Are the Eko, Econo, Tarm, etc as simple as they appear?

[hdivr]

I like the design and how they "gasify" and force everything down through the wood coal bed to completely burn as much of the wood as possible.

I like diy projects and I'm wondering if one could take a used wood furnace similar to Wood Chief, Victor, etc. and remove the lower ash pan clean out. Line entire top and bottom area with refractory and just drill a hole between the two separations and place another plate of refractory to serve as a nozzle. And then force the exhaust to exit from the bottom chamber and through a tubed heat exchanger. It would otherwise be similar to other boilers (aquastats, air injection, pumps) but without all the electronics.

I was thinking of building a seton type boiler with the massive refractory and welding up a similar heat exhanger. But the more I sit and look at the YouTube vids of all the gasifiers, I really like the downdraft design with the intense torch like heat. So I can start from scratch and weld up the two chambers, doors, handle, etc. But after looking at the design, I'm thinking I could just buy a used wood furnace for less than 500 buck off of craigslist. It would save me a bunch of time and welding. So here's some questions.

Has this been tried and rejected because the standard firebox couldn't handle the heat? Or couldn't be make airtight very easily?

Can the Eko, Econo, or Tarm keep a coal bed without the every 6 minute "burst" of air? Or is the downward gasifier dependent upon the electronics.

Thanks for any input.

 

[hoth2oguy]

not strictly dependent on electronics, but remember you have to inject new combustion air into the wood gas as it is injected into the secondary chamber. You would want to start with something that has boiler tubes too, not just a firebox surrounded by water, I think. Could get more complicated than it may first appear....

 

[Nofossil]

They are simple, but that simplicity hides a lot of complexity that goes into the design. There's a range of primary / secondary air ratios that are needed. There's a range of nozzle velocities that you must stay within. There's the materials needed to withstand the temperatures and temperature gradients involved. The primary chamber is pressurized (in most designs) and must be PERFECTLY sealed.

It looks simpler than it is. People have built their own, and some of them work very well. To really nail the design takes a lot of hard-core engineering and/or luck. Best to start by copying a known good design.

 

[Duetech]

hdivr,
Try looking at the Greenwood too. I first found out about gasifiers by seeing one of their ads. They use electronics too but they don't have the forced purge like the EKO,and others, at least not the older versions. The older version, at least used natural draft instead of forced draft to accomplish gasification. I went with the EKO for a number of reasons. Forced draft was one of the positive ones though cost and availability were big factors as well. My thought though is if you are intending to build one you should at least look at a natural draft version to satisfy your questions about options.