Return-Stack orchard heater - smudge pot/choofa

[B-Man]

Not really a drip system but a non pressured one.

Anyone running one of these with no smoke?

How does the return pipe work?
Do you limit the amount of air intake in the base so it has to suck it through the holes in the first part of the flue and then through the return pipe. Meaning any smoke etc is sucked back down into the burn zone by the return pipe causing it to burn very clean?

[Fly]

I don’t understand what that down pipe unless it is causing more draw. I wish someone could explain?

     Fly

[Oilburner]

I have wondered about the purpose of that pipe myself.
I cannot figure out what it is suppose to do.