Because he thought it would keep my neighbors happy (and the building inspector happy) our engineer has spec'ed a spark arrestor to go in the powered exhaust system for our four forges. (Not that I expect much in the way of sparks off a coal fire, but there may be times when we want to burn charcoal.)
It's a $1000+ item. The fool thing has no moving parts. It works by disturbing the laminar flow so that the sparks lose their 'insulation', the pocket of warm air around them, and burn out quickly.
We pushed back and suggested that a bit of relatively fine screen at the throat of the forge hood and the fact that the air is passing through a big ol' squirrelcage blower ad the exhaust end should have the same effect, to which the engineer said. "Yeah, that should probably work." Jeeze.
Anyway, anyone have any experience in this department?