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Post by DCish on Oct 27, 2017 6:35:20 GMT -8
Thanks for pointing me back here, Peter, not sure how I missed this thread and caught the other. You mention that the sooner flame enters the port, the better. I've also wondered if a large void on the other side of the port might be contributing to longer start-up times, requiring more energy to heat the entire space, and more flow to achieve turbulence. The next round of tinkering I'm planning is focused on trying to tailor that space to be as tight and well-insulated as possible to maximize heat retention and early production of turbulence, while still allowing for high flow under max burn conditions. Your use of a 50% port here would seem to contribute to that goal. The initial post-port "turbulator" area could potentially be a similarly small percentage of system size, hopefully allowing more rapid accumulation of higher temperature and turbulence, and more quickly attaining a clean burn. I tried to make a quick sketch of the images that have been forming in my mind over the past few months, but failed - I'll just have to carve out some time to set it up and try it out.
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Deleted
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Post by Deleted on Oct 27, 2017 8:18:06 GMT -8
How about this shape for the afterburner?
--------------------------------- | | | |---------------| | | |---------------| | | | ----------------------- | | | | | | | | | | | | | | | | | | | | | | | | ----------------------------------
With dividers made of glass the fire could still be watched.
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docbb
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Posts: 92
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Post by docbb on Oct 27, 2017 10:51:29 GMT -8
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Post by DCish on Oct 27, 2017 16:32:18 GMT -8
How about this shape for the afterburner? --------------------------------- | | | |---------------| | | |---------------| | | | ----------------------- | | | | | | | | | | | | | | | | | | | | | | | | ------------------- ---------------
With dividers made of glass the fire could still be watched.
I toyed with that. The internal glass tends to frost over with fine ash pretty quickly. It's is pretty hard to clean, too.
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Post by peterberg on Oct 28, 2017 0:13:39 GMT -8
I've also wondered if a large void on the other side of the port might be contributing to longer start-up times, requiring more energy to heat the entire space, and more flow to achieve turbulence. The next round of tinkering I'm planning is focused on trying to tailor that space to be as tight and well-insulated as possible to maximize heat retention and early production of turbulence, while still allowing for high flow under max burn conditions. Your use of a 50% port here would seem to contribute to that goal. The initial post-port "turbulator" area could potentially be a similarly small percentage of system size, hopefully allowing more rapid accumulation of higher temperature and turbulence, and more quickly attaining a clean burn. Brian, you are thinking about what I tried already. The height of the tunnel is now one brick flat and one brick on edge, but I also tried just one brick on edge maintaining the same width. That didn't work out as good so I tried the current height and a wider one, just as wide as the firebox and the brick on flat as the first one on top of the firebox. See my first video about how it looked like. That last one produced a quite nice double vortex but clean burning was achieved over a shorter period of time during the course of the burn as compared to the fire fountain configuration. Just to let you know your reasoning is probably not correct.
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Post by peterberg on Oct 28, 2017 6:25:49 GMT -8
I skimmed through the pictures on my iphone and found some relevant ones. First shows Donkey viewing the flames in the thingy and trying to sniff some of the gases that're coming out of that redicously short chimney while Mud and Patrick taking pictures. A very nice picture after dark while the thingy was running full tilt. Later the next day I took it apart but beforehand Tomás and Patrick took pictures and measurements of it. Four days later a new experiment was erected at Allerton Abbey, being a small cooking range connected to a bench of two half barrels. We tried to get it going on the last day without a proper chimney but to no avail, it was too much to ask. In order to have it started like that I should have added a bypass anyway, the whole of the build was soaking wet. The fire tunnel was built like a U-turn to optimize space and have different temperature zones to cook on. At the bottom right of this rather hazy picture is the port with the floor channel end clearly visable. Above that there's the opening to the small bell and bench beneath. There's also a viewing window incorporated. The cooktop was cut with a wet saw out of the glass of a dumped induction plate. To conclude, a picture of the design drawing which was made in one day. There are some glitches in there like some floating bricks and a bypass need to be added. Of course it could be built without the viewing window making the build less complicated and a better support for the glass cooktop as a bonus. I will amend the design later in November and post it here, it is all done with US format bricks in mind.
