On Sun, 11 Nov 2007 08:29:04 -0700, "W. Kirk Crawford"
wrote:
I am interested in a dust collection system, 2hp, for my shop.
What I want is when I turn a machine, there might be 12 machines, it turn on the dust collector and stays on 3 or so minutes after I
turn off that machine.
Am I going to have install 'gates'? Or can they also be controlled by the machine?
If you haven't already found it, I'd recommend spending some time on
Bill Pentz's dust collection website,
http://billpentz.com/woodworking/cyclone/index.cfm
Questions have been raised about some of the data and opinions
expressed by Bill on the site, but it remains the most comprehensive
and, IMO, objective discussions on the design and implementation of
dust collection that I've encountered.
Gates:
Yes. If you have 12 machines serviced by the DC, there is no possible
way that a 2HP system will provide sufficient airflow to service 12
machines simultaneously. You'll have to shut of the flow at the unused
machines to have enough flow at the one being used. Gates are
commercially available in all the common duct sizes and they are
fairly simple to build for yourself. Numerous articles and plans for
shop-built blast gates are available. DAGS if you're interested.
There are methods of automatically controlling the gates. One
commercially available system can be found with a Google search on
"EcoGate". You'll have to decide for yourself whether such a feature
is cost effective for your operation.
Don't know the size of your shop, but if you can comfortably fit 12
machines in it, you might want to reconsider the power of your system.
2HP sounds a little small to me. My shop is about 1200 sqft and a 2 HP
blower proved unsatisfactory. I am currently installing a 5HP blower
wheel in my cyclone.
Time Delay:
Can't speak for anyone else, but there is enough rotary inertia in the
motor and blower wheel of my system to keep it spinning and moving air
for more than enough time to clear the ducts after the DC is turned
off. Personally, I'd consider a time delay relay to have an advantage
only if the DC would otherwise be frequently restarted within the time
delay period. IMO, time delayed shutdown is probably more appropriate
in a multi-user/commercial shop.
Tom Veatch
Wichita, KS
USA