Vortex Stove

[Vortex]

I use these, they're called 'Quick Hinges', designed for use on wooden window frames. I just cut off the threaded part and weld the remaining parts on. Bottom part has a post and the top part has a socket that fits over it. Means you can easily lift the doors off to work on them.

[1967gto]

Sorry for not being clearer.  How do you connect the door frame assembly to the stove?

[patamos]

Drooster,

I think somewhere back int eh early pages of this thread there is a diagram showing what you are considering. How to optimize turbulence in the elbow of the throat. With secondary air jetting into that area via a horizontal slit and with insulated core rounding the corner above the throat, we are basically getting into Matt's pre-port secondary set up - only the whole operation is sideways.

There are bound to be differences due to a relatively larger port and much less of a downstream rockety pull sans optimized heat riser. And one consideration with regard to adding heat risers is the gain in height of a stove top cooking surface if you still want that...

At the same time though, this fire box also has potential to mimic the secondary burn processes of high end metal box stoves. In both Trev's and my experience, the slow gassification mode is a boon for cooking versatility and generally enhances the heat harvest.

my 2 cents

[Vortex]

Thanks Pat. Not sure which diagram you're referring to, this is the closest I can find (could it have been in an email or another thread?):

 

That one doesn't show the secondary air. I was thinking along the lines of this rough drawing, where the secondary air is shown coming in through the top of the firebox and edge of the throat:

Nov 12, 2016 13:59:29 GMT -8 drooster said:

I want some hints on the cross-section shape of this upper burn tunnel, but if this is early days I guess I'll find out

Drooster, The diagrams above are roughly the layout I have in mind.

[Vortex]

Nov 16, 2016 13:05:19 GMT -8 1967gto said:

Sorry for not being clearer.  How do you connect the door frame assembly to the stove?

No problem. In this diagram where it says 'Door Frame', the frame is either screwed through holes into the masonry or the frame has threaded holes so bolts can be screwed into holes in the masonry. I've used both ways without any problems. Aluminium foil can be used to pack the holes out or give the screws something to bed into.

[1967gto]

Thanks Vortex.

Have you tried making the entire core (except maybe the floor) with insulated refractory? I made a rocket stove with refractory and perlite, which works great but is not very durable.

May sound foolish, but what's the difference between low grade refractory and regular refractory?

[drooster]

Thanks for the info Patamos & Vortex.
I want to gain as little height as possible while still getting a very hot 'riser section'.
I might build the lower part (firebox) solidly first and intentionally make the upper part disassemblable (is that a word?) to try different layouts.
I have some nice stainless 1" pipe with which I intend to lay in a number of secondary air channels and open/block them as required, according to testing.

[patamos]

Nov 17, 2016 3:55:16 GMT -8 Vortex said:

Nov 12, 2016 13:59:29 GMT -8 drooster said:

I want some hints on the cross-section shape of this upper burn tunnel, but if this is early days I guess I'll find out

Drooster, The diagrams above are roughly the layout I have in mind.

Ya Trev, this diagram is very much what i have been thinking of too.  The dotted material being ceramic fibre board.

Might also work if the top deck of the fire chamber is made of the same.  And the secondary air is preheated from gas flow over top.

I have another build coming up so i will give something like this a go.

[Vortex]

Hi Pat, I updated the picture to make it a bit clearer what I meant. The secondary air is shown entering between the dense refractory roof of the firebox and the insulating floor of the secondary burn chamber above.
I wonder if the firebox roof was all insulating refractory whether the stove would lose some of it's ability to gasify. I decided for my first test to do half and half and see how that goes.

Drooster, my plan is to make the whole firebox and 'riser section' / 'secondary burn chamber' disassemblable (nope, my computer says it's not a word:)

Something like this, using 1.5" slabs of dense and insulating refractory back to back, (so they equal the 3" thickness of my existing stove walls). It'll all be held together inside a metal framed box like my present setup but complete on all 6 sides and airtight, so there's no need for fireclay between the parts. Should hopefully make it a lot easier to pull apart and try different setups.
 