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Post by independentenergy on Oct 28, 2017 6:41:06 GMT -8
I think with a 6/7 meter chimney will work. I was thinking of an oven, bench with bypass
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Post by esbjornaneer on Oct 30, 2017 7:03:24 GMT -8
Wow, what a setup! Great to see that there should be less smoke back while re-fuelling this compared to the batchbox from 2 years ago. Are all the firebricks insulating/light weight? Or is there no need for insulation in this setup?
There was some talk about the glass in the video but it would be good to have it in writing: What are the specifications of the glass? Brand name? Source? Is it the same glass for the front as for the 'cooking plate'? (Moslty the glass I can find is rated to 750C but there was a mention of 1000C?)
Looking forwards to further develpoments.
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Post by peterberg on Oct 30, 2017 7:54:58 GMT -8
Brand name of the glass is Neoceram. Specifications 900º C, above that it'll expand but much less than borosilicate or Pirex. During dinner in the auditorium a glass mug full of tea that was left on the top glass of the batch box broke and all the tea spread over the very hot glass. Everybody was expecting the glass couldn't handle that but all the moist just eveporated and that was it. Most larger glass vendors will be able to sell it.
All the firebricks in the mockup were of the insulative kind. At home though the first experiments were built out of hard firebricks.
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Post by pinhead on Oct 30, 2017 8:24:04 GMT -8
Wow, what a setup! Great to see that there should be less smoke back while re-fuelling this compared to the batchbox from 2 years ago. Are all the firebricks insulating/light weight? Or is there no need for insulation in this setup? There was some talk about the glass in the video but it would be good to have it in writing: What are the specifications of the glass? Brand name? Source? Is it the same glass for the front as for the 'cooking plate'? (Moslty the glass I can find is rated to 750C but there was a mention of 1000C?) Looking forwards to further develpoments. Probably something like Neoceram Fireglass
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Post by independentenergy on Oct 30, 2017 10:51:23 GMT -8
there seems to be a difference between the core brick and those of the "U" duct. Do you think it's possible to build everything with non-insulating bricks?
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Post by peterberg on Oct 30, 2017 11:22:39 GMT -8
there seems to be a difference between the core brick and those of the "U" duct. Do you think it's possible to build everything with non-insulating bricks? I presume you mean the cooker pictures? The idea was to be able to use the firebox as an oven so this is built out of hard firebricks. It's possible to build the entire thing with hard firebricks but it'll take more time to get up to temperature. At this time I can't tell you the exact difference because it's too early days.
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Post by ronyon on Oct 30, 2017 18:14:38 GMT -8
! Hard brick, no insulation?
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Post by peterberg on Oct 31, 2017 1:50:05 GMT -8
Yes, that's right, see the picture at the start of this thread. One of the objectives is to see whether the thing would be able to burn clean without being very hot first.
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Post by esbjornaneer on Oct 31, 2017 2:08:19 GMT -8
I presume you mean the cooker pictures? The idea was to be able to use the firebox as an oven so this is built out of hard firebricks. It's possible to build the entire thing with hard firebricks but it'll take more time to get up to temperature. At this time I can't tell you the exact difference because it's too early days. It will be great, with time, to know at what stage you would use the firebox as an oven. I did that in my first build (because the intended oven did not get hot enough). The image I use is the Christmas roast veg and chicken from that year! But if I let the embers burn out completely the FB temp had cooled significanly with the primary air flow. If I left the embers in it had a tendency to over bake/burn the bottom of the bread and I always got smoke smells come out the FB door due to the height of the port hole. The smoke back issue is already sorted in this new setup. In my first build the FB walls were 4cm thick heavy firebrick with insulation on the outside. I guess it would have held heat longer if it had been thicker (laid flat instead of on edge) but it would also take longer/more wood to heat up to cooking temp. How thick would you consider making the walls of the FB for an oven effect? Great work! I have been yearning to build an outdoor stove for about a year but I think I will wait until this has been developed to go with this style stove. If there is anything that may be useful for the development that I could do let me know. (I don't have any testing tools.) PS Just remembered that I think MattWalker used an aluminium foil dome with insulation on the top of a barrel heat riser as an oven in some videos. How would that work on the ceramic/glass cook top while the fire is going? Or is that too 'heath robbinson' for what would be acceptable in the 'kitchen department'. I know I would be willing to cook on one of these but I guess if we want the average housewife to start using one of these stoves it has to be tidy enough for them Maybe too much stereotyping there.
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