In article , Stefek Zaba
wrote:

Mike Clarke wrote:
I don't pretend to understand the theory of cyclone extractors

Well, I do (pretend, that is); the air circulation route is shaped so
that it swirls round circularwise in (I think) an increasingly tight
spiral. Being light, air can do this; being denser, even dust can't
manage to turn the corners fast enough, so the suspended solid stuff
gets thrown out to the edges of the cylinder, which it hits and (now
away from the strongest circulation) falls to the bottom.

I get the idea of the spinning action removing the dust, it's the
dynamics of the air flow that I can't get my head round. The animation
on the Dyson website
http://www.dyson.co.uk/tech/dysoncyclone/how/difference.asp shows the
dusty air being blown into the top of the cones via the grey swirly
bits, then it spirals down inside the cone (depositing the dust as it
goes) and then goes back up the cone to leave via the straight tube in
the middle of the swirly bit. It's the idea of air moving in both
directions up and down inside the cone that I find hard to grasp.

--
Mike Clarke