Vortex Stove

[patamos]

Curious, roughly what % of the burn does the double vortex stay formed when your fuel load is optimized? And how much, and when does the upper glass ever take on soot after the peak burn is winding down?

Also, re combustion, i'm not sure if i mentioned this a while back, but once i installed the Pisla 412 ash door with about 8"sq. of air intake my burns improved dramatically. Especially the big yellow grundofen that had puff back issues we thought were due to the corrugated 6" exhaust routing. Could have been I had less clearance/leakage around the firebox door and frame than in your original set up. But once she could fully breathe in the burns went full tilt. I know much more than 200% O2 isn't going to be of benefit, but with the whole thing going up at once we are dealing with 'all in one' burns after all.

I thoroughly respect the efforts Peter and Matt and co are making to dial in the two stage process. I just find myself building for people who are less interested in the whole process, and therefore less interested in the extra aspects of routine (and smaller viewing window) involved.

[Vortex]

Hi Pat, The double vortex starts as soon as the flame is going through the port, about 2 minutes after lighting, and lasts until the start of the coaling phase.
There is never any soot or smoke deposit on the afterburner window after about 10 minutes into the start of the burn, it stays clear right through to the end.

I have a little over 8 square inches of primary air on the new stove. I underestimated the amount of air my old stove door let in through that 2mm gap around the sides and top. When I made the door for the new stove, I made it with the same size primary air port as the old one but with an airtight seal. It pulsed like mad until I cracked the door open so that there was a few millimeters gap around the edge. I ended up making a 2 position door catch, so it has closed but with a 2mm gap, and closed airtight.

[martyn]

Hi Vortex, I love your design however this thread is now huge!
I am having problems finding the basic construction dtails and dimensions.
Could you please either direct me to the appropriate post or re post the more critical sizes ?
Thank you 😊

[Vortex]

Apologies Martyn, None of my pictures are working at the moment because they're in the process of being moved to a new host. They should all be back up in the next few days. This is the basic dimensions of my present setup. Discussion of it starts on page 28 at this post: donkey32.proboards.com/post/30273/thread

[martyn]

Thank you, I can wait for the pictures to return.
So the center plate is adjustable for hight but how far away from the front glass does it end and where about is the 6” exit pipe situated in the roof.
If it is not to much trouble I would love to see a side elevation sketch :-)

[Vortex]

The center plate is fixed at a height of 4-1/2". The adjustable part is the size of the gap between the front end of the center plate and the inside of the glass. That sketch was just intended to give the basic dimensions of the firebox and afterburner that I ended up with from the experiments in my garden last summer. It is meant to have a mass to capture and store the heat from the hot gases that exit from under the cooktop.

The core seems to require some back pressure in the system to work correctly. A large mass creates some back pressure. Reducing the adjustable gap can also be used to creates some, the smaller the gap the more back pressure it creates, so the gap can be used to tune the core to the mass it's heating. If there is no mass (as in the sketch of my garden stove above), then it would be the smaller size, and if it's on a large mass with many twists and turns, then the wider size, most would be somewhere in between.

[Vortex]

The probes I ordered for my digital thermometer arrived today, so I installed them into the front and rear right-hand side of the afterburner.

I wanted to get an idea of the temperature in the afterburner and also the temperature behind the glass where it's getting etched, which I discussed on the "Edjumacate me about using glass windows" thread HERE.

The rear probe is visible sicking out of the lower rear right-hand side, just above the piece of steel that forms the 45 degree angle. It glowed orange through most of the burn and the temperature went up to 921*C / 1690*F

The front probe behind the glass went up to 730*C / 1346*F. That's well within the operating temperature of the glass, but the reading may be low because the probe was to near the bottom. I'll raise it up more towards the middle for the next test.

[chrisz]

Can this core and afterburner be adapted to a larger oven?

I like the glass fire box door for viewing the fire.
I like the glass for viewing the secondary combustion.
Is it an option for the secondary combustion chamber to be larger so that is can better function as an oven?

cz

[Vortex]

Hi Chris, If you made the afterburner larger you'd lose the double vortex. You'd have to wait until the fire was out to use the afterburner as an oven anyway, so you might as well use the firebox. You just need something to put in to stand what you're baking on so the embers don't burn it from underneath. I use an old fire grate.

[chrisz]

Understood.

In your estimation, could I build an oven with high mass after (most likely directly above) the afterburner, that would also function as the stoves heat sink?

[Vortex]

I haven't done it but I think it should work OK. The exit temperature of the afterburner is around 750*C / 1380*F. You would lose the cooktop of course. The top of the afterburner would be the base of the oven, and the exit would have to be at the bottom rear, so the oven was a bell. It would need to be constructed out of dense firebrick or castable, and be well insulated on the outside.

[Orange]

Mar 22, 2019 12:52:36 GMT -8 Vortex said:

maybe to add 4 small pieces slightly protruding out in the middle of the firebox so you can load the metal tray just like in a regular oven?

[Ramunas]

my old experiments
youtu.be/pnYXO3hlxIE

[fishalive12345]

Hi Vortex (Trevor?),
first of all I'd like to thank you and everyone else who shares their ideas and findings on proboards.

I'm planning a first build based on the new version of your stove as far as the combustion element is concerned. I'm going to try to include elements from other designs as well and hope to get some feedback on my ideas about the heat storage element and a switchable black/white oven. I plan to start a new thread about my build and ask for advice and suggestions about it there.

But first of all I have some questions about some aspects of your design.

1. How does your secondary and or tertiary air work?

2. What is the height of your cooktop space? Is that dimension optimised?

3. What is the thickness of the shelf in the aryan shoebox secondary burn chamber? What do you think the best material for this piece would be especially in view of the fact that it can be moved in and out? Do you have it sitting in slots at the side and an extra deep slot at the back?

4. Am I right in thinking that the depth of the secondary burn chamber is the same as the firebox?

5. What shape and size is the exit from the top chamber into the cooktop space? Is this important?

6. My last question concerns the heat recovery element of your stove, the flue run layout of your first stove is clear from the photos you posted but I don't understand what the layout is in your current version. Do you think your flue layout is applicable to normal bricks or only to the special heat storage bricks that you have used?

[fishalive12345]

I forget to say thanks in advance.