Length of the 'neck' of the oven.

[newaqua]

Hello everyone.

Just wanting to know if there are any special requirements that need to be considered when building the front 'neck' of the oven which has the chimney and front facade on it.

I was thinking in the case of the fire drawing properly when burning.

Any ideas?

[Les]

Re: Length of the 'neck' of the oven.

Actually you want to keep it as short as possible. It makes it easier to reach into the oven.

[Gulf]

Re: Length of the 'neck' of the oven.

Les is probably right on this advice. His advice is just about the consensus on entries. I have not worked a shallow entry so I don't really know what "easy" is. Mine is quite deep, but I am able to work it without too much effort. That is with the short time that I have been cooking. I do have zero smoke issues, even at start up. In a few more months I should be able to recommend or, not recommend a deep entry.

[Tscarborough]

Re: Length of the 'neck' of the oven.

The oven will draw just fine with no chimney, so the question is one of making it large enough to not impede the natural flow. The neck, per standard design constraints is to keep the angle at less than 45 degrees in the throat and smoke chamber, make the flue at least 15% of the area of the door, and maintain the 62-63% for the door VS oven height.

[cnegrelli]

Is there a definition of the "neck" somewhere?
i've got a 32" dome, 16" high, 10" door opening, 20" wide.
I plan to have entry area about 12" deep, from the bottom of dome at the entry width.

Is this in line with design suggestions?

[cnegrelli]

Re: Length of the 'neck' of the oven.

The oven will draw just fine with no chimney, so the question is one of making it large enough to not impede the natural flow. The neck, per standard design constraints is to keep the angle at less than 45 degrees in the throat and smoke chamber, make the flue at least 15% of the area of the door, and maintain the 62-63% for the door VS oven height.

I'm unsure of terminology such as neck, throat and smoke chamber and the precise definition of flue. Is throat the same as gallery/entry? Is it referring to the opening of the dome itself? Is neck the same as throat? By smoke chamber, what is meant?

Most of the door openings I see are arched. Is the 63% figure from floor to peak of that arch? How is width a factor and how to determine optimum width?
I also don't understand the "flue at least 15% of the area of the door".. Do you mean the area of the chimney opening, or by Flue, do you mean the sloped area below that?

[shanxk8]

Curious about this as well, perhaps someone could quickly sketch out something illustrating the features described by Tscarborough with the recommended ratios?

[JRPizza]

You both are posting on a 4 year old thread
Some of the threads here can get confusing with folks using different terms (like brick taper and bevel). I'd highly suggest figuring out how big you think you want your ovens to be (I see cnegrelli wants a 32") and doing a search to locate a few well documented builds of the same size. If you do you can see where they are similar and different which will kind of show you what your options might be. You would also do well with a set of the formerly free FB pompeii oven plans, which you can get from the store for a nominal cost
That said, chimney pipe or tile comes in some standard sizes. I think it is recommended to have an 8" round (or similar area) for a 40"+ oven (that is what I used for my 39") and a 6 inch round for 32" to 36" oven. If you are working with brick (as opposed to casting) for your vent, lots of folks make the depth 1 and a half brick (around 13.5") as that seems to be a good size for building up the brick arches and transition from the width at the floor to the opening for the chimney. If you use metal pipe there will be a mounting plate, and you just have to make an opening that has enough area to feed the cross sectional area of the pipe. Some will say a slight constriction is OK, but I just made a wide transition to help the flow of hot gasses up the flue. Think aerodynamics.
The 63% is to the top of the arch whether it is flat or curved. Your outer arches will be a little taller to provide a reveal to seal your door against. Good build threads will help you understand this. I made liberal use of Gulf and Utahbeehiver's threads, but there are so many good ones to learn from. I tried to document mine to fill in some of the things I had to learn by asking questions, so you might want to have a look at it also.
Sorry about the rambling reply - feel free to ask lots of questions!

[shanxk8]

JR, thank you for the reply. The suggestions are great, not rambling at all. I will lookup the posts from Gulf, Utahbeehiver, and yourself.