Gagan Bansal

Awesome! It's very creative idea.

Some time I can use this idea of beautifying my cob rocket stove using broken tiles.

Thank you Glenn for valuable input.

Gerry Parent wrote:Have you noticed that most of the ash gets blown up into the exhaust stream as your burning?

In total I had done around 30-40 min burning, total ash had not blown up. I'll try next time for longer duration.

Glenn Herbert wrote:The more straw/grass/organic material is in the cob, the more tiny voids there will be and the better insulating.

I got your point. I have used local clay and rice husk with proportion around 2 part clay and 1 par part husk (volume wise). The final cob after adding water and mixing was quite heavy. Next time I am thinking to increase the husk proportion. Any idea what should be the ideal proportion?

Graham Chiu wrote:You need refractory materials for your core. Cob will eventually crack and that will further lower your temperatures.

My objective is to make rocket stove for villagers who are already using three wall wood stove made up of cob. Refractory material would be quite costly.

I have to improve my cob rocket stove only, as I am in learning phase.

Cob wall of riser are 3 inches thick, hope that's quite a good insulation.

Thank you @Graham and @Glenn for your feedback and discussion. I learned a lot with this about the inflow of air in burn chamber.

I was thinking of Bernoulli's principle, consider Figure 1 where stick are at left of feeder (away from burner), as the air after burning from stick is hotter and moving towards riser, the pressures reduce on the left of burning sticks and now opening is on the left so fresh air would be sucked in automatically. And that may help in better burning.

Regarding P channel (thanks @Glenn for dimensions) I have to see how to design in cob rocket stove while casting.

Thank you @GerryParent for your feedback. Regarding the ash after long duration burn, now I have one doubt on my question itself. If the burning is efficient then the ash content should be very minimal. I think my burning of wood was not efficient and that resulted in unburnt wood (looks like tiny pieces of coal and ash). Any comment on this.  

Hi,

First of all thank you for this forum. I learned a lot about Rocket Stove concept here.

I have created a Cob Rocket Stove of 4" system (Dia of pipe).
With ratio formula 1:2:4, dimensions are 6'' feeder, 12" burner and 24" riser.
 



This was my second attempt and overall it worked well. I could see the temperature more than 500 deg C at riser end.



I have one or two questions regarding the feeding.



How much fuel should be fed in feeder at a time for good efficiency? Can we fill it full so that there is no empty space left? I think some empty space is required to suck the fresh air inside.
And if some empty space is required then at what side? I mean in feeder hole, wood sticks should be kept near right edge (Figure 1) or left edge (Figure 2)?

Figure 1 - sticks left side of feeder(x - wall, S- stick)
                      x        x
                      x        x
                      x        x
                      x        x
                      x        x
    SS             x        x
  xSS   x         x        x
  xSS   x         x        x
  xSS   x x x x x        x
  xSS                        x
  x x x x x x x x x x x x


Figure 2 - sticks right side in feeder (x - wall, S- stick)
                         x        x
                         x        x
                         x        x
                         x        x
                         x        x
         SS           x        x
  x     SS x         x        x
  x     SS x         x        x
  x     SS x x x x x        x
  x     SS                      x
  x x x x x x x x x x x x x

Another question is how to run stove for longer duration, how to keep on feeding without blocking (by ash) the burner area? Or what is proper procedure and precaution for continues feeding?

Thanks,
Gagan