Guys,
I own some 'random' diffusion pump - and as such I don't know the
proper oil charge. Inlet diameter is 3 inches, water cooled.
My question is - what will happen if the diffusion pump contains
too much oil?
I am using "Diffoil 20" from www.lesker.com - which is a low vapor
pressure hydrocarbon oil suitable for both diffusion pumps and
mechanical roughing pumps. As such I'm running the same oil in the
diffusion and the roughing pump. At $55/gal is isn't free but is
remarkable more affordable than the full synthetics!
If I have too much oil in the diffusion pump and it just gets
sucked out the foreline into the roughing pump - it sure seems like
this wouldn't matter one way or the other.
I'm thinking I'll just put in some standard charge of oil - as well
as can be guesstimated from similar pumps - and then I'll see what
happens. Can anyone provide the volumes of oil required on their
diffusion pump?
Just last night I machined up the final adapter I need to test out
some of my gauge controllers. If all is well I'll be able to try
the diffusion pump sometime soon.
If anyone is dying for the information I could extract dimensionals
off of the pump. It would be possible to build one from scratch if
you so chose. Another great source of information on these pumps is
a book called "Scientific Foundations of Vacuum Technique", by Saul
Dushman (of GE fame). I purchased a (used) copy via www.alibris.com
for $15 or such.
Thanks!
-Bill
