rocket pizza oven - V stove dimension

Hi
First of all, thanks to the host of that forum. I greatly appreciate the space for such forum. I think its fantastic that knowledge and interest can comes together.

As the title says, I’m I looking for information and experience for my project.

My girlfriend wanted to have a pizza-oven in their holiday house so they got a used pizza-oven. And it’s going to be my job to put it up.
However, I somehow cannot keep things simple and that’s why I came up with the idea about combining a rocket stove with the pizza-oven. I’ve been playing enough with BBQ and grills to know that one of the worst thing is, not having enough fresh air in the fire.
To give you an idea about how its going to look, the oven itself made of prefabricated fireclay and I thought to put it on to a concrete foundation.
The concrete foundation sits on soil and the front is an old concrete retaining wall. (sorry for bad photoshoping ), hope you get the idea through the picture:




I thought of a concrete foundation with space for the heat to go underneath the fireclay floor where the pizza is being backed on. It would create groves into the concrete like that:



On the concrete foundation comes the fireclay floor of the oven:

A rectangular hole because I think it’s going to be easier cut out instead of a round one.


Coming to the rocket stove:
I thought of digging a V-stove underneath the oven.V because self-feeding would be great (as it will take a while to heat up the oven).
But somehow I will have the get the ash out, so my idea was to make an air-intake as well. The air-intake is seen on the first picture, it comes through the retaining wall.  

I came up with the following idea:
A: as the fuel magazine which is going to be closed with a lid
B: as the heat riser that goes through the concrete foundation into the oven
C: the air-intake through which I will be able the get the ash out of the stove.




In terms of the materials of the pipes, one idea was to weld it together made of stainless steel, not sure thought if it will withstand the heat of the fire over time, so 2nd idea was to insert a fireclay pipe into heat riser (B). The fireclay will certainly withstand the heat better than the stainless steel only.

Just a few dimensions are given till now, such as the length of the air-intake, as the distance between concrete retaining wall to the middle of the heat riser (shown in the foundation picture) which is 73.5cm
And if used, I can only get the fireclay pipes in 120 or 150 mm inner diameter.


If anybody has wondered about the bulky head to the pizza-oven, here is a cross-section of the oven.

the smoke has to travel to the front of the oven, goes then up into the "bulky head". The chimney is at the back of the oven.



Now, I would be grateful for advice from the experienced members.
Will that design work over all?
If yes, what dimension must I have for the pipes?
Thanks a lot,
Michael

Sorry to say, it's overly complicated, with too many restrictions, an angled feed, secondary air missplaced. May be underpowered too.

Do a bit more research ans comme back with a better plan may be.

can you lead me into a direction? i've already spent hours researching but have been unable to lay hands on dimensions of self-feeding set-ups
the circumstances of the oven, the place were it has to sit, that the stove will be underground and the fact that I want to keep the hole in the retaining wall as small as possible might not help, agreed.

what would you focus on, a J or V stove?

Michael, i have spent years researching now.

Don't be put off yet!

Are you familiar with bells? http://www.stove.ru/index.php?lng=1&rs=16

Batch rockets? http://batchrocket.eu/en/

Do you want a pure pizza oven, or more accumulation?

I built a rocket fired oven a few years ago (round dome shape, not rectangular, but more or less comparable in size), and while it works fine, the firebox would probably need to be larger for a good pizza oven. I have an L shaped combustion chamber, about 180mm x 220mm x 700mm long overall horizontal, and 150mm diameter x about 600mm tall overall vertical, which splits below the oven floor and has five openings to the edges of the oven space. The chimney goes straight up from the front.

The size of the wood feed allows plenty of wood, and it is not a burden to keep burning while the oven heats up. To make mine a pizza oven, I would increase the horizontal to say 200mm x 250mm, and the vertical to 200mm diameter.

I think you will have better results with an L feed, as the angled feed will probably be hard to start the draft, and an angled feed does not work as well as a vertical feed for self-feeding.

Give up the idea of any metal inside the combustion chamber, as it will not last. The fireclay pipes you describe are probably not big enough for the heat output you need, based on my experience, and might not last in the fast intense heat environment anyway. Firebricks, or cob, will be durable enough to last for many years. I built my combustion chamber of cob, with firebricks near the front at wear points for better durability. Sacrificial wooden forms made the interior shape of the firebox, and burned out in the first fire.

Glenn that is one cool looking stove! Bread from the heart of the dragon.

Going one step back, do you guys actually think it’s worth going for the trouble of building rocket stove to heat a pizza oven? Or should I stick to the traditional way and burn the wood in the oven itself?

Ok, the view about self-feeding systems are overall not that good. Thanks for the info, kind of doesn’t surprise me, in theory it looks good but fails in real live…
Initially, I wanted to keep the hole in the retaining wall as small as possible, but it seems that there isn’t much of a choice than an L-feed / batchbox and therefore a bigger hole in the wall.
@satamax, its going to be mainly used as a pizza oven and with the rest heat maybe some bread.

Did some research and reading about batchboxes now, did overlook them in my first attempt. The Petersberg-batch-box dimension thread seems to be a working systems, what would you say if I’d stick to those dimensions? Certainly, a good option for me, right?

@ Glenn, so you do have made tunnels underneath the backing floor? You wouldn’t have any pictures before putting the backing “floor” in? How much space have you left below the backing floor? How big are the “tunnels” and the openings to the baking chamber?
Would you do the same heat-channel design again? Do think it helps the baking? Or stick to the easy version and have the vertical tube just come into the baking chamber?

Steel is the wrong material, thanks for confirming that. I’ve been talking to a guy tough, who makes fireclay products and was told that fireclay will not like being buried underground, with all the moisture and even some frost and then been fired up to very high temperatures. How do you see that?
That worries me a bit, as the whole project is a bit of a one chance only, as its going to be a pain to change anything after dug into the ground.
Fireclay riser thickness: are you saying that the 20mm thickness of the tubes will not be enough? Or that the diameter will be too small?
What would you guys say, if I’d go for the 150mm dimensions from Peterbergs’s table? Glenn, you would even go for a 200mm?
150 or 200mm, both ask for a much longer heat riser tube than I can put in, below the oven. I only got about 80cm. How do you see the missing height?
@ Glenn, what temperatures do you reach with your current setup?

Michael.

I have modified a sketchup drawing, to make a pocket rocket pizza oven. It needs a door. But i think this is the simplest type of pizza oven i can do, which should be smokeless or nearly and which isn't overly complicated. It works on the bell principle somewhat. When the door is on. You might need a second tube over the door, reaching the chimney, to capture the gases when the door is open. I would insulate the feed tube, chimney, for better draft, and make a pad of insulating firebrick under the feed tube, instead of hard brick.

looks good!. But doesnt work for me, as I want to work with what I have. And i've got a metal hood that goes over the hole firebrick parts to protect it from rain

Now, it's time to use your brain!

so, I'm getting out of this thread here. As it didnt yield the result that I hoped for.

if anybody is still interested in information about a pizza oven, the following thread has "collected" more information:
http://donkey32.proboards.com/thread/2257/show-rocket-pizza-oven?page=1

Cool ovens
 This one works good....can maintain 350 degree temp.