Re: Digest Number 221

Steve Gunsel wrote:

> the systems automatically close a damper (quickly) to isolate the
> dust collector or inert with Halon or whatever to prevent an
> explosion. At least the commercial ops that have had a "big one".
> Definitely gets your attention.

Worked in a sheetmetal shop, during it's early growing days they had
some antique belt grainer and were using a wood dust collector on it.
The large filter bag accumulated a nice big lump of aluminum dust by the
time someone came along and tried to grain some steel.
That was a better explosion than anything I ever did in my younger days!
Even better was the 10lbs or so of smouldering aluminum power that got
deposited on the overhead platform. Despite my warnings, the idiot boss
tried to hit it with a C02 extinguisher. The resulting fireballs were
really impressive. (he was a slow learner, took three such flare ups to
convince him I was right)
After that the shop built a water trap filter with blow-off safety
panels. Combustable dust under the right conditions can demolish a
building (as with grain silos) and is not something to mess around with.
(except for fun, of course...)

Jon