Oiled Coal problem

Pacowy wrote:It sounds like it goes back to the oil on the coal near the fire reaching its smoke point, and the draft being insufficient to pull that smoke to the exhaust.
Mike

That is what I belive is happening. not that the draft is insufficient, but the draft can not get to where the oil gasses are on a hopper stove.

My hopper is set in, so there is a small clearance around it but not near enough. I surmise what my buddy did to his by drilling a bunch of holes around the hopper just below the the load door, allows the draft to act upon the hopper better.


One question, on the hitzer is the hopper welded in?



Eric

I'm mostly speculating, but here goes: From fastcat's pictures, the hopper cover must be cooler than inside the hopper, so the oil vaporizes then condenses on the cool hopper cover. Then it runs along the underside of the cover, and the gasket serves as a wick to draw the oil out where it runs down onto the top of the stove. The oil is now completely outside the hopper, sitting on the stove top. Then when you crank up the heat, the oil sitting on the stove top burns and/or evaporates and that's why you smell it.

So if you could somehow prevent the oil from reaching the wick -- the hopper gasket -- it should stay inside the hopper and not cause a problem. I don't know how you would do that. You need something like the drip edge at the edge of your roof to stop the oil and make it drip back into the hopper. A bead of high-temperature silicone all around the top and a quarter inch inward from the gasket, maybe? Or does the hopper cover get so hot that the silicone would break down? A bead of epoxy? -- but that's not good for temps higher than silicone.

Look at FF hopper lid it has the rim 'O metal..
inside of the gasket...
FastCat has no rim just flat...
I'll go with rberq's thoughts on oil leakage...
Plus the hinge can cause an uneven compression of the gasket...
see the side away from the hinge looks oily...

My DS has a hopper and the acidic steam from damp santa coal will peel sheets of rust off the underside of the hopper lid...
My hopper has large vents at the top of the hopper...
I think the lid iscooler and the steam hits it and condenses...

Coalfire wrote:I surmise what my buddy did to his by drilling a bunch of holes around the hopper just below the the load door, allows the draft to act upon the hopper better.

I wonder about that. Seems like the inside and outside of the hopper, all inside the stove, would be at the same absolute pressure, so no vacuum on either side of the holes. Is it possible that convection currents inside the hopper would cause a flow of gases from the inside of the hopper through the holes to the outside, carrying the oil fumes out through the holes and thereby keeping them in the business part of the stove?

And IF that is so, would drilling holes also carry the coal gases out of the hopper near the top of the stove, so they would go up the chimney without burning?

CapeCoaler wrote:My DS ... hopper has large vents at the top of the hopper ...

Vents like the holes that Eric wants to drill? There goes my theory on the inappropriate venting of coal gases.

CapeCoaler wrote:Look at FF hopper lid it has the rim 'O metal..
inside of the gasket...
FastCat has no rim just flat...
I'll go with rberq's thoughts on oil leakage...
Plus the hinge can cause an uneven compression of the gasket...
see the side away from the hinge looks oily...

My DS has a hopper and the acidic steam from damp santa coal will peel sheets of rust off the underside of the hopper lid...
My hopper has large vents at the top of the hopper...
I think the lid iscooler and the steam hits it and condenses...

So you are saying is there are holes at the top of your hopper from the factory and the fire does not burn up into the hopper, Am I understanding this right? If so what size holes should be drilled and how many would you drill and would that be on the front and back or on all four sides?

Now I gotta get the camera...
Where is it...
In the car...
I feel a BK run commin' up...
The hopper drops in and due to the angle has a friction fit...
I can see red coal on 3 sides and there is a large notch for the locking bar...
Notch must be 1.5"x .75" so there is a lot of vent space in the top of the hopper...
Not an issue with the fire creeping up the hopper...
The coal will burn up below the hopper causing the coal in the hopper to move down...
the hopper will be empty before the ash prevents the fire from being high enough to cause any problem...
When I do keep a thick ash bed to keep a low fire with Pea coal Spring and Fall...
I have a small 12"-14" ball buring right at the base of the hopper...
If a fire was ever in a position to crawl up the hopper that would be the time...
The ash under 10" plus the coal over 12" keeps it from burning in the hopper...
Even if it did burn in the hopper, it is still inside the stove...
Unlike a stoker where the hopper is outside the stove...
I will take the pictures...
BK is callin' me...

rberq wrote:
And IF that is so, would drilling holes also carry the coal gases out of the hopper near the top of the stove, so they would go up the chimney without burning?

CapeCoaler wrote:My DS ... hopper has large vents at the top of the hopper ...

Vents like the holes that Eric wants to drill? There goes my theory on the inappropriate venting of coal gases.

Rberg, I think the smoke point of oil is much lower then the off gas point of coal (if I am wrong someone will correct me ), It is doubtful that you will lose gases from the coal without being burned.


Capecoaler, my stove has those same vents. look at the second pic down
Pictures of your stove it is tough to see but you can tell since the hopper is a drop in there is a little space around it, and the smaller notch where the latch goes.

However the way I seen this smoke come out you could tell it was under pressure, so I belive that little space is not large enough, hence the need for holes. That would probably vary by how much oil is on the coal.

It would be interesting to see a pic of your stove

Eric