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Post by Robert on Jan 5, 2014 13:36:30 GMT -8
Hello dear. This is a question regarding a trip wire thing. I was asked to lead a workshop on a RMH and i want to introduce folks here to the great trip wire innovation that has been made. But before i will do it i would like to be sure, that i understood everything correctly. I read the post made by Donkey which explains a lot, but just wanted to confirm i got it right (or wrong). Also in this post i would like to publish the sketchup design for the future builders, since i learned all of this on this wonderfull forum i want to give something back, for the future generation  So here i am right now. I placed the second brick and made this arrow shaped trip wire. The depth is 8mm right now (should it be made little bit smaller???) And a question. 1.As i understood, this tripwire thing will work only together with the P-Plate? Can you please explain why? Since i wanted to make a doors in the feed tube, but then if i need to use a p-plate than i will need to quit the doors. 2. If this invention is really boosting up the efficiency of our stoves? What it actually does? 3. What tools have you been using to create this shape on the brick (question for Donkey and others who did it). Here is the first version of a sketchup file. When i will finish, i will post a full version. The workshop is going to happend 7th of February. Keep you fingers crossed HERE IS THE SKETCHUP DESIGN: trip wire.skp (92.48 KB) |
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Jan 5, 2014 14:53:16 GMT -8
3. What tools have you been using to create this shape on the brick (question for Donkey and others who did it). I used a 4½" grinder with a diamond blade - tested it first on an ordinary brick then on the firebrick. |
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Post by Robert on Jan 6, 2014 0:51:43 GMT -8
Hey morticcio. Can you share the experiance? Did you noticed a difference in running your stove with the trip wire? And are you using it together with P-channel as well?
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Post by peterberg on Jan 6, 2014 2:45:54 GMT -8
I placed the second brick and made this arrow shaped trip wire. The depth is 8mm right now (should it be made little bit smaller???) Yes, actually it could be 5 mm or even less. It's specifically targetted to disruption of the laminar stream close to the ceiling only. Frankly, in your situation I would implement the trip wire in the first brick, bringing this closer to the p-channel inlet. 1.As i understood, this tripwire thing will work only together with the P-Plate? Can you please explain why? Since i wanted to make a doors in the feed tube, but then if i need to use a p-plate than i will need to quit the doors. This trip wire will work much, much better in conjunction with the p-channel thingy. Creating mini turbulence on its own won't suffice, you have to add some oxygen rich air as well, preferably heated. The p-channel on its own will make a difference but it is markedly better in conjunction with the trip wire. How the air is fed into that spot isn't terribly important as long as the main inlet doesn't influence this secundary inlet. So, a door could be used still, the secundary inlet in the door frame for example. 2. If this invention is really boosting up the efficiency of our stoves? What it actually does? What it actually does? In broader terms: it will confine the combustion almost exclusively to the burn tunnel, creating a smaller and thereby hotter environment. Hotter, limited feed of heated fresh air, closer to complete combustion in a shorter time? |
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Post by mbxxxxxx on Jan 8, 2014 11:14:44 GMT -8
peter: have you quantified the improvement in efficiency? I'm looking for a estimated percentage increase in overall efficiency.
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Post by peterberg on Jan 8, 2014 11:20:02 GMT -8
My target has been to improve combustion efficiency, overall efficiency is another.
No, I am unable to quantify efficiency improvement.
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Post by patamos on Jan 9, 2014 15:04:17 GMT -8
I am getting ready to do something similar and have been researching back through old to determine what conclusions were reached about Peter's channels at both the front and rear of the feed tube, most appropriate heights of each, and the value in preheating the front (closest to the heat riser) but have not yet located the info. Can anyone shed light on this and how it may or may not be affected by the trip wire in the first or other bricks?
Many thanks for all the experience folks are sharing on this amazing forum!!!
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Post by patamos on Jan 9, 2014 15:20:43 GMT -8
Further refinement of my P-channel question:
Would cutting vertical notches in the side walls of the feed tube nearest the heat riser, and sliding a slab of 1/4" metal down into it to create the P-channel be an effective strategy? Or are the width/depth proportions of the channel more crucial?
