Square sided lower container?

[drum365]

I'm planning to build a top-hat separator, and I'm wondering what effect the shape of the lower cabinet - the space below the baffle - has on efficiency. What I'm considering is building a standard, side-inlet, cylindrical top hat, and putting it on top of a simple plywood box - roughly a cube, maybe 2' on a side.

Most separators seem to be built on barrels or drums or other cylindrical shapes with the same diameter as the separator. Is this important? I read about "decoupling" the air flow between the separator and the lower portion and wonder why wouldn't  a larger, rectangular box be better at that than a cylinder? It seems to me that in a same-sized cylinder, you end up with a complementary vortex (albeit, at a slower speed) in the lower portion. What happens if the chips fall below the baffle into a larger, flat-sided container? It seems to my clueless, newbie way of thinking, that this would be desirable.

Has anyone tried this? I admit I'm totally new to this whole concept and probably missing something. Thanks for any input! (And thanks to Phil for sharing such a great concept!)

[alan m]

it shouldnt cause any problems. and like you think it might help.

try it and report back

[phil (admin)]

it shouldnt cause any problems. and like you think it might help.

try it and report back

+1 to Alan's comment.  People use drums because they're cheap and plentiful.  But rectangular should be fine as long as you're doing a top-hat.

[drum365]

Thanks for the info, Phil & Alan. It seemed to me like it ought to be okay, but I wasn't sure if I was missing some subtlety. I'll let you know how it works out!

[TKsDust]

I think the other consideration for a barrel/drum is they are often easier to remove and dump the waste outside the shop rather than transferring the dust/chips from a large box into a different container to be dumped. This causes a mess and generates airborne dust inside the very shop you are trying to rid of such dust.
Some have ducted the waste to a larger outside box (in a shed or closet) that can be shoveled out into a wheelbarrow, etc.