Hello Everyone,

     I'm writing to ask if anyone has taken the extra precaution to install
any type of oil trap between the roughing pumps and turbo pumps on any of
the Delta series IRMS's from what is now Thermo-Electron.  We have a Delta
Plus and recently encountered the problem of oil backstreaming into the
source turbo (Pfeiffer pumps).  We use a zeolite based oil/water trap for a
number of extraction lines where space is not an issue.  It would seem
somewhat hard to plumb this large of a trap into the compact IRMS.  Can
anyone recommend a smaller trap (NW-25 fittings) or a part number for an
additional anti-suck-back type valve?  We are currently unsure of the reason
for the oil backstreaming problem, but we certainly would like to protect
ourselves from future events.

Sincerely,

Joe Lambert
Alabama Stable Isotope Laboratory