.0001 Micron Dust Collector Filtering...

[Bill Space]

Ha, ha... I suppose it is possible! And I am thinking of doing it!

How? Simply as others have done, send the dust collector air volume outside, and let fresh air come in from the other side of the house.

I may make a small shed roof "room" to hold the dust collector I have, outside the shop. And I will keep the home made chip collector that has proven to be so effective, inside the shop.

Six months out of the year I will lose no thermal efficiency. The other six months I do not spend that much time in the shop doing things that require lots of dust collector time. And on those times I do, well, I will just eat the cost...

Seems like a perfect filter...no need for anything more exotic (and less efficient) than an air mover capable of moving chips and dust from the machines to the outside vent.

A zero micron filter really...unless standing outside by the exhaust vent...which is unlikely here...

Am I mis-guided?

Bill

[Jim Neeley]

Bill,

Nope, not as long as you realize that your shop heating/cooling system (even if 50,000 BTUs or more) will be totally overwhelmed by the makeup air while running the DC and your shop will very rapidly drop (or raise) to near the outside temperature. For the occasional table saw, planer or jointer use it's probably no big thing. If you use your DC on a sanding station and sand for extended periods then it may not be so convenient. :-)

Jim

[david brum]

I switched over to outside exhaust two or three years ago. I don't notice any heat loss while I'm operating the DC ( 3 hp) and my thermometer reading isn't any lower at the beginning of a work session than at the end. My activity and operating machines must make up for it. I do notice a heat loss if I forget to close the blast gates all night, though. It's like leaving a little window open.

I'm very happy with the performance. I hated cleaning filters and always thinking that I wasn't breathing clean air.

Do you have a system worked out for how you'll check to see if your DC bag/barrel is full? Outside venting can create a real mess if the bag overfills.

[David Kumm]

If you have allergies or the outside air isn't great your filters will improve your life. I heat in the winter and air condition in the summer to help with humidity and the shop air is much better than the pollen outside. Dave

[Jim Neeley]

I switched over to outside exhaust two or three years ago. I don't notice any heat loss while I'm operating the DC ( 3 hp) and my thermometer reading isn't any lower at the beginning of a work session than at the end. My activity and operating machines must make up for it. I do notice a heat loss if I forget to close the blast gates all night, though. It's like leaving a little window open.

I'm very happy with the performance. I hated cleaning filters and always thinking that I wasn't breathing clean air.

Do you have a system worked out for how you'll check to see if your DC bag/barrel is full? Outside venting can create a real mess if the bag overfills.

Hmm.. ok, it's just that if a shop was 20'x20'x10h a DC pumping 1,000 CFH would dump the shop air in 4 minutes; 20'x40'x10'h would be 8 minutes. Perhaps you're one of the lucky dawgs with a really large shop or maybe you don't run your DC very long at a time? :-)

As for the mess, is there any chance this is a DAMHIK? <grin>

[david brum]

Hi Jim

This has been discussed quite a bit in the past, so it might be worth looking up some old threads on the subject. As I recall, the consensus was that the large, dense objects like the machines, benches, floor, etc weren't changing temperature and made most of the difference in heat retention. I wouldn't dream of trying to describe how or why that works. Maybe somebody will come along who can explain it. I can only say that my shop is around 55 degrees F most of the time, regardless of how much I'm using the DC.

[Rod Sheridan]

Hi, the issue of heat loss, or infiltration in the summer is a concern, depending upon where you live.

It's true that machines have high thermal mass and will store heat energy, however if it's -25 outside the shop is going to become too cold to work in very quickly.

In summer, I would lose my air conditioned air, and bring hot, water saturated air into my house. The enthalpy of the incoming air would be very high, which my air conditioner now has to take care of.

The cyclone in my shop actually reduces the indoor air particle count lower than the outside air by a factor of 3 to 5................Rod.

[david brum]

That's an important point, Rod. The idea of -25 degree air streaming into my shop makes my shiver to think about. I'd bet that most of us who vent outside live in fairly temperate climates. The OP lives in Pittsburgh, which isn't doesn't have an extreme temp range.

[Rod Sheridan]

Thanks David, I presume that you also have a temperate climate based upon your location.

Regards, Rod.

[david brum]

Yep. It's rarely colder than 25F in winter, more commonly in the 30s-40s. Also not terribly humid in summer either. I don't know anybody locally who has AC in their shop.

[Jeff Duncan]

One thing to keep in mine is even if you dump everything outside, you'll still have dust in your air, it's pretty much inevitable in a wood shop. First off most woodworking equipment is built with dust collection as an ofter thought. The Europeans are out in front on dust collection, (and safety as well), but even if your shop is equipped with brand new top of the line Euro equipment, there's still always going to be some dust that escapes collection. Then you have all the little operations, like drilling, cutting biscuits, etc, etc, that generate smaller amounts of dust. If you buy your lumber rough...there's usually a healthy amount of dust just handling it.

All this to say that blowing air outside will surely help minimize dust to some extent, but you'll still want/need air filtration regardless of how efficient your dust collection is

good luck,
JeffD

[John TenEyck]

I use my 1200 CFM dust collector fan to ventilate (outside) my temporary spray booth. I've sprayed for well over an hour at a time in the dead of Winter when it 10 - 20 F outside, and loose maybe 1 or 2 degrees temp. in my shop. The thermal mass of everything in the shop prevents the temp. from dropping very fast. Same thing in the Summer, the temp. doesn't go up much but the humidity does as evidenced by the dehumidifier kicking on soon after I start start the fan, and it will continue to run until well after I am finished and close the windows again.

John

[Dan Hintz]

I'm trying to imagine how even large thermal masses (block walls, floor slabs, etc.) can transfer heat back into the shop air to prevent dropping the temp. Physically removing the workshop air is a fast process (minutes)... transferring heat from thermal masses to incoming air is a relatively slow process. In my mind, the two equations simply don't match up over the specified time period.

[Joe Hillmann]

I use a 1200 cfm furnace blower to vent my lasers. I often run it for 10-15 hours a day around Christmas with the low temp often being near zero F that time of year. When I run the exhaust I find that the area of the shop where the lasers are becomes several degrees warmer and the temp of the rest of the building drops. After about an hour of running the temp in the laser room starts to drop. That is when the furnace kicks in and then runs pretty much nonstop until a half hour after I shut down the exhaust. I know it adds a lot to my gas bill but I just have to figure it in as a cost of doing business. Also in the summer I will let the blower run all night to get cool night air into the building and then shut it off during the day.

[John McClanahan]

Yep. It's rarely colder than 25F in winter, more commonly in the 30s-40s. Also not terribly humid in summer either. I don't know anybody locally who has AC in their shop.

You are one of the lucky few!

John