> What is an acceptable leak rate? I am just getting into the high vacuum w=
orld
> but previously I have had a chamber at a low vacuum (30 torr), using ball
> valves from McMaster, remain under 60 torr for a month, if I recall corre=
ctly.
>=20
> It seems that high vacuum stuff I've seen often uses butterfly valves.
>=20
> Sean

If you are getting into proper vacuum stuff, then you are up for products t=
hat companies such as Lesker make for the industries that use vacuum chambe=
rs ...

Link to their valves page ...
http://www.lesker.com/newweb/valves/valves_technicalnotes_1.cfm?pgid=3D0?se=
ction=3Dtech&init=3Dskip



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