Pre stage for ash vac

[GaryS]

Looking at setting up an ash vac system for my father/mother in law in their fire place. Been searching here and looking around and don't really see any vacs that says it's OK for hot coals. I was thinking of using a sealed metal barrel inline between the stove and the vac to hold the majority of debris between the fireplace and ash vac. My shop dust filter uses the same premise. That way, any hot coals accidentally sucked up would stay in the inline barrel.

They have a pretty neat custom made system. the fireplace has a large firebox that has a door in the back so it can be fired from the unfinished side of the basement. The front has glass doors facing the living room. The whole ash aparatus can sit in the room behind fireplace.

 

[blades]

The problem with any type of vac system lies in in the particulate filter system. All I have seen are flammable, therefore dangerous to use with live coals present. Even in a 2 stage system there still exists the possibility of migration of hot embers in the air stream to flammable filter materials. A system with an extremely fine primary metallic filter ( this would involve multiple layers of wire mesh of a diameter to resist heat) and the then much further down stream a particulate filter of the hepia variety could possibly be built. Still a certain risk factor will be inherent because nothing can be made that is 100% reliable in a dry air stream system.

 

[LLigetfa]

The problem with any type of vac system lies in in the particulate filter system. All I have seen are flammable, therefore dangerous to use with live coals present...

I think the filters on vacs made specifically for ashes are probably not flammable. As for fine particulate, getting through or clogging the filter is is the problem.

I had an idea to design a closed loop system where the exhaust returns back to the intake. It would use a double hose, one inside the other. The inner one would be suction and the outer one, the return. This of course would be based on the premise that enough flue draft was maintained so as to draw up the airborne ashes that would get stirred up.

Another idea was to have two hoses where the exhaust could be directed up the flue. If you had a lazy or reversing draft, it would not work so well.