On 16 Nov 2004 04:49:40 -0800, (mnterpfan) vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Rant on. HTH.

One thing to remember. A good cyclone will stop a heck of a lot. In
fact I saw where the 'standard" bags on a DC are a waste of time if
you have a good cyclone!

........but.....and a big but...there are really fine bits (5 micron
and below) that get through.........and the standard bags are "not
needed" because they do not stop exactly these fine bits! It's being
found that these fine bits are what really damages your lungs. So if
you have a good cyclone (or not!), then you need proper filters on the
outlet, not the bags that come with the DCs. Probably the ideal is
cyclone, bags, then fine filter. Cyclone stops the bits, bag stops a
bit more, last filter stops the real nasties. Each one is easier to
"clean" than the next one. Final filter may not be cleanable at all.

There are filters called HEPA. High Efficiency Particulate Arrestance.
Some filters are _called_ HEPA. Others _are_ HEPA, AFAICS. These are
medical grade. "Boy in a bubble" stuff.

However, I have been advised that you do not really need HEPA filters
for shop use. They are often expensive, small in area (less time
before they need replacing as they clog), and often not reusable.
There are industrial filters, that go down to .5 micron particle size,
that are "concertinaed" to give huge area, and are a lot cheaper than
HEPA per "cub ft of stopped dust", so to speak. Check with an
industrial filter supply. That's where I went, and the guy was quite
helpful. He could have sold me HEPA at twice the price, but was
advising what he thought were better solutions for the real world.

Also remember that any filter system will need maintenance, and to be
kept free-flowing. A lot of people say that bag filters increase in
effectivness as they clog up, because the dust stuck in the weave acts
as a better filter. But of course this results in reduced flow, so you
lose a lot of the effect.

Rant off

I recently purchased a Torit Cyclone Dust Collector. I already have a
brand new Jet 2HP filter canister type dust collector. The cyclone was
not too terribly much more expensive than one of those plastic garbage
can cyclone separators and trash can. It looks to be in very good
condition with one small dent. Plus, it has the cabinet at the bottom.
Therefore, no need for a 55 gallon drum and stand.

A quote on the Torit site about cyclones states: "Can be used alone,
with filter bag assembly, or as a pre-cleaner."

Can someone please explain the pre-cleaner setup? The picture in my
mind is of the cyclone exhaust being fed into a second DC intake. It
seems like almost nothing should make it through, but who knows? Is
this at all feasible? Am I completely misunderstanding the term
pre-cleaner.

I have heard of using other blower fans as boosters. I have the same
picture in my mind about that setup and have the same questions.

Any help would be appreciated.

Thanks,

Eric