In article , Richard J Kinch
says...

We agree that mass flow (CFM)

Stop right there.

Mass flow and CFM are not the same thing.
Once you realize this you can begin to
think about the issue in a different way.

Cubic feet per minute is only a time
rate of volume. So in a given time
(say one minute) a give volume of material
will pass through your system.

Depending on the pressure inside the volume,
you can have all different amounts of material.
For example, a liter of gas at atmosperic
pressure has only a few atoms. If you image
the same volume at scuba tank pressure, it
has a lot more atoms inside.

Jim

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