Dear Larry:

"Larry" wrote in message
...
"N:dlzc D:aol T:com \(dlzc\)" wrote in
newsv_Ii.42363$L_
:

What Brian left to the reader's imagination, is that the head
space of the tubes is at a near perfect vacuum, flooded only
with
water vapor. You might recall that a perfect vacuum will lift
a
column of water about 32 feet, on a high pressure day. Or had
you not figured that out?

There's a limit to the vacuum boiling. After a certain point,
water goes from a solid straight to a gas with no liquid
state, just like CO2 does at atmospheric pressure.

It actually goes into this state at very high pressures too. But
you are talking "below" the triple point, which is 0.1degC:
http://www.sv.vt.edu/classes/MSE2094...es/triple.html
.... not much of a problem above this temperature.

You can't pull a full vacuum on it and get liquid water.
http://invsee.asu.edu/ed/phase/phasefeat.htm
(see graph this website, point t.p.)

Not a full vacuum, since water vapor does fill it. And if you
boil too fast, you lose your two columns of water. And if you
don't refresh the contents of the two columns then you start
having scaling issues.

Not a slam dunk, but not a bad idea either.

David A. Smith