J. Phil Thien's Projects

Hi,
I built a dust collector with a thien baffle a few years ago, using a 3 hp blower with a 160 mm hoses and pipes.

Until now, the blower blows the air outdoors. This has worked well, but cools the workshop down quite a lot in the winter.

I am moving this summer, and will have neighbors too close to just let it blow outdoors in my new workshop (because of the noise - it sounds like a jet engine). So, I'm looking at adding some filters to let the air back into the workshop.

My first thought was to make two rectangular drawers, one with a coarse filter, and one with a hepa filter. This feels like a great setup, as I can just pull out the drawers and clean them outdoors. However, I've started wondering if these filters will let enough air through. Maybe this would remove too much suction power from the dust collector.

Would a hepa cartridge filter be better? Like this one:
https://www.axminstertools.com/hepa-filter-for-t-2000ck-2hp-cyclone-505090

That one seems to be designed for a 2 hp blower. Maybe it would be too small for my 3 hp blower?

I'm attaching a drawing of the version with two filter drawers. It's a see-through version, so the walls around the output are not visible.

I'm planning on building a top hat Thien baffle. The only thing I have not decided yet is whether to build a double top hat or a "normal" top hat separator.

I'm going to use 6" ducting throughout  my system. I will probably use the 44 gallon Brute trashcan (or perhaps the 32 gallon one).

So, the diameter of the baffle is either 24" or 21.9" (not sure if that's the inside or outside diameter of the trashcan).
I'm making a transition (in sheet metal) to go from 6" to 8" x 3.5". This means the minimum internal height of my baffle will be 8".

So, the internal height for a double height baffle would be 16" (2H of square duct), or 12" (2H of 6" round duct). Not sure how I should count.

I will vent outside. So I'm not after 99.9% separation. I'd rather get more CFM's than perfect separation, as the small amount of dust that makes it through the separator, will blow away in the wind, once outside.

Does the 2H top hat promise better separation or better throughput? I've been reading loads of threads, but I'm still not sure if I should go for the 2H build or not.