It is not my intention to bring up an old topic that can be searched
for and read.
Seconldy, by searching and reading older posts I found William F.
Pentz's wonderful site on <a
href="http://billpentz.com//woodworking/cyclone/index.cfm ">Cyclone Dust
My question is based on where to place the system. I have read about
how air needs to be replaced, a vacume being created and dust seeping
into the house.
I am still in the planing stages of my shop. I have about an 800 sq
foot basement that is pretty empty except for a lawnmower, washer and
My initial thought was to have it placed outside in my backyard area by
punching a hole through the foundation or going through a window, but
then I read about the air needing to be replaced and the vacume being
created. Cost of heat is not an issue as my lungs are more important
One other problem and I think it is larger than any other I will have,
is that my furnance is also in the basement, but frankly that is my
next post with an appropriate topic heading.
On 23 Jan 2005 16:20:59 -0800, firstname.lastname@example.org wrote:
The first question I would have on this matter is the effect of the dust
collector on the draft of the furnace. If the amount of air drawn through the
DC/Cyclone - as much as 800 cfm, if Pentz's recommendations are followed - is
not returned to the shop/basement, will makeup air be pulled through the furnace
flue? I don't know whether or not this is a valid concern, but if you do wind up
with backflow through the furnace you'll have a potentially serious, even
deadly, situation. For that reason, I would lean toward returning the DC exhaust
to the shop/basement through a set of high efficiency filters. That would not
only neutralize any tendency for backflow though the furnace, it would also hold
down the need to heat/cool the makeup air.
If the furnace is in good repair, circulated air does not pass through the
flames. It passes through and absorbs heat from a heat exchanger that is heated
by the flames. The reason for that is to isolate the heated room air from the
combustion products of the oil flame. The heated air goes through the furnace
air ducts into the living spaces. The combustion air and products go up the
furnace flue. You definitely do not want them venting into the living spaces.
Not only do they smell bad, they contain some pretty hazardous fumes. Think
about running an automobile engine inside a closed garage. (Yeah, I know, it's
not exactly the same thing, but it's close enough to give an idea of some of the
dangers involved.) That is why you definitely do not want to have a reverse
draft, or backflow, through the furnace flue.
If you use well designed dust hoods on the woodworking machines and use a DC
system with sufficient airflow to capture the fine particulates at their source,
you shouldn't have a significant problem with airborne dust particles. The idea
is to keep them out of the air in the first place. If they do enter your
breathing air, a standard furnace filter won't do much to help clean them out.
The dust particles that are the main danger are much too fine to be trapped by
the coarse filters using in most furnaces. A separate, circulating air cleaner
will help, but a significant amount of the fines will enter the furnace
circulation system before they pass through the air cleaner.
My recommendation - for whatever it might be worth:
1. Use a high flow rate, efficient cyclone and good dust hoods to collect the
sawdust AND the airborne fines at the source and separate out all the sawdust
and most of the fines.
2. Duct the cyclone exhaust through high efficiency particulate filters to get
the rest of the fines and exhaust the clean air back into the shop/basement to
prevent creating a backflow situation through the furnace flue and firebox.
1a) Get rid our your power tools (and sandpaper) and go completely Neanderthal
with your woodworking.
Good Luck and Happy Woodworking.
Wichita, KS USA
If you have the space for it, make a room or closet for the DC. Instead of
covering the walls with sheetrock, cover large areas with filter media. The
best would be some sort of HEPA filters. You'd want enough area to easily
carry the 800 cfm even after partial blocking from use.
Think distance. Locate your system exhaust as far from the furnace as
possible. Don't pull air through the chimney, re-use it.
A lot of flummery out there about particle size and such won't change
reality - filters which provide multiple paths to open air efficiently trap
the smallest of particles in low flow areas. Then you have your body's
natural defenses, and the inescapable truth that the "danger" of organic
particulates is extrapolated from data on inorganic particulates where
individuals worked every day in virtually opaque atmospheres.
Pleated felt-type filters will do just fine to re-filter your exhaust. It's
a cleanliness issue, not a health issue.
I hope the lawnmower stored in your basement is electric. If it's gasoline
powered health problems caused by sawdust would be a minor concern.
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
On 25 Jan 2005 03:10:46 -0800, email@example.com wrote:
Hmmm, how about recycling some context with those comments?
The absence of accidents does not mean the presence of safety
Army General Richard Cody
On 26 Jan 2005 01:10:58 -0800, firstname.lastname@example.org vaguely proposed
......and in reply I say!:
remove ns from my header address to reply via email
Sorry.. What are you talking about now? <G>
Seriously, it is considered polite to post a bit of the message you
are replying to...but not the whole damn thread every post.
However, AFAIAC, if I am interested in what you are saying enough to
gripe about your "bad behaviour" I can go and see what you were
replying to anyway.
If the dust collector is in the same room as the tool it is working with, no
vacuum will occur in the room itself. The air being drawn in the hose will
be blown out thru the bags.
Just make sure you have the height requirements for whatever unit you intend
You say that now, wait until you get the bill. As long as you use good bags
on you collector, there is no need to move it outside. Moving it to the
outside will cause a vacuum in your basement and it will draw that air from
anywhere it can including the furnace. If you thought that dust was bad,
just imagine carbon monoxide.
If you are concerned about that you can always build a tiny room around it
to protect it and use furnace filters on the door so that it can get the air
it needs. If you have good bags on your dust collector and a good air
filter setup, the furnace will be just fine without doing anything other
than a cleaning once a year (and you should be doing that anyway).
If at first you don't succeed, you're not cut out for skydiving
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