Black ripple

I extend an invitation to folks in the US to build the BLACK RIPPLE kiln.  Plans attached for FREE.

Contact me on kobus@vuthisa.com for any questions.

https://biocharkilns.com/2023/01/07/introducing-the-new-low-cost-portable-black-ripple-biochar-kiln/





This video shows a similar design. The difference is that we want to reduce wear and tear on the inside of the kiln as well as guide hot insulated air against the 55 gal drum and maximize heat transfer. The rocket stove will result in less fuel required.

Good luck and keep in touch.

Cheers

Kobus

Hello Kobas. Have you built and tried out the design?

I'd be interested to see pictures of a few items you fired in this. Thanks for the free design.

Hi Joylynn,

No problem - the more people that build it the more we can get traction on it.  I have a long history of using rocket stoves in my projects.




We have had Casey build one in Florida - it worked okay but the 55 gal retort took 3 hours to heat up. Ee advised him to enlarge the rocket stove diameter and insulate the inside of the kiln.  You don't need two layers of steel - just a steel ring with insulation on the inside.

Previous discussion with Casey:

"The sooner the process turns exothermic (heat evolved) and opposed endothermic (heat absorbed) and starts producing its own heat the better. So yes if the heat introduced is taking 3 hours to heat the retort - that is too long. One of Winiarski's principles on page 12 (attached) says it is important to maintain the cross sectional area of the inlet to the outlet to ensure a good draft. I used this online calculator https://amesweb.info/section/cross-sectional-area-calculator.aspx to guestimate your cross sectional area. He applied ity to cookstoves but the same thermodynamics apply. "


"Rocket stove INLET: I assumed opening to be 6" by 8" (feel free to enter the correct numbers in the calculator above).  Cross sectional area is therefore 48 ^2" (48 sq inches)

Kiln OUTLET: 40" inner ring and usually a 55 gal drum is 23.6". Cross sectional area is therefore 819 ^2"

This is a pretty big mismatch and one would think that a larger cross sectional area at the outlet would create more draft but it does not aid the  velocity. Channeling the hot rising air past the retort will increase heat transfer if you can increase the velocity. You can narrow the gap by leaving an air gap of around 1.5" only. So you can afford to add between 1" and perhaps 3" max of insulation. It does not have to match the 48" sq inch cross sectional area exactly as there are a lot of other factors at play but obviously OUTLET should not be less than that. I would use kaowool and add a rigidiser or use refractory plaster and paint as shown in this video (forge). I've used chicken wire myself to keep rockwool in place - held in place with flat metal srips runing vertically up along the perimeter with bolts going through the insulation and bolted to the inner panel. Best to do drilling work on the inner panel before it starts oxidizing. Or use ideas from this vid:

https://youtu.be/vk0ZH2cAZUc?si=_cX5ZLsI6HcxzMsU "

Regards

Kobus