Gases are no longer necessary! MULTI-FUEL BURNER pipe for heating.

 Gases are no longer necessary! MULTI-FUEL BURNER pipe for heating.

This is a model that I made inspired by several finds made on the net. I am not a stove builder so this is only done by guesswork and after some reflections. I do not hold myself responsible in the event of an incident. Have your construction validated by professionals in the event of risky use (domestic).

Regarding the construction, certain dimensions are adaptable according to the resources available (size of cans, glass, mold, etc.). On the other hand, there are still rules to respect. For example, the surface area of ​​the inlets and outlets. I made a choice to have an inlet with a smaller section than the outlet (80 * 100 mm = 8000 mm ^ 2 against Pi * R ^ 2 = 12271 mm ^ 2) which prevents fumes from rising because they always go where the diameter is larger. It is necessary to make adjustments on the reduction of the conduit at the end of the combustion chamber because if the reduced section is too small, the fire will be smothered, which can cause the fumes to rise. But a minimum reduction is necessary to induce the vortex. Question of adjustments :)

The refractory concrete must have a minimum thickness of 30 mm (40 mm is better) otherwise it will crack. Refractory concrete can be purchased in most DIY stores but you can make your own dosages with molten cement, vermiculite (found in stores) and chamotte (a type of crushed brick which is the aggregate, but more difficult to find).

The horizontal wood supply must be as inclined as possible to allow the branches to descend, but its height must be much lower than the internal chimney (about twice) otherwise the height difference is not sufficient for the fumes to be sucked up by the internal chimney. The shape of the air and wood inlets are rectangular because it is easier to recover the ashes and generally I find it more practical.

The vitroceramic hob brings heat quickly into the home, which is pleasant to feel when it is cold and you want to heat the room quickly. But to keep a little more heat after the fire is out, you can put an insulating cover to keep the heat in the mass.

As for the weight of the mass, the more there is, the more slowly the heat will be redistributed. Personally, I had a weight limit due to the construction of the dome on stilts. But the 200 L cans are not bad because you can have a more spacious bell (optimized transfer of calories) and a more substantial mass. My small stove weighs about 150 kg, which is already quite a bit. I did some thermodynamic calculations to estimate the duration of heat re-emitted and I calculated about 7 hours so it seems to work. I can find the calculations again when I have time. But the more mass there is, the more spacious the room can be or the longer the heating time. The distance between the top of the internal chimney and the ceramic hob is important because too far away, the hob will not heat up enough to cook on it and too close, the gases will not have enough room to escape. The surface area of ​​the internal chimney must be equal to its perimeter multiplied by the necessary height. Generally speaking, you have to make sure that all the sections have the same surface area after combustion and that the gases do not see their output reduced. It may not be very clear said like that, but to put it simply, a gas will not like to pass through a smaller diameter. You can start from a slightly smaller input to go to a slightly larger output (as I was able to do and improve the draw) but the opposite is not possible.

In short, I recommend reading the forums and sites mentioned because there is a whole science behind it and it is absolutely fascinating. The sites that particularly helped me are Peter van den Berg's on the Batch box and the practical guide of Poelito which gives lots of tips (although the surface dimensions are not optimized).

 Gases are no longer necessary! MULTI-FUEL BURNER pipe for heating.

This is a model that I made inspired by several finds made on the net. I am not a stove builder so this is only done by guesswork and after some reflections. I do not hold myself responsible in the event of an incident. Have your construction validated by professionals in the event of risky use (domestic).

Regarding the construction, certain dimensions are adaptable according to the resources available (size of cans, glass, mold, etc.). On the other hand, there are still rules to respect. For example, the surface area of ​​the inlets and outlets. I made a choice to have an inlet with a smaller section than the outlet (80 * 100 mm = 8000 mm ^ 2 against Pi * R ^ 2 = 12271 mm ^ 2) which prevents fumes from rising because they always go where the diameter is larger. It is necessary to make adjustments on the reduction of the conduit at the end of the combustion chamber because if the reduced section is too small, the fire will be smothered, which can cause the fumes to rise. But a minimum reduction is necessary to induce the vortex. Question of adjustments :)

The refractory concrete must have a minimum thickness of 30 mm (40 mm is better) otherwise it will crack. Refractory concrete can be purchased in most DIY stores but you can make your own dosages with molten cement, vermiculite (found in stores) and chamotte (a type of crushed brick which is the aggregate, but more difficult to find).

The horizontal wood supply must be as inclined as possible to allow the branches to descend, but its height must be much lower than the internal chimney (about twice) otherwise the height difference is not sufficient for the fumes to be sucked up by the internal chimney. The shape of the air and wood inlets are rectangular because it is easier to recover the ashes and generally I find it more practical.

The vitroceramic hob brings heat quickly into the home, which is pleasant to feel when it is cold and you want to heat the room quickly. But to keep a little more heat after the fire is out, you can put an insulating cover to keep the heat in the mass.

As for the weight of the mass, the more there is, the more slowly the heat will be redistributed. Personally, I had a weight limit due to the construction of the dome on stilts. But the 200 L cans are not bad because you can have a more spacious bell (optimized transfer of calories) and a more substantial mass. My small stove weighs about 150 kg, which is already quite a bit. I did some thermodynamic calculations to estimate the duration of heat re-emitted and I calculated about 7 hours so it seems to work. I can find the calculations again when I have time. But the more mass there is, the more spacious the room can be or the longer the heating time. The distance between the top of the internal chimney and the ceramic hob is important because too far away, the hob will not heat up enough to cook on it and too close, the gases will not have enough room to escape. The surface area of ​​the internal chimney must be equal to its perimeter multiplied by the necessary height. Generally speaking, you have to make sure that all the sections have the same surface area after combustion and that the gases do not see their output reduced. It may not be very clear said like that, but to put it simply, a gas will not like to pass through a smaller diameter. You can start from a slightly smaller input to go to a slightly larger output (as I was able to do and improve the draw) but the opposite is not possible.

In short, I recommend reading the forums and sites mentioned because there is a whole science behind it and it is absolutely fascinating. The sites that particularly helped me are Peter van den Berg's on the Batch box and the practical guide of Poelito which gives lots of tips (although the surface dimensions are not optimized).