Forno Bravo Forum: The Wood-Fired Oven Community

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-   Design Styles, Chimneys and Finish (http://www.fornobravo.com/forum/f9/)
-   -   Smoke Venting (http://www.fornobravo.com/forum/f9/smoke-venting-2562.html)

Dotan 09-14-2007 03:51 AM

Smoke Venting
 
Hi all,

I have built a wood fired oven for baking bread.
I have problem with the smoke venting, if someone knows about the physics of fire and smoke in baking ovens, I can use a good advise.
where to put the chimney? how do I manage to get the smoke out of the oven ond not losin a great a mount of heat? Is it depend on the type of wood I am using?

I can post some photos if you like me to,
and if you don't have a clue about the smoke venting physics, then maybe you know a web site where I can get instructions and answers.

Thanks, and Shana Tova.

Dotan.

Bacterium 09-14-2007 04:14 AM

Re: Smoke Venting
 
Hi Dotan.......and welcome to the forum. Good to hear you already have an oven and bake bread. Hope you find the forum useful it contains a very wide range of aspects on wood fired ovens.

Would be good to see some pics of your oven and the area surrounding it. The are a whole range of factors with how you can control your air from the oven, however this will help us understand what your situation is.

Some of the basic things to start with are:
-Size/Shape of oven(internal)
-Is the oven inside a building or external?
-What sort of wood is used?
-What existing doors/vents/flue/chimney does your oven have etc.?

Dotan 09-14-2007 04:51 AM

Re: Smoke Venting
 
1 Attachment(s)
Ok, Mate

So here it goes:

I going to add a link to my album (it is hebrew...), sorry.

Picasa Web Albums - Dotan - ב*יית ת*ור האדמה

I'm attaching a sketch I made so you could see the size of the oven.
I built an earth oven. It is placed outside, the chimney is 2m high, the doors are iron made...

Any information I haven't given yet?
I can translate the Album if nessecery...

Dotan.

dmun 09-14-2007 05:20 AM

Re: Smoke Venting
 
An oven with the fire below the baking chamber is called a "white" oven, as opposed to the pizza oven that has the fire directly in the baking chamber. Do you vent the smoke through the baking area, or do have a separate vent in the firebox?

For some information on this type of oven, you might do a web search for "masonry heater" which incorporates a white oven and a lower firebox.

Dotan 09-14-2007 06:12 AM

Re: Smoke Venting
 
I use a chimney which is placed at the upper part of the baking area.
Should I replace it? I posted a draw so you can see the place of the chimney.

Dotan 09-14-2007 06:33 AM

Re: Smoke Venting
 
I searched the web a little bit about information about "white" ovens and masonry heater, but I havn't found information about ovens I can cook in, just ovens that are meant to heat the house.

does someone have information about baking ovens that are white ovens
or...
does someone have an advise I can use about reducing the smoke in the cooking chamber?

Thanks for the posts, people!
I am glad I found this forum.
Dotan.

maver 09-14-2007 07:08 AM

Re: Smoke Venting
 
Dotan, some of your issues may be about basics of combustion - I shared some thoughts on this in your Chimney installation post - maybe that helps?

Marc

Dotan 09-14-2007 09:30 AM

Re: Smoke Venting
 
Yeah, I read your post about chimney installation. Thanks a lot.
I will search for more white oven issues, though I having a bit of a hard time finding information about those white ovens.
If you have any like (person or a website) that could help - Then I'll double my thanks to you! :-)

Dotan.

mheat 09-14-2007 11:47 AM

Re: Smoke Venting
 
Hi Dohan:

I'm not quite clear from your photos what the gas path in your oven is. It looks like there is a bottom firebox, with a throat at the back that runs past two hearth slabs, and then out through a stovepipe at the top of the upper chamber.

Here is a drawing of a traditional commercial Finnish bake oven, which has two chambers, with the fire in the lower chamber. It is a black oven, ie., you bake after the fire is out, and the flames go right through the chambers:

heatkit.com/graphics/pbakeo1.gif

Here is another oven with the firebox below the baking chamber, also with the flames routed through the chamber:

heatkit.com/docs/ov-fr01.gif

that is a traditional French commercial oven. The picture is not too good.

In a white oven, the flames don't go through the baking chamber. Instead, they go around the outside, such as in the Spanish Llopis revoving hearth oven:
jllopis.com/IPSORE3.htm

On your oven, if I understand it correctly, you might want to open up the throat a bit at the back to the first baking chamber, and change the upper one so that the gases have to go to the front before they enter the upper chamber.

Also, you may want to control the air supply to the fire by reducing the opening.

Best ...... Norbert Senf

Dotan 09-17-2007 01:45 AM

Re: Smoke Venting
 
Well, my oven has three chambers: one for fire - the lowest, the second - for baking and also the third. As you can see in the drawing I added the previous post, the whole three chambers are actually a big one space, which is divided by trays for baking the bread on them. the trays are "standing in mid-air" so the heat can pass through to the top. Once the fire is on - the WHOLE oven is heated.

I placed the chimney on the top of the oven, and I was given advice that perhaps I should install the chimney aside the firebox, hopefully the smoke will come out of there and the oven will still be heated. but then, I lose a lot of heat, don't I?

Take a look at my pictures at picase web albums, it might help.

(Picasa Web Albums - Dotan - ב*יית ת*ור האדמה)

Greetings to all of you who'd answer and took a moment of their time helping me.
Dotan.


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