Also, does the P-channel need to be covered when the door is closed? I will have 18+ ft of vertical flue above my heater, much of it wrapped in cobb, so it will likely want to keep pulling a fair bit.
many thanks
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Post by peterberg on Jan 10, 2014 8:53:45 GMT -8
You could try the notches, but the p-channel should be 5% to 6% of the feed csa. Also, the metal plate will probably deform when heated up, that's why my suggestion would be use folded sides in order to stabilize the plate. The width/depth proportions aren't crucial to my knowledge. It's just that 5% csa divided by the width of the feed. Oops, your plate is 1/4", that's a hefty piece of metal. Maybe you could get away with it, you have to try it yourself.
When using a door, it's best to have the p-channel covered as well. May I suggest you channel this through the door frame and use a separate slider or similar to close it off?
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Post by Robert on Jan 10, 2014 12:04:14 GMT -8
I am getting ready to do something similar Welcome patamos. Please share your work also in this thread and add some photes while you start to make your project and you will come with some solutions. Its kind of new concept for us newbies, and i think it is good to have this thread with all explanation on how to do the J-Tube with TripWires and P-Channels if we will do the core from bricks. Peter. when i was looking at the Dragon Heater version of a stove it seems like they do not cover the feed and the air intake at all.  I am thinking wheter to make it some kind of lid just to cover the tube, and some kind of plug to close the air intake. making a door with the channel incorporated its seems to be a difficult job for me. And if i would me making it, i would like that the door would be closing the feed tube and channel at once. Anyway this is what i came with. i changed a little the design. Moved the brick closer to the feed tube, changed the slope of a trip wire to the 6mm, and add a basic frame with the channel, 6% of the feed CSA.. Is this is what we want?  If anyome else will come with the solution for a neat door. please share. |
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Post by peterberg on Jan 10, 2014 12:34:25 GMT -8
Robert,
The Dragon Heater design sports an actively cooled p-channel and because both openings are in the same plane those can be covered by means of a large brick or something like that. The feed you've drawn has one flaw: the plate has to extend above the feed this way, otherwise the main inlet will dominate entirely. This effect is not the same in the DH design because the p-channel hole is further away from the feed itself. Another deviation: the plate doesn't hang down the tunnel's ceiling, that is necessary in order to get the much needed suction at that spot. The overhang should be about the same as the width of the gap.
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Post by patamos on Jan 12, 2014 10:25:21 GMT -8
Thanks Peter,
To clarify your response to Robert's sketch up, are you saying the top of the plate that separates the feed tube and p-channel had best be the same height as the top/ceiling of the feed tube, and the bottom of the plate the same height as the ceiling of the burn chamber?
If the entry surface of the feed and p-channel is flush, then i would be most inclined to want to cover them both at once. Is there any advantage to having a separate adjustment for the p-channel?
many thanks
well being
pat
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Post by peterberg on Jan 12, 2014 10:39:00 GMT -8
To clarify your response to Robert's sketch up, are you saying the top of the plate that separates the feed tube and p-channel had best be the same height as the top/ceiling of the feed tube, and the bottom of the plate the same height as the ceiling of the burn chamber? No, just the opposite. The plate should be about 2" higher than the top of the feed in order to avoid complete dominance of the main inlet. In addition, the bottom end of the plate should hang lower than the ceiling of the burn tunnel in order to create a slight vacuum behind the plate. |
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Post by Robert on Jan 13, 2014 14:44:36 GMT -8
thank you Peter for letting us understand the principle behind the tripwire and p-channel thingy. i hope i am understanding the directions you are giving. here are the corrections:   so it is important that the p-channel is separated from the feed tube? work on the design in progress. next i will try to add some sort of a system that i can see on the DH design. thank you for your comments. i hope that publishing this design will help people to understand the changes you have brought to the scene |
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Post by Robert on Jan 13, 2014 16:34:13 GMT -8
Actually i forgot about the third very important thing. the kick-tail at the end of the burn tunnel. i remember we were speaking about that with Peter, and i remember he suggested the shape of a bowl we had very interesting discussion on the pressure which is happening at the end of the burn tunnel... Peter could you please explain this phenomena a little bit. i think a lot of people should be aware about those 3 changes that has been made. the simpliest way of doing this while building the core from the brics would look like this:  is that makes sense? any suggestions about the size? angles? |
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