steel reinforced concrete, I am still not sure if I figured well about the ground underneath your stove. What is it made of? Are the beams along or perpendicular to the bell longer side? Can you explain or make some drawing.   

[cedro]

hello fiedia

Here is the file of my project:  drive.google.com/drive/folders/1hYXPHz5NLkQDQQ8tPhG5XD8uC_Z3V6eG?usp=sharing

Could you reduce the bell height? The bell top radiates a lot. It is more efficient at body's height than above your head.

unfortunately the spaces do not allow me to make the bell lower, I could lower it by inserting the outlet tube inside the bell?

Regarding steel reinforced concrete, I am still not sure if I figured well about the ground underneath your stove. What is it made of? Are the beams along or perpendicular to the bell longer side? Can you explain or make some drawing.

I updated the project also drawing the existing floor and the reinforcement structure (different colors).

Above the wooden floor several layers in this order:
1) thin sheet of smooth steel
2) reinforced concrete base to distribute the weight
3) brick structure and tiles

[fiedia]

Thanks it is now much easier to see the details.

for the concrete steel bars, I would put them perpendicular to the wood beams. Then the bricks lying on the concrete perpendicular to the steel bars (if you are using steel bars, not steel mesh).

the part of the bell below the firebox bottom level will not get that warm. if you want, you can raise the bell floor by two bricks.

The heat riser is at 108 cm. It could be reduced to 86cm. You can lower the bell ceiling by 22cm.

Looks like you insulated the firebox. I did not and it's better so because it warms faster than the rest of the bell and radiates faster. I did put it along the side of the bell to optimize its heat radiation.

[josephcrawley]

I would advise against building on a wood floor. Even if the floor can hold it the weight will slowly deform the wood framing below.

Chopping a whole through the floor and laying up a block foundation is not that much work. It usually takes me and a partner 3 days to lay it and pour a slab on top. Laid dry with corners poured solid does the trick.

[cedro]

for the concrete steel bars, I would put them perpendicular to the wood beams. Then the bricks lying on the concrete perpendicular to the steel bars (if you are using steel bars, not steel mesh).

perfect, I was thinking of using 8mm iron rods

The heat riser is at 108 cm. It could be reduced to 86cm. You can lower the bell ceiling by 22cm.

reducing the height of the bell will also reduce the ISA, as I don't have room to widen the base

Looks like you insulated the firebox. I did not and it's better so because it warms faster than the rest of the bell and radiates faster. I did put it along the side of the bell to optimize its heat radiation.

thanks for the advice, I will not insulate the combustion chamber

[cedro]

I would advise against building on a wood floor. Even if the floor can hold it the weight will slowly deform the wood framing below.

Chopping a whole through the floor and laying up a block foundation is not that much work. It usually takes me and a partner 3 days to lay it and pour a slab on top. Laid dry with corners poured solid does the trick.

thanks for the answer josephcrawleyabout but unfortunately my wooden floor doesn't lay directly on the ground, I'm on the first floor, below me is the cellar

[josephcrawley]

Jan 14, 2023 14:43:54 GMT -8 cedro said:

thanks for the answer josephcrawleyabout but unfortunately my wooden floor doesn't lay directly on the ground, I'm on the first floor, below me is the cellar

No problems just lay the block foundation from the floor of the cellar up to the first floor and cap with your slab. Just did this with a cellar that was 8 feet below the floor level.