Height of Chimney intake point

[thijsatteiltje]

Hi guys,

I am considering if and where I should place my chimney. I have drawn two diagrams to illustrate.

I'm building a simple clay oven and some of these are without chimney and just vent through the door. But I would prefer to have a chimney and already have a nice piece of stainless steel for that purpose.

Now, I have just build a solid stone door arch (no dome yet)

I wanted to keep the construction simple because building the chimney opening inside the door arch seemed to complicated for me.

The door arch is 27cm high (10.5") and I was planning to make that 63% of the dome height. (as I said ,the dome has not been build yet)

I would like to place the chimney directly behind the door arch but that raises the following question:

Do I
A: Leaf the opening of the pipe horizontal and place it on the recommended 63%?
The problem with this is that it would leave a small on top of the dome where smoke would gather, would it find it's way out the chimney?

Or:
B: Cut the chimney pipe to follow the shape of the dome but thereby having the back of the stove pipe opening be higher than 63%

(see diagramgs)

The (planned) measurement of the oven are:

Door opening 47cm x 27cm (18.5" x 10.5")
(this has already been build)

Dome: 80cm x 43cm high (31.5" x 17" high)
Chimney diameter: 15cm( 6")

Cheers,

Matt

[david s]

It is better to have the chimney in front of the oven door. Also it works better if you have an inverted funnel leading to the bottom of the pipe to make a good flow to gather the smoke.

[thijsatteiltje]

Originally Posted by david s

It is better to have the chimney in front of the oven door. Also it works better if you have an inverted funnel leading to the bottom of the pipe to make a good flow to gather the smoke.

With "In front of the oven door" you mean have the hole for the chimney be part of the door arch? Yes,I know, but i was not confident I would be able to build this.

With "inverted funnel" you mean to have the walls and sides around the chimney opening slade towards the chimney opening to 'guide' the gasses?

Matt

[david s]

chimney opening slade towards the chimney

Matt[/QUOTE]

????

I think you need to have a look at the Forno Bravo plans, or at least look at lots of pictures on various threads.

The second two ovens I built had their flue openings in a similar position to your drawings. They worked OK, but nowhere near as well as a flue that is in front, and independent, of the oven itself.With your configuration you"ll get too much heat loss and every time you open the oven door cool air will rush into the oven and hot air will exit the flue. If you do it this way you need to arrange a baffle in the flue so it can be closed. This is all extra work and only does half a job .The flue outside the oven is superior IMO.

[thijsatteiltje]

Originally Posted by david s

chimney opening slade towards the chimney

I think you need to have a look at the Forno Bravo plans, or at least look at lots of pictures on various threads.

Sorry, help me out here. English is not my first language and I was trying (badly) to clarify what you were trying to say.

I have read through this forum an do realize what the Forno Bravo plans look like, but I am using the directions used for earth ovens. (like this one: Earth Oven Progress Update | Wild Yeast )

And I realize I'm trying to add a chimney at the wrong moment of the project.

So, looking at the two pictures I posted, would you suggest to keep the 63% height and change the dome's shape/size/position to make a better funnel for the smoke?

Cheers,

matt

[brickie in oz]

Go with the second pic, mine is similar and works just fine.

[thijsatteiltje]

Originally Posted by brickie in oz

Go with the second pic, mine is similar and works just fine.

Thanks Brickie,

putting the grinder to the metal in 3...2...1... If it all goes to s* i'm swimming over the ditch to give you a firm talking to! ;-)

Matt

[brickie in oz]

Dont forget, like David said, you will need a chimney damper to retain the heat.

See my build.