[AR] Re: arocket Digest V9 #9
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Sat, 16 Jan 2021 17:00:25 -0500 (EST)
On Sat, 16 Jan 2021, Keith Henson wrote:
...We didn't use a very high vacuum, as I recall, it wasn't better than
1/100th or 1/1000th of an atmosphere.
For a lot of *physical* purposes, like vacuum degassing of stuff with
bubbles full of 14.7psi air, what matters is the pressure difference...
and 14.6 or 14.69 is, as you might expect, just as good as 14.7 for
practical purposes. There is no need to bother with high vacuum.
Even a water aspirator, which only gets you down to about 0.03atm (the
vapor pressure of water at room temperature) is often good enough for such
things. (Although it uses a lot of water, and if the gas it's pulling out
contains more than just air, then the waste water may be contaminated
enough to violate rules.)
Henry
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