Hi Michael,
We regularly use valco valves for exactly the application you refer to and
have had no problems what so ever. The only thing you have to make sure is
that you use the correct ferrules. When sealing metal on metal I would
advise using the gold plated ferrules (part number ZF1GP-10), but make sure your
sample gas is relatively inert. If you are attaching fused silica to the
valve I would suggest using an external reducing adapter, this prevent ferrules
sticking in the valve and results in a significantly better seal (part number
FS.4-5, check the catalogue if you are using fused silica with an OD greater
than 0.5mm).
Hope this helps
Cheers
Simon
p.s. the part numbers above are for 16" valve fittings
----- Original Message -----
Sent: 09 May 2006 10:09
Subject: [ISOGEOCHEM] Valco valves in
vacuum
Dear all,
I go about building a preconcentration system
for methane in small air
samples.
Did anyone use Valco switching valves
(6port, 1/8 or 1/4'', type 6UWE or
6MWE2) under vacuum conditions?
What
leak rate did you observe at which pressures? Any recommendations
concerning the switching between vacuum conditions in one postion and
non-vacuum in the other?
Any infomation will be very much
appreciated...
Regards
Michael
--
Michael Bock
Alfred
Wegener Institute for Polar and Marine Research
Am Alten Hafen 26
27568
Bremerhaven
Germany
tel: +49-471-4831-1967
lab: +49-471-4831-1026
fax: +49-471-4831-1926
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