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Post by patamos on Mar 9, 2022 10:14:13 GMT -8
Ya i've been playing with it a bit. The original dimensions of the middle shoe were 4" tall by 7" wide. The most recent iteration of the dual port set up was two openings at 4.5" long by 1.75" wide.
When I switched to a central aryan port I went with 2.25" wide by 4.5" long (left it at that so I wouldn't have to deconstruct the ceiling of my firebox). Although it burned very clean it also wanted to backdraft out the firebox door a bit; so to clear the restriction I raised the middle shoebox ceiling to 4.5", and opened the port a bit by sliding the bits of kiln shelf (that shape the port opening) forward to make about 3/8" space across the back floor of the middle shoe. In plan view it looks like an uppercase 'T' with a very thick stem and very thin line across the top. That combination of tweaks has solved the back drafting issue, and when we get into peak burn the flames jetting up the back wall create a forward pressure on the dual rams horn that pushes the flames up into the upper shoebox. When things are really cranking the trajectory of the rams horns is about 45 degree angle.
I should probably widen out the sidewalls of the middle shoe to the specs for a 6" system you have shared. And maybe close off that gap across the back to see what happens. But that will be another day. For now I am just thoroughly impressed with the improved performance. I think it has much to do with the one port offering optimized combustion earlier and later into the burn. With two ports the size I had them, the phase of optimized combustion was much shorter.
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Post by patamos on Mar 8, 2022 12:23:37 GMT -8
Hi Folks,
Just wanted to say that I finally got around to converting my tauran dual throat triple shoe box to a single central port aryan, and it is burning WAY cleaner. The whole middle shoe box is now glowing bright orange by mid burn, and the prior tendency to over-fuel every now and then is gone. I guess we all kind of knew this aryan triple shoe set up was cleaner. So I'm just adding in some anecdotal evidence. Everything else about my stove's build and my fueling habits has remained the same, but it really is now burning way hotter and cleaner.
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Post by patamos on Dec 22, 2021 22:12:35 GMT -8
Beautiful work Trev!
And the slower burn rate is giving your mass longer harvest/residency times to boot.
I'm curious to hear your thoughts on ideal routing for the secondary air?.. (Thinking of how to retro fit something into a few recent builds...)
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Post by patamos on Dec 20, 2021 20:55:42 GMT -8
Having removable plates is an important factor to avoid warping, in my case I have found that by having a central plate, my 10mm mild steel top becomes slightly concave but the sides dont move. So I dont even need to fix the plate down, it just sits on a rope gasket. One cook-stove heater i built with a mid-size firebox and a mild steel cook top 16" x 20" x 1/4". Every firing it warps up about 10mm and you can see into where the flames are rounding the top shelf. It was only meant to be temporary til I found a ceramic glass top, but the clients liked the dynamic, and it has never smoked back on them in the 8 years since.
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Post by patamos on Dec 20, 2021 20:51:13 GMT -8
Ya cast iron anything is worth holding onto. Even small sections might become a griddle for something somewhere
Prices are USD, and to get them into Canada you have to sort out the duty and customs yourself. Easy to do in person at the border, but all kinds of emails, phone-calls, and scans/faxes otherwise.
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Post by patamos on Dec 20, 2021 13:06:10 GMT -8
The cook top is a cast iron unit with frame, removable deck and two removable disc/plates. I bought this one from max Edelson (firespeaking.com) who is the N.A. importer and distributor for a Chinese company called 'Fireway' The firebox door is also from them. Both part of a larger shipment I had arranged 2 years back. Pretty good quality all in all.
Can't imagine what the supply line is looking like these days. I hear talk of highly inflated bidding wars for cargo space on sea-containers
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Post by patamos on Dec 17, 2021 22:56:58 GMT -8
Ya, all that for sure this taller throat, now pushing 3+ inches thick, also seems to make that flame want to jet straight up and crash pretty hard into the ceiling. So the palm tree effect is being exaggerated. And I recon y'all ought to know that at any time i catch even a glimpse of complex geo-physical equations my eyes instantly glaze over... But when i think of it in terms of fluvial geo-morphology everything makes gut sense to me. Interestingly enough, I recently replaced the stumbler in the middle of my (own heater's) port with a wider piece of kiln shelf. This has made for by far the biggest restriction yes, bring the dimensions of my exit down to a pair of 4.5" x 1.5" . And lo and behold, the pull was instantly 20-30% stronger. So ya, it all makes sense one way and another... Anyway, I just today narrowed the port on Brent's firebox to 6.5" x 1.75" and something just wasn't right no matter how much i tinkered. Then... I happened to open the front door (of the very air tight building)... and THAT was the answer. not the first time its happened either...
