Thein baffle on shop vac???

[JDuke]

I have thein top hat under a HF DC and am pretty happy with the separation.

I also have a shop vac mounted on a stand with dust deputy over a 5 gallon bucket, but that thing is a space hog.

I recently bought a metal 35g barrel to store fish food in and noticed that the shop vac suction assembly fits the barrel well.

I got to thinking about cutting a tangential port for 2.5" hose in the barrel and making a thein baffle to go under the shop vac filter.

I haven't done this yet because I'm concerned that the shop vac suction will interfere with good cyclonic air flow.

As I understand for optimal air flow the inlet for the blower should extend down the middle of the top hat, and the shop vac filter would be in the chamber off center.

I'm wondering if this decrease in effect would be worth the effort or if the force of air from the tangential intake would be enough to force most of the dust to outer perimeter of the can and leave the filter fairly clean.

Of course the big benefit would be the whole thing would just take up the floor space of a shop vac and be taller.

Duke

[Phil Thien]

The outlet doesn't need to be perfectly centered, offset is fine.  You just don't want it to get too close to the edge where all the debris is swirling.

[Patsfan]

The outlet doesn't need to be perfectly centered, offset is fine.  You just don't want it to get too close to the edge where all the debris is swirling.

And what would you know about a Thien Baffle

[Lynden]

I thought the outlet opening had to be a certain distance below the bottom of the lid. Will air entering through the sides of the filter affect the performance?

[Phil Thien]

I thought the outlet opening had to be a certain distance below the bottom of the lid. Will air entering through the sides of the filter affect the performance?

The filter will likely collect more debris than if it was external to the separator.  How much more is difficult to say.  It will function substantially better than a conventional shopvac, though.

[clydeone]

The simple answer is yes - you want to keep the debris closely adhered to the wall of the separator and anything you do to move the suction closer to the wall (i.e. drawing in through the sides of a typical shop vac filter) will decrease the separation performance. How much - that is a question to be answered via some high level modeling or better empirical data.

Edit - sorry Phil I see you beat me to the answer.

[JDuke]

I guess I'll give it a shot then.

Thank you for all the information.

Duke

[Phil Thien]

The simple answer is yes - you want to keep the debris closely adhered to the wall of the separator and anything you do to move the suction closer to the wall (i.e. drawing in through the sides of a typical shop vac filter) will decrease the separation performance.  How much - that is a question to be answered via some high level modeling or better empirical data.

Edit - sorry Phil I see you beat me to the answer.

No this has turned into a community effort, I'm always happy to see others helping.

[bennybmn]

I tried it once, and had minimal success. My theory at the time was that the diameter of my vac, and thus the separator, was too large for the velocity and volume of air my vac was moving, so it didn't force the debris out of the stream well. This is not negative commentary on Phil and his design, I have a baffle in my DC and love it! I just don't think I was executing it well. So I bit the bullet and got a dust deputy. But I mounted it in a frame between the vac head and tub. You can see I made a chamber for the (hepa) filter from bent lexan, and capped the stock hose inlet. I also didn't want to take up any more floor space.

Only thing is it can be a little tippy, because, as we know, shop vac's can't even roll over their own cord without stopping!

Added bonus: it can actually hold 12 gallons of debris.

[JDuke]

Tried it anyway and my results agree with benny.

Didn't work very well

Shop vac sucked well and the coarse dust got past the baffle, but the filter clogged quickly with fine dust that it pulled out of stream to early.

Then I tried a small plastic bucket over the filter with the bottom cut out it didn't help much, probably because the bottom of bucket and filter inside was to close to top of baffle,

Thanks
Duke