There's a host of calculations you need to make to know the proper dimensions/locations of each component. Chucking one together with random sized/located components often kinda works, but not very well. Also, two big issues with a prefilling the primary burn chamber with fuel. 1: The fuel absorbs heat, cooling the chamber, thus resulting in poor vapourisation of the fuel. 2: The fuel gets hotter and shallower, thus more fuel evaporates - resulting in an over-fuel and rancid black smoke. The fuel-air ratio in the primary burn chamber is going to change as the fuel gets shallower/hotter. Drip feeding the fuel helps avoid these problems. It allows the primary chamber to get much hotter and keeps the fuel evaporation at a continuous rate. It needs to work in harmony with fuel-air in the secondary burn chamber. Too little air entering the secondary chamber will mean a harder draw on the primary chamber...More smoke... You've also got a straight pipe acting as secondary chamber/flue. The flames need somewhere to slow down and expand as they leave the primary chamber - or the flames speed up and come out the pipe before they've finished burning. Your pipe needs more holes and the re-burn pipe needs to be higher. Or, the flue pipe need a big chunk chopping off the top.
Your entirely correct. I just threw it together one day for somthing to do. But it's going to end up in the scrap pile and I'm going to buy a nice and proper one.
I've been trying to work out the theory of how one of these things work for ages. Cheers ledge I'll begin to modify my home made one with this stuff on mind
@@simongibbs9392 I wouldn't bother with a return pipe. But if you do, you'll know it's working right when the whole thing is humming like a pulse-jet. However, they work just fine without and don't 'hum'. The return pipe is pulling preheated air down, into the primary burn chamber. Smudge pots were designed to keep orchards warm in winter, out in the freezing cold. The preheated air is to help keep the primary burn going. Otherwise the only air getting into the primary burn chamber would be freezing cold. Thing is, if you're making something similar, it's better and easier to simply insulate the primary burn chamber.
@@brianmurphy8790 rightio. I grabbed some 200 round and 150 galv ducting from the job site today and even found a piece of 75mm and a elbow. I'll tinker in the shed and knock something up to see if I can get one running smoothly with this awesome info. Thanks!
i used to have same issue, it was nice & scary pop gives me adrenaline rush. any how, putting an air damper inside the burn box will prevent that unbalance mixture of air & fuel ratio
Not bad. I'm not sure what the little side flue thing is doing. In many smudge pots they loop inside to catch unburnt fuel and recirculate but yours just appeared to be functioning like a support. Still a nice little burner. Would you have changed anything about it now that you had a chance to test for a while or is it perfect?
@@thomasvaughn8915 I know how they are meant to work. My point was that the way this one was designed I don't see it actually doing its job. It's looking more for aethetics than actual function due to the way he implemented it.
There's a host of calculations you need to make to know the proper dimensions/locations of each component.
Chucking one together with random sized/located components often kinda works, but not very well.
Also, two big issues with a prefilling the primary burn chamber with fuel.
1: The fuel absorbs heat, cooling the chamber, thus resulting in poor vapourisation of the fuel.
2: The fuel gets hotter and shallower, thus more fuel evaporates - resulting in an over-fuel and rancid black smoke. The fuel-air ratio in the primary burn chamber is going to change as the fuel gets shallower/hotter.
Drip feeding the fuel helps avoid these problems. It allows the primary chamber to get much hotter and keeps the fuel evaporation at a continuous rate.
It needs to work in harmony with fuel-air in the secondary burn chamber.
Too little air entering the secondary chamber will mean a harder draw on the primary chamber...More smoke...
You've also got a straight pipe acting as secondary chamber/flue.
The flames need somewhere to slow down and expand as they leave the primary chamber - or the flames speed up and come out the pipe before they've finished burning.
Your pipe needs more holes and the re-burn pipe needs to be higher. Or, the flue pipe need a big chunk chopping off the top.
Your entirely correct. I just threw it together one day for somthing to do. But it's going to end up in the scrap pile and I'm going to buy a nice and proper one.
I've been trying to work out the theory of how one of these things work for ages. Cheers ledge I'll begin to modify my home made one with this stuff on mind
How does the return pipe work. In my mind hot glasses should be pushing up through the smaller return pipe and into the larger flue in my mind
@@simongibbs9392
I wouldn't bother with a return pipe.
But if you do, you'll know it's working right when the whole thing is humming like a pulse-jet.
However, they work just fine without and don't 'hum'.
The return pipe is pulling preheated air down, into the primary burn chamber.
Smudge pots were designed to keep orchards warm in winter, out in the freezing cold. The preheated air is to help keep the primary burn going. Otherwise the only air getting into the primary burn chamber would be freezing cold.
Thing is, if you're making something similar, it's better and easier to simply insulate the primary burn chamber.
@@brianmurphy8790 rightio. I grabbed some 200 round and 150 galv ducting from the job site today and even found a piece of 75mm and a elbow. I'll tinker in the shed and knock something up to see if I can get one running smoothly with this awesome info. Thanks!
i used to have same issue, it was nice & scary pop gives me adrenaline rush.
any how, putting an air damper inside the burn box will prevent that unbalance mixture of air & fuel ratio
I have the same issue. What do you mean by an air damper on the inside. Thanks
Not bad, for a test run!
😊
Not bad. I'm not sure what the little side flue thing is doing. In many smudge pots they loop inside to catch unburnt fuel and recirculate but yours just appeared to be functioning like a support.
Still a nice little burner. Would you have changed anything about it now that you had a chance to test for a while or is it perfect?
It acts like a “Turbo” and is suppose to recycle heat back to the bottom of the pot to increase the burn temp and burn cleaner
@@thomasvaughn8915 I know how they are meant to work. My point was that the way this one was designed I don't see it actually doing its job. It's looking more for aethetics than actual function due to the way he implemented it.
I like your design. What size of pipe did you use?
It's just 4inch chimney flue.
How big is that chimney and what is it or where did u get it ?
It's just a standard length of stainless combustion heater flue.