[geeks] Bill Bradford is currently in the hospital...

[Sandwich Maker]

" From: Bill Bradford <mrbill at mrbill.net>
" 
" On Wed, Jan 24, 2007 at 08:39:31PM -0500, Sridhar Ayengar wrote:
" > Fascinating.  How much does it cost?  Something like that would be 
" > useful for a couple of things I would like to build.
" 
" Here's what I have:
" 
" http://millennium5.respironics.com/
" 
" []
" 
" Looks like they run from $600-1200.  Probably a lot cheaper used.

hmmm...  i wonder how they work?  i've heard of microporous membranes
where the pores are small enough so that the diferential diffusion
rates of n2 and o2 are meaningful, and also a 'vortex tube' which iirc
could produce a ~30% o2 stream from one end.

it doesn't sound like they're chilling the air enough to condense and
fractionate it.  it could be made efficient by transferring the heat
of condensation to the evaporation side, but it'd be complex and with
the energy investment, slow to start up.

5L/min of almost-pure o2 for only 0.6hp?  this tech would be a boon to
high-flying [over 12000'] small aircraft - a continuous supply
replacement for bottled o2.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh at an.bradford.ma.us                       and think what none thought