Kinetic energy, as stated. Seems that demands some consideration of mass
or force.

I think Owen already realizes that air through a tube is not the same as
trying to put 3# of the proverbial solid into a 2# bag, which answers his
question. So here's my question. If I've a 4" flex hose (standard), and
the current "standard" 1200CFM @ 11 ft of water static pressure impeller,
what percentage of my potential chip-carrying energy will I lose between
equal lengths of 6,5, or 4" inside diameter transport pipe? I figured it
would be in approximate proportion to the difference in cross-section. So
or not?


"G. Lewin" wrote in message
...
Yes, the pressure and flow rate do change (and you can use Bernoulli's
principle on a limited basis at the junction) when you change duct size.
But pressure is just a means to an end (in that pressure differences are
what move the air, of course). It is air speed that is responsible for
carrying the particles (turbulence and particle friction, in
particular). So when you say "Lower vacuum (large pipe), pieces drop" it
should really be "Lower speed...".