Rich said:
How about two dewars? One gets filled while the other drains onto
the heat sink.
*There's* that Rich Grise thinking out of the box that we all
know and love! As with most great ideas, my first thought was
that I should have thought of that -- but I didn't.
The one being filled can be vented to the room. No back
pressure. The one cooling the CPU can be vented through
a standard pneumatic pressure regulator, and thus the 2nd
dewar will self-pressurize to achieve whatever flow rate
I choose. Even the switching is easy; there are many
small hydraulic valves with teflon interiors that can
handle liquid Nitrogen.
Brilliant! Somebody give that man a $200,000 a year job
inventing things...