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Post by bigjuju4 on Sept 18, 2018 8:02:03 GMT -8
Hello community, I am new to the batchbox and would like to build an 200mm system with two bells, one inside the house and one outside. Connection of both will be done through a 300mm hole in the wall. A 200mm Pipe surrounded with 50mm ceramic fibre blanket insulation will go through that hole. The wall is a strawbale lime plastered wall. This is why I am using 50mm thick fibre blanket insulation. The back of both bells will be against the wall with a 50mm ceramic fibre blanket in between. I have built the box out of 50mm ceramic fibre boards. The box will be lined inside (bottom, left and right) with 25mm fire bricks and the internal dimensions of the box will match that of an 200mm system as specified by Peter. The heat riser will be octagonal and also built out of 50mm ceramic fibre boards. This will seat on 75mm of ceramic fibre board so as to be in line with the inside of the fire box. The bells will be built out of clay bricks, 230mmx115mmx75mm (from a dismantled chimney), not firebricks as they will not be in direct contact with the fire. Questions I have: - What can I use to cap the top of the inside barrel? I was thinking about using 6mm steel plate to have immediate heat release. - The bottom of the box will be 150mm from the floor seating on a steel frame. The top of the heat riser will be at 1665mm (150+50+25+1440). With the bell being 2200mm high, that will give me a 535mm clearance to the top of the steel plate. That way I hope to avoid having the steel plate exposed to too higher temperatures. Does that make sense or should I raise the bottom of the box by 235mm to have 300mm between the top of the heat riser and the steel plate cap? - What temperatures can I expect at the transition between the two bells and will the 50mm fibre blanket around the pipe connecting both bells and between the back wall of the bell and the house wall be enough not to affect the straw bale wall? The straw bale wall and the wall penetration have a 30mm lime plaster on top of it. - The floor is a concrete floor with ceramic tiles. Do I need to add an insulation layer on the floor or will the temperature be low enough as to not affect the tiles and the concrete below? - I will be adding a clean out opening at the bottom right back of the inside bell and bottom right of the structure supporting the chimney. Is that enough? Internal Dimensions Inside bell: width=970mm, height=2200mm, depth=590mm. ISA = 7.4sqm Outside bell: width=670mm, height=600mm, depth=370mm. ISA = 1.5sqm I have attached some pictures of the design with some measurements and I am looking for your feedback. All the dimensions on the images are external dimensions Pictures available here: drive.google.com/open?id=1TTte8ubv0mXUnUykzTdTiDUk3rx4VqcT
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Post by josephcrawley on Sept 25, 2018 15:36:00 GMT -8
You're going to have a rough time with cold starts without a bypass to get the draw moving. You could add one with a second higher hole in the wall to connect the big bell to the stove pipe. How much heat are you trying to get in the greenhouse? That short second bell probably won't put out to much heat considering the first bell will probably have an exit temp in the 150s F.
Regarding the plate you may want to weld some angle iron around the perimeter and an x through the center to keep the plate from warping and lifting off the top.
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Post by bigjuju4 on Sept 28, 2018 6:13:23 GMT -8
Thanks josephcrawley for the feedback, really appreciated. Instead of the second hole in the wall could I just use the clean out opening near the chimney bottom to get the draw started by burning a piece of paper there? The big bell is in the living room. The small bell is in an enclosed outside area. We could call it greenhouse as well ;-) I was looking to get enough heat so that we can seat outside comfortably in the winter. It does not get really cold here in the winter at night, lowest is around 6deg celcius outside at night. During the day around 14 deg celcius. But I guess because of the greenhouse effect and the massive outside lime plastered wall that is heated the day, we should get around 12deg celcius inside the greenhouse at night without heating. I am happy if we can get this up to 18 deg celcius with the second bell. The room is about 30sqm in total. I have uploaded videos of my first burn outside the house. I intend to run some more tests to make sure that the firebox and heat riser are all air tight. What should I look for to ensure that the whole system is properly working? I do not have all the tests instruments that Peter has. Will it be enough to measure how hot it gets at the top of the heat riser?
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Post by josephcrawley on Sept 28, 2018 10:53:20 GMT -8
From personnel experience it takes a good bit more than burning a piece of paper to get the draw going. Typically it takes about 15 minutes of running with the bypass open for my stove to draw properly. Before I installed the bypass I used the paper method and it sucked but not literally.
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dcp
New Member
Posts: 35
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Post by dcp on Aug 8, 2020 7:03:28 GMT -8
Feedback on placement of port related to riser is needed. I build with firebricks 230*110*64 mm a 200 mm riser for batch rocket. The internal diameter of riser is tangent to the backwall of box. Is this a good or a bad thing? How do I upload a picture here to show what I build allready
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fuegos
Full Member
not out of the woods yet
Posts: 177
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Post by fuegos on Aug 9, 2020 1:38:12 GMT -8
"How do I upload a picture here to show what I build allready" put them on google drive like the last photos .interesting build ,i'm looking forward to seeing the rest
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Post by Vortex on Aug 9, 2020 8:56:26 GMT -8
The forums picture hosting is full up, so you have to upload your pictures somewhere else and link to them from here. www.imgur.com/ seems to be the most popular and reliable site for free picture hosting that allows 3rd party linking at the moment.
