Re-thinking dust collection... a 'new' way to do it?

[REK Knives]

I have never wanted to vent air outside because my shop is heated and cooled... and in order to do that you have to have some way for fresh outside air to come in your shop, which wouldn't be heated or cooled without a heat exchanger (from what I've been told)

So I though I was reduced to getting a traditional filter set up. But I was talking with my FIL and he had a good point... what if you had a supply line (from outside, fresh air) and an exhaust line (the blower end, that would pump air out of your shop). You would then position 2 hoses at each station... a fresh air hose and an exhaust air hose. This way the air that is not climate controlled would only be traveling a short distance and not heating/cooling your entire shop.

This would eliminate the need for a large footprint for a traditional filter, and it would also lower costs significantly.

Has anyone actually done it in this way? Does this work? and if so, how well does it work? I know a lot of guys suck the air out of their shop but their shop isn't heated or cooled.

 

[Edwardshandmadeknives]

I have never wanted to vent air outside because my shop is heated and cooled... and in order to do that you have to have some way for fresh outside air to come in your shop, which wouldn't be heated or cooled without a heat exchanger (from what I've been told)

So I though I was reduced to getting a traditional filter set up. But I was talking with my FIL and he had a good point... what if you had a supply line (from outside, fresh air) and an exhaust line (the blower end, that would pump air out of your shop). You would then position 2 hoses at each station... a fresh air hose and an exhaust air hose. This way the air that is not climate controlled would only be traveling a short distance and not heating/cooling your entire shop.

This would eliminate the need for a large footprint for a traditional filter, and it would also lower costs significantly.

Has anyone actually done it in this way? Does this work? and if so, how well does it work? I know a lot of guys suck the air out of their shop but their shop isn't heated or cooled.

I’ve never thought of that, but it looks like a pretty good idea.

 

[MTBob]

After wrestling with this problem for years, I abandoned the idea of pulling outside air into my shop that is located in a cold climate. So, I use a self contained localized dust pickup at the grinder that picks up dust/grit at the point source and can serve as a whole-shop air filter.
The idea of creating a "flow through" approach to dust pickup as shown may seem to be a good idea in theory. But, I'm doubtful that it would be all that effective. First, the flow in should match the flow out and that would be tricky to accomplish. The "spillage" of cold air into the shop combined with pulling warm air from the shop - even IF a matching flow through pattern could be achieved - I think would be very inefficient.
And this all gets way more complicated when you add specialty jigs to the grinder OR flip the grinder into a horizontal mode.
If you figure out how to do this I would really like to see how it works.

 

[REK Knives]

After wrestling with this problem for years, I abandoned the idea of pulling outside air into my shop that is located in a cold climate. So, I use a self contained localized dust pickup at the grinder that picks up dust/grit at the point source and can serve as a whole-shop air filter.
The idea of creating a "flow through" approach to dust pickup as shown may seem to be a good idea in theory. But, I'm doubtful that it would be all that effective. First, the flow in should match the flow out and that would be tricky to accomplish. The "spillage" of cold air into the shop combined with pulling warm air from the shop - even IF a matching flow through pattern could be achieved - I think would be very inefficient.
And this all gets way more complicated when you add specialty jigs to the grinder OR flip the grinder into a horizontal mode.
If you figure out how to do this I would really like to see how it works.

Thanks for chiming in Bob!

As far as matching the air flow I would use the same ID size duct for both sides and only have 1 port open at a time to the blower.

The supply side (at the grinder) would be as close as possible to the exhaust duct but even if it's a foot or two away it should work in theory because the air pressure in my shop would be negative, it would be a lower pressure than the outside air that is coming through the supply duct (positive pressure). So the exhaust would naturally want to draw air from the easiest source (ie higher pressure source) and *should* draw only from the supply outside air.

But I do wonder on really cold days if this would make my shop temp drop... I do live in SC which has more mild weather than other areas of the country but it can get into the teens or 20's sometimes.

I wonder if an inline duct heater would be possible for the incoming air...

 

[Coop]

Check out air to air heat exchangers. I built a super insulated house. Vapor tight. I use a air to air heat exchanger to bring it climate controlled air in my house. Lots of folks make residential size units now days. It brings fresh air in, using it as it closely passes over stale air transferring heat or cooling to temperate the fresh air. Most commercial buildings or schools have air to air heat exchangers to bring in fresh air without loosing energy from heating or cooling. Think sick buildings.

Most old school thinking was a house needs to "breath" to let fresh air in. Thinking you could build a building to air tight to be unhealthy. Me personally I'd rather bring in controlled fresh air in conditioned rather than leaving a window wide open all year long or worse yet building a poorly insulated house intentionally to let fresh air in.