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Post by patamos on Dec 16, 2021 19:50:41 GMT -8
Ya more or less air along the sides can be just a metal sheet that is 1" narrower than the ashbox roof opening ; with splits as struts on both sides in the front and back of the ash box that can hold the deck up. Maybe do that part in clay-sand mortar so you can adjust if necessary... Also, I have about twice as many holes each end. kinda 4 staggered rows worth with 1/2" to 3/4" spacing between them. This is just what came to mind in getting a long narrow firebox to work well enough. Could be there is some variation in ratios that might work better... have fun
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Post by patamos on Dec 15, 2021 10:17:17 GMT -8
I'll second that. Very hard to tune otherwise. Also, with coal-burn-air from the ash box you will get fairly even distribution; but with a small port at the front the faster air flow will likely burn the coals near the front first and thereafter bypass through that gap into the open space. When the fire is roaring secondary air will mingle well enough near the ceiling port. But with coals, you want to aim the air right at them.
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Post by patamos on Dec 13, 2021 13:29:35 GMT -8
Wow. Checking in 5 years later (I popped in for a few weeks on page 12) and there you are Trev and Patamos still advancing, experimenting and helping out folks. *hats off to you sirs* My Vortex stove you helped me design back in 2016 is still going strong and letting me cruise through the alpine winter. Thanks for that and I'll keep sending people here, though I really should read up on all the progress myself. I'm almost itching to build another one and improve it with your insight. Now just to find a place that needs one... Thanks for the mention. But really it is Trev who has been doing all the hard work. I just chirp in now and then and ride on his coat-tails I've just sent the latest Vid of the latest 'vortexy' build over to Trev so hopefully he can load it up shortly. Regarding CFB hardeners, I'm guessing that products such as vitcas rigidizer that are designed to do this work will work best. As mentioned earlier in this thread, the issue of flaking that i experienced with super 3000 (refractory thin set) probably had much to do with the mass of the surface skim-coat mass expanding and contracting, leading to gradual delamination from the softer CFB substrate.
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Post by patamos on Dec 3, 2021 10:08:39 GMT -8
Primary and secondary all in one. Air control in the ashbox door or with a damper on external air supply routed through the ashbox. There also tends to be a small volume of air intake low on most Pisla doors, mostly as a 'airwash' for the glass, but it amounts to about 1"sq at best. As with many masonry heater builds for clients, Alex (and many of us really) try to keep the amount of fire tending to a minimum. It can be a challenge enough getting people to store wood properly and load/light effectively... Alex came up with this firebox design (see: www.stovemaster.com/html_en/drawing_for_self.html) in response to recent pressure to build eco-boxes (with air vents all up and down the side and back walls). As with all kinds of 'group think', building officials in Europe saw that the Austrian ecobox was getting slightly better numbers than bottom air feed systems, so began mandating eco-boxes. Trouble is they are relatively difficult to build and also quite fragile. Further, every seasoned heater builder knows that how we load and light in a big firebox (top down with drywood etc...) is a much bigger factor in combustion efficiency. Also, with a solid flat floor the eco-box fares poorly in the coaling phase, so they advise closing off the air supply to starve that phase of air, and use the coals in the next burn. Works well in theory, but once your door gaskets are a little worn... or if operator forgets to close air supply at that stage... well, that is when the air from a v-floor works way better. So, all that to say, when various real-world factors are weighed in... including the likelihood that many operators are just going to 'load, light and leave'... the real-world improvements with an eco-box are a bit of a mixed bag. So, Alex, being a no-nonsense kind of guy, and being a very experienced builder who has seen and tried all kinds of designs over the years, came up with this design and had it tested with Norbert Senf's Condar PM analyser, to discover it is pretty much as clean as an eco-box thru the flame/burn phase - but waaay more rugged and easier to build. Alex is also the fellow who has worked harder than anyone to promulgate the Russian Bells in masonry heaters (see: www.stovemaster.com/html_en/designsystem.html); and has led a number of studies on the relative harvesting efficiency of bells vs flue runs. btw. he is also the distributor for Pisla hardware in Canada Can you tell I have a lot of respect for the guy?
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Post by patamos on Dec 2, 2021 22:03:30 GMT -8
Trev, your discovery regarding air intake low across the front echoes (somewhat) the design Alex Chernov arrived into for his masonry heater fireboxes. He places a Pisla 4" x 16" grate across the front floor, and a much smaller one 2" x 7" across the very back floor. I've built a few heaters this way now and find it burns pretty much as clean as an Austrian eco-box - with the added advantage that during coaling phase you can rake the coals forward and back onto the grates for that turbo effect.