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dcp
New Member
Posts: 35
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Post by dcp on Aug 9, 2020 12:01:40 GMT -8
Thanks Vortex. unfortunatelly the imgur app does not looks to good on feedbacks. A lottttt of adds.... I’m not so good on internet related things. just basic browsing.... but: as I search the forum I found that someone has the same ideea like mine. on Adventures with a horizontal feed topic page 23 Is Satamax on 31 jan 2013 on post 2,405. as reply docbb posted a draw sketchup showing satamax idea. Post 92 from 31 Jan 2013 cannot find anny answer/reaction related to that sketchup draw. My question is if does it matter if the port is tangent in riser. Not in the center of riser but tangent to the interior of riser. So the gases are forced to vortex in one direction . no double vortex by design Dan
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Post by peterberg on Aug 10, 2020 1:42:24 GMT -8
...as I search the forum I found that someone has the same ideea like mine. on Adventures with a horizontal feed topic page 23 Is Satamax on 31 jan 2013 on post 2,405. as reply docbb posted a draw sketchup showing satamax idea. Post 92 from 31 Jan 2013 cannot find anny answer/reaction related to that sketchup draw. My question is if does it matter if the port is tangent in riser. Not in the center of riser but tangent to the interior of riser. So the gases are forced to vortex in one direction . no double vortex by design Hi Dcp, I'd have a look at what you mean. Of course, first and foremost you are entitled to build what your fancy turn to. But don't expect this would yield the same results as the tried and tested designs. Rather the contrary, very early even before batchrocket development I tried a similar one like your idea. It didn't work as well, the clean period of the burn tended to be very short. And the whole of the core needed to be awfully hot coupled to a strong chimney draft before it would do that. The batchrocket on the other hand is optimized to run clean within minutes, even when cold. As it happens, on the batchrocket website there's a brand new article how the gas streams behave in this combustion core. Please see batchrocket.eu/en/workings#streamIn short: yes it does matter, the port does need that sharp corners left and right, the piece of wall above it plus the port should be centered to the riser. It's a very tight desin, all three of those details and more are necessary in order to obtain the results it promises on the tin.
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dcp
New Member
Posts: 35
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Post by dcp on Aug 10, 2020 2:58:24 GMT -8
Thanks a lot Peter. It happens that I do have connected to the same chimney a pellets oven that hold the house chimney hot. House chimney is 300 x 200 mm and 8 meters high. I do have a floor channel and the port is shorter than the firebox. I did build it following the dimensions from Batchrocket.eu I did have tested outside the house the core with port centerd on middle of the riser....worked great. Building the oven in house I had the feeling that it could be better if it spins only in one direction.... bad guess. Allso I saw on Youtube som images with the same idea: one single wortex So I did gone for it... I manage to upload my stove so here is what is build as for today imgshare.io/image/rbb-5.NZncecside view of port seen thru half build riser: imgshare.io/image/NZj0OgI will take it down and built it proper. another advice/clarification: square or octagonal inside of riser. I noticed that are both depicted on different places. does it matters?? thanks again
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Post by satamax on Aug 18, 2020 16:15:02 GMT -8
I didn't react, because i didn't pay attention. I think. I just looked at the drawing and your pics. And i'm afraid, that wouldn't generate a double vortex. The area on the left side of the port is just flush, and has no low pressure area for the incoming gases to whirlwind after the sharp orifice corners. Your design is what i call a cyclonic rocket. May be adding a "neutral vane" billpentz.com/woodworking/cyclone/cyclone_mods.php#CycloneFixes could produce a big single vortex. I have done something approaching, and melted the top of a gas canister. Thought, not enough pics to document. Give a bell to Martyn, he will be interested in this build.
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dcp
New Member
Posts: 35
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Post by dcp on Aug 20, 2020 2:52:12 GMT -8
Yes I think the cyclonic rocket is the appropriate name After reading the cyclone material I see that the «neutral vane» is ment to increase the speed thus increasing the inertia of small particles with the purpose of separation from air. As I undestand this speed will throw the particles to the outside, twards te wall of ciclone. The purpose of the «neutral valve» was to reduce the mix of new air with the air allready in the cyclone. I think that for a better burn of woodgases we need a good mix of fresh air with gases allready « in the ciclone» - riser in our case.
Maybe the incomplete burn is due to high speed in riser... on cyclone rocket
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Post by satamax on Aug 21, 2020 9:27:57 GMT -8
You understood well, but the mixing is enough even with a neutral vane. The good thing about it, is you increase velocity, so turbulence gets stronger afterwards. If the tube is not conical.
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dcp
New Member
Posts: 35
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Post by dcp on Aug 23, 2020 22:28:06 GMT -8
You understood well, but the mixing is enough even with a neutral vane. The good thing about it, is you increase velocity, so turbulence gets stronger afterwards. If the tube is not conical. Well.... if a neutral vane increase the air velocity and the turbulence is increased I have a question :does anybody has been tested the combination with the port tangent with innside of the riser and a short wall inside the riser twards the center? when I say short I mean in lenght tward center not in height. Height as same as the port With a wall innside riser we can get the edge that is mentioned by Peter and the speed shown by you satamax. just thinking.....
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Post by satamax on Aug 25, 2020 0:14:07 GMT -8
DCP, my understanding of the neutral vane, is, it stops the already rotating gases to crash into the incoming ones at an acute angle, instead, these follow the diameter of the cylinder, and surround that neutral vane, going pretty much the same direction. But the gases velocity at the neutral vane, and the surrounding gases is not the same.
Remember, this is purely theoretical.
And i think it can act as well as a sort of venturi accelerator.
Then, the gases going upwards in the cylinder face the boundary layer on the outside, slowing down creating turbulence between the layers. And the drag of the middle column, which is slower. The eye of the cyclone. Which in turn, create turbulence.
Just my understanding. If the gases in the cylinder were to crash directly into the incoming ones, that would create a big turbulence, but may be impede with the speed and further mixing.
That could be checked with plexiglass tubes and a smoke machine, for example.
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