Dust Collection in University Shop Questions

[Jack Carliton]

I teach sculpture and welding to university students and recently moved to a new institution. The facilities had been neglected over time and I am in the process of revamping the dust collection.

Currently there is a 800 cfm 2HP AFF shaker type collector inside the shop. I am having this moved outside since it just blows fine dust out the duct. That should help a lot. It has a 6" inlet that drops immediately down to 4" and continues as 4" for the rest of the system. The woodshop is approximately 20' x 80'.

I do not have any budget to replace the collector. I do not have budget to improve any of the piping. I may get to make the main run 6" though. Currently there are a lot of 90's and other bends. It has a copper wire in it for static electricity.

If you had to deal with improving a semi large shop with and existing but outdated dust collection system, where would you concentrate your efforts? Are there any other educators out there that have had success?

I appreciate any and all advice.

[Philip Rodriquez]

In your case, I would bring in a pro to take look at it. Look under "air handling" in you area.

[Dan Hintz]

It immediately drops to 4" with lots of bends? I doubt very much dust collection is going on in that shop, especially one that size. If they don't give you money to improve the system, there's not a lot you can really do... you need bigger ducting, and a beefier collector for that big of a shop wouldn't hurt considering you'll be running multiple machines at once.

[Jim Beachler]

If all you do is make the main trunk to 6", then do that. It will help some and that is better than nothing.
If you have no budget, maybe you can cruise Craigslist to find a couple of bargains. Or talk with some local woodshops to see if they would donate any of their old equipment. Doesn't hurt to ask.

[Jack Carliton]

Thank you for the responses. It turns out that I was able to locate and source a new cyclone from Standard Tools and Equipment with a 7.5 HP motor and a blower that has a 2975 cfm rating. The inlet is 10". I also was able to secure approx $1200 worth of budget for ducting. This is good news but I want to get this right because it will not be changed for a long time. Do I run 6" pipe to each of the tools? Since it has a 10" opening do I try to go with 10" ducting for as long as possible? Should I try to locate the machine outside for noise and fine dust removal? What system do people use to empty the metal 55 gal barrels of sawdust?

Thank you again for the help, have been a lurker here for awhile.

[Jeff Bartley]

Jack,
Just in case you haven't it; google Bill Pentz, his research and writings has got to be the most extensive I've ever seen. There is formulas for everything involved (cfm, ductwork size, length run, etc).
As for emptying the barrel: mine's just bungie corded onto the bottom of the cyclone.
Good luck! And if you haven't yet considered it I'd suggest putting that big cyclone in a closet, I bet it howls!
Jeff

[Jim Neeley]

Jack,

One big consideration here in Alaska that may not apply to you is that placing the DC outside will have you pumping 2975 cfm of warm (or cool, in hot climates) air out of the shop. This air must be made up somehow and heated or cooled by the building HVAC system or open windows, doors, etc.

Hopefully the building (or complex) is big enough that 3,000 cfm won't disrupt the air flow or make the temperature unbearable. A good question for your maintenance personnel.

That much air being pulled out of my 25' x 25' x 10' garage shop would mean the heating system would have to replace the room air every two minutes.

[Kevin Groenke]

Hello Jack,

I manage a shop in a design school and have struggled with air quality over the years. (pretty good now after a big renovation) If your institution has a health and safety department they may be able to help with design and/or funding improvements. Of course they can also complicate matters if the shop has been "under their radar" for some time, so that is worth consideration. If there are significant health and safety concerns, they may be able to motivate your department to find the money ( ie "fix it or close it").

From the description of your shop and my assumptions re: nature of work and equipment, it sounds like the machine you have is simply not adequate for the task.

There is an on-line community of higher-ed shop personnel... check your PMs for the link.

best,
kg

[Jim Neeley]

Kevin,

Why do you say a 7.5hp, 2975 cfm DC with a 10" inlet is not adequate for the task? Intuitively it sounded to be a reasonable ROM size to me...????

Jim