We've been tweaking the air flows on that last vortex I built. Lots of downstream harvest and restrictions to account for, but coming along. Will send a video soon
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Post by patamos on Nov 30, 2021 21:23:02 GMT -8
Why is the top chamber surface area to volume ratio important? Over the last 3 seasons I have been mostly experimenting with different size, shapes and configurations of the top chamber, stumbler and exit port. When I built the first experimental model in my garden in summer 2018, I discovered that a restriction made it more stable and less prone to overfueling. Originally this was the gap between the front of the afterburner shelf and the inside of the glass, but was later moved into the top chamber as the glass was getting burnt. A restriction only works so far though, as over a certain level the bottleneck starts to slow down the gas flow too much, which itself makes the stove overfuel from lack of air. In December last year I noticed that making the top chamber exit squarer, somehow made it work better. It turned out that in the process of changing it around to fit in the square port, I'd unintentionally increased the surface area of the top chamber, and that was what was causing the effect. I experimented with various ways of trying to make use of this discovery, but it wasn't until late last winter that I realised that I could just do away with the restrictions of the stumbler and exit port altogether and use the resistance of the increased surface area instead. Earlier this season I experimented with increasing the SA:V to the maximum possible level to see what that would do, it created a very stable burn, but also slowed the gas stream down too much. By increasing the primary air and gradually reducing the top chamber surface area, I managed to find a perfect balance that holds the vortex nicely in the afterburner and resists overfueling and thermal runaway. I think this discovery is the crux of the biscuit. For anyone building a vortex stove you will have a unique set of variables, eg. downstream restrictions and harvesting dynamics, chimney height relative to roof and surrounding vegetation, altitude, etc... So playing with the SA:V ratios in the top chamber is the way to dial flow rates up or down, and for those of us without testo or condar PM gear... the shape/pattern of the double rams horn is a good indicator of how clean the burn is. Trev, you are a great researcher and teacher.
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Post by patamos on Nov 15, 2021 20:07:31 GMT -8
Hi Pat,
The fellow who runs the masonry supply Shop in Kamloops (Frank D'something Italian...) is a great guy, but will charge you all the freight and then a mark up. So you are better to source from Alphatherm and get it shipped to someplace near you that has a forklift. For doors and hardware i go to either Alex Chernov who distributes Pisla in Canada, or Max Edelson who distributes 'fireway' from China. For years now I have been planning to get an qxy-acetaline rig and start carving off the front sections of defunct metal box stoves... but that is still hovering on the list... For clay bricks i'd suggest putting an add in the Kamloops paper looking for old chimney bricks. If someone is pulling down an old house you could probably offer to haul a few hundred of them away for free. We can PM to discuss other things you might need and where you might find them.
Trev, thanks for uploading those pictures. Tiny 300sq ft cabin. Super tight manouvering cuz it is already full of furniture and stuff. Fairly dense mass walls (scotch-broom light clay) so lots of harvesting mass. Previously had a barrel rocket with the beginnings of a bench, knowing we were going to extend it out to a two seater with decent cookstove. Also had a 2" slope in the as-yet-unleveled floor in the mix.
I love working with clay and clay brick, and do so in areas that i know it will never reach 500c. All of the knowledgeable old timers I have asked say that'll be about 5 feet downstream from the firebox... but I err on the side of caution. Where hotter than 500c, and/or occasionally cycling above 250c, i switch to firebrick or clay flue liner core.
With firebox i go double wall with ceramic blanket.
Exhaust mainfold i use firebrick lined with splits of IFB, glued with super 3000 (sodium silicate and talc putty).
The whole heater is covered in cob plaster. And most of it also has 4.5 oz fiberglass mesh embedded in the outer 1/4" of browncoat. Thinner wall sections (like the backrest on this one) I also embed the fibermesh on the inside channels, and include about 25% S-3000 in the mud.
All in all this is a hybrid technique between - cob mass, - old school single-skin clay-brick and clay-sand mortar, - 'double skin' with fibrous parge coats, and - modern double wall... with 2 or 3 stages of transition from one end to the other. The trick is knowing where to expect thermal expansion and let things move around within a shell (double wall with padding)... and where to snug things up tight...
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Post by patamos on Nov 14, 2021 19:30:12 GMT -8
Just checked the link. might be glitching, so i have loaded it up on my website: amosclayworks.ca
I'm hoping to wrap that backrest sometime this week, so am keen to hear what y'all think
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