Roeland's catenary shaped brick oven.

[Peterrr]

Attached is a picture of my catenary shaped brick oven project.
Hearth slab size is 90 cm x 84 cm (5 cm thick).
Wall thickness is 10 cm.
Vermiculite bottom insulation is 10 cm.
To keep thermal mass low, allowing short/fuel efficient heat up
times, I will add no cladding.
Will post more pics as builing progresses...

[jengineer]

Not a traditional high mass bread oven but a definite twist to the pompeii

load up more pics.

[dmun]

That's neat! We keep hearing about the structural benefits of the cantenary, and we look forward to cooking reports. I hope there's insulation under there somewhere...

[n2iko]

Only thing is needs is a way to neck it down to gain a throat for a chimney.
The shape is very pleasing to the eye.

--mr.jim

[Peterrr]

@dmun: I have 4 inches (10 cm) of vermiculite insulation under there.
@n2iko: I was planning to make the front/chimney side a straight wall
(like the back side).
Do you think it is necessary to "neck it down" ?

[dmun]

Some kind of flue funnel will help with the draw. You don't want smoke in your face (and smoke stains on the front of your enclosure) when you are fueling the fire at the beginning.

[n2iko]

It is my experience that a nice even flow of gases increases efficiency. The doorway vent area is a very important to this flow. It is the seperation point of the incandescent gasses. Makes the chimney a bit quieter also.
Your call at this point.


--mr.jim

[CanuckJim]

Peterrr,

This is solely based on my experience with different types and shapes of ovens, including round and barrel vault. If you do not neck down to a vent/flue area, what you will have in essence is a fireplace, not an oven. You really want the combustion air to come in at floor level and the combustion gasses to exit at dome level. Without narrowing the vent area, you will not create the necessary venturi effect for efficient combustion and maximum heat output. You really want the intake/exhaust cycle to speed up as much as possible for a bright, efficient burn. Without that, you'll be burning a lot of wood to create the same amount of heat. It's a saying on this forum that you can never have too much insulation. The exterior of your dome should be insulated to the max you have space for. The whole idea is create the heat as efficiently as possible, then retain it for as long as possible.

Jim

[Peterrr]

Plan is indeed to put a thick insulation layer on the oven.
2" ceramic blanket + 2" vemiculite concrete.
I will post some more pics later of the vent/flue contruction I intend
to construct.
Here some more clarifiying (I hope..) pics:

[Peterrr]

At last, I decided on how to close the front.
Also this weekend the provisional setup for the chimney was made.
I wanted to "test drive" the system to see if it works before starting to insulate it.

It worked out really good!
No smoke escapes, draw is very good.

Here are the pics: