Silo Gazebo - Smoke Problem

[CobyRupert]

It’s the air moving over the top of a chimney that improves draft. Just get it up away from the roof.
If you don’t want to extend the chimney up, extend it down. Like in ski lodges where pipe comes down and then splays into a circular hood just above the fire.

 

[KennyG]

Just use an induced draft fan for a furnance;
Induced Draft Furnace Blower, 115 Volt: Replacement Household Furnace Motors: Amazon.com: Tools & Home Improvement

Not sure this would work. I think it's a fan for a high efficiency furnace. Wouldn't work for this application.

 

[metalbender]

A heat duct booster fan at the outer dia of the gazebo, with a pipe following the roof line to the stack, blowing up inducing a draft.

 

[MossRoad]

That might work.

I'd concentrate on building the smokeless fire pit, first though.

 

[etpm]

It seems to me that not much air flow through the hole in top is needed. Why not try a little experiment? If you have fan available, even one with plastic blades, you could lay it across the hole. If the fan is too small then lay a couple sticks across the hole and lay the fan across the sticks. Build a fire, wait for the smoke, then turn on the fan to see what kind of a difference it makes. I think this might help you evaluate how big of fan you might need. If you have one of those non contact hand held IR thermometers then you could aim it at the fan blades if you turn off the fan or maybe the fan hub while it's running to get an idea of just how hot the fan gets. It may be that the smoke will be cool enough to not cause a problem. Anyway, just pulling an idea from my butt, so it may be no good. On the other hand (the one I didn't use to pull the idea out) if you have the fan, sticks, and thermometer on hand, so to speak, this experiment will only cost you time.
Cheers,
Eric

 

[etpm]

That might work.

I'd concentrate on building the smokeless fire pit, first though.

A smokeless pit, while better because of the more efficient combustion, will still behave the same way, having the combustion products in the same place as the smoke. While less irritating everyone will still be breathing burning wood exhaust. But the exhaust should be hotter and maybe it would be hot enough to start the draft working properly. Now, wouldn't that be cool. Or hot.
Eric

 

[jmc]

OP's pic is not clear but that roof hole may be mostly capped, leaving just a perimeter vent around the hole. I think Elvis had left the building by the time I asked about it.

 

[NormL]

OP's pic is not clear but that roof hole may be mostly capped, leaving just a perimeter vent around the hole. I think Elvis had left the building by the time I asked about it.

OP disappeared after posting his question/problem! Probably figured something out himself and moved on.

 

[Gord Baker]

Open the Manway in the roof to help air flow. Use seasoned wood. Double up on the refreshments.

 

[Kschwennsen]

To build a chimney but not have it show would be to have a hood vent that comes down over the fire pit with the stack inside the silo to the vented peak. I think that would look good, produce plenty of upward draft.

 

[Little Red Tractor]

I'd talk to someone who builds fireplaces for a living. They generally understand the dynamics of draft better than the rest of us. Also, using dry hardwood is a big help. The punky stuff that most of burn in bonfires don't do well is open fires.

 

[Handloader109]

Vent cover in top is way too low. Need 6 to 8 inches gap. if it is wide open, it would vent, IF the fire is big enough. That is the other issue, small fire would not carry heat high enough unless it is really cold.

 

[NCAlaskan]

Wow...lots of good ideas here.
The top hole is wide open to the stars.
I tried a box fan on the top and it seemed to help in round one.
I am also working toward the smokeless idea and looking for a quiet exhaust or inline fan that can handle some heat.

 

[NormL]

Wow...lots of good ideas here.
The top hole is wide open to the stars.
I tried a box fan on the top and it seemed to help in round one.
I am also working toward the smokeless idea and looking for a quiet exhaust or inline fan that can handle some heat.

When the smoke is hovering under the roof without exiting the two foot(?) hole I have to wonder just how hot is it anymore and is it really an issue for a fan, be it a box fan or a ceiling fan. Before rejecting those two options, NCAlaskan, I suggest hanging a wireless temperature sensor from the opening to get the real-time proof. My guess is that the smoke has cooled significantly due to proximity to the metal roof material which is exposed to cooler air on the outside. Granted, Once the smoke is forced to exit via the opening, the smoke temperature will not cool quite as much since it is not spending the time hovering, but it will still cool due to the lack of a confining effect of a flue such as a stove pipe or chimney. Just my 2cents + tax

 

[Don1958]

open the manhole cover as well also put holes along the top of the wall steel to vent the smoke

 

[DGZRT]

Simple build a gas fire place . I took a wood burning pit with a table around it . Got it at Menards for 70$ I had a Turkey fryer I never used . Took the big burner out of the fryer and placed it in the bottom of the pan then laid Lava rock around the burner and cheap ceramic logs I found on clearance. I had to add a small cover over the air inlet and adjust it so it went from blue flame to blazing fire . This took me all of an hour to build and a 20# tank last for about 30 hours or more . No smoke and you can just turn it off put cover on and not worry about it . If the 8” burner out of the fryer is too small for you buy a gas fireplace burner off EBay

 

[NCAlaskan]

Update:
Test one: Father-in-law built me a smokeless firepit that works smokeless. That helps and dry wood helps but the problem remains. A little smoke and you are hacking smoke.
Test two: [Now to try your other ideas...]

 

[Egon]

As mentioned, a cupola.

Or, a fan set up with an inductor. Fan blows ambient temperature air.

Instead of the air starved fire pit build up a platform for the fire to sit on. Makes for better air flow and ambiance.

Somewhere, in the deep recesses of the mind, I recall something about “coreolis effect” Which might be happening with the design in question. Central core of rotating rising air that spreads at the roof forming an exterior core of descending rotating air that follows the walls downward. ??? Well above my pay grade!

 

[ovrszd]

First I would say, Indians didn't have chimneys.....

My Binzebo has similar lid system. On mine the lid can be fastened tightly shut or fastened in a vent position to allow stored grain to vent without letting in moisture. Mine is fastened in the vent position. We've never had an open pit fire but we've used a wood burning "stove" a few times. No smoke problem at all.

In your case, the top lid is not venting at all.

I don't have any closeup pics of my lid and the weather sucks right now so not going to go get any.

 

[HawkinsHollow]

I do like the looks of those binzeebos. Pretty cool if you can get your hands on a cheap/free grain bin.