[Vortex]

Nov 17, 2016 7:40:30 GMT -8 1967gto said:

Thanks Vortex.

Have you tried making the entire core (except maybe the floor) with insulated refractory? I made a rocket stove with refractory and perlite, which works great but is not very durable.

May sound foolish, but what's the difference between low grade refractory and regular refractory?

I haven't tried it yet with just insulating refractory but I intend to when I have my test-bed stove setup. The present design stores a lot of heat in the dense firebox walls that later radiate back into the fire enabling it to gasify the remaining larger fuel. This gives a nice long pleasing ambient fire without any apparent loss of efficiency.

Low grade refractory has a lower maximum temperature range.

[1967gto]

Thanks again Vortex.
My wife and I are in love with the stove you built and want to duplicate. Unless this new idea you are working on is significantly better, than I think we'll stick with the original.
What tipped the scale completely was the ability to open it up for a "traditional fireplace".

[Vortex]

The first few years I only had a solid metal door with no window in it, so I used the stove as an open fire a lot in the evenings, but like any open fireplace it used tons of firewood.

The ability to open it up for a "traditional fireplace" may well be lost after adding a secondary burn chamber above the firebox. I had to play around with the original design of the top of the stove to get it to not smoke when the door was open, and this would undo those changes, so if it's that important for you I'd stick to the original design.

[patamos]

One simple adaptation i would recommend is to cast the top deck (roof of the box with hole for throat) as a separate piece that sits into a nacelle of supports in the side walls.  A solid slab at the current dimensions will give you the predictability of the current application. But will also offer a loose modular fit which will be much easier to cast and will make for a healthy expansion joint to enhance durability and/or repairability.
This piece can be swapped out for a slab of 1.5" ceramic fibreboard any time…. or any other piece as we experiment with new ideas for secondary air flow patterns through the roof and around the throat.
A cast roof slab with air holes coming down from a secondary air plenum will likely only improve the burn
A slab of CFB will likely enhance the full tilt burn, but may reduce the heat retention flywheel in the box enough to alter the slow gassifier mode for the worse.

Aside from adding a catalytic converter above the throat, this slab of roof (and the area around the throat) is where the biggest improvements will likely be happening…  so may as well make it readily replaceable.

[fzurzolo]

Nov 17, 2016 10:30:01 GMT -8 Vortex said:

Hi Pat, I updated the picture to make it a bit clearer what I meant. The secondary air is shown entering between the dense refractory roof of the firebox and the insulating floor of the secondary burn chamber above.
I wonder if the firebox roof was all insulating refractory whether the stove would lose some of it's ability to gasify. I decided for my first test to do half and half and see how that goes.

Drooster, my plan is to make the whole firebox and 'riser section' / 'secondary burn chamber' disassemblable (nope, my computer says it's not a word:)

Something like this, using 1.5" slabs of dense and insulating refractory back to back, (so they equal the 3" thickness of my existing stove walls). It'll all be held together inside a metal framed box like my present setup but complete on all 6 sides and airtight, so there's no need for fireclay between the parts. Should hopefully make it a lot easier to pull apart and try different setups.
 

This thread is great.  Many thanks to Vortex, patamos, et al. for the great info.  I am thrilled about finding this and I will be starting the foundation work for putting one of these in my house (balmy Winnipeg, MB) starting in the new year.  I am a pretty avid baker and was trying to consider how to fit an oven into this design.  I've seen some heaters done by alex chernov where he uses the baking oven as the first bell.  One of the videos out there shows quite a bit of combustion taking place in it and I am wondering if some air leakage around the baking door might be providing the secondary air needed for this.  Given the sketch here, do you think locating the baking oven/bell immediately on top of the unit would be possible? If anybody has experience with this, is there a minimum or maximum size the bell should be for draught purposes?   

[Tom Carty]

I'm thinking of putting a full American style grate with a hob to take the vertices heat and run it through bells.

This stove is very close to that concept.

I need good draught as the house is surrounded by trees taller than the chimney and that's a major problem.

So ability to clean regular is a major part of the plan.

Should I start this design in a separate thread?

Nollaig Shona Dhiabh as we say in Irish Gaelic!