Gilles:

I have used Edwards Supergrade A oil in two Edwards RV3 pumps for nearly a
year at the University at Albany without any problem at all.  In fact, the
oil has stayed so clean, especially in the one for the analyzer of our
Optima, that I have not needed to replace it yet.  We have run the Optima
almost exclusively for carbonate analyses to this point, but we are
analyzing samples at a rate 8000-10,000 per year, so the pumps get a
workout.

Brown oil is a sign of contamination, as you no doubt have determined.  The
only time I've seen Edwards Supergrade A oil turn brown as rapidly as you
describe is with pumps used exclusively for analyses of sulfur dioxide, as
I did at the USGS and University of Vermont.  But, even then, the oil did
not become watery.  Occasionally, when fresh oil is not ballasted properly
when it is placed in the pump, or if lots of water vapor is pumped during
sample analysis because of insufficient cryogenic or absorbent trapping, a
froth builds up on top of the oil and is visible in the sight window.  But,
again, the oil itself doesn't become watery.  Make sure that you ballast
the fresh oil when you replace it in your pumps.

Hope this helps.

Steve


>Hi all
>   We had purchased 10 RV pumps when they came out in 1994 at the Faculty
>of Sciences here at Ottawa U.  In my lab I purchased 4 of them to replace
>the aging E2M5s on the stable isotope mass specs.  The pumps were received
>with Edwards SuperGrade "A" Oil.   The Oil broke down within one to two
>months to an almost water state.  The sight glass became brown and needed
>to be removed and cleaned.  The shaft seals started leaking on one RV8 and
>it was sent for warranty repair.  The RV8 pump was returned and started
>leaking within two months.  Contact with our sales rep at the time
>indicated that the Grade "A" oil  was insufficient for these pumps because
>of the higher temperature that they ran at.  We kept operating until the
>problem was sorted out.  We changed all shaft seals and got some Ultra
>Grade 19 oilwhich was recommended.  This solved the oil breakdown but not
>the shaft seal problem.
>
>   Has anyone else out there had problems with these "new" pumps.??  Out
>of the four (two RV5s and 2 RV8s) one each are useless.  The shaft seals
>on all of them were changed 4 times except for the one RV8 where it was
>done 6 times.  The RV8 ran long enough to be out of warranty, as did the
>others..  The two others worked after Edwards sent some shaft seals with a
>spacer to move the seal down the shaft a bit.  However this is still a 50%
>failure rate.  I know that two other colleagues have had the same problem
>with more recent ones.
>
>Gilles
>
>
>Gilles St-Jean
>Technologue de Recherche
>U d'Ottawa/ Géologie/ Laboratoire d'Isotope G.G. Hatch
>140 Louis Pasteur, Ottawa, Ontario, Canada, K1N 6N5
>Bureau/Office: 1-(613) 562-5800 ext. 6839
>Lab:                                               ext. 6836
>Courier-E / E-Mail: [log in to unmask]
>Content-Type: application/ms-tnef
>
>Attachment converted: Macintosh HD:Edwards RV pumps (????/----) (0000985F)

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Stephen S. Howe                         Office:  (518) 442-5053
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