Interior Height of baffle

[kellydon]

How important is the internal Height of the baffle?

Would the Thien cyclone separate fine dust better if there was a taller gap between the bottom of the top of the lid and the top of the bottom of the baffle?
In other words, instead of the internal height being just the 2.5" size of the elbow, would a 5" or 6" internal height and then having the center exhaust port maybe even flush with the bottom of the top?

I'm just trying to make the cyclone do a better job of not sucking up so much fine dust.
Any ideas?
Thanks,
Kelly

[phil (admin)]

Unfortunately the only way to find out for sure is via some trial and error.

Typically the faster the air rotates, the better the separation.  And as you increase the distance between the baffle and the top, the volume of air above the baffle increases, and the rotation speed slows.

But things are actually a little more complex because of secondary rotations, which are much more difficult to predict.  But basically, the rotating air mass is itself comprised of many smaller rotating air masses and it is possible that when the primary rotation is too fast that turbulence allows these secondary rotations to widen and for fines to escape and exit the exhaust.

[kellydon]

Phil,
Thanks for the reply.

What about the idea of taking the exhaust port all the way through the baffle to where the exhaust air is actually coming up from below the baffle?
If so, how far down would the port need to extend into the bottom of the can?

Has anyone tried that?  Is picking up fine dust any better that way?

Would having the exhaust pipe extending through the middle of the baffle mess up the rotation?

I am using a big Rigid shop vac and a 18 gallon tall metal can.
Most of my dust is from routing, sanding, table saw, with MDF & particle board, so I get a lot of fine dust.

Thoughts?

[phil (admin)]

What about the idea of taking the exhaust port all the way through the baffle to where the exhaust air is actually coming up from below the baffle?
If so, how far down would the port need to extend into the bottom of the can?

Has anyone tried that?  Is picking up fine dust any better that way?

That won't work.  If you extend the tube under the baffle, you move the fast-moving air under the baffle as well.  So it will scrub everything from the bottom of the can.