Re: [APML]: Re: Vacuum pump

[Brad Wallis <wallis@pepe.jpl.nasa.gov>]

the 100 micron level for the marvac R-10 is what is called "the ultimate vacuum"
that the pump can achieve ...  if you hook a pump up DIRECTLY TO A VACUUM GAUGE
it will reach the ultimate vacuum level ... if you hook it up to a leaky
tank it clearly will never reach that limit ... and if you hook it up
to a tank filled with film it may take a year for the pump to reach that level
since the film will begin some serious outgassing at about 300-400 microns
.... if you hook up to the tank through a narrow length of tube ( like
1/4 or 3/8 inch tubing ) it will take a lot longer than if you hook it up with 
a 1-inch diameter tube .. and if the tube is long it will slow the pumping
process also ....

VARIAN sells a very nice book on introductory vacuum technology ... about $25
   1-800-8VARIAN  for a catalog and/or orders...

Brad Wallis
http://voltaire.csun.edu/wallis_provin.html