I thought it would be good to have a dedicated topic to illustrate the How, for-Who, and Why any individual Wood Gasfier design element selected IS actually A CHOICE.
Ain’t no actual Laws to this.
Just general Principals.
Operating Principles. Principals of Practicality. Principals of limitations of current materials and fabrication techniques and abilities.
I will give just one example to get this started.
With a grate.
Without a grate.
Both work; and can be made workable.
Ha! Where do you want to spend your operational time, eh?
Occasionally servicing the below and above grate areas? WHY the factory Imberts distinctively had their three largish round external maintenance ports. To allow for this ashes/soots and fine char clogging maintenances. Pretty Practical solution to a ALL-Must-Flow-Through grate system.
Or CHOOSE to go Grateless.
Then system drawn velocity Must sweep all ash/stoots/fine chars out of the gasifier hearth to be externally separted out from the produced fuel gasses. Some seem to like having to downstream design for this. Then have to Maintnece slave all of that downstream elaborations. Not me.
Grateless makes you a slave to always having the internal system velocity to keep things from Not clogging up.
Right there you chose to have a gas-flow range limitation.
Chose to have a system slaved to the design narrow range of wood base ash percentage.
Me? Use a gasses BY-Pass grating system. A Command active moveable grating system. Retain as much as possible the wood released carbons in the active heating zones for highest percentage of to-gas conversion.
Ash is actually the remaining mineral core of the trees built up carbon chains. So ash in the hearth botton tells me success for my goal.
I want maximum engine driving fuel gases.
I am not a charcoal maker. My low carbons Doug Fir woods, always too wet, even if just from air humidifies, will not support handleably/storable charcoal making. Different climate. Different woods, and I would design Choose differently.
Above the grate clogging on my preferred center post supported Active grate system??
Shake it down. Over the grate edges spilling. Port scrape out, and remove. Manually separate out. Re-cycle, Re-Use the portions. Fused Ash found? Dramatically change Operation expectations. Operating too hot.
No dictated Laws. No you-must’s Always. No Pope dictates this. No Master dictates this. No Genius/Guru dictates this.
Results are your Guide.