Would be very grateful for people's perspectives on my oven design. Have a look at my blog site rocketbarreloven.wordpress.com
Great idea. My own aversion to the barrel oven is that it is too big but that is for my needs. Your blog mentions you particularly liked the bigger size.
I looked at some of the barrel ovens out there and you are right, they are just a fire under a barrel. Just for reference sake, a barrel oven (at least the ones I have seen) is what is known as a "white oven". That is the flue gas does not enter or go through the oven chamber itself. This is as compared to a black oven like the wood fired bread and pizza ovens. Just so you know what I mean by white or black. Here is an example of a rocket fired black oven. (watch the top video) It is of course much smaller than what you are interested in, but it does show one of the design principles you should consider. The rocket stove is a spot heater, note how they used a heat spreader for more even heating of the oven, both right above the flame as well as the oven exit. I don't think the upper one would be of concern to you as the barrel would do much of that work. But I think a rocket below the barrel would burn through the barrel wall sooner than it should without a flame spreader over the rocket. Also, a rocket burner would tend to heat one end of the barrel or the other, or just the centre. Maybe a spreader shaped like a long upside down trough (upside down "U" extruded) might work. Using two rocket heaters would mean the portion of the barrel inside the building would be increased and awkward to run.
It comes to my mind there is a rocket powered barrel oven in one of the Aprovecho (is that spelled right?) publications, they use a "J" tube rocket and the barrel is set upright instead of laid down on the side. It is sort of a barrel inside a barrel kind of device and the door gives access to a number of round shelves inside. They have used it for making bread, but I don't know if it is a good pizza oven. Here are some links to "Capturing Heat". The first one has the oven I mention above, the second one has lots of detail about spreading heat in rocket fired stoves that may help too.
There is another rocket fired bake oven I have seen that is square. The cooking area is 48x48 in. and can be single or double high. This one requires welding and brick work and is probably more than you want. I mention it because they show some interesting methods of heat spreading. Rocket bake oven manual
48in square seems to be the limit as for bigger installations they use two or four separate ovens.
Your design will be different from all of these. Post pictures as you go and results. Don't be afraid to share also the parts that didn't work and what you do to fix them. It looks like it will work well for you.
posted 5 years ago
Hi there! Many thanks for the quick and elaborate reply. It is very helpful to read through some different ideas. Had not come across the term white / black oven before.
Take a look through the different pages, as am now onto my second bake in the later pages.
The heat seems to spread surprisingly evenly across the barrel, I think because the chimney and riser are not aligned and the "barrel within a barrel" approach provides a heat spreader (the barrel element page) I shall have to see just how long things will last with the outer barrel dispersing the heat in this way...
Thank you so much for the interest and perspective.
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