Just tryin to be helpful...after the port may work if adding secondary air for turbulence and thorough combustion. There are others, metal, that have similar set ups for complete combustion. The balance lies in not allowing too much secondary air. The metal builders have also experimented with shapes for turbulence after the port.
Post by matthewwalker on Nov 19, 2014 14:54:52 GMT -8
Here's version 3 and 4. I've been using 3 for a few days now with great results. The shape is obviously not what I imagine as optimal, as you can tell from my earlier posts I suspect the cylinder shape is useful. Still, it has been performing very well, and was the only material I had on hand that could get me the 2.5"sq. I wanted to test.
So, now I'm onto 4. We will see how it does. It's I.D. is 2.25"x1.25" for a total of 2.5"sq. I may end up blocking the front exits and drilling an exit right before the vertical, since I liked how that mixing seemed to do on v2. I'll try it like this first.
Totally AWESOME, Matt!!! Soooo many possibilities/questions! Great job and the graphs are so impressive. Your tube on the left (1st page of thread) looks as well formed as a pre-shaped bbq burner.... I like everything about this tack your on. I've been recently daydreaming about a gas range style burner/ eye, at the port or in some part of the lower riser, maybe even some sort of rotating valve to introduce pre-heated secondary air in a circular or pulsing fashion- probably fanciful thinking, considering my batch box is still struggling to get built in the basement. Can't hurt to dream, your efforts prove that!!! Thanks for sharing and awaiting further results/posts/pics, Eric VW
Last Edit: Nov 19, 2014 19:10:57 GMT -8 by ericvw: premature posting!!!!
Matt, Excellent work my man! I love a guy that puts his ideas to the test! I fear that with your small tube, most of the air injection is being used up in the first third of your slit. A larger diameter tube as you mentioned should act like a manifold and give better results. If you were to connect your air supply to the mid point of this injection tube, it would minimize the pressure difference between top and bottom.
Matt, Peter, In the pictures you both have posted, they show eddies(turbulence) behind the tube. I don't believe this is the case. There are two reasons for this.
1. The gas flow is not straight in our batch box, it is converging towards the back, minimizing the low pressure zone.
2. You are injecting air into the low pressure zone making it a lot less pressure.
With both these situations in place, I would think there would be hardly any eddies/turbulence behind the tube.
To increase this low pressure I suggest having two slits in the same tube. Instead of straight back, rotate them 45 degrees from center so they are facing each tapered wall directly. This would make the volume behind the tube a low pressure zone.
I hope I'm not stepping on any toes Matt. It feels like I'm injecting a lot about your idea. I'm enjoying this thread! Terry
Matt, The vertical air slot of version 4 looks like it's quite large as compared to the csa of the pipe. I'd suspect the top half of the pipe won't eject any air because of that. There's obviously a pressure difference between the top and bottom end of the slot, I'd second Terry in that.
As a suggestion: while the version 2 and 3 were very succesful, could it be that the lower bigger hole the most important air injector is? Maybe you could stuff the top half of the slot with superwool and try that configuration. When this yields satisfying results the next step would be to stuff the slot altogether and use the bottom slot on its own? Half the vertical slot would simplify things greatly already, with or without the top half of the pipe. Let alone omitting the vertical pipe end altogether.
Post by matthewwalker on Nov 20, 2014 9:08:43 GMT -8
Yes, yes. Thank you both, this is exactly why I posted here while I'm still experimenting rather than holding out until I had it all figured out or gave up.
v4 is in there now, as of last night. It's performing pretty much the same as v3. I had a few hiccups on starting, but I'm sorting those out and it's operator training, but it still is making those long flat CO graphs. Very promising.
Terry, Peter, I had been thinking along the same lines, that the upper half of the slot is probably not doing much. Terry, I love the speculation on where the low pressure is, I tend to agree. I like the idea of the two slots, I will try that. Peter, I can easily obstruct part of the slot, I will try obstructing the upper portion, and the whole thing as well. Good ideas my friends, thank you!
why not to drill? first hole 2mm second hole 3mm and so on. why the channel on the floor? why not ander the ceiling?
I might try holes, I had thought of it, but it's easier to measure a slot. Peter, you are right, the slot is 8"x.25" = 2"csa, while the tube is 1.25"I.D. so only 1.22"sq csa.
As for the ceiling, well, it's easier to set it on the floor. Also, this thing is getting red hot in the coal bed, I think that's helping consume CO way out in the end of the burn. But, yeah, it could probably be done a lot of ways.
Could've fooled me Matthew! Shilo, I had a similar thought- vee shaped over the vertical rise of the slot. Smaller at the bottom and increasingly wider to the top of the slot? I also liked your suggestion of drilled holes, like a burner on a gas bbq, just increasing in diameter as you go up. Matt, in your above vid, what is it that looks like a can above your new design? And is it the wine, or are the flames licking up and back towards the center of the box? U do have a top glass in your batch, no? Either way, I dig it! Eric VW
TexasGonzo: Sooooo glad I found this site! Its always rewarding to find such a super group of folks! To any and all, feel free to PM me anytime. Thanks for having me!
Mar 11, 2019 18:56:41 GMT -8
jlmtech: GADGET: CONSIDER USING A JET PUMP INSTEAD OF A BLOWER FAN TO INDUCE DRAFT; NO CLOGGING.
Mar 26, 2019 8:19:28 GMT -8
michaelegan: i am unable to open the sketchup files on my mac. I used sketchup a few years back but apparently the company now requires a subscription. does anyone have any advice/instructions on how to use the program or how to view pictures without spending money?
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mannytheseacow: michaelegan: download AutoCAD student version for free... import .SKP
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topbaza: hi everyone, been searching all over net and this is were i need to be i think!!
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ahansen: photos under 1 mb not possible?
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deadstarsstillburn: Hi there. I was directed this way by folks on the Permies.com website and am hoping I can get some information on how a total newbie can get started designing, siting, building, and not-dying-in-a-horrible-house-fire with a new RMH in a 160-year old home
Oct 21, 2020 6:52:10 GMT -8
deadstarsstillburn: The people over there recommended either a 6" batchbox or an 8" J-tube. I don't know what those are but am going to try to figure that out. What I need is a blueprint that I can scale to fit the need for my house. I have something likne 5000 square feet
Oct 21, 2020 6:53:00 GMT -8
deadstarsstillburn: but I do not need to heat all of it by any means. probably only need to heat half of that, maybe less.
Oct 21, 2020 6:53:15 GMT -8
deadstarsstillburn: moreover, the house has 3 storeys (large attic) so I assume if I get very efficient heating on the ground floor, that will go a long way toward heating the upstairs as well, no?
Oct 21, 2020 6:53:59 GMT -8
BenAlexanderT: Happy new year everybody. I wish you the best
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Solomon: Anybody in Southern Oregon, in Jackson or Josephine counties?
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gnomedome: i realsie this is from 2009
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gnomedome: i realize this is from 2009 id love to see the photos from this ..as im looking to build a sauna soon similar to this .... if anyody sees this post firstname.lastname@example.org..... the photos in this post did not show up
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